Patent ID: 7160102
Filing Date: 2007-01-09
Classification: B29C

Abstract:
1. An injection unit for an injection molding machine, comprising: a plasticizing unit in the form of a continuously operated extruder having a forward end and including at least one plasticizing screw which is operated to continuously rotate; a plunger-type injection device including an injection nozzle for interaction with an injection mold, and an injection plunger demarcating anteriorly thereof an injection space which is connected to the forward end of the extruder by a melt channel and from which a shot amount is injected into the injection mold as the injection plunger moves forward; and a shutoff valve disposed in the melt channel, wherein the extruder is constructed to allow a backup of plastic melt such that a backup length is able to expand backwards into the extruder, when the shutoff valve is closed, for continuous production of plastic melt by the extruder.