| 摘要 |
<p>Two bolts pivot on the ends of arms extending from an upright which is joined to the end of a shoring prop. The bolts fix the panels rigidly to the upright, so that they cannot slip out of place. By turning the bolts by ninety degrees on their axes, the panels can be removed from the upright. The side ends of the lining-panels have C-shaped openings into which fit the bolts joined to the upright. The lining-panels may be moved along a path other than a vertical one.</p> |
