Hydraulic circuit arrangement for operation of mechanically coupled fluid-actuated hydraulic cylinders in working machine, has pressure relief valve maintained in open position until working pressure is below predetermined closing pressure

摘要

The arrangement has double acting hydraulic cylinders (6, 7) with bottom sides (Z2, Z4) hydraulically connected to a supply terminal (P1), and rod sides hydraulically connected to a drain terminal (P2), where the hydraulic cylinders are driven by inflow of a pressure medium. The working pressure of the pressurized bottom sides of the cylinders are controlled by pressure-dependent switchable main control valves (22, 23). A pressure relief valve (130) is adjustable to be maintained in an open position until the working pressure is below a predetermined closing pressure.