抄録
The mechanical properities of golf clubs are represented mainly by the flex(flexural property)and the torque-degree(torsional property). The initial speeds and the fly-out directions of balls hit by golf clubs with different torque-degree shafts were evaluated using a golf shaft swing machine. It was found that golf clubs with low torque-degree shafts can achieve higher initial speeds and are more stable in the fly-out direction than clubs with high torque-degress shafts. The reasons are as follows.1) The degree of torsion of low torque-degree shafts during the time the golf club head hits(touches)the ball is lower than that of high torque-degree shafts.2) A golf club shaft exhibits torsional vibration behavior during the swing even before the impact point. In the case of low torque-degree shafts, the amplitude of vibration is smaller and the face of the club head returns to a proper angle.
