Overload preventing circuit for screw

Abstract

Abstract PURPOSE:To prevent an overloading on a screw of an injection molding machine by a method wherein a hydraulic motor is stopped by generating a signal when the difference between the hydraulic pressure at the inlet of the motor and that at the outlet of the motor exceeds a preset allowable limit. CONSTITUTION:In the case where a solenoid change-over valve 10 is not energized, a hydraulic pressure fed out from a pump 1 is exweted on the hydraulic motor 4 through a flow control valve 5 and a solenoid change-over valve 3 at a pressure set by a relief valve 9, and it rotates the motor 4 in accordance with the throttling amount set by the control valve 5. When an overload occurs on an injection screw 6, that is, when the difference between the hydraulic pressure detected respectively at the inlet and the outlet of the motor 4 by pressure detecting ends 7, 8 has exceeded an allowable range, a signal is generated by a signal generator 11 to stop the driving of the motor 4. Accordingly, the motor 4 is protected, and the screw 6 may not be damaged due to the overload.

Inventors

• 👤 Shingo Yugawa

Bibliographic Details