| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a method and apparatus for quickly and reliably determining the preferred angular orientation of a golf club shaft. <P>SOLUTION: The referred orientation, or planar oscillation plane, of the golf club shaft (110) is located by measuring the oscillation (20, 21) of the shaft (110) when an impulse is applied. Preferably, the out-of-plane oscillation is measured at a large number of angular positions to the axis of the shaft (110), and the principal planar oscillation plane is identified by a pair of opposed angular positions in which the out-of-plane oscillation is smallest. The location of the preferred orientation may be marked on the shaft (110) and used to manufacture a golf club with the planar oscillation plane in a predetermined orientation. The straightness of the shaft (110) can also be determined by deriving its spring constant from its oscillation frequency and then measuring the restoring force when the shaft (110) is deflected by the same nominal amount at different angular positions. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
