| 摘要 |
PURPOSE:To provide an economical device of simplified constitution by detecting the pressure of a cylinder when a car sinks, and supplying pressure oil to the cylinder according to the pressure detected. CONSTITUTION:If the load of a car 1 is increased with a passenger or cargo getting into the car, oil in a cylinder 2 is compressed and pressure within the cylinder is built up. Therefore pressure within a pilot pressure chamber 19 is built up but pressure within a pilot pressure chamber 20 is not built up, so a three-port switching valve 6 is moved in the direction in which it pushes a spring 16, and then oil discharged from a sub-pump 4 thrusts up a check valve 8 and is supplied into the cylinder 2, whereby the car is positioned. When a car position detector 17 detects that the car has returned to its initial position, a solenoid switching valve 7 is operated once to equalize pressures within the two pilot pressure chambers 19, 20 so as to return the three-port switching valve 6 to its initial position. Therefore, the oil discharged from the sub-pump 4 flows back into a tank and positioning of the car is completed. |
