| 摘要 |
<p>A device for keeping a working platform (18) of an access equipment in the desired position, said device comprising a hydraulical extendable boom (6, 29) one end of which is pivotally supported directly or by means of a second hydraulical extendable boom (6) by a fixed support structure (1), the other end (14, 36) pivotally carrying said working platform (18); in the vicinity of each pivoting shaft (5, 16, 39) a gear wheel or gear wheel segment (3, 15, 37) being mounted fixedly connected to one of the two parts rotatable with respect to each other, each gear wheel (3, 15, 37) engaging a gear rack (12, 22, 35) extending in the elongation of the piston-rod (11, 21, 34) of a double acting hydraulic motor (9, 19, 32) which is fixedly connected to the other part, the cylinder spaces (23, 24, 27, 28, 43, 44) of the hydraulic motors (9, 19, 32) being interconnected by conduits (25, 26, 41, 42) for hydraulic medium.</p> |
