Self-drilling and thread-forming screw made of stainless steel and method for its manufacture

Abstract

A self-drilling, thread-forming screw made of stainless-steel has the following functional sections that merge into and/or are adjacent to one another: A screw tip, a truncated cone having a terminating dome, a cylindrical shank threaded at least in sections, and a head. A thread-like relief structure having longitudinally extended, arcuate ribs is arranged on the jacket of the truncated cone. These ribs, viewed in the longitudinal direction, are arranged one behind the other but spaced apart and follow a virtual helical curve. The screw is entirely manufactured of stainless-steel without post-manufacturing heat treatment to improve the material hardness by cold forming the screw head by upsetting. The screw tip is formed with the special thread-like relief structure consisting of the arcuate ribs, with this shape being achieved by a pinching movement transverse to the longitudinal axis between two opposing tool jaws. Protruding material is sheared off during subsequent thread rolling.

Dependencies are inferred from the claim text.