Self-attaching female fastener element, sealed fastener and panel assembly and method of forming same
A self-attaching female fastener such as a pierce nut having an annular pilot, an annular flange surrounding the pilot and an annular groove in the flange bearing surface surrounding the pilot, wherein the bottom wall of the groove includes wedge-shaped recesses dividing the groove bottom wall into segments having parallel sides defined by the adjacent wedge-shaped recesses and the inclined outer wall of the pilot is deformed radially during installation to entrap and compact panel metal in the groove forming a sealed secure installation having improved push-off and anti-rotation strength.
1. A self-attaching female fastener element for attachment to a metal panel, comprising:
an annular pilot portion having a bore extending through an annular end face of said pilot portion;
an annular flange portion surrounding said pilot portion having a planar annular bearing face generally parallel to a plane of said end face of said pilot portion;
an annular groove in said annular bearing face of said flange portion surrounding said pilot portion including an annular groove bottom wall, a groove inner side wall adjacent said pilot portion and an outer groove wall;
said annular groove bottom wall including a plurality of circumferentially spaced generally wedge-shaped recesses extending from adjacent said groove outer side wall to adjacent said groove inner side wall defining radial segments of said groove bottom wall therebetween, each radial segment having a top face integral with said outer groove wall and radial side walls extending from said groove bottom wall to a bottom wall of said recesses; and
said groove outer side wall inclined inwardly at an acute angle from said groove bottom wall toward said pilot portion overlying said top face of said radial segments integral with said groove outer side wall, whereby said metal panel deformed against said top faces of said radial segments is deformed radially outwardly beneath said inclined groove outer side wall.
2. The self-attaching female fastener element as defined in claim 1 , wherein said bottom wall of said recesses is planar between said radial segments.
3. The self-attaching female fastener element as defined in claim 2 , wherein said planar bottom wall of said recesses is parallel to said planar annular bearing face of said annular flange portion.
4. The self-attaching female fastener element as defined in claim 1 , wherein said groove outer side wall is frustoconical having a continuous frustoconical surface.
5. The self-attaching female fastener element as defined in claim 1 , wherein said radial segments of said radial groove bottom wall have a circumferential width greater than a circumferential width of said recesses.
6. A self-attaching female fastener element for attachment to a metal panel, comprising:
an annular pilot portion having a bore extending through an annular end face of said pilot portion;
an annular flange portion surrounding said pilot portion having a planar annular bearing face generally parallel to a plane of said end face of said pilot portion;
an annular groove in said planar annular bearing face of said flange portion surrounding said pilot portion, including an annular groove bottom wall, a groove inner side wall adjacent said pilot portion and a groove outer side wall;
said annular groove bottom wall including a plurality of circumferentially spaced generally wedge-shaped recesses extending from adjacent to said groove outer side wall to adjacent said groove inner side wall including a planar recess bottom wall extending parallel to said planar annular bearing face of said flange portion;
said recesses defining radial segments of said groove bottom wall therebetween each having a top face integral with said groove outer side wall and radial side walls extending from said planar recess bottom wall to said groove bottom wall; and
said groove outer side wall inclined inwardly at an acute angle from said groove bottom wall toward said pilot portion overlying said top faces of said radial segments of said annular groove bottom wall integral with said groove outer side wall, whereby said metal panel deformed against said top faces of said radial segments integral with said groove outer side wall is deformed radially beneath said inclined groove outer side wall.
7. The self-attaching female fastener element as defined in claim 6 , wherein all of said radial segments of said bottom wall of said annular groove are integral with said groove outer side wall.
8. The self-attaching female fastener element as defined in claim 6 , wherein said groove outer side wall is frustoconical having a continuous frustoconical surface.
9. The self-attaching female fastener element as defined in claim 6 , wherein said radial segments of said annular groove bottom wall have a circumferential width greater than a circumferential width of said recesses.