TRACTOR HITCH HYDRAULIC SYSTEM Russian patent published in 2000 - IPC

FIELD: agricultural engineering. SUBSTANCE: hydraulic system has pump 1, hydraulic cylinder 3, drain tank 2 and distributor 4 connected to pump and drain tank via hydraulic pipelines. Distributor 4 has housing with channels 8. One of channels 8 is connected to pipeline 14 of hydraulic cylinder 3, connected to channels of control slide valve 5, return and discharge valves 13,6, and spring-biased retarding valve 21 of slide valve 5 having interconnected outer channel 23 and axial through opening 22 terminating at one end in nozzle 24. Control slide valve 5 has axial and radial openings 20,25 which are adapted for defining variable throttle with working edge connected to hydraulic cylinder of channel 8. Retarding valve 21 with outer channel 23 is mounted for axial displacement in axial opening 20 of control slide valve 5. Edge of outer channel 23 defines second variable throttle with radial openings 25 of control slide valve 5. One end of control slide valve 5 with nozzle 24 is positioned at discharge side and spring-loaded, and other end defines with axial opening 20 of control slide valve 5 control cavity 27. EFFECT: increased efficiency, reduced metal usage and decreased loss of hydraulic power. 1 dwg