| 摘要 |
PCT No. PCT/DE90/00685 Sec. 371 Date Mar. 6, 1992 Sec. 102(e) Date Mar. 6, 1992 PCT Filed Sep. 7, 1990 PCT Pub. No. WO91/03603 PCT Pub. Date Mar. 21, 1991.A bridge underview device includes a chassis; a turntable mounted on the chassis and being rotatable about a vertical axis; a bearing element mounted on the turntable by a first pivot joint for a swinging motion about a horizontal axis of the first pivot joint; a guide member; an elevating tower mounted on the guide member for gliding displacement relative to the guide member; a first arm coupled to the bearing element by a second pivot joint and to the guide member by a third pivot joint; and a second arm extending parallel to the first arm and being coupled to the bearing element by a fourth pivot joint and to the guide member by a fifth pivot joint. The second, third, fourth and fifth pivot joints each have a horizontal axis, whereby the guide member and the elevating tower are swingable as a unit relative to the bearing member in a vertical plane while maintaining an unchanged orientation. There are further provided positioning devices for maintaining the bearing member in a desired angular position relative to the chassis and for maintaining the guide member in a desired distance relative to the bearing member. |
