| 摘要 |
A molding machine for molding foam plastic material such as, for instance, polystyrene beads, comprising a plasticizing extruder mechanism including an extruder barrel for plasticizing and heating the foam plastic material and possessing the ability to maintain the heated plastic material under sufficient pressure to prevent the foaming thereof in the machine, with a nozzle coacting with the barrel, for injecting the heated plastic material into a mold, and with shutoff means coacting with the leading or emitting end of the nozzle for controlling the flow of heated plastic material out the emitting end of the nozzle, and preventing foaming of the plastic material in the nozzle, and in the extruder barrel, but permitting high-pressure ejection of the heated plastic material out through the emitting end of the nozzle into the mold upon movement of the shutoff means to inactive position, after which the shutoff means moves back to active cutoff position. Foaming of the heated plastic material occurs in the mold to form the finished part.
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