GOLF CLUB HEAD HAVING A COMPOSITE CROWN

Abstract

A golf club head has a high COR, is durable, and has desirable acoustic qualities. The club head includes a body portion, a striking face and a crown forming a hollow cavity of at least 150 cc in volume. The body portion defines a front opening and an upper opening, and it includes a sole and a side section that extends rearward of the front opening. The striking plate is secured to the body portion, enclosing the front opening. While partially assembled, final weighting and/or other attachment of other members to the inner surface of the club head can be preformed, as desired. The crown is secured to the body portion, enclosing the upper opening. A surface veil may also be provided about a junction of the crown and body.

Claims

1-20. (canceled)

21. A golf club head, comprising: a body having a sole, a front portion defining a front opening, a top portion defining an upper opening, and a side portion, the side portion extending rearward of the front and having toe, rear, and heel regions, a hosel extending outward from the top portion proximate the heel region, wherein the body is comprised of a metallic material having a density of at least about 4 g/cc, the upper opening located solely in the top portion of the body and comprising at least 25% of a total area of the top portion; a striking plate securely attached to the body portion and enclosing the front opening; a support member located solely in the top portion of the body and surrounding the upper opening; and a crown supported by and secured to the support member, thereby enclosing the upper opening, a first portion of the crown being sized to sit on the support member such that the first portion overlaps at least a portion of the support member, thereby forming a junction between the first portion of the crown and the body, the crown incorporating composite material having a density between 1 g/cc and 2 g/cc, the crown having a maximum thickness no greater than about 2 mm; wherein the crown incorporating composite material weighs at least 20% less than a weight of a crown sized to sit on the supporting member and formed of the same metallic material of the body.

22. The golf club head of claim 21, wherein the composite material has a 50% to 70% fiber volume ratio and a density between about 1.4 g/cc and about 1.65 g/cc.

23. The golf club head of claim 21, wherein the golf club head has a maximum coefficient of restitution of at least 0.80 and the striking plate has a thickness in a range of from about 1.5 mm to about 4 mm.

24. The golf club head of claim 21, wherein the support member is located on an annular lip.

25. The golf club head of claim 24, wherein a shoulder is arranged adjacent to at least a front portion of the annular lip.

26. The golf club head of claim 25, wherein the first portion of the crown is sized to abut and cover the annular lip of the body such that a side edge of the first portion is proximate to the shoulder, thereby forming the junction between the first portion of the crown and the body.

27. The golf club head of claim 25, wherein the shoulder is a distance (D1) of at least 7 mm rearward from the front of the golf club head.

28. The golf club head of claim 27, wherein the volume is at least 350 cc.

29. The golf club head of claim 27, wherein the crown is comprised of at least four plies of uni-tape standard modulus graphite.

30. The golf club head of claim 29, wherein the at least four plies are oriented at any combination of 0, +45, 45 and 90.

31. A golf club head, comprising: a body having a sole, a front portion defining a front opening, a top portion defining an upper opening, and a side portion, the side portion extending rearward of the front and having toe, rear, and heel regions, a hosel extending outward from the top portion proximate the heel region, wherein the body is comprised of a metallic material having a density of at least about 4 g/cc, the upper opening located solely in the top portion of the body and comprising at least 25% of a total area of the top portion; a striking plate securely attached to the body portion and enclosing the front opening; a support member located solely in the top portion of the body and surrounding the upper opening; and a crown supported by and secured to the support member, thereby enclosing the upper opening, a first portion of the crown being sized to sit on the support member such that the first portion overlaps at least a portion of the support member, thereby forming a junction between the first portion of the crown and the body, the crown incorporating composite material having a 50% to 70% fiber volume ratio and a density between about 1.4 g/cc and 1.65 g/cc, and wherein the crown has a maximum thickness no greater than about 2 mm.

32. The golf club head of claim 33, wherein the body is formed of titanium and the volume is at least 350 cc.

33. The golf club head of claim 33, wherein the crown is comprised of at least four plies of uni-tape standard modulus graphite.

34. The golf club head of claim 33, wherein the golf club head has a maximum coefficient of restitution of at least 0.80 and the striking plate having a thickness in a range of from about 1.5 mm to about 4 mm.

35. A golf club head comprising: a body having a sole, a front portion, a top portion defining an upper opening, and a side portion, the side portion extending rearward of the front and having toe, rear, and heel regions, a hosel extending outward from the top portion proximate the heel region, an upper edge being defined between the front portion and the top portion, the upper opening located solely in the top portion of the body and a support member located solely in the top portion of the body and surrounding the upper opening, wherein the body is comprised of a metallic material having a density of at least about 4 g/cc; a crown secured to the top portion and covering the upper opening and the support member, a first portion of the crown being sized to abut the support member such that the first portion overlaps the support member and is joined to the support member by adhesive thereby forming a junction between the first portion of the crown and the body, the crown incorporating composite material and having a density between 1 g/cc and 2 g/cc, the crown having a maximum thickness no greater than about 2 mm; and a shoulder extending adjacent to at least a frontward portion of the support member, the shoulder being a distance of at least 7 mm rearward from the upper edge; wherein the golf club head has a maximum coefficient of restitution of at least 0.80 and the body.

36. The golf club head of claim 35, wherein the upper opening comprises at least 25% of a total area of the top portion.

37. The golf club head of claim 36, further comprising a striking plate securely attached to the body portion and enclosing a front opening in the front portion; wherein the body is formed of steel.

38. The golf club head of claim 36, further comprising a striking plate securely attached to the body portion and enclosing a front opening in the front portion; wherein the body is formed of titanium.

39. The golf club head of claim 38, wherein at least one of the crown and the striking plate is attached by adhesive bonding.

40. The golf club head of claim 39, wherein the upper opening comprises at least 60% of a total area of the top portion.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Embodiments of the present invention will now be described, by way of example only, with reference to the following drawings in which:

[0023] FIG. 1 is a partially exploded perspective view of a preferred embodiment of a club head in accordance with the invention, depicting a crown separated from a body portion.

[0024] FIG. 2 is a cross-sectional view of the club head of FIG. 1, depicting the crown in place.

[0025] FIG. 3 is a cross-sectional view of a junction of the crown and body portion of the club head of FIG. 1.

[0026] FIG. 4 is a cross-sectional view of a second preferred embodiment of a golf club head in accordance with the invention.

[0027] FIG. 5 is a cross-sectional view of a junction of the crown and the body portion of the club head of FIG. 4.

[0028] FIG. 6 is a partially exploded view of another preferred embodiment of a club head in accordance with the invention, depicting the composite crown separated from the metal body.

[0029] FIG. 7 is a perspective view of a striking face and a body portion of a preferred embodiment of a golf club head in accordance with the invention, depicting a rear surface of the striking face.

[0030] FIG. 8 is a partially exploded perspective view of a third preferred embodiment of a golf club head in accordance with the invention, depicting a crown, including a surface veil covering a top portion of the club head, separated from a body portion.

[0031] FIG. 9 is a partially exploded perspective view of a fourth preferred embodiment of a golf club head in accordance with the invention, depicting a crown, including a surface veil covering a junction between the crown and body portion, separated from a body portion.

[0032] FIGS. 10A-10C are cross-sectional views of a junction of the crown and the body portion of the club head of FIG. 9, depicting exemplary steps for applying the surface veil.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0033] With reference to the illustrative drawings, and particularly FIG. 1, there is shown a golf club head 10 having a crown 12 formed of composite material not yet attached to a body 14 of a golf club head, to enclose an opening 16. The body is formed of any metal, such as an aluminum, steel or titanium alloy, for example. The body may be cast to form a front 18, a sole 20, a top portion 22 and a side portion 24. At the front, a striking plate 26 is separately formed and attached to the front of the body in any manner known to those skilled in the art (see FIGS. 4 and 5). The striking plate may be formed of a different alloy or grade of the same metal as the body, or the plate may be a different metal or a composite material, as desired. If metallic, the striking plate is welded to the front 18; if made of a composite material, the striking plate may be adhesively bonded to the front 18.

[0034] In alternative embodiments, the metal body may comprise three or more portions welded together, where the portions are forged, cast or stamped pieces or any mix thereof. Or, the body may be cast except for a separate sole plate that is attached in the appropriate location. The body may also include one or more attached members, such as weighting elements, that may comprise a metal or other material having a different density than the material of the rest of the main body.

[0035] The side portion 24 extends rearwardly of the front 18 and has a toe region 28, a rear region 30 and a heel region 32 formed above the sole 20. A hosel 34 is provided at the heel end of the body for attachment of a shaft (not shown). The top portion 22 of the body 14 extends rearwardly from an upper edge 36 of the front 18 of the club head, above the side portion 24. Thus, the sole 20, top portion 22, front 18 and side portion combine with the crown 12 to form a hollow body having a volume of at least 150 cubic centimeters (cc) and up to 500 cc.

[0036] As more clearly shown in FIG. 2, the cast body 14 includes an annular rim 38 at the opening 16 in the top portion 22 that includes a ledge 40 that acts as a support member for the crown 12. Alternatively, the support member may comprise a plurality of tabs. The size and shape of the support member is preferably chosen to minimize the required overlap with the crown or the mating surface area of the crown and top portion.

[0037] Referring to FIG. 3, the rim 38 extends a distance D.sub.1 of at least 7 mm rearward from the upper edge 36 of the front 18, with a shoulder 42 defining the ledge 40 which preferably extends an additional distance D, of at least 7 mm. The rim preferably extends between 8 mm and 12 mm, and more preferably about 10 mm, from the upper edge 36 while providing advantages of the present invention. Similarly, the ledge preferably extends between 8 mm and 12 mm, Preferably, an adhesive such as Hysol two part epoxy 9460 or, alternatively, 3M DP460NS, is used to attach the crown 12 onto the ledge 40, abutting the shoulder 42.

[0038] The striking plate 26 may be formed to have a rear surface with a flat portion 27a and a tapered portion 27b, such as are shown, e.g., in FIG. 4.

[0039] The opening 16 in a central section 44 of the top portion 22 comprises at least 25% (see FIG. 6), and preferably comprises at least 60%, of the total area of the top portion 22. More preferably, the opening is at least 75% of the total area of the top portion. Thus, there is a significant weight savings afforded by replacing a similarly sized metal crown with the crown 12 described herein. The difference in weight between the metal and composite materials may be redistributed in the club head 10 to manipulate the center of gravity of the club head, such as by providing a weight pad 46 on an interior surface 48 of the sole as shown in FIG. 4. Such a weight pad is preferably formed of material having a higher density (e.g., tungsten) than the material of the body 14 of the club head and is attached to the sale 20; although, a weight pad may alternatively be cast as a thickened portion of the sale.

[0040] Tables I and II show exemplary materials for the body 14 of the club head and the crown 12, respectively. The body 14 preferably has a thin-wall construction, wherein the thicknesses of the sole 20 and side portion 24 is in the range of 0.8 mm to 2 mm and the top portion thickness is in the range of 0.7 mm to 2 mm. The thickness of the front portion 26 is preferably in the range of 1.5 mm to 4 mm. The crown is also of a thin construction, having a thickness T.sub.C of no more than about 2 mm, preferably less than 1.5 mm, and more preferably about 1 mm. In the preferred embodiment of FIGS. 1-3, the thickness of the top portion 22, including the ledge 40, is approximately 1 mm so that the shoulder 42 extends about 2 mm from an outer surface 50 of the top portion to an inner surface 52 of the ledge.

TABLE-US-00001 TABLE I EXAMPLES OF METALS FOR THE BODY OF A CLUB HEAD Density Ult. Tens. Mod. of Material Type (g/cc) Str. (MPa) Elast. (GPa) Hardness Mg AZ81A-T4 1.8 275 45 Brinell 55 Al 1201 Alloy 2.85 430 72 Ti 6A1-4V 4.43 950 113.8 Brine1l334 Rockwell C 36 Ti 15-3-3-3 4.76 790 82 Rockwell B 95 Carpenter 7.76 1100 200 Brinell 318 Custom 455 Rockwell C 34

TABLE-US-00002 TABLE II EXAMPLES OF COMPOSITE MATERIALS FOR A CLUB HEAD CROWN Density Ult. Tens. Modulus of Composite Fiber Material (g/cc) Str. (MPa) Elasticity (GPa) Carbon Filled Nylon 1.4 103 13 DuPont Kevlar 49 1.44-1.45 2760 120-125 Fiber, diam 11.9 um Thornel VCB-20 1.88 1380 138 Carbon Cloth
A graphite-epoxy composite material, for example, with a 50% to 70% fiber volume ratio would have a density between about 1.4 g/cc and 1.65 g/cc.

[0041] A golf club head constructed in this manner advantageously improves durability since the junction of the striking plate 26 with the top portion 22 is subject to a lesser force at impact with a golf ball. The use of the crown 12 on the metal body 14 also increases COR. Further, the golf club head having a crown on a metal body advantageously provides acoustic qualities judged more appealing to golfers.

[0042] In one club head tested by the inventors, a 300 cc hollow body was formed of a stainless steel alloy. A large area, 1 mm thick crown was formed of five plies including four plies of a uni-tape of standard modulus graphite and one ply of a woven graphite cloth. The four plies of uni-tape were assembled at 0,45, 45 and 90 degrees and had a fiber areal weight (FAW) of about 40 grams per meter squared (g/m.sup.2). The standard modulus is approximately 33 Mpsi for the fiber with about 600 Kpsi tensile strength. In comparison, an alternative, and more expensive, ultrahigh modulus fiber (satellite grade) comprises about 57 Mpsi. FAW may range from about 20 to 200 g/m.sup.2, and preferably the composite plies for the crown are in the range of 70 to 180 g/m.sup.2. More preferably, the composite plies for the crown are in the range of 120 to 16 Qg/m.sup.2.

[0043] The resultant mass of the crown 12 is about 10 grams. This is about a 50% reduction in the mass compared to a crown formed of the steel material of the rest of the club head. The calculations of the weight savings must take into account the presence of the ledge 40 with the crown, as well as the adhesive. Generally, the weight savings is at least 20% compared to an all metal body. The weight pad 46 may then be added to achieve a total mass approximately equivalent to an all metal body.

[0044] The crown 12 may alternatively be formed of more or less plies, and instead of the top ply being a woven graphite cloth, the top ply may be another uni-tape that is painted to achieve the desired aesthetic look of the club head. The top ply is preferably oriented at 0 or 90 degrees. The molding of the crown may be performed using methods known to those skilled in the art and preferably comprises a matched mold to achieve a net shape that requires little finishing and flash removal prior to its attachment to the body 14 of the club head.

[0045] Another club head tested by the inventors utilized a titanium alloy body for the club head, with a crown 12 formed of a thermoplastic material. Preferably, the crown is an injection-molded nylon or polyphenylene sulfide (PPS) material, using 3M DP460NS adhesive for attachment to the metal body. The nylon may be used with or without glass or carbon fiber and preferably has a density between 1 g/cc and 1.7 g/cc. Alternatively, the PPS material may be used with or without glass or carbon fiber and preferably has a density between 1.3 g/cc and 2.0 g/cc. Replacing the crown of the titanium alloy club head results in about 35% savings in weight. In general, the weight savings is at least 15% compared to an all metal body.

[0046] The replacement of the crown of a metal club head provides the advantage of weight savings and/or redistribution of mass to the sole, for example. A weight pad on the sole, or elsewhere on the body, may be integrally formed or be a separately formed and attached mass, the resulting weight being comparable to an all metal club head of the same volume.

[0047] Because of the access afforded by the opening in the top of the club head, a rear of the striking face 54 is accessible during manufacture for the addition of a face reinforcing member 56 formed of metal or composite material and securely attached behind the sweet spot, as shown in FIG. 7. Thus, a thin titanium alloy striking face can be strengthened or otherwise enhanced in performance. Similarly, any number of additional members may be attached elsewhere on any inner surface of the club head.

[0048] The use of the aforementioned materials, composite or plastic, for the crown 12 allows the use of a lighter weight material that may result in the top of the club head having a stiffness similar to the heavier, metal sale. This stiffness matching may be advantageous for high COR golf club heads.

[0049] The golf club head 10 can be assembled with the aid of adhesive bonding. In a preferred method of manufacture, the striking face 22 is securely attached to the body 14, enclosing a front opening. While partially assembled, final weighting and/or other attachment of other members to the inner surface of the club head can be preformed, as desired. Next, the crown is secured in place, forming the top section of the club head. Preferably, the crown 12 is of a material having a density less than 2 g/cc and has a thickness no greater than 2 mm. At least one of the crown and the striking plate is attached by adhesive bonding to the opening in the body. In one embodiment, the mating surfaces of the crown and ledge 40 may be prepared by sandblasting to enhance bonding. Other steps may be performed in order to prepare and/or finish the final club head, as known to those skilled in the art.

[0050] With reference now to FIGS. 8 and 9, the golf club head may further include a surface veil 58 sized to cover the junction between the crown portion 12 and the body portion 14. The surface veil can include plies of composite material. As shown in FIG. 8, the surface veil can be sized to entirely cover the junction between the crown and body portion and the outer surface of the crown. Alternatively, as shown in FIG. 9, the surface veil can be configured to be disposed about the crown to cover the junction between the crown and the body portion. The surface veil aids in preventing cracking and peeling of the club head's surface. In the exemplary embodiments, the surface veil is formed of two additional plies of the material used with the crown portion, as discussed above. In other preferred embodiments, the crown portion is formed of a first lightweight material, as discussed above, e.g., carbon fiber plies, and the surface veil is formed of a second lightweight material, such as discussed above, e.g., a glass composite.

[0051] With reference now to FIGS. 10A-10C, an exemplary method of attaching the surface veil 58 is depicted. As shown in FIG. 10A, an obtuse depression 60 is provided at the junction between the crown portion 12 and the body portion 14. The depression is preferably formed by providing a taper to at least one of the side edge 62 of the crown portion and the shoulder 42 of the body portion. In the exemplary method, both the side edge and the shoulder are tapered, defining an angle , which is preferably greater than 90 degrees and less than 180 degrees. The surface veil is attached above the junction such that it at least partially fills the depression (FIG. 10B). Once in place, the outer surface of the club head undergoes additional treatment, e.g., grinding and/or sanding, to provide a smooth, finished surface (FIG. 10C).

[0052] It should be appreciated from the foregoing the present invention provides a golf club head having a high COR that is durable and has desirable acoustic qualities. The club head includes a body portion, a striking face and a crown forming a hollow cavity of at least 150 cc in volume. The body portion defines a front opening and an upper opening, and it includes a sole and a side section that extends rearward of the front opening. The striking plate is secured to the body portion, enclosing the front opening. While partially assembled, final weighting and/or other attachment of other members to the inner surface of the club head can be performed, as desired. The crown is secured to the body portion, enclosing the upper opening. A surface veil may also be provided about a junction of the crown and body. The crown has a maximum thickness no greater than about 2 mm. The density of the crown is less than the density of the body portion. Beneficially, the golf club head has a coefficient of restitution of at least 0.80.

[0053] Although the disclosed technology has been disclosed in detail with reference only to the preferred embodiments, those skilled in the art will appreciate that additional golf club heads can be made without departing from the scope of the invention(s) disclosed herein. Accordingly, the disclosed invention(s) is at least as broad as the full scope claims set forth below and their equivalents.