Apparatus and method for molding golf balls
The present invention is directed to a mold and method for forming a golf ball with at least a core. The mold and method comprise or use members with projections for forming multiple dimples on the core. The members can be retractable pins or sleeves or vent pins. In the case of the retractable pins, sets of pins with multiple dimple projections on the ends thereof are used to center the golf ball core within the mold. The members can have circular or non-circular cross-sections so that the dimple-forming projections can conform to any dimple pattern.
1. A mold for forming a golf ball having a core, the mold comprising:
(a) a first mold plate having at least one first hemispherical cavity and a first set of members for contacting a first side of the core, wherein the first set of members comprise at least two, separate pins each comprising at least two projections at a free end for contacting the core;
(b) a second mold plate having at least one second hemispherical cavity and a second set of members for contacting a second side of the core, wherein the second set of members comprise at least two, separate pins each comprising at least two projections at a free end for contacting the core,
wherein upon mating the first mold plate with the second mold plate, each first hemispherical cavity and each second hemispherical cavity form a molding cavity for receiving the core, wherein the molding cavity defines an outer spherical surface,
wherein
each pin of the first and second members is movable between an extended position where the at least two projections are spaced from the outer spherical surface and contact the core, and a retracted position where the projections form a portion of the outer spherical surface of the cavity, and wherein each pin of the first set of members is unaligned with each pin of the second set of members.
2. The mold of claim 1 , wherein the projections are hemispherical in shape.
3. The mold of claim 1 , wherein each pin of the first set of members is 180° out of phase with each pin of the second set of members.
4. The mold of claim 1 , wherein each set of members comprises at least five projections.
5. The mold of claim 1 , wherein the projections on each pin are spaced from one another.
6. The mold of claim 1 , wherein the projections on each pin are spaced from the perimeter of the member.
7. The mold of claim 1 , further comprising at least one runner terminating in at least one gate for flowing a molten material into the cavity; and an injection unit for injecting the molten material through each runner into each cavity.
8. A mold for forming a golf ball having a core, the mold comprising:
(a) at least one internal molding cavity for receiving the core; and
(b) at least one pin having a first end, a spaced, second end, and at least two projections at the second end for contacting the core, each pin has a non-circular cross sectional shape between the first end and the second end, and wherein the cross-sectional shape comprises at least two substantially circular portions.
9. The mold of claim 8 , wherein the cross-sectional shape comprises four substantially circular portions arranged in a line triangle, or rectangle.
10. The mold of claim 8 , wherein the cross-sectional shape comprises three substantially circular portions arranged in a line or triangle.
11. The mold of claim 8 , further comprising at least one first pin and at least one second pin diametrically opposed to the first pin.
12. The mold of claim 8 , wherein the at least one molding cavity further defines an outer spherical surface, and the pins are movable between an extended position where the projections are spaced from the outer spherical surface and a retracted position where the projections form a portion of the outer spherical surface.
13. The mold of claim 8 , wherein each pin projection has a hemispherical shape with an apex and the apex of each pin is at a different vertical position than the remaining apexes.
14. The mold of claim 8 , further comprising at least one runner terminating in at least one gate for flowing a molten material into the at least one molding cavity; and an injection unit for injecting the molten material through each runner into each cavity.
15. A mold for forming a golf ball having at least a core, the mold comprising:
(a) at least one internal molding cavity for receiving the core, the cavity defining an outer spherical surface; and
(b) at least one stationary member associated with each cavity, each comprising at least two projections at a free end where the projections form a portion of the outer spherical surface of the cavity and a non-circular cross-section between the free end and a spaced end.
16. The mold of claim 15 , wherein the non-circular cross-section comprises at least two substantially circular portions.
17. The mold of claim 15 , wherein the at least one stationary member comprises at least three projections.