| 摘要 |
PURPOSE:To prevent the intrusion of molten metal into a valve device by closing the valve of a vent device for cavities by the effect of the inertial force of the molten metal or with a solenoid valve, by closing the valve beforehand with the solenoid valve in the case of low injection. CONSTITUTION:An injection cylinder 7 is operated to supply molten metal into cavities 8. The molten metal filling the inside of the cavities 8 flows through a vent groove 9 and enters a vent device 10, from which the gas is discharged to the outside, and a vent valve is closed by the effect of the inertial force of the molten metal. On the other hand, the injection speed of the molten metal is detected with a speed detecting sensor 33, and the detected value and the prescribed injection speed of a setter 37 are compared in a comparator 36. When the molten metal does not attain the speed necessary for closing the vent valve, a solenoid 21 is energized immediately to close the valve automatically. In the case of injecting the molten metal only by the low speed injection, a changeover switch 38 is changed over to energize the solenoid 21 so that the valve is beforehand held closed. |
