Pressure molding apparatus for molten resin having a limit switch which

Abstract

A pressure molding apparatus for supplying molten resin to a mold includes a gate unit having an aperture therein for passage of molten resin into a mold cavity of the mold, a gate pipe connected for communication with the gate unit, and a gate pin which is axially movable within the gate pipe. The gate pin has a gate pin end at one end and a tip at another end thereof, the tip being engageable with the aperture for controlling flow of molten resin through the gate unit. The apparatus also includes a manifold pipe for supplying molten resin to the gate pipe, a connection arrangement for connecting the gate pipe to the manifold pipe. The connection arrangement includes a receiving portion for receiving molten resin from the manifold pipe, the gate pin passing completely through the receiving portion and the gate pin end extending beyond the connection arrangement. A limit switch arrangement is provided for detecting movement of the gate pin end to a predetermined position, the limit switch arrangement producing a signal indicative of whether the gate pin end is at the predetermined position. A molten-resin supply pipeline is also provided which includes a base pipe for supplying the molten resin to the interior of the manifold pipe, and the base pipe is connected to the manifold pipe by a pillar pipe.