| 摘要 |
<p>PROBLEM TO BE SOLVED: To improve ball hitting directionality and an average carry by setting an outside diameter of a shaft for a golf club to a specific range over a specific dimension from the butt end. SOLUTION: A butt side thick diameter part having an outside diameter of 18 to 30mm is formed over 200 to 400mm of the butt end of a shaft. Since this part is a part gripped by both hands at using time, it requires at least 200mm, and when it exceeds 400mm, the shaft becomes too hard, or a kick point becomes low since weight increases. When the outside diameter is less than 18mm, a wrist easily bends at backswing time, and it is hardly gripped when exceeding 30mm. This butt side thick diameter part is easily manufactured by forming a taper of about 5/1,000mm. It is better to set flexural rigidity of this thick diameter part to 3 to 6×10<6> kgf.mm<2> . This shaft is molded by winding a prepreg around metallic core metal 1 on which the total length is about 1,600mm and a thin diameter is about 3.3μmϕand a thick diameter is about 18.8mmϕ. Therefore, a probability of striking on a sweet spot is enhanced, and directional stability and an average carry can be improved.</p> |
