| 摘要 |
<p>A column (10) is attached at a base flange (15) to a plate (16) of a base member (11) by way of an offset horizontal pivot (13), and can be pivotally raised and lowered by means of a ram (14). The pivot (13) lies in the general plane of the flange (15) and the plate (16) so that, when the column (10) is fully lowered, the overall height of the unit in the region of the base member (11) is little more than the length of the flange (15).</p> |
