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(11) | EP 0 691 142 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Golf club head |
| (57) A golf club head (10) has a body with a front wall (12), rear wall, upper wall (14),
lower wall, a heel portion (16) of solid material, a toe (18) and an internal hollow
cavity (22). The heel portion (16) has a bore (24) extending inwardly from the upper
wall (14) into the solid material of the heel portion (16) at a selected angle. A
separate hosel tube (30) is secured in the bore (24). |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Continuation-In-Part of co-pending Application Serial No. 08/159,738 filed November 30, 1993.
BACKGROUND OF THE INVENTION
[0002] The present invention relates generally to golf clubs and is particularly concerned with the attachment of the golf club shaft to a club head.
[0003] Golf club shafts are secured to club heads in a number of different ways. In some cases, the club head is formed with an integral hollow neck or hosel which projects upwardly from the heel at a desired angle and into which the shaft extends. A separate shaft mounting tube may be secured in the hollow neck for receiving the end of the golf club shaft, as described in U.S. Patent No. 4,438,931 of Motomiya. In the case of metal wood type golf clubs which are made by investment casting of stainless steel, integral hosel necks add weight and are prone to cause breakage of the relatively brittle graphite or composite shaft. Such clubs are also not readily adjustable in manufacture to produce the desired orientation of the shaft relative o the head.
SUMMARY OF THE INVENTION
[0005] According to the present invention, a golf club head is provided which comprises a body having a front face, rear wall, upper wall, lower wall, a heel portion of solid material and a toe portion, and an internal hollow cavity, the heel portion having a bore extending inwardly from the upper wall at a predetermined angle in the solid material of the heel portion, and a separate hosel tube secured in the bore for receiving the end of a golf club shaft. Preferably, the bore terminates in the solid material of the heel portion short of the cavity.
[0006] Thus, the hosel tube or neck of the club head is not formed integrally with the club head but is formed separately and drops into the bore formed in the heel portion of the club head. Preferably, the club head and hosel tube are formed of the same or similar material, preferably aluminum or aluminum alloy or similar lightweight metal of sufficient strength for use in golf clubs. The hosel tube is preferably a straight, cylindrical tube having constant inner and outer diameters. Because the tube neck extends straight into the heel of the club with no taper, alignment of the club head and face by the player when striking the ball is easier. The blind bore in the heel portion is cylindrical and of diameter substantially matching the outer diameter of the hosel tube.
[0007] The inner surface of the bore and the portion of the outer surface of the hosel tube which engages in the bore may be roughened or provided with surface formations or knurling for improved adhesion of the hosel tube in the bore. The hosel tube may be secured in the bore by bonding, adhesive or the like. In one embodiment, the bore may have circular or helical grooves while the bore-engaging portion of the tube may have linear ribs or knurls, so that a mechanical bond is provided. The ribs also act to center the tube in the bore and provide an even glue line around the tube or neck, and adhesive will flow into the depressions so that more adhesive is held between the surfaces for a stronger bond. The bore terminates short of both the lower wall and internal cavity of the club head.
[0008] The use of a blind bore in the solid material of the heel portion of the head together with a separate, relatively thin hosel tube which simply drops into the bore will reduce weight in the hosel region, providing extra weight which may be distributed about the club head for improved performance. It also provides a stronger connection between the shaft and club head since the hosel tube is embedded in solid material. The shaft angle can be adjusted easily in manufacture by changing the angle of the bore.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The present invention will be better understood from the following detailed description of a preferred embodiment of the invention, taken in conjunction with the accompanying drawings, in which like reference numerals refer to like parts, and in which:
Figure 1 is a perspective view of a typical golf club head incorporating the novel hosel structure according to a preferred embodiment of the present invention;
Figure 2 is a top plan view of the club head;
Figure 3 is a sectional view taken on line 3-3 of Figure 2; and
Figure 4 is a side elevation view of the hosel tube, showing the grooves.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0010] The drawings illustrate a golf club head 10 of the metal wood type according to a preferred embodiment of the present invention. The head 10 has a front, ball striking face 12, an upper wall or crown 14, a heel portion 16, a toe 18, and a sole plate 20. The sole plate 20 is preferably formed separately from the remainder of the head and secured in place by bonding, welding, screw fasteners or the like, although the head may be formed in one piece.
[0011] Head 10 has an internal cavity 22, and the heel portion is of relatively thick, solid material, as best illustrated in Figure 3. A blind bore 24 extends from upper wall 14 into the solid material of the heel portion 16 and terminates at inner end 26 which is short of the inner cavity 22 and the sole plate 20. Preferably, bore 24 terminates at least ⅛ inch above the sole plate. The bore is cylindrical and has screw threads 28 or other surface roughening formations or grooves formed on its cylindrical surface, as illustrated in Figure 3.
[0012] A separate tube neck or cylindrical hosel 30 has one end portion 32 inserted into the blind bore 24 and suitably secured in the bore by adhesive or the like so that part of the tube neck projects upwardly at an angle from the upper wall of the head, as illustrated in Figures 1 and 2. As best illustrated in Figure 4, the tube neck or hosel 30 is a straight cylindrical tube having a pair of annular grooves 33 adjacent its upper end, and a series of spaced vertical ribs or knurls 34 in the lower end portion 32 of the tube which is inserted into the bore 24. The opposing roughened or knurled surfaces of the tube and bore interengage to provide a strong mechanical bond. The knurled surface of the tube or the grooved bore surface is preferably coated with a suitable adhesive prior to insertion of the tube into the bore, so that the hosel tube is firmly bonded in position to provide a strong joint. The grooved, roughened surfaces of the tube and bore provide additional surface area for adhesive and thus a stronger adhesive bond between the parts. The end of a conventional golf club shaft 36 is then secured in the hosel by adhesive or the like, and will project upwardly at the same angle as bore 24. Different heads may be provided with different bore angles to provide clubs with different lie angle, face angle and face progression.
[0013] In a preferred embodiment of the invention, the adhesive used to bond the tube neck in the blind bore 24, and the golf club shaft 36 in neck 30, is an epoxy which is non-brittle, and less liable to fracture, for example Epoweld Type 132.30 made by Hardeman Manufacturing Co., or other equivalent epoxies. This will act as a shock absorber, tending to damp vibrations and reducing the risk of breakage or shearing of the shaft.
[0014] The club head and hosel or tube neck 30 are preferably both of relatively light weight metal such as aluminum or aluminum alloy, and in a preferred embodiment of the invention they are of 6061 T6 aluminum alloy or 7075 T6 aluminum alloy. The head may be of 7075 T6 aluminum alloy, which is stronger, while the hosel or tube neck is of 6061 T6 aluminum alloy. The club head may be manufactured by machining or milling, as described in co-pending Application Serial No. 08/159,738 referred to above, the contents of which are incorporated herein by reference.
[0015] The use of an aluminum alloy tube "drop-in" neck for receiving the end of the shaft reduces weight in the hosel region, both due to the drop-in design and due to the lighter weight material, which is approximately ¹/₃ of the weight of stainless steel as conventionally used in metal woods. This extra weight can be distributed about the body of the club head for improved performance. Another benefit over conventional stainless steel hosels is that the tube neck is softer and more flexible, and thus less likely to cause breakage of the relatively brittle graphite or composite golf club shaft. The intensity of stresses which the neck of the shaft might otherwise experience on impact is therefore reduced.
[0016] In golf clubs where the shaft extends directly into the head or hosel, the weakest point is where the shaft connects to the hosel. The tube neck forces the shear point or twisting point up higher on the shaft, where the shaft is stronger and more resistant to breakage.
[0017] In one example, the hosel had a length of 2.5 inches, an outer diameter of 0.44 inches, and an internal diameter of 0.33 inches. The length of the knurled end portion 32 was 0.90 inches.
[0018] The bonding of the tube in a blind bore in solid material at the heel of the club head provides a strong support for the hosel along the entire length of the connection. The roughening of the adhered surfaces of the hosel tube and bore enhances the adhesive bond by allowing more adhesive in the grooves or depressions in each surface.
[0019] Because the tube neck extends parallel or straight directly into the head, the club will be easier to align in play. There is little or no flare at the intersection with the head, and this will not interfere with the player's line of sight in aligning the ball striking face.
[0020] Although a preferred embodiment of the invention has been described above by way of example only, it will be understood by those skilled in the field that modifications may be made to the disclosed embodiment without departing from the scope of the invention, which is defined by the appended claims.
1. A golf club head, comprising:
a body having a front face, a rear wall, an upper wall, lower wall, a heel portion of solid material, and a toe, and an internal hollow cavity;
the heel portion having a bore extending inwardly from said upper wall at a selected angle in the solid material of said heel portion; and
a separate hosel tube having a first end portion secured in said bore and a second end portion projecting out of said bore.
a body having a front face, a rear wall, an upper wall, lower wall, a heel portion of solid material, and a toe, and an internal hollow cavity;
the heel portion having a bore extending inwardly from said upper wall at a selected angle in the solid material of said heel portion; and
a separate hosel tube having a first end portion secured in said bore and a second end portion projecting out of said bore.
2. The head as claimed in Claim 1, wherein the first end portion of the hosel tube has
a knurled outer surface.
3. The head as claimed in Claim 2, wherein the knurls comprise axially extending ribs.
4. The head as claimed in Claim 1, wherein the bore has a roughened cylindrical surface.
5. The head as claimed in Claim 4, wherein the surface roughening in said bore comprises
grooves.
6. The head as claimed in Claim 4, wherein the roughened cylindrical surface has screw
threads forming said surface roughening.
7. The head as claimed in Claim 1, wherein said bore terminates short of said cavity
and lower wall.
8. The head as claimed in Claim 1, wherein said body and hosel tube are of forged aluminum
alloy material.
9. The head as claimed in Claim 8, wherein said body is of 7075 T6 aluminum alloy and
said hosel tube is of 6061 aluminum alloy.
10. The head as claimed in Claim 1, wherein the body is made of forged metallic material
and said cavity is milled out through the lower wall of the body to provide selected
wall thicknesses at said front wall, rear wall, upper wall, heel portion and toe,
and a separate sole plate is secured across the cavity at said lower wall, the bore
terminating short of said sole plate.
11. The head as claimed in Claim 1, including adhesive material between the opposing surfaces
of said tube and bore for securing said tube in said bore.