CONTROL METHOD AND CONTROL CIRCUIT FOR DRIVE JACK AND CUTTER DRIVING METHOD AND CUTTER DRIVING DEVICE FOR GROUND EXCAVATOR

摘要

PROBLEM TO BE SOLVED: To substantially equalize force for pushing out with force for pulling of a piston rod.;SOLUTION: This drive jack 1 comprises a cylinder 2, a piston 3 and a piston rod 4, and is hydraulically actuated. In this case, pressure of hydraulic fluid P1, P2 supplied to a piston head chamber side and a piston rod chamber side inside the cylinder 2 are controlled such that pushing out force F and pulling force F' of the piston rod 4 are substantially the same.;COPYRIGHT: (C)2000,JPO