Self-attaching female fastener

1. A self-attaching nut for attachment to a panel, comprising:

a central pilot portion having a bore therethrough and a generally cylindrical outer surface;

a flange portion surrounding said outer surface of said pilot portion including i. an annular groove surrounding said pilot portion having a substantially V-shaped bottom wall, the annular groove extending radially outwardly from said outer surface of said pilot portion and ii. a generally planar panel support surface surrounding said annular groove extending substantially perpendicular to an axis of said bore; and

a plurality of circumferentially spaced radial ribs on or in said panel support surface of said flange portion extending into said annular groove, but spaced from said outer surface of said pilot portion, wherein said radial ribs are convex, projecting from said panel support surface having radial side faces and a top spaced above said panel support surface.

2. The self-attaching nut as defined in claim 1 , wherein said radial ribs are triangular in cross-section having radial side faces and a rounded top surface.

3. The self-attaching nut as defined in claim 1 , wherein said self-attaching nut further includes circumferentially spaced concave radial ribs.

4. The self-attaching nut as defined in claim 3 , wherein said circumferentially spaced concave radial ribs are channel-shaped having side walls and a bottom wall.

5. The self-attaching nut as defined in claim 1 , wherein said flange portion has a rectangular outer surface.

6. The self-attaching nut as defined in claim 5 , wherein said ribs extend to said rectangular outer surface of said flange portion.

7. The self-attaching nut as defined in claim 1 , wherein said flange portion has a square outer surface.

8. The self-attaching nut as defined in claim 7 , wherein said flange portion of said self-attaching nut includes a back face opposite said ribs having two pair of transverse parallel grooves adapted to receive frangible connector elements interconnecting a plurality of said self-attaching fasteners in side to side relation.

9. The self-attaching nut as defined in claim 1 , wherein said substantially V-shaped bottom wall of said annular groove is defined by said outer surface of said pilot portion and an inclined outer surface extending upwardly to said panel support surface.

10. The self-attaching nut as defined in claim 9 , wherein said substantially V-shaped bottom wall includes an arcuate surface between said outer surface of said pilot portion and said inclined outer surface of said annular groove.

11. A self-attaching nut for attachment to a panel, comprising:

a central pilot portion having a bore therethrough and a generally cylindrical outer surface;

a flange portion surrounding said outer surface of said pilot portion including i. an annular groove surrounding said pilot portion having a substantially V-shaped bottom wall, the annular groove extending radially outwardly from said outer surface of said pilot portion and ii. a generally planar panel support surface surrounding said annular groove extending substantially perpendicular to an axis of said bore;

a plurality of circumferentially spaced radial ribs on or in said panel support surface of said flange portion extending into said annular groove, but spaced from said outer surface of said pilot portion, wherein said radial ribs are concave having a bottom wall spaced below said panel support surface of said flange portion; and

circumferentially spaced convex radial ribs.

12. The self-attaching nut as defined in claim 11 , wherein said convex radial ribs have a triangular tangential cross-section.

13. The self-attaching nut as defined in claim 11 , wherein said convex radial ribs extend above a surface of said panel support surface and extend into said annular groove, but are spaced from said outer surface of said pilot portion.

14. A self-attaching nut for attachment to a panel, comprising:

a central pilot portion having a bore therethrough and a substantially cylindrical outer surface;

a flange portion surrounding said outer surface of said pilot portion including an annular groove surrounding said pilot portion having a substantially V-shaped bottom wall defined by said outer surface of said pilot portion and an outer surface inclined outwardly to a substantially planar panel support surface surrounding said annular groove; and

a plurality of circumferentially spaced convex radial ribs projecting from said panel support surface and extending into said outer surface of said annular groove.

15. The self-attaching nut as defined in claim 14 , wherein said convex radial ribs have a generally triangular cross-section including radial relatively inclined side faces projecting from said panel support surface.

16. The self-attaching nut as defined in claim 14 , wherein said self-attaching nut further includes circumferentially spaced concave radial ribs.

17. The self-attaching nut as defined in claim 16 , wherein said concave radial ribs are channel-shaped having side walls and a planar bottom wall.

18. The self-attaching nut as defined in claim 14 , wherein said flange portion has a square outer surface and includes a back face opposite said ribs having two pair of transverse parallel grooves adapted to receive frangible connector elements for interconnecting a plurality of self-attaching fasteners in side to side relation.