| 摘要 |
<p>A fastening device for fastening to a solid support roofing panels laid on a soft insulating material are provided with a self-boring and thread-cutting screw (4) and with a wide plain washer (5). An intermediate sleeve (6) can be mounted between the screw (4) and the plain washer (5). The screw (4) has two threaded sections (9 and 10) separated by an unthreaded section (7), the threads of these two threaded sections (9, 10) extending in opposite directions The outer diameter of the thread of both threaded sections (9, 10) is bigger than the throughhole (14) of the intermediate sleeve (6). The opposite threads running in opposite directions of the threaded sections (10) prevent loosening of the screw (4).</p> |
