Mold for manufacturing golf balls and golf balls

• US 20090023520A1
• Filed: 07/19/2008
• Published: 01/22/2009
• Est. Priority Date: 07/20/2007
• Status: Active Grant

• Current Assignee: Mizuno Corporation
• Original Assignee: Mizuno Corporation
• Inventors: Michishita, Masahiro, Ninomiya, Norikazu, Fujikawa, Yoshihiro
• Granted Patent: US 8,287,261 B2
• Time in Patent Office: Days
• US Class Current: 473/383
• CPC Class Codes: A63B 37/0003 Golf balls
• CPC Class Codes: A63B 37/0004 Surface depressions or protrusions
• CPC Class Codes: A63B 45/00 Apparatus or methods for manufacturing balls working of plastics or substances in a plastic state B29
• CPC Class Codes: B29C 2045/0034 Mould parting lines
• CPC Class Codes: B29C 45/0025 Preventing defects on the moulded article, e.g. weld lines, shrinkage marks preventing defects on the preformed parts or layers B29C45/14836
• CPC Class Codes: B29C 45/372 provided with means for marking or patterning, e.g. numbering articles

Abstract

The present invention relates to a mold having a parting line along dimples which allows manufacturing of golf balls free from burrs, and to golf balls manufactured using such a mold. The mold of the present invention is provided with a spherical cavity inside thereof; and an upper mold and a lower mold separable from each other, wherein a plurality of convex portions for forming dimples is provided in the inner surface of the cavity, at least one of the plurality of convex portions lies over the equator of the cavity, a parting line, which corresponds to the boundary between the upper mold and the lower mold, extends along the inner surface of the cavity, the parting line comprises first lines extending along the peripheries of the convex portions lying over the equator and second lines connecting the first lines, and the first line is disposed apart from the periphery by a distance of 0.1 to 0.5 mm.

Claims

1. A mold for manufacturing golf balls, comprising:

an upper mold and a lower mold separable from each other having a spherical cavity inside thereof;

wherein a plurality of convex portions for forming dimples are provided in the inner surface of the cavity;

at least one of the plurality of convex portions lies over the equator of the cavity;

a parting line, which corresponds to the boundary between the upper mold and the lower mold, extends along the inner surface of the cavity,

the parting line comprises first lines extending along the peripheries of the convex portions lying over the equator and second lines connecting the first lines, and

the first line is situated apart from the periphery by a distance of 0.1 to 0.5 mm.

4. A mold for manufacturing golf balls according to any one of claims 1 to 3, wherein at least one concave portion is provided in each of the surfaces where the upper mold and the lower mold come into contact,

the mold comprises at least one convex member placed in the space formed by the corresponding concave portions in the upper mold and the lower mold, fixed to either concave portion, and has convex portion lying over the equator on the surface facing inside the cavity, and

in the periphery of the convex member on the surface facing the inside the cavity, a portion that is not fixed to the concave portion coincides with the first line.

5. A mold for manufacturing golf balls according to any one of claims 1 to 3, wherein a concave portion is provided in each of the surfaces where the upper mold and the lower mold come into contact,

the mold comprises at least one convex member placed in the space formed by the corresponding concave portions in the upper mold and the lower mold, fixed to either concave portion, and has convex portion lying over the equator on the surface facing inside the cavity, and

in the convex member, the surface facing the inside of the cavity comprises a convex surface forming the convex portion and a flat surface formed in ring-like shape around the convex surface, and

the flat surface is coincide with the inner surface of the mold and its width corresponds to the distance between the first line and the periphery of the convex portion.

6. A golf ball obtained using any one of the molds defined in claims 1 to 3.

7. A golf ball obtained using any one of the molds defined in claim 4.

8. A golf ball obtained using any one of the molds defined in claim 5.

2. A mold for manufacturing golf balls, comprising:

an upper mold and a lower mold separable from each other having a spherical cavity inside thereof;

wherein a plurality of convex portions for forming dimples are provided in the inner surface of the cavity;

at least one of the plurality of convex portions lies over the equator of the cavity;

a parting line, which corresponds to the boundary between the upper mold and the lower mold, extends along the inner surface of the cavity,

the parting line comprises first lines extending along the peripheries of the convex portions lying over the equator, and second lines connecting the first lines, and

the first line is situated on a portion of the periphery at the location most far from the equator on the periphery and/or in the vicinity thereof and is formed apart from the periphery by a distance of 0.1 to 0.5 mm in the rest portion.

3. A mold for manufacturing golf balls, comprising:

an upper mold and a lower mold separable from each other having a spherical cavity inside thereof;

wherein a plurality of convex portions for forming dimples are provided in the inner surface of the cavity;

at least one of the plurality of convex portions lies over the equator of the cavity;

a parting line, which corresponds to the boundary between the upper mold and the lower mold, extends along the inner surface of the cavity,

the parting line comprises first lines extending along the peripheries of the convex portions lying over the equator, and second lines connecting the first lines, and

the first line is situated on a portion of the periphery at the location between the portion most far from the equator on the periphery and/or in the vicinity thereof and the portion connected to one of the second lines, and is formed apart from the periphery by a distance of 0.1 to 0.5 mm in the rest portion.