| 摘要 |
PURPOSE:To enable to decide that an elevating apparatus supports the weight of either a pontoon or a leg post, by a method wherein a position, where an engaging number of a frame fitted in the leg post makes contact with a rack mounted at the leg post, is detected. CONSTITUTION:Two frames are securly fitted in a leg post vertically movably mounted at a pontoon, and a device, which can engage and disengage the rack, and an elevating cylinder are provided at the two frames. A device, which can detect a position allowing the engaging part to make contact with the rack, is mounted at the engaging device, and the signal from the device is caused to decide that the elevating device supports either of the loads. For example, if the engaging part 9, fitted in the trough of a rack tooth 4, supports the weight of the leg post 2, a detector 51a sends a signal, and conversely, if it supports the pontoon, a detector 52a transmits a signal. In the case of engaging part 17 as well, the signals are generated in the manner described in the engaging part 9. If engagement or disengagement of the engaging part is carried out by means of cylinders 10 and 18 through the utilization of said signals, this permits the appropriate transfer of the load to the engaging parts. |
