Self-flanging nut and joint construction

Claim 1

In a self-flanging nut construction, the combination comprising a tubular body having a laterally extending annular flange at one end and an opening therethrough, said flange having a substantially flat outer surface coextensive with said end of said body, said opening having a first portion and a second portion of differing cross sectional area, the outer surface of said tubular body being cylindrical, said first portion of said opening in said body adjacent said flange being formed with a thread substantially throughout its axial extent, said second portion defining a riveting flange having a free end remote from said first portion, the inner surface of said second portion being uniformly tapered inwardly in the direction of said first portion substantially throughout its axial extent, the outer edge of said free end of said riveting flange being curved at a given radius smoothly blending into said cylindrical outer surface, the inner edge of said free end being curved at a lesser radius than said outer edge and smoothly blending into said tapered inner surfce of said second portion, a plurality of circumferentially spaced ribs on the cylindrical periphery of said body adjacent said flange and extending axially along said body, the length of said ribs being substantially equal to the axial length of said first portion of said body, the thickness of said flange being less than the length of said ribs, each said rib being generally U-shaped in cross section and having a greater width than thickness, the circumferential spacing between said ribs being several times greater than the width thereof such that a portion of the cylindrical periphery of said body is interposed between adjacent ribs, each said rib extending from said flange toward said second portion to form a free end, said free end of each said rib being tapered, the radial thickness of said second portion of said body being substantially constant throughout and having an internal surface which is slightly tapered inwardly, the radial thickness of said second portion being such that when the nut is placed adjacent a sheet metal plate having an opening therein with the opening in alignment with the opening in the nut and the nut is forced against said sheet metal plate, the metal surrounding said opening in said plate is deformed axially of the opening by said second portion to form a tubular portion, and thereafter when an axial force is applied to said free end of the riveting flange, the riveting flange is deformed laterally outwardly over the tubular portion formed on said plate.