Hpm Corporation

Koehring Company

William T Flickinger

Donald W Staiger

Thomas G Bishop

An injection molding machine having a dual tonnage traversing cylinder whereby extended stroke mold breakaway force may be exerted by the traversing cylinder unit before it begins its higher speed traversing movement to completely open the mold. The traversing cylinder comprises a normal length piston received within the cylinder barrel and bolted at one end to the moveable platen. The effective working area of the pressure face for this piston during the retraction stroke is such that low force, high speed retraction of the mold section connected to the moveable platen may be achieved. Also disposed within the barrel is a breakaway piston, which may be annular in shape and disposed concentrically with respect to the fast traverse piston and positioned such that it will abut an annular shoulder on the fast traverse piston throughout the retraction stroke of the breakaway piston. The effective working area of the pressure face for the breakaway piston is considerably larger than that of the fast transverse piston so that much greater breakaway force can be exerted on the moveable platen during the early stage of mold separation after the initial, short distance breakaway force is exerted by the main cylinders.

Method for opening die sections

Injection molding machine having dual tonnage traversing cylinder

A screw for injection molding of synthetic resinous material having a tendency to abrade and score the injection molding apparatus is provided along a substantial length of the feed section with a substantially undercut screw flight. An average particle of synthetic resinous feed stock material may pass between the undercut screw flights and a cooperating barrel without squashing. The undercut screw flights are effective to provide a controlled feed pressure for the particulate material entering the downstream portion of the screw.

Growing community of inventors

Marion, OH, United States of America

William T Flickinger