METHOD FOR SETTING SCREW Russian patent published in 2000 - IPC

FIELD: machine engineering, namely methods for setting self-drilling screws. SUBSTANCE: at drilling process or at forming opening by means of self-drilling or self-forming screw and also by means of thread-forming or thread-cutting screw having drilling portion or end portion for forming opening and stem with self-forming or self-cutting thread, screw is subjected to axial impact action due to continuous percussion movement created as in perforators. At next stages of thread forming or thread cutting value of impact action is the same or it is reduced. Screw is joined with rotation drive unit at process of drilling or forming opening and it is subjected to axial percussion action. Effort of such action is reduced directly after complete penetration of drilling portion of screw or its end portion forming opening (but before inlet of first turn of thread) into turning or opening. Switching from axial action to reduced effort percussion action is realized due to axial unloading directly after terminating process of drilling or forming opening or due to use of preliminarily adjusted stopper for limiting depth. EFFECT: enhanced reliability of method. 5 cl, 3 dwg