| 摘要 |
In order to permit a favourable initial torque and uniform screwing in of a self-tapping screw consisting of a cylindrical shank having an integrally formed head and tapering at the end, the tapered end having the shape of a five-sided truncated pyramid, is proposed that the truncated-pyramid-shaped end (3) has a length of 2.5 P and constitutes only a part of the length of the conical taper (4), the latter merging into the cylindrical screw shank part (1) after six thread pitches, in that the thread tips become flatter from this transition point toward the end, and approach the core of the shank towards the end, and in that v-shaped grooves (6) are formed out, starting between the surfaces of the truncated pyramid, extending into the cylindrical shank part (1) and cutting the thread pitches, and whose depths reach the core of the shank and enclose a larger angle with the centre axis of the shank than that which corresponds to the thread pitch angle. <IMAGE> |
