| 摘要 |
<p>PURPOSE:To obtain a shaft suitable for wide range of golfers by distributing the rigidity ratio of bending rigidity and torsional rigidity within a specified range over the entire length of the shaft, by which energy losses are eliminated and a flying distance is increased as the generation of local bending and twisting is obviated. CONSTITUTION:The rigidity ratio GI/EI=K of the bending rigidity at the arbitrary section of the shaft consisting of fiber-reinforced plastics, designated as EI, and the torsional rigidity, designated as GI, is specified to the range expressed by following equation over the entire length of the shaft: ax+b<K< ax+c, where x is the arbitrary size (mm) from the top end of the shaft, a=0 to 2/1143, b=0 to 0.8, c=0.8 to 2.0. The layers of the shaft are constituted of an inside layer 2 which is formed by using carbon fiber sheets and winding these sheets to a shape having staircase steps by increasing the number of the winding layers toward the hand side at 45 deg.+ or -10 deg. orientation angle and an outside layer 1 which is formed by impregnating a resin to carbon fiber sheets or carbon fibers and winding such sheets or fibers at 0 to 30 deg. orientation angle. The generation of the local bending and twisting is obviated by specifying the rigidity ratio GI/EI=K within the regulated range.</p> |
