| 摘要 |
PURPOSE:To provide a clamping device for a mold, compact and light, by carrying out the mold opening and closing by pressurizing a mold closing chamber and a high speed mold closing chamber respectively and operating an on-off valve on the opening side only by means of a cylinder space. CONSTITUTION:High speed mold closing is carried out by feeding pressurizing oil into a chamber D in the state of mold opening. At that time, since the sum of effective pressurized area of a chamber B and a chamber C is is set almost equal to the effective area of a chamber A, the volume of oil discharged out of the chambers B and C and the volume of oil required by the chamber A are almost equal never to make the pressure inside the chamber A negative. The flow rate of pressurized oil fed to the chamber D is continuously reduced and the mold closing is carried out at low speed and low pressure, and then the chamber A is pressurized. As differential pressure is generated in front and in rear of an on-off valve 25 by said process, the ON-OFF valve 25 is moved forward and backward and the end face of its sleeve-shaped section 26 is brought into contact with a piston section 21 of a clamping ram to close a communicating line 22. The pressure oil fed to the chamber A thereafter acts on the rear end surface of the clamping ram 20 by the arrangement to carry out a powerful clamping. An injection device 17 is moved forward by dwelling in the state and molten resin is injected into a mold for the required molding. |
