Mitsubishi Gas Chemical Company, Inc.

Plastron Corporation

Tetsuya Hozumi

Akimasa Kaneishi

A drive apparatus for driving a movable member of a plastic molding die apparatus is provided which drives and controls a movable shaft for holding a gas injection nozzle by using a plurality of cylinders so that the gas injection nozzle of the die apparatus for use in a gas injection molding method can easily be changed. Resin is supplied from a position through a second die into a cavity formed between a first die and the second die, the drive apparatus disposed adjacent to the first die is used to drive the movable shaft for holding the nozzle of a gas supply means to supply gas into the resin in the cavity so that a hollow product is molded. The nozzle of the gas supply means is disposed at the leading portion of the hollow movable shaft. The drive apparatus includes a plurality of cylinders which are disposed at fixed positions adjacent to the first die with respect to the movable shaft and which are substantially the same, a connection plate for establishing the connections among rods of the plurality of fluid cylinders and the movable shaft, and a fluid control source for simultaneously driving the plurality of cylinders. The rod of each fluid cylinder and the connection plate are connected to each other while having plays in the axial direction and the radial direction.

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Nihonmatsu, Japan

Tetsuya Hozumi