PIERCE NUT
The present disclosure is related to pierce nuts and, more particularly, to pierce nuts for thin and ultra-thin metal sheets. Exemplary embodiments of the present disclosure describe lightweight, high strength, structural nuts designed to pierce and clinch in ultra-high strength thin gage materials and ultra-thin metals. The pierce nuts include cavities radially disposed on a bottom surface having a teardrop radial form which allows for usage in thin ultra-high strength metals.
1 . A pierce nut for attachment to a sheet of material comprising:
a generally cylindrical body having a top surface and an annular-shaped bottom surface;
an internal bore extending through the cylindrical body from the top surface to the bottom surface and configured to receive a fastener;
a pilot portion coaxial within the cylindrical body and extending outwardly from the bottom surface; and,
a plurality of radially spaced apart cavities recessed in the bottom surface surrounding the pilot portion, each cavity having a set of opposing spaced apart sidewalls and a teardrop shaped vertical cross-section comprising a substantially continuous base wall having a sloped portion that linearly increases in depth toward a center of the pierce nut and converging with a concave divot portion.
2 . The pierce nut according to claim 1 , wherein the opposing spaced apart sidewalls are perpendicular to the bottom surface.
3 . The pierce nut according to claim 1 , wherein the opposing spaced apart sidewalls are inclined at an angle, the angle defined between a sidewall and a line perpendicular to the bottom surface, the angle ranging from about 1 degree to about 7 degrees.
4 . The pierce nut according to claim 3 , wherein a sum of the angles for the spaced apart sidewalls of each cavity is less than or equal to about 12 degrees.
5 . The pierce nut according to claim 1 , further comprising at least one planar tool receiving surface disposed on the nut body and adjacent to the top surface.
6 . The pierce nut according to claim 1 , wherein the concave divot portion has an arcuate cross-section with a radius from about 0.1 mm to about 0.5 mm.
7 . The pierce nut according to claim 1 , wherein the concave divot portion has an arcuate cross-section with a radius from about 0.2 mm to about 0.35 mm.
8 . The pierce nut of according to claim 1 , wherein the internal bore is threaded.
9 . The pierce nut according to claim 8 , wherein the threads are ISO metric screw threads in the range of M 4 to M 18 .
10 . The pierce nut of claim 1 , wherein the pilot portion comprises an exterior angled sidewall portion adjacent to the bottom surface.
11 . The pierce nut according to claim 8 , wherein the pilot portion comprises a substantially vertical exterior edge wall disposed between the exterior angled sidewall portion and a terminal end of the pilot portion.
12 . The pierce nut according to claim 1 , wherein the pilot portion comprises an inner surface wall in communication with the bore, the inner surface wall having a diameter that increases toward a terminal end of the pilot portion.
13 . The pierce nut according to claim 1 , wherein the bottom surface is flat.
14 . The pierce nut according to claim 1 , wherein each cavity of the plurality of cavities is formed from three (3) faces.
15 . The pierce nut according to claim 1 , wherein the plurality of cavities is from 10 cavities to 13 cavities.
16 . The pierce nut according to claim 1 , wherein the plurality of cavities is from 11 cavities to 12 cavities.
17 . The pierce nut according to claim 1 , wherein each cavity gradually increases in depth from a peripheral edge surface of the bottom surface toward the pilot portion.
18 . The pierce nut according to claim 1 , wherein the opposed spaced apart sidewalls are spaced apart at a distance from about 1.0 mm to about 2.0 mm.
19 . A pierce nut for attachment to a thin sheet of ultra-high strength metal comprising:
a generally cylindrical body having a central axis, a top surface and an annular-shaped bottom surface;
an internal threaded bore extending through the cylindrical body from the top surface to the bottom surface configured to receive a fastener;
a pilot portion coaxial with the cylindrical body and extending outward from the bottom surface; and
a plurality of radially spaced apart cavities recessed in the bottom surface and surrounding the pilot portion, wherein each cavity comprises opposing spaced apart sidewalls and a continuous base wall having a sloped portion that linearly increases in depth from a peripheral edge surface of the bottom surface toward the central axis and converging with a concave divot portion of an arcuate cross-section with a radius of about 0.1 mm to about 0.5 mm.
20 . The pierce nut according to claim 19 , wherein the plurality of cavities is from 11 cavities to 12 cavities.