Switching circuit for intermittently operating hydraulically operated machines

摘要

When operating a hydraulic drive the hydraulic control pipe (15) designed as the load warning lead (15) is hydraulically biased through an end chamber (13,14) of each control block (11,12) from the pressure pipe (10). The pneumatic control slider (4) is hydraulically biased through a branch pipe (16).The control slider can also still be controlled by a pneumatic control pipe (24), a shut-off valve (25) mounted therein and a control valve (26) which in turn is biased by a hydraulic control pipe (27) which is connected with the pressure line of the hydraulic pump (8) before entering into the control blocks. The hydraulic pump can be a load-sensing pump connected to the hydraulic control pipe through a hydraulic branch pipe (17), volume regulator valve (18), pressure regulator valve (19) and servo cylinder (20).