Abstract: An injection-molding machine has a fixed and a movable outer platen bracketing a movable intermediate platen, the latter having a runner system conducted via an extensible or flexible conduit to a source of molten plastic material to be injected into cavities defined by respective pairs of mold portions supported by the three platens, the cavities being formed in part by cores carried on the outer mold portions. A stripper plate inserted between each pair of mold portions is articulated via a spring-loaded lost-motion link to a respective eccentric pin on a pinion which is rotatably mounted on the intermediate platen and meshes with a pair of racks respectively secured to the two outer platens; this linkage is duplicated on opposite sides of the mold. In an initial phase of a mold-opening stroke, the stripper plates move outwardly under spring pressure while remaining in contact with their respective outer mold portions whose cores still retain the freshly molded articles.

Abstract: An injection gate of a mold cavity comprises an elongate valve rod which passes axially through a flow channel for molten plastic material and is guided in an extension of a thin-walled steel cylinder open at its opposite end toward an adjoining manifold plate. The rod extremity remote from the gate is secured to a tubular neck of a piston inside the cylinder whose stroke length is a fraction of the axial height of the cylinder's interior, a clearance around this neck providing space for drooling plastic while the length of the neck and of the peripheral cylinder wall serves for thermally insulating the manifold plate from the flow channel.