Patent ID: 6695719
Filing Date: 2004-02-24
Classification: A63B

Abstract:
Method of selecting the most suitable material as a cover layer of a golf ball from a specimen which is made of a synthetic resin and has a viscoelastic characteristic which comprises:(i) arranging said specimen of said cover layer between input bar and an output bar in a straight line, wherein the input bar has a first and a second strain gauge, and the output bar has a third and fourth strain gauge, (ii) hitting a front gauge of the input bar at impact speed of 14.0 m/sec to generate an incident strain wave and a reflected wave in the input bar, and a transmitted strain wave propagating in the input bar, the specimen and the output bar, (iii) measuring said incident strain wave and said reflected strain wave with first and second strain gauges installed on the input bar and measuring a transmitted strain wave with a third and fourth strain gauges installed on the output bar, (iv) computing Young's modulus and a loss factor of each specimen from a viscoelastic characteristic value thereof, obtained by estimating the incident strain wave, the reflected strain wave and the transmitted strain wave, and (v) selecting the most suitable specimen whose Young's modulus lies in the range of 100 Mpa to 350 Mpa both inclusive and whose loss factor lies in the range of 0.2 to 0.45 both inclusive as a material of the cover layer of the golf ball.