| 摘要 |
<p>The connection-piece is fixed between two roof-purlins in order to form a more rigid structure and has a U-section body (7) with a rectangular section head (8) made from a thick iron bar. The section of the head (8) is such that it can pass through an opening in the roof-purlin (1) when it is rotated at 90 deg. around its longitudinal axis. On the top part of the head is groove (9). Once the head has been inserted through the opening in the purlin, it is prevented from going any further by rotating until an edge on the opening is wedged into the groove (9).</p> |
