| 摘要 |
PURPOSE:To decrease arrangement space and improve responsiveness by closing the first change-over valve and the third changing-over valve and opening the second changing-over valve at the time of vehicle running start to drive a hydraulic cylinder for increasing a vehicle floor height, and opening the first changing-over valve and the third changing-over valve and closing the second changing-over valve to decrease the vehicle floor height at the time of vehicle stopping. CONSTITUTION:When a height control switch 29 is ON, the second changing-over valve 22 is in an open condition at the time of vehicle running start, so that the pressure oil from a hydraulic pump 12 is fed to the first pressure chamber 11b of a hydraulic cylinder 11, and at the same time, the oil in the second pressure chamber 11c returns to a reservoir tank 13. The first changing-over valve 21 and the third changing- over valve 24 closes, so a vehicle floor height goes up from a low position to a normal position. At the time of vehicle stopping, the third changing-over valve 24 opens with the first changing-over valve 21 opened and the second changing-over valve 22 closed, so the oil in the first pressure chamber 11b is fed into the second pressure chamber 11c of the hydraulic cylinder 11, the vehicle floor height decreases from the normal position to the low position. |
