Screw and its utilisation

摘要

The screw has a set of screw threads (7, 8) sweep in a region of a drive end (3) of a screw shaft (1) with a screw head (4). External diameter of the head is greater than 1.5 times of external diameter of one of the screw threads. The shaft includes a holding section (6) with the screw threads, where the holding section is provided from the drive end. A thread-free screw section (9) is provided adjacent to the holding section and a front screw-in section with another set of screw threads and a front screw end, where a pitch of the screw threads is identical to the screw section.