| 摘要 |
A fixing for fixing a waterproof membrane 6 and an insulation material 4 to a steel sheet 2 consists of a clamp plate 8 and a screw 10. The screw 10 comprises a head 11, a shank, and a drilling tip 14. The head 11 has a clamping face 12 which tapers towards the shank, and which has external angles 30 in cross section. The shank has, in succession from the head 11 to the drilling tip 14, a first portion 16 which is unthreaded, a second portion 18 which is threaded, and a third portion 22 which is threaded. The diameter of the first portion 16 is approximately the root diameter of the second portion 18, and the crest diameter of the second portion 18 substantially exceeds the crest diameter of the third portion 22. The clamp plate 8 is formed from sheet metal and has a central hole 24. The periphery of the clamp plate 8 is of elongate symmertrical shape having a minor dimension which is several times the diameter of the hole 24 and a major dimension substantially greater than the minor dimension. The clamp plate is generally flat with a countersink 28 around the hole 24, and with two endless gutter-like deformations 34, 36, the first one 34 adjacent the periphery, and the second one 36 approximately midway between the hole 24 and the first one 34. |
