| 摘要 |
The effect of the kick point of a shaft in swinging, is enhanced by joining in tandem a shaft portion whose rigidity is extremely low and other shaft portions of normal hardness. A golf club shaft formed by fitting into shaft portions, whose rigidity EI defined by Equation 1 equals 3.66 to 10.76, another portion whose rigidity is extremely low, EI being in the range of 1.12 to 2.47, wherein a kevlar<TM> fiber shaft, for instance, is used as the low rigidity portion, and the length of the non-overlapping part is at least 100 mm. Equation 1: EI = rho L<3>/48 delta (wherein the length (L) is 300 mm and the deflection ( delta ) is 2.00 mm, while the load ( rho ) is variable). |
