Multi-layer golf ball having inner covers with non-planar parting lines

Abstract

The invention comprises a golf ball. The golf ball is formed with a core, at least one intermediate layer, and a cover. The intermediate layer has a non-planar parting line. The molds used to form the intermediate layer have non-planar mating surfaces. The non-planar mating surfaces of the molds mesh, and when the intermediate layer is formed therein, the intermediate layer has a non-planar parting line thereon. If compression molding is used, hemispherical layer blanks may be pre-formed in the shape of the mold halves. To form the intermediate layer, the two blanks are compression molded together. If injection molding is used, a core is placed inside a mold chamber and layer material is injected into the mold chamber to form the intermediate layer about the core. If reaction injection molding is used, two or more reactive precursors are mixed and injected into the mold cavity, and they react to form the intermediate layer. Optional outer layers and a cover are molded on the intermediate layer to form a finished ball.

1 . A method of injection molding an outer layer surrounding a golf ball subassembly comprising the steps of:
 providing a mold made from two mold-halves with a non-planar parting line wherein the mold comprises a first set of vents and a second set of vents, and wherein the first set of vents is located proximate to the peaks of the parting line and the second set of vents is located proximate to the troughs of the parting line,   locating the mold around the golf ball assembly,   injecting molten material into a polar gate in each mold-half, and   allowing the molten material to meet proximate the parting line to form the outer layer.   
     
     
         2 . The method of  claim 1 , wherein the first set of vents is located substantially on the peaks of the parting line and the second set of vents is located substantially on the troughs of the parting line. 
     
     
         3 . The method of  claim 1 , wherein at least one of the vents is an elongated vent.