| 摘要 |
811,247. Hydraulic systems. CITROEN S.A., A. Jan. 18, 1957 [Sept. 14, 1956], No. 1894/57. Class 69 (2). [Also in Group XXXII] In an hydraulic system comprising a continuously operated pump P and two opencentre control valves D<SP>1</SP>, D2 each controlling the operation of a motor, a valve S is provided which automatically discontinues the supply of liquid to one control valve when the other valve is actuated to connect its associated motor to the pump, and automatically restores the supply to the one control valve if this valve is subsequently actuated. The control valves D1, D2 and their operation are identical. Considering valve D1, in the central position shown pump P discharges through valve S and a line 4 to this valve and thence through a line 37 to a reservoir R. A line 21 leading to an end chamber of the valve S is also connected to the reservoir through valve D1. Movement of the valve spool 24A to the left blocks the reservoir line 37 and opens a motor line (not shown) to line 21 and to the inlet line 4. The resulting increase in pressure in line 21 moves the valve S to the left, closing the supply line to the control valve D2, so that control valve D1 only is supplied. If the spool of the valve D2 is now moved to the left, so that both valves are actuated, its motor line is opened to a line 20 leading to the other end chamber of valve S, and the pressure in this motor line centralizes the valve S and both control valves are supplied. |
