Solid golf ball

• US 7,357,732 B2
• Filed: 05/25/2007
• Issued: 04/15/2008
• Est. Priority Date: 09/14/2005
• Status: Active Grant

• Current Assignee: Bridgestone Sports Co Limited (Bridgestone Corporation)
• Original Assignee: Bridgestone Sports Co Limited (Bridgestone Corporation)
• Inventors: Watanabe, Hideo, Kasashima, Atsuki
• Primary Examiner(s): GORDEN, RAEANN
• Application Number:
  US11/802,833
• Publication Number:
  US 20070232412A1
• Time in Patent Office: 326 Days
• Field of Search: 473/378, 473/368, 473/351
• US Class Current: 473/368
• CPC Class Codes: A63B 37/0004 Surface depressions or protrusions
• CPC Class Codes: A63B 37/0007 Non-circular dimples
• CPC Class Codes: A63B 37/0008 Elliptical
• CPC Class Codes: A63B 37/0009 Polygonal
• CPC Class Codes: A63B 37/0018 Specified number of dimples
• CPC Class Codes: A63B 37/0019 Specified dimple depth
• CPC Class Codes: A63B 37/002 Specified dimple diameter
• CPC Class Codes: A63B 37/00215 Volume ratio
• CPC Class Codes: A63B 37/0031 Hardness
• CPC Class Codes: A63B 37/0033 Thickness
• CPC Class Codes: A63B 37/00621 Centre hardness
• CPC Class Codes: A63B 37/00622 Surface hardness
• CPC Class Codes: A63B 37/0063 Hardness gradient
• CPC Class Codes: A63B 37/0064 Diameter
• CPC Class Codes: A63B 37/0065 Deflection or compression
• CPC Class Codes: A63B 37/0074 Two piece balls, i.e. cover and core
• CPC Class Codes: A63B 37/0075 Three piece balls, i.e. cover, intermediate layer and core
• CPC Class Codes: A63B 37/0076 Multi-piece balls, i.e. having two or more intermediate layers
• CPC Class Codes: A63B 37/0084 Initial velocity
• CPC Class Codes: A63B 37/0089 Coefficient of drag
• CPC Class Codes: A63B 37/009 : Coefficient of lift
• CPC Class Codes: A63B 37/0096 : Spin rate

Abstract

A solid golf ball is composed of a solid core and a cover of one or more layers which encloses the core and has on a surface thereof numerous dimples. The solid core has a diameter of 38.7 to 39.6 mm and a deflection hardness of 3.0 to 4.0 mm. The cover has a Shore D hardness of 59 to 70 and has 313 to 371 dimples formed thereon. The ball has an initial velocity of at least 76.8 m/s, a coefficient of lift (CL) when hit of at least 0.165 at a Reynolds number of 70,000 and a spin rate of 2,000 rpm, and a coefficient of drag (CD) when hit of not more than 0.230 at a Reynolds number of 180,000 and a spin rate of 2,520 rpm. The golf ball has a carry which is long enough to make the ball advantageous for competitive play, in addition to which it has a good feel when hit and excellent durability to cracking with repeated impact.

Claims

1. A solid golf ball, comprising a solid core and a cover of one or more layers which encloses the core and has on a surface thereof numerous dimples, wherein the solid core has a JIS-C hardness at the surface thereof of 78 to 85, a JIS-C hardness at the center thereof of 60 to 68, and a difference therebetween of at least 10 but not more than 19, the cover has a Shore D hardness of 59 to 70 and has 313 to 371 dimples formed thereon, and the ball has an initial velocity of at least 76.8 m/s, a coefficient of lift (CL) when hit of at least 0.165 at a Reynolds number of 70,000 and a spin rate of 2,000 rpm, and a coefficient of drag (CD) when hit of not more than 0.230 at a Reynolds number of 180,000 and a spin rate of 2,520 rpm.

2. The solid golf ball of claim 1, wherein the solid core is composed primarily of cis-1,4-polybutadiene and includes from 1 to 30 parts by weight of styrene-butadiene rubber per 100 parts by weight of the polybutadiene.

3. The solid golf ball of claim 1, wherein the solid core has a diameter of 38.7 to 39.6 mm and the cover has a thickness of at least 1.5 mm but not more than 2.1 mm.

4. The solid golf ball of claim 1, wherein the solid core is formed of an inner/outer plurality of layers, and the outer core contains a rubber material synthesized with a rare earth catalyst or a Periodic Table group VIII metal compound catalyst, and the solid core has a deflection hardness of 3.0 to 4.0 mm.