Husky Injection Molding Systems Limited

Graham Packaging Pet Technologies Inc.

John B Wright

Robert D Schad

Thomas E Nahill

Gregory A Ritz

L Robert Deardurff

Richard A Farquharson

George Knapik

Michael A Rymer

A method and apparatus for compression molding plastic articles include a plurality of tools mounted in opposed pairs with the tools of each pair including opposed first and second actuators that define a mold cavity in which a charge of plastic is compression molded. The tooling is preferably carried by a rotary turret so that first and second actuators of each tooling pair are moveable relative to each other between an open position permitting formed articles to be removed from the tooling and to receive fresh charges of plastic, and a closed position to compression mold the charges of plastic.

Method and apparatus for compression molding plastic articles

An injection moulding apparatus includes a manifold having a channel receiving an injection of molten polymer and delivering the molten polymer to a nozzle assembly. The nozzle includes a nozzle gate delivering the molten polymer to a mould. A valve gate drop assembly has a valve pin extending from a valve pin cylinder which passes through an eccentric bushing in the manifold. The valve pin extends into the nozzle assembly and terminates at the nozzle gate. The valve pin is aligned with the nozzle gate and is adapted for control of flow of molten polymer through the nozzle gate by movement into and away from the nozzle gate. The movement of the valve pin is controlled by the valve pin cylinder. During operation, the manifold can undergo a change in position relative to the positions of the valve pin cylinder and nozzle assembly as a result of thermal expansion and contraction of the manifold. The eccentric bushing in the manifold rotates on change of position of the manifold generally to maintain alignment of the valve pin with the nozzle gate and reduce deflection of the valve pin caused by change of position of the manifold.

Reduction in deflection of valve pin in injection moulding apparatus

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. When the limit of the lost-motion travel is reached, the stripper plates are slowly lifted off their adjoining mold portions to detach the molded articles from the cores.

Stripper mechanism for injection mold

Growing community of inventors

Port McNicoll, Canada

John B Wright