Abstract: A centering arrangement for controlling relative movement between a series of mold support plates in a stack mold having three or more levels. The centering arrangement uses a plurality of centering devices which are substantially identical, each spanning two mold levels and being connected to three adjacent mold support plates. Each centering device has a shaft generally parallel to an axis of the mold and having an intermediate portion journalled in an intermediate connector to allow rotational movement about a shaft axis, but to restrain relative axial movement between the shaft and the intermediate connector. Helical splines extend from the intermediate portion toward opposite ends of the shaft in oppositely twisting helices. End connectors having cooperating splines engage the splined portions of the shaft and connect the centering device to the outermost of the mold plates to which it is connected.

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: The invention provides a motion transfer mechanism for transferring motion between a first and second component, the mechanism comprising an elongate track mounted to the first component, the track having a polar axis and an external actuation surface along a portion of the length of the track, the track having at least one portion of the actuation surface inclined at a predetermined spiral angle about the polar axis; track riding device, mounted to the second component in guided contacting relation with the actuation surface, for longitudinal displacement relative to the actuation surface, and for predetermined rotational displacement in response to the longitudinal displacement, the track riding device comprising: an actuating surface follower mounted within a rider housing; and biasing device disposed between the follower and the housing for resiliently urging the follower into continuous engagement with the actuation surface; track mounting device for mounting the track to the first component in predeterm

Abstract: A valve pin actuator for a valve-gated injection molding system. The actuator has an annular piston mounted in and movable back and forth along an annular bore along a pin axis. The piston extends radially outwardly of any melt passages fluidly communicating with an injection molding nozzle. A tie bar extends substantially diametrically across the piston for securing an upper end of a valve pin extending into the injection molding nozzle to cause the valve pin to move axially with the piston thereby moving the valve pin between open and shut positions.

Abstract: A method and apparatus for distributing melt through three level stack molds. According to the method a crossover manifold is provided between adjacent mold levels of the stack mold, the crossover manifold having a plenum generally coaxial with a mold axis. Melt is introduced into the plenum through an inlet passage and distributed from the plenum to respective nozzle arrays through a separate outlet conduit associated with each mold level. The apparatus includes a crossover manifold mounted between first and second mold levels and having a plenum generally coaxial with the mold axis. An inlet conduit fluidly communicates with the plenum and an injection head to provide a melt path from the injection head into the plenum. A separate outlet conduit is provided for each mold level.

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: A modular injection mold assembly having a core part with an ejector box side securable to a mold base and a core side presenting a first mold face on an outer surface. The assembly further includes a cavity part presenting a second mold face mountable opposite the first mold face. An ejector assembly is mounted within the ejector box side of the core part and has a base member and at least one ejector pin extending from the base member through the core. The ejector assembly is movable relative to the core between a retracted position in which an outer end of each of the ejector pins forms part of the first mold face and an extended position wherein the outer end of each of the ejector pins protrudes from the first mold face. The base member of the ejector assembly further includes a cam follower for causing the ejector assembly to move from the retracted position to the extended position in response to input from a cam mounted to either the mold base or the core.

Abstract: The nozzle tip of an injection mold, which admits plastic at high injection pressures and temperatures to the gate of the mold, is locked on its seat within the nozzle housing by way of an axially elongated bridging key arrangement, to lock the nozzle tip to the nozzle housing and preclude backing-off movement of the nozzle tip into the gate. This prevents the nozzle tip from moving to block or partially block-off the gate. By securely locking the nozzle tip, potential damage to the mold gate is avoided. A singular keyway comprising aligned keyway portions may be provided, in mutual radial facing relation, to receive an elongated key therein. A differentiated nozzle tip locking embodiment provides two annular arrays of complementary keyway halves in mutual facing relation, forming potential insertion keyways in differentiated matching relation to provide one almost perfect match-up between two halves of a keyway, for insertion of a tubular spring pin as a key in locking relation therein.

Abstract: A multi-level stacked mold having at least two and as many as four levels of cavities has a stock distribution mold block centred axially of the stacked mold blocks, the axially extending stock inlet passage to the distribution block connecting with radially off-set stock transfer passages that cross the axially openable mold block interfaces, into the adjoining mold blocks. These openable stock transfer passages, are each provided at their respective, non-encapsulated, radially off-set, opening interfaces with a valveless anti-drool arrangement. The mold flow passage system is subject to continual, extreme, thermal cycling and cyclical mechanical loading, during the repeated opening-and-closing cycles of the mold. Each separable anti-drool sealing interface has a relatively axially displaceable portion extending to bridge the initial gap opening between adjacent mold blocks and serving as an expansible piston means.