Collapsible mold core

A collapsible mold core which comprises:

• an inner core member defining opposed first and second ends, said inner core member tapering transversely to a reduced diameter from said first end to the second end, and the plurality of outer core members attached to the lateral exterior of said inner core member in longitudinally slidable relation thereto between first and second positions, said outer core members defining first ends and second ends corresponding in position to the first and second ends of the inner core member, said outer core members tapering inwardly in transverse dimension from their second ends to their first ends to provide an opposite taper to that of the inner core member, the outer side walls of said collapsible mold core defining a generally cylindrical shape in said first sliding position;
• said longitudinally slidable relation between the inner and outer core members being provided by key and keyway means;
• said outer core members including first outer core members defining a convex, arcuate outer surface, and converging inner surfaces connected at their edges to lateral edges of the outer surface and defining acute angles thereto, said first outer core members being spaced from each other in the first sliding position, and second outer core members positioned between said first outer core members, said second outer core members being of generally triangular cross section and defining a pair of inwardly-angled outer surfaces positioned in sliding relation with inner surfaces of adjacent first outer core members, said second outer core members also each defining an arcuate, concave inner surface positioned in sliding relation with said inner core, said inwardly-angled outer surfaces defining acute angles with the arcuate inner surface, to permit molding of an object about the mold core in the first sliding position, and removal of the object from the core in the second sliding position, said inner core member and outer core members being substantially free of internal open spaces between them in the first sliding position, longitudinally movable stripper ring means connected to said first outer core members, and cooling liquid conduit means carried by said stripper ring means and communicating through the interior of at least some of said outer core members to facilitate cooling of said mold core during operation.

A collapsible mold core which comprises:

• an inner core member defining opposed first and second ends, said inner core member of the shape of a truncated cone, tapering transversely to a reduced diameter from said first end to the second end, and the plurality of outer core members attached to the lateral exterior of said inner core member in longitudinally slidable relation thereto between first and second positions, said outer core members defining first ends and second ends corresponding in position to the first and second ends of the inner core member, said outer core members tapering inwardly in transverse dimension from their second ends to their first ends to provide an opposite taper to that of the inner core member, the outer side walls of said collapsible mold core defining a generally cylindrical shape in said first sliding position;
• said longitudinally slidable relation between the inner and ouer core members being provided by key and keyway means;
• said outer core members including first outer core members defining a convex, arcuate outer surface, and converging inner surfaces connected at their edges to lateral edges of the outer surface and defining acute angles thereto, said first outer core members being spaced from each other in the first sliding position, and second outer core members positioned between said first outer core members, said second outer core members being of generally triangular cross section and defining a pair of inwardly-angled outer surfaces positioned in sliding relation with inner surfaces of adjacent first outer core members, said second outer core members also each defining an arcuate, concave inner surface positioned in sliding relation with said inner core, said inwardly-angled outer surfaces defining acute angles with the arcuate inner surface, to permit molding of an object about the mold core in the first sliding position, and removal of the object from the core in the second sliding position, said inner core member and outer core members being substantially free of internal open spaces between them in the first sliding position.