| 摘要 |
The screw (10) is especially for use in chipboard, and has a head (1) with drive equipment (2), and a roughly cylindrical shaft (3) with a self-tapping thread (5). The latter has an asymmetric profile, and has one flank (22) which faces the head, and another flank (20) which faces the tip (4) of the screw. The former flank makes a larger angle with a plane which is normal to the longitudinal axis (6) of the screw, than does the other flank. The profile of the thread changes in the region of the tip, and the flanks tend towards a symmetrical shape. The angles which the flanks make with the plane may not change in the region of the tip, and in a region which merges into it. |
