| 摘要 |
The device (2) comprises interengaging hook parts (7-9) and at least one of the side edges (3-6). The hook parts has a slide surface (18) upwardly/downwardly sloping in a direction (11,12) form the plate top side (16) or under side. The slide surface is arranged so that two plates which are pushed together along the roof plane can slide overlapped. After fitting the slide surfaces, the plates are placed so that an upper hook part (7) secures at the back of a lower hook part (8). |
