Molding apparatus for a composite billiard ball

Claim 1

A molding apparatus for manufacturing a shock resistant transparent polymer sphere in which a disc having a symbol on each of its opposite faces is diametrically incorporated in the sphere with the center of gravity of the disc coincident with the center of gravity of the sphere, comprising, in combination: (a) a lower mold half defining an upwardly facing concave hemispherical surface, the upper exterior marginal wall of said lower mold half being cylindrical for a given vertical distance downwardly, thence extending laterally outwardly to define a flat annular upwardly facing shoulder; (b) an upper mold half defining a downwardly facing concave hemispherical surface, the lower interior wall of said upper mold half having an increased diameter portion at the lower edge of said downwardly facing concave hemispherical surface defining an interior cylindrical wall extending downwardly beyond said edge said given vertical distance and thence laterally outwardly to define a flat annular downwardly facing shoulder for seating on said upwardly facing shoulder when said exterior marginal wall is received in said interior cylindrical wall so that the upwardly facing and downwardly facing concave hemispherical surfaces are juxtaposed to define a spherical cavity, said flat upwardly facing annular shoulder and said flat downwardly facing annular shoulder including cooperating fastening means for holding the mold halves together; and, (c) a holder for said disc in the form of an annular ring having a plurality of lugs extending radially inwardly equal distances to engage the periphery of said disc at equal circumferentially spaced points to support said disc inside said ring in substantially coplanar relationship, the exterior of said ring having at least two locating pins extending radially outwardly, and a centering projection, said pins and centering projection being circumferentially spaced, the bottom-most point on said upwardly facing hemispherical surface having a hole receiving an end portion of said centering projection, and the top-most point on said downwardly facing hemispherical surface having a fill opening for introducing molding material, the diameter of said holder as measured out to the tips of said pins and the start of said end portion of said centering projection being substantially the same as the diameter of the hemispherical surfaces, whereby a shock resistant transparent polymer sphere incorporating a disc can be manufactured in a single mold material pouring operation.