| 摘要 |
<p>PURPOSE:To prevent the falling accident of a vehicle due to sinking of a road surface by a method wherein it is detected whether or not a cavity part is present in a ground at the earthing part of the expandable leg part of an outrigger, and when the cavity part is present, it is displayed. CONSTITUTION:An outrigger 10 mounted to the front or the rear of an altitude working vehicle and stably supporting a car body is provided with a horizontally expandable beam part 12 and leg parts 14 arranged at both ends and vertically expandable. An earthing plate 16 on which a ground reaction force is exerted is mounted to the lower end of the leg part 14. In this case, a sensor 20 to transmit and receive electromagnetic waves between underground and the sensor through the window of the earthing plate 16 is mounted to the leg part 14. When a cavity part 24 having a specified size is present in a ground, the cavity part is detected by the sensor 20 and is decided by a signal processing device 22. Simultaneously, a display unit 26 displays danger, and a hydraulic control device 28 to expand and contract the leg part 14 is controlled.</p> |
