| 摘要 |
The present invention is directed to a cold-rolled screw intended for screwing into plastic. The screw has a self-tapping thread having thread turns. The thread turns are configured approximately in the manner of knife blades in cross-section. A flank surface of the thread turns has an inwardly directed inflection approximately in the central third forming an outer flank angle of approximately 30 .degree. between the inflection and the thread crest and an inner thread angle between the inflection and the thread root. The inner flank angle, on average, is essentially equal to or greater than 1/3 of the outer flank angle. |
