| 摘要 |
PURPOSE:To contrive to pressurize a pressurizing chamber without supplying hydraulic oil from outside to the pressurizing chamber when the mold is open and closed by a structure wherein a booster plunger is provided near the pressurizing chamber and an on-off valve is provided on the pressure loading surface of a pressurizing ram and, in addition, an oil tank is provided near a back chamber. CONSTITUTION:Firstly, the boosting chamber 30 of a boosting device (c) is evacuated so as to retreat a booster plunger 29 in order to reduce the pressure in a pressurizing cylinder 1. Secondly, a pressurizing chamber 6 and a back chamber 7 are communicated with each other by opening an on-off valve 3 by supplying hydraulic oil to the supplying and carrying-off port 25 of a piston 24. Thirdly, a movable platen 12 is advanced by supplying hydraulic oil to the supplying and carrying-off port 19 of a booster (a). At this time, the working oil in the back chamber 7 is transferred through a communicating hole 4 to the pressurizing chamber 6 and simultaneously the shortage of oil is supplied from an oil tank 9. Fourthly, after the on-off valve 3 is closed on the pressure loading surface by retreating the piston 24, the plunger 29 is advanced in the pressurizing chamber by sending hydraulic oil to the supplying and carrying-off port 33 of the boosting device (c) so as to pressurize the interior of the pressurizing chamber in order to obtain mold-clamping force. |
