| 摘要 |
PURPOSE:To make a titled device simple and compact and to obtain high pressing force by so constituting the device that the leading end of a piston shaft of a boosting cylinder is projected into a main pressurizing chamber via an oil feed chamber and is brought into abutment with the top surface of a main ram. CONSTITUTION:Low pressure oil is fed to the piping 4 of sub-cylinders 3, 3 and a pressurizing plate 2 is lowered quickly to mate a male die fitted to the plate 2 with a female die. At this time, negative pressure is developed in a main pressurizing chamber 8, and a surge valve 12 opens, so that the oil in an auxiliary oil tank 9 is sucked in to the chamber 8. Next, when low pressure oil is supplied from a piping 2, a boosting piston 21 is lowered, and the leading end part of a piston shaft 23 projects into the chamber 8, thereby pressurizing the inside of the chamber 8 and screwing down a main ram 7 under high pressure. The work is thereby pressurized and molded. Upon completion of the molding, the low pressure oil is fed through a piping 19 into an oil hydraulic working chamber 18, which in turn opens a valve 12 to feed the low pressure oil to a piping 5 and to return the oil in the chamber 8 into the tank 9. At the same time, the shaft 23 abouts on the top face of the ram 7, and is moved upward until it returns to the home position. |
