| 摘要 |
A golf club shaft that is light in weight but which avoids problems related to a bending deformation of the section where these phenomena might otherwise occur. The bending strength of the shaft in the area sensitive to these phenomena is improved and the flexional and torsional stiffness characteristics are not significantly affected. Further, the mass and the mass distribution of the shaft are not significantly affected. According to one embodiment, the golf club shaft is tubular and includes a variable cross section along its length. The shaft has an enlarged butt at one end an a smaller radius tip at the opposite end. The shaft includes several layers of reinforcing fibers having different orientations with respect to the longitudinal axis, at least one of the layers being oriented at, or approximately at, 90 DEG with respect to the longitudinal axis at least over a portion of the shaft where the external radius/thickness ratio is greater than or equal to 4. More particularly, the invention relates to shafts which comprise a radius/thickness ratio that is greater than the ratio of a conventional shaft in the bending area of the shaft length, i.e., the area which experiences a greater bending deformation during the swinging motion. A higher radius/thickness ratio in the bending area allows the shaft to be lightened while keeping proper mechanical properties of stiffness and strength by use of regular modulus carbon fibers which are less expensive than ultra-high modulus fibers.
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