PURPOSE: To compensate the shrinkage of a cast material when it hardens by the application of a prescribed pressure, by closing the communication between a casting material tank and a cylinder chamber by a slidable piston so as to force a casting material in a material tank into a molding chamber.
CONSTITUTION: The piston 6 is made to approach to a driving apparatus 9 to open an opening 4, a pressure is applied into the material tank 1, and a synthetic resin 12 in the material tank 1 is cast via a cylinder chamber 7 into the molding 10. The hardening reaction of the synthetic resin 12 cast into the mold 10 proceeds, and synthetic resin 12 contracts when it hardens. Therefore to compensate the shrinkage, the driving apparatus 9 is actuated for example by a signal issued by a pressure sensor or a signal issued according to an elapped time after the casting so that the piston is moved up. As a result, the opening 4 through which the synthetic resin 12 is fed from the material tank 1 to the cylinder chamber 7 is closed by the piston 6, and the synthetic resin 12 remaining in the cylinder chamber 7 is forced into the mold 10 by the movement of the piston 6.
FUJISAWA OSAMU
SAKAI RIYUUKICHI
