PROBLEM TO BE SOLVED: To effectively use pressure oil by supplying control flow to a rolling control valve side, and sending whole quantity of pressure oil at an upstream side of a flow distributing valve to a lift control valve side at the time of neutral position operation during which rolling control is not executed.SOLUTION: This device includes: a flow distributing valve 38 capable of distributing and supplying pressure oil to the lift control valve 42 and the rolling control valve 39 and a control means 14A controlling the flow distributing valve 38 so as to supply control flow to the rolling cylinder 11 side and to supply surplus flow to the lift cylinder 9 side when the rolling control valve 39 is operated to a position at which pressure oil is supplied to the rolling cylinder 11 side, and controlling the flow distributing valve 38 so as to supply whole quantity of pressure oil at the upstream side to the lift control valve 42 side when the rolling control valve 39 is operated to the neutral position at which supply of pressure oil to the rolling cylinder 11 side is stopped.COPYRIGHT: (C)2011,JPO&INPIT【課題】ローリング制御弁側へ制御流を供給し、ローリング制御が行われない中立位置操作時は、流量分配弁よりも上流側の圧油の全量を昇降制御弁側へ送り込み可能にして、圧油の有効利用を図る。【解決手段】昇降制御弁42とローリング制御弁39とに圧油を分配供給可能な流量分配弁38を備え、ローリング制御弁39がローリング用シリンダ11側へ圧油を供給する位置に操作されると、ローリング用シリンダ11側に制御流を供給し、余剰流が昇降用シリンダ9側へ供給されるように流量分配弁38を制御し、ローリング制御弁39がローリング用シリンダ11側への圧油供給を停止する中立位置に操作されると、上流側の圧油の全量を昇降制御弁42側へ供給するように、流量分配弁38を制御する制御手段14Aを備えた。【選択図】図4
