Tractor hydraulic lift control unit - has stop valve and face spring-loaded against control pressure valve

摘要

The control unit is for a farm tractor hydraulic lift system, having a double pilot valve moved axially in a housing by an emitter actuated by the implement, also a control pressure valve regulating the main valve for the fluid flow to the lifting ram dependent on pressure in a control pipe. A stop valve controls the return flow from the ram, and one of the valves is thrust by a spring on a fixed support against the emitter. An end face (57) of the stop valve (30) is thrust by a spring (32) against a face (48) on a control portion (45) of the control pressure valve (12), while its outer surface controls the release of pressure from the ram pressure pipe (35) to the return pipe (36).