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Golf club head with foam core

Golf club head with foam core description/claims

This invention relates generally to golf equipment and, in particular, to golf clubs.

Golf clubs such as drivers, irons and putters have club heads that are conventionally manufactured by investment casting, forging or machining from a solid bar. Use of materials with a high strength-to-density ratio such as titanium has been suggested to enable greater flexibility in designing golf clubs. Polymer foams have been utilized as cores in club heads of hollow metal drivers to prevent weld slag and other debris inside the club head from making the club head rattle; however, polymer foams provide negligible structural support for the face and crown of the club head. Conversely, a metallic or ceramic foam core would provide structural support for the face and other surfaces of the club head with an unprecedented strength to density ratio, which in turn, would enable unprecedented improvements in golf club performance.

FIG. 1 is a club head pre-form consisting of a rigid foam material incorporating features of the present invention;

FIG. 2 is the club head pre-form of FIG. 1 intercalated with a second material incorporating features of the present invention;

FIG. 3 is the club head pre-form of FIG. 2 formed into a club head body;

FIG. 4 is a schematic representation of applying a coating to the rigid foam composite club head body of FIG. 3.

FIG. 5 is a schematic representation of an alternative embodiment of applying a coating to the foam composite club head body of FIG. 3;

FIG. 6 is a cross-sectional view of a club head incorporating features of the present invention after the second material has been pyrolized; and

FIG. 7 is an alternative embodiment of a club head incorporating features of the present invention.

With reference to FIGS. 1-3, a club head pre-form 12 is formed of a first material such as metallic or ceramic foam that is rigid and has a high degree of porosity. The metallic foam preferably comprises a metallic material such as aluminum or titanium but may be composed of other metallic materials such as nickel, tin, zinc or other metals. The ceramic foam may be composed of ceramic materials such as silicon carbide, silicon nitride, vitreous carbon, boron carbide or other non-metallic materials. These foam materials have an inherently irregular outer surface of peaks and valleys.

Club head pre-form 12 may be manufactured in a closed-cell foam structure by injecting gas into the molten material and/or by mixing a foaming agent such as powdered titanium hydride into the alloy composition prior to melting. In the illustrative embodiment, however, club head pre-form 12 comprises an open-cell reticulated structure with interconnected voids which is formed by metalization of a polymer template such as polyurethane foam. In one aspect of the invention, metal such as nickel alloy is deposited onto a sponge-like non-metallic material such as polymer having a shape approximating at least a portion of a club head body such as a face insert. This forms a metallic foam member which is then covered with a coating that is preferably non-metallic material. In another aspect of the invention, metal is deposited onto a sponge-like non-metallic material in the shape of club head perform 12. Then, the club head perform 12 is formed into the shape of at least a portion of a club head body and, if desired, covered with a coating. The polymer template mentioned above is removed from the club head perform 12 by pyrolyzing to leave a reticulated rigid foam structure 14 composed of the pure metallic or ceramic material consisting of from 80% to 98% voids and therefore from 2% to 20% of the bulk density of an equivalent volume of solid material.

With reference to FIG. 2, once reticulated foam structure 14 is formed, it is intercalated with a second material 16 that fills the voids in rigid foam structure 14 to form a rigid foam composite pre-form 18 consisting of the rigid foam structure 14 and the second material 16. Second material 16 is denser than the metallic or ceramic foam forming the foam structure 14 and may comprise a thermoset plastic, a thermoplastic, wax or other organic material, which for reasons that are explained more thoroughly hereinafter, has a decomposition temperature (i.e., melts or otherwise decomposes into an easily removable substance) that is below the melting point of the club head pre-form 12. Preferably second material 16 is sufficiently rigid and machinable so that the composite pre-form 18 can be machined to have a substantially smooth outer surface. Alternatively, second material 16 may be a metallic material (e.g., tin-lead alloys) that has a lower melting point than the club head pre-form 12.

With reference to FIG. 3, composite pre-form 18 is formed (e.g., machined) into a rigid foam composite core 20 having the shape of a club head body. Because second material 16 is sufficiently hard and machinable, composite pre-form 18 can be formed by a conventional machining process into the core 20 having a substantially smooth outer surface notwithstanding the dissimilarity between the material properties of rigid foam structure 14 (e.g., metal/ceramic) and second material 16 (e.g., plastic).

Once core 20 has been properly shaped, a coating 22 is applied to the outer surface of core 20. In the illustrative embodiment of FIG. 4, coating 22 comprises an electroplated metallic material such as a conventional copper-nickel electroplating, but may be more exotic materials such as electrodeposited nanometals or other metallic materials suitable for use in electrodepositing processes. Because the surface of rigid foam composite core 20 is substantially smooth, the electrodeposited coating 22 also develops a substantially smooth outer surface notwithstanding the irregular outer surface of the rigid foam structure 14.

• Provisional Patent
• Utility Patent

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