REGULATING METHOD FOR UPPER LIMIT OF DIE CLAMPING FORCE IN MOLDING MACHINE HAVING TOGGLE TYPE DIE CLAMPING MECHANISM

摘要

PURPOSE:To avoid excessive reclamping by stopping die clamping operation when the stroke position for high pressure selection exceeds ths stroke position of a die clamping cylinder corresponding to a max. die clamping rate, that is, a max. die reclamping rate. CONSTITUTION:After dies D1, D2 are mounted respectively to the opposed surfaces of stationary and moving die plates 2, 4, oil pressure is fed to a die clamping cylinder 10 to clamp the dies with toggle mechanisms 5. Here, during die clamping, the stroke position thereof is detected with a potentiometer 19 or the like and the detected voltage Ex thereof is fed to an arithmetic device 20. The reference and set voltages E0, E1 corresponding to the stroke positions of the cylinder 10 at which the max. permissible die clamping force of the molding machine and the optional die clamping force to be set by the operator are generated are beforehand stored in the device 20. The voltage Ex is compared with the E0, E1, and when Ex=E1 and E1=E0, a high-pressure changeover valve 16 is operated to interrupt a low-pressure relief valve 17, and when Exnot equal to E1or E1 E0, the valve 17 is held as it is and a selector valve 12 is operated toward die opening, whereby the die clamping operation is stopped.