Patent ID: 7101133
Filing Date: 2006-09-05
Classification: F16B

Abstract:
1. A screw fastener comprising a force application means for torque transmission and ending in a screw fastener point, said screw fastener also consisting of a shank core and a self-tapping thread that follows a helical path over an outer surface of said shank core, and characterized by two flanks meeting in an outer thread edge having a radial flank height defined between the outer thread edge and the outer surface of the shank core and; wherein the self-tapping thread runs in a wavelike manner along the helical path of the outer thread edge, the self-tapping thread including wave crests with a maximum radial flank height and a maximum thread thickness; wave troughs with a minimum radial flank height and a minimum thread thickness which define a boundary line between the wave crests and the wave troughs, the maximum radial flank height being larger than the minimum radial flank height, with a difference between the maximum radial flank height and the minimum radial flank height defining an amplitude and, wherein at least one of the flanks has a plurality of radially extending niches in one of the wave troughs, having a beginning at the outer thread edge and having an end at the boundary line, the distance between the beginning and the end defining a radial depth and, wherein the self-tapping thread is further characterized by a first apex angle, formed between the flanks near the wave crests of the thread edge in an area not interrupted by niches, and a second apex angle formed within the niches, between the interrupted surfaces of the flanks near the minimum radial flank height of the wave troughs of the thread edge, the first apex angle being approximately 30° to 35°, and the second apex angle being approximately 30° to 58°.