Abstract: A molding apparatus has a pair of slide inserts which are laterally movable into and out of engagement with the other mold components. The lateral movement of the slide inserts is provided by a slide mechanism having a driving rack, a pair of drive pinions at either end of the driving rack, two pairs of driven racks and a plurality of slides connected to the driven racks. The driven racks of each pair are parallel and spaced from one another, engaging opposite sides of a pinion and thereby being driven in opposite directions by rotation of the pinion. The molding apparatus is more compact than conventional devices having slide inserts, eliminates the use of slide retainers, eliminates obstructions between the mold plates when the plates are separated, and can cycle faster than conventional devices.

Abstract: An apparatus for forming threaded molded parts such as closures for containers having improved means for unthreading the formed part from the mold core. The apparatus includes a cavity part and a core part, the cavity part being rotatable relative to the core part, such that simultaneous rotation of the cavity and opening of the mold results in unthreading of the part from the core. The mold cavity is rotationally coupled to a mold cavity rotator which is preferably driven by means of a rack. The rotation of the mold cavity is timed with the mold opening step such that the threaded part is unthreaded from the core as the mold plates are separated.

Abstract: An apparatus and method for ejecting threaded injection molded articles from a mold core by simultaneous application of rotational and translational force. The apparatus has a stripper ring which is rotatable about and movable along its axis. A driver rotates a stripper ring rotator in response to input from a machine ejector rod. Input from the machine ejector rod is transferred to the driver by a helically splined spindle which is axially movable relative to the driver and which engages a corresponding helically splined bore in the stripper ring rotator. Rotation of the stripper ring rotator is transferred to the stripper ring by meshing pinions. The stripper ring rotator also has a gear which meshes with corresponding teeth in a transversely extending rack to cause movement of the rack. Cams are secured to the rack and act against cam followers connected to the stripper ring to translate transverse movement of the rack into axial movement of the stripper ring.

Abstract: A molded cap for sealing a container, and having a core-profiled internal skirt portion is injection molded within a seamless annular cavity mold, wherein segmentation of the interior core die portion bearing the internal form such as a screw thread form for the inside of the cap skirt, permits its inward withdrawal clear of the cap after completion of the injection cycle. Due to the seamless mold cavity the cap has no externally visible mold witness lines along its skirt. The molded cap contracts radially as it cools within the mold, permitting molded parts and decorative features that are on or in the skirt face to withdraw radially inwardly from the mold surfaces, such that the cap can be ejected clear from the mold without damage to fine detailed or hang-up on undercuts into the mold skirt face.