Plastic injection molding machine

Abstract

The machine includes a hydraulically operated rotatable and axially displaceable plasticizer and injection screw, and has a frame including a traverse or supporting bridge member. An injection cylinder is secured to one side of the traverse and a plasticizing cylinder, guiding the screw, is secured to the opposite side of the traverse. A hollow, non-rotating piston is guided in the injection cylinder, and a hydromotor is fixedly connected with the injection piston. The hydromotor has a drive shaft extending coaxially through the injection piston and coupled coaxially to the plasticizer and injection screw. The hydromotor, its drive shaft, the injection piston and the plasticizing screw thus form an axially movable coaxial unit mounted for limited axial movement on beams secured on the mold-carrier plate at the nozzle side of the mold. A part of the drive shaft extending out of the injection piston for connection to the screw is preferably sealed in the injection cylinder so that no pressure medium can penetrate from the injection cylinder into the cylinder chamber into which plastic scrap material extends during the return stroke of the screw.

Dependencies are inferred from the claim text.