초록

A hollow golf club shaft of circular cross-section comprises a tubular cover layer formed from an isotropic material and a tubular core layer formed from a non-isotropic material, wherein the cover layer and the core layer coextend substantially the entire length of the shaft.

대표청구항 ▼

1. A hollow golf club shaft of circular cross section comprising at least one tubular cover layer comprising at least one isotropic material, and at least one tubular core layer comprising at least one reinforcement material chosen from carbon fibers, graphite fibers, glass fibers, quartz fibers, bo

1. A hollow golf club shaft of circular cross section comprising at least one tubular cover layer comprising at least one isotropic material, and at least one tubular core layer comprising at least one reinforcement material chosen from carbon fibers, graphite fibers, glass fibers, quartz fibers, boron fibers, ceramic fibers, ceramic whiskers, metal-coated fibers, ceramic-coated fibers, diamond-coated fibers, carbon nanotubes, extended-chain polyethylenes, poly-p-phenylenebenzobisoxazole fibers, metal fibers, polythenes, polyarylates, polyacetals, liquid crystalline polymers, aromatic polyesters, and polyallylates, the reinforcement material being impregnated with at least one vibration damping thermosetting or thermoplastic resin chosen from epoxy, polyester, polystyrene, polyurethane, polyurea, polycarbonate, polyamide, polyimide, polyethylene, polypropylene, polyether, polyvinyl halide, polyvinylidene halide, nylon, nylon 6, polyphenylene sulfide, polyether ether ketone, polyether ketone ketone, polyamide imide, polyether imide, polyaryl sulfone, polyether sulfone, and liquid crystal polymer, wherein the vibration dampening thermosetting or thermoplastic resin has a loss factor of between about 0.2 and about 1.2 at 100 Hz and 68° F., a storage modulus of at least about 1,000 psi, and a Young's modulus of at least about 0.01 Mpsi, the cover layer and the core layer are conjoined and coextend substantially the entire length of the shaft, and the cover layer at an upper butt portion has a thickness of 0.001 inches to about 0.2 inches. 2. The shaft of claim 1, wherein the isotropic material of the cover layer comprises metal matrix composites, metals and alloys thereof comprising titanium, steel, stainless steel, aluminum, tungsten, nickel, copper, zinc, brass, bronze, magnesium, tin, gold, or silver. 3. The shaft of claim 1, wherein substantially all of the reinforcement material is aligned longitudinally along the shaft. 4. The shaft of claim 1, wherein the non-isotropic material is epoxy-impregnated carbon or graphite fibers, and wherein the carbon or graphite fibers are present in an amount of from about 10% to about 80% by volume of the core layer. 5. The shaft of claim 1, wherein the cover layer at the upper butt portion has a thickness of about 0.01 inches to about 0.15 inches. 6. The shaft of claim 1, wherein the cover layer has a weight of about 10 grams to about 80 grams. 7. The shaft of claim 1, wherein the isotropic material has a first Young's modulus of at least about 5 Mpsi. 8. The shaft of claim 7, wherein the resin has a second Young's modulus less than the first Young's modulus by at least about one order of magnitude. 9. The shaft of claim 7, wherein a volume ratio of the core layer to the cover layer is less than about 20:1. 10. The shaft of claim 1, wherein at least one location on the shaft has a thickness ratio of the cover layer to the core layer between about 5:95 and about 90:80. 11. The shaft of claim 1, wherein at least one location along the shaft has a thickness ratio of the cover layer to the core layer ranging from about 5:95 to about 90:10. 12. The shaft of claim 1, wherein an outer surface of the core layer is conjoined to an inner surface of the cover layer through structural adhesives, contact adhesion, physical bonding, or chemical bonding. 13. The shaft of claim 1, wherein an outer surface of the core layer is conjoined to an inner surface of the cover layer through structural adhesives comprising one-part heat-cured epoxies, two-part reaction-cured epoxies, two-part reaction-cured polyurethanes, acrylics, double-coated bonding tapes, pressure-sensitive adhesives, or heat-cured epoxy/acrylic hybrid adhesives. 14. The shall of claim 1, wherein the cover layer at the upper butt portion has a thickness of about 0.12 inches to about 0.2 inches. 15. The shaft of claim 1, wherein at least one location on the core layer has a thickness of less than about 0.3 inches. 16. The shaft of claim 1, wherein at least one location on the core layer has a thickness of about 0.18 inches to about 0.3 inches. 17. The shaft of claim 1, wherein a volume ratio of the core layer to the cover layer is less than about 20:1. 18. The shaft of claim 1, wherein the cover layer at the upper butt portion has a thickness of about 0.001 inches to about 0.12 inches, and the core layer at one location has a thickness of about 0.001 inches to about 0.18 inches. 19. The shaft of claim 1, wherein the shaft has an upper butt portion and a lower tip portion, and wherein the cover layer at the butt portion is different in thickness than the cover layer at the tip portion. 20. The shaft of claim 19, wherein the cover layer at the butt portion is thicker than the cover layer at the tip portion.