Method for molding composite metal-elastomer wheels

Abstract

Method for molding a composite metal-elastomer styled wheel in which a middle mold part consists of a metal wheel disc and rim subassembly. A base mold part seats against the outboard face of the metal wheel in the closed condition of the mold and has a mold cavity surface to provide an ornamental configuration for the outboard face of the plastic body of the composite wheel. There is a clamp which includes a funnel adapted for registry with a liquid reaction mixture injection nozzle coupled with injecting mixing apparatus. The funnel has a nozzle passage registering with a pour opening in the disc in the closed condition of the mold. A sprue pin is affixed to the base mold part in juxtaposed relation to the disc pour opening and cooperates with the margin of the pour opening to define a restricted access opening to the mold cavity during the injection pour of the urethane reaction mixture. The sprue pin is operable to restrict back-flow of the reaction material during gelation of the same in the cure cycle. The sprue pin and disc in the vicinity of the pour opening define a zone of weakness in the cured urethane reaction mixture operable to induce fracture in the zone upon separation of the base mold part from the middle part to thereby cause cleavage of the urethane reaction material adjacent the inboard surface of the middle mold part.