| 摘要 |
<p>An integral moulding of a resilient plastics material comprising a first portion and a second portion hinged together by a web of small width and thickness; the first portion having a recess facing towards the web, and a lip bounding the recess at one side and directed towards the web; and the second portion having a rib directed away from the web; the relative distances of the lip and rib from the web being such that relative rotation of the first and second portions in one direction will cause the rib and lip to engage each other and continuation of the rotation in that direction will cause the rib and lip to ride past each other until the rib lies in the recess.</p> |
