Machine for the injection molding of a mixture of plasticized synthetic material

Claim 1

An injection-molding machine comprising: a plasticizing- and-mixing device having an output side; a mold provided with a plurality of injection openings distributed about said mold on different sides thereof; a plurality of complete individually adjustable and controllable injection-molding units each including an injection-molding cylinder equipped with at least one injection-molding nozzle communicating with one of said injection openings and distributed around said mold; a respective injection-molding piston reciprocating in each of said injection-molding cylinders and adapted to be subjected to pressure alternately on both sides thereof; a ring-feeding system extending around said mold and including a plurality of conduits operatively connecting said output side of said plasticizing- and-mixing device with said injectionmolding units such that said individual injection-molding cylinders and their nozzles are in operative connection with said injection openings of said mold; a single control- and-adjusting device for the control and adjustment of said plasticizing- and-mixing device and of said respective injection-molding units responsive to pressure, temperature and time; piston drive means operatively connected to each of said injection-molding pistons, the piston drive means being hydraulically controlled by said control- and-adjusting device; first valve means for each of said piston drive means actuated by said control- and-adjusting device for individually switching off a corresponding one of said injection-molding units; second valve means for closing each of said conduits to the respective injection-molding units; third valve means for closing said injection-molding nozzles of each of said plurality of injection-molding units; and pressure measuring means operatively connected to said injection-molding units and to said control- and-adjusting device for controlling all of said valve means in dependence upon pressure, time and path.