| 摘要 |
Improvements to devices making it possible to ascend posts, including a first element (1) with two bearing and counterbearing surfaces, a second element (2) connected to the first element (1) by links (3 and 4) and provided with a bearing and counterbearing surface, characterised in that each element (1 and 2) on bars (9, 9a) includes cheeks (covers) (10, 10a), the wings of which support two shafts (12, 13) on which rollers (14, 15) are guided, the counterbearing surfaces (40, 49) being carried by one of the ends of movable bars (19, 19a) guided between the said rollers (14, 15) and the free ends of the said movable bars (19, 19a). <IMAGE>
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