Progressively-formed clinch nut
AssigneePEM Management, Inc.
InventorsKenneth A. Swanstrom, Harold D. Ross, William P. McDonough
Life of this patent
Estimating the term…
Abstract
A three-sided, progressively-formed threaded fastener is comprised of a plurality of planar longitudinal faces intersecting at comer areas. Shank tabs extend downward from the bottom of each of the faces at the base of the fastener. Threaded regions along the inside surface of the planar faces are coined indentations applied during the formation of the fastener. A plurality of wedge-shaped protrusions extend downward from the comer areas at the base of the fastener. The combination of shank tabs and wedge-shaped protrusions form a clinch profile along the bottom of the fastener so that it may can be affixed to a sheet of metal by clinch fit.
Claims8
A threaded metal fastener, comprising:
- a tube-like channel having a polygonal cross-section and being comprised of a plurality of planar longitudinal faces intersecting at corners;
- a shank tab located at the bottom of each of said faces and extending axially downward from a base of said channel;
- a plurality of thread regions comprising longitudinal rows of indentations on an inside surface of each of said planar faces;
- a downwardly convergent wedge-shaped protrusion extending from the bottom of said channel beneath each corner;
- and
- said shank tabs each having angled side edges convergent upwardly whereby an undercut clinch profile is formed at the bottom of the channel, said profile providing means to permanently affix the fastener to a sheet of metal by clinch fit.
The method of forming a threaded metal clinch nut, having a tube-like, elongate channel of polygonal cross-section and a plurality of substantially planar faces which meet at corners, comprising the steps of:
- providing an elongate strip of metal;
- cutting said strip into fastener blanks with arcuate indentations in a front surface thereof said indentations arranged in spaced longitudinal rows and said blanks each including a shank tab extending downwardly from a bottom edge thereof beneath each row of indentations;
- and
- folding said strip into a tube-like channel along longitudinal foldlines located between said rows of indentations such that wells of said indentations define chordal sections of a space corresponding to an externally-threaded member.
Dependencies are inferred from the claim text.