Hpm Corporation

Koehring Company

Donald W Staiger

Gary L Myers

William T Flickinger

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

Access to mold halves disposed on and between opposed stationary and movable platens of a molding machine is facilitated by releasing and at least partially retracting, from the zone between the platens, at least one of a plurality of tie rods extending therebetween. A tie rod is at least partially removed by (1) slidingly translating the movable platen along the tie rods toward the stationary platen, (2) releasing one tie rod from connection with the stationary platen and connecting it to the movable platen, and then (3) slidingly translating the movable platen away from the stationary platen along tie rods remaining connected thereto, to at least partially retract the released tie rod from between the stationary and movable platens.

Growing community of inventors

Mount Gilead, OH, United States of America

Donald W Staiger