| 摘要 |
The present invention pertains to a high speed fastening screw (3) comprising a plurality of concavities (321) formed on the threads (32), which are longitudinally connected for being arranged as a state of a single helix. Further, the concavities (S, t) separately located adjacent to the screw head (30) and to the drilling portion (33) are disposed at relative positions for being accurately aligned by an imaginary line (.beta.). In this manner, the configuration of the concavities would efficiently cut and sever the fibers of the object, so as to achieve a lower screwing resistance for a higher screwing efficiency and prevent the injuries to the operators. |
