GOLF CLUB HEAD WITH OPEN BACK CAVITY

Description

TECHNICAL FIELD

[0001] This disclosure relates generally to golf clubs and relates more particularly to golf club heads with energy storage characteristics.

CROSS REFERENCE

BACKGROUND

[0002] Golf club manufacturers have designed golf club heads to relieve stress in the strikeface of the golf club head. In many instances, these designs do not allow the golf club head to flex in the crown to sole direction. Additionally, these designs may not change where peak bending of the golf club head occurs and do not allow additional storage of spring energy in the golf club head due to impact with the golf ball. Additional spring energy can increase ball speed across the strikeface.

[0003] US 2018/0056146 A1 disclosed an iron type golf club head with a multi-level badge that on one level contacts a rear surface of the striking face of the golf club head, and a second level of the multi-level badge contacts a rear surface of a cavity created by the chassis of the golf club head.

BRIEF DESCRIPTION OF THE DRAWINGS

[0004] To facilitate further description of the embodiments, the following drawings are provided in which:

FIG. 1 depicts a back, toe-side perspective view of a golf club head according to an embodiment;

FIG. 2 depicts a back, heel-side perspective view of the golf club head according to the embodiment of FIG. 1;

FIG. 3 depicts a cross-sectional view of the golf club head of FIG. 1 along the cross-sectional line XII-XII of FIG. 1;

FIG. 4 depicts a view of a portion of the golf club head of FIG. 3 and a view of the same area of a standard golf club head;

FIG. 5 depicts a back, toe-side perspective view of a golf club according to another embodiment;

FIG. 6 depicts a cross-sectional view of the golf club head of FIG. 5 along the cross-sectional line XVI-XVI of FIG. 5;

FIG. 7 depicts a flow diagram illustrating a method of manufacturing a golf club head according to an embodiment of another method;

FIG. 8 depicts a back perspective view of a golf club head according to yet another embodiment;

FIG. 9 depicts a back, heel-side perspective view of the golf club head according to the embodiment of FIG. 8;

FIG. 10 depicts a cross-sectional view of the golf club head of FIG. 8 along the cross-sectional line XXIV-XXIV of FIG. 8;

FIG. 11 depicts a view of a portion of the golf club head of FIG. 10 and a view of the same area of a standard golf club head;

FIG. 12 depicts a simplified cross sectional view of the golf club head of FIG. 8, similar to the detailed cross-sectional view of the golf club head in FIG. 10;

FIG. 13 depicts a back perspective view of a golf club head according to still yet another embodiment;

FIG. 14 depicts a back, heel-side perspective view of the golf club head according to the embodiment of FIG. 13;

FIG. 15 depicts a cross-sectional view of the golf club head of FIG. 13 along the cross-sectional line XXIX-XXIX of FIG. 13;

FIG. 16 depicts a view of a portion of the golf club head of FIG. 15 and a view of the same area of a standard golf club head;

FIG. 17 depicts a simplified cross-sectional view of the golf club head of FIG. 13, similar to the detailed cross-sectional view of the golf club head in FIG. 15;

FIG. 18 depicts a back perspective view of a golf club head according to still yet another embodiment;

FIG. 19 depicts a back, heel-side perspective view of the golf club head according to the embodiment of FIG. 18;

FIG. 20 depicts a cross-sectional view of the golf club head of FIG. 18 along the cross-sectional line XXXIV-XXXIV of FIG. 18;

FIG. 21 depicts a portion of the golf club head of FIG. 20;

FIG. 22 depicts a simplified cross-sectional view of the golf club head of FIG. 18, similar to the detailed cross-sectional view of the golf club head in FIG. 20;

FIG. 23 depicts a back perspective view of a golf club head according to still yet another embodiment;

FIG. 24 depicts a back, heel-side perspective view of the golf club head according to the embodiment of FIG 23;

FIG. 25 depicts a cross-sectional view of the golf club head of FIG. 23 along the cross-sectional line XXXIX-XXXIX of FIG. 23;

FIG. 26 depicts a portion of the golf club head of FIG. 25;

FIG. 27 depicts a simplified cross-sectional view of the golf club head of FIG. 23, similar to the detailed cross-sectional view of the golf club head in FIG. 25;

FIG. 28 depicts an interior view of a portion of the golf club head of FIG. 23;

FIG. 29 depicts a front perspective view of the golf club head of FIG. 23;

FIG. 30 depicts a back perspective view of a golf club head according to still yet another embodiment;

FIG. 31 depicts a back, heel-side perspective view of the golf club head according to the embodiment of FIG. 30;

FIG. 32 depicts a cross-sectional view of the golf club head of FIG. 30 along the cross-sectional line XLVI-XLVI of FIG. 30;

FIG. 33 depicts a portion of the golf club head of FIG. 32;

FIG. 34 depicts a simplified cross-sectional view of the golf club head of FIG. 30, similar to the detailed cross-sectional view of the golf club head in FIG. 33.

FIG. 35 depicts a back perspective view of a golf club head according to still yet another embodiment;

FIG. 36 depicts a back, heel-side perspective view of the golf club head according to the embodiment of FIG. 35;

FIG. 37 depicts a cross-sectional view of the golf club head of FIG. 35 along the cross-sectional line LI-LI of FIG. 35;

FIG. 38 depicts a portion of the golf club head of FIG. 35;

FIG. 39 depicts a simplified cross-sectional view of the golf club head of FIG. 35, similar to the detailed cross-sectional view of the golf club head in FIG. 37.

FIG. 40 depicts an interior view of a portion of the golf club head of FIG. 35;

FIG. 41 depicts a front perspective view of the golf club head of FIG. 35;

FIG. 42 depicts a back perspective view of a golf club head according to still yet another embodiment;

FIG. 43 depicts a back, heel-side perspective view of the golf club head according to the embodiment of FIG. 42;

FIG. 44 depicts a cross-sectional view of the golf club head of FIG. 42 along the cross-sectional line LVIII-LVIII of FIG. 42;

FIG. 45 depicts a portion of the golf club head of FIG. 44;

FIG. 46 depicts a simplified cross-sectional view of the golf club head of FIG. 42, similar to the detailed cross-sectional view of the golf club head in FIG. 45;

FIG. 47 depicts a cross-sectional view of the heel portion of the golf club head of FIG. 42, along the cross-sectional line LXI-LXI; and

FIG. 48 depicts an front view of the golf club head of FIG. 42, along the cross-sectional line LXII-LXII.

FIG. 49 is a back perspective view of a golf club head.

FIG. 50 is a back, heel-side perspective view of the golf club head of FIG. 49.

FIG. 51 is a front, toe-side perspective view of the golf club head of FIG. 49.

FIG. 52 is a front, toe-side exploded perspective view of the golf club head of FIG. 49.

FIG. 53 is a front, heel-side perspective view of the golf club head of FIG. 49 with portions removed.

FIG. 54 is a back perspective view of the golf club head of FIG. 49 with portions removed.

FIG. 55 is a cross-sectional view of the golf club head of FIG. 49 taken along line 7-7 of FIG. 49.

FIG. 56 is another cross-sectional view of the golf club head of FIG. 49 taken along line 8-8 of FIG. 49.

FIG. 57 is another cross-sectional view of a portion of the golf club head of FIG. 49 taken along line 7-7 of FIG. 49.

FIG. 58 is another cross-sectional view of the golf club head of FIG. 49 taken along line 7-7 of FIG. 49, similar to the cross-sectional view of FIG. 55.

FIGS. 59A-59D are rear perspective views of the golf club head of FIG. 49 including different embodiments of a badge as disclosed herein.

FIG. 60A-60D are cross-sectional views of the golf club head of FIG. 49 including a filler material as disclosed herein.

[0005] For simplicity and clarity of illustration, the drawing figures illustrate the general manner of construction, and descriptions and details of well-known features and techniques may be omitted to avoid unnecessarily obscuring the golf clubs and their methods of manufacture. Additionally, elements in the drawing figures are not necessarily drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help improve understanding of embodiments of the golf clubs and their methods of manufacture. The same reference numerals in different figures denote the same elements.

[0006] The terms "first," "second," "third," "fourth," and the like in the description and in the claims, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of golf clubs and methods of manufacture described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "contain," "include," and "have," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to those elements, but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0007] The terms "left," "right," "front," "back," "top," "bottom," "side," "under," "over," and the like in the description and in the claims, if any, are used for descriptive purposes and not necessarily for describing permanent relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of golf clubs and methods of manufacture described herein are, for example, capable of operation in other orientations than those illustrated or otherwise described herein. The term "coupled," as used herein, is defined as directly or indirectly connected in a physical, mechanical, or other manner.

SUMMARY OF THE INVENTION

[0008] The present invention is directed to a golf club head as defined in the appended claims. In particular, the present invention is directed to a golf club head comprising:

a body having a sole and a top rail opposite the sole;

a faceplate defining a strikeface;

a back wall opposite the strikeface;

a back cavity defined within the golf club head between the faceplate, the back wall, the sole, and the top rail;

an indention formed in the back wall and extending toward the strikeface;

a rear opening defined within the indention, the rear opening communicating with the back cavity at or proximate an exterior of the golf club head;

wherein a midplane divides the strikeface into an upper region and a lower region by extending through a geometric center of the strikeface and perpendicular thereto between the top rail and the sole; and 100% of the area of the rear opening is positioned between the midplane and the top rail.

OUTLINE OF THE DISCLOSURE

[0009] Various embodiments of golf club heads with energy storage characteristics include a golf club head comprising a hollow body. The hollow body comprises a strikeface, a heel region, a toe region opposite the heel region, a sole, and a crown. In many embodiments, the crown comprises an upper region comprising a top rail, and a lower region. In some embodiments, a cavity is located below the top rail, is located above the lower region of the crown, and is defined at least in part by the upper and lower regions of the crown. In many embodiments, the cavity comprises a top wall, a back wall, a bottom incline, a back cavity angle measured between the top and back walls of the cavity, and at least one channel.

[0010] Some embodiments include a golf club comprising a hollow-bodied golf club and a shaft coupled to the hollow-bodied golf club head. The hollow-bodied golf club head comprises a strikeface, a heel region, a toe region opposite the heel region, a sole, and a crown. In many embodiments, the crown comprises an upper region comprising a top rail, and a lower region. In some embodiments, a cavity is located below the top rail, is located above the lower region of the crown, and is defined at least in part by the upper and lower regions of the crown. In many embodiments, the cavity comprises a top wall, a back wall, a bottom incline, a back cavity angle measured between the top and back walls of the cavity, and at least one channel.

[0011] Other embodiments include a method for manufacturing a golf club head. In many embodiments, the method comprises providing a body. The body having a strikeface, a heel region, a toe region opposite the heel region, a sole, and a crown. The crown comprises an upper region comprising a top rail and a lower region. In some embodiments, a cavity is located below the top rail, above the lower region of the crown, and is defined at least in part by the upper and lower regions of the crown. In many embodiments, the cavity comprises a top wall, a back wall adjacent to the top wall, a bottom incline adjacent to the back wall, a back cavity angle measured between the top and back walls of the cavity, and at least one channel.

[0012] Various embodiments include a golf club head comprising a hollow body. The hollow body comprises a strikeface, a heel region, a toe region opposite the heel region, a sole, and a crown. In many embodiments, the crown comprises an upper region comprising a top rail, and a lower region comprising a lower exterior wall. In some embodiments, a cavity is located below the top rail, is located above the lower region of the crown, and is defined at least in part by the upper and lower regions of the crown. In many embodiments, the cavity comprises a top wall, a back wall, a first inflection point adjacent the top wall and the back wall, a bottom incline, a second inflection point adjacent to the back wall and the bottom incline, a third inflection point adjacent to the bottom incline and the lower exterior wall, a lower angle measured from between the bottom incline and the lower exterior wall, the lower angle is less than 180 degrees, a back cavity angle measured between the top and back walls of the cavity, and at least one channel.

[0013] Some embodiments include a golf club comprising a hollow-bodied golf club and a shaft coupled to the hollow-bodied golf club head. The hollow-bodied golf club head comprises a strikeface, a heel region, a toe region opposite the heel region, a sole, and a crown. In many embodiments, the crown comprises an upper region comprising a top rail, and a lower region comprising a lower exterior wall. In some embodiments, a cavity is located below the top rail, is located above the lower region of the crown, and is defined at least in part by the upper and lower regions of the crown. In many embodiments, the cavity comprises a top wall, a back wall, a first inflection point adjacent the top wall and the back wall, a bottom incline, a second inflection point adjacent to the back wall and the bottom incline, a third inflection point adjacent to the bottom incline and the lower exterior wall, a lower angle measured from between the bottom incline and the lower exterior wall, the lower angle is less than 180 degrees, a back cavity angle measured between the top and back walls of the cavity, and at least one channel.

[0014] Other embodiments include a method for manufacturing a golf club head. In many embodiments, the method comprises providing a body. The body having a strikeface, a heel region, a toe region opposite the heel region, a sole, and a crown. The crown comprises an upper region comprising a top rail and a lower region comprising a lower exterior wall. In some embodiments, a cavity is located below the top rail, above the lower region of the crown, and is defined at least in part by the upper and lower regions of the crown. In many embodiments, the cavity comprises a top wall, a back wall, a first inflection point adjacent the top wall and the back wall, a bottom incline, a second inflection point adjacent to the back wall and the bottom incline, a third inflection point adjacent to the bottom incline and the lower exterior wall, a lower angle measured from between the bottom incline and the lower exterior wall, the lower angle is less than 180 degrees, a back cavity angle measured between the top and back walls of the cavity, and at least one channel.

[0015] Some embodiments include a golf club head including a body comprising a partial back cavity located in an interior of the body. The club head, includes a faceplate coupled to the body at a front end, defining a striking surface or strike face, and a cover or badge coupled to the body at a back end, opposite the front end. In some embodiments, as described below, the badge may be a partial badge, or the badge may be omitted entirely from the club head. In addition to the front end and the back end, the body includes a heel region, a toe region opposite the heel region, a sole, and a top rail opposite the sole. The partial back cavity contributes to a dynamic deflection or spring effect of the body when striking a golf ball.

[0016] Other examples and embodiments are further disclosed herein. Such examples and embodiments may be found in the figures, in the claims, and/or in the present description.

I. Golf Club Head with Back Cavity

[0017] In one embodiment, the golf club head has a back cavity located in an upper crown area of the golf club. In many embodiments, the back cavity can provide a box spring affect when striking a golf ball. The back cavity can be combined with varying thicknesses of the internal radius of the sole of the club head (cascading sole) to provide a spring like effect.

[0018] Some embodiments are directed to a club head (hybrid or fairway wood or iron with hollow design) that features a hollowed construction club head that provides a more "iron-like" look and feel. In some embodiments, the golf club head can feature a flat strikeface and iron-like profile, which can provide improved workability and accuracy, similar to an iron. A back cavity located below a top rail and along the upper crown of the club head has been designed for hybrids, fairway woods and irons with a hollow construction. The back cavity may be a full channel from the heel to the toe just below the top rail and along the upper crown or back portion of the club head. The top rail and the cavity may be any design. In some embodiments, the cavity is angled at approximately 90 degrees and provides a targeted hinge point in the crown region of the golf club head. This hinge or buckling region enables the top rail to absorb more of the impact force over a wider volumetric area causing the cavity and the top rail to act as a springboard by returning more recoiled force back to the strikeface as it returns to its original orientation thereby imparting more force into the ball. This greater club face deflection by the cavity design can lead to less spin, a higher loft angle of the golf ball upon impact, and greater ball speed with the same club speed over standard golf club heads.

[0019] In a standard hybrid club head, the top rail and upper crown regions do not have a cavity of this design. In comparison to the present disclosure, there is less club strikeface bending or deflection in such a standard hybrid club head. Standard hybrids are unable to have as great a spring-back effect because less energy is transferred to the top rail of the club due to the lack of a cavity. The disclosed golf club head with back cavity allows more of the impact force of the golf ball to be absorbed and then returned to the strikeface. In many embodiments, the angle of the cavity can provide a buckling point, or plastic hinge, or targeted hinge, for the strikeface to deflect more over the standard golf club.

[0020] The recoiling effect of the cavity on the strikeface provides: (1) a higher golf ball speed relative to the same club head speed of a club head with an upper crown cavity (or back cavity) and one without, due in part to the spring effect that is transferred from the hinged region to the strikeface to the ball; (2) less spin of the golf ball after impact with the club, due in part to the hinge point above the cavity counters more force being absorbed by the club and instead transfers more force to the ball thereby preventing the ball from spinning backward off the strikeface; and/or (3) a higher loft angle to the golf ball upon impact, due to the hinge and strikeface acting as a diving board or catapult to the ball. In some embodiments, the cavity may provide an increase in ball speed of approximately 1.0 - 1.2%, and an increase in launch angle of approximately 0.4 - 0.7 degrees.

[0021] Turning back to the drawings, FIG. 1 illustrates a back toe-side perspective view of an embodiment of golf club head 1000 and FIG. 2 illustrates a back heel-side perspective view of golf club head 1000 according to the embodiment of FIG. 1. Golf club head 1000 can be a hybrid-type golf club head. In other embodiments, golf club head 1000 can be an iron-type golf club head or a fairway wood-type golf club head. In many embodiments, golf club head 1000 does not include a badge or a custom tuning port.

[0022] Golf club head 1000 comprises a body 1001. In many embodiments, the body is hollow. In some embodiments, the body is at least partially hollow. Body 1001 comprises a strikeface 1012, a heel region 1002, a toe region 1004 opposite heel region 1002, a sole 1006, and a crown 1008. Crown 1008 comprises an upper region 1011 and a lower region 1013. Upper region 1011 comprises a top rail 1015. The top rail 1015 begins in the toe region 1004, adjacent a top edge of the strikeface 1012, and extends along the top of the golf club head 1000 towards the heel region 1002. From a cross-sectional side view, such as in FIG. 3, the top rail 1015 begins at the transition between the strikeface 1012 and a top of the golf club head 1000 and ends at the transition between the top of the crown 1008 of the golf club head 1000 and a section of the crown with a different orientation, such as a rear wall 1023. In some embodiments, top rail 1015 can be a flatter and taller top rail than in irons known to one skilled in the art. The flatter and taller top rail can compensate for mishits on strikeface 1012 to increase playability off the tee.

[0023] In some embodiments, body 1001 can comprise stainless steel, titanium, aluminum, a steel alloy (e.g. 455 steel, 475 steel, 431 steel, 17-4 stainless steel, maraging steel), a titanium alloy (e.g. Ti 7-4, Ti 6-4, T-9S), an aluminum alloy, or a composite material. In some embodiments, strikeface 1012 can comprise stainless steel, titanium, aluminum, a steel alloy (e.g. 455 steel, 475 steel, 431 steel, 17-4 stainless steel, maraging steel), a titanium alloy (e.g. Ti 7-4, Ti 6-4, T-9S), an aluminum alloy, or a composite material. In some embodiments, body 1001 can comprise the same material as strikeface 1012. In some embodiments, body 1001 can comprise a different material than strikeface 1012.

[0024] In many embodiments, a cavity 1030 is located below top rail 1015. In many embodiments, cavity 1030 comprises a top rail box spring design. In many embodiments, top rail 1015 and cavity 1030 provide an increase in the overall bending of strikeface 1012. In some embodiments, the bending of strikeface 1012 can allow for an approximately 2% to approximately 5% increase of energy. The cavity 1030 allows for the strikeface 1012 to be thinner and allow additional overall bending. For some fairway wood-type golf club head embodiments, cavity 1030 can be a reverse scoop or indentation of crown 1008 with body 1001 comprising a greater thickness or width toward sole 1006.

[0025] Referring to FIG. 1 in some embodiments, golf club head 1000 can further comprise an insert 1062 at lower region 1013 of crown 1008 towards toe region 1004. Some embodiments comprise an internal weight at sole 1006. In many embodiments, insert 1062 may be comprised of tungsten or some other high density material. In many embodiments, the insert shifts the center of gravity (CG) back from strikeface 1012 by approximately 1 mm (0.04 inch) to 2.5 mm (0.10 inch) and provides a 3.5% to 5.5% increase in launch angle, which can lead to an increase of playability off the tee and high or low mishits.

[0026] In many embodiments, the CG is in lower region 1013 of crown 1008, close to the intersection of toe region 1004 and sole 1006. In some embodiments, the CG of golf club head 1000 is 15.2 mm (0.597 inches) along the CGy plane and 13.7 mm (0.541 inches) along the CGz plane. For the moment of inertia, Ixx, there was a 20.5% increase over the G30 iron and a 28% increase over the Rapture DI by golf club head 1000. For Iyy, there was a 1.7% increase over the G30 iron and a 22% increase over Rapture DI.

[0027] In some embodiments, approximately 3 grams (g) to approximately 4 g is added to top rail 1015. In most embodiments, the overall mass of golf club head 1000 remains the same. In some embodiments, mass can be removed from sole 1006 or toe region 1004 to offset the addition of mass to top rail 1015. In some embodiments, adding the approximately 3 g to approximately 4 g of mass to top rail 1015 can assist in the golf club head resisting turning. In some embodiments, the CG of the golf club head is slightly raised.

[0028] FIG. 3 illustrates a cross-section of golf club head 1000 along the cross-sectional line XII-XII in FIG. 1, according to one embodiment. As seen in FIG. 3, strikeface 1012 comprises a high region 1076, a middle region 1074, and a low region 1072. In many embodiments, upper region 1011 of crown 1008 comprises the rear wall 1023, a top wall 1017 of cavity 1030 below and adjacent to rear wall 1023, and a back wall 1019 of cavity 1030 below and adjacent to top wall 1017.

[0029] In some embodiments, a height 1280 of rear wall 1023 of the upper region 1011 of crown 1008 can be approximately 0.318 cm (0.125 inch) to approximately 1.91 cm (0.75 inch), or approximately 0.381 cm (0.150 inch) to approximately 1.02 cm (0..400 inch). For example, in some embodiments, the height 1280 of rear wall 1023 of the upper region 1011 of crown 1008 can be approximately 0.445 cm (0.175 inch), 0.699 cm (0.275 inch), 0.953 cm (0.375 inch), 1.21 cm (0.475 inch), 1.46 cm (0.575 inch), or 1.71 cm (0.675 inch). In some embodiments, the height 1280 of rear wall 1023 of the upper region 1011 of crown 1008 can be approximately 5% to approximately 25% of the height of golf club head 1000. In some embodiments, the length of top rail 1015, measured from heel region 1002 to toe region 1004, can be approximately 70% to approximately 95% of the length of golf club head 1000.

[0030] The height 1280 of rear wall 1023 of the upper region 1011 of crown 1008, as described herein, allows cavity 1030 to absorb at least a portion of the stress on strikeface 1012 during impact with a golf ball. A golf club head having a rear wall height greater than the rear wall height 1280 described herein would absorb less stress (and allow less strikeface deflection) on impact than the golf club head 1000 described herein, due to increased dispersion of the impact stress along the top rail prior to reaching the cavity.

[0031] In some embodiments, cavity 1030 is located above lower region 1013 of crown 1008 and is defined at least in part by upper region 1011 and lower region 1013 of crown 1008. Cavity 1030 comprises a top wall 1017, a back wall 1019, and a bottom incline 1021. A first inflection point 1082 is located between top wall 1017 of cavity 1030 and rear wall 1019 of cavity. A second inflection point 1086 is located between rear wall 1019 of cavity 1030 and bottom incline 1021.

[0032] The top wall 1017 and the rear wall 1019 of the external cavity 1030 hinge about the first inflection point 1082. This hinge-like mobility at the first inflection point 1082 allows greater strikeface 1012 deflection.

[0033] In some embodiments, the height of back wall 1019, measured from first inflection point 1082 to second inflection point 1086, can be approximately 0.25 mm (0.010 inch) to approximately 3.5 mm (0.138 inch), or approximately 0.5 mm (0.010 inch) to approximately 1.5 mm (0.059 inch). For example, the height of back wall 1019 can be approximately 0.25 mm (0.010 inch), 0.5 mm (0.020 inch), 0.75 mm (0.030 inch), 1.0 mm (0.040 inch), 1.25 mm (0.050 inch), 1.5 mm (0.060 inch), 1.75 mm (0.070 inch), 2.0 mm (0.080 inch), 2.25 mm (0.090 inch), 2.5 mm (0.100 inch), 2.75 mm (0.110 inch), 3.0 mm (0.012 inch), 3.25 mm (0.13 inch), or 3.5 mm (0.14 inch). In many embodiments, an apex of top wall 1017 can be approximately 0.318 cm (0.125 inch) to approximately 3.18 cm (1.25 inches) or approximately 0.635 cm (0.25 inch) to approximately 3.18 cm (1.25 inches) below an apex of top rail 1015. For example, the apex of top wall 1017 can be approximately 0.318 cm (0.125 inch), 0.635 cm (0.25 inch), 0.953 cm (0.375 inch), 1.27 cm (0.5 inch), 1.59 cm (0.625 inch), 1.91 cm (0.75 inch), 2.10 cm (0.825 inch), 2.54 cm (1.0 inch), 2.88 cm (1.125 inch), or 3.18 cm (1.25 inches) below the apex of top rail 1015.

[0034] In many embodiments, back wall 1019 of cavity 1030 can be substantially parallel to strikeface 1012. In other embodiments, back wall 1019 is not substantially parallel to strikeface 1012. In many embodiments, top wall 1017 of cavity is angled toward strikeface 1012 when moving toward the first inflection point 1082. This orientation of top wall 1017 creates a buckling point or hinge point or plastic hinge to direct the stress of impact toward cavity 1030 and allowing increased flexing of strikeface 1012 during impact.

[0035] Lower region 1013 of crown 1008 comprises bottom incline 1021 of cavity 1030. In many embodiments, the second inflection point 1086, adjacent to bottom incline 1021, can be at least approximately 0.25 inch (0.635 cm) to approximately 2.0 inches (5.08 cm), or approximately 0.5 inch (1.27 cm) to approximately 1.5 inches (3.81 cm) below the apex of top rail 1015. For example, the second inflection point 1086 can be at least approximately 0.25 inch (0.635 cm), 0.5 inch (1.27 cm), 0.75 inch (1.91 cm), 1.0 inch (2.53 cm), 1.25 inches (3.18 cm), 1.5 inches (3.81 cm), 1.75 inches (4.45 cm) or 2.0 inches (5.08 cm) below the apex of top rail 1015. In some embodiments, the maximum height of the bottom incline, measured from the sole 1006 of the club head 1000 to the second inflection point 1086, can be at least approximately 0.25 inch (0.635 cm) to approximately 3 inches (7.62 cm), or approximately 0.50 inch (1.27 cm) to approximately 2 inches (5.08 cm) above a lowest point of the sole 1006. For example, the second inflection point 1086 can be at least approximately 0.25 inch (0.635 cm), 0.375 inch (0.953 cm), 0.5 inch (1.27 cm), 0.625 inch (1.59 cm), 0.75 inch (1.91 cm), 0.825 inch (2.10 cm), 1.0 inch (2.54 cm), 1.125 inches (2.88 cm), 1.25 inches (3.18 cm), 1.375 inches (3.49 cm), 1.5 inches (3.81 cm), 1.625 inches (4.12 cm), 1.75 inches (4.45 cm), 1.875 inches (4.76 cm), 2.0 inches (5.08 cm), 2.125 inches 5.40 cm), 2.25 inches (5.71 cm), 2.375 inches (6.03 cm), 2.5 inches (6.35 cm), 2.625 inches (6.67 cm), 2.75 inches (7.00 cm), 2.875 inches (7.30 cm), or 3.0 inches (7.62 cm) above a lowest point of the sole.

[0036] Cavity 1030 further comprises at least one channel 1039 (FIG. 1). In many embodiments, channel 1039 extends from heel region 1002 to toe region 1004. A channel width 1032 (FIG. 3) can be substantially constant throughout channel 1039. In some embodiments, channel width 1032 (FIG. 3) can be approximately 0.2 mm (0.008 inch) to approximately 25 mm (1 inch), or approximately 0.2 mm (0.008 inch) to approximately 8 mm (0.31 inch). For example, channel width 1032 can be approximately 0.2 mm (0.008 inch), 0.4 mm (0.016 inch), 0.6 mm (0.024 inch), 0.8 mm (0.031 inch), 1.0 mm (0.039 inch), 2 mm (0.079 inch), 3 mm (0.12 inch), 4 mm (0.16 inch), 5 mm (0.20 inch), 6 mm (0.24 inch), 7 mm (0.28 inch), 8 mm (0.31 inch), 10 mm (0.39 inch), 15 mm (0.59 inch), 20 mm (0.79 inch), or 25 mm (0.98 inch). In other embodiments, a channel toe region width of channel 1039 is smaller than a channel heel region width of channel. In other embodiments, the channel heel region width is smaller than the channel toe region width. In other embodiments, a channel middle region width of channel 1039 can be smaller than at least one of the channel heel region width or the channel toe region width. In other embodiments, the channel middle region width can be greater than at least one of the channel heel region width or the channel toe region width. In some embodiments, channel 1039 is symmetrical. In other embodiments, channel 1039 is non-symmetrical. In other embodiments, channel 1039 can further comprise at least two partial channels. In some embodiments, channel 1039 can comprise a series of partial channels interrupted by one or more bridges. In some embodiments, the one or more bridges can be approximately the same thickness as the thickness of upper region 1011 of crown 1008.

[0037] The channel width 1032, as described herein, allows absorption of stress from strikeface 1012 on impact. A golf club head having a channel width less than the channel width described herein (e.g. a golf club head with a less pronounced cavity) would allow less stress absorption from the strikeface on impact (due to less material on the upper region 1011 of crown 1008), and therefore would experience less strikeface deflection than the golf club head 1000 described herein.

[0038] In many embodiments, cavity 1030 further comprises a back cavity angle 1035. Back cavity angle is measured between top wall 1017 and back wall 1019 of cavity 1030. In many embodiments, back cavity angle 1035 can be approximately 70 degrees to approximately 110 degrees. In some embodiments, back cavity angle 1035 can be approximately 80 degrees to approximately 100 degrees. In some embodiments, back cavity angle 1035 is approximately 70, 75, 80, 85, 90, 95, 100, or 110 degrees. In many embodiments, back cavity angle 1035 provides a buckling point or plastic hinge or targeted hinge at a top rail hinge point 1070, upon golf club head 1000 impacting the golf ball. In some embodiments, the wall thickness at top rail hinge point 1070 is thinner than at top wall 1017 of cavity 1030

[0039] FIG. 4 illustrates a view of crown 1008 of the cross-section of golf club head 1000 of FIG. 3 alongside a similar cross-section of a golf club head 1200 without a cavity along a similar cross-sectional line XII-XII in FIG. 1. Golf club head 1200 comprises a strikeface 1212, a crown 1208, a top rail 1215, a top rail hinge point 1270, and a rear wall 1223. In many embodiments, golf club head 1000 comprises a rear angle 1040, a top rail angle 1045, and a strikeface angle 1050. Upper region angle 1040 is measured from top wall 1017 to rear wall 1023 of upper region 1011. In many embodiments, rear angle 1040 can be approximately 70 degrees to approximately 110 degrees. In some embodiments, rear angle 1040 is approximately 90 degrees. Top rail angle 1045 is measured from rear wall 1023 of upper region 1011 to top rail 1015. In many embodiments, top rail angle 1045 can be approximately 35 degrees to approximately 120 degrees or 70 degrees to approximately 110 degrees. In some embodiments, top rail angle 1045 can be approximately 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, or 120 degrees. Strikeface angle 1050 is measured from strikeface 1012 to top rail 1015. In many embodiments, strikeface angle 1050 can be approximately 70 degrees to approximately 160 degrees or 70 degrees to approximately 110 degrees. In some embodiments, strikeface angle 1050 is approximately 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 155, or 160 degrees.

[0040] Referring to FIG. 4, in some embodiments, a minimum gap 1090 between strikeface 1012 and back wall 1019 is approximately 2 mm (0.079 inch) to approximately 10 mm (0.39 inch). For example, the minimum gap 1090 between strikeface 1012 and back wall 1019 can be approximately 2 mm (0.079 inch), 4 mm (0.16 inch), 6 mm (0.24 inch), 8 mm (0.31 inch), or 10 mm (0.39 inch). In some embodiments, the minimum gap 1090 between the strikeface 1012 and back wall 1019 is less than approximately 14 mm (0.55 inch), less than approximately 12 mm (0.47 inch), less than approximately 10 mm (0.39 inch), less than approximately 8 mm (0.31 inch), less than approximately 6 mm (0.24 inch), or less than approximately 4 mm (0.16 inch). Further, in some embodiments, a maximum gap between strikeface 1012 and rear wall 1023 of upper region 1011 of golf club head 1000 is greater than minimum gap 1090. Further still, in some embodiments, a maximum gap between strikeface 1012 and bottom incline 1021 in lower region 1013 of golf club head 1000 is greater than minimum gap 1090 and maximum gap in upper region 1011.

[0041] In many embodiments, cavity 1030 can provide an increase in golf ball speed over golf club head 1200 or other standard golf club heads, can reduce the spin rate of standard hybrids club heads, and can increase the launch angle over both the standard hybrid and iron club heads. In many embodiments, the shape of cavity 1035 determines the level of spring and timing of the response of golf club head 1000. When the golf ball impacts strikeface 1012 of club head 1000 with cavity 1030, strikeface 1012 springs back like a drum, and crown 1008 bends in a controlled buckle manner. In many embodiments, top rail 1015 can absorb more stress over greater volumetric space than a top rail in a golf club head without cavity 1030. The length, depth and width of cavity 1030 can vary. These parameters provide control regarding how much spring back is present in the overall design of club head 1000.

[0042] Upon impact with the golf ball, strikeface 1012 can bend inward at a greater distance than on a golf club without cavity 1030. In some embodiments, strikeface 1012 has an approximately 10% to approximately 50% greater deflection than a strikeface on a golf club head without cavity 1030. In some embodiments, strikeface 1012 has an approximately 5% to approximately 40% or approximately 10% to approximately 20% greater deflection than a strikeface on a golf club head without cavity 1035. For example, strikeface 1012 can have an approximately 5%, 10%, 15%, 20%, 25%, 30%, 35% or 40% greater deflection than a strikeface on a golf club head without cavity 1035. In many embodiments, there is both a greater distance of retraction by strikeface 1012 due to the hinge and bending of cavity 1030 over a standard strikeface that does not have a back portion of the club without the cavity.

[0043] In many embodiments, the face deflection is greater with club head 1000 having cavity 1030, as a greater buckling occurs along top rail hinge point 1070 upon impact with the golf ball. Cavity 1030, however, provides a greater dispersion of stress along top rail hinge point 1070 region of the top rail and the spring back force is transferred from cavity 1030 and top rail 1015 to strikeface 1012. A standard top rail without a cavity does not have this hinge/buckling effect, nor does it absorb a high level of stress over a large volumetric area of the top rail. Therefore, the standard strikeface does not contract and then recoil as much as strikeface 1012. Further, both a larger region of strikeface 1012 and top rail 1015 absorb more stress than the same crown region of a standard golf club head with a standard top rail and no cavity. In many embodiments, although there is greater stress along a greater area above cavity 1030 than the same area in a standard club without the cavity, the durability of the club head with and without the cavity is the same. By adding more spring to the back end of the club (due to the inward inclination of top wall 1017 toward strikeface 1012), more force is displaced throughout the volume of the structure. The stress is observed over a greater area of strikeface 1012 and top rail 1015 of golf club head 1000. Peak stresses can be seen in the standard top rail club head. However, more peak stresses are seen in golf club head 1000 but distributed over a large volume of the material. The hinge and bend regions of golf club head 1000 (i.e., the region above cavity 1030 and cavity 1030 itself) will not deform as long as the stress does not meet the critical buckling threshold. Cavity 1030 and its placement can be designed to be under the critical K value of the buckling threshold.

[0044] Turning ahead in the drawings, FIG. 8 illustrates a back perspective view of an embodiment of golf club head 2200 and FIG. 9 illustrates a back heel-side perspective view of golf club head 2200 according to the embodiment of FIG. 8. In some embodiments, golf club head 2200 can be similar to golf club head 1000 (FIG. 1). Golf club head 2200 can be a hybrid-type golf club head. In other embodiments, golf club head 2200 can be an iron-type golf club head or a fairway wood-type golf club head. In many embodiments, golf club head 2200 does not include a badge or a custom tuning port.

[0045] Golf club head 2200 comprises a body 2201. In some embodiments, body 2201 can be similar to body 1001 (FIG. 1). In many embodiments, the body is hollow. In some embodiments, the body is at least partially hollow. Body 2201 comprises a strikeface 2212, a heel region 2202, a toe region 2204 opposite heel region 2202, a sole 2206, and a rear 2210. Rear 2210 comprises an upper region 2211 and a lower region 2213. Upper region 2211 comprises a top rail 2215. The top rail 2215 can be similar to the top rail 1015 of golf club head 1000. In some embodiments, top rail 2215 can be a flatter and taller top rail than in the in irons known to one skilled in the art. The flatter and taller top rail can compensate for mis-hits on strikeface 2212 to increase playability off the tee.

[0046] Body 2201 of FIGS. 8-12 further comprises a blade length. The blade length for body 2201 can be measured similar to blade length 3725 as shown and described in FIG. 29 (i.e., a measurement parallel to the flat surface of the strikeface 3712, from a toe edge 3726 of the strikeface 3712, to strikeface end 3727 right before the strikeface 3712 integrally curves into the hosel). The blade length of the body 2201 can range from approximately 7.11 cm (2.80 inches) to approximately 7.62 cm (3.00 inches). For example, in some embodiments, the body 2201 can comprise a blade length of approximately 7.11 cm (2.80 inches), 7.16 cm (2.82 inches), 7.21 cm (2.84 inches), 7.26 cm (2.86 inches), 7.32 cm (2.88 inches), 7.37 cm (2.90 inches), 7.44 cm (2.93 inches), 7.47 cm (2.94 inches), 7.52 cm (2.96 inches), 7.57 cm (2.98 inches), or 7.62 cm (3.00 inches).

[0047] .The body 2201 further comprises a uniform thinned region transitioning from the bottom of the strikeface 2212 to the sole 2206, toward a cascading sole portion of the sole (as described in greater detail below). In the illustrated embodiment, the uniform thinned region comprises a sole thickness measured perpendicular from the exterior surface 2225 to the interior surface at the uniform thinned region, which can remain constant from the bottom of the strikeface 2212 to adjacent the cascading sole portion of the sole. In some embodiments, the sole thickness of the uniform thinned region can be thinner than a conventional sole. For example, in some embodiments, the sole thickness of the uniform thinned region may range from approximately 1.02 mm (0.040 inch) to 2.03 mm (0.080 inch). In other embodiments, the sole thickness of the uniform thinned region may be within the range of 1.02 mm (0.040 inch) to 1.27 mm (0.050 inch), 1.27 mm (0.050 inch) to 1.52 mm (0.060 inch), 1.52 mm (0.060 inch) to 1.78 mm (0.070 inch), 1.78 mm (0.070 inch) to 2.03 mm (0.080 inch), 1.02 mm (0.040 inch) to 1.40 mm (0.055 inch), 1.14 mm (0.045 inch) to 1.52 mm (0.060 inch), 1.27 mm (0.050 inch) to 1.65 mm (0.065 inch), 1.40 mm (0.055 inch) to 1.78 mm (0.070 inch), 1.52 mm (0.060 inch) to 1.91 mm (0.075 inch), or 1.65 mm (0.065 inch) to 2.03 mm (0.080 inch). For example, the sole thickness of the uniformed thinned region can be 1.02 mm (0.040 inch), 1.14 mm (0.045 inch), 1.27 mm (0.050 inch), 1.52 mm (0.060 inch), 1.65 mm (0.065 inch), 1.78 mm (0.070 inch), 1.91 mm (0.075 inch), or 2.03 mm (0.080 inch).

[0048] In some embodiments, body 2201 can comprise stainless steel, titanium, aluminum, a steel alloy (e.g. 455 steel, 475 steel, 431 steel, 17-4 stainless steel, maraging steel), a titanium alloy (e.g. Ti 7-4, Ti 6-4, T-9S, Ti SSAT2041, Ti SP700, Ti 15-0-3, Ti 15-5-3, Ti 3-8-6-4-4, Ti 10-2-3, Ti 15-3-3-3, Ti-6-6-2, Ti-185, or any combination thereof), an aluminum alloy, or a composite material. In other embodiments, body 2201 can comprise carpenter grade 455 steel, carpenter grade 475 steel, C300 steel, C350 steel, a Ni-Co-Cr steel alloy, a quench and tempered steel alloy, or 565 steel. In some embodiments, strikeface 2212 can comprise stainless steel, titanium, aluminum, a steel alloy (e.g. 455 steel, 475 steel, 431 steel, 17-4 stainless steel, maraging steel), a titanium alloy (e.g. Ti 7-4, Ti 6-4, T-9S, Ti SSAT2041, Ti SP700, Ti 15-0-3, Ti 15-5-3, Ti 3-8-6-4-4, Ti 10-2-3, Ti 15-3-3-3, Ti-6-6-2, Ti-185, or any combination thereof), an aluminum alloy, or a composite material. In other embodiments, strikeface 2212 can comprise carpenter grade 455 steel, carpenter grade 475 steel, C300 steel, C350 steel, a Ni-Co-Cr steel alloy, a quench and tempered steel alloy, or 565 steel. In some embodiments, body 2201 can comprise the same material as strikeface 2212. In some embodiments, body 2201 can comprise a different material than strikeface 2212.

[0049] In many embodiments, a cavity 2230 is located below top rail 2215. In some embodiments, the length of top rail 2215, measured from heel region 2202 to toe region 2204, can be approximately 70% to approximately 95% of the length of golf club head 2200. In many embodiments, cavity 2230 comprises a top rail box spring design. In many embodiments, top rail 2215 and cavity 2230 provide an increase in the overall bending of strikeface 2212. In some embodiments, the bending of strikeface 2212 can allow for an approximately 2% to approximately 5% increase of energy. The cavity 2230 allows for the strikeface 2212 to be thinner and allow additional overall bending. For some fairway wood-type golf club head embodiments, cavity 2230 can be a reverse scoop or indentation of rear 2210 with body 2201 comprising a greater thickness or width sole 2206.

[0050] FIG. 10 illustrates a cross-section of golf club head 2200 along the cross-sectional line XXIV-XXIV in FIG. 8, according to one embodiment. As seen in FIG. 10, strikeface 2212 comprises a high region 2476, a middle region 2474, and a low region 2472. In many embodiments, upper region 2211 of rear 2210 comprises a rear wall 2423, a top wall 2417 of cavity 2230 below and adjacent to rear wall 2423, and a back wall 2219 of cavity 2230 below and adjacent to top wall 2417. In some embodiments, a top wall length 2491 of top wall 2417 can be approximately 0.229 cm (0.090 inch) to approximately 0.330 cm (0.130 inch). In some embodiments, top wall length 2491 of top wall 2417 can be approximately 0.229 cm (0.090 inch), 0.254 cm (0.100 inch), 0.279 cm (0.110 inch), 0.305 cm (0.120 inch), or 0.330 cm (0.130 inch).

[0051] In some embodiments, a height 2480 of rear wall 2423 of the upper region 2211 of rear 2210 can be approximately 0.318 cm (0.125 inch) to approximately 1.91 cm (0.75 inch), or approximately 0.381 cm (0.150 inch) to approximately 1.02 cm (0.400 inch). For example, in some embodiments, the height 2480 of rear wall 2423 of the upper region 2211 of rear 2210 can be approximately 0.445 cm (0.175 inch), 0.699 cm (0.275 inch), 0.953 cm (0.375 inch), 1.21 cm (0.475 inch), 1.46 cm (0.575 inch), or 1.71 cm (0.675 inch). In some embodiments, the height 2480 of rear wall 2423 of the upper region 2211 of rear 2210 can be approximately 0.4572 cm (0.180 inch) to approximately 0.508 cm (0.200 inch). In some embodiments, the height 2480 of rear wall 2423 of the upper region 2211 of rear 2210 can be approximately 0.4826 cm (0.190 inch). In some embodiments, the height 2480 of rear wall 2423 of the upper region 2211 of rear 2210 can be approximately 5% to approximately 25% of the height of golf club head 2200.

[0052] The height 2480 of rear wall 2423 of the upper region 2211 of rear 2210, as described herein, allows cavity 2230 to absorb at least a portion of the stress on strikeface 2212 during impact with a golf ball. A golf club head having a rear wall height greater than rear wall height 2480 described herein would absorb less stress (and allow less strikeface deflection) on impact than the golf club head 2200 described herein, due to increased dispersion of the impact stress along the top rail prior to reaching the cavity.

[0053] In some embodiments, cavity 2230 is located above a lower region 2213 of rear 2210 and is defined at least in part by upper region 2211 and lower region 2213 of rear 2210. Cavity 2230 comprises the top wall 2417, the back wall 2219, and a bottom incline 2421. A first inflection point 2482 is located between top wall 2417 of cavity 2230 and rear wall 2219 of cavity. A second inflection point 2486 is located between rear wall 2219 of cavity 2230 and bottom incline 2421.

[0054] In some embodiments, a height 2488 of back wall 2219, measured from first inflection point 2482 to second inflection point 2486, can be approximately 0.254 cm (0.100 inch) to approximately 1.524 cm (0.600 inch). For example, height 2488 of back wall 2219 can be approximately 0.254 cm (0.100 inch), 0.381 cm (0.150 inch), 0.508 cm (0.200 inch), 0.635 cm (0.250 inch), 0.762 cm (0.300 inch), 0.889 cm (0.350 inch), 1.016 cm (0.400 inch), 1.143 cm (0.450 inch), 1.27 cm (0.500 inch), 1.397 cm (0.550 inch), or 1.524 cm (0.600 inch). In many embodiments, height 2488 of back wall 2219 can be approximately 1.067 cm (0.420 inch) to approximately 1.321 cm (0.520 inch). In some embodiments, height 2488 of back wall 2219 can be approximately 1.067 cm (0.420 inch), 01.092 cm (0.430 inch), 1.118 cm (0.440 inch), 1.143 cm (0.450 inch), 1.168 cm (0.460 inch), 1.194 cm (0.470 inch), 1.219 cm (0.480 inch), 1.245 cm (0.490 inch), 1.27 cm (0.500 inch), 1.295 cm (0.510 inch), or 1.321 cm (0.520 inch).

[0055] In many embodiments, an apex of top wall 2417 can be approximately 0.125 cm (0.318 inch) to approximately 1.25 cm (3.18 inches) or approximately 0.25 cm (0.635 inch) to approximately 1.25 cm (3.18 inches) below an apex of top rail 2215. For example, the apex of top wall 2417 can be approximately 0.125 cm (0.318 inch), 0.25 cm (0.635 inch), 0.375 cm (0.953 inch), 0.5 cm (1.27 inch), 0.625 cm (1.59 inch), 0.75 cm (1.91 inch), 0.825 cm (2.10 inch), 1.0 cm (2.54 inch), 1.125 cm (2.88 inch), or 1.25 cm (3.18 inch) below the apex of top rail 2215.

[0056] In many embodiments, back wall 2219 of cavity 2230 can be substantially parallel to strikeface 2212. In other embodiments, back wall 2219 is not substantially parallel to strikeface 2212. In some embodiments, back wall 2219 of cavity 2230 is substantially parallel to rear wall 2423 of upper region 2211 of rear 2210. In many embodiments, back wall 2219 of cavity 2230 is angled away from strikeface 2212 when moving from first inflection point 2482 to second inflection point 2486. This orientation of back wall 2219 creates a buckling point or hinge point or plastic hinge to direct the stress of impact toward cavity 2230 and to allow increased flexing of strikeface 2212 during impact.

[0057] Lower region 2213 of rear 2210 comprises the bottom incline 2421 of cavity 2230 and a lower exterior wall 2427. In some embodiments, bottom incline 2421 of cavity 2230 can have a bottom incline length 2484 measured from second inflection point 2486 to a third inflection point 2492 positioned between bottom incline 2421 and lower exterior wall 2427. In a number of embodiments, bottom incline length 2484 can be approximately 0.150 cm (0.381 inch) to approximately 0.210 cm (0.533 inch). In many embodiments, bottom incline length 2484 can be approximately 0.150 cm (0.381 inch), 0.160 cm (0.406 inch), 0.170 cm (0.432 inch), 0.180 cm (0.457 inch), 0.190 cm (0.483 inch), 0.200 cm (0.508 inch), or 0.210 cm (0.533 inch).

[0058] In some embodiments, a lower angle 2451 can be measured from the between the bottom incline 2421 and the lower exterior wall 2427. In some embodiments, lower angle 2451 can be less than 180 degrees. In a number of embodiments, lower angle 2451 can be approximately 30 degrees to less than 180 degrees. In various embodiments, lower angle 2451 can be approximately 70 degrees to approximately 130 degrees. In some embodiments, lower angle 2451 can be approximately 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, or 130 degrees.

[0059] In some embodiments, an inflection angle 2496 measured from back wall 2219 to bottom incline 2421 can be approximately 70 degrees to approximately 150 degrees. In some embodiments, inflection angle 2496 can be approximately 90 degrees to approximately 130 degrees. In some embodiments, inflection angle 2496 is approximately 70, 75, 80, 85, 90, 95, 100, 110, 115, 120, 125, 130, 135, 140, 145, or 150 degrees.

[0060] In many embodiments, second inflection point 2486, adjacent to bottom incline 2421, can be at least approximately 0.635 cm (0.25 inch) to approximately 5.08 cm (2.0 inches), or approximately 1.27 cm (0.5 inch) to approximately 3.81 cm (1.5 inches) below the apex of top rail 2215. For example, the second inflection point 2486 can be at least approximately 0.635 cm (0.25 inch), 1.27 cm (0.5 inch), 1.91 cm (0.75 inch), 2.53 cm (1.0 inch), 3.18 cm (1.25 inches), 3.81 cm (1.5 inches), 4.45 cm (1.75 inches) or 5.08 cm (2.0 inches) below the apex of top rail 2215. In some embodiments, the maximum height of the bottom incline, measured from the sole 2206 of the club head 2200 to second inflection point 2486, can be at least approximately 0.635 cm (0.25 inch) to approximately 7.62 cm (3 inches), or approximately 1.27 cm (0.50 inch) to approximately 5.08 cm (2 inches) above a lowest point of the sole 2206. For example, the second inflection point 2486 can be at least approximately 0.635 cm (0.25 inch), 0.953 cm (0.375 inch), 1.27 cm (0.5 inch), 1.59 cm (0.625 inch), 1.91 cm (0.75 inch), 2.10 cm (0.825 inch), 2.54 cm (1.0 inch), 2.88 cm (1.125 inches), 3.18 cm (1.25 inches), 3.49 cm (1.375 inches), 3.81 cm (1.5 inches), 4.12 cm (1.625 inches), 4.45 cm (1.75 inches), 4.76 cm (1.875 inches), 5.08 cm (2.0 inches), 5.40 cm (2.125 inches), 5.71 cm (2.25 inches), 6.03 cm (2.375 inches), 6.35 cm (2.5 inches), 6.67 cm (2.625 inches), 7.00 cm (2.75 inches), 7.30 cm (2.875 inches), or 7.62 cm (3.0 inches) above a lowest point of the sole.

[0061] Cavity 2230 further comprises at least one channel 2239 (FIG. 8). In many embodiments, channel 2239 extends from heel region 2202 to toe region 2204. A channel width 2432 (FIG. 10) measured from back wall 2219 (FIG. 10) to rear wall 2423 (FIG. 10) and substantially perpendicular to a ground plane when golf club head 2200 is at address, can be substantially constant throughout channel 2239. In some embodiments, channel width 2432 (FIG. 10) can be approximately 0.2 mm (0.008 inch) to approximately 25 mm (1 inch), or approximately 0.2 mm (0.008 inch) to approximately 8 mm (0.31 inch). For example, channel width 2432 can be approximately 0.2 mm (0.008 inch), 0.4 mm (0.016 inch), 0.6 mm (0.024 inch), 0.8 mm (0.031 inch), 1.0 mm (0.039 inch), 2 mm (0.079 inch), 3 mm (0.12 inch), 4 mm (0.16 inch), 5 mm (0.20 inch), 6 mm (0.24 inch), 7 mm (0.28 inch), 8 mm (0.31 inch), 10 mm (0.39 inch), 15 mm (0.59 inch), 20 mm (0.79 inch), or 25 mm (0.98 inch). In other embodiments, a channel toe region width of channel 2239 is smaller than a channel heel region width of channel. In other embodiments, the channel heel region width is smaller than the channel toe region width. In other embodiments, a channel middle region width of channel 2239 can be smaller than at least one of the channel heel region width or the channel toe region width. In other embodiments, the channel middle region width can be greater than at least one of the channel heel region width or the channel toe region width. In some embodiments, channel 2239 is symmetrical from heel region 2202 to toe region 2204. In other embodiments, channel 2239 is non-symmetrical. In other embodiments, channel 2239 can further comprise at least two partial channels. In some embodiments, channel 2239 can comprise a series of partial channels interrupted by one or more bridges. In some embodiments, the one or more bridges can be approximately the same thickness as the thickness of upper region 2211 of rear 2210.

[0062] The channel width 2432, as described herein, allows absorption of stress from strikeface 2212 on impact. A golf club head having a channel width less than the channel width described herein (e.g. a golf club head with a less pronounced cavity) would allow less stress absorption from the strikeface on impact (due to less material on the upper region 2211 of rear 2210), and therefore would experience less strikeface deflection than the golf club head 2200 described herein.

[0063] In many embodiments, cavity 2230 further comprises a back cavity angle 2435. Back cavity angle is measured between top wall 2417 and back wall 2219 of cavity 2230. In many embodiments, back cavity angle 2435 can be approximately 70 degrees to approximately 110 degrees. In some embodiments, back cavity angle 2435 can be approximately 80 degrees to approximately 100 degrees. In some embodiments, back cavity angle 2435 is approximately 70, 75, 80, 85, 90, 95, 100, or 110 degrees. In many embodiments, back cavity angle 2435 provides a buckling point or plastic hinge or targeted hinge at a top rail hinge point 2470, upon golf club head 2200 impacting the golf ball at strike face 2212. In some embodiments, the wall thickness at top rail hinge point 2470 is thinner than at top wall 2417 of cavity 2230

[0064] FIG. 11 illustrates a view of top rail 2215 and a portion of rear 2210 of the cross-section of golf club head 2200 of FIG. 8 different from cross-section of golf club head 1200 as shown in FIG. 4. In many embodiments, golf club head 2200 comprises a rear angle 2540, a top rail angle 2545, and a strikeface angle 2550. Rear angle 2540 is measured from top wall 2417 to rear wall 2423 of upper region 2211. In many embodiments, rear angle 2540 can be approximately 70 degrees to approximately 110 degrees. In some embodiments, rear angle 2540 is approximately 70, 75, 80, 85, 90, 95, 100, 105, or 110 degrees. Top rail angle 2545 is measured from rear wall 2423 of upper region 2211 to top rail 2215. In many embodiments, top rail angle 2545 can be approximately 35 degrees to approximately 120 degrees or 70 degrees to approximately 110 degrees. In some embodiments, top rail angle 2545 can be approximately 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, or 120 degrees. Strikeface angle 2550 is measured from strikeface 2212 to top rail 2215. In many embodiments, strikeface angle 2550 can be approximately 70 degrees to approximately 160 degrees or 70 degrees to approximately 110 degrees. In some embodiments, strikeface angle 2550 is approximately 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 155, or 160 degrees.

[0065] In some embodiments, a minimum gap 2590 measured perpendicularly to the strikeface 2212 to the back wall 2219 is approximately 2 mm (0.079 inch) to approximately 10 mm (0.39 inch). For example, the minimum gap 2590 between strikeface 2212 and back wall 2219 can be approximately 2 mm (0.079 inch), 4 mm (0.16 inch), 6 mm (0.24 inch), 8 mm (0.31 inch), or 10 mm (0.39 inch). In some embodiments, the minimum gap 2590 between the strikeface 2212 and back wall 2219 is less than approximately 14 mm (0.55 inch), less than approximately 12 mm (0.47 inch), less than approximately 10 mm (0.39 inch), less than approximately 8 mm (0.31 inch), less than approximately 6 mm (0.24 inch), or less than approximately 4 mm (0.16 inch). Further, in some embodiments, a maximum gap between strikeface 2212 and rear wall 2423 of upper region 2211 of golf club head 2200 is greater than minimum gap 2590. Further still, in some embodiments, a maximum gap between strikeface 2212 and bottom incline 2421 (FIG. 10) in lower region 2213 (FIG. 10) of golf club head 2200 is greater than minimum gap 2590 and the maximum gap in upper region 2211.

[0066] FIG. 12 illustrates a simplified cross-sectional view of golf club head 2200, similar to the detailed cross-section of the golf club head 2200 illustrated in FIG. 10. Golf club head 2200 includes the cavity 2230, an exterior surface 2225, the upper region 2211, and the lower region 2213. Upper region 2211 includes rear wall 2423, cavity 2230 includes cavity exterior wall 2225, top wall 2417, and back wall 221, while the lower region 2213 includes bottom incline 2421 and lower exterior wall 2427. In many embodiments, a maximum upper distance 2692 measured as the perpendicular distance from the exterior surface 2225 of the strikeface 2212 to the exterior surface 2225 of the rear wall 2423 of upper region 2211 can be approximately 5-15 mm (0.20-0.59 inch). For example, maximum upper distance 2692 can be approximately 5 mm (0.20 inch), 6 mm (0.24 inch), 7 mm (0.28 inch), 8 mm (0.31 inch), 8.89 mm (0.35 inch), 10 mm (0.39 inch), 11 mm (0.43 inch), 12 mm (0.47 inch), 13 mm (0.51 inch), 14 mm (0.55 inch), or 15 mm (0.59 inch). In some embodiments, maximum upper distance 2692 can be approximately 9.02 mm (0.355 inch).

[0067] Further, a minimum upper distance 2694 measured as the perpendicular distance from the exterior surface 2225 of the strikeface 2212 to the exterior surface 2225 of the back wall 2219 can be approximately 4-12 mm (0.16-0.47 inch). For example, minimum upper distance 2694 can be approximately 4 mm (0.16 inch), 5 mm (0.20 inch), 6 mm (0.24 inch), 7 mm (0.28 inch), 8 mm (0.31 inch), 9 mm (0.35 inch), 10 mm (0.39 inch), 11 mm (0.43 inch), or 12 mm (0.47 inch). In some embodiments, minimum upper distance 2694 can be approximately 7.21 mm (0.284 inch).

[0068] Further still, a maximum lower distance 2696 measured as the perpendicular distance from the exterior surface 2225 of the strikeface 2212 to the exterior surface 2225 of the lower exterior wall 2427 can be approximately 25 mm (0.98 inch) to 40 mm (1.57 inch). For example, maximum lower distance 2696 can be approximately 25 mm (0.98 inch), 26 mm (1.02 inch), 27 mm (1.06 inch), 28 mm (1.10 inch), 29 mm (1.14 inch), 30 mm (1.18 inch), 31 mm (1.22 inch), 32 mm (1.26 inch), 33 mm (1.30 inch), 34 mm (1.34 inch), 35 mm (1.38 inch), 36 mm (1.42 inch), 37 mm (1.46 inch), 38 mm (1.50 inch), 39 mm (1.54 inch), or 40 mm (1.57 inch). In some embodiments, maximum lower distance 2696 can be approximately 26.5 mm (1.043 inch). In many embodiments, maximum lower distance 2696 is greater than maximum upper distance 2692, and maximum upper distance 2692 is greater than minimum upper distance 2694.

[0069] In many embodiments, cavity 2230 can provide an increase in golf ball speed over golf club head 1200 (FIG. 11) or other standard golf club heads, can reduce the spin rate of standard hybrids club heads, and can increase the launch angle over both the standard hybrid and iron club heads. In many embodiments, the shape of cavity 2230 determines the level of spring and timing of the response of golf club head 2200. When the golf ball impacts strikeface 2212 of club head 2200 with cavity 2230, strikeface 2212 springs back like a drum, and rear 2210 bends in a controlled buckle manner. In many embodiments, top rail 2215 can absorb more stress over greater volumetric space than a top rail in a golf club head without cavity 2230. The length, depth and width of cavity 2230 can vary. These parameters provide control regarding how much spring back is present in the overall design of club head 2200.

[0070] Upon impact with the golf ball, strikeface 2212 can bend inward at a greater distance than on a golf club without cavity 2230. In some embodiments, strikeface 2212 has an approximately 10% to approximately 50% greater deflection than a strikeface on a golf club head without cavity 2230. In some embodiments, strikeface 2212 has an approximately 5% to approximately 40% or approximately 10% to approximately 20% greater deflection than a strikeface on a golf club head without cavity 2230. For example, strikeface 2212 can have an approximately 5%, 10%, 15%, 20%, 25%, 30%, 35% or 40% greater deflection than a strikeface on a golf club head without cavity 2230. In many embodiments, there is both a greater distance of retraction by strikeface 2212 due to the hinge and bending of cavity 2230 over a standard strikeface that does not have a back portion of the club without the cavity.

[0071] In many embodiments, the face deflection is greater with club head 2200 having cavity 2230, as a greater buckling occurs along top rail hinge point 2470 upon impact with the golf ball. Cavity 2230, however, provides a greater dispersion of stress along top rail hinge point 2470 region of the top rail, and the spring back force is transferred from cavity 2230 and top rail 2215 to strikeface 2212. A standard top rail without a cavity does not have this hinge/buckling effect, nor does it absorb a high level of stress over a large volumetric area of the top rail. Therefore, the standard strikeface does not contract and then recoil as much as strikeface 2212. Further, both a larger region of strikeface 2212 and top rail 2215 absorb more stress than the same crown region of a standard golf club head with a standard top rail and no cavity. In many embodiments, although there is greater stress along a greater area above cavity 2230 than the same area in a standard club without the cavity, the durability of the club head with and without the cavity is the same. By adding more spring to the back end of the club (due to the inward inclination of top wall 2417 toward strikeface 2212), more force is displaced throughout the volume of the structure. The stress is observed over a greater area of strikeface 2212 and top rail 2215 of golf club head 2200. Peak stresses can be seen in the standard top rail club head. However, more peak stresses are seen in golf club head 2200 but distributed over a large volume of the material. The hinge and bend regions of golf club head 2200 (i.e., the region above cavity 2230 and cavity 2230 itself) will not deform as long as the stress does not meet the critical buckling threshold. Cavity 2230 and its placement can be designed to be under the critical K value of the buckling threshold.

[0072] Turning to FIG. 5, FIG. 5 illustrates a golf club 1500 comprising a golf club head 1500 and a shaft 1590 coupled to golf club head 1500. In some embodiments, golf club head 1500 of golf club 15000 comprises a hybrid-type golf club head. In other embodiments, golf club head 1500 can be an iron-type golf club head or a fairway wood-type golf club head. In many embodiments, golf club head 1500 can be similar to golf club head 100 or golf club head 1000 (FIG. 1). Golf club head 1500 can be hollow-bodied and comprises a strikeface 1512, a heel region 1502, a toe region 1504 opposite heel region 1502, a sole 1506, and a crown 1508. The crown 1508 comprises an upper region 1511 and a lower region 1513. The upper region 1511 comprises a top rail 1515. Golf club head 1500 further comprises a cavity 1530 located below top rail 1515 and above lower region 1513 of crown 1508.

[0073] FIG. 6 illustrates a cross-section of golf club head 1500 along the cross-sectional line XVI-XVI in FIG. 5, according to one embodiment. In some embodiments, cavity 1530 can be defined at least in part by upper region 1511 and lower region 1513. In many embodiments, cavity 1530 comprises a top wall 1517, a back wall 1519, a bottom incline 1521, a back cavity angle 1535 measured between top wall 1517 and back wall 1519, and at least one channel 1539. In some embodiments, an apex of top wall 1517 is approximately 6.35 mm (0.25 inch) to approximately 31.75 mm (1.25 inches) below an apex of top rail 1515. In some embodiments, the apex of top wall 1517 is approximately 9.53 mm (0.375 inch) below the apex of top rail 1515. In some embodiments, bottom incline 1521 can be at least approximately 12.7 mm (0.50 inch) to approximately 50.8 mm (2 inches) below an apex of top rail 1515. In many embodiments, back cavity angle 1535 can be approximately 70 degrees to approximately 110 degrees. In some embodiments, back cavity angle 1535 can be approximately 90 degrees.

[0074] In many embodiments, the upper region 1511 comprises the top and back walls of the cavity; and the lower region of the crown comprises the bottom incline of the cavity. In some embodiments, upper region 1511 further comprises a rear wall 1523 adjacent to top wall 1517 of cavity 1530 and a rear angle 1540 measured between top wall 1517 of cavity 1530 and rear wall 1523 of upper region 1511. In many embodiments, rear angle 1540 is approximately 70 degrees to approximately 110 degrees.

[0075] In another embodiment, the golf club head can comprise a hosel. The hosel can comprise a hosel notch. The hosel notch can allow for iron-like range of loft and lie angle adjustability.

[0076] As shown in FIG. 12, a further deflection feature of the golf club head 2200 can be the uniform thinned region 2660, located at the sole 2206 and stretching between the rear 2210 of the body 2201 and the strikeface 2212, toward a cascading sole portion of the sole (as described in greater detail below). The uniform thinned region 2660 can provide multiple benefits. First, the uniform thinned region 2660 can reduce stress on the strikeface 2212 caused during impact with the golf ball. Second, the uniform thinned region 2660 can bend allowing the strikeface 2212 to experience greater deflection. Third, the uniform thinned region 2660 removes weight from the sole area, allowing the weight to be redistributed more toward the rear of the golf club head 2200. At impact, the energy imparted to the strikeface 2212 by the golf ball can cause the uniform thinned region 2660 to bend outward, which in turn increases the strikeface 2212 deflection. After bending, the uniform thinned region 2660 rebounds back to its original position returning the majority of the energy from impact back to the golf ball. The result is the golf club head 2200 imparts increased ball speeds and greater travel distances to the golf ball after impact.

[0077] Turning ahead in the drawings, FIG. 13 illustrates a back perspective view of an embodiment of golf club head 2700 and FIG. 14 illustrates a back heel-side perspective view of golf club head 2700 according to the embodiment of FIG. 13. In some embodiments, golf club head 2700 can be similar to golf club head 1000 (FIG. 1), and/or golf club head 2200 (FIG. 8). Golf club head 2700 can be a hybrid-type golf club head. In other embodiments, golf club head 2700 can be an iron-type golf club head or a fairway wood-type golf club head. In many embodiments, golf club head 2700 does not include a badge or a custom tuning port.

[0078] Golf club head 2700 comprises a body 2701. In some embodiments, body 2701 can be similar to body 1001 (FIG. 1), and/or body 2201 (FIG. 8). In many embodiments, the body is hollow. In some embodiments, the body is at least partially hollow. Body 2701 comprises an exterior surface 2703, a strikeface 2712, a heel region 2702, a toe region 2704 opposite heel region 2702, a sole 2706, and a rear 2710.

[0079] Body 2701 of FIGS. 13-17 further comprises a blade length. The blade length for body 2701 can be measured similar to blade length 3725 as shown and described in FIG. 43 (i.e., a measurement parallel to the flat surface of the strikeface 3712, from a toe edge 3726 of the strikeface 3712, to strikeface end 3727 right before the strikeface 3712 integrally curves into the hosel). The blade length of the body 2701 can range from (2.80 inch) 7.11 cm to (3.00 inch) 7.62 cm. For example, in some embodiments, the body 2701 can comprise a blade length of (2.80 inch) 7.11 cm, (2.82 inch) 7.16 cm, (2.84 inch) 7.21 cm, (2.86 inch) 7.26 cm, (2.88 inch) 7.32 cm, (2.90 inch) 7.37 cm, (2.93 inch) 7.44 cm, (2.94 inch) 7.47 cm, (2.96 inch) 7.52 cm, (2.98 inch) 7.57 cm, or (3.00 inch) 7.62 cm.

[0080] The body 2701 further comprises a uniform thinned region transitioning from the bottom of the strikeface 2712 to the sole 2706, toward a cascading sole portion of the sole (as described in greater detail below). In the illustrated embodiment, the uniform thinned region comprises a sole thickness measured perpendicular from the exterior surface 2703 to the interior surface at the uniform thinned region, which can remain constant from the bottom of the strikeface 2712 to adjacent the cascading sole portion of the sole. In some embodiments, the sole thickness of the uniform thinned region can be thinner than a conventional sole. For example, in some embodiments, the sole thickness of the uniform thinned region may range from approximately 0.102 cm (0.040 inch) to 0.203 cm (0.080 inch). In other embodiments, the sole thickness of the uniform thinned region may be within the range of 0.102 cm (0.040 inch) to 0.127 cm (0.050 inch), 0.127 cm (0.050 inch) to 0.152 cm (0.060 inch), 0.152 cm (0.060 inch) to 0.178 cm (0.070 inch), 0.178 cm (0.070 inch) to 0.203 cm (0.080 inch), 0.102 cm (0.040 inch) to 0.140 cm (0.055 inch), 0.114 cm (0.045 inch) to 0.152 cm (0.060 inch), 0.127 cm (0.050 inch) to 0.165 cm (0.065 inch), 0.140 cm (0.055 inch) to 0.178 cm (0.070 inch), 0.152 cm (0.060 inch) to 0.191 cm (0.075 inch), or 0.165 cm (0.065 inch) to 0.203 cm (0.080 inch). For example, the sole thickness of the uniformed thinned region can be 0.102 cm (0.040 inch), 0.114 cm (0.045 inch), 0.127 cm (0.050 inch), 0.152 cm (0.060 inch), 0.165 cm (0.065 inch), 0.178 cm (0.070 inch), 0.191 cm (0.075 inch), or 0.203 cm (0.080 inch).

[0081] FIG. 15 illustrates a cross-section of golf club head 2700 along the cross-sectional line XXIX-XXIX in FIG. 13, according to one embodiment. As seen in FIG. 15, strikeface 2712 comprises a high region 2976, a middle region 2974, and a low region 2972. Rear 2710 comprises an upper region 2711 and a lower region 2713 (FIG. 15). Upper region 2711 comprises a top rail 2715, a rear wall 2923, and a top wall 2719. The top rail 2715 can be similar to the top rail 1015 of golf club head 1000. In many embodiments, rear wall 2923 of rear 2710 is located below and adjacent to top rail 2715, and a top wall 2719 of rear 2710 is located below and adjacent to rear wall 2923. Lower region 2713 comprises a back wall 2921, and a lower exterior wall 2927, wherein back wall 2921 is located below an adjacent the top wall 2719, and the lower exterior wall 2927 is located below and adjacent the back wall 2921. Cavity 2730 is located on the exterior surface 2703, below the top rail 2715 and rear wall 2923, above the lower region 2713 of rear 2710, and is defined by at least in part by upper region 2711 and lower region 2713.

[0082] In some embodiments, top rail 2715 of the upper region 2711 of the rear 2710 can be a flatter and taller top rail or skirt than in the in irons known to one skilled in the art. The flatter and taller top rail can compensate for mis-hits on strikeface 2712 to increase playability off the tee. In some embodiments, the length of top rail 2715, measured from heel region 2702 to toe region 2704, can be 70% to 95% of the length of golf club head 2700. In many embodiments, cavity 2730 comprises a top rail box spring design. In many embodiments, top rail 2715 and cavity 2730 provide an increase in the overall bending of strikeface 2712. In some embodiments, the bending of strikeface 2712 can allow for a 2% to 5% increase of energy. Cavity 2730 allows for strikeface 2712 to be thinner and allow additional overall bending. For some fairway wood-type golf club head embodiments, cavity 2730 can be a reverse scoop or indentation of rear 2710 with body 2701 comprising a greater thickness or width toward sole 2706.

[0083] In some embodiments, a height 2980 of rear wall 2923 of the upper region 2711 of rear 2710 can range from 0.318 cm (0.125 inch) to 1.91 cm (0.75 inch), or) 0.381 cm (0.150 inch) to 1.02 cm (0.400 inch). For example, in some embodiments, the height 2980 of rear wall 2923 of the upper region 2711 of rear 2710 can be 0.445 cm (0.175 inch), 0.699 cm (0.275 inch),) 0.953 cm (0.375 inch), 1.21 cm (0.475 inch), 1.46 cm (0.575 inch), or 1.71 cm (0.675 inch). In some embodiments, the height 2980 of rear wall 2923 of the upper region 2711 of rear 2710 can range from 0.381 cm (0.150 inch) to 0.508 cm (0.200 inch). In some embodiments, the height 2980 of rear wall 2923 of the upper region 2711 of rear 2710 can be 0.432 cm (0.170 inch). In some embodiments, the height 2980 of rear wall 2923 of the upper region 2711 of rear 2710 can be 5% to 25% of the height of golf club head 2700.

[0084] The height 2980 of rear wall 2923 of the upper region 2711 of rear 2710, as described herein, allows cavity 2730 to absorb at least a portion of the stress on strikeface 2712 during impact with a golf ball. A golf club head having a rear wall height greater than rear wall height 2980 described herein would absorb less stress (and allow less strikeface deflection) on impact than golf club head 2700 described herein, due to increased dispersion of the impact stress along the top rail prior to reaching the cavity.

[0085] In some embodiments, cavity 2730 is located above a lower region 2713 of rear 2710 and is defined at least in part by upper region 2711 and lower region 2713 of rear 2710. Cavity 2730 comprises top wall 2719, and a back wall 2921. A first reference point 2922 is located between the top rail 2715 and rear wall 2923. A second reference point 2982 is located between rear wall 2923 and top wall 2719. A first inflection point 2986 is located between top wall 2719 of cavity 2730 and back wall 2921. A third reference point 2924 is a point located on top wall 2719 closest to the strikeface 2712. First reference point 2922 and second reference point 2982 create a first reference line 2929. Second reference point 2982 and third reference point 2924 create a second reference line 2925. Third reference point 2924 and first inflection point 2986 create a third reference line 2926.

[0086] Golf club head 2700 further comprises a height 2988 of top wall 2719, measured parallel to strikeface 2712 and from the second reference point 2982 to first inflection point 2986. In many embodiments, height 2988 can range from 0.254 cm (0.100 inch) to 1.524 cm (0.600 inch). For example, height 2988 can be 0.254 cm (0.100 inch), 0.381 cm (0.150 inch), 0.508 cm (0.200 inch), 0.635 cm (0.250 inch), 0.762 cm (0.300 inch), 0.889 cm (0.350 inch), 1.016 cm (0.400 inch), 1.143 cm (0.450 inch), 1.27 cm (0.500 inch), 1.397 cm (0.550 inch), or 1.524 cm (0.600 inch). In many embodiments, height 2988 can range from 1.27 cm (0.500 inch) to 1.524 cm (0.600 inch). In some embodiments, height 2488 of top wall 2719 can be 1.27 cm (0.500 inch), 1.295 cm (0.510 inch), 1.321 cm (0.520 inch), 1.346 cm (0.530 inch), 1.372 cm (0.540 inch), 1.397 cm (0.550 inch), 1.422 cm (0.560 inch), 1.448 cm (0.570 inch), 1.473 cm (0.580 inch), 1.499 cm (0.590 inch), or 1.524 cm (0.600 inch).

[0087] In many embodiments, second reference point 2982 can be 0.318 cm (0.125 inch) to 3.18 cm (1.25 inches) or 0.635 cm (0.25 inch) to 3.18 cm (1.25 inches) to apex 2928 of top rail 2715. For example, the second reference point 2982 can be 0.318 cm (0.125 inch), 0.635 cm (0.25 inch), 0.953 cm (0.375 inch), 1.27 cm (0.5 inch), 1.59 cm (0.625 inch), 1.91 cm (0.75 inch), 2.10 cm (0.825 inch), 2.54 cm (1.0 inch), 2.88 cm (1.125 inches), or 3.18 cm (1.25 inches) below the apex 2928 of top rail 2715.

[0088] In many embodiments, top wall 2719 of cavity 2730 can be substantially parallel to strikeface 2712. In other embodiments, top wall 2719 is not substantially parallel to strikeface 2712. In some embodiments, top wall 2719 of cavity 2730 is substantially parallel to rear wall 2923 of upper region 2711 of rear 2710. In a number of embodiments, a portion of top wall 2719 extends away from rear wall 2923 toward strikeface 2712 from second reference point 2982 to third reference point 2924. In some embodiments, the portion of top wall 2719 extending away from rear wall 2923 toward strikeface 2712 from second reference point 2982 to third reference point 2924 can be straight, curved upward, or curved downward. In many embodiments, a portion of top wall 2719 of cavity 2730 is angled away from strikeface 2712 from third reference point 2924 to first inflection point 2986. In some embodiments, the portion of top wall 2719 angled away from strikeface 2712 from third reference point 2924 to first inflection point 2986 can be straight, curved upward, or curved downward. This orientation of top wall 2719 creates a buckling point, hinge point or plastic hinge to direct the stress of impact toward cavity 2730 and to allow increased flexing of strikeface 2712 during impact.

[0089] Lower region 2713 of rear 2710 comprises back wall 2921 of cavity 2730 and the lower exterior wall 2927. In some embodiments, back wall 2921 of cavity 2730 can have a back wall length 2990 measured from first inflection point 2986 to a second inflection point 2992 located between the back wall 2921, and the lower exterior wall 2927. In a number of embodiments, back wall length 2990 can range from 0.381 cm (0.150 inch) to 1.02 cm (0.400 inch). In many embodiments, back wall length 2990 can be 0.406 cm (0.160 inch), 0.432 cm (0.170 inch), 0.457 cm (0.180 inch), 0.483 cm (0.190 inch), 0.508 cm (0.200 inch), 0.533 cm (0.210 inch), 0.559 cm (0.220 inch), 0.584 cm (0.230 inch), 0.61 cm (0.240 inch), 0.635 cm (0.250 inch), 0.660 cm (0.260 inch), 0.686 cm (0.270 inch), 0.711 cm (0.280 inch), 0.737 cm (0.290 inch), 0.762 cm (0.300 inch), 0.787 cm (0.310 inch), 0.813 cm (0.320 inch), 0.838 cm (0.330 inch), 0.864 cm (0.340 inch), 0.889 cm (0.350 inch), 0.914 cm (0.360 inch), 0.94 cm (0.370 inch), 0.965 cm (0.380 inch), 0.991 cm (0.390 inch), or 1.02 cm (0.400 inch).

[0090] In some embodiments, a lower angle 2951 can be measured from between the back wall 2921 and the lower exterior wall 2927. In some embodiments, lower angle 2951 can be less than 180 degrees. In a number of embodiments, lower angle 2951 can range from 30 degrees to 180 degrees. In various embodiments, lower angle 2951 can range from70 degrees to 130 degrees. In some embodiments, lower angle 2951 can be 70 degrees, 75 degrees, 80 degrees, 85 degrees, 90 degrees, 95 degrees, 100 degrees, 105 degrees, 110 degrees, 115 degrees, 120 degrees, 125 degrees, or 130 degrees.

[0091] In some embodiments, an inflection angle 2996 measured from third reference line 2926 to back wall 2921 can range from 70 degrees to 150 degrees. In some embodiments, inflection angle 2996 can range from 90 degrees to 130 degrees. In some embodiments, inflection angle 2996 can be 70 degrees, 75 degrees, 80 degrees, 85 degrees, 90 degrees, 95 degrees, 100 degrees, 105 degrees, 110 degrees, 115 degrees, 120 degrees, 125 degrees, 130 degrees, 135 degrees, 140 degrees, 145 degrees, or 150 degrees. In many embodiments, inflection angle 2996 allows first inflection point 2986 to act as a buckling point or plastic hinge upon golf club head 2700 impacting the golf ball at strike face 2712. In some embodiments, the wall thickness at the first inflection point 2986 can be thinner than at the top wall 2719 and back wall 2921.

[0092] In many embodiments, first inflection point 2986, adjacent to back wall 2921, can range from 0.635 cm (0.25 inch) to 5.08 cm (2.0 inches), or 1.27 cm (0.5 inch) to 3.81 cm (1.5 inches) below the apex 2928 of top rail 2715. For example, the first inflection point 2986 can be 0.635 cm (0.25 inch), 1.27 cm (0.5 inch), 1.91 cm (0.75 inch), 2.53 cm (1.0 inch), 3.18 cm (1.25 inches), 3.81 cm (1.5 inches), 4.45 cm (1.75 inches) or 5.08 cm (2.0 inches) below the apex 2928 of top rail 2715. In some embodiments, the maximum height of the back wall 2921, measured perpendicular to a ground plane 2903 when golf club head 2700 is at address from a lowest point of sole 2706 to first inflection point 2986, can range from 0.635 cm (0.25 inch) to 7.62 cm (3 inches), or 1.27 cm (0.50 inch) to 5.08 cm (2 inches). For example, the first inflection point 2986 can be 0.635 cm (0.25 inch), 0.953 cm (0.375 inch), 1.27 cm (0.5 inch), 1.59 cm (0.625 inch), 1.91 cm (0.75 inch), 2.10 cm (0.825 inch), 2.54 cm (1.0 inch), 2.88 cm (1.125 inches), 3.18 cm (1.25 inches), 3.49 cm (1.375 inches), 3.81 cm (1.5 inches), 4.12 cm (1.625 inches), 4.45 cm (1.75 inches), 4.76 cm (1.875 inches), 5.08 cm (2.0 inches), 5.40 cm (2.125 inches), 5.71 cm (2.25 inches), 6.03 cm (2.375 inches), 6.35 cm (2.5 inches), 6.67 cm (2.625 inches), 7.00 cm (2.75 inches), 7.30 cm (2.875 inches), or 7.62 cm (3.0 inches) above a lowest point of sole 2706 perpendicular to the ground plane 2903 when golf club head 2700 is at address.

[0093] In some embodiments, a back wall angle 2905 measured from back wall 2921 to ground plane 2903 can range from 15 degrees to 45 degrees. In some embodiments, back wall angle 2905 can be 15 degrees, 16 degrees, 17 degrees, 18 degrees, 19 degrees, 20 degrees, 21 degrees, 22 degrees, 23 degrees, 24 degrees, 25 degrees, 26 degrees, 27 degrees, 28 degrees, 29 degrees 30 degrees, 31 degrees, 32 degrees, 33 degrees, 34 degrees, 35 degrees, 36 degrees, 37 degrees, 38 degrees, 39 degrees, 40 degrees, 41 degrees, 42 degrees, 43 degrees, 44 degrees, or 45 degrees.

[0094] In some embodiments, cavity 2730 can further comprise at least one channel 2739 (FIG. 13). In many embodiments, channel 2739 extends from heel region 2702 (FIG. 13) to toe region 2704 (FIG. 13). Channel 2739 comprises a channel width measured from second reference point 2982 to top wall 2719 substantially parallel to ground plane 2903, where channel width can vary in a direction from top rail 2715 to sole 2706. In some embodiments, a maximum channel width 2932, measured from first inflection point 2986 to second reference point 2982 substantially parallel to ground plane 2903, can be substantially constant throughout channel 2739 from heel region 2702 to toe region 2704. In some embodiments, maximum channel width 2932 (FIG. 15) can range from 0.2 mm (0.008 inch) to 25 mm (1 inch), or 0.2 mm (0.008 inch) to 8 mm (0.31 inch). For example, maximum channel width 2932 can be 0.2 mm (0.008 inch), 0.4 mm (0.016 inch), 0.6 mm (0.024 inch), 0.8 mm (0.031 inch), 1.0 mm (0.039 inch), 2 mm (0.079 inch), 3 mm (0.12 inch), 4 mm (0.16 inch), 5 mm (0.20 inch), 6 mm (0.24 inch), 7 mm (0.28 inch), 8 mm (0.31 inch), 10 mm (0.39 inch), 15 mm (0.59 inch), 20 mm (0.79 inch), or 25 mm (0.98 inch). In other embodiments, a channel toe region width of channel 2739 is less than a channel heel region width of channel 2739. In other embodiments, the channel heel region width is less than the channel toe region width. In other embodiments, a channel middle region width of channel 2739 can be less than at least one of the channel heel region width or the channel toe region width. In other embodiments, the channel middle region width can be greater than at least one of the channel heel region width or the channel toe region width. In some embodiments, channel 2739 is symmetrical from heel to toe. In other embodiments, channel 2739 is non-symmetrical. In other embodiments, channel 2739 can further comprise at least two partial channels. In some embodiments, channel 2739 can comprise a series of partial channels interrupted by one or more bridges. In some embodiments, the one or more bridges can be approximately the same thickness as the thickness of top rail 2715.

[0095] Maximum channel width 2932, as described herein, allows absorption of stress from strikeface 2712 on impact. A golf club head having a channel width less than the maximum channel width described herein (e.g. a golf club head with a less pronounced cavity) would allow less stress absorption from the strikeface on impact (due to less material on the upper region 2711 of rear 2710), and therefore would experience less strikeface deflection than golf club head 2700 described herein.

[0096] In many embodiments, cavity 2730 further comprises a back cavity angle 2935. Back cavity angle 2935 is measured from first reference line 2929 to second reference line 2925. In many embodiments, back cavity angle 2935 can range from 15 degrees to 80 degrees. In some embodiments, back cavity angle 2935 is 15 degrees, 20 degrees, 25 degrees, 30 degrees, 35 degrees, 40 degrees, 45 degrees, 50 degrees, 55 degrees, 60 degrees, 65 degrees, 70 degrees, 75 degrees or 80 degrees.

[0097] FIG. 16 illustrates a view of top rail 2715 and a portion of rear 2710 of the cross-section of golf club head 2700 of FIG. 13 different from cross-section of golf club head 1200 as shown in FIG. 4. In many embodiments, golf club head 2700 comprises a rear angle 3040, a top rail angle 3045, and a strikeface angle 3050. Rear angle 3040 is measured from second reference line 2925 to rear wall 2923 of upper region 2711. In many embodiments, rear angle 3040 can range from 70 degrees to 140 degrees. In some embodiments, rear angle 3040 can be 70 degrees, 75 degrees, 80 degrees, 85 degrees, 90 degrees, 95 degrees, 100 degrees, 105 degrees, 110 degrees, 115 degrees, 120 degrees, 125 degrees, 130 degrees, 135 degrees, or 140 degrees. Top rail angle 3045 is measured from rear wall 2923 of upper region 2711 to top rail 2715. In many embodiments, top rail angle 3045 can range from 35 degrees to 120 degrees or 70 degrees to 110 degrees. In some embodiments, top rail angle 3045 can be 35 degrees, 40 degrees, 45 degrees, 50 degrees, 55 degrees, 60 degrees, 65 degrees, 70 degrees, 75 degrees, 80 degrees, 85 degrees, 90 degrees, 95 degrees, 100 degrees, 105 degrees, 110 degrees, 115 degrees, or 120 degrees. Strikeface angle 3050 is measured from strikeface 2712 to top rail 2715. In many embodiments, strikeface angle 3050 can range from 70 degrees to 160 degrees or 70 degrees to 110 degrees. In some embodiments, strikeface angle 3050 can be 70 degrees, 75 degrees, 80 degrees, 85 degrees, 90 degrees, 95 degrees, 100 degrees, 105 degrees, 110 degrees, 115 degrees, 120 degrees, 125 degrees, 130 degrees, 135 degrees, 140 degrees, 145 degrees, 150 degrees, 155 degrees, or 160 degrees.

[0098] Upper region 2711 further comprises a minimum gap 3090 measured from third reference point 2924 of an inner surface 2919 of top wall 2719 to an inner surface 2919 of strikeface 2712, perpendicular to strikeface 2712. In some embodiments, minimum gap 3090 can range from 2 mm (0.079 inch) to 10 mm (0.39 inch). For example, the minimum gap 3090 can be 2 mm (0.079 inch), 4 mm (0.16 inch), 6 mm (0.24 inch), 8 mm (0.31 inch), or 10 mm (0.39 inch). In other embodiments, the minimum gap 3090 can range from 4 mm (0.16 inch) to 14 mm (0.55 inch). In some embodiments, the minimum gap 3090 can be 14 mm (0.55 inch), 12 mm (0.47 inch), 10 mm (0.39 inch), 8 mm (0.31 inch), 6 mm (0.24 inch), or 4 mm (0.16 inch).

[0099] FIG. 17 illustrates a simplified cross-sectional view of golf club head 2700, similar to the detailed cross-section of golf club head 2700 illustrated in FIG. 15. Golf club head 2700 includes cavity 2730, upper region 2711, lower region 2713, and exterior surface 2703. In many embodiments, a maximum upper distance 3192 measured as the perpendicular distance from exterior surface 2703 of strikeface 2712 to exterior surface 2703 of second reference point 2982 of upper region 2711 can range from 5 mm (0.20 inch) to 15 mm (0.59 inch). For example, maximum upper distance 3192 can be 5 mm (0.20 inch), 6 mm (0.24 inch), 7 mm (0.28 inch), 8 mm (0.31 inch), 8.89 mm (0.35 inch), 10 mm (0.39 inch), 11 mm (0.43 inch), 12 mm (0.47 inch), 13 mm (0.51 inch), 14 mm (0.55 inch), or 15 mm (0.59 inch). In some embodiments, maximum upper distance 3192 can be 9.09 mm (0.358 inch). Further, a minimum upper distance 3194 measured as the perpendicular distance from exterior surface 2703 of strikeface 2712 to exterior surface 2703 of third inflection point 2924 can range from 2.28 mm (0.09 inch) to 12 mm (0.47 inch). For example, minimum upper distance 3194 can be 4 mm (0.16 inch), 5 mm (0.20 inch), 6 mm (0.24 inch), 7 mm (0.28 inch), 8 mm (0.31 inch), 9 mm (0.35 inch), 10 mm (0.39 inch), 11 mm (0.43 inch), or 12 mm (0.47 inch). In some embodiments, minimum upper distance 3194 can be 7.85 mm (0.309 inch). Further still, a maximum lower distance 3196 measured as the perpendicular distance from exterior surface 2703 of strikeface 2712 to exterior surface 2703 of a fourth reference point 2920 located between the lower exterior wall 2927 and the sole 2706 can range from 25 mm (0.98 inch) to 40 mm (1.57 inch). For example, maximum lower distance 3196 can be 25 mm (0.98 inch), 26 mm (1.02 inch), 27 mm (1.06 inch), 28 mm (1.10 inch), 29 mm (1.14 inch), 30 mm (1.18 inch), 31 mm (1.22 inch), 32 mm (1.26 inch), 33 mm (1.30 inch), 34 mm (1.34 inch), 35 mm (1.38 inch), 36 mm (1.42 inch), 37 mm (1.46 inch), 38 mm (1.50 inch), 39 mm (1.54 inch), or 40 mm (1.57 inch). In some embodiments, maximum lower distance 3196 can be 33.1 mm (1.302 inch). In many embodiments, maximum lower distance 3196 is greater than maximum upper distance 3192, and maximum upper distance 3192 is greater than minimum upper distance 3194.

[0100] In many embodiments, cavity 2730 can provide an increase in golf ball speed over golf club head 1200 (FIG. 16) or other standard golf club heads, can reduce the spin rate of standard hybrids club heads, and can increase the launch angle over both the standard hybrid and iron club heads. In many embodiments, the shape of cavity 2730 determines the level of spring and timing of the response of golf club head 2700. When the golf ball impacts strikeface 2712 of club head 2700 with cavity 2730, strikeface 2712 springs back like a drum, and rear 2710 bends in a controlled buckle manner. In many embodiments, top rail 2715 can absorb more stress over greater volumetric space than a top rail in a golf club head without cavity 2730. The length, depth and width of cavity 2730 can vary. These parameters provide control regarding how much spring back is present in the overall design of club head 2700.

[0101] Upon impact with the golf ball, strikeface 2712 can bend inward at a greater distance than on a golf club without cavity 2730. In some embodiments, strikeface 2712 has a 10% to a 50% greater deflection than a strikeface on a golf club head without cavity 2730. In some embodiments, strikeface 2712 has a 5% to a 40% or a 10% to a 20% greater deflection than a strikeface on a golf club head without cavity 2730. For example, strikeface 2712 can have a 5%, 10%, 15%, 20%, 25%, 30%, 35% or 40% greater deflection than a strikeface on a golf club head without cavity 2730. In many embodiments, there is both a greater distance of retraction by strikeface 2712 due to the hinge and bending of cavity 2730 over a standard strikeface that does not have a back portion of the club without the cavity.

[0102] In many embodiments, the face deflection is greater with club head 2700 having cavity 2730, as a greater buckling occurs at first inflection angle 2986 of top wall 2719 upon impact with a golf ball. Cavity 2730, however, provides a greater dispersion of stress along top rail 2715, rear wall 2923, and top wall 2719, and the spring back force is transferred from cavity 2730 and first inflection point 2986 of top wall 2719 to strikeface 2712. A standard top rail, rear wall and top wall without a cavity does not have this hinge/buckling effect, nor does it absorb a high level of stress over a large volumetric area of the top rail, rear wall and top wall. Therefore, the standard strikeface does not contract and then recoil as much as strikeface 2712. Further, both a larger region of strikeface 2712, top rail 2715, rear wall 2923, and top wall 2719 absorb more stress than the same crown region of a standard golf club head with a standard top rail, top wall and no cavity. In many embodiments, although there is greater stress along a greater area above cavity 2730 than the same area in a standard club without the cavity, the durability of the club head with and without the cavity is the same. By adding more spring to the back end of the club (due to the inward inclination of a portion of top wall 2719 toward strikeface 2712), more force is displaced throughout the volume of the structure. The stress is observed over a greater area of strikeface 2712, top rail 2715, rear wall 2923, and top wall 2719 of golf club head 2700. Peak stresses can be seen in the standard top rail club head. However, more peak stresses are seen in golf club head 2700 but distributed over a large volume of the material. The hinge and bend regions of golf club head 2700 (i.e., the region above cavity 2730 and cavity 2730 itself) will not deform as long as the stress does not meet the critical buckling threshold. Cavity 2730 and its placement can be designed to be under the critical K value of the buckling threshold.

[0103] As shown in FIG. 17, a further deflection feature of the golf club head 2700 can be the uniform thinned region 3160, located at the sole 2706 and stretching between the rear 2710 of the body 2701 and the strikeface 2712, toward a cascading sole portion of the sole (as described in greater detail below). The uniform thinned region 3160 can provide multiple benefits. First, the uniform thinned region 3160 can reduce stress on the strikeface 2712 caused during impact with the golf ball. Second, the uniform thinned region 3160 can bend allowing the strikeface 2712 to experience greater deflection. Third, the uniform thinned region 3160 removes weight from the sole area, allowing the weight to be redistributed more toward the rear of the golf club head 2700. At impact, the energy imparted to the strikeface 2712 by the golf ball can cause the uniform thinned region 3160 to bend outward, which in turn increases the strikeface 2712 deflection. After bending, the uniform thinned region 3160 rebounds back to its original position returning the majority of the energy from impact back to the golf ball. The result is the golf club head 2700 imparts increased ball speeds and greater travel distances to the golf ball after impact.

[0104] In some embodiments, body 2701 can comprise stainless steel, titanium, aluminum, a steel alloy (e.g. 455 steel, 475 steel, 431 steel, 17-4 stainless steel, maraging steel), a titanium alloy (e.g. Ti 7-4, Ti 6-4, T-9S, Ti SSAT2041, Ti SP700, Ti 15-0-3, Ti 15-5-3, Ti 3-8-6-4-4, Ti 10-2-3, Ti 15-3-3-3, Ti-6-6-2, Ti-185, or any combination thereof), an aluminum alloy, or a composite material. In other embodiments, body 2701 can comprise carpenter grade 455 steel, carpenter grade 475 steel, C300 steel, C350 steel, a Ni-Co-Cr steel alloy, a quench and tempered steel alloy, or 565 steel. In some embodiments, strikeface 2712 can comprise stainless steel, titanium, aluminum, a steel alloy (e.g. 455 steel, 475 steel, 431 steel, 17-4 stainless steel, maraging steel), a titanium alloy (e.g. Ti 7-4, Ti 6-4, T-9S, Ti SSAT2041, Ti SP700, Ti 15-0-3, Ti 15-5-3, Ti 3-8-6-4-4, Ti 10-2-3, Ti 15-3-3-3, Ti-6-6-2, Ti-185, or any combination thereof), an aluminum alloy, or a composite material. In other embodiments, strikeface 2712 can comprise carpenter grade 455 steel, carpenter grade 475 steel, C300 steel, C350 steel, a Ni-Co-Cr steel alloy, a quench and tempered steel alloy, or 565 steel. In some embodiments, body 2701 can comprise the same material as strikeface 2712. In some embodiments, body 2701 can comprise a different material than strikeface 2712.

[0105] FIG. 18 illustrates a back perspective view of an embodiment of golf club head 3200, and FIG. 19 illustrates a back heel-side perspective view of golf club head 3200 according to the embodiment of FIG. 18. In some embodiments, golf club head 3200 can be similar to golf club head 1000 (FIG. 1), golf club head 2200 (FIG. 8), and/or golf club head 2700 (FIG. 13). Golf club head 3200 can be an iron-type golf club head. In other embodiments, golf club head 3200 can be a hybrid-type, or a fairway wood-type golf club head. In some embodiments, golf club head 3200 does not comprise a badge or a custom tuning port.

[0106] Golf club head 3200 comprises a body 3201. In some embodiments, body 3201 can be similar to body 1001 (FIG. 1), body 2201 (FIG. 8), and/or body 2701 (FIG. 13). In some embodiments, the body 3201 is hollow. In other embodiments, the body is at least partially hollow. Body 3201 comprises an exterior surface 3203, a strikeface 3212, a heel region 3202, a toe region 3204 opposite the heel region 3202, a sole 3206, a top rail 3215, and a rear 3210.

[0107] Body 3201 of FIGS. 18-22 further comprises a blade length. The blade length for body 3201 can be measured similar to blade length 3725 as shown and described in FIG. 29 (i.e., a measurement parallel to the flat surface of the strikeface 3712, from a toe edge 3726 of the strikeface 3712, to strikeface end 3727 right before the strikeface 3712 integrally curves into the hosel). The blade length of the body 3201 can range from 6.86 cm (2.70 inches) to 7.62 cm (3.00 inches). For example, in some embodiments, the body 3201 can comprise a blade length of 6.96 cm (2.74 inches), 7.06 cm (2.78 inches), 7.16 cm (2.82 inches), 7.26 cm (2.86 inches), 7.37 cm (2.90 inches), 7.47 cm (2.94 inches), 7.57 cm (2.98 inches), or 7.62 cm (3.00 inches).

[0108] The body 3201 further comprises a uniform thinned region transitioning from the bottom of the strikeface 3212 to the sole 3206, toward a cascading sole portion of the sole (as described in greater detail below). In the illustrated embodiment, the uniform thinned region comprises a sole thickness measured perpendicular from the exterior surface 3203 to the interior surface at the uniform thinned region, which can remain constant from the bottom of the strikeface 3212 to adjacent the cascading sole portion of the sole. In some embodiments, the sole thickness of the uniform thinned region can be thinner than a conventional sole. For example, in some embodiments, the sole thickness of the uniform thinned region may range from approximately 1.02 mm (0.040 inch) to 2.03 mm (0.080 inch). In other embodiments, the sole thickness of the uniform thinned region may be within the range of 1.02 mm (0.040 inch) to 1.27 mm (0.050 inch), 1.27 mm (0.050 inch) to 1.52 mm (0.060 inch), 1.52 mm (0.060 inch) to 1.78 mm (0.070 inch), 1.78 mm (0.070 inch) to 2.03 mm (0.080 inch), 1.02 mm (0.040 inch) to 1.40 mm (0.055 inch), 1.14 mm (0.045 inch) to 1.52 mm (0.060 inch), 1.27 mm (0.050 inch) to 1.65 mm (0.065 inch), 1.40 mm (0.055 inch) to 1.78 mm (0.070 inch), 1.52 mm (0.060 inch) to 1.90 mm (0.075 inch), or 1.65 mm (0.065 inch) to 2.03 mm (0.080 inch). For example, the sole thickness of the uniformed thinned region can be 1.02 mm (0.040 inch), 1.14 mm (0.045 inch), 1.27 mm (0.050 inch), 1.52 mm (0.060 inch), 1.65 mm (0.065 inch), 1.78 mm (0.070 inch), 1.90 mm (0.075 inch), or 2.03 mm (0.080 inch).

[0109] FIG. 20 illustrates a cross-section of golf club head 3200 along the cross-sectional line XXXIV-XXXIV in FIG. 18, according to one embodiment. As seen in FIG. 18, strikeface 3212 comprises a high region 3476, a middle region 3474, and a low region 3472. Rear 3210 can comprise an upper region 3211, a lower region 3213, and a cavity 3230. Upper region 3211 comprises top rail 3215, a rear wall 3423, and a top wall 3219. In many embodiments, the rear wall 3423 of rear 3210 is located below and adjacent to the top rail 3215, and the top wall 3219 of rear 3210 is located below and adjacent to rear wall 3423. Lower region 3213 comprises a back wall 3421, and a lower exterior wall 3427. Cavity 3230 is located on the exterior surface 3203, below the top rail 3215 and rear wall 3423, above the lower exterior wall 3427 of rear 3210, and is defined by at least in part by upper region 3211 and lower region 3213.

[0110] In some embodiments, top rail 3215 of the upper region 3211 can be a flatter and taller top rail or skirt than in irons known to one skilled in the art. The flatter and taller rail 3215 can compensate for mis-hits on strikeface 3212 to increase playability off the tee. In some embodiments, the length of top rail 3215, measured from heel region 3202 to toe region 3204, can be 70% to 95% of the length of golf club head 3200. In many embodiments, cavity 3230 comprises a top rail box spring design. In many embodiments, top rail 3215 and cavity 3230 provide an increase in the overall bending of strikeface 3212. In some embodiments, the bending of strikeface 3212 can allow for a 2% to 5% increase of energy. Cavity 3230 allows for strikeface 3212 to be thinner and allow additional overall bending. For some fairway iron-type golf club head embodiments, cavity 3230 can be a reverse scoop or indentation of rear 3210 with body 3201 comprising a greater thickness toward sole 3206.

[0111] In some embodiments, a height 3480 of rear wall 3423 of upper region 3211 of rear 3210 can range from 0.115 cm (0.292 inch) to 0.25 cm (0.635 inch), or 0.130 cm (0.330 inch) to 0.20 cm (0.508 inch). For example, in some embodiments, the height 3480 of rear wall 3423 of the upper region 3211 of rear 3210 can be 0.115 cm (0.292 inch), 0.125 cm (0.318 inch), 0.135 cm (0.343 inch), 0.145 cm (0.368 inch), 0.155 cm (0.394 inch), 0.165 cm (0.419 inch), 0.175 cm (0.445 inch), 0.185 cm (0.470 inch), 0.195 cm (0.495 inch), or 0.250 cm (0.635 inch). In some embodiments, the height 3480 of rear wall 3423 of the upper region 3211 of rear 3210 can range from 0.150 cm (0.381 inch) to 0.210 cm (0.533 inch). In some embodiments, the height 3480 of rear wall 3423 of the upper region 3211 of rear 3210 can be 0.166 cm (0.422 inch). In some embodiments, the height 3480 of rear wall 3423 of upper region 3211 of rear 3210 can range from 3% to 15% of the height of the golf club head 3200.

[0112] The height 3480 of rear wall 3423 of the upper region 3211 of rear 3210, as described herein, allows cavity 3230 to absorb at least a portion of the stress on strikeface 3212 during impact with a golf ball. A golf club head having a rear wall height greater than rear wall height 3480 described herein would absorb less stress (and allow less strikeface deflection) in impact than golf club head 3200 described herein, due to increased dispersion of the impact stress along the top rail prior to reaching the cavity.

[0113] In some embodiments, cavity 3230 is located above a lower region 3213 of rear 3210 and is defined at least in part by upper region 3211 and lower region 3213 of rear 3210. Cavity 3230 comprises top wall 3219, and back wall 3421. A first reference point 3422 is located between the top rail 3215 and rear wall 3423. A second reference point 3482 is located between rear wall 3423 and top wall 3219. A first inflection point 3486 is located between top wall 3219 of cavity 3230 and back wall 3421. A third reference point 3424 is point located on top wall 3219 closest to the strikeface 3212. First reference point 3422 and second reference point 3482 create a first reference line 3429. Second reference point 3482 and third reference point 3424 create a second reference line 3425. Third reference point 3424 and first inflection point 3486 create a third reference line 3426.

[0114] Golf club head 3200 further comprises a height 3488 of top wall 3219, measured parallel to strikeface 3212 and from the second reference point 3482 to first inflection point 3486. In many embodiments, height 3488 can range from 0.254 cm (0.100 inch) to 1.778 cm (0.700 inch). For example, height 3488 can be 0.254 cm (0.100 inch), 0.381 cm (0.150 inch), 0.508 cm (0.200 inch), 0.635 cm (0.250 inch), 0.762 cm (0.300 inch), 0.899 cm (0.350 inch), 1.016 cm (0.400 inch), 1.143 cm (0.450 inch), 1.270 cm (0.500 inch), 1.397 cm (0.550 inch), 1.524 cm (0.600 inch), 1.651 cm (0.650 inch), or 1.778 cm (0.700 inch). In many embodiments, height 3488 can range from 0.762 cm (0.300 inch) to 1.397 cm (0.550 inch). In some embodiments, height 3488 of top wall 3219 can be 0.762 cm (0.300 inch), 0.838 cm (0.330 inch), 0.914 cm (0.360 inch), 0.991 cm (0.390 inch), 1.067 cm (0.420 inch), 1.143 cm (0.450 inch), 1.219 cm (0.480 inch), 1.295 cm (0.510 inch), or 1.372 cm (0.540 inch).

[0115] In many embodiments, second reference point 3482 can range from 0.191 cm (0.075 inch) to 2.54 cm (1.00 inches) or 0.381 cm (0.150 inch) to 0.457 cm (0.180 inches) to apex 3428 of top rail 3215. For example, the second reference point 3482 can be 0.191 cm (0.075 inch), 0.241 cm (0.095 inch), 0.292 cm (0.115 inch), 0.343 cm (0.135 inch), 0.394 cm (0.155 inch), 0.445 cm (0.175 inch), 0.483 cm (0.190 inch), or 2.54 cm (1.000 inch) below the apex 3428 of top rail 3215.

[0116] In many embodiments, top wall 3219 of cavity 3230 can be substantially parallel to strikeface 3212. In other embodiments, top wall 3219 is not substantially parallel to strikeface 3212. In some embodiments, top wall 3219 of cavity 3230 is substantially parallel to rear wall 3423 of upper region 3211 of rear 3210. In a number of embodiments, a portion of top wall 3219 extends away from top rail 3215 toward strikeface 3212 from second reference point 3482 to third reference point 3424. In some embodiments, the portion of top wall 3219 extending away from top rail 3215 toward strikeface 3212 from second reference point 3482 to third reference point 3424 can be straight, curved upward, or curved downward. In many embodiments, a portion of top wall 3219 of cavity 3230 is angled away from strikeface 3212 from third reference point 3424 to first inflection point 3486. In some embodiments, the portion of top wall 3219 angled away from strikeface 3212 from third reference point 3424 to first inflection point 3486 can be straight, curved upward, or curved downward. This orientation of top wall 3219 creates a buckling point, hinge point or plastic hinge to direct the stress of impact toward cavity 3230 and to allow increased flexing of strikeface 3212 during impact.

[0117] Lower region 3213 of rear 3210 comprises back wall 3421 of cavity 3230 and lower exterior wall 3427. In some embodiments, back wall 3421 of cavity 3230 can have a back wall length 3490 measured from first inflection point 3486 to a second inflection point 3492 located between the back wall 3421 and the lower exterior wall 3427. In a number of embodiments, back wall length 3490 can range from 0.254 cm (0.100 inch) to 0.889 cm (0.350 inch). In many embodiments, back wall length 3490 can be 0.254 cm (0.100 inch), 0.318 cm (0.125 inch), 0.381 cm (0.150 inch), 0.445 cm (0.175 inch), 0.508 cm (0.200 inch), 0.572 cm (0.225 inch), 0.635 cm (0.250 inch), 0.699 cm (0.275 inch), 0.762 cm (0.300 inch), 0.826 cm (0.325 inch), or 0.889 cm (0.350 inch).

[0118] In some embodiments, a lower angle 3451 can be measured from between the back wall 3421 and the lower exterior wall 3427. In some embodiments, lower angle 3451 can be less than 180 degrees. In a number of embodiments, lower angle 3451 can range from 30 degrees to 180 degrees. In various embodiments, lower angle 3451 can range from 70 degrees to 130 degrees. In some embodiments, lower angle 3451 can be 70 degrees, 75 degrees, 80 degrees, 85 degrees, 90 degrees, 95 degrees, 100 degrees, 105 degrees, 110 degrees, 115 degrees, 120 degrees, 125 degrees, or 130 degrees.

[0119] In some embodiments, an inflection angle 3496 measured from third reference line 3426 to back wall 3421 can range from 70 degrees to 150 degrees. In some embodiments, inflection angle 3496 can range from 90 degrees to 130 degrees. In some embodiments, inflection angle 3496 can be 70 degrees, 75 degrees, 80 degrees, 85 degrees, 90 degrees, 95 degrees, 100 degrees, 105 degrees, 110 degrees, 115 degrees, 120 degrees, 125 degrees, 130 degrees, 135 degrees, 140 degrees, 145 degrees, or 150 degrees. In many embodiments, inflection angle 3496 allows first inflection point 3486 to act as a buckling point or plastic hinge upon golf club head 3200 impacting the golf ball at strikeface 3212. In some embodiments, the wall thickness at the first inflection point 3486 can be thinner than at the top wall 3219 and back wall 3421.

[0120] In many embodiments, first inflection point 3486, adjacent to back wall 3421 can range from 0.508 cm (0.20 inch) to 2.54 cm (1.0 inch), or 1.27 cm (0.5 inch) to 1.778 cm (0.7 inch) below the apex 3428 of top rail 3215. For example, the first inflection point 3486 can be 0.508 cm (0.20 inch), 0.635 cm (0.25 inch), 0.762 cm (0.30 inch), 0.889 cm (0.35 inch), 1.016 cm (0.40 inch), 1.143 cm (0.45 inch), 1.27 cm (0.50 inch), 1.397 cm (0.55 inch), 1.524 cm (0.60 inch), 1.651 cm (0.65 inch), 1.778 cm (0.70 inch), 1.905 cm (0.75 inch), 2.032 cm (0.80 inch), 2.159 cm (0.85 inch), 2.286 cm (0.90 inch), 2.413 cm (0.95 inch), or 2.54 cm (1.0 inch) below the apex 3428 of top rail 3215. In some embodiments, the maximum height of the back wall 3421, measured perpendicular to a ground 3403 when golf club head 3200 is at address, from a lowest point of sole 3206 to first inflection point 3486, can range from 0.635 cm (0.25 inch) to 7.62 cm (3 inches), or 1.27 cm (0.50 inch) to 5.08 cm (2 inches). For example, the first inflection point 3486 can be 0.635 cm (0.25 inch), 0.953 cm (0.375 inch), 1.27 cm (0.5 inch), 1.59 cm (0.625 inch), 1.91 cm (0.75 inch), 2.10 cm (0.825 inch), 2.54 cm (1.0 inch), 2.88 cm (1.125 inches), 3.18 cm (1.25 inches), 3.49 cm (1.375 inches), 3.81 cm (1.5 inches), 4.12 cm (1.625 inches), 4.45 cm (1.75 inches), 4.76 cm (1.875 inches), 5.08 cm (2.0 inches), 5.40 cm (2.125 inches), 5.71 cm (2.25 inches), 6.03 cm (2.375 inches), 6.35 cm (2.5 inches), 6.67 cm (2.625 inches), 7.00 cm (2.75 inches), 7.30 cm (2.875 inches) or 7.62 cm (3.0 inches) above a lowest point of sole 3206 to the ground 3403 when golf club head 3200 is at address.

[0121] In some embodiments, a back wall angle 3405 measured from back wall 3421 to ground plane 3403 can range from 15 degrees to 45 degrees. In some embodiments, back wall angle 3405 can be 15 degrees, 16 degrees, 17 degrees, 18 degrees, 19 degrees, 20 degrees, 21 degrees, 22 degrees, 23 degrees, 24 degrees, 25 degrees, 26 degrees, 27 degrees, 28 degrees, 29 degrees, 30 degrees, 31 degrees, 32 degrees, 33 degrees, 34 degrees, 35 degrees, 36 degrees, 37 degrees, 38 degrees, 39 degrees, 40 degrees, 41 degrees, 42 degrees, 43 degrees, 44 degrees, or 45 degrees.

[0122] In some embodiments as illustrated in FIG. 18, cavity 3230 can further comprise at least one channel 3239. In many embodiments, channel 3239 extends from heel region 3202 to toe region 3204. Channel 3239 comprises a channel width measured from second reference point 3482 to top wall 3219 substantially parallel to ground plane 3403, where channel width can vary in a direction from top rail 3215 to sole 3206. In some embodiments, a maximum channel width 3432, measured from first inflection point 3486 to second reference point 3482 substantially parallel to ground plane 3403, can be substantially constant throughout the channel 3230 from heel region 3202 to toe region 3204. In some embodiments as illustrated in FIG. 20, maximum channel width 3432 can range from 1 mm (0.039 inch) to 15 mm (0.590 inch), or 3.81 mm (0.150 inch) to 10.16 mm (0.400 inch). For example, maximum channel width 3432 can be 1.0 mm (0.039 inch), 2 mm (0.079 inch), 3 mm (0.12 inch), 4 mm (0.16 inch), 5 mm (0.20 inch), 6 mm (0.24 inch), 7 mm (0.28 inch), 8 mm (0.31 inch), 10 mm (0.39 inch), or 15 mm (0.59 inch). In other embodiments, a channel toe region width of channel 3239 is less than a channel heel region width of channel 3239. In other embodiments, the channel heel region width is less than the channel toe region width. In other embodiments, a channel middle region width of channel 3239 can be less than at least one of the channel heel region width or the channel toe region width. In other embodiments, the channel middle region width can be greater than at least one of the channel heel region width or the channel toe region width. In some embodiments, channel 3239 is symmetrical from heel to toe. In other embodiments, channel 3239 is non-symmetrical. In other embodiments, channel 3239 can further comprise at least two partial channels. In some embodiments, channel 3239 can comprise a series of partial channels interrupted by one or more bridges. In some embodiments, the one or more bridges can be approximately the same thickness as the thickness of upper region 3211 of top rail 3215.

[0123] Maximum channel width 3432, as described herein, allows absorption of stress from strikeface 3212 on impact. A golf club head having a channel width less than the maximum channel width 3432 described here (e.g., a golf club head with a less pronounced cavity) would allow less stress absorption from the strikeface on impact (due to less material on the upper region 3211 of rear 3210), and therefore would experience less strikeface deflection than golf club head 3200 described herein.

[0124] In many embodiments, back cavity 3230 further comprises a cavity angle 3435. Back cavity angle 3435 is measured from first reference line 3429 to second reference line 3425. In many embodiments, back cavity angle 3435 can range from 15 degrees to 80 degrees. In some embodiments, back cavity angle 3435 can be 15 degrees, 20 degrees, 25 degrees, 30 degrees, 35 degrees, 40 degrees, 45 degrees, 50 degrees, 55 degrees, 60 degrees, 65 degrees, 70 degrees, 75 degrees, or 80 degrees.

[0125] FIG. 21 illustrates a view of top rail 3215 and a portion of rear 3210 of the cross-section of golf club head 3200 of FIG. 18 different from cross-section of golf club head 1200 as shown in FIG. 4. In many embodiments, golf club head 3200 comprises a rear angle 3540, a top rail angle 3545, and a strikeface angle 3550. Rear angle 3540 is measured from second reference line 3425 to rear wall 3423 of upper region 3211. In many embodiments, rear angle 3540 can range from 70 degrees to 140 degrees. In some embodiments, rear angle 3540 can be 70 degrees, 75 degrees, 80 degrees, 85 degrees, 90 degrees, 100 degrees, 105 degrees, 110 degrees, 115 degrees, 120 degrees, 125 degrees, 130 degrees, 135 degrees, or 140 degrees. Top rail angle 3545 is measured from rear wall 3423 of upper region 3211 to top rail 3215. In many embodiments, top rail 3545 can range from 35 degrees to 120 degrees or 70 degrees to 110 degrees. In some embodiments, top rail angle 3545 can be 35 degrees, 40 degrees, 45 degrees, 50 degrees, 55 degrees, 60 degrees, 65 degrees, 70 degrees, 75 degrees, 80 degrees, 85 degrees, 90 degrees, 95 degrees, 100 degrees, 105 degrees, 110 degrees, 115 degrees, or 120 degrees. Strikeface angle 3550 is measured from strikeface 3212 to top rail 3215. In many embodiments, strikeface angle 3550 can range from 70 degrees to 160 degrees or 70 degrees to 110 degrees. In some embodiments, strikeface angle 3550 can be 70 degrees, 75 degrees, 80 degrees, 90 degrees, 95 degrees, 100 degrees, 105 degrees, 110 degrees, 115 degrees, 120 degrees, 125 degrees, 130 degrees, 135 degrees, 140 degrees, 145 degrees, 150 degrees, 155 degrees, or 160 degrees.

[0126] Upper region 3211 further comprises a minimum gap 3590 measured from third reference point 3424 of an inner surface 3419 of top wall 3219 to an inner surface 3419 of strikeface 3212, perpendicular to strikeface 3212. In some embodiments, minimum gap 3590 can range from 2 mm (0.079 inch) to 6 mm (0.24 inch). For example, the minimum gap 3590 can be 2 mm (0.079 inch), 3 mm (0.118 inch), 4 mm (0.16 inch), 5 mm (0.197 inch), or 6 mm (0.24 inch). In other embodiments, the minimum gap 3590 can range from 3 mm (0.118 inch) to 4 mm (0.16 inch). In some embodiments, the minimum gap 3590 can be 3.429 mm (0.135 inch).

[0127] FIG. 22 illustrates a simplified cross-sectional view of golf club head 3200, similar to the detailed cross-section of golf club head 3200 illustrated in FIG. 20. Golf club head 3200 includes cavity 3230, upper region 3211, lower region 3213, and exterior surface 3203. In many embodiments, a maximum upper distance 3692 measured as the perpendicular distance from exterior surface 3203 of strikeface 3212 to exterior surface 3203 of second reference point 3482 of upper region 3211 can range from 5 mm (0.20 inch) to 15 mm (0.59 inch). For example, maximum upper distance 3692 can be 5 mm (0.20 inch), 6 mm (0.24 inch), 7 mm (0.28 inch), 8 mm (0.31 inch), 8.89 mm (0.35 inch), 10 mm (0.39 inch), 11 mm (0.43 inch), 12 mm (0.47 inch), 13 mm (0.51 inch), 14 mm (0.55 inch), or 15 mm (0.59 inch). In some embodiments, maximum upper distance 3692 can be 9.09 mm (0.348 inch). Further, a minimum upper distance 3694 measured as the perpendicular distance from exterior surface 3203 of strikeface 3212 to exterior surface 3203 of third reference point 3424 can range from 2.54 mm (0.10 inch) to 12 mm (0.47 inch). For example, minimum upper distance 3694 can be 2.54 mm (0.10 inch), 4 mm (0.16 inch), 5 mm (0.20 inch), 6 mm (0.24 inch), 7 mm (0.28 inch), 8 mm (0.31 inch), 9 mm (0.35 inch), 10 mm (0.39 inch), 11 mm (0.43 inch), or 12 mm (0.47 inch). In some embodiments, minimum upper distance 3694 can be 7.85 mm (0.309 inch). Further still, a maximum lower distance 3696 measured as the perpendicular distance from exterior surface 3203 of strikeface 3212 to exterior surface 3203 of a fourth reference point 3420 located between the lower exterior wall 3427 and the sole 3206 can range from 17 mm (0.670 inch) to 25 mm (0.98 inch). For example, maximum lower distance 3696 can be 17 mm (0.670 inch), 18 mm (0.709 inch), 19 mm (0.748 inch), 20 mm (0.787 inch), 21 mm (0.827 inch), 22 mm (0.866 inch), 23 mm (0.906 inch), 24 mm (0.945 inch), or 25 mm (0.98 inch). In some embodiments, maximum lower distance 3696 can be 21.9 mm (0.863 inch). In many embodiments, maximum lower distance 3696 is greater than maximum upper distance 3692 and maximum upper distance 3692 is greater than minimum upper distance 3694.

[0128] In many embodiments, cavity 3230 can provide an increase in golf ball speed over golf club head 1200, or other standard golf club heads, can reduce the spin rate of standard hybrids club heads, and can increase the launch angle over both the standard hybrid and iron club heads. In many embodiments, the shape of cavity 3230 determines the level of spring and timing of the response of golf club head 3200. When the golf club ball impacts strikeface 3212 of club head 3200 with cavity 3230, strikeface 3212 springs back like a drum, and a rear 3210 bends in a controlled buckle manner. In many embodiments, top rail 3215 can absorb more stress over greater volumetric space than a top rail in a golf club head without cavity 3230. The length, depth and width of cavity 3230 can vary. These parameter provide control regarding how much spring back is present in the overall design of club head 3200.

[0129] Upon impact with the golf ball, strikeface 3212 can bend inward at a greater distance than on a golf club without cavity 3230. In some embodiments, strikeface 3212 has a 10% to a 50 % greater deflection than a strikeface on a golf club head without cavity 3230. In some embodiments, strikeface 3212 has a 5% to 40% or a 10% to a 20% greater deflection than a strikeface on a golf club head without cavity 3230. For example, strikeface 3212 can have a 5%, 10 %, 15%, 20%, 25%, 30%, 35%, or 40% greater deflection than a strikeface on a golf club head without cavity 3230. In many embodiments, there is both a greater distance of retraction by strikeface 3212 due to the hinge and bending of cavity 3230 over a standard strikeface that does not have a back portion of the club with the cavity.

[0130] In many embodiments, the face deflection is greater with club head 3200 having cavity 3230, as a greater buckling occurs at first inflection angle 3486 of top wall 3219 upon impact with a golf ball. Cavity 3230, however, provides a greater dispersion of stress along top rail 3215, rear wall 3423, and top wall 3219, and the spring back force is transferred from cavity 3230 and first inflection point 3486 of top wall 3219 to strikeface 3212. A standard top rail, rear wall and top wall without a cavity does not have this hinge/buckling effect, nor does it absorb a high level of stress over a large volumetric area of the top rail, rear wall and top wall. Therefore, the standard strikeface does not contract and then recoil as much as strikeface 3212. Further, both a larger region of strikeface 3212, top rail 3215, rear wall 3423, and top wall 3219 absorb more stress than the same crown region of a standard golf club head with a standard top rail, top wall and no cavity. In many embodiments, although there is greater stress along a greater area above cavity 3230 that the same area in a standard club without the cavity, the durability of the club head with without the cavity is the same. By adding more spring to the back end of the club (due to inward inclination of a portion of top wall 3219 toward strikeface 3212), more force is displaced throughout the volume of the structure. The stress is observed over a greater area of strikeface 3212, top rail 3215, rear wall 3423, and top wall 3219 of golf club head 3200. Peak stresses can be seen in the standard top rail club head. However, more peak stresses are seen in golf club head 3200 but distributed over a large volume of the material. The hinge and bend regions of golf club head 3200 (i.e., the region above cavity 3230 and cavity 3230 itself) will not deform as long as the stress does not meet the critical buckling threshold. Cavity 3230 and its placement can be designed to be under the critical K value of the buckling threshold.

[0131] As shown in FIG. 22, a further deflection feature of the golf club head 3200 can be the uniform thinned region 3660, located at the sole 3206 and stretching between the rear 3210 of the body 3201 and the strikeface 3212, toward a cascading sole portion of the sole (as described in greater detail below). The uniform thinned region 3660 can provide multiple benefits. First, the uniform thinned region 3660 can reduce stress on the strikeface 3212 caused during impact with the golf ball. Second, the uniform thinned region 3660 can bend allowing the strikeface 3212 to experience greater deflection. Third, the uniform thinned region 3660 removes weight from the sole area, allowing the weight to be redistributed more toward the rear of the golf club head 3200. At impact, the energy imparted to the strikeface 3212 by the golf ball can cause the uniform thinned region 3660 to bend outward, which in turn increases the strikeface 3212 deflection. After bending, the uniform thinned region 3660 rebounds back to its original position returning the majority of the energy from impact back to the golf ball. The result is the golf club head 3200 imparts increased ball speeds and greater travel distances to the golf ball after impact.

[0132] In some embodiments, body 3201 can comprises stainless steel, titanium, aluminum, a steel alloy (e.g. 455 steel, 475 steel, 431 steel, 17-4 stainless steel, maraging steel), a titanium alloy (e.g. Ti 7-4, Ti 6-4, T-9S, Ti SSAT2041, Ti SP700, Ti 15-0-3, Ti 15-5-3, Ti 3-8-6-4-4, Ti 10-2-3, Ti 15-3-3-3, Ti-6-6-2, Ti-185, or any combination thereof), an aluminum alloy, or a composite material. In other embodiments, body 3201 can comprise carpenter grade 455 steel, carpenter grade 475 steel, C300 steel, C350 steel, a Ni-Co-Cr steel alloy, a quench and tempered steel alloy, or 565 steel. In some embodiments, strikeface 3212 can comprise stainless steel, titanium, aluminum, a steel alloy (e.g. 455 steel, 475 steel, 431 steel, 17-4 stainless steel, maraging steel), a titanium alloy (e.g. Ti 7-4, Ti 6-4, T-9S, Ti SSAT2041, Ti SP700, Ti 15-0-3, Ti 15-5-3, Ti 3-8-6-4-4, Ti 10-2-3, Ti 15-3-3-3, Ti-6-6-2, Ti-185, or any combination thereof), an aluminum alloy, or a composite material. In other embodiments, strikeface 3212 can comprise carpenter grade 455 steel, carpenter grade 475 steel, C300 steel, C350 steel, a Ni-Co-Cr steel alloy, a quench and tempered steel alloy, or 565 steel. In some embodiments, body 2701 can comprise the same material as strikeface 3212. In some embodiments, body 2701 can comprise a different material than strikeface 3212.

[0133] FIG. 23 illustrates a back perspective view of an embodiment of golf club head 3700 and FIG. 24 illustrates a back heel-side perspective view of golf club head 3700 according to the embodiment of FIG. 23. In some embodiments, golf club head 3700 can be similar to golf club head 1000 (FIG. 1), golf club head 2200 (FIG. 8), golf club head 2700 (FIG. 13), and/or golf club head 3200 (FIG. 18). Golf club head 3700 can be an iron-type golf club head. In other embodiments, golf club head 3700 can be a hybrid-type, or a fairway wood-type golf club head. In some embodiments, golf club head 3700 does not comprise a badge or a custom tuning port.

[0134] Golf club head 3700 comprises a body 3701. In some embodiments, body 3701 can be similar to body 1001 (FIG. 1), body 2201 (FIG. 8), body 2701 (FIG. 13), and/or body 3201 (FIG. 18). In some embodiments, the body 3701 is hollow with an internal cavity 3716. In other embodiments, the body is at least partially hollow. In embodiments wherein body 3701 is hollow or partially hollow, body 3701 can comprise a volume void of internal cavity 3716 ranging from 28 cc (1.71 inches³) to 37.69 cc (2.3 inches³). In some hollow and partially hollow embodiments, body 3701 can comprise a volume of 27.86 cc (1.70 inches³), 29.50 cc (1.80 inches³), 31.14 cc (1.90 inches³), 32.77 cc (2.00 inches³), 34.41 cc (2.10 inches³), 36.05 cc (2.20 inches³), or 37.69 cc (2.30 inches³). Body 3701 further comprises an exterior surface 3703, a strikeface 3712, a heel region 3702, a toe region 3704 opposite the heel region 3702, a sole 3706, a top rail 3715, and a rear 3710.

[0135] Body 3701 of FIGS. 23-29 further comprises a blade length 3725, a toe edge 3726, and a strikeface end 3727. The toe edge 3726 is the farthest edge of the strikeface 3712 at the toe region 3704, and the strikeface end 3727 is the end of the strikeface 3712 at the heel region 3702, right before the strikeface 3712 integrally curves into the hosel. As illustrated in FIG. 29, blade length 3725 is the distance measured from the toe edge 3726 to the strikeface end 3727. The blade length 3725 is measured parallel to the flat surface of the strikeface 3712 between the toe edge 3726 and the strikeface end 3727 at the heel end 3702 before the strikeface 3712 integrally curves with the hosel. The blade length of the body 3701 can range from 6.86 cm (2.70 inch) to 7.62 cm (3.00 inch). For example, in some embodiments the body 3701 can comprise a blade length of 6.96 cm (2.74 inch), 7.06 cm (2.78 inch), 7.16 cm (2.82 inch), 7.26 cm (2.86 inch), 7.37 cm (2.90 inch), 7.47 cm (2.94 inch), 7.57 cm (2.98 inch), or 7.62 cm (3.00 inch).

[0136] The body 3701 further comprises a uniform thinned region transitioning from the bottom of the strikeface 3712 to the sole 3706, toward a cascading sole portion of the sole (as described in greater detail below). In the illustrated embodiment, the uniform thinned region comprises a sole thickness measured perpendicular from the exterior surface 3703 to an interior surface 3919 at the uniform thinned region, which can remain constant from the bottom of the strikeface 3712 to adjacent the cascading sole portion of the sole. In some embodiments, the sole thickness of the uniform thinned region can be thinner than a conventional sole. For example, in some embodiments, the sole thickness of the uniform thinned region may range from approximately 1.016 mm (0.040 inch) to 2.032 mm (0.080 inch). In other embodiments, the sole thickness of the uniform thinned region may be within the range of 1.016 mm (0.040 inch) to 1.270 mm (0.050 inch), 1.270 mm (0.050 inch) to 1.524 mm (0.060 inch), 1.524 mm (0.060 inch) to 1.778 mm (0.070 inch), 1.778 mm (0.070 inch) to 2.032 mm (0.080 inch), 1.016 mm (0.040 inch) to 1.397 mm (0.055 inch), 1.143 mm (0.045 inch) to 1.524 mm (0.060 inch), 1.270 mm (0.050 inch) to 1.651 mm (0.065 inch), 1.397 mm (0.055 inch) to 1.778 mm (0.070 inch), 1.524 mm (0.060 inch) to 1.905 mm (0.075 inch), or 1.651 mm (0.065 inch) to 2.032 mm (0.080 inch). For example, the sole thickness of the uniformed thinned region can be 1.016 mm (0.040 inch), 1.143 mm (0.045 inch), 1.270 mm (0.050 inch), 1.524 mm (0.060 inch), 1.651 mm (0.065 inch), 1.778 mm (0.070 inch), 1.905 mm (0.075 inch), or 2.032 mm (0.080 inch).

[0137] FIG. 25 illustrates a cross-section of golf club head 3700 along the cross-sectional line XXXIX-XXXIX in FIG. 23, according to one embodiment. As seen in FIG. 25, strikeface 3712 comprises a high region 3976, a middle region 3974, and a low region 3972. Rear 3710 can comprise an upper region 3711, a lower region 3713, and a cavity 3730.

[0138] Upper region 3711 of rear 3710 comprises top rail 3715, a rear wall 3923, a top wall 3719, and a back wall 3921. In many embodiments, the rear wall 3923 of rear 3710 is located below and adjacent to the top rail 3715, the top wall 3719 of rear 3710 is located below and adjacent to the rear wall 3923, and the back wall 3721 is located below and adjacent to the top wall 3719. Upper region further comprises a first reference point 3922 located between top rail 3715 and rear wall 3923, a second reference point 3982 located between rear wall 3923 and top wall 3719, a first inflection point 3986 located between top wall 3719 and back wall 3921, and a second inflection point 3992 located between the back wall 3921, and a bottom incline 3925 of the lower region 3713. First reference point 3922 and second reference point 3982 create a reference line 3939 as illustrated in FIG. 26.

[0139] The top wall 3719 is angled toward the strikeface and away from the top rail 3715 in a direction toward the first inflection point 3986. The described configuration of the top wall 3719 allows increased bending of the top rail 3715 of the club head 3700 on impact with a golf ball, compared with a club head devoid of the described top wall configuration.

[0140] Cavity 3730 is located on the exterior surface 3703, below top rail 3715 and rear wall 3923, above the lower region 3713 of rear 3710, and is defined by at least in part by upper region 3711 and lower region 3713.

[0141] In some embodiments, top rail 3715 of the upper region 3711 can be a flatter and taller top rail or skirt than in irons known to one skilled in the art. The flatter and taller rail can compensate for mishits of strikeface 3712 to increase playability off the tee. In some embodiments, the length of top rail 3715, measured from heel region 3702 to toe region 3704, can be 70% to 95% of the length of golf club head 3700. In many embodiments, cavity 3730 comprises a top rail box spring design. For some fairway iron-type golf club head embodiments, cavity 3730 can be a reverse scoop or indentation of rear 3710 with body 3701 comprising a greater thickness toward sole 3706. In many embodiments, top rail 3715 and cavity 3730 provide an increase in the overall bending of strikeface 3712. In some embodiments, the bending of strikeface 3712 can allow for a 2% to 5% increase of energy. Cavity 3730 allows for strikeface 3712 to be thinner and allow additional overall bending.

[0142] Strikeface 3712 of body 3701 comprises a thickness 3954 measured perpendicularly to strikeface 3712 from the exterior surface 3703 to the interior surface 3919. The thickness 3954 of the strikeface 3712 can range from 1.524 mm (0.060 inch) to 2.794 mm (0.110 inch). For example, the thickness 3954 of the strikeface 3712 can be 1.524 mm (0.060 inch), 1.651 mm (0.065 inch), 1.778 mm (0.070 inch), 1.905 mm (0.075 inch), 2.032 mm (0.080 inch), 2.159 mm (0.085 inch), 2.286 mm (0.090 inch), 2.413 mm (0.095 inch), 2.540 mm (0.100 inch), 2.667 mm (0.105 inch), or 2.794 mm (0.110 inch). In some embodiments, thickness 3954 of strikeface 3712 can remain constant from heel region 3702 to toe region 3704, and/or from top rail 3715 to sole 3706. In other embodiments, thickness 3954 of strikeface 3712 can vary from heel region 3702 to toe region 3704, and/or from top rail 3715 to sole 3706. For example, the thickness 3954 of strikeface 3712 can be greatest at a central portion of strikeface 3712 near the middle region 3974, and taper along the periphery of strikeface 3712 near the high region 3976, and the low region 3972. In many embodiments, the center of the strikeface 3712 near the middle region 3974 can have a thickness 3954 of 2.540 mm (0.100 inch) and the periphery of the strikeface 3712 can have a thickness 3954 of 2.032 mm (0.080 inch). In other examples, the thickness 3954 can increase, or decrease, or any variation thereof starting at a central region near the middle region 3974 of strikeface 3712 and extending toward the periphery near the high region 3976 and the low region 3972.

[0143] Golf club head 3700 further comprises a height 3980 for rear wall 3923 of upper region 3711 of rear 3710 measured from first reference point 3922 to second reference point 3982. In some embodiments, height 3980 of rear wall 3923 of upper region 3711 of rear 3710 can range from 0.292 cm (0.115 inch) to 0.635 cm (0.250 inch), 0.330 cm (0.130 inch) to 0.508 cm (0.200 inch), or 0.381 cm (0.150 inch) to 0.457 cm (0.180 inch). For example, in some embodiments, the height 3980 of rear wall 3923 of the upper region 3711 of rear 3710 can be 0.292 cm (0.115 inch), 0.318 cm (0.125 inch), 0.343 cm (0.135 inch), 0.368 cm (0.145 inch), 0.394 cm (0.155 inch), 0.419 cm (0.165 inch), 0.445 cm (0.175 inch), 0.470 cm (0.185 inch), 0.495 cm (0.195 inch), or 0.635 cm (0.250 inch). In some embodiments, the height 3980 of rear wall 3923 of the upper region 3711 of rear 3710 can range from 0.381 cm (0.150 inch) to 0.533 cm (0.210 inch). In some embodiments, the height 3980 of rear wall 3923 of the upper region 3711 of rear 3710 can be 0.422 cm (0.166 inch). In some embodiments, the height 3980 of rear wall 3923 of upper region 3711 of rear 3710 can range from 3% to 15% of the height of the golf club head 3700.

[0144] The height 3980 of rear wall 3923 of the upper region 3211 of rear 3210, as described herein, allows cavity 3730 to absorb at least a portion of the stress on strikeface 3712 during impact with a golf ball. A golf club head having a rear wall height greater than rear wall height 3980 described herein would absorb less stress (and allow less strikeface deflection) in impact than golf club head 3700 described herein, due to increased dispersion of the impact stress along the top rail prior to reaching the cavity.

[0145] Rear wall 3923 further comprises a thickness measured perpendicularly from the exterior surface 3703 to the interior surface 3919 of the rear wall 3923. The thickness of the rear wall 3923 can range from 0.94 mm (0.037 inch) to 1.47 mm (0.058 inch), 0.94 mm (0.037 inch) to 1.22 mm (0.048 inch), or 1.07 mm (0.042 inch) to 1.47 mm (0.058 inch). For example, the thickness of the rear wall 3923 can be 0.94 mm (0.037 inch), 1.02 mm (0.040 inch), 1.09 mm (0.043 inch), 1.17 mm (0.046 inch), 1.24 mm (0.049 inch), 1.32 mm (0.052 inch), 1.40 mm (0.055 inch), or 1.47 mm (0.058 inch). The thickness of the rear wall 3923 can aid in stress distribution as well as increase the bending of the strikeface 3712.

[0146] In many embodiments, second reference point 3982 of upper region 3711 of rear 3710 can have a distance ranging from 0.381 cm (0.150 inch) to 2.54 cm (1.00 inch), 0.381 cm (0.150 inch) to 0.457 cm (0.350 inch), 0.457 cm (0.300 inch) to 1.27 cm (0.500 inch), 1.14 cm (0.450 inch) to 1.65 cm (0.650 inch), 1.52 cm (0.600 inch) to 2.03 cm (0.800 inch), or 1.91 cm (0.750 inch) to 2.54 cm (1.00 inch) from apex 3928 of top rail 3715. For example, the second reference point 3982 of upper region 3711 can be 0.381 cm (0.150 inch), 1.14 cm (0.450 inch), 1.52 cm (0.600 inch), 1.91 cm (0.750 inch), 2.29 cm (0.900 inch), or 2.54 cm (1.000 inch) below the apex 3428 of top rail 3215.

[0147] Golf club head 3700 further comprises a length 3988 of top wall 3719 of upper region 3711, measured from the second reference point 3982 to first inflection point 3986. In many embodiments, top wall length 3988 can range from 0.076 cm (0.030 inch) to 0.254 cm (0.100 inch). In many embodiments, top wall length 3988 can range from 0.076 cm (0.030 inch) to 0.127 cm (0.050 inch), 0.102 cm (0.040 inch) to 0.152 cm (0.060 inch), 0.127 cm (0.050 inch) to 0.203 cm (0.080 inch), or 0.178 cm (0.070 inch) to 0.254 cm (0.100 inch). For example, top wall length 3988 can be 0.076 cm (0.030 inch), 0.089 cm (0.035 inch), 0.102 cm (0.040 inch), 0.114 cm (0.045 inch), 0.127 cm (0.050 inch), 0.140 cm (0.055 inch), 0.152 cm (0.060 inch), 0.165 cm (0.065 inch), 0.178 cm (0.070 inch), 0.191 cm (0.075 inch), 0.203 cm (0.080 inch), 0.216 cm (0.085 inch), 0.229 cm (0.090 inch), 0.241 cm (0.095 inch), or 0.254 cm (0.100 inch).

[0148] In a number of embodiments, a portion of top wall 3719 of upper region 3711 extends away from rear wall 3923 at second reference point 3982, toward strikeface 3712 at first inflection point 3986. In some embodiments, the portion of top wall 3719 extending away from rear wall 3923 toward strikeface 3712 can be straight, curved upward, or curved downward. This orientation of top wall 3719 creates a buckling point, hinge point or plastic hinge to direct the stress of impact toward cavity 3730 and to allow increased flexing of strikeface 3712 during impact.

[0149] The first inflection point 3986 of the upper region 3711, can have a distance from the first reference point 3922 ranging from 0.508 cm (0.20 inch) to 2.54 cm (1.0 inch), or 1.27 cm (0.5 inch) to 1.778 cm (0.7 inch). For example, the first inflection point 3986 can be 0.508 cm (0.20 inch), 0.635 cm (0.25 inch), 0.762 cm (0.30 inch), 0.889 cm (0.35 inch), 1.016 cm (0.40 inch), 1.143 cm (0.45 inch), 1.27 cm (0.50 inch), 1.397 cm (0.55 inch), 1.524 cm (0.60 inch), 1.651 cm (0.65 inch), 1.778 cm (0.70 inch), 1.905 cm (0.75 inch), 2.032 cm (0.80 inch), 2.159 cm (0.85 inch), 2.286 cm (0.90 inch), 2.413 cm (0.95 inch), or 2.54 cm (1.0 inch) below the first reference point 3922.

[0150] In some embodiments, upper region 3711 further comprises an inflection angle 3996 measured from top wall 3719 to back wall 3921, wherein inflection angle 3996 can range from 70 degrees to 150 degrees. In some embodiments, inflection angle 3996 of upper region can range from 90 degrees to 130 degrees. In some embodiments, inflection angle 3996 of upper region can be 70 degrees, 75 degrees, 80 degrees, 85 degrees, 90 degrees, 95 degrees, 100 degrees, 105 degrees, 110 degrees, 115 degrees, 120 degrees, 125 degrees, 130 degrees, 135 degrees, 140 degrees, 145 degrees, or 150 degrees. In many embodiments, inflection angle 3996 of upper region allows first inflection point 3986 to act as a buckling point or plastic hinge upon golf club head 3700 impacting the golf ball at strikeface 3712. In some embodiments, the wall thickness at the first inflection point 3986 can be thinner than at the top wall 3719 and back wall 3921.

[0151] In some embodiments, back wall 3921 of cavity 3730 of upper region 3711 can have a back wall length 3990 measured from first inflection point 3986 to second inflection point 3992. In a number of embodiments, back wall length 3990 can range from 0.254 cm (0.100 inch) to 0.889 cm (0.350 inch). In many embodiments, back wall length 3990 can be 0.254 cm (0.100 inch), 0.318 cm (0.125 inch), 0.381 cm (0.150 inch), 0.445 cm (0.175 inch), 0.508 cm (0.200 inch), 0.572 cm (0.225 inch), 0.635 cm (0.250 inch), 0.699 cm (0.275 inch), 0.762 cm (0.300 inch), 0.826 cm (0.325 inch), or 0.889 cm (0.350 inch).

[0152] The back wall 3921 of the cavity 3730 can further comprise a thickness measured perpendicularly from the interior surface 3919 to the exterior surface 3703 of the back wall 3921. The thickness of the back wall 3921 can range from 0.711 mm (0.028 inch) to 0.991 mm (0.039 inch), 0.711 mm (0.028 inch) to 0.813 mm (0.032 inch), or 0.813 mm (0.032 inch) to 0.991 mm (0.039 inch). For example, the thickness of the back wall 3921 can be 0.711 mm (0.028 inch), 0.762 mm (0.030 inch), 0.813 mm (0.032 inch), 0.864 mm (0.034 inch), 0.889 mm (0.035 inch), 0.940 mm (0.037 inch), or 0.991 mm (0.039 inch). The thickness of the back wall 3921 can help distribute stress and increase the bending of the strikeface 3712.

[0153] In some embodiments, the maximum height of the back wall 3921 of the upper region 3711, measured perpendicular to a ground plane 3903 when golf club head 3700 is at address, to first inflection point 3986, can range from 0.635 cm (0.25 inch) to 7.62 cm (3 inches), or 1.27 cm (0.50 inch) to 5.08 cm (2 inches). For example, the first inflection point 3986 can be 0.635 cm (0.25 inch), 0.953 cm (0.375 inch), 1.27 cm (0.5 inch), 1.59 cm (0.625 inch), 1.91 cm (0.75 inch), 2.10 cm (0.825 inch), 2.54 cm (1.0 inch), 2.88 cm (1.125 inches), 3.18 cm (1.25 inches), 3.49 cm (1.375 inches), 3.81 cm (1.5 inches), 4.12 cm (1.625 inches), 4.45 cm (1.75 inches), 4.76 cm (1.875 inches), 5.08 cm (2.0 inches), 5.40 cm (2.125 inches), 5.71 cm (2.25 inches), 6.03 cm (2.375 inches), 6.35 cm (2.5 inches), 6.67 cm (2.625 inches), 7.00 cm (2.75 inches), 7.30 cm (2.875 inches) or 7.62 cm (3.0 inches) above a lowest point of sole 3706 to the ground plane 3903 when golf club head 3700 is at address.

[0154] In many embodiments, second inflection point 3992 of cavity 3730 of upper region 3711, adjacent to bottom incline 3925 of lower region 3713, can have a distance from apex 3928 of top rail 3715 ranging from at least 0.635 cm (0.25 inch) to 5.08 cm (2.0 inches), or 1.27 cm (0.5 inch) to 3.81 cm (1.5 inches). For example, the second inflection point 3992 can be at least 0.635 cm (0.25 inch), 1.27 cm (0.5 inch), 1.91 cm (0.75 inch), 2.53 cm (1.0 inch), 3.18 cm (1.25 inches), 4.45 cm (1.75 inches), or 5.08 cm (2.0 inches) below the apex 3928 of top rail 3715.

[0155] In some embodiments as illustrated in FIG. 23, cavity 3730 of upper region 3711 can comprise at least one channel 3739. In many embodiments, channel 3739 extends from heel region 3702 to toe region 3704. Channel 3739 comprises a channel width 3932 measured from back wall 3921 to the second reference point 3982 substantially parallel to ground plane 3903, where channel width can vary in a direction from top rail 3215 to sole 3206. In some embodiments as illustrated in FIG. 23, channel width 3932 can range from 1 mm (0.039 inch) to 15 mm (0.590 inch), or 3.81 mm (0.150 inch) to 10.16 mm (0.400 inch). For example, channel width 3932 can be 1.0 mm (0.039 inch), 2 mm (0.079 inch), 3 mm (0.12 inch), 4 mm (0.16 inch), 5 mm (0.20 inch), 6 mm (0.24 inch), 7 mm (0.28 inch), 8 mm (0.31 inch), 10 mm (0.39 inch), or 15 mm (0.59 inch). In other embodiments, a channel toe region width of channel 3739 is less than a channel heel region width of channel 3739. In other embodiments, the channel heel region width is less than the channel toe region width. In other embodiments, a channel middle region width of channel 3739 can be less than at least one of the channel heel region width or the channel toe region width. In other embodiments, the channel middle region width can be greater than at least one of the channel heel region width or the channel toe region width. In some embodiments, channel 3739 is symmetrical from heel to toe. In other embodiments, channel 3739 is non-symmetrical. In other embodiments, channel 3739 can further comprise at least toe partial channels. In some embodiments, channel 3739 can comprise a series of partial channels interrupted by one or more bridges. In some embodiments, the one or more bridges can be approximately the same thickness as the thickness of top rail 3715.

[0156] Channel width 3932, as described herein, allows absorption of stress from strikeface 3712 on impact. A golf club head having a channel width less than the channel width 3932 described here (e.g., a golf club head with a less pronounced cavity) would allow less stress absorption from the strikeface on impact (due to less material on the upper region 3711 of rear 3710), and therefore would experience less strikeface deflection than golf club head 3700 described herein.

[0157] In many embodiments, back cavity 3730 further comprises a back cavity angle 3935. Back cavity angle 3935 is measured from reference line 3939 to top wall 3719. In many embodiments, back cavity angle 3935 can range from 5 degrees to 80 degrees. In some embodiments, back cavity angle 3935 can be 5 degrees, 10 degrees, 15 degrees, 20 degrees, 25 degrees, 30 degrees, 35 degrees, 40 degrees, 45 degrees, 50 degrees, 55 degrees, 60 degrees, 65 degrees, 70 degrees, 75 degrees, or 80 degrees.

[0158] In some embodiments, back wall 3921 of cavity 3730 of upper region 3711 can further comprise a planar surface. In other embodiments, at least a portion of back wall 3921 can comprise a protrusion 3940 extending outward, away from strike face 3712. At least a portion of back wall 3921 comprising protrusion 3940 can range from 15% to 100%. For example, at least 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75 %, 80%, 85%, 90%, 95%, or 100% of back wall 3921 can comprise protrusion 3940. Protrusion 3940 can be positioned on at least a portion of back wall 3921 closer to toe region 3704, closer to heel region 3702, closer to lower exterior wall 3927, closer to top wall 3719, or centered on the back wall 3921. Protrusion 3940 comprises a length 3942, measured from heel region 3702 to toe region 3704, and a width 3944, measured from top rail 3715 to sole 3706.

[0159] The protrusion 3940 can comprise a thickness measured perpendicularly from the interior surface 3919 to the exterior surface 3703 of the protrusion 3940. The thickness of the protrusion 3940 can range from 0.711 mm (0.028 inch) to 1.143 mm (0.045 inch), 0.711 mm (0.028 inch) to 0.813 mm (0.032 inch), 0.813 mm (0.032 inch) to 0.991 mm (0.039 inch), or 0.991 mm (0.039 inch) to 1.143 mm (0.045 inch). For example, the thickness of the back wall 3921 can be 0.711 mm (0.028 inch), 0.762 mm (0.030 inch), 0.813 mm (0.032 inch), 0.864 mm (0.034 inch), 0.889 mm (0.035 inch), 0.940 mm (0.037 inch), 0.991 mm (0.039 inch), 1.041 mm (0.041 inch), 1.092 mm (0.043 inch), or 1.143 mm (0.045 inch). The thickness of the protrusion 3940 can help distribute stress and increase the bending of the strikeface 3712.

[0160] FIG. 26 illustrates a view of top rail 3715 and a portion of rear 3710 of the cross-section of golf club head 3700 of FIG. 23, along a cross-sectional line XXXIX-XXXIX in FIG. 23 that is similar to the cross-section of FIG. 25. In many embodiments, golf club head 3700 comprises a rear angle 4040, a top rail angle 4045, and a strikeface angle 4050. Rear angle 4040 is measured from top wall 3719 to rear wall 3923 of upper region 3711. In many embodiments, rear angle 4040 can range from 70 degrees to 140 degrees. In some embodiments, rear angle 4040 can be 70 degrees, 75 degrees, 80 degrees, 85 degrees, 90 degrees, 100 degrees, 105 degrees, 110 degrees, 115 degrees, 120 degrees, 125 degrees, 130 degrees, 135 degrees, or 140 degrees. Top rail angle 4045 is measured from rear wall 3923 of upper region 3711 to top rail 3715. In many embodiments, top rail angle 4045 can range from 35 degrees to 120 degrees or 70 degrees to 110 degrees. In some embodiments, top rail angle 4045 can be 35 degrees, 40 degrees, 45 degrees, 50 degrees, 55 degrees, 60 degrees, 65 degrees, 70 degrees, 75 degrees, 80 degrees, 85 degrees, 90 degrees, 95 degrees, 100 degrees, 105 degrees, 110 degrees, 115 degrees, or 120 degrees. Strikeface angle 4050 is measured from strikeface 3712 to top rail 3715. In many embodiments, strikeface angle 4050 can range from 70 degrees to 160 degrees or 70 degrees to 110 degrees. In some embodiments, strikeface angle 4050 can be 70 degrees, 75 degrees, 80 degrees, 90 degrees, 95 degrees, 100 degrees, 105 degrees, 110 degrees, 115 degrees, 120 degrees, 125 degrees, 130 degrees, 135 degrees, 140 degrees, 145 degrees, 150 degrees, 155 degrees, or 160 degrees.

[0161] The upper region 3711 further comprises a minimum gap 4090 measured as a perpendicular distance from an inner surface of the cavity at the first inflection point 3986 to the inner surface 3919 of strikeface 3712. In some embodiments, minimum gap 4090 can range from 2 mm (0.079 inch) to 6 mm (0.24 inch). For example, minimum gap 4090 can be 2 mm (0.079 inch), 3 mm (0.118 inch), 4 mm (0.16 inch), 5 mm (0.197 inch) or 6 mm (0.24 inch). In other embodiments, minimum gap 4090 can range from 3 mm (0.118 inch) to 4 mm (0.16 inch). In some embodiments, minimum gap 4090 can be 3.429 mm (0.135 inch).

[0162] Lower region 3713 of rear 3710 of body 3701 comprises the bottom incline 3925, and a lower exterior wall 3927. The lower exterior wall 3927 is located below and adjacent the bottom incline 3925. A third inflection point 3994 is located between the bottom incline 3925 and the lower exterior wall 3927. A third reference point 3920 is located between lower exterior wall 3927 and sole 3706.

[0163] A top portion of the lower exterior wall 3927 of the lower region 3713 can comprise a thickness. The thickness of the top portion of the lower exterior wall 3927 can be measured perpendicular from the interior surface 3919 to the exterior surface 3703 of the top portion of the lower exterior wall 3927. The thickness of the top portion of the lower exterior wall 3827 can range from 0.94 mm (0.037 inch) to 1.47 mm (0.058 inch), 0.94 mm (0.037 inch) to 1.22 mm (0.048 inch), or 1.07 mm (0.042 inch) to 1.47 mm (0.058 inch). For example, the thickness of the top portion of the lower exterior wall 3827 can be 0.94 mm (0.037 inch), 1.02 mm (0.040 inch), 1.09 mm (0.043 inch), 1.17 mm (0.046 inch), 1.24 mm (0.049 inch), 1.32 mm (0.052 inch), 1.40 mm (0.055 inch), or 1.47 mm (0.058 inch). The thickness of the top portion of the lower exterior wall 3827 can aid in stress distribution as well as increase the bending of the strikeface 3712.

[0164] . In some embodiments, bottom incline 3925 of lower region 3713 comprises a bottom incline length 3929. Bottom incline length 3929 is measured from second inflection point 3992 to the third inflection point 3994. In a number of embodiments, bottom incline length 3994 can range from 0.025 cm (0.010 inch) to 0.533 cm (0.210 inch), 0.025 cm (0.010 inch) to 0.127 cm (0.050 inch), 0.127 cm (0.050 inch) to 0.254 cm (0.100 inch), 0.254 cm (0.100 inch) to 0.381 cm (0.150 inch), or 0.381 cm (0.150 inch) to 0.533 cm (0.210 inch). In many embodiments, bottom incline length 3929 can be 0.025 cm (0.010 inch), 0.076 cm (0.030 inch), 0.127 cm (0.050 inch), 0.178 cm (0.070 inch), 0.229 cm (0.090 inch), 0.279 cm (0.110 inch), 0.330 cm (0.130 inch), 0.381 cm (0.150 inch), 0.406 cm (0.160 inch), 0.432 cm (0.170 inch), 0.457 cm (0.180 inch), 0.483 cm (0.190 inch), 0.508 cm (0.200 inch), or 0.533 cm (0.210 inch). In some embodiments, the bottom incline length 3929 can vary from heel region 3702 to toe region 3704. In other embodiments, the bottom incline length 3929 can remain constant from heel region 3702 to toe region 3704.

[0165] In some embodiments, the maximum height of bottom incline 3925, measured perpendicular from ground plane 3903 when body 3701 is at address, to second inflection point 3992, can be 0.635 cm (0.25 inches) to 7.62 cm (3 inches), 1.27 cm (0.05 inch) to 5.08 cm (2 inches) above ground 3903. For example, the second inflection point 3992 can be 0.635 cm (0.25 inch), 0.953 cm (0.375 inch), 1.27 cm (0.5 inch), 1.59 cm (0.625 inch), 1.91 cm (0.75 inch), 2.10 cm (0.825 inch), 2.54 cm (1.0 inch), 2.88 cm (1.125 inches), 3.18 cm (1.25 inches), 3.49 cm (1.375 inches), 3.81 cm (1.5 inches), 4.12 cm (1.625 inches), 4.45 cm (1.75 inches), 4.76 cm (1.875 inches), 5.08 cm (2.0 inches), 5.40 cm (2.125 inches), 5.71 cm (2.25 inches), 6.03 cm (2.375 inches), 6.35 cm (2.5 inches), 6.67 cm (2.625 inches), 7.00 cm (2.75 inches), 7.30 cm (2.875 inches), or 7.62 cm (3.0 inches) above ground 3903.

[0166] In some embodiments, lower region 3713 further comprises a lower angle 3951 measured from between the bottom incline 3925 of lower region 3713 and lower exterior wall 3927 of lower region 3710, as illustrated in FIG. 27. In some embodiments, lower angle 3951 can be less than 180 degrees. In a number of embodiments, lower angle 3951 can be 30 degrees to 160 degrees, or 70 degrees to 130 degrees. For example, lower angle 3951 can be 30 degrees, 40 degrees, 50 degrees, 60 degrees, 70 degrees, 80 degrees, 90 degrees, 100 degrees, 110 degrees, 120 degrees, 130 degrees, 140 degrees, 150 degrees, or 160 degrees.

[0167] In some embodiments, lower region 3713 further comprises a bottom incline angle 3905 measured from bottom incline 3925 to ground 3903. Bottom incline angle 3905 can range from 15 degrees to 45 degrees. In some embodiments, bottom incline angle 3905 can be 15 degrees, 16 degrees, 17 degrees, 18 degrees, 19 degrees, 20 degrees, 21 degrees, 22 degrees, 23 degrees, 24 degrees, 25 degrees, 26 degrees, 27 degrees, 28 degrees, 29 degrees, 30 degrees, 31 degrees, 32 degrees, 33 degrees, 34 degrees, 35 degrees, 36 degrees, 37 degrees, 38 degrees, 39 degrees, 40 degrees, 41 degrees, 42 degrees, 43 degrees, 44 degrees, or 45 degrees.

[0168] FIG. 27 illustrates a simplified cross-sectional view of golf club head 3700, similar to the detailed cross-section of golf club head 3700 illustrated in FIG. 25. Golf club head 3700 includes cavity 3730, upper region 3711, lower region 3713, and exterior surface 3703. In many embodiments, a maximum upper distance 4192 measured as the perpendicular distance from the exterior surface 3703 of strikeface 3712 to the exterior surface 3703 of second reference point 3982 of upper region 3711 can range from 5 mm (0.20 inch) to 15 mm (0.59 inch). For example, maximum upper distance 4192 can be 5 mm (0.20 inch), 6 mm (0.24 inch), 7 mm (0.28 inch), 8 mm (0.31 inch), 8.89 mm (0.35 inch), 10 mm (0.39 inch), 11 mm (0.43 inch), 12 mm (0.47 inch), 13 mm (0.51 inch), 14 mm (0.55 inch), or 15 mm (0.59 inch). In some embodiments, maximum upper distance 4192 can be 9.09 mm (0.348 inch). Further, a minimum upper distance 4194 measured as the perpendicular distance from the exterior surface 3703 of strikeface 3712 to the exterior surface 3703 of the back wall 3921 at the first inflection point 3986 can range from 4 mm (0.16 inch) to 12 mm (0.47 inch). For example, minimum upper distance 4194 can be 4 mm (0.16 inch), 5 mm (0.20 inch), 6 mm (0.24 inch), 7 mm (0.28 inch), 8 mm (0.31 inch), 9 mm (0.35 inch), 10 mm (0.39 inch), 11 mm (0.43 inch), or 12 mm (0.47 inch). In some embodiments, minimum upper distance 4194 can be 7.85 mm (0.309 inch). Further still, a maximum lower distance 4196 measured as the perpendicular distance from the exterior surface 3703 of strikeface 3712 to the exterior surface 3703 of third reference point 3920 of lower region 3713 can range from 17 mm (0.670 inch) to 25 mm (0.98 inch). For example, maximum lower distance 4196 can be 17 mm (0.670 inch), 18 mm (0.709 inch), 19 mm (0.748 inch), 20 mm (0.787 inch), 21 mm (0.827 inch), 22 mm (0.866 inch), 23 mm (0.906 inch), 24 mm (0.945 inch), or 25 mm (0.98 inch). In some embodiments, maximum lower distance 4196 can be 21.9 mm (0.863 inch). In many embodiments, maximum lower distance 4196 is greater than maximum upper distance 4192 and maximum upper distance 4192 is greater than minimum upper distance 4194.

[0169] As illustrated in FIGS. 25-27, body 3701 is a hollow body club head that further comprises internal cavity 3716. Internal cavity 3716 of the body 3701 comprises a volume. The volume of the internal cavity 3716 can range from 11.47 cc (0.70 inch³) to 27.86 cc (1.70 inches³). In some embodiments, the internal cavity 3716 can comprise a volume of 11.47 cc (0.70 inch³), 13.11 cc (0.80 inch³), 14.75 cc (0.90 inch³), 16.39 cc (1.00 inch³), 18.03 cc (1.10 inches³), 19.66 cc (1.20 inches³), 21.30 cc (1.30 inches³), 22.94 cc (1.40 inches³), 24.58 cc (1.50 inches³), 26.22 cc (1.60 inches³), or 27.86 cc (1.70 inches³).

[0170] The internal cavity 3716 of the body 3701 further comprises interior surface 3919. In some embodiments, interior surface 3919 of rear 3710 is a planar and smooth surface. In other embodiments as illustrated in FIG. 28, the interior surface 3919 of the internal cavity 3716 of rear 3710 comprises a plurality of ribs 3952. The plurality of ribs 3952 extend in a direction from top rail 3715 toward sole 3706. Plurality of ribs 3952 can be located anywhere on interior surface 3919 of rear 3710. In some examples, plurality of ribs 3952 can be positioned onto a portion of interior surface 3919 of lower exterior wall 3927. In other examples, plurality of ribs 3952 can be position on a portion of interior surface 3919 of rear wall 3923. In some embodiments, plurality of ribs 3952 can be positioned on a portion of interior surface 3919 of rear 3710 and can extend into another portion of the rear 3710. For example, plurality of ribs 3952 are positioned on a portion of interior surface 3919 of rear wall 3923 and can extend up to at least a portion of the interior surface 3919 of top wall 3719, at least a portion of back wall 3921, or at least a portion of lower exterior wall 3927. The plurality of ribs 3952 can comprise between 1 to 8 ribs. For example, the plurality of ribs 3952 can comprise one rib 3952, two ribs 3952, three ribs 3952, four ribs 3952, five ribs 3952, six ribs 3952, seven ribs 3952, or eight ribs 3952. In embodiments having one or more plurality of ribs 3952, the plurality of ribs 3952 can be spaced equidistance from each other or more concentrated near heel region 3702, toe region 3704, top rail 3715, or sole 3706. The plurality of ribs 3952 and the location of the plurality of ribs 3952 can help optimize the frequency and amplitude of sound response.

[0171] In many embodiments, internal cavity 3716 of body 3701 can be void of any substances. In other embodiments, internal cavity 3716 of body 3701 can further comprise a polymer, wherein the polymer can at least partially fill the internal cavity 3716. The polymer can be polyethylene terephthalate, high-density polyethylene, polyvinyl chloride, polycarbonate, polypropylene, other thermoplastics, composite polymers or any combination thereof. The polymer can fill 10% to 80% 10% to 25%, 15% to 30%, 30% to 45%, 45% to 60%, 60% to 75%, 75% to 80%, 10% to 40%, 30% to 60%, or 40% to 80% of the internal cavity 3716 of the body 3701. For example, the polymer can fill 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, or 85% of the internal cavity 3716 of the body 3701. In some embodiments, the polymer fills 80% of the internal cavity 3716 of the body 3701.

[0172] The polymer comprises a specific gravity ranging from 0.5 to 4. For example, the specific gravity of the polymer can be 0.5, 1, 1.5, 2, 2.5, 3, 3.5, or 4. In some embodiments, the specific gravity of the polymer is proportional to the mass of the polymer, wherein 1 specific gravity of the polymer is equal to 1 gram, 2 specific gravity of the polymer is equal to 2 grams and etc. Similarly, in some embodiments, the volume of the polymer is proportional to the polymer specific gravity. For example, the ratio of polymer mass to polymer volume can be 1 g to 1 cc, 2 g to 2 cc, 3 g to 3 cc, or 4 g to 4 cc. However, in other embodiments, while the specific gravity of the polymer is proportional to the polymer mass, the volume does not correlate to the specific gravity. For example, the ratio of polymer mass to polymer volume can be 1 g to 1 cc, 2 g to 0 cc, 3 g to 1 cc, 4 g to 2 cc, 4 g to 3 cc, 3 g to 2 cc, 3 g to 4 cc, or any other suitable ratio.

[0173] The mass of the polymer allows for the swing weight of the golf club head 3700 to be customizable for each player. Increasing the volume of polymer, and thus the mass, increases the swing weight, while decreasing the volume of polymer decreases the swing weight. Having the appropriate swing weight for each individual player improves feel during a swing and can improve performance such as swing speed, swing path and this ball speed, and ball trajectory. The polymer can further increase the overall mass of the golf club head 3700 more toward the rear 3710 and sole 3706. Increasing the mass more toward the rear 3710 and sole 3706 can keep the center of gravity low and back, and there improve the moment of the inertia. The polymer can further still act as a dampener to improve sound and absorb shock during impact.

[0174] . The polymer volume when filled within the internal cavity 3716 can range from 0 to 25 cc (0 inch³ to 1.53 inch³), 4 to 20 cc (0.244 inch³ to 1.22 inch³), 5 to 15 cc (0.305 inch³ to 0.915 inch³), 2 to 12 cc (0.122 inch³ to 0.488 inch³), or 14 to 22 cc (0.854 inch³ to 1.34 inch³). In some embodiments, the polymer volume inside the internal cavity 3716 can be 0 cc (0 inch³), 4 cc (0.244 inch³), 8 cc (0.244 inch³), 12 cc (0.488 inch³), 16 cc (0.976 inch³), 20 cc (1.22 inch³), or 25 cc (1.53 inch³). The polymer filled within the internal cavity 3716 can cover a percentage of the interior surface 3919 of the strikeface 3712 ranging from 0 % to 100%, 15% to 85%, 30% to 70%, 45% to 60%, 20% to 40%, or 60% to 80%. In some embodiments, the polymer covers 0%, 15%, 30%, 45%, 60%, 75%, 90% or 100% of the interior surface 3919 of the strikeface 3712. Increasing the percent coverage of the polymer on the interior surface 3919 of the strikeface 3712 increases the support for the strikeface 3712, thereby allowing for a thinner strikeface 3712. Thinning the strikeface 3712 can increase the deflection of the strikeface 3712 upon impact with a ball which can impart the ball with increases speed and spin. Thinning the strikeface 3716 also allows for weight to be redistributed elsewhere on the body 3701 to optimize center of gravity and moment of inertia.

[0175] In some embodiments as illustrated in FIG. 29, the golf club head 3700 can further comprise a first aperture 3934 located on toe region 3704 and a second aperture 3936 located in a hosel of the golf club head 3700. The first aperture 3924 is configured to receive a toe weight (not pictured), wherein the toe weight can range from 2 grams to 7 grams. In some embodiments, the toe weight can be 2 grams, 3 grams, 4 grams, 5 grams, 6 grams, or 7 grams. The second aperture 3936 is configured to receive a tip weight (not pictured), wherein the tip weight can range from 2 grams to 7 grams. In some embodiments, the tip weight can be 2 grams, 3 grams, 4 grams, 5 grams, 6 grams, or 7 grams. In many embodiments, the first aperture 3934 and the second aperture 3936 can further be configured to receive the polymer. The first aperture 3934 can receive 1 gram to 9 grams of polymer (e.g., 1 gram, 2 grams, 3 grams, 4 grams, 5 grams, 6 grams, 7 grams, 8 grams, or 9 grams). Similarly, the second aperture 3936 can receive 1 gram to 9 grams of polymer (e.g., 1 gram, 2 grams, 3 grams, 4 grams, 5 grams, 6 grams, 7 grams, 8 grams, or 9 grams). The toe and tip weight, and the polymer housed within the first aperture 3934 and the second aperture 3936 can affect the swing weight to optimize CG and MOI.

[0176] In many embodiments, cavity 3730 can provide an increase in golf ball speed over golf club head 1200, or other standard golf club heads, can reduce the spin rate of standard hybrids club heads, and can increase the launch angle over both the standard hybrid and iron club heads. In many embodiments, the shape of cavity 3730 determines the level of spring and timing of the response of golf club head 3200. When the golf club ball impacts strikeface 3712 of club head 3700 with cavity 3730, strikeface 3712 springs back like a drum, and a rear 3710 bends in a controlled buckle manner. In many embodiments, top rail 3715 can absorb more stress over greater volumetric space than a top rail in a golf club head without cavity 3730. The length, depth and width of cavity 3730 can vary. These parameter provide control regarding how much spring back is present in the overall design of club head 3700.

[0177] Upon impact with the golf ball, strikeface 3712 can bend inward at a greater distance than on a golf club without cavity 3730. In some embodiments, strikeface 3712 has a 10% to a 50 % greater deflection than a strikeface on a golf club head without cavity 3730. In some embodiments, strikeface 3712 has a 5% to 40% or a 10% to a 20% greater deflection than a strikeface on a golf club head without cavity 3730. For example, strikeface 3712 can have a 5%, 10 %, 15%, 20%, 25%, 30%, 35%, or 40% greater deflection than a strikeface on a golf club head without cavity 3730. In many embodiments, there is both a greater distance of retraction by strikeface 3712 due to the hinge and bending of cavity 3730 over a standard strikeface that does not have a back portion of the club with the cavity.

[0178] In many embodiments, the face deflection is greater with club head 3700 having cavity 3730, as a greater buckling occurs at first inflection angle 3986 of top wall 3219 upon impact with a golf ball. Cavity 3730, however, provides a greater dispersion of stress along top rail 3715, rear wall 3923, and top wall 3719, and the spring back force is transferred from cavity 3730 and first inflection point 3986 of top wall 3719 to strikeface 3712. A standard top rail, rear wall and top wall without a cavity does not have this hinge/buckling effect, nor does it absorb a high level of stress over a large volumetric area of the top rail, rear wall and top wall. Therefore, the standard strikeface does not contract and then recoil as much as strikeface 3712. Further, both a larger region of strikeface 3712, top rail 3715, rear wall 3923, and top wall 3719 absorb more stress than the same crown region of a standard golf club head with a standard top rail, top wall and no cavity. In many embodiments, although there is greater stress along a greater area above cavity 3730 that the same area in a standard club without the cavity, the durability of the club head with and without the cavity is the same. By adding more spring to the back end of the club (due to inward inclination of a portion of top wall 3719 toward strikeface 3712), more force is displaced throughout the volume of the structure. The stress is observed over a greater area of strikeface 3712, top rail 3715, rear wall 3923, and top wall 3719 of golf club head 3700. Peak stresses can be seen in the standard top rail club head. However, more peak stresses are seen in golf club head 3700 but distributed over a large volume of the material. The hinge and bend regions of golf club head 3700 (i.e., the region above cavity 3730 and cavity 3730 itself) will not deform as long as the stress does not meet the critical buckling threshold. Cavity 3730 and its placement can be designed to be under the critical K value of the buckling threshold.

[0179] As shown in FIG. 28, a further deflection feature of the golf club head 3700 can be the uniform thinned region 4160, located at the sole 3706 and stretching between the rear 3710 of the body 3701 and the strikeface 3712, toward a cascading sole portion of the sole (as described in greater detail below). The uniform thinned region 4160 can provide multiple benefits. First, the uniform thinned region 4160 can reduce stress on the strikeface 3712 caused during impact with the golf ball. Second, the uniform thinned region 4160 can bend allowing the strikeface 3712 to experience greater deflection. Third, the uniform thinned region 4160 removes weight from the sole area, allowing the weight to be redistributed more toward the rear of the golf club head 3700. At impact, the energy imparted to the strikeface 3712 by the golf ball can cause the uniform thinned region to bend outward, which in turn increases the strikeface 3712 deflection. After bending, the uniform thinned region 4160 rebounds back to its original position returning the majority of the energy from impact back to the golf ball. The result is the golf club head 3700 imparts increased ball speeds and greater travel distances to the golf ball after impact.

[0180] In some embodiments, body 3701 can comprise stainless steel, titanium, aluminum, a steel alloy (e.g. 455 steel, 475 steel, 431 steel, 17-4 stainless steel, maraging steel), a titanium alloy (e.g. Ti 7-4, Ti 6-4, T-9S, Ti SSAT2041, Ti SP700, Ti 15-0-3, Ti 15-5-3, Ti 3-8-6-4-4, Ti 10-2-3, Ti 15-3-3-3, Ti-6-6-2, Ti-185, or any combination thereof), an aluminum alloy, or a composite material. In other embodiments, body 3701 can comprise carpenter grade 455 steel, carpenter grade 475 steel, C300 steel, C350 steel, a Ni-Co-Cr steel alloy, a quench and tempered steel alloy, or 565 steel. In some embodiments, strikeface 3712 can comprise stainless steel, titanium, aluminum, a steel alloy (e.g. 455 steel, 475 steel, 431 steel, 17-4 stainless steel, maraging steel), a titanium alloy (e.g. Ti 7-4, Ti 6-4, T-9S, Ti SSAT2041, Ti SP700, Ti 15-0-3, Ti 15-5-3, Ti 3-8-6-4-4, Ti 10-2-3, Ti 15-3-3-3, Ti-6-6-2, Ti-185, or any combination thereof), an aluminum alloy, or a composite material. In other embodiments, strikeface 3712 can comprise carpenter grade 455 steel, carpenter grade 475 steel, C300 steel, C350 steel, a Ni-Co-Cr steel alloy, a quench and tempered steel alloy, or 565 steel. In some embodiments, body 3701 can comprise the same material as strikeface 3712. In some embodiments, body 3701 can comprise a different material than strikeface 3712.

[0181] FIG. 30 illustrates a back perspective view of an embodiment of golf club head 4400 and FIG. 31 illustrates a back heel-side perspective view of golf club head 4400 according to the embodiment of FIG. 30. In some embodiments, golf club head 4400 can be similar to golf club head 1000 (FIG. 1), golf club head 2200 (FIG. 8), golf club head 2700 (FIG. 13), golf club head 3200 (FIG. 18), and/or golf club head 3700 (FIG. 23). Golf club head 4400 can be an iron-type golf club head. In other embodiments, golf club head 4400 can be a hybrid-type, or a fairway wood-type golf club head. In some embodiments, golf club head 4400 does not comprise a badge or a custom tuning port.

[0182] Golf club head 4400 comprises a body 4401. In some embodiments, body 4401 can be similar to body 1001 (FIG. 1), body 2201 (FIG. 8), body 2701 (FIG. 13), body 3201 (FIG. 18), and/or body 3701 (FIG. 23). Body 4401 further comprises an exterior surface 4403, a strikeface 4412, a heel region 4402, a toe region 4404 opposite the heel region 4402, a sole 4406, a top rail 4415, and a rear 4410.

[0183] Body 4401 of FIGS. 44-48 further comprises a blade length. The blade length for body 4401 can be measured similar to blade length 3725 as shown and described in FIG. 29 (i.e., a measurement parallel to the flat surface of the strikeface 3712, from a toe edge 3726 of the strikeface 3712, to strikeface end 3727 before the strikeface 3712 integrally curves into the hosel). The blade length of the body 4401 can range from 6.35 cm (2.50 inches) to 7.37 cm (2.90 inches). For example, in some embodiments, the body 3701 can comprise a blade length of 6.35 cm (2.50 inch), 6.45 cm (2.54 inch), 6.55 cm (2.58 inch), 6.65 cm (2.62 inch), 6.76 cm (2.66 inch), 6.86 cm (2.70 inch), 6.96 cm (2.74 inch), 7.06 cm (2.78 inch), 7.16 cm (2.82 inch), 7.264 cm (2.86 inch), or 7.37 cm (2.90 inch).

[0184] As shown in FIG. 34, a further deflection feature of the golf club head 4400 can be the uniform thinned region 4860, located at the sole 4406 and stretching between the rear 4410 of the body 4401 and the strikeface 4412, toward a cascading sole portion of the sole (as described in greater detail below). In the illustrated embodiment, the uniform thinned region 4860 comprises a sole thickness measured perpendicular from the exterior surface 4403 to an interior surface 4619 at the uniform thinned region 4860, which can remain constant from the bottom of the strikeface 4412 to adjacent the cascading sole portion of the sole. In some embodiments, the sole thickness of the uniform thinned region 4860 can be thinner than a conventional sole. For example, in some embodiments, the sole thickness of the uniform thinned region 4860 may range from approximately 1.02 mm to 2.03 mm (0.040 inch to 0.080 inch). In other embodiments, the sole thickness of the uniform thinned region 4860 may be within the range of 1.02 mm to 1.27 mm (0.040 inch to 0.050 inch), 1.27 mm to 1.52 mm (0.050 inch to 0.060 inch), 1.52 mm to 1.78 mm (0.060 inch to 0.070 inch), 1.78 mm to 2.03 mm (0.070 inch to 0.080 inch), 1.02 mm to 1.40 mm (0.040 inch to 0.055 inch), 1.14 mm to 1.52 mm (0.045 inch to 0.060 inch), 1.27 mm to 1.65 mm (0.050 inch to 0.065 inch), 1.40 mm to 1.78 mm (0.055 inch to 0.070 inch), 1.52 mm to 1.90 mm (0.060 inch to 0.075 inch), or 1.65 mm to 2.03 mm (0.065 inch to 0.080 inch). For example, the sole thickness of the uniformed thinned region 4860 can be 1.02 mm (0.040 inch), 1.14 mm (0.045 inch), 1.27 mm (0.050 inch), 1.52 mm (0.060 inch), 1.65 mm (0.065 inch), 1.78 mm (0.070 inch), 1.90 mm (0.075 inch), or 2.03 mm (0.080 inch).

[0185] FIG. 32 illustrates a cross-section of golf club head 4400 along the cross-sectional line XLVI-XLVI in FIG. 30, according to one embodiment. As seen in FIG. 32, strikeface 4412 comprises a high region 4676, a middle region 4674, and a low region 4672.

[0186] The strikeface 4412 of the body 4401 further comprises a thickness 4654 measured perpendicularly to the strikeface 4412 from the exterior surface 4403 to an interior surface 4619. The thickness 4654 of the strikeface 4412 can range from 1.02 mm (0.040 inch) to 2.54 mm (0.100 inch). For example, the thickness 4654 of the strikeface 4412 can be 1.02 mm (0.040 inch), 1.14 mm (0.045 inch), 1.27 mm (0.050 inch), 1.40 mm (0.055 inch), 1.52 mm (0.060 inch), 1.65 mm (0.065 inch), 1.78 mm (0.070 inch), 1.91 mm (0.075 inch), 2.03 mm (0.080 inch), 2.16 mm (0.085 inch), 2.29 mm (0.090 inch), 2.41 mm (0.095 inch), or 2.54 mm (0.100 inch). In some embodiments, thickness 4654 of the strikeface 4412 can vary from the heel region 4402 to the toe region 4404, and/or from the top rail 4415 to the sole 4406. For example, the thickness 4654 of the strikeface 4412 can be greatest at the central portion near the middle region 4674 of the strikeface 4412, and taper along the periphery near the high region 4676 and the low region 4672 of strikeface 4412. In many embodiments, the center of the strikeface 4412 can have a thickness 4654 of 2.29 mm (0.090 inch) and the periphery of the strikeface 4412 can have a thickness 4654 of 1.78 mm (0.070 inch). In other examples, the thickness 4654 can increase, decrease, or any variation thereof starting at the central region near the middle region 4674 of the strikeface 4412 and extending toward the periphery near the high region 4676 and the low region 4672.

[0187] The cross-section of golf club head 4400 in FIG. 32 further illustrates the rear 4410. The rear 4410 can comprise an upper region 4411, a lower region 4413, and an inflection point 4686 disposed between the upper region 4411 and the lower region 4413. The inflection point 4686 is further located at the junction between the rear wall 4623 and the bottom incline 4625. The inflection point 4686 is located nearer to the sole of the club head than the top rail 4415.

[0188] The upper region 4411 of rear 4410 comprises a top rail 4415, an apex 4628 of top rail, a rear wall 4623 orientated parallel to the strikeface 4412, and a first reference point 4622 disposed between the top rail 4415 and the rear wall 4623. The first reference point 4622 is located at the junction between the top rail 4415 and the rear wall 2623 parallel to the strikeface 4412. In many embodiments, the rear wall 4623 of upper region 4411 is located below and adjacent the top rail 4415.

[0189] In some embodiments, top rail 4415 of the upper region 4411 can be a flatter and taller top rail or skirt than in irons known to one skilled in the art. The flatter and taller rail can compensate for mishits or strikeface 4412 to increase playability off the tee. In some embodiments. The length of top rail 4415, measured from heel region 4402 to toe region 4404, can be 70% to 95% of the length of the golf club head 4400.

[0190] The top rail 4415 of the upper region 4411 comprises a thickness 4652. The thickness 4652 of the top rail 4415 can range from 1.02 mm (0.040 inch) to 2.03 mm (0.080 inch). For example, the thickness 4652 of the top rail 4415 can be 1.02 mm (0.040 inch), 1.09 mm (0.043 inch), 1.17 mm (0.046 inch), 1.24 mm (0.049 inch), 1.30 mm (0.051 inch), 1.37 mm (0.054 inch), 1.45 mm (0.057 inch), 1.52 mm (0.060 inch), 1.60 mm (0.063 inch), 1.68 mm (0.066 inch), 1.75 mm (0.069 inch), 1.80 mm (0.071 inch), 1.88 mm (0.074 inch), 1.96 mm (0.077 inch), or 2.03 mm (0.080 inch). In many embodiments, the thickness 4652 of the top rail 4415 is constant throughout. In other embodiments, the thickness 4652 of the top rail 4415 can vary. In the exemplary embodiment, the thickness 4652 of the top rail 4415 decreases from the strikeface 4412 toward the rear wall 4623. In many embodiments due to the thickness 4652 of the top rail, top rail 4415 can provide an increase in the overall bending of strikeface 4412. In some embodiments, the bending of strikeface 4412 can allow for a 2% to 5% increase of energy.

[0191] FIG. 33 illustrated the top rail 4415 and a portion of the rear 4410 of the cross-section of the golf club head 4400 of FIG. 32, different from cross-section of golf club head 1200 as shown in FIG. 4. The strike face 4412 further comprises a strikeface angle 4750. Strikeface angle 4750 is measured from the strikeface 4412 to the top rail 4415, wherein the strikeface angle 4750 can range from 70 degrees to 160 degrees or 70 degrees to 110 degrees. In some embodiments, strikeface angle 4050 can be 70 degrees, 75 degrees, 80 degrees, 90 degrees, 95 degrees, 100 degrees, 105 degrees, 110 degrees, 115 degrees, 120 degrees, 125 degrees, 130 degrees, 135 degrees, 140 degrees, 145 degrees, 150 degrees, 155 degrees, or 160 degrees.

[0192] FIG. 33 further illustrates the top rail 4415 comprising a top rail angle 4745. The top rail angle 4745 is measured from rear wall 4623 to the top rail 4415. In many embodiments, the top rail angle 4745 can range from 35 degrees to 120 degrees or 70 degrees to 110 degrees. In some embodiments, top rail angle 4745 can be 35 degrees, 40 degrees, 45 degrees, 50 degrees, 55 degrees, 60 degrees, 65 degrees, 70 degrees, 75 degrees, 80 degrees, 85 degrees, 90 degrees, 95 degrees, 100 degrees, 105 degrees, 110 degrees, 115 degrees, or 120 degrees.

[0193] The rear wall 4623 of the upper region 4411 comprises a height 4680. The height 4680 of the rear wall 4623 is measured from the first reference point 4622 to the inflection point 4686, wherein the first reference point 4622 is positioned at the junction between the top rail 4415 and the rear wall 4623 parallel to the strikeface 4412. The height 4680 of the rear wall 4623 can range from 1.40 mm to 1.52 mm (0.055 inch to 0.060 inch), 1.52 mm to 1.78 mm (0.060 inch to 0.070 inch), 1.78 mm to 2.03 mm (0.070 inch to 0.080 inch), 2.03 mm to 2.16 mm (0.080 inch to 0.085 inch), or 13.97 mm to 21.59 mm (0.55 inch to 0.85 inch). For example, the height 4680 of the rear wall 4623 can be 13.97 mm (0.55 inch), 14.73 mm (0.58 inch), 15.49 mm (0.61 inch), 16.26 mm (0.64 inch), 17.02 mm (0.67 inch), 17.78 mm (0.70 inch), 18.54 mm (0.73 inch), 19.30 mm (0.76 inch), 20.07 mm (0.79 inch), 20.83 mm (0.82 inch), or 21.59 mm (0.85 inch). In some embodiments, the height 4680 of the rear wall 4623 can range from 35% to 60%, 35% to 45%, 45% to 68%, 40% to 55%, 30% to 40%, 35% to 45%, 40% to 50 %, 45% to 55%, or 50% to 60% of the total height of the golf club head 4400. For example, the height 4680 of the rear wall 4623 can be 35%, 38%, 41%, 44%, 47%, 50%, 53%, 56%, or 60% of the total height of the golf club head 4400.

[0194] The rear wall 4623 of the upper region 4411 can also comprise a height 4680A. The height 4680A is measured from the apex 4628 of the top rail 4415 to the inflection point 4686. The height 4680A can range from 15.24 mm to 25.4 mm (0.60 inch to 1.0 inch). For example, the height 4680A can be 15.24 mm (0.60 inch), 15.49 mm (0.61 inch), 16.26 mm (0.64 inch), 17.02 mm (0.67 inch), 17.78 mm (0.70 inch), 18.54 mm (0.73 inch), 19.30 mm (0.76 inch), 20.07 mm (0.79 inch), 20.83 mm (0.82 inch), 21.59 mm (0.85 inch), 22.86 mm (0.90 inch), 24.13 mm (0.95 inch), or 25.4 mm (1.0 inch). In some embodiments, the height 4680A can range from 40% to 75% of the total height of the golf club head 4400. For example, the height 4680A can be 40%, 44%, 47%, 50%, 53%, 56%, 60%, 65%, 70%, or 75% of the total height of the golf club head 4400.

[0195] The rear wall 4623 of the upper region 4411 further comprises a thickness 4656. The thickness 4656 is the perpendicular distance of the rear wall 4623 from the outer surface 4403 to the inner surface 4619. The thickness 4656 of the rear wall 4623 can range from 1.02 mm (0.040 inch) to 2.03 mm (0.080 inch). For example, the thickness 4656 of the rear wall 4623 can be 1.02 mm (0.040 inch), 1.09 mm (0.043 inch), 1.17 mm (0.046 inch), 1.24 mm (0.049 inch), 1.30 mm (0.051 inch), 1.37 mm (0.054 inch), 1.45 mm (0.057 inch), 1.52 mm (0.060 inch), 1.60 mm (0.063 inch), 1.68 mm (0.066 inch), 1.75 mm (0.069 inch), 1.80 mm (0.071 inch), 1.88 mm (0.074 inch), 1.96 mm (0.077 inch), or 2.03 mm (0.080 inch). In many embodiments, the thickness 4656 of the rear wall 4623 is constant throughout. In other embodiments, the thickness 4656 of the rear wall 4623 can vary. In the exemplary embodiment, the thickness 4656 of the rear wall 4623 is a constant 1.27 mm (0.05 inch). The thickness 4656 of the rear wall 4623 allows energy from an impact to transfer to the inflection point 4686 to help induce a buckling effect.

[0196] The lower region 4413 of the body 4401 comprises a bottom incline 4625, a lower exterior wall 4627, a second reference point 4682, and a third reference point 4620. The bottom incline 4625 is below and adjacent the inflection point 4686. The lower exterior wall 4627 is below and adjacent the bottom incline 4625. The second reference point 4682 is disposed between or positioned at the junction between the bottom incline 4625 and the lower exterior wall 4627. The third reference point 4620 is disposed between the lower exterior wall 4727 and the sole 4406. The bottom incline 4625 is angled away from the top rail 4415 and away from the strikeface 4412 in a direction toward the second reference point 4682.

[0197] In some embodiments, the bottom incline 4625 of the lower region 4413 comprises a bottom incline length 4629. The bottom incline length 4629 is measured from the inflection point 4686 to the second reference point 4682. The bottom incline length 4629 can range from 0 mm (0 inch) to 11.43 mm (0.45 inch). For example, the bottom incline length 4629 can be 0 mm (0 inch), 1.27 mm (0.05 inch), 2.54 mm (0.10 inch), 3.81 mm (0.15 inch), 5.08 mm (0.20 inch), 5.08 mm (0.20 inch), 6.35 mm (0.25 inch), 7.62 mm (0.30 inch), 8.89 mm (0.35 inch), 10.16 mm (0.40 inch), or 11.43 mm (0.45 inch). In some embodiments, the bottom incline length 4629 can remain constant from the heel region 4402 to the toe region 4404. In other embodiments, the bottom incline length 4629 can vary from the heel region 4402 to the toe region 4404. For example, the bottom incline length 4629 can increase from the heel region 4402 to the toe region 4404 as illustrated in FIG. 44. In other embodiments, the bottom incline length 4629 can decrease from the heel region 4402 to the toe region 4404.

[0198] In some embodiments, the lower region 4413 further comprises a lower angle 4651 measured from between the bottom incline 4625 to the lower exterior wall 4627. In some embodiments, the lower angle 4651 can be less than 180 degrees. In a number of embodiments, the lower angle 4651 can be 130 degrees to 175 degrees. For example, the lower angle 4651 of the lower region 4413 can be 130 degrees, 135 degrees, 140 degrees, 145 degrees, 150 degrees, 155 degrees, 160 degrees, 165 degrees, 170 degrees, or 175 degrees.

[0199] The upper region 4411 and the lower region 4413 of the rear 4410 is separated by the inflection point 4686. Due to the height 4680 of the rear wall 4623, the inflection point 4686 is positioned low on the body 4401. In many embodiments, the inflection point 4686 is positioned at least 40% down on the body 4401 below the apex 4628. For example, the inflection point 4686 can be positioned 40%, 42%, 44%, 46%, 48%, 50%, 52%, 54%, 56%, 58%, or 60% down on the body 4401 below the apex 4628. The low positioned inflection point 4686 allows for more leverage on the upper region 4411 to experience increased bending during impact with a ball, compared to a similar golf club head having a higher inflection point position.

[0200] The inflection point 4686 comprises an inflection angle 4696 measured from the rear wall 4623 of the upper region 4411, to the bottom incline 4625 of the lower region 4413. In some embodiments, the inflection angle 4696 can be measured from the rear wall 4623 to the lower exterior wall 4627 in the absence of the bottom incline 4625 (i.e., the bottom incline length 4629 is 0 cm (0 inch)). The inflection angle 4696 of the inflection point 4686 can range from at least 95 degrees to 150 degrees. In some embodiments, the inflection angle 4696 can be at least 95 degrees, 100 degrees, 105 degrees, 110 degrees, 115 degrees, 120 degrees, 125 degrees, 130 degrees, 135 degrees, 140 degrees, 145 degrees, or 150 degrees. In some embodiments, the inflection angle 4696 can be consistent from the heel region 4402 to the toe region 4404. In other embodiments, the inflection angle 4696 can vary from the heel region 4402 to the toe region 4404. In many embodiments, the inflection angle 4696 allows for inflection point 4686 to act as a buckling point or plastic hinge upon the golf club head 4400 impacting the golf ball at strikeface 4412. In other examples of a similar golf club head having an inflection angle, wherein the inflection angle is less than 95 degrees (i.e., 90 degrees, or the bottom incline is oriented approximately perpendicular to the strikeface), the inflection angle would impede energy transfer and prevent bending at the inflection point.

[0201] The inflection point 4686 further comprises a thickness 4660. The thickness 4660 of the inflection point 4686 is measured perpendicularly of the inflection point 4686 from the exterior surface 4403 to the interior surface 4619. The thickness 4660 of the inflection point 4686 can range from 1.02 mm (0.040 inch) to 2.03 mm (0.080 inch). For example, the thickness 4660 can be 1.02 mm (0.040 inch), 1.14 mm (0.045 inch), 1.27 mm (0.050 inch), 1.40 mm (0.055 inch), 1.52 mm (0.060 inch), 1.65 mm (0.065 inch), 1.78 mm (0.070 inch), 1.91 mm (0.075 inch), or 2.03 mm (0.080 inch). In many embodiments, the thickness 4660 at the inflection point 4686 is constant with the thickness 4656 of the rear wall 4623 and the thickness 4658 of the bottom incline 4625. In other embodiments, the thickness 4660 at the inflection point 4686 can be less than the thickness 4656 of the rear wall 4623 and the thickness 4658 of the bottom incline 4625. The thickness 4660 at the inflection point 4686 being consistent with or less than the thickness 4656, 4658 of the rear wall 4623 and the bottom incline 4625 allows for more uniform energy transfer and bending.

[0202] FIG. 34 illustrates another cross-sectional view of the golf club head 4400, similar to the detailed cross-section of golf club head 4400 illustrated in FIG. 30. The body 4401 of golf club head 4400 further comprises a minimum distance 4616, and a maximum distance 4618. The minimum distance of the body 4401 is measured as the perpendicular distance from the exterior surface 4403 of the strikeface 4412 in the upper region 4411 to the exterior surface 4403 of the rear wall 4623. The minimum distance 4616 can range from 5.08 mm (0.20 inch) to 10.16 mm (0.40 inch). For example, the minimum distance 4616 can be 5.08 mm (0.20 inch), 5.59 mm (0.22 inch), 6.10 mm (0.24 inch), 6.60 mm (0.26 inch), 7.11 mm (0.28 inch), 7.62 mm (0.30 inch), 8.13 mm (0.32 inch), 8.64 mm (0.34 inch), 9.14 mm (0.36 inch), 9.65 mm (0.38 inch), or 10.16 mm (0.40 inch). In some embodiments, the minimum distance 4616 of the body 4401 can be less than the bottom incline length 4629. The maximum distance 4618 of the body 4401 is measured as the perpendicular distance from the exterior surface 4403 of the strikeface 4412 in the lower region 4413 to the exterior surface 4403 of the third reference point 4620. The maximum distance 4618 can range from 15.24 mm (0.60 inch) to 22.86 mm (0.90 inch). For example, the maximum distance 4618 can be 15.24 mm (0.60 inch), 16.26 mm (0.64 inch), 17.27 mm (0.68 inch), 18.29 mm (0.72 inch), 19.30 mm (0.76 inch), 20.32 mm (0.80 inch), 21.34 mm (0.84 inch), 22.35 mm (0.88 inch), or 22.86 mm (0.90 inch).

[0203] As illustrated in FIG. 32-34, the golf club head 4400 can be a hollow, or at least partially hollow body comprising an internal cavity 4416. Internal cavity 4416 of the body 4401 comprises a volume. The volume of the internal cavity 4416 can range from 10.65 cm³ (0.65 inch³) to 17.21 cm³ (1.05 inch³). In some embodiments, the internal cavity 4416 can comprise a volume of 10.65 cm³ (0.65 inch³), 11.47 cm³ (0.70 inch³), 12.29 cm³ (0.75 inch³), 13.11 cm³ (0.80 inch³), 13.93 cm³ (0.85 inch³), 14.75 cm³ (0.90 inch³), 15.57 cm³ (0.95 inch³), 16.39 cm³ (1.00 inch³), or 17.21 cm³ (1.05 inch³). Similarly, the solid portion of the body 4401, void of the cavity 4416, further comprises a material volume. The material volume of the body 4401 can range from 40.97 cm³ (2.50 inch³) to 57.35 cm³ (3.50 inch³). For example, the material volume of the body 4401 can be 40.97 cm³ (2.50 inch³), 42.61 cm³ (2.60 inch³), 44.25 cm³ (2.70 inch³), 45.88 cm³ (2.80 inch³), 47.52 cm³ (2.90 inch³), 49.16 cm³ (3.00 inch³), 50.80 cm³ (3.10 inch³), 52.44 cm³ (3.20 inch³), 54.08 cm³ (3.30 inch³), 55.72 cm³ (3.40 inch³), or 57.35 cm³ (3.50 inch³).

[0204] In many embodiments, the internal cavity 4416 of the body 4401 can be void of any substance. In other embodiments, the internal cavity 4416 of the body 4401 can comprise a polymer (not pictured), wherein the polymer can be at least partially filling the internal cavity 4416. The polymer can be polyethylene terephthalate, high-density polyethylene, polyvinyl chloride, polycarbonate, polypropylene, other thermoplastics, composites polymers or any combination thereof. The polymer can fill 10% to 80% 10% to 25%, 15% to 30%, 30% to 45%, 45% to 60%, 60% to 75%, 75% to 80%, 10% to 40%, 30% to 60%, or 40% to 80% of the internal cavity 4416 of the body 4401. For example, the polymer can fill 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, or 85% of the internal cavity 4416 of the body 4401. In some embodiments, the polymer fills 80% of the internal cavity 4416 of the body 4401.

[0205] The polymer to at least partially fill the internal cavity 4416 of the body 4401 comprises a specific gravity ranging from 0.05 to 4. For example, the specific gravity of the polymer can be 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, or 4. In some embodiments, the specific gravity of the polymer is proportional to the mass of the polymer, wherein 1 specific gravity of the polymer is equal to 1 gram. Similarly, in those exemplary embodiments, the volume is proportional to the polymer specific gravity, wherein 1 specific gravity of the polymer is equal to 1 cc. In other embodiments, the volume is not proportional to the specific gravity of the polymer. For example, the ratio of the polymer specific gravity to the polymer volume can be 2:1 cc, 2:3 cc, 2:4 cc, 3:1 cc, 3:2 cc, 3:4 cc, 4:1 cc, 4:2 cc, or 4:3 cc.

[0206] The mass of the polymer allows for the swing weight of the golf club head 4400 to be customizable for each player. Increasing the volume of the polymer, and thus the mass, increases the swing weight. Similarly, decreasing the volume of the polymer decreases the swing weight. Having the appropriate swing weight for each individual player improves feel during a swing and can improve performance such as swing speed, swing path, ball speed, and ball trajectory. The polymer can further increase the overall mass of the golf club head 4400 more toward the sole 4406. Increasing the mass more toward the sole shifts the CG low and back, thereby improves the moment of inertia.

[0207] In some embodiments, the golf club head 4400 can further comprise an aperture (not pictured) located on the toe region 4404. The aperture comprises internal threads and is configured to receive a threaded screw weight (not pictured). The threaded screw weight comprises a mass, wherein the mass of the threaded screw weight can range from 2 grams to 12 grams. In other embodiments, the mass of the threaded screw weight can range from 4 grams to 10 grams. In some embodiments, the screw weight can be 2 grams, 3 grams, 4 grams, 5 grams, 6 grams, 7 grams, 8 grams, 9 grams, 10 grams, 11 grams, or 12 grams. The mass of the screw weight correlates with the length of the screw weight, wherein a longer threaded screw weight equates to a greater mass. The threaded screw weight further affects the mass and overall swing weight of the golf club head 4400. Therefore, the threaded screw weight can improve the feel of the golf club head 4400, as well as performance characteristics (e.g., swing speed, ball speed, and ball flight).

[0208] In many embodiments, the low positioning of the inflection point 4686 can provide an increase in golf ball speed over golf club head 1200 (or other standard golf club heads), can reduce the spin rate of standard hybrid club heads (or other standard golf club heads), and can increase the launch angle over both the standard hybrid and iron club heads. An inflection point positioned less than 40% down the body from the apex cannot buckle as easily because the high positioning decreases the leverage for the upper region to bend. Therefore, when the golf ball impacts strikeface 4412 of the club head 4400 with inflection point 4686 positioned at least 40% down the body 4401 from the apex 4628, the strikeface 4412 springs back like a drum, and the rear 4410 bends in a controlled buckle manner more than a golf club head having an inflection point positioned less than 40% down the body from the apex.

[0209] A standard top rail, and rear wall without a low positioned inflection point does not have this hinge/buckling effect, nor does it absorb a high level of stress over a large volumetric area of the top rail and rear wall. Therefore, the standard strikeface does not contract and then recoil as much as strikeface 4412. By adding more spring to the back end of the club (due to the thinness of the top rail 4415 and rear wall 4623, and the low position of the inflection point 4686), more force is displaced throughout the volume of the structure. The stress is observed over a greater area of strikeface 4412, top rail 4415, and rear wall 4623 of the golf club head 4400. Peak stresses can be seen in the typically just along the top rail in a standard club head. However, more peak stresses are seen in the golf club head 4400 but distributed over a large volume of the material. The hinge and bend regions of the golf club head 4400 (i.e., the inflection point 4686) will not deform as long as the stress does not meet the critical buckling threshold. Inflection point 4686 and its placement can be designed to be under the critical K value of the buckling threshold.

[0210] Further, upon impact with the golf ball, strikeface 4412 can bend inward at a greater distance than on a golf club without a thin top rail 4415, a thin rear wall 4623, and an inflection point 4686 positioned at least 40% down the body from the apex 4628. In some embodiments, the strikeface 4412 has a 10% to a 50% greater deflection than a strikeface on a golf club head without a thin top rail, a thin rear wall, and a low positioned inflection point. For example, the strikeface 4412 can have a 10%, a 15%, a 20%, a 30%, a 35%, a 40%, a 45%, or a 50% greater deflection than a strikeface of a golf club head without a thin top rail 4415, thin rear wall 4623, and low positioned inflection point 4686.

[0211] As shown in FIG. 34, a further deflection feature of the golf club head 4400 can be the uniform thinned region 4860, located at the sole 4406 and stretching between the rear 4410 of the body 4401 and the strikeface 4412, toward a cascading sole portion of the sole (as described in greater detail below). The uniform thinned region 4860 can provide multiple benefits. First, the uniform thinned region 4860 can reduce stress on the strikeface 4412 caused during impact with the golf ball. Second, the uniform thinned region 4860 can bend allowing the strikeface 4412 to experience greater deflection. Third, the uniform thinned region 4860 removes weight from the sole area, allowing the weight to be redistributed more toward the rear of the golf club head 4400. At impact, the energy imparted to the strikeface 4412 by the golf ball can cause the uniform thinned region 4860 to bend outward, which in turn increases the strikeface 4412 deflection. After bending, the uniform thinned region 4860 rebounds back to its original position returning the majority of the energy from impact back to the golf ball. The result is the golf club head 4400 imparts increased ball speeds and greater travel distances to the golf ball after impact.

[0212] In some embodiments, body 4401 can comprise stainless steel, , titanium, aluminum, a steel alloy (e.g. 455 steel, 475 steel, 431 steel, 17-4 stainless steel, maraging steel), a titanium alloy (e.g. Ti 7-4, Ti 6-4, T-9S, Ti SSAT2041, Ti SP700, Ti 15-0-3, Ti 15-5-3, Ti 3-8-6-4-4, Ti 10-2-3, Ti 15-3-3-3, Ti-6-6-2, Ti-185, or any combination thereof), an aluminum alloy, or a composite material. In other embodiments, body 4401 can comprise carpenter grade 455 steel, carpenter grade 475 steel, C300 steel, C350 steel, a Ni-Co-Cr steel alloy, a quench and tempered steel alloy, or 565 steel. In some embodiments, strikeface 4412 can comprise stainless steel, titanium, aluminum, a steel alloy (e.g. 455 steel, 475 steel, 431 steel, 17-4 stainless steel, maraging steel), a titanium alloy (e.g. Ti 7-4, Ti 6-4, T-9S, Ti SSAT2041, Ti SP700, Ti 15-0-3, Ti 15-5-3, Ti 3-8-6-4-4, Ti 10-2-3, Ti 15-3-3-3, Ti-6-6-2, Ti-185, or any combination thereof), an aluminum alloy, or a composite material. In other embodiments, strikeface 4412 can comprise carpenter grade 455 steel, carpenter grade 475 steel, C300 steel, C350 steel, a Ni-Co-Cr steel alloy, a quench and tempered steel alloy, or 565 steel. In some embodiments, body 4401 can comprise the same material as strikeface 4412. In some embodiments, body 4401 can comprise a different material than strikeface 4412.

[0213] FIG. 35 illustrates a back perspective view of an embodiment of a golf club head 4900, and FIG. 36 illustrates a back heel-side perspective view of the golf club head 4900 according to the embodiment of FIG. 35. In some embodiments, the golf club head 4900 can be similar to golf club head 1000 (FIG. 1), golf club head 2200 (FIG. 8), golf club head 2700 (FIG. 13), golf club head 3200 (FIG. 18), golf club head 3700 (FIG. 23), and/or golf club head 4400 (FIG. 30). The golf club head 4900 can be an iron-type golf club head. In some embodiments, the golf club head 4900 does not comprise a badge or a custom tuning port.

[0214] The golf club head 4900 comprises a body 4901. In some embodiments, the body 4901 can be similar to body 1001 (FIG. 1), body 2201 (FIG. 8), body 2701 (FIG. 13), body 3201 (FIG. 18), body 3701 (FIG. 23), and/or body 4401 (FIG. 30). The body 4901 further comprises an exterior surface 4903, a strikeface 4912, a heel region 4902, a toe region 4904 opposite the heel region, a sole 4906, a top rail 4915, and a rear 4910.

[0215] The body 4901 of FIGS. 49-52 further comprises a blade length. The blade length for the body 4901 can be measured similar to blade length 3725 as shown and described for golf club head 3700 in FIG. 43 (i.e., a measurement parallel to the flat surface of the strikeface, from a toe edge of the strikeface, to strikeface end before the strikeface integrally curves into the hosel). The blade length of the body 4901 can range from 6.35 cm (2.50 inches) to 7.37 cm (2.90 inches). In some embodiments, the blade length can range from 6.35 cm (2.50 inches) to 6.60 cm (2.60 inches), 6.60 cm (2.60 inches) to 6.86 cm (2.70 inches), 6.86 cm (2.70 inches) to 7.11 cm (2.80 inches), or 7.11 cm (2.80 inches) to 7.37 cm (2.90 inches). For example, in some embodiments, the body 4901 can comprise a blade length of 6.35 cm (2.50 inches), 6.45 cm (2.54 inches), 6.55 cm (2.58 inches), 6.65 cm (2.62 inches), 6.76 cm (2.66 inches), 6.86 cm (2.70 inches), 6.96 cm (2.74 inches), 7.06 cm (2.78 inches), 7.16 cm (2.82 inches), 7.264 cm (2.86 inches), or 7.37 cm (2.90 inches).

[0216] As shown in FIG. 39, a further deflection feature of the golf club head 4900 can be the uniform thinned region 5360, located at the sole 4906 and stretching between the rear 4910 of the body 4901 and the strikeface 4912, toward a cascading sole portion of the sole (as described in greater detail below). In the illustrated embodiment, the uniform thinned region 5360 comprises a sole thickness 5361 measured perpendicular from the exterior surface 4903 to an interior surface 5119 at the uniform thinned region 5360, which can remain constant from the bottom of the strikeface 4912 to adjacent the cascading sole portion of the sole 4906. In some embodiments, the sole thickness 5361 of the uniform thinned region 5360 can be thinner than a conventional sole. For example, in some embodiments, the sole thickness 5361 of the uniform thinned region 5360 may range from approximately 1.02 mm to 2.03 mm (0.040 inch to 0.080 inch). In other embodiments, the sole thickness 5361 of the uniform thinned region 5360 may be within the range of 1.02 mm to 1.27 mm (0.040 inch to 0.050 inch), 1.27 mm to 1.52 mm (0.050 inch to 0.060 inch), 1.52 mm to 1.78 mm (0.060 inch to 0.070 inch), 1.78 mm to 2.03 mm (0.070 inch to 0.080 inch), 1.02 mm to 1.40 mm (0.040 inch to 0.055 inch), 1.14 mm to 1.52 mm (0.045 inch to 0.060 inch), 1.27 mm to 1.65 mm (0.050 inch to 0.065 inch), 1.40 mm to 1.78 mm (0.055 inch to 0.070 inch), 1.52 mm to 1.90 mm (0.060 inch to 0.075 inch), or 1.65 mm to 2.03 mm (0.065 inch to 0.080 inch). For example, the sole thickness of the uniformed thinned region 5360 can be 1.02 mm (0.040 inch), 1.14 mm (0.045 inch), 1.27 mm (0.050 inch), 1.52 mm (0.060 inch), 1.65 mm (0.065 inch), 1.78 mm (0.070 inch), 1.90 mm (0.075 inch), or 2.03 mm (0.080 inch).

[0217] FIG. 37 illustrates a cross-section of the golf club head 4900, according to one embodiment. As seen in FIG. 37, the strikeface 4912 comprises a high region 5176, a middle region 5174, and a low region 5172.

[0218] The strikeface 4912 of the body 4901 further comprises a thickness 5154 measured perpendicular to the strikeface 4912 from the exterior surface 4903 to an interior surface 5119. The thickness 5154 of the strikeface 4912 can range from 1.02 mm (0.040 inch) to 5.08 mm (0.200 inch). In some embodiments, the thickness 5154 of the strikeface 4912 can range from 1.02 mm (0.040 inch) to 2.03 mm (0.080 inch), 2.03 mm (0.080 inch) to 3.05 mm (0.120 inch), 3.05 mm (0.120 inch) to 4.06 mm (0.160 inch), or 4.06 mm (0.160 inch) to 5.08 mm (0.200 inch). For example, the thickness 5154 of the strikeface 4912 can be 1.02 mm (0.040 inch), 1.14 mm (0.045 inch), 1.27 mm (0.050 inch), 1.40 mm (0.055 inch), 1.52 mm (0.060 inch), 1.65 mm (0.065 inch), 1.78 mm (0.070 inch), 1.90 mm (0.075 inch), 2.03 mm (0.080 inch), 2.16 mm (0.085 inch), 2.29 mm (0.090 inch), 2.41 mm (0.095 inch), 2.54 mm (0.100 inch), 3.81 mm (0.150 inch), or 5.08 mm (0.200 inch). In some embodiments, the thickness 5154 of the strikeface 4912 can vary from the heel region 4902 to the toe region 4904, and/or from the top rail 4915 to the sole 4906. For example, the thickness 5154 of the strikeface 4912 can be greatest at the central portion near the middle region 5174 of the strikeface 4912, and taper along the periphery near the high region 5176 and the low region 5172 of strikeface 4912. In many embodiments, the center of the strikeface 4912 can have a thickness 5154 range of 2.54 mm (0.10 inch) to 3.56 mm (0.14 inch), and the periphery of the strikeface 4912 can have a thickness 5154 range of 1.52 mm (0.06 inch) to 2.54 mm (0.10 inch). In some embodiments, the center of the strikeface 4912 can have a thickness 5154 range of 2.54 mm (0.10 inch) to 3.05 mm (0.12 inch), or 3.05 mm (0.12 inch) to 3.56 mm (0.14 inch). In other embodiments, the periphery of the strikeface 4912 can have a thickness 5154 range of 1.52 mm (0.06 inch) to 2.03 mm (0.08 inch), or 2.03 mm (0.08 inch) to 2.54 mm (0.10 inch). In other examples, the thickness 5154 can increase, decrease, or any variation thereof starting at the central region near the middle region of the strikeface and extending toward the periphery near the high region 5176 and the low region 5172.

[0219] The cross-section of the golf club head in FIG. 37 further illustrates the rear 4910. The rear 4910 can comprise an upper region 4911, a lower region 4913, and an inflection point 5186 disposed between the upper region 4911 and the lower region 4913. The inflection point 5186 is further located at the junction between the rear wall 5123 and the bottom incline 5125. The inflection point 5186 is located nearer to the sole 4906 of the club head 4900 than the top rail 4915.

[0220] The upper region 4911 of rear 4910 comprises a top rail 4915, an apex of top rail 5128, a rear wall 5123 orientated parallel to the strikeface 4912, and a first reference point 5122 disposed between the top rail 4915 and the rear wall 5123. The first reference point 5122 is located at the junction between the top rail 4915 and the rear wall 5123 parallel to the strikeface. In many embodiments, the rear wall 5123 of the upper region 4911 is located below and adjacent the top rail 4915.

[0221] In some embodiments, top rail 4915 of the upper region 4911 can be a flatter and taller top rail or skirt than in irons known to one skilled in the art. The flatter and taller rail can compensate for mishits or strikeface 4912 to increase playability off the tee. In some embodiments. The length of top rail 4915, measured from heel region 4902 to toe region 4904, can be 60% to 95% of the length of the golf club head 4900.

[0222] The top rail 4915 of the upper region 4911 comprises a thickness 5152. The thickness 5152 of the top rail 4915 can range from 1.02 mm (0.040 inch) to 2.03 mm (0.080 inch). In some embodiments, the thickness 5152 of the top rail 4915 can range from 1.02 mm (0.040 inch) to 1.52 mm (0.060 inch), or 1.52 mm (0.060 inch) to 2.03 mm (0.080 inch). For example, the thickness 5152 of the top rail 4915 can be 1.02 mm (0.040 inch), 1.09 mm (0.043 inch), 1.17 mm (0.046 inch), 1.24 mm (0.049 inch), 1.30 mm (0.051 inch), 1.37 mm (0.054 inch), 1.45 mm (0.057 inch), 1.52 mm (0.060 inch), 1.60 mm (0.063 inch), 1.68 mm (0.066 inch), 1.75 mm (0.069 inch), 1.80 mm (0.071 inch), 1.88 mm (0.074 inch), 1.96 mm (0.077 inch), or 2.03 mm (0.080 inch). In many embodiments, the thickness 5152 of the top rail 4915 is constant throughout. In other embodiments, the thickness 5152 of the top rail 4915 can vary. In the exemplary embodiment, the thickness 5152 of the top rail 4915 decreases from the strikeface 4912 toward the rear wall 5123. In many embodiments, due to the thickness of the top rail, top rail can provide an increase in the overall bending of strikeface. In some embodiments, the bending of strikeface can allow for a 2% to 5% increase of energy.

[0223] FIG. 38 illustrates the top rail 4915 and a portion of the rear 4910 of the cross-section of the golf club head of FIG. 35, different from cross-section of golf club head 1200 as shown in FIG. 4. The strikeface 4912 further comprises a strikeface angle 5250. The strikeface angle 5250 is measured from the strikeface 4912 to the top rail 4915, wherein the strikeface angle 5250 can range from 70 degrees to 160 degrees or 70 degrees to 110 degrees. In some embodiments, strikeface angle can be 70 degrees, 75 degrees, 80 degrees, 90 degrees, 95 degrees, 100 degrees, 105 degrees, 110 degrees, 115 degrees, 120 degrees, 125 degrees, 130 degrees, 135 degrees, 140 degrees, 145 degrees, 150 degrees, 155 degrees, or 160 degrees.

[0224] FIG. 38 further illustrates the top rail 4915 comprising a top rail angle 5245. The top rail angle 5245 is measured from rear wall 5123 to the top rail 4915. In many embodiments, the top rail angle 5245 can range from 35 degrees to 150 degrees or 70 degrees to 145 degrees. In some embodiments, top rail angle 5245 can be 35 degrees, 40 degrees, 45 degrees, 50 degrees, 55 degrees, 60 degrees, 65 degrees, 70 degrees, 75 degrees, 80 degrees, 85 degrees, 90 degrees, 95 degrees, 100 degrees, 105 degrees, 110 degrees, 115 degrees, 120 degrees, 125 degrees, 130 degrees, 135 degrees, 140 degrees, 145 degrees, or 150 degrees.

[0225] The rear wall 5123 of the upper region 4911 comprises a height 5180. The height 5180 of the rear wall 5123 is measured from the first reference point 5122 to the inflection point 5186, wherein the first reference point 5122 is positioned at the junction between the top rail 4915 and the rear wall 5123 parallel to the strikeface 4912. The height 5180 of the rear wall 5123 can range from 13.97 mm to 15.24 mm (0.55 inch to 0.60 inch), 15.24 mm to 17.78 mm (0.60 inch to 0.70 inch), 17.78 mm to 20.32 mm (0.70 inch to 0.80 inch), 20.32 mm to 21.59 mm (0.80 inch to 0.85 inch), 21.59 mm to 22.86 mm (0.85 inch to 0.90 inch), 22.86 mm to 24.13 mm (0.90 inch to 0.95 inch), 24.13 mm to 25.4 mm (0.95 inch to 1 inch), or 13.97 mm to 25.4 mm (0.55 inch to 1 inch). For example, the height 5180 of the rear wall 5123 can be 13.97 mm (0.55 inch), 14.73 mm (0.58 inch), 15.49 mm (0.61 inch), 16.26 mm (0.64 inch), 17.02 mm (0.67 inch), 17.78 mm (0.70 inch), 18.54 mm (0.73 inch), 19.3 mm (0.76 inch), 20.07 mm (0.79 inch), 20.83 mm (0.82 inch), 21.59 mm (0.85 inch), 22.35 mm (0.88 inch), 23.11 mm (0.91 inch), 23.88 mm (0.94 inch), 24.64 mm (0.97 inch), or 25.4 mm (1 inch). In some embodiments, the height 5180 of the rear wall 5123 ranges from 35% to 60%, 35% to 45%, 45% to 68%, 40% to 55%, 30% to 40%, 35% to 45%, 40% to 50%, 45% to 55%, or 50% to 60% of the total height of the golf club head 4900. For example, the height 5180 of the rear wall 5123 can be 35%, 38%, 41%, 44%, 47%, 50%, 53%, 56%, or 60% of the total height of the golf club head 4900.

[0226] The rear wall 5123 of the upper region 4911 can also comprise a secondary height 5180A. The secondary height 5180A is measured from the apex 5128 of the top rail 4915 to the inflection point 5186. The secondary height 5180A can range from 15.24 mm to 30.48 mm (0.60 inch to 1.2 inch). In some embodiments, the secondary height 5180A can range from 15.24 mm to 20.32 mm (0.60 inch to 0.80 inch), 20.32 mm to 25.4 mm (0.80 inch to 1.0 inch), or 25.4 mm to 30.48 mm (1.0 inch to 1.20 inches). For example, the secondary height 5180A can be 15.24 mm (0.60 inch), 15.49 mm (0.61 inch), 16.26 mm (0.64 inch), 17.02 mm (0.67 inch), 17.78 mm (0.70 inch), 18.54 mm (0.73 inch), 19.3 mm (0.76 inch), 20.07 mm (0.79 inch), 20.83 mm (0.82 inch), 21.59 mm (0.85 inch), 22.86 mm (0.90 inch), 24.13 mm (0.95 inch), 25.4 mm (1.0 inch), or 30.48 mm (1.2 inch). In some embodiments, the secondary height 5180A can range from 40% to 75% of the total height of the golf club head 4900. For example, the secondary height 5180A can be 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 60%, 65%, 70%, or 75% of the total height of the golf club head 4900.

[0227] The rear wall 5123 of the upper region 4911 further comprises a thickness 5156. The thickness 5156 is the perpendicular distance of the rear wall 5123 from the outer surface 4903 to the inner surface 5119. The thickness 5156 of the rear wall 5123 can range from 1.02 mm to 2.03 mm (0.040 inch to 0.080 inch). In some embodiments, the thickness 5156 of the rear wall 5123 can range from 1.02 mm to 1.52 mm (0.040 inch to 0.060 inch), or 1.52 mm to 2.03 mm (0.060 inch to 0.080 inch). For example, the thickness 5156 of the rear wall 5123 can be 1.02 mm (0.040 inch), 1.09 mm (0.043 inch), 1.17 mm (0.046 inch), 1.24 mm (0.049 inch), 1.30 mm (0.051 inch), 1.37 mm (0.054 inch), 1.45 mm (0.057 inch), 1.52 mm (0.060 inch), 1.60 mm (0.063 inch), 1.68 mm (0.066 inch), 1.75 mm (0.069 inch), 1.80 mm (0.071 inch), 1.88 mm (0.074 inch), 1.96 mm (0.077 inch), or 2.03 mm (0.080 inch). In many embodiments, the thickness 5156 of the rear wall 5123 is constant throughout. In other embodiments, the thickness 5156 of the rear wall 5123 can vary. In the exemplary embodiment, the thickness 5156 of the rear wall 5123 is a constant 1.14 mm (0.045 inch). The thickness of the rear wall allows energy from an impact to transfer to the inflection point to help induce a buckling effect.

[0228] The lower region 4913 of the body 4901 comprises a bottom incline 5125, a lower exterior wall 5127, a second reference point 5182, and a third reference point 5120. The bottom incline 5125 is below and adjacent the inflection point 5186. The lower exterior wall 5127 is below and adjacent the bottom incline 5125. The second reference point 5182 is disposed between or positioned at the junction between the bottom incline 5125 and the lower exterior wall 5127. The third reference point 5120 is disposed between the lower exterior wall 5127 and the sole 4906. The bottom incline 5125 is angled away from the top rail 4915 and away from the strikeface 4912 in a direction toward the second reference point 5182.

[0229] In some embodiments, bottom incline 5125 of the lower region 4913 comprises a bottom incline length 5129. Bottom incline length 5129 is measured from the inflection point 5186 to the second reference point 5182. The bottom incline length 5129 can range from 0 mm to 13.97 mm (0 inch to 0.55 inch). In some embodiments, the bottom incline length 5129 can range from 0 mm to 8.89 mm (0 inch to 0.35 inch), or 8.89 mm to 13.97 mm (0.35 inch to 0.55 inch). For example, the bottom incline length 5129 can be 0 mm (0 inch), 1.27 mm (0.05 inch), 2.54 mm (0.10 inch), 3.81 mm (0.15 inch), 5.08 mm (0.20 inch), 6.35 mm (0.25 inch), 7.62 mm (0.30 inch), 8.89 mm (0.35 inch), 10.16 mm (0.40 inch), 11.43 mm (0.45 inch), 12.7 mm (0.50 inch), or 13.97 mm (0.55 inch). In some embodiments, the bottom incline length 5129 can remain constant from the heel region 4902 to the toe region 4904. In other embodiments, the bottom incline length 5129 can vary from the heel region 4902 to the toe region 4904, as illustrated in FIG. 35. For example, the bottom incline length 5129 can increase from the heel region 4902 to the toe region 4904. In other embodiments, the bottom incline length 5129 can decrease from the heel region 4902 to the toe region 4904.

[0230] In some embodiments, the lower region 4913 further comprises a lower angle 5151 measured from between the bottom incline 5125 to the lower exterior wall 5127. In some embodiments, the lower angle 5151 can be less than 180 degrees. In a number of embodiments, the lower angle 5151 can be 130 degrees to 175 degrees. For example, the lower angle 5151 of the lower region 4913 can be 130 degrees, 135 degrees, 140 degrees, 145 degrees, 150 degrees, 155 degrees, 160 degrees, 165 degrees, 170 degrees, or 175 degrees.

[0231] The upper region 4911 and the lower region 4913 of the rear 4910 is separated by the inflection point 5186. Due to the height of the rear wall, the inflection point 5186 is positioned low on the body 4901. In many embodiments, the inflection point 5186 is positioned at least 40% down on the body 4901 below the apex 5128. For example, the inflection point 5186 can be positioned 40%, 42%, 44%, 46%, 48%, 50%, 52%, 54%, 56%, 58%, or 60% down on the body 4901 below the apex 5128. The low positioned inflection point 5186 allows for more leverage on the upper region 4911 to experience increased bending during impact with a ball, compared to a similar golf club head having a higher inflection point position.

[0232] The inflection point 5186 comprises an inflection angle 5196 measured from the rear wall 5123 of the upper region 4911, to the bottom incline 5125 of the lower region 4913. In some embodiments, the inflection angle 5196 can be measured from the rear wall 5123 to the lower exterior wall 5127 in the absence of the bottom incline 5125 (i.e., the bottom incline length is 0 cm (inch)). The inflection angle 5196 of the inflection point 5186 can range from at least 95 degrees to 150 degrees. In some embodiments, the inflection angle 5196 can be at least 95 degrees, 100 degrees, 105 degrees, 110 degrees, 115 degrees, 120 degrees, 125 degrees, 130 degrees, 135 degrees, 140 degrees, 145 degrees, or 150 degrees. In some embodiments, the inflection angle 5196 can be consistent from the heel region 4902 to the toe region 4904. In other embodiments, the inflection angle 5196 can vary from the heel region 4902 to the toe region 4904. In many embodiments, the inflection angle 5196 allows for the inflection point 5186 to act as a buckling point or plastic hinge upon the golf club head 4900 impacting the golf ball at strikeface 4912. In other examples of a similar golf club head having an inflection angle, wherein the inflection angle is less than 95 degrees (i.e., 90 degrees, or the bottom incline in oriented approximately perpendicular to the strikeface), the inflection angle would impede energy transfer and prevent bending at the inflection point.

[0233] The rear wall at the inflection point 5186 further comprises a thickness 5160. The thickness 5160 at the inflection point 5186 is measured perpendicularly of the inflection point 5186 from the exterior surface 4903 to the interior surface 5119. The thickness 5160 of the inflection point 5186 can range from 1.02 mm to 2.03 mm (0.040 inch to 0.080 inch). In some embodiments, the thickness 5160 of the inflection point 5186 can range from 1.02 mm to 1.52 mm (0.040 inch to 0.060 inch), or 1.52 mm to 2.03 mm (0.060 inch to 0.080 inch). For example, the thickness 5160 can be 1.02 mm (0.040 inch), 1.14 mm (0.045 inch), 1.27 mm (0.050 inch), 1.40 mm (0.055 inch), 1.52 mm (0.060 inch), 1.65 mm (0.065 inch), 1.78 mm (0.070 inch), 1.91 mm (0.075 inch), or 2.03 mm (0.080 inch). In many embodiments, the thickness 5160 of the inflection point 5186 is constant with the thickness 5156 of the rear wall 5123 and the thickness 5158 of the bottom incline 5125. In other embodiments, the thickness 5160 of the inflection point 5186 can be less than the thickness 5156 of the rear wall 5123 and the thickness 5158 of the bottom incline 5125. The thickness 5160 of the inflection point 5186 being consistent with or less than the thickness 5156, 5158 of the rear wall 5123 and the bottom incline 5125 allows for more uniform energy transfer and bending.

[0234] The body 4901 of the golf club head 4900 further comprises a minimum distance 5116, and a maximum distance 5118. The minimum distance 5116 of the body 4901 is measured as the perpendicular distance from the exterior surface 4903 of the strikeface 4912 in the upper region 4911 to the exterior surface 4903 of the rear wall 5123. The minimum distance 5116 can range from 5.08 mm (0.20 inch) to 11.18 mm (0.44 inch). In some embodiments, the minimum distance 5116 can range from 5.08 mm (0.20 inch) to 7.62 mm (0.30 inch), or 7.62 mm (0.30 inch) to 11.18 mm (0.44 inch). For example, the minimum distance 5116 can be 5.08 mm (0.20 inch), 5.59 mm (0.22 inch), 6.10 mm (0.24 inch), 6.60 mm (0.26 inch), 7.11 mm (0.28 inch), 7.62 mm (0.30 inch), 8.13 mm (0.32 inch), 8.64 mm (0.34 inch), 9.14 mm (0.36 inch), 9.65 mm (0.38 inch), 10.16 mm (0.40 inch), 10.67 mm (0.42 inch), or 11.18 mm (0.44 inch). The maximum distance 5118 of the body 4901 is measured as the perpendicular distance from the exterior surface 4903 of the strikeface 4912 in the lower region 4913 to the exterior surface 4903 of the third reference point 5120. The maximum distance 5118 can range from 15.24 mm (0.60 inch) to 25.4 mm (1.0 inch). In some embodiments, the maximum distance 5118 can range from 15.24 mm (0.60 inch) to 20.32 mm (0.80 inch), or 20.32 mm (0.80 inch) to 25.4 mm (1.0 inch). For example, the maximum distance 5118 can be 15.24 mm (0.60 inch), 16.26 mm (0.64 inch), 17.27 mm (0.68 inch), 18.29 mm (0.72 inch), 19.30 mm (0.76 inch), 20.32 mm (0.80 inch), 21.34 mm (0.84 inch), 22.35 mm (0.88 inch), 22.86 mm (0.90 inch), 23.37 mm (0.92 inch), 23.88 mm (0.94 inch), 24.38 mm (0.96 inch), or 25.4 mm (1.0 inch).

[0235] The body 4901 of the golf club head 4900 further comprises an internal cavity distance 5114 as illustrated in FIG. 39. The internal cavity distance 5114 is measured as the perpendicular distance from the exterior surface 4903 of the strikeface 4912 in the lower region 4913 to the interior surface 5119 of the rear wall 5123. The internal cavity distance 5114 can range from 10.16 mm to 20.32 mm (0.40 inch to 0.80 inch). In some embodiments, the internal cavity distance 5114 can range from 10.16 mm to 15.24 mm (0.40 inch to 0.60 inch), or 15.24 mm to 20.32 mm (0.60 inch to 0.80 inch). For example, the internal cavity distance 5114 can be 10.16 mm (0.40 inch), 11.18 mm (0.44 inch), 12.19 mm (0.48 inch), 13.21 mm (0.52 inch), 14.22 mm (0.56 inch), 15.24 mm (0.60 inch), 16.26 mm (0.64 inch), 17.27 mm (0.68 inch), 18.29 mm (0.72 inch), 19.30 mm (0.76 inch), or 20.32 mm (0.80 inch).

[0236] As illustrated in FIG. 35-38, the golf club head 4900 can be a hollow, or at least partially hollow body comprising an internal cavity 4916. Internal cavity 4916 of the body 4901 comprises a volume. The volume of the internal cavity 4916 can range from 19.66 cm³ (1.20 in³) to 32.77 cm³ (2.0 in³). In some embodiments, the internal cavity 4916 can range from 19.66 cm³ (1.20 in³) to 26.22 cm³ (1.6 in³), or 26.22 cm³ (1.6 in³) to 32.77 cm³ (2.0 in³). For example, the internal cavity 4916 can comprise a volume of 19.66 cm³ (1.20 in³), 21.30 cm³ (1.30 in³), 22.94 cm³ (1.40 in³), 24.58 cm³ (1.50 in³), 26.22 cm³ (1.60 in³), 27.86 cm³ (1.70 in³), 29.50 cm³ (1.80 in³), 31.14 cm³ (1.90 in³), or 32.77 cm³ (2.0 in³). Similarly, the solid portion of the body 4900, void of the cavity 4916, further comprises a material volume. The material volume of the body can range from 49.16 cm³ (3.0 in³) to 65.55 cm³ (4.0 in³). In some embodiments, the material volume of the body can range from 49.16 cm³ (3.0 in³) to 57.35 cm³ (3.5 in³), or 57.35 cm³ (3.5 in³) to 65.55 cm³ (4.0 in³). For example, the material volume of the body can be 49.16 cm³ (3.0 in³), 50.80 cm³ (3.10 in³), 52.44 cm³ (3.20 in³), 54.08 cm³ (3.30 in³), 55.72 cm³ (3.40 in³), 57.35 cm³ (3.50 in³), 58.99 cm³ (3.60 in³), 60.63 cm³ (3.70 in³), 62.27 cm³ (3.80 in³), 63.91 cm³ (3.90 in³), or 65.55 cm³ (4.0 in³).

[0237] In many embodiments, the internal cavity 4916 of the body 4900 can be void of any substance. In other embodiments, the internal cavity 4916 of the body 4900 can comprise a polymer (not pictured), wherein the polymer can at least partially fill the internal cavity 4916. The polymer can be polyethylene terephthalate, high-density polyethylene, polyvinyl chloride, polycarbonate, polypropylene, other thermoplastics, composites polymers or any combination thereof. The polymer can fill 10% to 80%, 10% to 25%, 15% to 30%, 30% to 45%, 45% to 60%, 60% to 75%, 75% to 80%, 10% to 40%, 30% to 60%, or 40% to 80% of the internal cavity of the body. For example, the polymer can fill 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, or 85% of the internal cavity of the body. In some embodiments, the polymer fills 80% of the internal cavity 4916 of the body 4901.

[0238] The polymer to at least partially fill the internal cavity 4916 of the body 4901 comprises a specific gravity ranging from 0.05 to 4. In some embodiments, the specific gravity ranges from 0.05 to 0.10, 0.10 to 0.50, 0.50 to 1.0, 1.0 to 2.0, or 2.0 to 4.0. For example, the specific gravity of the polymer can be 0.50, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, or 4.0. In some embodiments, the specific gravity of the polymer is proportional to the mass of the polymer, wherein 1 specific gravity of the polymer is equal to 1 gram. Similarly, in those exemplary embodiments, the volume is proportional to the polymer specific gravity, wherein 1 specific gravity of the polymer is equal to 1 cc. In other embodiments, the volume is not proportional to the specific gravity of the polymer. For example, the ratio of the polymer specific gravity to the polymer volume can be 2:1 cc, 2:3 cc, 2:4 cc, 3:1 cc, 3:2 cc, 3:4 cc, 4:1 cc, 4:2 cc, or 4:3 cc.

[0239] In some embodiments, as illustrated in FIG. 40, the golf club head 4900 can further comprise a first aperture 5134 located on the toe region 4904 and a second aperture 5136 located in a hosel of the golf club head 4900. The first aperture 5134 is configured to receive a toe weight (not pictured), wherein the toe weight can range from 2 grams to 7 grams. In some embodiments, the toe weight can range from 2 grams to 5 grams, or 5 grams to 7 grams. For example, the toe weight can be 2 grams, 3 grams, 4 grams, 5 grams, 6 grams, or 7 grams. The second aperture 5136 is configured to receive a tip weight (not pictured), wherein the tip weight can range from 2 grams to 7 grams. In some embodiments, the tip weight can range from 2 grams to 5 grams, or 5 grams to 7 grams. For example, the tip weight can be 2 grams, 3 grams, 4 grams, 5 grams, 6 grams, or 7 grams. In many embodiments, the first aperture 5134 and the second aperture 5136 can further be configured to receive the polymer. The first aperture 5134 can receive 1 gram to 9 grams of polymer (e.g., 1 gram, 2 grams, 3 grams, 4 grams, 5 grams, 6 grams, 7 grams, 8 grams, or 9 grams). Similarly, the second aperture 5136 can receive 1 gram to 9 grams of polymer (e.g., 1 gram, 2 grams, 3 grams, 4 grams, 5 grams, 6 grams, 7 grams, 8 grams, or 9 grams). The toe and tip weight, and the polymer housed within the first aperture 5134 and the second aperture 5136 can affect the swing weight to optimize CG and MOI.

[0240] The internal cavity 4916 of the body 4901 further comprises interior surface 5119. In some embodiments, the interior surface 5119 of the rear 4910 is a planar and smooth surface. In other embodiments as illustrated in FIG. 38, the interior surface 5119 of the internal cavity 4916 of the rear 4910 comprises a plurality of ribs 4952. The plurality of ribs 4952 extend in a direction from top rail 4915 toward the sole 4906. The plurality of ribs 4952 can be located anywhere on interior surface 5119 of the rear 4910. In some examples, the plurality of ribs 4952 can be positioned onto a portion of interior surface 5119 of the lower exterior wall 5127. In other examples, the plurality of ribs 4952 can be positioned on a portion of the interior surface 5119 of the rear wall 5123. In some embodiments, the plurality of ribs 4952 can be positioned on a portion of the interior surface 5119 of the rear 4910 and can extend into another portion of the rear 4910. For example, the plurality of ribs 4952 are positioned on a portion of the interior surface 5119 of the rear wall 5123 and can extend up to at least a portion of the bottom incline 5125, or at least a portion of the lower exterior wall 5127. The plurality of ribs 4952 can comprise between one to eight ribs. For example, the plurality of ribs 4952 can comprise one rib, two ribs, three ribs, four ribs, five ribs, six ribs, seven ribs, or eight ribs. In embodiments having one or more plurality of ribs 4952, the plurality of ribs 4952 can be spaced equidistance from each other or more concentrated near the heel region 4902, toe region 4904, top rail 4915, or sole 4906. The plurality of ribs 4952 and the location of the plurality of ribs 4952 can help optimize the frequency and amplitude of sound response.

[0241] In some embodiments, body 4901 can comprise stainless steel, titanium, aluminum, a steel alloy (e.g. 455 steel, 475 steel, 431 steel, 17-4 stainless steel, maraging steel), a titanium alloy (e.g. Ti 7-4, Ti 6-4, T-9S, Ti SSAT2041, Ti SP700, Ti 15-0-3, Ti 15-5-3, Ti 3-8-6-4-4, Ti 10-2-3, Ti 15-3-3-3, Ti-6-6-2, Ti-185, or any combination thereof), an aluminum alloy, or a composite material. In other embodiments, body 4901 can comprise carpenter grade 455 steel, carpenter grade 475 steel, C300 steel, C350 steel, a Ni-Co-Cr steel alloy, a quench and tempered steel alloy, or 565 steel. In some embodiments, strikeface 4912 can comprise stainless steel, titanium, aluminum, a steel alloy (e.g. 455 steel, 475 steel, 431 steel, 17-4 stainless steel, maraging steel), a titanium alloy (e.g. Ti 7-4, Ti 6-4, T-9S, Ti SSAT2041, Ti SP700, Ti 15-0-3, Ti 15-5-3, Ti 3-8-6-4-4, Ti 10-2-3, Ti 15-3-3-3, Ti-6-6-2, Ti-185, or any combination thereof), an aluminum alloy, or a composite material. In other embodiments, strikeface 4912 can comprise carpenter grade 455 steel, carpenter grade 475 steel, C300 steel, C350 steel, a Ni-Co-Cr steel alloy, a quench and tempered steel alloy, or 565 steel. In some embodiments, the body 4901 can comprise the same material as the strikeface 4912. In some embodiments, the body 4901 can comprise a different material than the strikeface 4912.

[0242] FIG. 42 illustrates a back perspective view of an embodiment of golf club head 5600 and FIG. 43 illustrates a back heel-side perspective view of golf club head 5600 according to the embodiment of FIG. 42. In some embodiments, golf club head 5600 can be similar to golf club head 1000 (FIG. 1), golf club head 2200 (FIG. 8), golf club head 2700 (FIG. 13), golf club head 3200 (FIG. 18), golf club head 3700 (FIG. 23), and/or golf club head 4400 (FIG. 30). Golf club head 5600 can be an iron-type golf club head.

[0243] Golf club head 5600 comprises a body 5601. In some embodiments, body 5601 can be similar to body 1001 (FIG. 1), body 2201 (FIG. 8), body 2701 (FIG. 13), body 3201 (FIG. 18), body 3701 (FIG. 23), and/or body 4401 (FIG. 30). The body 5601 comprises an exterior surface 5603, a strikeface 5612, a heel region 5602, a toe region 5604 opposite the heel region 5602, a sole 5606, a top rail 5615, and a rear 5610. The strikeface 5612, sole 5606, top rail 5615, and rear 5610 of the body 5601 together form an internal cavity 5616. Furthermore, the golf club head 5600 can be divided into an upper region 5611 and a lower region 5613 (see FIG. 44).

[0244] The rear 5610 of the golf club head 5600 can comprise an indention 5630 that alters the deflection and/or weighting of the club head. The rear 5610 of the golf club head can further comprise a ledge 5825 or step wall below the indention 5630. The rear 5610 further comprises an upper perimeter portion 5609, which extends along the top rail 5615 and wraps down the sides of the toe region 5604 and heel region 5602. A toe slit 5666 and a heel slit 5662 are each positioned between a part of the upper perimeter portion 5609 and a lower exterior wall 5727 of a lower region 5613 of the club head 5600, allowing structural bending between upper and lower halves of the club head 5600. This bending allowed by the toe slit 5666 and heel slit 5662 results in greater deflection of the strikeface 5612 over a club head without these slits. The club head 5600 can further comprise a vibration damping layer 5878 on an interior surface 5819 of the strikeface 5612. In some embodiments, the internal cavity 5616 can be filled or partially filled with a polymer material.

[0245] Body 5601 of FIGS. 42-48 comprises a blade length. The blade length for body 5601 can be measured similar to blade length 3725 as shown and described in FIG. 29 (i.e., a measurement parallel to the flat surface of the strikeface 3712, from a toe edge 3726 of the strikeface 3712, to strikeface end 3727 before the strikeface 3712 integrally curves into the hosel). The blade length of the body 5601 can range from 6.35 cm (2.50 inches) to 7.37 cm (2.90 inches). For example, in some embodiments, the body 3701 can comprise a blade length of 6.35 cm (2.50 inches), 6.45 cm (2.54 inches), 6.55 cm (2.58 inches), 6.65 cm (2.62 inches), 6.76 cm (2.66 inches), 6.86 cm (2.70 inches), 6.96 cm (2.74 inches), 7.06 cm (2.78 inches), 7.16 cm (2.82 inches), 7.26 cm (2.86 inches), or 7.37 cm (2.90 inches).

[0246] The sole can comprise a cascading sole portion of the sole, as described in greater detail below. As shown in FIG. 46, a deflection feature of the golf club head 5600 can be a uniform thinned region 6060, located at the sole 5606 and stretching between the rear 5610 of the body 5601 and the strikeface 5612, toward the cascading sole portion of the sole. In the illustrated embodiment, the uniform thinned region 6060 comprises a sole thickness measured perpendicular from the exterior surface 5603 to an interior surface 5819 at the uniform thinned region 6060, which can remain constant from the bottom of the strikeface 5612 to adjacent the cascading sole portion of the sole. In some embodiments, the sole thickness of the uniform thinned region 6060 can be thinner than a conventional sole. For example, in some embodiments, the sole thickness of the uniform thinned region 6060 may range from approximately 1.016 mm (0.040 inch) to 2.032 mm (0.080 inch). In other embodiments, the sole thickness of the uniform thinned region 6060 may be within the range of 1.016 mm (0.040 inch) to 1.27 mm (0.050 inch), 1.27 mm (0.050 inch) to 1.524 mm (0.060 inch), 1.524 mm (0.060 inch) to 1.778 mm (0.070 inch), 1.778 mm (0.070 inch) to 2.032 mm (0.080 inch), 1.016 mm (0.040 inch) to 1.397 mm (0.055 inch), 1.143 mm (0.045 inch) to 1.524 mm (0.060 inch), 1.27 mm (0.050 inch) to 1.651 mm (0.065 inch), 1.397 mm (0.055 inch) to 1.778 mm (0.070 inch), 1.524 mm (0.060 inch) to 1.905 mm (0.075 inch), or 1.651 mm (0.065 inch) to 2.032 mm (0.080 inch). For example, the sole thickness of the uniformed thinned region 4860 can be 1.016 mm (0.040 inch), 1.143 mm (0.045 inch), 1.27 mm (0.050 inch), 1.524 mm (0.060 inch), 1.651 mm (0.065 inch), 1.778 mm (0.070 inch), 1.905 mm (0.075 inch), or 2.032 mm (0.080 inch).

[0247] FIG. 44 illustrates a cross-section of golf club head 5600 along the cross-sectional line LVIII-LVIII in FIG. 42, according to one embodiment. As seen in FIG. 44, strikeface 5612 comprises a high region 5876, a middle region 5874, and a low region 5872.

[0248] The strikeface 5612 of the body 5601 further comprises a thickness 5854 measured perpendicularly to the strikeface 5612 from the exterior surface 5603 to an interior surface 5819. The thickness 5854 of the strikeface 5612 can range from 1.016 mm to 2.54 mm (0.040 inch to 0.100 inch). For example, the thickness 5854 of the strikeface 4412 can be 1.016 mm (0.040 inch), 1.143 mm (0.045 inch), 1.27 mm (0.050 inch), 1.397 mm (0.055 inch), 1.524 mm (0.060 inch), 1.651 mm (0.065 inch), 1.778 mm (0.070 inch), 1.905 mm (0.075 inch), 2.032 mm (0.080 inch), 2.159 mm (0.085 inch), 2.286 mm (0.090 inch), 2.413 mm (0.095 inch), or 2.54 mm (0.100 inch). In some embodiments, the thickness 5854 of the strikeface 5612 can vary from the heel region 5602 to the toe region 5604, and/or from the top rail 5615 to the sole 5606. For example, the thickness 5854 of the strikeface 5612 can be greatest at the central portion near the middle region 5874 of the strikeface 5612 and taper along the periphery near the high region 5876 and the low region 5872 of strikeface 5612. In many embodiments, the center of the strikeface 5612 can have a thickness 5854 of 2.286 mm (0.090 inch) and the periphery of the strikeface 5612 can have a thickness 5854 of 1.778 mm (0.070 inch). In other examples, the thickness 5854 can increase, decrease, or any variation thereof starting at the central region near the middle region 5874 of the strikeface 5612 and extending toward the periphery near the high region 5876 and the low region 5872.

[0249] The upper region 5611 of rear 5610 comprises the upper perimeter portion 5609, the indention 5630, and the ledge 5825. The upper perimeter portion comprises the top rail of the club head and wraps down around a length of the toe and heel regions of the club head. The upper perimeter portion 5609 extends along a top edge of the golf club head 5600 from the heel region 5602 to the toe region 5604. In the toe region 5604 the upper perimeter portion 5609 extends down along a perimeter of the toe region 5604. In some embodiments, the upper perimeter portion 5609 extends roughly halfway down along the perimeter of the toe region 5604. The upper perimeter portion abuts the indention. The upper perimeter portion 5609 of the rear 5610 can provide perimeter weighting for the club head 5600. In addition, the upper perimeter portion 5609 allows stresses in the top rail 5615 to be dissipated into the rear 5610 of the club head 5600.

[0250] The indention 5630 is located on the exterior surface 5603, below the upper perimeter portion and above the lower region 5613 of the club head 5600. The indention 5630 of the rear 5610 extends inwards towards the strikeface of the golf club head 5600. The indention 5630 is located in the upper portion 5611 of the club head 5600. In some embodiments, the indention 5630 is located primarily in an upper half of the golf club head 5600. The indention 5630 is bounded on its top, toe, and heel sides by the upper perimeter portion 5609. The indention 5630 is bounded on its bottom side by the ledge 5825.

[0251] The ledge 5825 extends in a direction generally from the heel region 5602 towards the toe region 5604. The ledge 5825 helps form a lower boundary of the indention 5630. The ledge 5825 can be located at various heights above the ground plane 10 when the club head 5600 is at address position. The ledge 5825 can comprise multiple segments, wherein each segment is located at a different height above the ground plane 10, as shown in the rear view of FIG. 42. For example, the ledge 5825 can comprise a segment located in the toe region 5604 that is higher from the ground plane 10 than a segment located, at least partially, in the heel region 5602.

[0252] The ledge 5825 of the rear 5610 of the club head 5600 can be positioned in a plane roughly perpendicular to the strikeface 5612 plane. The ledge 5825 runs the length of the club head 5600 from the heel region 5602 to the toe region 5604. The ledge 5825 can also be thought of as a ledge or groove. At the heel end the ledge 5825 can blend into the heel slit 5662. At the toe end, the ledge 5825 can blend into the toe slit 5666.

[0253] The ledge 5825 can be angled with respect to the ground plane 10 at a ledge angle (not illustrated). In some embodiments, the ledge angle, measured from the ledge 5825 to ground plane 10, can range from 15 degrees to 45 degrees. In some embodiments, the ledge angle can be 15 degrees, 16 degrees, 17 degrees, 18 degrees, 19 degrees, 20 degrees, 21 degrees, 22 degrees, 23 degrees, 24 degrees, 25 degrees, 26 degrees, 27 degrees, 28 degrees, 29 degrees, 30 degrees, 31 degrees, 32 degrees, 33 degrees, 34 degrees, 35 degrees, 36 degrees, 37 degrees, 38 degrees, 39 degrees, 40 degrees, 41 degrees, 42 degrees, 43 degrees, 44 degrees, or 45 degrees.

[0254] The toe and heel slits 5666, 5662 are positioned on the rear 5610 of the club head 5600 roughly halfway upward from the ground plane 10 towards the top rail 5615. The toe and heel slits 5666, 5662 span short lengths across the toe and heel regions 5604, 5604 of the club head 5600, respectively. The toe and heel slits 5666, 5662 extend from either end of the ledge 5825. The toe slit 5666 is positioned in the toe region 5604 between the upper perimeter portion 5609 and the lower region 5613 of the club head 5600. The heel slit 5662 is positioned in the heel region 5602 between the upper perimeter portion 5609 next to and adjacent the hosel.

[0255] The toe slit 5666 and the heel slit 5662 are oriented in a toe-to-heel direction. The toe slit 5666 can be positioned between approximately halfway and approximately 2/3 of the way upwards from the ground plane 10 towards the top rail 5615, measured parallel to the strikeface 5612. The heel slit 5662 can also be positioned between approximately halfway up and approximately 2/3 of the way upwards from the ground plane 10 towards the top rail 5615. In some embodiments, the heel slit 5662 is positioned lower with respect to the ground plane 10 than the toe slit 5666. In these embodiments, the upper perimeter portion 5609 extends lower in the heel region 5602 than in the toe region 5604.

[0256] The toe slit 5666 has a depth 6267 such that a deepest surface of the slit 5666 blends into the indention 5630. The toe slit depth 6267 can be measured from the outer surface of the upper perimeter portion to a lowest point inside the toe slit. The toe slit depth 6267 can range between 1.27 mm (0.05 inch) and 5.08 mm (0.20 inch). For example, the toe slit depth 6267 can range between 1.27 mm (0.05 inch) and 3.81 mm (0.15 inch), or 3.81 mm (0.15 inch) and 5.08 mm (0.20 inch). A toe slit height 5668 can be measured in a direction generally orthogonal to the ground plane from the intersection of the upper perimeter portion 5609 and the toe slit 5666 to the intersection of the ledge 5825 and the toe slit 5666. The toe slit height 5668 can range between 2.54 mm (0.10 inch) and 7.62 mm (0.30 inch). For example, the toe slit height 5668 can range between 3.81 mm (0.15 inch) and 4.32 mm (0.17 inch), 2.54 mm (0.10 inch) and 3.81 mm (0.15 inch), 3.81 mm (0.15 inch) and 5.08 mm (0.20 inch), or 5.08 mm (0.20 inch) and 7.62 mm (0.30 inch). The toe slit 5666 can comprise a length 5669 between the outer edge of the toe region 5604 to the indention 5630 where the toe slit 5666 terminates, as shown in FIG. 42. The toe slit length 5669 can range between 8.08 mm (0.318 inch) and 10.62 mm (0.418 inch). For example, the toe slit length 5669 can be 8.08 mm (0.318 inch), 8.13 mm (0.320 inch), 8.38 mm (0.330 inch), 8.64 mm (0.340 inch), 8.89 mm (0.350 inch), 9.14 mm (0.360 inch), 9.34 mm (0.368 inch), 9.40 mm (0.370 inch), 9.65 mm (0.380 inch), 9.91 mm (0.390 inch), 10.16 mm (0.400 inch), 10.41 mm (0.410 inch), or 10.62 mm (0.418 inch). The dimensions of the toe slit 5666 can affect the deflection of the strikeface 5612, as described below.

[0257] The heel slit 5662 is similar in depth and orientation to the toe slit 5666. However, in some embodiments, the angular orientation of the heel slit 5662 with respect to the ground plane differs slightly from the angular orientation of the toe slit 5666. In some embodiments, the heel slit 5662 does not extend to a heel-most point of the club head 5600. A heel slit height 5664 can be measured in a direction generally orthogonal to the ground plane from the intersection of the upper perimeter portion 5609 and the heel slit 5662 to the intersection of the ledge 5825 and the heel slit 5662. The heel slit height 5664 can range between 2.54 mm and 7.62 mm (0.10 inch and 0.30 inch). For example, the heel slit height 5664 can range between 3.30 mm and 4.06 mm (0.13 inch and 0.16 inch), 2.54 mm and 3.81 mm (0.10 inch and 0.15 inch), 3.81 mm and 5.08 mm (0.15 inch and 0.20 inch), or 5.08 mm and 7.62 mm (0.20 inch and 0.30 inch). The heel slit can comprise a length 5665, measured from adjacent an edge of the perimeter portion towards the heel region, as shown in FIG. 42. The heel slit length 5665 can be longer than the toe slit length 5669. In other embodiments, the heel and toe slits are the same length. The heel slit length 5665 can range between 8.26 mm and 10.80 mm (0.325 inch and 0.425 inch). For example, the heel slit length 5665 can be 8.26 mm (0.325 inch), 8.38 mm (0.330 inch), 8.51 mm (0.335 inch), 8.64 mm (0.340 inch), 8.76 mm (0.345 inch), 8.89 mm (0.350 inch), 9.02 mm (0.355 inch), 9.14 mm (0.360 inch), 9.27 mm (0.365 inch), 9.40 mm (0.370 inch), 9.53 mm (0.375 inch), 9.65 mm (0.380 inch), 9.78 mm (0.385 inch), 9.91 mm (0.390 inch), 10.03 mm (0.395 inch), 10.16 mm (0.400 inch), 10.29 mm (0.405 inch), 10.41 mm (0.410 inch), 10.54 mm (0.415 inch), 10.67 mm (0.420 inch), or 10.80 mm (0.425 inch). The dimensions of the heel slit 5662 can affect the deflection of the strikeface 5612, as described below.

[0258] In the lower region 5613 of the club head 5600, the body 5601 extends a greater perpendicular distance from the strikeface 5612 than the upper perimeter portion 5609 or the indention 5630. The lower region 5613 comprises, in part, a solid region adjacent the sole 5606 and the rear 5610 of the club head 5600. The solid region provides perimeter weighting to the club head 5600. The solid region is bounded by the sole 5606 and a lower exterior wall 5727. A front edge of the solid region defines a part of the internal wall of the internal cavity 5616.

[0259] The cross-section of golf club head 5600 in FIG. 44 further illustrates the rear 5610. The rear 5610 can be divided and understood with respect to the upper region 5611 and the lower region 5613 of the club head 5600. The upper region 6511 of the rear comprises the upper perimeter portion 5609 and the indention 5630, including the ledge 5825. As illustrated in FIG. 44, the upper perimeter portion 5609 comprises the top rail 5615, a rear wall 5723, and a top wall 5719. The indention 5630 is formed by the top wall 5719 of the upper perimeter portion, an indention wall 5821, and a ledge 5825.

[0260] As seen in FIG. 44, from a cross-sectional view, the upper region 5611 of rear 5610 comprises the top rail 5615, the rear wall 5723, the top wall 5719, the indention wall 5821, and the ledge 5825. The rear wall 5723 of rear 5610 is located below and adjacent to the top rail 5615. The top wall 5719 of rear 5610 is located below and adjacent to the rear wall 5723. The indention wall 5821 is located below and adjacent to the top wall 5719. The ledge 5825 is located below and adjacent to the indention wall 5821. In short, the top wall 5719 and the ledge 5825 are angled towards the strikeface and connect to the indention wall 5821, to form the indention 5630. The upper region 5611 further comprises a first reference point 5722 located between top rail 5615 and rear wall 5723, a second reference point 5782 located between rear wall 5723 and top wall 5719, a first inflection point 5786 located between top wall 5719 and the indention wall 5821, a second inflection point 5792 located between the indention wall 5821 and the ledge 5825, and a third inflection point 5794 located between the ledge 5825 and the lower region 5613.

[0261] In some embodiments, top rail 5615 of the upper perimeter portion can be a flatter and taller top rail or skirt than in irons known to one skilled in the art. The flatter and taller rail can compensate for mishits of strikeface 5612 to increase playability off the tee. In some embodiments, the length of top rail 5615, measured from heel region 5602 to toe region 5604, can be 70% to 95% of the length of golf club head 5600. In many embodiments, indention 5630 comprises a top rail box spring design. For some fairway iron-type golf club head embodiments, indention 5630 can be a reverse scoop or indentation of rear 5610 with body 5601 comprising a greater thickness toward sole 5606. In many embodiments, the top rail of the upper perimeter portion and the indention 5630 provide an increase in the overall bending of strikeface 5612. In some embodiments, the bending of strikeface 5612 can allow for a 2% to 5% increase of energy. The indention 5630 allows for strikeface 5612 to be thinner and allow additional overall bending.

[0262] . The top rail 5615 of the upper perimeter portion comprises a thickness 6052. The thickness 6052 of the top rail 5615 can range from 1.016 mm (0.040 inch) to 2.032 mm (0.080 inch). For example, the thickness 6052 of the top rail 5615 can be 1.016 mm (0.040 inch), 1.092 mm (0.043 inch), 1.168 mm (0.046 inch), 1.244 mm (0.049 inch), 1.295 mm (0.051 inch), 1.372 mm (0.054 inch), 1.448 mm (0.057 inch), 1.524 mm (0.060 inch), 1.600 mm (0.063 inch), 1.676 mm (0.066 inch), 1.753 mm (0.069 inch), 1.803 mm (0.071 inch), 1.880 mm (0.074 inch), 1.956 mm (0.077 inch), or 2.032 mm (0.080 inch). In many embodiments, the thickness 6052 of the top rail 5615 is constant throughout. In other embodiments, the thickness 6052 of the top rail 5615 can vary. In the exemplary embodiment, the thickness 6052 of the top rail 5615 decreases from the strikeface 5612 toward the rear wall 5823. In many embodiments due to the thickness 6052 of the top rail, top rail 5615 can provide an increase in the overall bending of strikeface 5612.

[0263] FIG. 45 illustrates a view of top rail 5615 and a portion of rear 5610 of the cross-section of golf club head 5600 of FIG. 42, along a cross-sectional line LVIII-LVIII in FIG. 42 that is similar to the cross-section of FIG. 44. In many embodiments, golf club head 5600 comprises a rear angle 5940, a top rail angle 5945, and a strikeface angle 5950. Rear angle 5940 is measured from top wall 5819 to rear wall 5823 of upper region 5611. In many embodiments, rear angle 5940 can range from 70 degrees to 140 degrees. In some embodiments, rear angle 5940 can be 70 degrees, 75 degrees, 80 degrees, 85 degrees, 90 degrees, 100 degrees, 105 degrees, 110 degrees, 115 degrees, 120 degrees, 125 degrees, 130 degrees, 135 degrees, or 140 degrees. In some embodiments, the rear angle 5940 is approximately 122 degrees.

[0264] The strikeface 5612 further comprises a strikeface angle 5950. Strikeface angle 5950 is measured from the strikeface 5612 to the top rail 5615, wherein the strikeface angle 5950 can range from 70 degrees to 160 degrees or 70 degrees to 110 degrees. In some embodiments, strikeface angle 5950 can be 70 degrees, 75 degrees, 80 degrees, 90 degrees, 95 degrees, 100 degrees, 105 degrees, 110 degrees, 115 degrees, 120 degrees, 125 degrees, 130 degrees, 135 degrees, 140 degrees, 145 degrees, 150 degrees, 155 degrees, or 160 degrees. In some embodiments, the strikeface angle 5950 is approximately 90 degrees.

[0265] FIG. 45 further illustrates the top rail 5615 comprising a top rail angle 5945. The top rail angle 5945 is measured from rear wall 5823 to the top rail 5615. In many embodiments, the top rail angle 5945 can range from 70 degrees to 160 degrees or 90 degrees to 110 degrees. In some embodiments, top rail angle 5945 can be 70 degrees, 75 degrees, 80 degrees, 85 degrees, 90 degrees, 95 degrees, 100 degrees, 105 degrees, 110 degrees, 115 degrees, 120 degrees, 125 degrees, 130 degrees, 135 degrees, 140 degrees, 145 degrees, 150 degrees, 155 degrees, or 160 degrees. In some embodiments, the top rail angle 5945 is approximately 131 degrees.

[0266] The rear wall 5723 extends from the first reference point 5722 to the second reference point in an orientation roughly parallel to the strikeface. The rear wall 5723 connects the top rail and the top wall 5719. The rear wall 5823 of the upper region 5611 comprises a height 5880. The height 5880 of the rear wall 5823 is measured from the first reference point 5722 to the second reference point 5782. The height 5880 of the rear wall 5823 can range from 1.397 mm to 1.524 mm (0.055 inch to 0.060 inch), 1.524 mm to 1.778 mm (0.060 inch to 0.070 inch), 1.778 mm to 2.032 mm (0.070 inch to 0.080 inch), 2.032 mm to 2.159 mm (0.080 inch to 0.085 inch), or 13.97 mm to 21.59 mm (0.55 inch to 0.85 inch). For example, the height 4680 of the rear wall 4623 can be 13.97 mm (0.55 inch), 14.73 mm (0.58 inch), 15.49 mm (0.61 inch), 16.26 mm (0.64 inch), 17.02 mm (0.67 inch), 17.78 mm (0.70 inch), 18.54 mm (0.73 inch), 19.30 mm (0.76 inch), 20.07 mm (0.79 inch), 20.83 mm (0.82 inch), or 21.59 mm (0.85 inch). In some embodiments, the height 5880 of the rear wall 4623 can range from 35% to 60%, 35% to 45%, 45% to 68%, 40% to 55%, 30% to 40%, 35% to 45%, 40% to 50%, 45% to 55%, or 50% to 60% of the total height of the golf club head 5600. For example, the height 5880 of the rear wall 5823 can be 35%, 38%, 41%, 44%, 47%, 50%, 53%, 56%, or 60% of the total height of the golf club head 5600.

[0267] The rear wall 5823 of the upper region 5611 can also comprise a height 5680A. The height 5680A is measured from the apex 5828 of the top rail 5615 to the second reference point 5782. The height 5880A can range from 15.24 mm to 25.4 mm (0.60 inch to 1.0 inch). For example, the height 5880A can be 15.24 mm (0.60 inch), 15.49 mm (0.61 inch), 16.26 mm (0.64 inch), 17.02 mm (0.67 inch), 17.78 mm (0.70 inch), 18.54 mm (0.73 inch), 19.30 mm (0.76 inch), 20.07 mm (0.79 inch), 20.83 mm (0.82 inch), 21.59 mm (0.85 inch), 22.86 mm (0.90 inch), 24.13 mm (0.95 inch), or 25.4 mm (1.0 inch). In some embodiments, the height 5880A can range from 40% to 75% of the total height of the golf club head 5600. For example, the height 5880A can be 40%, 44%, 47%, 50%, 53%, 56%, 60%, 65%, 70%, or 75% of the total height of the golf club head 5600.

[0268] The rear wall 5823 of the upper region 5611 further comprises a rear wall thickness 5856. The rear wall thickness 5856 is the perpendicular distance of the rear wall 5823 from the outer surface 5603 to the inner surface 5619 of the internal cavity 5630. The rear wall thickness 5856 can range from 1.016 mm to 2.032 mm (0.040 inch to 0.080 inch). For example, the rear wall thickness 5856 can be 1.016 mm (0.040 inch), 1.092 mm (0.043 inch), 1.168 mm (0.046 inch), 1.244 mm (0.049 inch), 1.295 mm (0.051 inch), 1.372 mm (0.054 inch), 1.448 mm (0.057 inch), 1.524 mm (0.060 inch), 1.600 mm (0.063 inch), 1.676 mm (0.066 inch), 1.753 mm (0.069 inch), 1.803 mm (0.071 inch), 1.880 mm (0.074 inch), 1.956 mm (0.077 inch), or 2.032 mm (0.080 inch). In many embodiments, the rear wall thickness 5856 is constant throughout. In other embodiments, the rear wall thickness 5856 can vary. In the exemplary embodiment, the rear wall thickness 5856 is a constant 1.27 mm (0.05 inch). The rear wall thickness 5856 allows energy from an impact to transfer to the inflection point 5886 to help induce a buckling effect.

[0269] The top wall 5719 is angled toward the strikeface and away from the top rail 5615 in a direction toward the first inflection point 5786. The top wall 5719 extends from the second reference point 5782 to the first inflection point 5786. The described configuration of the rear wall 5723 and top wall 5719 allows increased bending of the top rail 5615 of the club head 5600 on impact with a golf ball, compared with a club head devoid of the described rear and top wall configuration. The top wall 5719 connects to the indention wall 5821 at the first inflection point 5786.

[0270] The indention 5630 is formed by the top wall 5719, the indention wall 5821, and the ledge 5825. In some embodiments, the indention wall 5821 can be roughly planar. In some embodiments, the indention wall 5821 can comprise an at least partially curved profile, when viewed from a cross-sectional view, as shown in FIG. 44. An indention wall thickness 5858 is measured perpendicularly from the exterior surface 5603 to the interior surface 5819 at a point along the indention wall 5821 between the first inflection point 5786 and the second inflection point 5792. The indention wall thickness 5858 can range from 1.016 mm to 2.032 mm (0.040 inch to 0.080 inch). For example, the indention wall thickness 5858 can be 1.016 mm (0.040 inch), 1.143 mm (0.045 inch), 1.270 mm (0.050 inch), 1.397 mm (0.055 inch), 1.524 mm (0.060 inch), 1.651 mm (0.065 inch), 1.778 mm (0.070 inch), 1.905 mm (0.075 inch), or 2.032 mm (0.080 inch). In many embodiments, the indention wall thickness 5858 is constant with the rear wall thickness 5856 and a ledge thickness 5860. In other embodiments, the indention wall thickness 5858 can be less than the rear wall thickness 5856 and the ledge thickness 5860. The indention wall thickness 5858 being consistent with or less than the thickness 5823, 5860 of the rear wall 5723 and the ledge 5825 allows for more uniform energy transfer and bending.

[0271] As best understood from a rear view, such as FIG. 42, the indention wall 5821 can cover a surface area between 10% and 40% of the surface area of the rear 5610. For example, the indention wall 5821 can cover a surface area between 10% and 20%, 20% and 30%, or 30% and 40% of the surface area of the rear 5610. In some embodiments, the indention wall 5821 can cover a surface area approximately 29% of the surface area of the rear 5610.

[0272] A height 5888 of the indention 5630 is measured perpendicular to the ground plane 10 from the second reference point 5782 to the third inflection point 5794. The height 5888 of the indention 5630 can range from 3.81 mm (0.15 inch) to 27.94 mm (1.1 inch). For example, the height 5888 of the indention 5630 can range from 3.81 mm (0.15 inch) to 7.62 mm (0.30 inch), 7.62 mm (0.30 inch) to 11.43 mm (0.45 inch), 11.43 mm (0.45 inch) to 15.24 mm (0.60 inch), 15.24 mm (0.60 inch) to 19.05 mm (0.75 inch), 19.05 mm (0.75 inch) to 22.86 mm (0.90 inch), or 22.86 mm (0.90 inch) to 25.4 mm (1.0 inch). For example, the height 5888 of the indention 5630 can be approximately 5.33 mm (0.21 inch) in the heel region 5602, approximately 16.00 mm (0.63 inch) in a center of the club head between the heel region 5602 and the toe region 5604, and approximately 24.89 mm (0.98 inch) in the toe region 5604. In some embodiments, the maximum height 5888 of the indention is between 20.32 mm (0.80 inch) and 27.94 mm (1.1 inch).

[0273] The second inflection point 5792 comprises a second inflection angle measured from the indented wall 5721 to the ledge 5825. The second inflection angle of the second inflection point 5792 can range from at least 95 degrees to 150 degrees. In some embodiments, the second inflection angle 5796 can be at least 95 degrees, 100 degrees, 105 degrees, 110 degrees, 115 degrees, 120 degrees, 125 degrees, 130 degrees, 135 degrees, 140 degrees, 145 degrees, or 150 degrees. In some embodiments, the second inflection angle can be consistent from the heel region 5602 to the toe region 5604. In other embodiments, the second inflection angle 5796 can vary from the heel region 5602 to the toe region 5604. In many embodiments, the second inflection angle 5796 allows for the second inflection point 5686 to act as a buckling point or plastic hinge upon the golf club head 5600 impacting the golf ball at strikeface 5712.

[0274] As illustrated in FIG. 44, in some embodiments, the ledge comprises a ledge width 5829. The ledge width 5829 is measured along the ledge 5825 from the second inflection point 5792 to the third inflection point 5794. The ledge width 5829 can range from 2.235 mm to 3.251 mm (0.088 inch to 0.128 inch). For example, the ledge width 5829 can be 2.286 mm (0.090 inch), 2.388 mm (0.094 inch), 2.489 mm (0.098 inch), 2.540 mm (0.100 inch), 2.642 mm (0.104 inch), 2.743 mm (0.108 inch), 2.794 mm (0.110 inch), 2.845 mm (0.112 inch), 2.896 mm (0.114 inch), 2.997 mm (0.118 inch), 3.048 mm (0.120 inch), 3.150 mm (0.124 inch), or 3.251 mm (0.128 inch). In some embodiments, the ledge width 5829 can remain constant from the heel region 5602 to the toe region 5604. In other embodiments, the ledge width 5829 can vary from the heel region 5602 to the toe region 5604. For example, the ledge width 5829 can increase from the heel region 5602 to the toe region 5604. In other embodiments, the ledge width 5829 can decrease from the heel region 5602 to the toe region 5602.

[0275] The ledge 5825 comprises a ledge thickness measured perpendicularly from the exterior surface 5603 to the interior surface 5819 at a point along the ledge 5825 between the second inflection point 5792 and the third inflection point 5794. The ledge thickness can be similar to the indented wall thickness.

[0276] The upper region 5611 and the lower region 5613 of the rear 5610 are separated by the third inflection point 5794. In many embodiments, the third inflection point 5794 is positioned at least 40% down on the body 5601 below the apex 5828. For example, the third inflection point 5694 can be positioned 40%, 42%, 44%, 46%, 48%, 50%, 52%, 54%, 56%, 58%, 60%, 62%, 64%, 66%, 68%, or 70% down on the body 5601 below the apex 5828. The low positioned third inflection point 5794 allows for more leverage on the upper region 5611 to experience increased bending during impact with a ball, compared to a similar golf club head having a higher inflection point position.

[0277] The lower region 5613 of the body 5601 begins at the third inflection point 5794 and comprises a lower exterior wall 5827. The lower exterior wall 5827 extends from the first inflection point 5794 to the sole 5606. The lower exterior wall 5827 can be angled with respect to the strikeface. The lower region 5613 comprises a height measured from the ground plane 5703 to the third inflection point 5794 adjacent a lowest end of the ledge 5825. The lower region 5613 height can range between 10.16 mm and 30.48 mm (0.40 inch and 1.20 inch). For example, the lower region 5613 height can range between 10.16 mm and 17.78 mm (0.40 inch and 0.70 inch), 15.24 mm and 20.32 mm (0.60 inch and 0.80 inch), 17.78 mm and 22.86 mm (0.70 inch and 0.90 inch), 20.32 mm and 25.40 mm (0.80 inch and 1.00 inch), 22.86 mm and 27.94 mm (0.90 inch and 1.10 inch), or 25.40 mm and 30.48 mm (1.00 inch and 1.20 inch).

[0278] A third inflection angle 5851 is measured between the ledge 5825 and the lower exterior wall 5727, at the third inflection point 5794. In some embodiments, the third inflection angle 5851 can be less than 160 degrees. In a number of embodiments, the third inflection angle 5851 can be 90 degrees to 175 degrees. For example, the third inflection angle 5851 can be 90 degrees, 95 degrees, 100 degrees, 105 degrees, 110 degrees, 115 degrees, 120 degrees, 125 degrees, 130 degrees, 135 degrees, 140 degrees, 145 degrees, 150 degrees, 155 degrees, 160 degrees, 165 degrees, 170 degrees, or 175 degrees.

[0279] The lower exterior wall 5727 is located in the lower region 5613 of the club head 5600. The lower exterior wall 5727 extends downward from the third inflection point 5794 at an edge of the ledge 5825 to the sole of the club head 5600. A section of the lower exterior wall 5727 forms an outer rear edge of the solid region of the lower region 5613. The lower exterior wall 5727 bounds the rear of the club head 5600 below the ledge 5825.

[0280] FIG. 46 illustrates another cross-sectional view of the golf club head 5600, similar to the detailed cross-section of golf club head 5600 illustrated in FIG. 42. The internal cavity 5616 comprises a top cavity width 5993, a minimum cavity width (minimum gap) 5990, a maximum cavity width 6095, and a lower region cavity width 6097, all measured in a direction perpendicular from the strikeface 5612 from an interior surface 5819 of the strikeface 5612 to a back edge of the internal cavity 5616. The top cavity width 5993 is located above the minimum upper cavity width 5990. The region of the internal cavity 5616 having the greater top cavity width 5993 corresponds to the upper perimeter portion 5609. The portion of the internal cavity 5616 adjacent the minimum upper cavity width 5990 corresponds to the indention 5630. The top cavity width 5993 is above the minimum cavity width 5990, which is above the maximum cavity width 6095, which is above the lower region cavity width 6097. In some embodiments, the maximum cavity width 5990 is located in the lower region 5613 of the club head 5600. In many embodiments, the lower region 5613 of the body 5601 comprises a solid region adjacent the rear 5610. The solid region provides weighting to the rear 5610 of the club head 5600. This solid region causes the lower region cavity width 6097 to be less than a width of the cavity adjacent and below the indention 5630. The minimum cavity width 5990 can be between 20% and 55% of the lower region cavity width 6097 in a central portion of the club head 5600, such as is shown in the cross-section of FIG. 46. For example, the minimum cavity width 5990 can be 20%, 25%, 30%, 35%, 40%, 45%, or 50% of the lower region cavity width 6097.

[0281] The top cavity width 5993 is measured between the rear wall 5723 and a back surface of the strikeface 5612. In some embodiments, top cavity width 5993 can range from 2 mm (0.079 inch) to 6 mm (0.24 inch). For example, top cavity width can be 2 mm (0.079 inch), 3 mm (0.118 inch), 4 mm (0.16 inch), 5 mm (0.197 inch) or 6 mm (0.24 inch). In other embodiments, top cavity width can range from 3 mm (0.118 inch) to 4 mm (0.16 inch). In some embodiments, top cavity width can be 3.429 mm (0.135 inch).

[0282] In some embodiments, the minimum cavity width 5990 is located between the first inflection point 5786 and the back surface of the strikeface 5612. In some embodiments, the minimum cavity width 5990 is located between the indention wall 5821 and the back surface of the strikeface 5612. In some embodiments, the minimum cavity width 5990 can range from 2 mm (0.079 inch) to 6 mm (0.24 inch). For example, the minimum cavity width 5990 can be 2 mm (0.079 inch), 3 mm (0.118 inch), 4 mm (0.16 inch), 5 mm (0.197 inch), or 6 mm (0.24 inch). In other embodiments, the minimum cavity width 5990 can range from 3 mm (0.118 inch) to 4 mm (0.16 inch). In some embodiments, the minimum cavity width 5990 can be 3.429 mm (0.135 inch).

[0283] The maximum cavity width 6095 is located beneath the indention 5630. In some embodiments, maximum cavity width 6095 can range from 10.16 mm to 17.78 mm (0.40 inch to 0.70 inch). For example, the maximum cavity width can be 10.16 mm (0.40 inch), 11.43 mm (0.45 inch), 12.70 mm (0.50 inch), 13.97 mm (0.55 inch), 15.24 mm (0.60 inch), 16.51 mm (0.65 inch), or 17.78 mm (0.70 inch). In other embodiments, maximum cavity width 6095 can range from 13.97 mm to 15.24 mm (0.55 inch to 0.60 inch). In some embodiments, maximum cavity width 6095 can be 14.99 mm (0.59 inch).

[0284] The lower region cavity width 6097 is measured between the solid region and the interior surface 5819 of the strikeface 5612. In some embodiments, the lower region cavity width 6097 can range from 3.81 mm (0.15 inch) to 10.16 mm (0.40 inch). For example, the lower region cavity width 6097 can be 3.81 mm (0.15 inch), 5.08 mm (0.20 inch), 6.35 mm (0.25 inch), 7.62 mm (0.30 inch), 8.89 mm (0.35 inch), or 10.16 mm (0.40 inch). In other embodiments, the lower region cavity width 6097 can range from 6.86 mm (0.27 inch) to 7.87 mm (0.31 inch). In some embodiments, the top cavity width can be 7.37 mm (0.29 inch).

[0285] Referring again to FIG. 46, the body 5601 of golf club head 5600 further comprises an upper perimeter portion distance 6092, a minimum distance 6094, and a maximum distance 6096. The upper perimeter portion distance 6092 of the club head 5600 adjacent to the top rail 5615 is measured as the perpendicular distance from the exterior surface 5603 of the strikeface 5612 to the exterior surface 5603 of the rear wall 5623. The upper perimeter portion distance 6092 of the club head is between 7.747 mm and 8.255 mm (0.305 inch and 0.325 inch). In some embodiments, the upper perimeter portion distance 6092 of the club head is between 7.747 mm and 7.874 mm (0.305 inch and 0.310 inch), 7.874 mm and 8.001 mm (0.310 inch and 0.315 inch), 8.001 mm and 8.128 mm (0.315 inch and 0.320 inch), or 8.128 mm and 8.255 mm (0.320 inch and 0.325 inch). In some embodiments, the upper perimeter portion distance 6092 of the club head 5600 is greater than the ledge width 5829.

[0286] The minimum distance 6094 of the body 5601 is measured as the perpendicular distance from the exterior surface 5603 of the strikeface 5612 in the upper region 5611 to the exterior surface 5603 of the rear wall 5623. The minimum distance 6094 can range from 5.08 mm to 10.16 mm (0.20 inch to 0.40 inch). For example, the minimum distance 6094 can be 5.08 mm (0.20 inch), 5.59 mm (0.22 inch), 6.10 mm (0.24 inch), 6.60 mm (0.26 inch), 7.11 mm (0.28 inch), 7.62 mm (0.30 inch), 8.13 mm (0.32 inch), 8.64 mm (0.34 inch), 9.14 mm (0.36 inch), 9.65 mm (0.38 inch), or 10.16 mm (0.40 inch). In some embodiments, the minimum distance 6094 of the body 5601 can be greater than the ledge width 5829. The maximum distance 6096 of the body 5601 is measured as the perpendicular distance from the exterior surface 5603 of the strikeface 5612 to the exterior surface 5603 of the rear 5610. The maximum distance 6096 can range from 15.24 mm to 22.86 mm (0.60 inch to 0.90 inch). For example, the maximum distance 6096 can be 15.24 mm (0.60 inch), 16.26 mm (0.64 inch), 17.27 mm (0.68 inch), 18.29 mm (0.72 inch), 19.30 mm (0.76 inch), 20.32 mm (0.80 inch), 21.34 mm (0.84 inch), 22.35 mm (0.88 inch), or 22.86 mm (0.90 inch).

[0287] As illustrated in FIG. 44-48, the golf club head 5600 can be a hollow, or at least partially hollow body comprising an internal cavity 5616. Internal cavity 5616 of the body 5601 comprises a volume. The volume of the internal cavity 5616 can range from 10.65 cm³ (0.65 inch³) to 17.21 cm³ (1.05 inch³). In some embodiments, the internal cavity 5616 can comprise a volume of 10.65 cm³ (0.65 inch³), 11.47 cm³ (0.70 inch³), 12.29 cm³ (0.75 inch³), 13.11 cm³ (0.80 inch³), 13.93 cm³ (0.85 inch³), 14.75 cm³ (0.90 inch³), 15.57 cm³ (0.95 inch³), 16.39 cm³ (1.00 inch³), or 17.21 cm³ (1.05 inch). Similarly, material portion of the body 5601, void of the cavity 5616, further comprises a material volume. The material volume of the body 5601 can range from 40.97 cm³ (2.50 inch³) to 57.35 cm³ (3.50 inch³). For example, the material volume of the body 5601 can be 40.97 cm³ (2.50 inch³), 42.61 cm³ (2.60 inch³), 44.25 cm³ (2.70 inch), 45.88 cm³ (2.80 inch³), 47.52 cm³ (2.90 inch³), 49.16 cm³ (3.00 inch³), 50.80 cm³ (3.10 inch³), 52.44 cm³ (3.20 inch³), 54.08 cm³ (3.30 inch³), 55.72 cm³ (3.40 inch³), or 57.35 cm³ (3.50 inch³).

[0288] In many embodiments, the internal cavity 5616 of the body 5601 can be void of any substance. In other embodiments, the internal cavity 5616 of the body 5601 can comprise a polymer (not pictured), wherein the polymer can be at least partially filling the internal cavity 5616. The polymer can be polyethylene terephthalate, high-density polyethylene, polyvinyl chloride, polycarbonate, polypropylene, other thermoplastics, composites polymers or any combination thereof. The polymer can fill 10% to 80% 10% to 25%, 15% to 30%, 30% to 45%, 45% to 60%, 60% to 75%, 75% to 80%, 10% to 40%, 30% to 60%, or 40% to 80% of the internal cavity 5616 of the body 5601. For example, the polymer can fill 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, or 85% of the internal cavity 5616 of the body 5601. In some embodiments, the polymer fills 80% of the internal cavity 5616 of the body 5601.

[0289] The polymer at least partially filling the internal cavity 5616 of the body 5601 can comprise a specific gravity ranging from 0.05 to 4. For example, the specific gravity of the polymer can be 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, or 4. In some embodiments, the specific gravity of the polymer is proportional to the mass of the polymer, wherein 1 specific gravity of the polymer is equal to 1 gram. Similarly, in those exemplary embodiments, the volume is proportional to the polymer specific gravity, wherein 1 specific gravity of the polymer is equal to 1 cc. In other embodiments, the volume is not proportional to the specific gravity of the polymer. For example, the ratio of the polymer specific gravity to the polymer volume can be 2:1 cc, 2:3 cc, 2:4 cc, 3:1 cc, 3:2 cc, 3:4 cc, 4:1 cc, 4:2 cc, or 4:3 cc.

[0290] The mass of the polymer allows for the swing weight of the golf club head 4400 to be customizable for each player. Increasing the volume of the polymer, and thus the mass, increases the swing weight. Similarly, decreasing the volume of the polymer decreases the swing weight. Having the appropriate swing weight for each individual player improves feel during a swing and can improve performance such as swing speed, swing path, ball speed, and ball trajectory. The polymer can further increase the overall mass of the golf club head 5600 more toward the sole 5606. Increasing the mass more toward the sole shifts the CG low and back, thereby improves the moment of inertia.

[0291] The strikeface 5612 can be coated with a durable finish. For example, the strikeface 5612 can be coated with Hydropearl 2.0 chrome plate finish or a high polished chrome. In some embodiments, the strikeface 5612 is further finished with brushing or blasting. The golf club head 5600 can further comprise a vibration damping layer 5878 on the interior surface 5819 of the strikeface 5612. The vibration damping layer 5878 can be formed from an elastomer material or any other suitable material. For example, the vibration damping layer 5878 can be formed from a urethane and graphene coating, a urethane coating, or a silicone gel. The vibration damping layer 5878 can have a weight of 1-7 grams. For example, the vibration damping material can have a weight of 1 gram, 3 grams, 5 grams, or 7 grams. The vibration damping layer 5878 can fill between 10%-30% of the volume of the internal cavity of the club head 5600. The vibration damping layer 5878 can partially or fully cover the interior surface 5819 of the strikeface 5612. The thickness of the vibration damping layer 5878, measured perpendicular to the strikeface 5612, can either vary or be uniform across the interior surface 5819 of the strikeface 5612.

[0292] In some embodiments, the golf club head 5600 can further comprise an aperture 5634 located on the toe region 5604. The aperture 5634 comprises internal threads and is configured to receive a threaded screw weight 5637, as seen in FIG. 42. FIG. 42 illustrates the threaded screw weight 5637 removed from the aperture 5634 but positioned for insertion into the aperture 5634. The threaded screw weight 5637 comprises a mass, wherein the mass of the threaded screw weight 5637 can range from 2 grams to 12 grams. In other embodiments, the mass of the threaded screw weight 5637 can range from 4 grams to 10 grams. In some embodiments, the screw weight 5637 can weight 2 grams, 3 grams, 4 grams, 5 grams, 6 grams, 7 grams, 8 grams, 9 grams, 10 grams, 11 grams, 12 grams, 13 grams, or 14 grams. The mass of the screw weight 5637 correlates with the length of the screw weight 5637, wherein a longer threaded screw weight 5637 equates to a greater mass. The threaded screw weight 5637 further affects the mass and overall swing weight of the golf club head 5600. Therefore, the threaded screw weight 5637 can improve the feel of the golf club head 5600, as well as performance characteristics (e.g., swing speed, ball speed, and ball flight).

[0293] The hosel of the club head 5600 can house a tip weight 5638. FIG. 42 depicts the tip weight 5638 removed from the hosel, but in position for insertion into the hosel. The tip weight 5638 can have a weight that ranges between 0.1 and 10 grams. For example, the tip weight 5638 can have a weight of 0.2, 0.4, 0.6, 0.8, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 grams.

[0294] Although both the toe slit 5666 and heel slit 5662 affect the deflection of the club head 5600, the toe slit 5666 has a greater effect on the deflection. The slits 5666, 5662 reduce concentrated stresses at toe and heel junctions between the lower region 5613 and the upper perimeter portion 5609 and spread impact stresses across a greater volume of the club body 5601. The toe and heel slits 5666, 5662 allow structural bending between the upper region 5611 and the lower region 5613 of the club head 5600, which results in greater deflection of the strikeface 5612 than would be present in a similar golf club head lacking toe and/or heel slits. The slits 5666, 5662 can increase the bending between the lower region 5613 and the upper region 5611 around the second inflection point 5792. The greater deflection of the strikeface 5612 provides a higher dynamic loft angle to the golf club 5600. The loft angle is an acute angle measured from the strikeface 5612 to a ground reference plane 10. By dynamically increasing the deflection of the club head 5600, the conventional loft angle can be lowered without sacrificing trajectory. For example, a first club head with a loft angle lower than a second club head can have a trajectory equal to the trajectory of the second club head if the first club head comprises slits that increase the deflection of the club head. In some embodiments, the conventional loft angle can be reduced by up to 0.6 degrees, up to 0.5 degrees, or up to 0.4 degrees. The lower loft of the first club head can result in a higher ball speed for a golf ball impacted by the club head due to the lower loft angle of the first club. The gapping between clubs in a set can be more uniform in a club head set that comprises the slits disclosed herein.

[0295] Furthermore, in many embodiments, indention 5630 can provide an increase in golf ball speed over ball speeds of standard golf club heads and can increase the launch angle over both the standard hybrid and iron club heads. A golf club head lacking the indention 5630 cannot buckle in a controlled manner during impact or spring back like a drum after impact as well as the club head 5600. The first, second, and third inflection points 5786, 5792, and 5794 allow the body 5601 to bend backwards when a golf ball impacts the strikeface in a manner not possible for a golf club head lacking these inflection points.

[0296] The upper perimeter portion can provide spring to the back end of the club and exhibit low peak stress concentrations. The interaction of the strikeface 5612, the top rail 5615, the rear wall 5723, and the top wall 5719 is affected by the strikeface angle 5950, the top rail angle 5945, and the rear angle 5940. The strikeface 5612, the top rail 5615, the rear wall 5723, and the top wall 5719 interact and benefit the hinging of the club head in a manner similar to the respective components of golf club head 3700 described above.

[0297] The uniform thinned region 6060 on the sole 5606, described above, can provide multiple benefits, similar to those described above for the uniform thinned regions of golf club heads 2200, 2700, 3200, 3700, 4400, and 4900.

[0298] In some embodiments, body 5601 can comprise stainless steel, , titanium, aluminum, a steel alloy (e.g. 455 steel, 475 steel, 431 steel, 17-4 stainless steel, maraging steel), a titanium alloy (e.g. Ti 7-4, Ti 6-4, T-9S, Ti SSAT2041, Ti SP700, Ti 15-0-3, Ti 15-5-3, Ti 3-8-6-4-4, Ti 10-2-3, Ti 15-3-3-3, Ti-6-6-2, Ti-185, or any combination thereof), an aluminum alloy, or a composite material. In other embodiments, body 5601 can comprise carpenter grade 455 steel, carpenter grade 475 steel, C300 steel, C350 steel, a Ni-Co-Cr steel alloy, a quench and tempered steel alloy, or 565 steel. In some embodiments, strikeface 4412 can comprise stainless steel, titanium, aluminum, a steel alloy (e.g. 455 steel, 475 steel, 431 steel, 17-4 stainless steel, maraging steel), a titanium alloy (e.g. Ti 7-4, Ti 6-4, T-9S, Ti SSAT2041, Ti SP700, Ti 15-0-3, Ti 15-5-3, Ti 3-8-6-4-4, Ti 10-2-3, Ti 15-3-3-3, Ti-6-6-2, Ti-185, or any combination thereof), an aluminum alloy, or a composite material. In other embodiments, strikeface 4412 can comprise carpenter grade 455 steel, carpenter grade 475 steel, C300 steel, C350 steel, a Ni-Co-Cr steel alloy, a quench and tempered steel alloy, or 565 steel. In some embodiments, body 5601 can comprise the same material as strikeface 5612. In some embodiments, body 5601 can comprise a different material than strikeface 5612.

II. Golf Club Head with Partial Back Cavity

[0299] FIGS. 49-60D illustrate a golf club head 7100 according to the claimed invention that includes a partial back cavity 7102 and a rear opening 7104 according to embodiments of the present invention. In the illustrated embodiment, the club head 7100 is an iron-type club head 7100. The club head 7100 includes a body 7106, a faceplate 7108 coupled to the body 7106 at a front end 7110 and defining a striking surface or strikeface 7112, and a cover or badge 7114 coupled to the body 7106 at a back end 7116 opposite the front end 7110. In some embodiments, body 7106 can be similar to body 1001 (FIG. 1), body 2201 (FIG. 8), body 2701 (FIG. 13), body 3201 (FIG. 18), body 3701 (FIG. 23), and/or body 4401 (FIG. 30). In some embodiments as will be described below, the badge 7114 may be a partial badge 7114 (FIGS. 59A-59C), or the badge 7114 may be omitted entirely from the club head 7100 (FIG. 59D). In addition to the front end 7110 and the back end 7116, the body 7106 includes a heel region 7118, a toe region 7120 opposite the heel region 7118, a sole 7122, and a top rail 7124 opposite the sole 7122. The body 7106 also includes a hosel 77126 proximate the heel region 7118 for coupling the golf club head 7100 to a shaft (not shown) to form a golf club.

[0300] With reference to FIG. 52, the rear opening 7104 is defined by the body 7106 and is formed in the back end 7116. The body 7106 further defines a front opening 7128 formed in the front end 7110 and located opposite the rear opening 7104. The faceplate 7108 covers and closes the front opening 7128. In some embodiments as will be described below, the badge 7114 partially covers and closes the rear opening 7104. The faceplate 7108 and the body 7106 together define the partial back cavity 7102. The partial back cavity 7102 is also described as a partially closed internal space formed within the body 7106 and partially bounded by the faceplate 7108. The partial back cavity 7102 is referred to herein as 'partial' in the sense that it remains partially open to the exterior of the club head 7100 due to the existence of the rear opening 7104, which communicates the partial back cavity 7102 with the exterior of the club head 7100. In other embodiments (not shown), the body 7106 can be formed integrally with a faceplate such that the body alone defines the partial back cavity 7102.

[0301] With reference to FIGS. 54 and 55, the body 7106 also defines an open external cavity 7130, hereafter referred to as an indention 7130, extending inward from the back end 116 toward the front end 7110 and toward the strikeface 7112. The rear opening 7104 is formed within the indention 7130. The indention 7130 alters the deflection and/or weighting of the club head 7100. Specifically, the indention 7130 allows the club head 7100 to buckle in a controlled manner during impact with a golf ball, or spring back like a drum after impact. Thus, the indention 7130 can provide a relative increase in golf ball speed and in launch angle as compared to known prior art iron-type golf club heads.

[0302] With reference to FIGS. 55 and 58, the body 7106 includes a back wall 7132 formed at the back end 7116. The back wall 7132 surrounds and defines the indention 7130 and generally extends between the top rail 7124 and the sole 7122, and between the heel region 7118 and the toe region 7120. The back wall 7132 is further divided into an upper back wall 7134 formed adjacent the top rail 7124, and a lower back wall 7136 formed adjacent the sole 7122. The upper back wall 7134 extends downward from the top rail 7124 to a top ledge or top cavity wall 7138. In the illustrated embodiment, the upper back wall 7134 is generally parallel to the strikeface 7112. In other embodiments, the upper back wall 7134 can generally slope toward or away from the strikeface 7112 as the upper back wall 7134 extends from the top rail 7124 to the top cavity wall 7138. The lower back wall 7136 extends upward from the sole 7122 to a bottom ledge or bottom cavity wall 7140. In the illustrated embodiment, the lower back wall 7136 generally slopes away from the strikeface 7112 as the lower back wall 7136 extends from the sole 7122 toward the bottom cavity wall 7140. In other embodiments, the lower back wall 7136 can be generally parallel to the strikeface 7112 or the lower back wall 7136 can slope toward the strikeface 7112.

[0303] With continued reference to FIG. 58, the top cavity wall 7138 extends from the upper back wall 7134 to an upper indention wall 7142 in a direction generally toward the strikeface 7112. The top cavity wall 7138 generally follows the contour of the top rail 7124 as the top cavity wall 138 extends between the heel region 7118 and the toe region 7120. The bottom cavity wall 7140 extends from the lower back wall 7136 to a lower indention wall 7144 in a direction generally toward the strikeface 7112. The bottom cavity wall 7140 generally follows the contour of the sole 7122 as the bottom cavity wall 7140 extends between the heel region 7118 and the toe region 7120, except that the bottom cavity wall 7140 includes a stepped portion 146 (FIG. 54) located toward the toe region 7120 that steps upward toward the top rail 124.

[0304] A rear opening rim 7148 (FIG. 54) further defines and circumscribes the rear opening 7104. The rear opening rim 7148 is divided into an upper rim 7150 located closer to the top rail 7124, and a lower rim 7152 located closer to the sole 7122 (FIGS. 57, 58). The upper rim 7150 generally follows the contour of the top rail 7124 and of the top cavity wall 7138. The lower rim 7152 generally follows the contour of the bottom cavity wall 7140, and can include a generally linear, arcuate, or segmented extent (e.g., a step-wise extent) as the lower rim 7152 extends between the heel region 7118 and the toe region 7120. The upper indention wall 7142 extends from the top cavity wall 7138 to the upper rim 7150 of the rear opening 7104, in a direction generally toward the sole 7122. The upper indention wall 7142 is generally parallel to the upper back wall 7134. The upper indention wall 7142 is also generally parallel to the strikeface 7112. In other embodiments, the upper indention wall 7142 can slope generally away from the strikeface 7112 as the upper indention wall 7142 extends from the top cavity wall 7138 to the upper rim 7150. The lower indention wall 7144 extends from the bottom cavity wall 7140 to the lower rim 7152 of the rear opening 7104, in a direction generally toward the top rail 7124. The lower indention wall 7144 generally slopes toward the strikeface 7112 as the lower indention wall 7144 extends from the bottom cavity wall 7140 to the lower rim 7152. Together, the top and bottom cavity walls 7138, 7140 and the upper and lower indention walls 7142, 7144 cooperate to define the indention 7130. In some embodiments, the badge 7114 can be adhered to the upper rim 7150 and the lower rim 7152.

[0305] With continued reference to FIG. 58, the body 7106 further includes a front wall 7154 formed at the front end 7110. The front wall 7154 surrounds the front opening 7128 and generally extends between the top rail 7124 and the sole 7122, and between the heel region 7118 and the toe region 7120. The front wall 7154 is further divided into an upper front wall 7156 formed adjacent the top rail 7124, and a lower front wall 7158 formed adjacent the sole 7122. A front opening rim 7160 defines and circumscribes the front opening7 128. The upper front wall 7156 extends downward from the top rail 7124 to the front opening rim 7160. In the illustrated embodiment, the upper front wall 7156 is generally parallel to the strikeface 7112. The lower front wall 7158 extends upward from the sole 7122 to the front opening rim 7160. In the illustrated embodiment, the lower front wall 7158 is also generally parallel to the strikeface 7112.

[0306] The body 7106 also includes a top rail wall 7162 that extends across the top rail 7124 between the upper front wall 7156 and the upper back wall 7134. The top rail wall 7162 includes a smoothly curved contour as the top rail wall 7162 extends between the upper front wall 7156 and the upper back wall 7134. The body 7106 further includes a bottom wall 7164 that extends across the sole 7122 between the lower front wall 7158 and the lower back wall 7136. The bottom wall 7164 includes a smoothly curved contour as the bottom wall 7164 extends between the lower front wall 7158 and the lower back wall 7136.

[0307] A portion of the bottom wall 7164 adjacent the lower front wall 7158 defines a uniform thinned region 7166. The uniform thinned region 7166 has a sole thickness 7168, measured perpendicular to an exterior surface of the bottom wall 7164 and between the exterior surface and an interior surface thereof. The sole thickness 7168 is relatively thinner as compared to the thicknesses of the remaining portions of the bottom wall 7164. The sole thickness 7168 is also relatively thinner as compared to that of known prior art iron-type clubs. In some embodiments, the sole thickness may range from approximately 1.02 mm to 2.03 mm (0.040 inch to 0.080 inch). In other embodiments, the sole thickness 7168 may be within the range of 1.02 mm to 1.27 mm (0.040 inch to 0.050 inch), 1.27 mm to 1.52 mm (0.050 inch to 0.060 inch), 1.52 mm to 1.78 mm (0.060 inch to 0.070 inch), 1.78 mm to 2.03 mm (0.070 inch to 0.080 inch), 1.02 mm to 1.40 mm (0.040 inch to 0.055 inch), 1.14 mm to 1.52 mm (0.045 inch to 0.060 inch), 1.27 mm to 1.65 mm (0.050 inch to 0.065 inch), 1.40 mm to 1.78 mm (0.055 inch to 0.070 inch), 1.52 mm to 1.91 mm (0.060 inch to 0.075 inch), or 1.65 mm to 2.03 mm (0.065 inch to 0.080 inch). For example, the sole thickness 7168 can be 1.02 mm (0.040 inch), 1.14 mm (0.045 inch), 1.27 mm (0.050 inch), 1.52 mm (0.060 inch), 1.65 mm (0.065 inch), 1.78 mm (0.070 inch), 1.91 mm (0.075 inch), or 2.03 mm (0.080 inch).

[0308] With reference to FIGS. 57 and 58, the partial back cavity 7102 includes an upper channel 7170 defined within the top rail 7124 of the body 7106 and generally extending lengthwise across the club head 7100 between the heel region 7118 and the toe region 7120. The upper channel 7170 is bounded between the top cavity wall 7138 and the top rail wall 7162, and between the faceplate 7108 and the upper back wall 7134. Due in part to the upper channel 7170, the top rail wall 7162 and the upper back wall 7134 cooperate to define a first buckling or first hinge region 7172 of the body 7106. The first hinge region 7172 experiences increased bending as compared to other regions of the body 7106 when the strikeface 7112 impacts a golf ball. The first hinge region 7172 allows the top rail 7124 to dynamically deflect to a greater extent as compared to known prior art iron-type club heads and enables the top rail 7124 to react to the impact force over a wider volumetric area of the body 7106. In turn, the top rail 7124 acts as a springboard by returning more recoiled force back to the faceplate 7108 as the top rail 7124 returns to its original orientation, thereby imparting more energy into the golf ball.

[0309] The deflection of the top rail 7124 also causes the faceplate 7108 to deflect to a greater extent during impact with the golf ball, leading to less spin, a higher loft angle, and greater ball speed for a given club speed as compared to standard iron-type golf club heads. As the first hinge region 7172 bends during impact, the faceplate 7108 deflects, causing a loft angle (defined between the strikeface 7112 and a ground plane with the golf club head 7100 at an address position) to increase relative to that of the club head 7100 at rest. The resting state loft angle of the club head 7100 (prior to impact with the golf ball) is reduced relative to that of typical prior-art iron-type club heads. This reduction of the resting state loft angle accounts for the deflection of the top rail 7124 at the hinge region 7172, and the resultant, dynamically-increased loft angle experienced while striking a golf ball. In some embodiments, the resting state loft angle can be reduced by up to 0.6 degrees as compared to known prior art iron-type club heads and still achieve a comparable launch angle of the golf ball during impact. Moreover, the club head 7100 including the relatively reduced loft angle can achieve a relatively higher ball speed due to the reduced loft angle.

[0310] With continued reference to FIGS. 57 and 58, the partial back cavity 7102 also includes a lower channel 7174 defined within the sole 7122 of the body 7106 and generally extending lengthwise across the club head 7100 between the heel region 7118 and the toe region 7120. The lower channel 7174 is bounded between the bottom cavity wall 7140 and the bottom wall 7164, and between the faceplate 7108 and the lower back wall 7136. Due in part to the lower channel 7174, uniform thinned region 7166 defines a second buckling or hinge region 7176 of the body 7106. Much like the first hinge region 7172, the second hinge region 7176 experiences increased bending as compared to other regions of the body 7106 when the golf club head 7100 impacts a golf ball. The second hinge region 7176 dynamically deflects to a greater extent as compared to known prior art iron-type club heads and enables the sole 7122 to react to the impact force over a wider volumetric area of the body 7106. In turn, the sole 7122 acts as a springboard by returning more recoiled force back to the faceplate 7108 as the sole 7122 returns to its original orientation, thereby imparting more energy into the golf ball.

[0311] With reference to FIG. 53, the body 7106 also includes a solid region 7178 located toward the toe region 7120, the sole 7122, and the back end 7116 of the body 7106. The solid region 7178 includes a relatively greater volume of the material forming the body 7106 as compared to other regions of the body 7106. Thus, the solid region 7178 has a relatively greater mass as compared to other regions of the body 7106 and provides perimeter weighting to the club head 7100.

[0312] With reference to FIGS. 52 and 53, an external toe cavity 7180 is formed within the body 7106. The toe cavity 7180 is located generally within the solid region 7178, toward the toe region 7120 and the sole 7122. The toe cavity 7180 is cylindrical in shape for receiving a cylindrical toe weight 7182. In some embodiments, the toe cavity 7180 is threaded for receiving a threaded toe weight 7182. In other embodiments, the toe weight 7182 is swedged into the toe cavity 7180. In other embodiments, the toe cavity 7180 can be trapezoidal in shape for receiving a non-cylindrical toe weight 7182. The body 7106 can include multiple toe cavities for receiving multiple weights. The toe cavity 7180 extends through the solid region 7178 to connect with the partial back cavity 7102. In other embodiments, the toe cavity 7180 extends partially into the solid region 7178 but does not extend to the partial back cavity 7102. In some embodiments, the toe weight 7182 can have a mass between 2 and 14 grams. The toe weight 7182 improves the swing weight and overall feel of the golf club head 7100, as well as other performance characteristics (e.g., swing speed, ball speed, and ball flight).

[0313] With reference to FIG. 55, the strikeface 7112 is generally flat and has a centerpoint 7184 located at a geometric center of the strikeface 7112. A midplane 7188 coincident with the centerpoint 7184 extends perpendicular to the strikeface 7112 to generally divide the club head 7100 into an upper region and a lower region. The rear opening 7104 is located above the midplane 7188, so that the rear opening 7104 is located between the midplane 7188 and the top rail 7124.

[0314] With reference to FIG. 58, an area of the rear opening is circumscribed and defined by the rear opening rim 7148. A projected area 7189 of the rear opening 7104 is defined by projecting the area of the rear opening 7104 onto the strikeface 7112 along a direction parallel to the midplane 7188, as shown by the dashed lines in FIG. 58. The midplane 7188 divides the strikeface 7112 into an upper region 7112A located above the midplane 7188 and closer to the top rail 7124, and a lower region 7112B located below the midplane 7188 and closer to the sole 7122. The projected area 7189 of the rear opening 7104 is located on the upper region 7112A. In accordance with the claimed invention, 100% of the projected area 7189 is located on the upper region 7112A.

[0315] The strikeface 7112 is coated with a durable finish (e.g., Hydropearl 2.0 chrome plate finish or a high polished chrome). In some embodiments, the strikeface 7112 is further finished with brushing or blasting. The golf club head 7100 also includes a vibration damping layer 7190 applied to an interior surface of the faceplate 7108. The vibration damping layer 7190 is formed from an elastomer material (e.g., a urethane and graphene coating, a urethane coating, a silicon gel, etc.). The vibration damping layer 7190 can alter and/or reduce the sound (e.g., "clank" or "pinging" noises) generated as the strikeface 7112 impacts the golf ball. The vibration damping layer 7190 can weigh between 1-7 grams and can fill between 10%-30% of the volume of the partial back cavity 7102 of the club head 7100. The vibration damping layer 7190 can partially or fully cover the interior surface of the faceplate 7108. The thickness of the vibration damping layer 7190, measured perpendicular to the faceplate 7108, can either vary or be uniform across the interior surface of the faceplate 7108.

[0316] With reference to FIGS. 60A-60D, the partial back cavity 7102 of the club head 7100 can be filled with a vibration damping filler material 7192. In some embodiments, the entire volume of the partial back cavity 7102 is completely filled with the filler material 7192 (FIG. 60A). In other embodiments, most of the volume of the partial back cavity 7102 (FIG. 60B), or approximately one half of the volume (e.g., a lower half of the volume) (FIG. 60C), or approximately one quarter of the volume (e.g., the lower one quarter of the volume) (FIG. 60D) of the partial back cavity 7102 is filled with the filler material 7192. In other embodiments, the filler material 7192 can fill 10% to 80%, 10% to 25%, 15% to 30%, 30% to 45%, 45% to 60%, 60% to 75%, 75% to 80%, 10% to 40%, 30% to 60%, or 40% to 80% of the partial back cavity 7102. For example, the filler material 7192 can fill 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, or 85% of the partial back cavity 7102. In some embodiments, the filler material 7192 fills 80% of the partial back cavity 7102. In yet other embodiments, the partial back cavity 7102 does not contain the filler material.

[0317] The filler material 7192 can be a synthetic polymer elastomer (e.g., polyethylene terephthalate, high-density polyethylene, polyvinyl chloride, polycarbonate, polypropylene, hot melt, other thermoplastics, composites, polymers or any combination thereof). In other embodiments, the filler material 7192 can be a natural polymer (e.g., rubbers, natural polymers derived from feathers, etc.), or the filler material 7192 can be a non-polymer material (e.g., quartz or other minerals). The filler material 7192 can have a specific gravity ranging from 0.05 to 4. For example, the specific gravity of the filler material 7192 can be 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, or 4. In some embodiments, the specific gravity of the filler material 7192 is proportionally equal to the mass of the filler material 7192, where 1 specific gravity of the filler material 7192 is equal to 1 gram. Similarly, in those exemplary embodiments, the volume occupied by the filler material 192 is proportionally equal to the specific gravity of the filler material 7192, wherein 1 specific gravity of the filler material 7192 is equal to 1 cc. In other embodiments, the volume is proportionally greater or less than the specific gravity of the filler material 192. For example, the ratio of the specific gravity to the volume of the filler material 192 can be 2:1 cc, 2:3 cc, 2:4 cc, 3:1 cc, 3:2 cc, 3:4 cc, 4:1 cc, 4:2 cc, or 4:3 cc.

[0318] The mass of the filler material 7192 allows a swing weight of the golf club head 7100 to be customizable for each player. Increasing the volume of the filler material 7192 that occupies the open back cavity 7102 increases the overall mass of the club head 7100, and thus increases the swing weight thereof. Similarly, reducing the volume of the filler material 7192 that occupies the open back cavity 7102 reduces the swing weight of the club head 7100. Achieving the appropriate swing weight of the club head 7100 for each individual player improves the feel of the golf club during a swing and can improve performance by optimizing swing speed, swing path, ball speed, and ball trajectory. The filler material 7192 can further concentrate the mass of the golf club head 7100 more toward the sole 7122. Concentrating the mass more toward the sole 7122 shifts a center of gravity (CG) of the club head 100 toward the sole 7122 and toward the back end 7116, thereby improving a moment of inertia (MOI) of the club head measured about an axis defined by the hosel 7126 of the club head 7100.

[0319] The rear opening 7104 provides access to the partial back cavity 7102 for applying the vibration damping layer 7190 to the back surface of the faceplate 7108. In those embodiments that include the filler material 7192, the rear opening 7104 also provides access to the partial back cavity 102 for depositing the filler material 7192 into the partial back cavity 7102.

[0320] As those illustrated in FIGS. 59A-59C, the badge 7114 is a partial badge 7114 that only covers a portion of the rear opening 7104. For example, the partial badge 7114 can cover an upper portion of the rear opening 7104 adjacent the upper rim 7150 (FIG. 59A), leaving a lower portion of the rear opening 7104 uncovered. In other embodiments, the partial badge 7114 can cover a lower portion of the rear opening 7104 adjacent the lower rim 7152 (FIG. 59B), leaving an upper portion of the rear opening 7104 uncovered. In further embodiments, the partial badge 7114 can include a central aperture 7196 (FIG. 59C) such that a central region of the rear opening 7104 remains uncovered. In some embodiments, the badge 7114 is permanently affixed to body 7106, while in other embodiments the badge 7114 is selectively removable. Embodiments including the selectively removable badge 7114 can provide a user more flexibility in customizing the type and volume of filler material 7192 deposited within the partial back cavity 7102. Other embodiments of the club head 7100 do not include the badge (FIG. 59D), such that the rear opening 7104 remains uncovered.

[0321] In some embodiments, the body 7106 is formed from 17-4 stainless steel. In other embodiments, the body 7106 can be formed from titanium, aluminum, another steel alloy (e.g. 455 steel, 475 steel, 431 steel, maraging steel), a titanium alloy (e.g. Ti 7-4, Ti 6-4, T-9S, Ti SSAT2041, Ti SP700, Ti 15-0-3, Ti 15-5-3, Ti 3-8-6-4-4, Ti 10-2-3, Ti 15-3-3-3, Ti-6-6-2, Ti-185, or any combination thereof), an aluminum alloy, or a composite material. In other embodiments, the body 7106 can be formed from carpenter grade 455 steel, carpenter grade 475 steel, C300 steel, C350 steel, a Ni-Co-Cr steel alloy, a quench and tempered steel alloy, or 565 steel.

[0322] The faceplate 7108 is formed from C300 steel. In other embodiments, the faceplate 108 can be formed from stainless steel, titanium, aluminum, another steel alloy (e.g. 455 steel, 475 steel, 431 steel, 17-4 stainless steel, maraging steel), a titanium alloy (e.g. Ti 7-4, Ti 6-4, T-9S, Ti SSAT2041, Ti SP700, Ti 15-0-3, Ti 15-5-3, Ti 3-8-6-4-4, Ti 10-2-3, Ti 15-3-3-3, Ti-6-6-2, Ti-185, or any combination thereof), an aluminum alloy, or a composite material. In other embodiments, the faceplate 108 can be formed from carpenter grade 455 steel, carpenter grade 475 steel, C300 steel, C350 steel, a Ni-Co-Cr steel alloy, a quench and tempered steel alloy, or 565 steel. In the disclosed embodiment, the body 7106 is formed from a different material than the faceplate 7108. In other embodiments, the body 7106 can be formed from the same material as the faceplate 7108.

[0323] In some embodiments, the badge 7114 is formed from aluminum. In other embodiments, the badge 7114 can be formed from other metals (e.g., titanium, metal alloys, etc.), or non-metals (e.g. polymers, elastomers, composites, wood, etc.). The material forming the badge 7114 has a lower density than that of the material forming the body 7106, resulting in relatively more perimeter weighting of the club head 7100 as compared to that of prior-art iron-type club heads. The material forming the badge 7114 can have a specific gravity between approximately 0.1 and 8.0.

[0324] The body 7106 is formed by casting. The front and rear openings 7128, 7104 of the body 7106 simplify the casting process by reducing tight contours and eliminating undercuts and similar geometries. The faceplate 7108 can be cast, stamped (punched), machined, or otherwise formed. The badge 7114 can be cast, molded, or stamped. During manufacturing of the club head 7100, the faceplate 7108 is swedged or welded onto the body 7106. The damping layer 7190 and the filler material 7192 are inserted, injected, sprayed, or otherwise deposited into the partial back cavity 7102 via the rear opening 7104, and then the badge 7114 is subsequently adhered, welded, snap-fit, or otherwise secured to the body 7106 to cover the rear opening 7104. Other stages, such as polishing or painting, can also be performed as part of the manufacturing process.

[0325] The golf club heads with energy storage characteristics discussed herein may be implemented in a variety of embodiments, and the foregoing discussion of these embodiments does not necessarily represent a complete description of all possible embodiments. Rather, the detailed description of the drawings, and the drawings themselves, disclose at least one preferred embodiment of golf club heads with energy storage characteristics, and may disclose alternative embodiments of golf club heads with tiered internal thin sections.

EXAMPLES

Example 1: Cavity Back vs. Hollow Body/Inflection Point Golf Club

[0326] Referring to Table 1 below, the exemplary club head 3700 being a hollow bodied iron club head with an inflection point 3986 was compared to two control club head (hereafter "Control 1" and "Control 2"). Control 1 and Control 2 were cavity back iron club heads that were similar in size and loft angle to exemplary club head 3700, but were devoid of an inflection point. Control 2 has a more pronounced cavity and wider sole than Control 1. Ball speed (measured in mph), launch angle (measured in degrees), carry distance (measured in m), and spin rate (measured in rpm) were measured between the exemplary club head 3700, Control 1, and Control 2.

Table 1: Performance of Club Head 3700 vs. Control Club Heads 1 and 2

	Average Ball Speed (mph)	Average Launch Angle (degrees)	Average Spin Rate (rpm)	Average Carry Distance (m)
Club Head 3700	127.3	15.9	5931	176.5 (193 yards)
Control 1	127.6	15.4	5972	173.7 (190 yards)
Control 2	126.3	15.8	6551	169.2 (185 yards)

[0327] As shown in Table 1, the exemplary club head 3700 having a hollow body and inflection point 3986 produced an average ball speed of 127.3 mph, an average launch angle of 15.9 degrees, an average carry distance of 176.5 m (193 yards), and an average spin rate of 5931 rpm. Comparatively, Control 1 produced an average ball speed of 127.6 mph, an average launch angle of 15.4 degrees, an average carry distance of 173.7 m (190 yards), and an average spin rate of 5972 rpm, and Control 2 produced an average ball speed of 126.3 mph, an average launch angle of 15.8 degrees, an average carry distance of 169.2 m (185 yards), and an average spin rate of 6551 rpm. Although the exemplary club head 3700 experienced a decrease of about 0.2% in average ball speed compared to Control 1 and an increase of about 0.8% to 1% in average ball speed compared to Control 2, the average launch angle and average spin rate increased the average carry distance farther due to the hollow body and inflection point 3986 of the exemplary club head 3700. The exemplary club head 3700 experienced a 3.25% increase in the average launch angle compared to Control 1, and a 0.6% to 1% increase in the average launch angle compared to the Control 2 respectively. Further, the exemplary club head 3700 experienced around a 0.7% decrease in average spin rate compared to Control 1 and a 9.46% decrease in average spin rate compared to Control 2 respectively. The increased average launch angle and decreased average spin rate of the exemplary club head 3700 compared to the Control 1 and 2 increased the carry distance of the ball during impact. More specifically, the exemplary club head 3700 experienced a 1.58% compared to Control 1 and 4.32% increase in average carry distance of the ball compared to Control 1 and Control 2. Therefore, the hollow body and inflection point 3986 of the exemplary club head 3700 increases the bending of the strikeface 3712 to produce optimal ball performance characteristic compared to similar sized club heads devoid of an inflection point.

Example 2: Cavity Back vs. Hollow Body/Inflection Point Golf Club

[0328] Referring to Table 2 below, the exemplary club head 4400 being a hollow bodied iron club head with an inflection point 4686 that is 55% from the top rail apex to the inflection point of the club head 4400 was compared to a control club head (hereafter "Control Club Head"). Control Club Head was a cavity back iron club head similar in size and loft angle to exemplary club head 4400, but devoid of an inflection point and hollow body. Similar to Table 1 above, the parameters measured to compare the exemplary club head 4400 and the Control Club Head were as follows: ball speed (measured in mph), launch angle (measured in degrees), carry distance (measured in m), and spin rate (measured in rpm).

Table 2: Performance of Club Head 4400 vs. Control Club Head

	Average Ball Speed (mph)	Average Launch Angle (degrees)	Average Spin Rate (rpm)	Average Carry Distance (m)
Club Head 4400	123.8	16.8	6211	163.9 (179.2 yards)
Control 1	123.3	16.1	6746	160.7 (175.7 yards)

[0329] As shown in Table 2, the exemplary club head 4400 having a hollow body and inflection point 4686 produced an average ball speed of 123.8 mph, an average launch angle of 16.8 degrees, an average carry distance of 163.9 m (179.2 yards), and an average spin rate of 6211 rpm, compared to the Control Club Head which produced an average ball speed of 123.3 mph, an average launch angle of 16.1 degrees, an average carry distance of 160.7 m (175.7 yards), and an average spin rate of 6746 rpm. The exemplary club head 4400 experienced a 0.5-1% increase in ball speed compared to the Control Club Head, but due to the hollow body and inflection point 4686 which increased the bending of the strikeface 4412, the exemplary club head 4400 experienced a 4.35% increase in the launch angle and a 7.93% decrease in the spin rate. Because of the 4.35% increase in the launch angle and 7.93% decrease in spin rate, the exemplary club head 4400 experienced an increase of around 2% of the carry distance farther than the Control Club Head. Therefore, this increase in bending of the strikeface 4412 due to the hollow body and inflection 4686 of the exemplary club head 4400 allows for farther carry distances of the ball compared to club head similar in size, devoid of an inflection point.

Example 3: Smaller Volume Hollow Body Irons vs. Hollow Body Crossover

[0330] Referring to Table 3 below, the exemplary club head 3700, and exemplary club head 4400 were compared to exemplary club head 2700. All three exemplary club heads 3700, 4400, and 2700 had similar loft angles and comprised a hollow body, and an inflection point. Exemplary club heads 3700 and 4400 are both significantly smaller in size (volume ranging from 10.65 cm³ (0.65 inch³) to 27.87 cm³ (1.70 inches³)) than the exemplary club head 2700 (volume around 28.68 cm³ (1.75 inches³)). Similar to Table 1 and Table 2 above, the parameters measured for the exemplary club heads 3700, 4400, and 2700 are ball speed (measured in mph), launch angle (measured in degrees), carry distance (measured in m), and spin rate (measured in rpm).

Table 3: Performance of Club Head 3700 and Club Head 400 vs. Club Head 2700

	Average Ball Speed (mph)	Average Launch Angle (degrees)	Average Spin Rate (rpm)	Average Carry Distance (m)
Club Head 3700	138.8	12.2	4322	200.3 (219 yards)
Club Head 4400	138.0	11.4	4135	197.5 (216 yards)
Club Head 2700	139.3	11.8	4312	198.4 (217 yards)

[0331] As shown in Table 3, the exemplary club head 3700 produced an average ball speed of 138.8 mph, an average launch angle of 12.2 degrees, an average spin rate of 4322 rpm, and an average carry distance of 200.3 m (219 yards); the exemplary club head 4400 produced an average ball speed of 138.0 mph, an average launch angle of 11.4 degrees, an average spin rate of 4135 rpm, and an average carry distance of 197.5 m (216 yards); and the exemplary club head 2700 produced an average ball speed of 139.3 mph, an average launch angle of 11.8 degrees, an average spin rate of 4312 rpm, and an average carry distance of 198.4 m (217 yards). The exemplary club head 3700 experienced a 0.92% increase in carry distance over the exemplary club had 2700, while the exemplary club head 4400 experienced a 0.46% decrease in carry distance compared to the exemplary club had 2700. The small percent difference of the carry distance of the ball between the exemplary club heads 3700, 4400, and 2700, were indicative to the bending of the strikeface due to the hollow body and inflection points, regardless of the significantly smaller sizes of the exemplary club head 3700 and exemplary club head 4400. Because of the smaller size and lower inflection point, the exemplary club heads 3700 and 4400 allows a player the benefit of the look and feel of a smaller iron body club head, with the ball performance results (e.g., launch angle, carry distance) of a higher volume sized hollow body club head with a higher inflection point (i.e., exemplary club head 2700).

Example 4: Cavity Back vs. Hollow Body/Inflection Point Golf Club

[0332] Referring to Table 4 below, the exemplary club head 4900 is a hollow bodied iron club head with an inflection point 5186 located roughly 52% below the top rail apex. The club head 4900 was compared to a control club head (hereafter "Control Club Head"). Control Club Head was a cavity back iron club head similar in size to exemplary club head 4900, but devoid of an inflection point and hollow body. The Control Club Head comprised a loft angle roughly 1° lower than the exemplary club head 4900. Similar to Table 1 above, the parameters measured to compare the exemplary club head 4900 and the Control Club Head were as follows: ball speed (measured in mph), launch angle (measured in degrees), carry distance (measured in yards), and spin rate (measured in rpm).

Table 4: Performance of Club Head 4900 vs. Control Club Head

	Average Ball Speed (mph)	Average Launch Angle (degrees)	Average Spin Rate (rpm)	Average Carry Distance (m) (
Club Head 4900	145.1	11.6	3980	209.4 (229 yards)
Control 1	146.1	11.1	4073	207.6 (227 yards)

[0333] As shown in Table 2, the exemplary club head 4900 having a hollow body and inflection point 5186 produced an average ball speed of 145.1 mph, an average launch angle of 11.6 degrees, an average carry distance of 209.4 m (229 yards), and an average spin rate of 3980 rpm, compared to the Control Club Head which produced an average ball speed of 146.1 mph, an average launch angle of 11.1 degrees, an average carry distance of 207.6 m (227 yards), and an average spin rate of 4073 rpm.

[0334] The higher launch angle of the club head 4900 results from its higher loft angle. The lower ball speed can also be expected due to the higher loft angle of the club head 4900. The unexpected result is in the spin rate of the club head 4900 versus the spin rate of the Control Club Head. One of skill in the art would expect the spin rate of the higher-lofted club head (in this example the club head 4900) to be significantly greater than the spin rate of the lower-lofted club head (in this example the Control Club Head). However, the measured spin rates are close to each other, to the extent that in the measured data, the error bars of the spin rates overlap. The spin rates of the club head 4900 and the Control Club Head are not significantly different. Thus, this test shows that the golf club head 4900 exhibits lower spin rates than the Control Club Head for a given loft angle. This lower spin rate reduces the ballooning of the golf ball during flight. Golf balls that are imparted a high spin rate upon impact tend to twist upwards, or balloon, during flight. This dynamic increase in the flight trajectory height of the golf ball can adversely affect the carry distance and result in unpredictable shots. The average carry distance for the exemplary golf club 4900 is roughly the same as the average carry distance of the Control Club Head. The inflection point 5186 of the exemplary club head 4900 along with the hollow body allow the faceplate 4912 to bend in a manner that reduces the spin imparted to the golf ball.

[0335] In addition to the data in Table 4 above, the test revealed an average statistical plot area within which the test shots landed. The average statistical plot area for the exemplary club head 4900 was 6.2% smaller than the average statistical plot area for the Control Club Head. This shows that the exemplary club head 4900 demonstrated higher precision than the Control Club Head. Therefore, the hinging of the faceplate 4912 about the inflection point 5186 does not adversely affect the golfer's ability to control their shots. Rather, the golfer's shot precision is increased.

[0336] Replacement of one or more claimed elements constitutes reconstruction and not repair. Additionally, benefits, other advantages, and solutions to problems have been described with regard to specific embodiments. The benefits, advantages, solutions to problems, and any element or elements that may cause any benefit, advantage, or solution to occur or become more pronounced, however, are not to be construed as critical, required, or essential features or elements of any or all of the claims, unless such benefits, advantages, solutions, or elements are expressly stated in such claims.

[0337] As the rules to golf may change from time to time (e.g., new regulations may be adopted or old rules may be eliminated or modified by golf standard organizations and/or governing bodies such as the United States Golf Association (USGA), the Royal and Ancient Golf Club of St. Andrews (R&A), etc.), golf equipment related to the apparatus, methods, and articles of manufacture described herein may be conforming or non-conforming to the rules of golf at any particular time. Accordingly, golf equipment related to the apparatus, methods, and articles of manufacture described herein may be advertised, offered for sale, and/or sold as conforming or non-conforming golf equipment. The apparatus, methods, and articles of manufacture described herein are not limited in this regard.

[0338] While the above examples may be described in connection with a driver-type golf club, the apparatus, methods, and articles of manufacture described herein may be applicable to other types of golf club such as a fairway wood-type golf club, a hybrid-type golf club, an iron-type golf club, a wedge-type golf club, or a putter-type golf club. Alternatively, the apparatus, methods, and articles of manufacture described herein may be applicable to other type of sports equipment such as a hockey stick, a tennis racket, a fishing pole, a ski pole, etc.

Claims

1. A golf club head (7100) comprising:

a body (7106) having a sole (7122) and a top rail (7124) opposite the sole;

a faceplate (7108) defining a strikeface (7112);

a back wall (7132) opposite the strikeface;

a back cavity (7102) defined within the golf club head between the faceplate, the back wall, the sole, and the top rail;

an indention (7130) formed in the back wall and extending toward the strikeface;

a rear opening (7104) defined within the indention, the rear opening communicating with the back cavity at or proximate an exterior of the golf club head; and

wherein a midplane (7188) divides the strikeface (7112) into an upper region and a lower region by extending-through a geometric center of the strikeface and perpendicular thereto between the top rail and the sole; the golf club head characterized in that 100% of the area of the rear opening is positioned between the midplane and the top rail.

2. The golf club head (7100) of claim 1,
wherein a projected area (7189) of the rear opening (7104) is defined by projecting an area of the rear opening onto the strikeface along a direction parallel to the midplane.

3. The golf club head (7100) of claim 2, wherein 100% of the projected area (7189) is located on the upper region.

4. The golf club head (7100) of claim 1, wherein the back wall (7132) surrounds and defines the indention (7130); and
the back wall extends between the top rail (7124) and the sole (7122).

5. The golf club head (7100) of claim 4, wherein the back wall (7132) is further divided into an upper back wall and a lower back wall;

wherein the upper back wall is adjacent the top rail (7124) and extends downward from the top rail; and

wherein the lower back wall is adjacent the sole (7122) and extends upward from the sole.

6. The golf club head (7100) of claim 5, wherein a rear opening rim (7148) circumscribes the rear opening (7104);

wherein the rear opening rim is divided into an upper rim (7150) and a lower rim (7152);

wherein the upper rim is near the top rail (7124) and follows a contour of the upper back wall; and wherein the lower rim near the sole (7122) and follows a contour of the lower back wall.

7. The golf club head (7100) of claim 6, wherein a badge (7114) closes at least a portion of the indention (7130) from the back cavity (7102), by being positioned within the rear opening rim (7148).

8. The golf club head (7100) of claim 7, wherein:

(1) the badge (7114) is adhered to the upper rim (7150) and lower rim (7152);

(2) wherein the badge covers an upper portion of the rear opening (7104), wherein the upper portion of the rear opening is adjacent the upper rim;

(3) the badge covers a lower portion of the rear opening, wherein the lower portion of the rear opening is adjacent the lower rim; or

(4) the badge is selectively removable.

9. The golf club head (7100) of claim 8, wherein the badge (7114) is made from any one of the following materials: aluminum, titanium, polymer, elastomer, or composite.

10. The golf club head (7100) of claim 1, wherein the faceplate (7108) is made from any one of the following materials: C300 steel, 17-4 stainless steel, 455 steel, 475 steel, 431 steel, maraging steel, titanium, composite, C350 steel, a Ni-Co-Cr steel alloy, a quench and tempered steel alloy, or 565 steel.

11. The golf club head (7100) of claim 1, wherein the body (7106) is made from any one of the following materials: 17-4 stainless steel, 455 steel, 475 steel, 431 steel, maraging steel, titanium, or composite.

12. The golf club head (7100) of claim 1, wherein the strikeface (7112) is coated with a durable finish;
wherein the durable finish can be a Hydropearl 2.0 chrome plate finish or a high polished chrome finish.

13. The golf club head (7100) of claim 7, wherein the back cavity (7102) of the club head can be filled with a vibration damping filler material (7192).

14. The golf club head (7100) of claim 13, wherein the vibration damping filler material (7192) can fill 10% to 80% of a volume of the back cavity (7102), wherein optionally the vibration damping filler material can be any one of the following materials: polyethylene terephthalate, high-density polyethylene, polyvinyl chloride, polycarbonate, polypropylene, hot melt, other thermoplastics, composites, or polymer.

15. The golf club head (7100) of claim 13, wherein the vibration damping filler material (7192) can comprise a specific gravity ranging from 0.05 to 4.

Ansprüche

1. Golfschlägerkopf (7100), umfassend:

einen Körper (7106), der eine Sohle (7122) und eine der Sohle gegenüberliegende obere Schiene (7124) aufweist;

eine Schlagflächenplatte (7108), die eine Schlagfläche (7112) definiert;

eine der Schlagfläche gegenüberliegende Rückwand (7132);

einen Rückseitenhohlraum (7102), der innerhalb des Golfschlägerkopfs zwischen der Schlagflächenplatte, der Rückwand, der Sohle und der oberen Schiene definiert ist;

eine Vertiefung (7130), die in der Rückwand ausgebildet ist und sich in Richtung der Schlagfläche erstreckt;

eine rückseitige Öffnung (7104), die innerhalb der Vertiefung definiert ist, wobei die rückseitige Öffnung an oder nahe einer Außenseite des Golfschlägerkopfs mit dem Rückseitenhohlraum in Verbindung steht; und

wobei eine Mittelebene (7188) die Schlagfläche (7112) in einen oberen Bereich und einen unteren Bereich unterteilt, indem sie sich durch einen geometrischen Mittelpunkt der Schlagfläche und senkrecht dazu zwischen der oberen Schiene und der Sohle erstreckt; wobei der Golfschlägerkopf dadurch gekennzeichnet ist, dass

100 % der Fläche der rückseitigen Öffnung zwischen der Mittelebene und der oberen Schiene positioniert ist.

2. Golfschlägerkopf (7100) nach Anspruch 1,
wobei eine projizierte Fläche (7189) der rückseitigen Öffnung (7104) definiert ist, indem eine Fläche der rückseitigen Öffnung entlang einer zu der Mittelebene parallelen Richtung auf die Schlagfläche projiziert wird.

3. Golfschlägerkopf (7100) nach Anspruch 2, wobei sich 100 % der projizierten Fläche (7189) in dem oberen Bereich befinden.

4. Golfschlägerkopf (7100) nach Anspruch 1, wobei die Rückwand (7132) die Vertiefung (7130) umgibt und definiert; und
sich die Rückwand zwischen der oberen Schiene (7124) und der Sohle (7122) erstreckt.

5. Golfschlägerkopf (7100) nach Anspruch 4, wobei die Rückwand (7132) weiter in eine obere Rückwand und eine untere Rückwand unterteilt ist;

wobei die obere Rückwand an die obere Schiene (7124) angrenzt und sich von der oberen Schiene nach unten erstreckt; und

wobei die untere Rückwand an die Sohle (7122) angrenzt und sich von der Sohle nach oben erstreckt.

6. Golfschlägerkopf (7100) nach Anspruch 5, wobei ein rückseitiger Öffnungsrand (7148) die rückseitige Öffnung (7104) umgibt;

wobei der rückseitige Öffnungsrand in einen oberen Rand (7150) und einen unteren Rand (7152) unterteilt ist;

wobei sich der obere Rand in der Nähe der oberen Schiene (7124) befindet und einer Kontur der oberen Rückwand folgt; und

wobei sich der untere Rand in der Nähe der Sohle (7122) befindet und einer Kontur der unteren Rückwand folgt.

7. Golfschlägerkopf (7100) nach Anspruch 6, wobei ein Badge (7114) zumindest einen Teil der Vertiefung (7130) von dem Rückseitenhohlraum (7102) verschließt, indem es innerhalb des rückseitigen Öffnungsrandes (7148) positioniert ist.

8. Golfschlägerkopf (7100) nach Anspruch 7, wobei:

(1) das Badge (7114) an dem oberen Rand (7150) und an dem unteren Rand (7152) anhaftet;

(2) wobei das Badge einen oberen Teil der rückseitigen Öffnung (7104) abdeckt, wobei der obere Teil der rückseitigen Öffnung an den oberen Rand angrenzt;

(3) das Badge einen unteren Teil der rückseitigen Öffnung abdeckt, wobei der untere Teil der rückseitigen Öffnung an den unteren Rand angrenzt; oder

(4) das Badge selektiv entfernbar ist.

9. Golfschlägerkopf (7100) nach Anspruch 8, wobei das Badge (7114) aus einem der folgenden Materialien hergestellt ist: Aluminium, Titan, Polymer, Elastomer oder Verbundwerkstoff.

10. Golfschlägerkopf (7100) nach Anspruch 1, wobei die Schlagflächenplatte (7108) aus einem der folgenden Materialien hergestellt ist: C300-Stahl, 17-4-Edelstahl, 455-Stahl, 475-Stahl, 431-Stahl, Maraging-Stahl, Titan, Verbundwerkstoff, C350-Stahl, eine Ni-Co-Cr-Stahllegierung, eine vergütete Stahllegierung oder 565-Stahl.

11. Golfschlägerkopf (7100) nach Anspruch 1, wobei der Körper (7106) aus einem der folgenden Materialien hergestellt ist: 17-4-Edelstahl, 455-Stahl, 475-Stahl, 431-Stahl, Maraging-Stahl, Titan oder Verbundwerkstoff.

12. Golfschlägerkopf (7100) nach Anspruch 1, wobei die Schlagfläche (7112) mit einem beständigen Finish beschichtet ist;
wobei das beständige Finish ein Hydropearl-2.0-Chromplatten-Finish oder ein hochglanzpoliertes Chrom-Finish sein kann.

13. Golfschlägerkopf (7100) nach Anspruch 7, wobei der Rückseitenhohlraum (7102) des Schlägerkopfs mit einem schwingungsdämpfenden Füllmaterial (7192) gefüllt sein kann.

14. Golfschlägerkopf (7100) nach Anspruch 13, wobei das schwingungsdämpfende Füllmaterial (7192) 10 % bis 80 % eines Volumens des Rückseitenhohlraums (7102) ausfüllen kann, wobei das schwingungsdämpfende Füllmaterial optional eines der folgenden Materialien sein kann: Polyethylenterephthalat, Polyethylen hoher Dichte, Polyvinylchlorid, Polycarbonat, Polypropylen, Schmelzklebstoff, andere Thermoplaste, Verbundwerkstoffe oder Polymer.

15. Golfschlägerkopf (7100) nach Anspruch 13, wobei das schwingungsdämpfende Füllmaterial (7192) ein spezifisches Gewicht in dem Bereich von 0,05 bis 4 umfassen kann.

Revendications

1. Tête (7100) de club de golf comprenant :

un corps (7106) présentant une semelle (7122) et un rail supérieur (7124) en regard de la semelle ;

une plaque frontale (7108) définissant une face de frappe (7112) ;

une paroi de fond (7132) en regard de la face de frappe ;

une cavité de fond (7102) définie dans la tête de club de golf entre la plaque frontale, la paroi de fond, la semelle et le rail supérieur ;

une encoche (7130) formée dans la paroi de fond et s'étendant vers la face de frappe ;

une ouverture arrière (7104) définie dans l'encoche, l'ouverture arrière communiquant avec la cavité de fond au niveau d'un extérieur de la tête de club de golf ou à proximité de celui-ci ; et

dans laquelle un plan médian (7188) divise la face de frappe (7112) en une région supérieure et une région inférieure en s'étendant par un centre géométrique de la face de frappe et perpendiculairement à celle-ci entre le rail supérieur et la semelle ; la tête de club de golf étant caractérisée en ce que

100 % de la superficie de l'ouverture arrière est positionnée entre le plan médian et le rail supérieur.

2. Tête (7100) de club de golf selon la revendication 1,
dans laquelle une superficie projetée (7189) de l'ouverture arrière (7104) est définie par la projection d'une superficie de l'ouverture arrière sur la face de frappe le long d'une direction parallèle au plan médian.

3. Tête (7100) de club de golf selon la revendication 2, dans laquelle 100 % de la superficie projetée (7189) est située sur la région supérieure.

4. Tête (7100) de club de golf selon la revendication 1, dans laquelle la paroi de fond (7132) entoure et définit l'encoche (7130) ; et
la paroi de fond s'étend entre le rail supérieur (7124) et la semelle (7122).

5. Tête (7100) de club de golf selon la revendication 4, dans laquelle la paroi de fond (7132) est en outre divisée en une paroi de fond supérieure et une paroi de fond inférieure ;

dans laquelle la paroi de fond supérieure est adjacente au rail supérieur (7124) et s'étend vers le bas depuis le rail supérieur ;
et

dans laquelle la paroi de fond inférieure est adjacente à la semelle (7122) et s'étend vers le haut depuis la semelle.

6. Tête (7100) de club de golf selon la revendication 5, dans laquelle un rebord (7148) d'ouverture arrière circonscrit l'ouverture arrière (7104) ;

dans laquelle le rebord d'ouverture arrière est divisé en un rebord supérieur (7150) et un rebord inférieur (7152) ;

dans laquelle le rebord supérieur est proche du rail supérieur (7124) et suit un contour de la paroi de fond supérieure ; et

dans laquelle le rebord inférieur est proche de la semelle (7122) et suit un contour de la paroi de fond inférieure.

7. Tête (7100) de club de golf selon la revendication 6, dans laquelle un badge (7114) ferme au moins une partie de l'encoche (7130) par rapport à la cavité de fond (7102), en étant positionné dans le rebord (7148) d'ouverture arrière.

8. Tête (7100) de club de golf selon la revendication 7, dans laquelle :

(1) le badge (7114) adhère au rebord supérieur (7150) et au rebord inférieur (7152) ;

(2) dans laquelle le badge recouvre une partie supérieure de l'ouverture arrière (7104), dans laquelle la partie supérieure de l'ouverture arrière est adjacente au rebord supérieur ;

(3) le badge recouvre une partie inférieure de l'ouverture arrière, dans laquelle la partie inférieure de l'ouverture arrière est adjacente au rebord inférieur ; ou

(4) le badge est sélectivement amovible.

9. Tête (7100) de club de golf selon la revendication 8, dans laquelle le badge (7114) est fabriqué à partir de l'un quelconque des matériaux suivants : aluminium, titane, polymère, élastomère ou composite.

10. Tête (7100) de club de golf selon la revendication 1, dans laquelle la plaque frontale (7108) est fabriquée à partir de l'un quelconque des matériaux suivants : acier C300, acier inoxydable 17-4, acier 455, acier 475, acier 431, acier maraging, titane, composite, acier C350, un alliage d'acier Ni-Co-Cr, un alliage d'acier trempé et revenu ou acier 565.

11. Tête (7100) de club de golf selon la revendication 1, dans laquelle le corps (7106) est fabriqué à partir de l'un quelconque des matériaux suivants : acier inoxydable 17-4, acier 455, acier 475, acier 431, acier maraging, titane ou composite.

12. Tête (7100) de club de golf selon la revendication 1, dans laquelle la face de frappe (7112) est revêtue d'une finition durable ;
dans laquelle la finition durable peut être une finition plaquée de chrome Hydropearl 2.0 ou une finition chromée hautement polie

13. Tête (7100) de club de golf selon la revendication 7, dans laquelle la cavité de fond (7102) de la tête de club peut être remplie d'un matériau de charge à amortissement de vibrations (7192).

14. Tête (7100) de club de golf selon la revendication 13, dans laquelle le matériau de charge à amortissement de vibrations (7192) peut remplir de 10 % à 80 % d'un volume de la cavité de fond (7102), dans laquelle facultativement le matériau de charge à amortissement de vibrations peut être l'un quelconque des matériaux suivants : polyéthylène téréphtalate, polyéthylène haute densité, polychlorure de vinyle, polycarbonate, polypropylène, adhésif thermofusible, autres thermoplastiques, composites ou polymère.

15. Tête (7100) de club de golf selon la revendication 13, dans laquelle le matériau de charge à amortissement de vibrations (7192) peut comprendre une gravité spécifique comprise dans la plage de 0,05 à 4.

Drawing