US Patent 7048645 Golf club shaft

A golf club shaft whose outer diameter is set to 9.5 to 12 mm in at least one portion of a range from a tip thereof to a position located at 25% of the distance from the tip to its butt. The minimum value of a flexural rigidity (EI) is set to 1.00 to 2.50 kg·m2. A reinforcing layer is formed in the region disposed from the tip to the position located at about 25% of the distance from the tip to the butt. The layer includes at least one straight layer whose reinforcing fiber has a tensile modulus of elasticity of 5 to 15 ton/mm2 and is parallel with an axis of the shaft and one angular layer whose reinforcing fiber has a tensile modulus of elasticity of 24 to 40 ton/mm2 and an orientation angle of ±20 to 65°.