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 actuator carriage for a multi-level injection molding apparatus having mold core and mold cavity support plates, tie bars supporting a moveable platen and having stripper mechanisms associated with mold cores mounted to the mold core support plates. The stripper mechanisms are displaced relative to the mold cores by lever arms having cam surfaces engaging actuators carried by the actuator carriage. Each actuator carriage includes a support bar extending generally transversely relative to the tie bars with at least one of the actuators being mounted on the support bar. At least one connector bar is rigidly secured to the support bar and a respective of the mold cavity support plates. The connector bar maintains the support bar at a fixed distance from the mold cavity support plate. The support bar is moveable along at least one of the tie bars and has a lateral restraining device limiting lateral movement of the support bar toward respective of the tie bars.

Abstract: A melt ducting arrangement for an injection molding system having a heated nozzle, a valve pin axially slideable in the heated nozzle and a guide bushing for the valve pin which extends into a manifold and of the heated nozzle. The melt ducting arrangement includes a groove in the heated nozzle extending at least part way around the guide bushing. A melt passage extends between the groove and a melt passage in a manifold. The guide bushing has a hole extending generally axially therethrough. The hole has a narrower diameter portion facing away from the heated nozzle and a wider diameter portion facing into the heated nozzle. The narrower diameter portion slideably receives and guides a valve pin. The wider diameter portion provides space to receive melt between the valve pin and the bushing. Radially spaced openings extend through the bushing and register with the groove and to provide a melt conduit between the bushing and the wider diameter portion of the hole.

Abstract: This invention relates to sealing and support bushings which are located between the manifold and the mold back plate to encircle each valve pin in a multi-cavity valve gated injection molding system. Each bushing is bolted through the manifold to a respective heated nozzle with central bores in alignment to receive the valve pin therethrough. The bushing has an outer flanged portion which extends to contact the mold back plate and forms a leakage containment chamber between them. Thus, the bushings retain the manifold in place, seal against substantial melt leakage around the reciprocating valve pins and collect any melt which does escape to prevent it entering the insulative air space between the hot manifold and the cooled mold back plate. Location of the bushing between the manifold and the mold back plate also enables the use of a standard manifold having longitudinal and transverse bores without requiring diagonal bores.