| 摘要 |
The chain wheels (19, 20) for the endless chain (21) used to move the telescopic parts (10-12) relative to each other are housed in a unit (16) inserted into the middle part (11). Rods (22, 26) movable in the column length section connect both chain runs to the top end of the top part (12) and bottom end of the bottom part (10). |
