| 摘要 |
<p>PURPOSE:To improve a resiliency and, simultaneously, to reduce an impact force by providing a spiral groove to be right-wound from the viewpoint of a grip to both or either of the outer circumference or inner circumference of the pipe shaft of a golf club. CONSTITUTION:On both or either surface of the outer surface or inner surface of the shaft from the grip up to a head, a spiral recessed groove is formed. The shape of the recessed groove is made into a smooth circular arc surface such as a U shape, and the size, wide and depth are made suitable according to a shift. The direction of a spiral is made into a right winding from the grip towards the head, the groove is made into one successive groove, and two to three lines of grooves may be provided in the same pitch.</p> |
