CROSS REFERENCE TO RELATED APPLICATIONS
BACKGROUND OF THE INVENTION
Field of the Invention
[0002] The present invention relates to an iron golf club head and an iron golf club.
Description of the Background Art
[0003] Japanese Patent No. 6706950 discloses an iron golf club head that can achieve both high rebound property and
high durability. The iron golf club head disclosed in the above-identified patent
publication includes a thick portion, a thin portion, and a tapered portion. The thick
portion is located almost centrally in the direction from the toe side toward the
heel side. The thin portion is located around the thick portion. The tapered portion
is located between the thick portion and the thin portion.
[0004] The iron golf club heads are required to have an angle adjustment capability for
adjusting the loft angle and the lie angle. The patent publication does not disclose
the angle adjustment capability.
SUMMARY OF THE INVENTION
[0005] The present invention has been made in view of the problems as described above, and
an object of the present invention is to provide an iron golf club head and an iron
golf club that can achieve both high rebound property and high durability and improve
the angle adjustment capability.
[0006] An iron golf club head of the present invention includes a main body and a hosel.
The main body includes a toe, a heel, a face, and a back face. The hosel is connected
to the heel of the main body. The face and the hosel are made from the same material.
The face includes a thin portion and a thick portion having a larger thickness than
the thin portion in a face-to-back direction from the face toward the back face. The
thin portion has a larger area than the thick portion. The thick portion is located
centrally of the back face in a toe-to-heel direction from the toe toward the heel,
surrounded by the thin portion, and protrudes from the thin portion in the face-to-back
direction. The face has a hardness of HV510 or more and HV600 or less. The hosel has
a hardness of HV300 or less.
[0007] With the iron golf club head and the iron golf club of the present invention, both
high rebound property and high durability can be achieved and the angle adjustment
capability can be improved.
[0008] The foregoing and other objects, features, aspects and advantages of the present
invention will become more apparent from the following detailed description of the
present invention when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009]
Fig. 1 is a front view schematically showing a configuration of an iron golf club
head according to Embodiment 1.
Fig. 2 is a rear view schematically showing the configuration of the iron golf club
head according to Embodiment 1.
Fig. 3 is a right side view schematically showing the configuration of the iron golf
club head according to Embodiment 1.
Fig. 4 is a cross-sectional view along a line IV-IV in Fig. 3.
Fig. 5 is a cross-sectional view along a line V-V in Fig. 2.
Fig. 6 is a cross-sectional view along a line VI-VI in Fig. 2.
Fig. 7 is a rear view schematically showing a configuration of an iron golf club according
to Embodiment 1.
Fig. 8 is a rear view schematically showing a configuration of an iron golf club head
according to Embodiment 2.
Fig. 9 is a front view schematically showing a configuration of an iron golf club
head according to Embodiment 3.
Fig. 10 is a rear view schematically showing the configuration of the iron golf club
head according to Embodiment 3.
Fig. 11 is a right side view schematically showing the configuration of the iron golf
club head according to Embodiment 3.
Fig. 12 is a cross-sectional view along a line XII-XII in Fig. 11.
Fig. 13 is a cross-sectional view along a line XIII-XIII in Fig. 10.
Fig. 14 is a cross-sectional view along a line XIV-XIV in Fig. 10.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0010] Embodiments of the present invention are hereinafter described based on the drawings.
In the following drawings, the same or corresponding parts are denoted by the same
reference characters, and a description thereof is not herein repeated, unless otherwise
specified.
(Embodiment 1)
[0011] Referring to Figs. 1 to 6, an iron golf club head 100 according to Embodiment 1 is
described.
[0012] As shown in Figs. 1 and 2, iron golf club head 100 according to Embodiment 1 includes
a main body 10 and a hosel 20.
[0013] Main body 10 includes a toe 10a, a heel 10b, a top 10c, a sole 10d, a face 11, score
lines (grooves) 12, a back face 13, a thin portion 14, a thick portion 15, and a cavity
wall 16.
[0014] Face 11 and hosel 20 are made from the same material. The material for face 11 and
hosel 20 is chromium molybdenum steel or nickel chromium molybdenum steel. The material
for face 11 and hosel 20 is preferably nickel chromium molybdenum steel. While main
body 10, except for face 11, of iron golf club head 100 according to Embodiment 1
is made from the same material as face 11, it may be made from a different material
from face 11.
[0015] Face 11 and hosel 20 may be formed by casting, or formed by forging. For example,
iron golf club head 100 according to Embodiment 1 has a one-piece cast structure.
[0016] Face 11 is a ball striking surface. Face 11 is surrounded by toe 10a, heel 10b, top
10c, and sole 10d. Toe 10a is a part connecting top 10c to sole 10d on the side located
away from hosel 20. Heel 10b is a part extending from the lower end of hosel 20 to
sole 10d. Top 10c is a part forming an upper edge of main body 10 extending from hosel
20 to toe 10a. Sole 10d is a part forming a lower edge (bottom) of main body 10.
[0017] Face 11 is provided with a plurality of score lines (grooves) 12. Each of a plurality
of score lines (grooves) 12 extends linearly in the toe-to-heel direction from toe
10a toward heel 10b (direction laterally across face 11). A plurality of score lines
(grooves) 12 are arranged at substantially regular intervals in the top-to-sole direction
from top 10c toward sole 10d (direction vertically across face 11).
[0018] Back face 13 is located rearward of face 11. Back face 13 is located opposite to
face 11. Back face 13 is provided to both thin portion 14 and thick portion 15.
[0019] As shown in Figs. 2 and 3, cavity wall 16 surrounds the perimeter of back face 13.
Cavity wall 16 is formed to extend along toe 10a, heel 10b, top 10c, and sole 10d.
Cavity wall 16 defines a cavity 17. Cavity 17 is surrounded by cavity wall 16.
[0020] As shown in Fig. 4, thin portion 14 has a larger area than thick portion 15. In Fig.
4, the region hatched by bold lines represents thin portion 14. Thin portion 14 has
a larger area than thick portion 15 within the plane of back face 13. Thin portion
14 may have an area of 80% or more of the area of back face 13 as seen in plan view.
[0021] As shown in Figs. 5 and 6, thin portion 14 has a smaller thickness than thick portion
15 in the face-to-back direction from face 11 toward back face 13. Thin portion 14
has a smaller thickness than thick portion 15 in the face-to-back direction.
[0022] In the face-to-back direction, the thickness of thin portion 14 is 1.6 mm or more
and 1.8 mm or less. In the case of thin portion 14 having a thickness of less than
1.5 mm, the upper limit of the coefficient of restitution rule of the R&A (Royal and
Ancient Golf Club of St Andrews) may be exceeded. In the case of thin portion 14 having
a thickness of 1.9 mm, a durability test is passed even if the hardness of face 11
is less than HV510, which, however, is accompanied by deterioration of the rebound
property. Further, the weight of the face increases. Accordingly, the thickness of
thin portion 14 has been set to 1.6 mm or more and 1.8 mm or less. The thickness of
thin portion 14 is 1.7 mm, for example. The thickness of thin portion 14 may be substantially
uniform. The thickness of thin portion 14 may also be uniform.
[0023] Thick portion 15 has a larger thickness than thin portion 14 in the face-to-back
direction from face 11 toward back face 13. Thick portion 15 is larger in the thickness
in the face-to-back direction than thin portion 14. The thickness of thick portion
15 is 2.0 mm, for example. This thickness of thick portion 15 is the maximum thickness
of thick portion 15.
[0024] As shown in Fig. 4, thick portion 15 is located centrally of back face 13, in the
toe-to-heel direction from toe 10a toward heel 10b. Thick portion 15 is located to
overlap the center of back face 13, in the toe-to-heel direction. Thick portion 15
is surrounded by thin portion 14. Thick portion 15, except for its portion facing
sole 10d, is surrounded continuously by thin portion 14. As seen in plan view, thick
portion 15 is formed substantially in the shape of an incomplete circle, i.e., a circular
shape except for the portion facing sole 10d.
[0025] As shown in Figs. 5 and 6, thick portion 15 protrudes from thin portion 14 in the
face-to-back direction. On back face 13, thick portion 15 protrudes from thin portion
14 in the face-to-back direction. Thick portion 15 protrudes toward cavity 17 in the
face-to-back direction.
[0026] As shown in Figs. 4 and 5, cavity wall 16 includes a sole-side wall 16s. Sole-side
wall 16s is located on the sole 10d side.
[0027] Thick portion 15 becomes narrower toward sole-side wall 16s. The width, in the toe-to-heel
direction, of thick portion 15 decreases toward sole-side wall 16s. Thick portion
15 is contiguous to sole-side wall 16s. Thin portion 14 is located between thick portion
15 and cavity wall 16 except for sole-side wall 16s.
[0028] Sole-side wall 16s includes a toe-side portion 16a, a center portion 16b, and a heel-side
portion 16c that are arranged in the toe-to-heel direction. Center portion 16b is
located between toe-side portion 16a and heel-side portion 16c in the toe-to-heel
direction. Thick portion 15 is contiguous to center portion 16b. Center portion 16b
has a larger thickness than toe-side portion 16a and heel-side portion 16c. The thickness
of center portion 16b is 1.9 mm, for example. The thickness of toe-side portion 16a
is 1.5 mm, for example. The thickness of heel-side portion 16c is 1.5 mm, for example.
[0029] As shown in Figs. 1 and 2, a sweet spot of face 11 is located to overlap thick portion
15 in the face-to-back direction. The score-line center of face 11 is located to overlap
thick portion 15 in the face-to-back direction.
[0030] Face 11 has a hardness of HV510 or more and HV600 or less. Namely, the hardness of
face 11 is a Vickers hardness (HV) of 510 or more and a Vickers hardness (HV) of 600
or less. At and around the score-line center of face 11, face 11 has a hardness of
HV510 or more and HV600 or less. In the case of face 11 having a hardness of less
than HV510, face 11 subjected to a durability test based on ball hitting was identified
as having cracks in face 11. The reason for the cracks was considered as the insufficient
hardness of face 11. In the case of face 11 having a hardness of more than HV600,
face 11 subjected to a durability test based on ball hitting was identified as having
cracks in face 11. The reason for the cracks was considered as the toughness of face
11 that becomes lower as its hardness increases. Accordingly, the hardness of face
11 has been set to HV510 or more and HV600 or less. The hardness of face 11 herein
refers to the hardness at and around the score-line center of face 11. The Vickers
hardness is a value obtained by measuring the hardness of a site located at a distance
of 1 mm from the face surface.
[0031] Hosel 20 is connected to heel 10b of main body 10. Hosel 20 includes a region that
is bent for adjusting the lie angle and the loft angle. Hosel 20 has a hardness of
HV300 or less. Specifically, the hardness of hosel 20 is a Vickers hardness (HV) of
300 or less. In the case of hosel 20 having a hardness of HV300 or less, there is
no inconvenience for a human to bend the hosel. Specifically, in the case of hosel
20 having a hardness of HV300 or less, a human operator can bend the hosel by a lie
angle of 1 to 2 degrees for adjusting the angle. In the case of hosel 20 having a
hardness of HV250 or less, the workability for adjusting the angle by a human operator
is improved. In the case of hosel 20 having a hardness of more than HV300, it is difficult
for a human to bend the hosel. Specifically, in the case of hosel 20 having a hardness
of HV400, it is difficult for a human operator to bend the hosel by a lie angle of
one degree for adjusting the angle. Accordingly, the hardness of hosel 20 has been
set to HV300 or less. The hardness of hosel 20 herein refers to the hardness at a
site located at distance of approximately 30 mm from the end of the hosel. The Vickers
hardness is a value obtained by measuring the hardness at a site located at a distance
of 2 mm away from the surface of hosel 20.
[0032] Referring to Fig. 7, an iron golf club 200 according to Embodiment 1 is described.
[0033] As shown in Fig. 7, iron golf club 200 according to Embodiment 1 includes iron golf
club head 100 according to Embodiment 1, a shaft 201, and a grip 202.
[0034] Shaft 201 has one end and the other end. Iron golf club head 100 is attached to the
one end of shaft 201. Shaft 201 is attached to hosel 20. The one end of shaft 201
is inserted in hosel 20. Grip 202 is attached to the other end of shaft 201. The other
end of shaft 201 is inserted in grip 202.
[0035] Next, functions and advantageous effects of Embodiment 1 are described.
[0036] Regarding iron golf club head 100 according to Embodiment 1, the hardness of face
11 is HV510 or more and HV600 or less. Thus, face 11 can be made hard to suppress
cracks of face 11 and improve the durability. Face 11 can therefore be designed to
be thin, to thereby achieve both high rebound property and high durability. The hardness
of hosel 20 is HV300 or less. Thus, the angle adjustment capability for adjusting
the lie angle and the loft angle by deforming hosel 20 can be improved. Accordingly,
both high rebound property and high durability can be achieved and the angle adjustment
capability can also be improved.
[0037] Main body 10 includes thin portion 14 and thick portion 15. Thus, main body 10 has
a partially-thick structure. Thin portion 14 has a larger area than thick portion
15. Thus, both high rebound property and high durability can be achieved with no or
minimum increase of the mass of main body 10, as compared with main body 10 having
no thin portion 14.
[0038] Thick portion 15 is located centrally of back face 13 in the toe-to-heel direction,
and surrounded by thin portion 14. Thus, the difference in the total distance between
the case where a ball is shot off-center and the case where the ball is shot at the
sweet spot can be reduced, while the rigidity of the center of face 11 is improved.
[0039] Regarding iron golf club head 100 according to Embodiment 1, thin portion 14 has
a thickness, in the face-to-back direction, of 1.6 mm or more and 1.8 mm or less.
Thus, thin portion 14 can be made thin. It is therefore possible for thin portion
14 to deform easily when hit by a ball. Accordingly, high rebound property can be
improved.
[0040] Regarding iron golf club head 100 according to Embodiment 1, thick portion 15 become
narrower toward sole-side wall 16s and is contiguous to sole-side wall 16s. Thus,
the area of thin portion 14 can be made larger, as compared with the case where thick
portion 15 is not narrowed. Therefore, thin portion 14 can be deformed when hit by
a ball, to improve the coefficient of restitution (COR). The coefficient of restitution
(COR) of the toe side and the heel side can also be improved. Accordingly, high rebound
property can be improved as well for the off-center shot where a ball is hit at the
toe side or the heel side.
[0041] Regarding iron golf club head 100 according to Embodiment 1, center portion 16b has
a larger thickness than toe-side portion 16a and heel-side portion 16c. Thus, toe-side
portion 16a and heel-side portion 16c can be deformed more easily relative to center
portion 16b. It is therefore possible to improve the coefficient of restitution (COR)
of the toe side and the heel side. Accordingly, high rebound property can be improved
as well for the off-center shot where a ball is hit at the toe side or the heel side.
[0042] Regarding iron golf club head 100 according to Embodiment 1, the material for main
body 10 and hosel 20 is nickel chromium molybdenum steel. Thus, face 11 of main body
10 can be made harder to improve the durability, and face 11 can be designed to be
thinner to improve high rebound property.
[0043] Iron golf club 200 according to Embodiment 1 includes iron golf club head 100 according
to Embodiment 1. Thus, iron golf club 200 can be obtained that enables both high rebound
property and high durability to be achieved, and the angle adjustment capability to
be improved.
(Embodiment 2)
[0044] An iron golf club head 100 according to Embodiment 2 has the same configuration and
the same functions and advantageous effects as iron golf club head 100 according to
Embodiment 1, unless otherwise specified.
[0045] Referring to Fig. 8, iron golf club head 100 according to Embodiment 2 is described.
As shown in Fig. 8, iron golf club head 100 according to Embodiment 2 differs from
Embodiment 1, in terms of the configuration of thick portion 15.
[0046] In iron golf club head 100 according to Embodiment 2, thick portion 15 extends straight
toward sole-side wall 16s. That is, thick portion 15 is not narrowed toward sole-side
wall 16s.
[0047] Iron golf club head 100 according to Embodiment 2 also enables both high rebound
property and high durability to be achieved, and the angle adjustment property to
be improved.
(Embodiment 3)
[0048] An iron golf club head 100 according to Embodiment 3 has the same configuration and
the same functions and advantageous effects as iron golf club head 100 according to
Embodiment 1, unless otherwise specified.
[0049] Next, referring to Figs. 9 to 14, iron golf club head 100 according to Embodiment
3 is described. As shown in Figs. 9 to 14, iron golf club head 100 according to Embodiment
3 differs from Embodiment 1 in terms of the configuration of thick portion 15. In
Fig. 12, the region hatched by bold lines represents thin portion 14.
[0050] As shown in Figs. 9 to 12, in iron golf club head 100 according to Embodiment 3,
thick portion 15 includes a first portion 151, a second portion 152, and a third portion
153. First portion 151 is located between second portion 152 and third portion 153
in the toe-to heel direction. As seen in plan view, first portion 151 is formed substantially
in the shape of an incomplete circle, i.e., a circular shape except for the portion
facing sole 10d.
[0051] Second portion 152 protrudes from first portion 151 toward toe 10a. As seen in plan
view, second portion 152 is formed substantially in an oval shape, except for the
portion connected to first portion 151. Second portion 152, except for the portion
connected to first portion 151, is surrounded continuously by thin portion 14. Second
portion 152 is located centrally of back face 13 in the top-to-sole direction. In
the top-to-sole direction, thin portion 14 is located on the top side and the sole
side of second portion 152. Second portion 152 is located to overlap the height position
of a sweet spot in the top-to-sole direction.
[0052] Third portion 153 protrudes from first portion 151 toward heel 10b. As seen in plan
view, third portion 153 is formed substantially in an oval shape, except for the portion
connected to first portion 151. Third portion 153, except for the portion connected
to first portion 151, is surrounded continuously by thin portion 14. Third portion
153 is located centrally of back face 13 in the top-to-sole direction. In the top-to-sole
direction, thin portion 14 is located on the top side and the sole side of third portion
153. Third portion 153 is located to overlap the height position of the sweet spot
in the top-to-sole direction.
[0053] As shown in Figs. 13 and 14, second portion 152 has a smaller thickness than first
portion 151 in the face-to-back direction. The thickness of second portion 152 in
the face-to-back direction is 1.85 mm, for example. This thickness of second portion
152 is the maximum thickness of second portion 152.
[0054] Third portion 153 has a smaller thickness than second portion 152 in the face-to-back
direction. The thickness, in the face-to-back direction, of third portion 153 is 1.8
mm, for example. This thickness of third portion 153 is the maximum thickness of third
portion 153.
[0055] In iron golf club head 100 according to Embodiment 3, thick portion 15 includes first
portion 151, second portion 152 protruding from first portion 151 toward toe 10a,
and third portion 153 protruding from first portion 151 toward heel 10b. Thus, the
difference in the total distance between the case where a ball is hit at the toe side
or the heel side, i.e., off-center shot, and the case where the ball is hit at the
sweet spot, can be reduced, while the rigidity of the center of face 11 is improved.
[0056] Second portion 152 has a smaller thickness than first portion 151 in the face-to-back
direction, and third portion 153 has a smaller thickness than second portion 152 in
the face-to-back direction. The coefficient of restitution (COR) of the toe side and
the heel side can be improved. Thus, high rebound property can also be improved for
the off-center shot where a ball is hit on the toe side or the heel side, while the
rigidity of the center of face 11 is improved.
[0057] Although the present invention has been described and illustrated in detail, it is
clearly understood that the same is by way of illustration and example only and is
not to be taken by way of limitation, the scope of the present invention being interpreted
by the terms of the appended claims.
1. An iron golf club head (100) comprising:
a main body (10) including a toe (10a), a heel (10b), a face (11), and a back face
(13); and
a hosel (20) connected to the heel (10b) of the main body (10), wherein
the face (11) and the hosel (20) are made from the same material,
the face (11) includes a thin portion (14) and a thick portion (15) having a larger
thickness than the thin portion (14) in a face-to-back direction from the face (11)
toward the back face (13),
the thin portion (14) has a larger area than the thick portion (15),
the thick portion (15) is located centrally of the back face (13) in a toe-to-heel
direction from the toe (10a) toward the heel (10b), surrounded by the thin portion
(14), and protrudes from the thin portion (14) in the face-to-back direction,
the face (11) has a hardness of HV510 or more and HV600 or less, and
the hosel (20) has a hardness of HV300 or less.
2. The iron golf club head (100) according to claim 1, wherein the thin portion (14)
has a thickness of 1.6 mm or more and 1.8 mm or less in the face-to-back direction.
3. The iron golf club head (100) according to claim 1, wherein
the main body (10) includes a cavity wall (16) surrounding a perimeter of the back
face (13),
the cavity wall (16) includes a sole-side wall (16s), and
the thick portion (15) becomes narrower toward the sole-side wall (16s) and is contiguous
to the sole-side wall (16s).
4. The iron golf club head (100) according to claim 3, wherein
the sole-side wall (16s) includes a toe-side portion (16a), a center portion (16b),
and a heel-side portion (16c) that are arranged in the toe-to-heel direction, and
the center portion (16b) has a larger thickness than the toe-side portion (16a) and
the heel-side portion (16c).
5. The iron golf club head (100) according to claim 4, wherein
the thick portion (15) includes a first portion (151), a second portion (152) protruding
from the first portion (151) toward the toe (10a), and a third portion (153) protruding
from the first portion (151) toward the heel (10b),
the second portion (152) has a smaller thickness than the first portion (151) in the
face-to-back direction, and
the third portion (153) has a smaller thickness than the second portion (152) in the
face-to-back direction.
6. An iron golf club (200) comprising:
the iron golf club head (100) according to any one of claims 1 to 5; and
a shaft (201) attached to the hosel (20).