Patent attributes
The invention relates to a screw fastener comprising a threaded shank having a force application means for torque transmission and a screw fastener point. The threaded shank consists of a shank core and a self-tapping thread, and the thread is designed as a prominence which runs helically over the shank core, is defined by two flanks meeting in an outer thread edge and has a radial height (H). The outer thread edge, at least in a section of the thread, runs in a wavelike manner in the radial direction with an amplitude between wave crests having the height (H) and wave troughs having a height (h) reduced by the amplitude. The thread, at least in the region of one of its flanks, has niches in the region of the wave troughs of the thread edge, which niches interrupt the surface of the flank and their outer boundary is the thread edge, the thread in each case having a certain first apex angle (α), formed between the flanks, in those regions of the wave crests of the thread edge which are not interrupted by niches and a second apex angle (α′) in the deepest regions of the wave troughs of the thread edge. The first apex angle (α) between the flanks is approximately within the range of 30° to 35°, the second apex angle (α′) being 30° up to at most 58°.
