Golf ball

• US 7,083,533 B2
• Filed: 10/16/2002
• Issued: 08/01/2006
• Est. Priority Date: 10/26/2001
• Status: Active Grant

• Current Assignee: Bridgestone Sports Co Limited (Bridgestone Corporation)
• Original Assignee: Bridgestone Sports Co Limited (Bridgestone Corporation)
• Inventors: Maehara, Kazuto, Kasahima, Atsuki, Takesue, Rinya
• Primary Examiner(s): Blau, Stephen
• Assistant Examiner(s): HUNTER, ALVIN A
• Application Number:
  US10/270,491
• Publication Number:
  US 20030096663A1
• Time in Patent Office: 1,385 Days
• Field of Search: 473351-383
• US Class Current: 473/378
• CPC Class Codes: A63B 37/0003 Golf balls
• CPC Class Codes: A63B 37/0004 Surface depressions or protrusions
• CPC Class Codes: A63B 37/0017 Specified total dimple volume
• 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 37/0021 Occupation ratio, i.e. percentage surface occupied by dimples
• CPC Class Codes: A63B 37/0031 Hardness
• CPC Class Codes: A63B 37/0033 Thickness
• CPC Class Codes: A63B 37/0035 Density; Specific gravity
• CPC Class Codes: A63B 37/0043 Hardness
• CPC Class Codes: A63B 37/0065 Deflection or compression
• CPC Class Codes: A63B 37/0066 Density; Specific gravity
• CPC Class Codes: A63B 37/0075 Three piece balls, i.e. cover, intermediate layer and core
• CPC Class Codes: A63B 37/0078 Coefficient of restitution
• CPC Class Codes: A63B 37/008 Diameter
• CPC Class Codes: A63B 37/0084 Initial velocity
• CPC Class Codes: A63B 37/0087 Deflection or compression
• CPC Class Codes: A63B 37/0089 Coefficient of drag
• CPC Class Codes: A63B 37/009 Coefficient of lift
• CPC Class Codes: A63B 37/0092 : Hardness distribution amongst different ball layers
• CPC Class Codes: A63B 37/0096 : Spin rate
• CPC Class Codes: A63B 37/12 : Special coverings , i.e. outer layer material balls with finger holes A63B37/0001, golf ball covers A63B37/0023

Abstract

In a golf ball comprising an elastic solid core, a mantle layer, and a resin cover having a plurality of dimples, the difference in Shore D hardness between the cover and the mantle layer is at most 10, and the dimples have a total volume of 280–350 mm³. This combination of features provides the golf ball with an excellent balance of rebound, spin and feel, and an outstanding total distance.

Claims

1. A golf ball comprising an elastic solid core, a resin cover which encloses the core and has a plurality of surface dimples, and a mantle layer situated between the core and the cover;

wherein

the cover and the mantle layer have a difference in Shore D hardness therebetween of at most 10, and

the dimples have a total volume of 280 to 350 mm³,

wherein the ball, when hit, has a coefficient of lift CL and a coefficient of drag CD such that the ratio CL/CD is 0.676 to 0.796 at a Reynolds number of 200,000 and a spin rate of 2,700 rpm, 0.813 to 0.933 at a Reynolds number of 120,000 and a spin rate of 2,400 rpm. and 0.856 to 0.976 at a Reynolds number of 80,000 and a spin rate of 2,000 rpm.

2. The golf ball of claim 1, wherein the dimples have a diameter of 2.0 to 5.0 mm and the total number thereof is from 300 to 550, wherein 300 to 400 dimples which have the diameter of at least 3.7 mm are included.

3. The golf ball of claim 1, wherein the mantle layer has a Shore D hardness of 56 to 68, and the cover has a Shore D hardness of 51 to 62.

4. The golf ball of claim 1, wherein the mantle layer has a Shore D hardness of 56 to 66.

5. The golf ball of claim 1, wherein the cover has a Shore D hardness of 54 to 62.

6. The golf ball of claim 1, wherein the dimples have a surface coverage of at least 75%, based on the total surface of the ball.

7. A golf ball comprising an elastic solid core, a resin cover which encloses the core and has a plurality of surface dimples, and a mantle layer situated between the core and the cover;

wherein

the elastic solid core undergoes a deflection of 2.8 to 4.2 mm when subjected to a load of 1,275 N (130 kgf) from an initial load of 98 N (10 kgf),

the cover is composed primarily of a polyurethane elastomer,

the mantle layer is composed of a composition prepared by the addition of an olefin elastomer to an ionomer resin,

the cover is set to a Shore D hardness which is from 1 to 10 units lower than the Shore D hardness of the mantle layer,

the dimples have a total volume of 280 to 350 mm³, and

the dimples situated near the ball'"'"'s equator which include dimples intersected with the equator are formed to a depth 5 to 60 μ

m greater than the dimples of the same diameter in other areas.

8. The golf ball of claim 7, which has a coefficient of restitution of 0.77 to 0.83 at an incident velocity of 43 m/s.

9. The golf ball of claim 7, wherein the olefin elastomer includes olefin-based block copolymers, olefin-based random copolymers, and dynamically crosslinked thermoplastic elastomers.

10. The golf ball of claim 7, wherein an amount of a projection of the dimples which cross the equator and project out into the other hemisphere is 10 to 45% of the dimple diameter.