1. Field of the Invention
The invention is directed to an apparatus for injection molding of plastics material according to the injection process which operates with a nozzle attachable to an injection tool or an injection mold, wherein the nozzle enables selectively the sole injection of plastics melt, the simultaneous injection of a plastic melt and of a gaseous or liquid medium as well as the sole injection of a medium into the mold cavity, and wherein the melt is suppliable from the extruder cylinder of the extruder around a nozzle torpedo or spreader to the nozzle mouth and the medium is introducible into the nozzle so as to be spaced from the nozzle mouth.
2. Description of the Prior Art
In known devices of this type it is disadvantageous that the melt flow of the plastics material to the nozzle must be interrupted by external control of an associated cutoff, if it is important that exclusively for instance gas is injected through this nozzle into the mold cavity of the injection molding die or the injection mold, which mold was previously possibly supplied only with plastics material or with a mixture of plastics material and gas.
The external control of a cutoff for the melt flow provided results in this known device is a relatively high construction cost, because apart from the cutoff itself hydraulic cylinders with control devices must be additionally provided at the injection molding machine. Difficulties result in the known embodiments however also if it is necessary to equip the device with an extended or elongated nozzle.