| 摘要 |
PURPOSE:To contrive to make the cycle speed of a mold clamping device higher and to stabilize the braking function of the device by a structure wherein a controlling cylinder, the other end of a prefill valve piston of which forms a small gap together with a communicating port at the limit of the stroke of the piston, and an oil hydraulic circuit for controlling the actuation of the piston and the like are provided. CONSTITUTION:When the cooling and solidification of the injected resin at the completion of an injection process comes to an end, a solenoid selector valve 14 is magnetized to its B position and a solenoid selector valve 15 is demagnetized in order to start the retreating of a mold clamping ram 2 at high speed and a piston 25 is retreated and the piston 31 of a controlling cylinder 28 is retreated at the speed set by a flow control valve 30. When the mold clamping ram 2 reaches the position, which is a little ahead the limit of backward movement, a detecting switch of the low speed position in the backward movement of the mold clamping ram is put into actuation so as to change over the delivery of a pump 16 to the smaller one, magnetize the solenoid selector valve 15, escape the pressure oil in the oil chamber 12a of a prefill valve into an oil tank 5 and at the same time the piston 25 is moved rightwards and similarly the piston 31 of the controlling cylinder 28 is moved rightwards in order to make a small gap Y between a communicating port 26 and a stepped part 27, resulting in effectively braking the backward movement of the mold clamping ram 2. |
