US 7,513,837 B2
Three-piece solid golf ball
Junji Umezawa, Chichibu (Japan); and Kazufumi Tabata, Chichibu (Japan)
Assigned to Bridgestone Sports Co., Ltd, Tokyo (Japan)
Filed on Sep. 13, 2006, as Appl. No. 11/519,866.
Application 11/519866 is a division of application No. 11/056267, filed on Feb. 14, 2005, granted, now 7,140,980.
Claims priority of application No. 2004-038651 (JP), filed on Feb. 16, 2004.
Prior Publication US 2007/0015606 A1, Jan. 18, 2007
Int. Cl. A63B 37/06 (2006.01)
U.S. Cl. 473—373 6 Claims
 
1. A three-piece solid golf ball having a solid core, an intermediate layer enclosing said solid core, and a cover layer enclosing said intermediate layer and having a large number of dimples formed in its surface, wherein the core deforms as much as 2.6 to 3.2 mm under a load which changes from 10 kg to 130 kg, the cover layer is formed mainly from thermoplastic polyurethane such that it has a lower hardness than said intermediate layer, a surface hardness of said cover layer being 58 to 64 in terms of Shore D hardness, with the difference in hardness between the cover layer and the intermediate layer being 4 to 10 in terms of Shore D hardness, the intermediate layer and the cover layer have a total thickness of 2.2 to 3.0 mm, the cover layer has a thickness of 0.8 to 1.3 mm, and the dimples have at least four different diameters and/or depths, with the diameter being about 2 to 6 mm, the average depth being 0.125 to 0.150 mm, and amount to 330 to 390 in all,
wherein the intermediate layer is compounded with trimethylolpropane.