Importance

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Abstract

An injection mold for use with a molding press has four mold levels in axially stacked relation, permitting a substantial doubling of output for a given size of press as compared with a back-to-back two level stacked mold. The mold feeder flow path extends axially from the injector head to a flow distribution block located at the center of the stacked mold block series. The centrally located distribution block is connected, in use isolation, sealed relation with the injector head, being axially displaceable therefrom in continuing sealed relation upon the opening of the mold. A drool prevention valve system, located at two of the mold interfaces, to preclude drooling of fluid plastic stock upon opening of the molds includes pressure fluid actuators for operating the valves, wherein the pressure fluid may comprise the fluid plastic stock. The valve system also includes a depressurizing valve provision, wherein, upon opening of the mold interfaces the stock distribution passages are substantially depressurized, to thereby reduce any tendency to drool. The mold includes axial adjustment means to compensate for differential variations in overall mold length within the press, due to changes in effective mold temperature.

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First Claim