Patent ID: 8936515
Filing Date: 2015-01-20
Classification: A63B

Abstract:
1. A golf club shaft manufactured using a plurality of prepreg sheets, wherein the plurality of prepreg sheets comprises full length sheets disposed all over in a shaft axis direction and a partial sheet or partial sheets partially disposed in the shaft axis direction; the number of plies is substantially an integer in all the full length sheets; the full length sheets comprise four or more bias sheets; circumferential winding start positions of the bias sheets are dispersed in four or more positions; the bias sheets have two base sheets (a first base sheet and a second base sheet) and two adjusting sheets (a first adjusting sheet and a second adjusting sheet); the two base sheets have an absolute fiber angle θb of 40 degrees or greater and 50 degrees or less; the two adjusting sheets have an absolute fiber angle θt of 15 degrees or greater and 75 degrees or less, and the absolute fiber angle θt is less than the absolute fiber angle θb; and if the circumferential winding start position of the first base sheet is defined as Pa; the circumferential winding start position of the second base sheet is defined as Pb; the circumferential winding start position of the first adjusting sheet is defined as Pc; and the circumferential winding start position of the second adjusting sheet is defined as Pd, each of the positions Pa, Pb, Pc, and Pd corresponds to any one of the following four circumferential positions P the circumferential position P the circumferential position P the circumferential position P the circumferential position P