Control change system for a hydraulic work vehicle

摘要

A control change system for a backhoe in a construction vehicle, comprising a plurality of pilot valves for generating a pilot pressure corresponding to operations of a first and a second control levers, respectively, and a hydraulic switching unit for relaying the pilot pressure from the pilot valves and supplying the pilot pressure to a plurality of control valves. This switching unit includes a plurality of slidable spools for supplying the pilot pressure from the pilot valves selectively to the control valves. The control system further includes a first and a second switching members for selectively sliding the plurality of slidable spools. The first switching member is operable to select the swing cylinder or the hydraulic motor to be controlled by a shift in one direction of the first control lever. The second switching member is operable to switch interlocks between the first and second control levers and a boom cylinder and an arm cylinder.