PURPOSE: To control always the changeover of the injection speed of a molten metal to an optimum timing by providing a sensor into a runner communicating with a die cavity and detecting the top part of the molten metal.
CONSTITUTION: A sensor 20 is disposed in a runner 6 communicating with the cavity 4 of a die and the top part of a molten metal 9 in the stage when the molten metal 9 is driven by a plunger tip 10 and is pressed in the cavity 4 direction is detected by said sensor 20. The detection signal thereof is used as the signal relating to the operation control of a liquid pressure cylinder device for driving the tip 10. The injection speed is changed over from a low to high speed region by said signal. The timing for changing over the injection speed is set always exactly by the above-mentioned device regardless of the difference in the rate of pouring, etc.
MOCHIZUKI SHIROU
OKAMURA KATSUYA
