Patent ID: 6213888
Filing Date: 2001-04-10
Classification: A63B,G01N

Abstract:
A method of classifying a golf club shaft, wherein the golf club shaft comprises:a first strain gauge attached to a first side of said shaft facing a striking direction configured to detect a strain H in the striking direction of said shaft;a second strain gauge attached to a second side of said shaft facing an address direction at right-angles to the striking direction configured to detect a strain V in the address direction of said shaft;a third strain gauge configured to measure a twist of said shaft;said shaft comprising:detecting signals from the first strain gauge, the second strain gauge and the third strain gauge;generating an H-V graph on rectangular coordinates with the strain H in the striking direction and the strain in the addressing direction being combined; andclassifying the shaft into four types, an I-type shaft, a P-type shaft, a D-type shaft and a J-type shaft, each having a torque, according to the H-V graph associate with a swing of a golfer;wherein the torque of said I-type shaft is between 5.6.degree. and 7.2.degree., the torque of said P-type shaft is between 4.6.degree. and 5.0.degree., the torque of said D-type shaft is between 4.0.degree. and 4.4.degree., and the torque of said J-type shaft is between 3.4.degree. and 3.8.degree..