| 摘要 |
<p>The frame supports the plastic sheet used to construct tunnel cloches. It comprises several straight longitudinal tubes, assembled to vertical curved tubes and spaced at intervals. The longitudinal tubes (12) have U shaped metal clips, the base (1) of each being welded (3, 4) to the tube at the required spacings. The open end of each clip is traversed by a bolt (7), passing through holes in its sides (5, 6). The curved tube (10) is gripped inside the clip by plastic or similar wedges (8, 9) inserted under the bolt and held as this is tightened up. The curved tube base bears on the base of the clip.</p> |
