Mold for golf ball

• US 20040041297A1
• Filed: 08/19/2003
• Published: 03/04/2004
• Est. Priority Date: 09/03/2002
• Status: Active Grant

• Current Assignee: Sumitomo Rubber Industries Limited
• Original Assignee: SRI Sports Limited (Sumitomo Rubber Industries Limited)
• Inventors: Endo, Seiichiro, Sajima, Takahiro
• Granted Patent: US 7,150,618 B2
• Time in Patent Office: Days
• US Class Current: 264/161
• CPC Class Codes: B29C 2043/022 having locally depressed lines, e.g. hinges
• CPC Class Codes: B29C 2043/023 having a plurality of grooves
• CPC Class Codes: B29C 37/02 Deburring or deflashing thermal deburring in general B23D79/005
• CPC Class Codes: B29C 43/021 characterised by the shape of the surface
• CPC Class Codes: B29C 43/027 having an axis of symmetry B29C43/102 takes precedence
• CPC Class Codes: B29L 2031/54 Balls
• CPC Class Codes: B29L 2031/545 Football balls

Abstract

A mold for a golf ball comprises an upper portion (1) and a lower portion (3). A large number of projections (7) for dimple formation are provided on a cavity surface (5) of each of the upper portion (1) and the lower portion (3). A parting surface (8) of the upper portion (1) and the lower portion (3) has a concavo-convex shape. The parting surface (8) includes a first horizontal plane (13), a second horizontal plane (15) and an inclined surface (17). Circumferential central angles φ of the first horizontal plane (13) and the second horizontal plane (15) are 55 degrees or less. A total value Σφ of the circumferential central angles φ is 30 degrees to 330 degrees. An inclination angle α of the inclined surface (17) to a horizontal direction is 10 degrees to 60 degrees. A central angle θ between the horizontal planes (13) and (15) and an equator (E) is 1 degree to 8 degrees. A boundary corner portion of the horizontal planes (13) and (15) and the inclined surface (17) is subjected to rounding.

Claims

1. A mold for a golf ball comprising upper and lower portions having a large number of projections for dimple formation on cavity surfaces thereof,

wherein parts of the projections cross an equator,

each of the upper and lower portions has a plurality of horizontal planes and a plurality of inclined surfaces on a parting surface,

a total value Σ

φ

of circumferential central angles φ

of the horizontal planes is 30 degrees to 330 degrees, and

an inclination angle α

of the inclined surface to a horizontal direction is 10 degrees to 60 degrees.

2. The mold according to claim 1, wherein each of the circumferential central angles φ

of the horizontal planes is 55 degrees or less.

3. The mold according to claim 1, wherein a central angle θ

between the horizontal plane and the equator is 1 degree to 8 degrees.

4. The mold according to claim 1, wherein a boundary corner portion between the horizontal plane and the inclined surface is subjected to rounding.

5. A method of manufacturing a golf ball, comprising the steps of:

putting a material in a mold which includes upper and lower portions having a large number of projections on cavity surfaces thereof, each of the upper and lower portions having a plurality of horizontal planes and a plurality of inclined surfaces on a parting surface thereof, a sum Σ

φ

of circumferential central angles φ

of the horizontal planes being 30 degrees to 330 degrees, and an inclination angle α

of the inclined surface to a horizontal direction being 10 degrees to 60 degrees;

forming a dimple having a shape obtained by inverting a shape of the projection through the projection; and

grinding and removing a spew formed by a material leaking out at the parting surface.