Patent ID: 6514158
Filing Date: 2003-02-04
Classification: A63B

Abstract:
A multi-piece golf ball of at least three layer structure comprising a core composed primarily of a rubber composition, an intermediate layer composed primarily of a thermoplastic resin enclosing the core, and a cover formed of a thermoplastic resin enclosing the intermediate layer, whereinthe core undergoes a deflection A (mm) under an applied load of 100 kg, and a sphere having the core enclosed with the intermediate layer undergoes a deflection B (mm) under an applied load of 100 kg, the ratio of A/B is at least 1.10/1, the ball has a first coefficient of restitution at a firing velocity of 25 m/s and a second coefficient of restitution at a filing velocity of 50 m/s, and the first coefficient minus the second coefficient is less than 0.100; wherein the cover has a plurality of dimples iD its surface, and the total of dimple volumes is from 250 mm3 to 450 mm3, provided that the volume of each dimple is determined with respect to an imaginary spherical surface which is given on the assumption that no dimples are formed in the ball surface, wherein the dimples have a diameter of 1.0 to 5.0 mm and a depth of 0.08 to 0.30 mm; and wherein two to six types of dimples are formed on the cover, each of the types is different in diameter and/or depth, and the total number of the dimples is 300 to 450.