초록 ▼

Mold and method of compression molding shell half covers around a core to form golf balls. Opposed dies are pressed together such that some of the material trapped between the approaching dies is forced back into the mold to compensate for shrinkage and the remainder is forced outside of the die cav

Mold and method of compression molding shell half covers around a core to form golf balls. Opposed dies are pressed together such that some of the material trapped between the approaching dies is forced back into the mold to compensate for shrinkage and the remainder is forced outside of the die cavities where it can be drained off.

대표청구항 ▼

A process for compression molding an integral cover for two-piece golf balls, said process comprising: (a) attaching a pair of telescopically mating male and female dies to a hydraulic press for movement of the dies toward or away from one another in a substantially vertical plane, said male die hav

A process for compression molding an integral cover for two-piece golf balls, said process comprising: (a) attaching a pair of telescopically mating male and female dies to a hydraulic press for movement of the dies toward or away from one another in a substantially vertical plane, said male die having a substantially hemispherical mold cavity and an annular projection at the lip of said cavity, said female die having an oppositely facing, annular recess adapted to receive the projection and a substantially hemispherical mold cavity adapted to form a single, spherical mold cavity with said male die cavity when the dies are pushed together; (b) inserting a substantially hemispherical shell segment of thermoplastic cover material inside one of said cavities with the open end of said shell segment facing upward; (c) placing a solid core ball inside said shell segment; (d) placing another substantially hemispherical shell segment of thermoplastic cover material over said core ball with its open end facing the open end of the other shell segment; (e) operating the press to cause the dies to move toward one another and mate, with the annular projection of said male die entering the recess; (f) heating the dies to soften the cover material; (g) trapping extruded cover material from the cavities between the leading edge of the projection and an annular rim in the recess when the projection initially enters the recess; (h) continuing axial pressure on the dies to fully close the dies together and cause the leading edge of the projection to move closer to the rim and force trapped material to flow back inside the mold cavities to create an integral, spherical cover that is substantially a mirror image of the inside of the mold cavities; and, (i) draining off excess of the trapped material through a valve during mating of the dies so that the amount of extruded material that is forced back into the mold cavities is substantially only the amount needed to produce a well-shaped cover with a substantially uniform thickness. A mold for compression molding an integral cover for two-piece golf balls, said mold comprising: (a) a pair of telescopically mating male and female dies which are adapted to be attached to a hydraulic press for movement of the dies toward and away from another; (b) said male die having a substantially hemispherical mold cavity and an annular piston at the lip of said cavity; (c) said female die having a recessed area and an adjacent, substantially semispherical mold cavity, wherein the recess is adapted in size and shape to receive the piston when the dies move toward one another and said female mold cavity is adapted in size and shape to form a single, spherical mold cavity with said male cavity when the dies mate, and said female mold cavity is further adapted in size and shape to receive a hemispherical shell of cover stock material and a standard core ball for two-piece golf balls; (d) wherein said dies include means for trapping extruded cover material from the cavities when the dies are pushed together and for subsequently forcing the trapped material back into the mold cavities to form an integral, spherical cover that is substantially a mirror image of the cavities, said trapping and forcing means comprising a pressure chamber formed by a leading edge of the piston and an annular rim at the bottom of the recess; and, (e) valve means connected with said pressure chamber for draining off excess of the trapped material to insure that the only amount of trapped material transferred back into the cavities is the amount needed to produce a well-formed cover of uniform thickness.