| 摘要 |
A screw contains a thread (5) extending from a screw drive end (2) of a cylindrical screw shaft (1) up to a screw tip (4). The screw tip is arranged at the end of a front cone portion (3) of the screw. The screw contains four ribs (10) which extend in the axial direction and begin at the front end of the cylindrical screw shaft and reach almost up to the screw tip. The screw also contains four ribs (11) in the region of the screw drive end, these ribs being arranged such that they are offset, in the circumferential direction, relative to the front ribs by half the angular distance between two ribs. |
