INJECTION LIQUID PRESSURE CIRCUIT FOR INTENSIFYING DIE CASTING MACHINE

摘要

PURPOSE:To provide a titled injection liquid pressure circuit which enables an ideal change in speed and pressure increase by providing means for causing self- closing of solenoid operated changeover valves connecting to an accumulator and opening and closing valves relating to the speed change and pressure increase in a short time. CONSTITUTION:A quick opening pilot-operated check valve A30, a quick closing pilot-operated check valve 40 and a quick opening pilot-operated check valve 41 are connected to a hydraulic accumulator 21 in an intensifying die casting machine. When said valve A30 and valve 40 open, the pressure oil in the accumulator 21 is fed to the pressure chamber 3 of a single acting cylinder 1. The pressure oil is fed to the pressure chamber 42 of a intensifying cylinder 4 when the valve A30 and valve B41 open. The pilot of a pilot-operated check valve 58 connected to the valve A30 receives the pressure oil in the accumulator 21 through solenoid-operated changeover valves 60, 29 and a pilot-operated check valve 28. The leakage from the accumulator 21 is eliminated and the changeover to a high speed and a pressure increase is smoothly accomplished by such circuit.