Metal matrix composite shafts for golf clubs
AssigneeJas. D. Easton, Inc.
InventorsLarry Carlson, Kirk Litzinger
Life of this patent
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Abstract
Formed tubular sporting articles subjected to repeated flexure such as golf club shafts are made from metal matrix composite materials (MMCs) in which a metal alloy matrix is discontinuously reinforced with undissolved particles or platelets in proportions to result in an article having a variable wall thickness, and a minimum modulus of elasticity of 10.4 and a minimum yield strength and minimum modulus of elasticity related by the equation: Y=71+6.84(E−10.4) where Y is yield strength in KSI and E is modulus of elasticity in units×106 psi. The sporting articles are lighter than conventional and have a modulus of elasticity substantially less than that of ordinary MMCs.
Claims14
A golf shaft formed from a metal matrix composite material, said shaft comprising a handle portion, a tapered portion and a tip portion, the final dimensions of at least said tapered portion and said tip portion being re-formed from the starting dimensions of a tubular metal matrix composite material starting stock to provide a shaft with variations in wall thickness, said metal matrix composite comprising a 7XXX series aluminum alloy matrix having discontinous reinforcement particles therein, a maximum modulus of elasticity of 12.5, a minimum modulus of elasticity and a minimum yield strength being related by the equation:
- Y=71+6.84(E−10.4)
- where Y is yield strength in kilopounds per square inch and E is modulus of elasticity in millions of pounds per square inch, and wherein a minimum modulus of elasticity is no lower than 10.4 and a minimum yield strength is no lower than 71.
Dependencies are inferred from the claim text.