| 摘要 |
PROBLEM TO BE SOLVED: To effectively use pressure oil and reduce operation shock of a lift cylinder by sending whole quantity of pressure oil at an upstream side of a flow distribution valve to a lift control valve side at a neutral position of a rolling control valve.SOLUTION: This device includes a control means 14A returning the rolling control valve 39 to the neutral position 39c and changing over the flow distribution valve 38 to a distribution supply position 38b when the rolling cylinder 11 reaches an operation limit position and a relief valve 36 discharges pressure oil to an oil tank T side, and setting increase rate of pressure oil supply quantity to the lift cylinder 9 side by the lift control valve 42 slower than increase rate of pressure oil supply quantity in operation at the time excluding discharge operation of the relief valve 36 when the lift control valve 42 is operated during discharge operation of the relief valve 36. |
