Self-attaching female fastener element, sealed fastener and panel assembly and method of forming same

Abstract

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, 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 generally planar annular bearing face generally parallel to the plane of said end face of said pilot portion;    an annular groove in said 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 inclined from said annular groove bottom wall toward said pilot portion defining a restricted opening in said annular groove adjacent said annular bearing face of said flange portion; and    said annular groove bottom wall including a plurality of circumferentially spaced wedge-shaped recesses extending generally radially from said inner groove wall to said outer groove wall, each recess having a generally planar recess bottom wall spaced below the plane of said annular groove bottom wall and opposed linear recess side walls extending generally perpendicular to said annular groove bottom wall, and said recess side walls diverging outwardly from said inner groove side wall to said outer groove side wall, whereby said wedge-shaped recesses are narrower adjacent said pilot portion then adjacent said annular flange portion.    
     
     
         2 . The self-attaching female fastener element as defined in  claim 1 , wherein said annular groove bottom wall between adjacent wedge-shaped recesses is defined by parallel recess side walls of adjacent wedge-shaped recesses.  
     
     
         3 . The self-attaching female fastener element as defined in  claim 1 , wherein said recess side walls are defined by parallel lines tangent to a circle generated from said bore, wherein said recesses are wedge-shaped and said groove bottom wall between adjacent wedge-shaped recesses is defined by said parallel lines.  
     
     
         4 . The self-attaching female fastener element as defined in  claim 1 , wherein said inner groove side wall is inclined outwardly from adjacent said groove bottom wall toward said inner groove wall.  
     
     
         5 . A self-attaching female fastener element, comprising: 
 an annular pilot portion having a bore extending through a planar annular end face of said pilot portion;    an annular flange portion surrounding said pilot portion having a generally planar annular bearing face generally parallel to the plane of said planar annular 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, an inner groove side wall adjacent said pilot portion inclined outwardly from adjacent said groove bottom wall and an outer groove wall inclined from said annular groove bottom wall toward said pilot portion, wherein said inner and outer groove side walls define a restricted opening of said annular groove adjacent said annular bearing face; and    said annular groove bottom wall including a plurality of circumferentially spaced generally radial wedge-shaped recesses each having a recess bottom wall spaced below the plane of said annular groove bottom wall and linear recess side walls, wherein said recess side walls are defined by parallel lines tangent to a circle generated from a central axis of said bore, whereby said recess side walls on opposed sides of said recess diverge outwardly from adjacent said pilot portion to adjacent said flange portion and said recess side walls on opposed sides of said groove bottom wall between adjacent recesses are parallel.    
     
     
         6 . The self-attaching female fastener element as defined in  claim 5 , wherein said recess side walls are generally perpendicular to said groove bottom wall.  
     
     
         7 . The self-attaching female fastener element as defined in  claim 5 , wherein said recess bottom walls are planar.  
     
     
         8 . The self-attaching female fastener element as defined in  claim 5 , wherein said recesses extend from said inner groove side wall to said outer groove side wall.  
     
     
         9 . A method of attaching a self-attaching female fastener element to a metal panel, said self-piercing female fastener element including an annular pilot portion having a planar end face and a bore extending through said pilot portion through said planar end face, an annular flange portion surrounding said pilot portion having a generally planar annular bearing face generally parallel to the plane of said end face of said pilot portion, and an annular groove in said annular bearing face of said flange portion surrounding said pilot portion having an annular groove bottom wall, an inclined groove side wall adjacent said pilot portion inclined outwardly from adjacent said groove bottom wall and an inclined outer groove wall inclined from said annular groove bottom wall toward said pilot portion defining a restrictive opening of said annular groove adjacent said bearing face of said flange portion, and said annular groove bottom wall including a plurality of circumferentially spaced wedge-shaped recesses each including a recess bottom wall spaced below the plane of said annular groove bottom wall and opposed recess side walls extending generally perpendicular to said annular groove bottom wall, wherein said recess side walls diverge outwardly such that said wedge-shaped recesses are narrower adjacent said pilot portion then adjacent said annular flange portion, said method comprising the following steps: 
 driving said end face of said pilot portion against a metal panel, piercing an opening through said metal panel and receiving said pilot portion through said opening in said panel;    driving an annular portion of said panel surrounding said opening against said annular groove bottom wall and against said recess bottom walls;    deforming said panel portion radially beneath said inclined inner and outer side walls and substantially filling said wedge-shaped recesses; and    deforming an outer portion of said end face of said pilot portion radially outwardly and axially against said panel portion sealing said self-attaching female fastener element on said panel.    
     
     
         10 . The method of attaching a female fastener element to a metal panel as defined in  claim 9 , wherein said recess side walls extend generally perpendicular to said annular bearing face of said flange portion, said method including deforming said panel portion against said recess side walls.  
     
     
         11 . A self-attaching female fastener element and panel assembly, comprising: 
 said female fastener element including 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 generally planar annular bearing face generally parallel to the plane of said end face of said pilot portion, and an annular groove in said annular bearing face of said flange portion surrounding said pilot portion including a groove bottom wall, an inclined inner groove side wall adjacent said pilot portion inclined outwardly from said groove bottom wall and an inclined outer groove side wall inclined from adjacent said annular groove bottom wall toward said pilot portion defining a restricted opening of said annular groove adjacent said bearing face of said flange portion and said annular groove bottom wall including a plurality of circumferentially spaced generally radial wedge-shaped recesses each having a recess bottom wall spaced below the plane of said annular groove bottom wall and opposed linear recess side walls extending generally perpendicular to said annular groove bottom wall, wherein said recess side walls diverge outwardly from adjacent said inner groove side wall to said outer groove side wall;    a metal panel having a first portion supported on said bearing face of said flange portion and a second portion deformed into said annular groove and said wedge-shaped recesses against said groove bottom wall, said recess bottom wall, said recess side walls and beneath said inclined inner and outer groove walls; and    an annular outer portion of said pilot portion deformed radially outwardly and against said second portion of said panel sealing said self-attaching female fastener element on said panel.    
     
     
         12 . The self-attaching female fastener element and metal panel assembly as defined in  claim 11 , wherein said annular groove bottom wall between adjacent wedge-shaped recesses is defined by parallel said recess side wall of adjacent wedge-shaped recesses.  
     
     
         13 . The self-attaching female fastener element and metal panel assembly as defined in  claim 11 , wherein said recess side walls are defined by parallel lines tangent to a circle generated from a central axis of said bore, whereby said recesses are wedge-shaped and said groove bottom wall between adjacent wedge-shaped recesses is generally rectangular.  
     
     
         14 . The self-attaching female fastener element and metal panel assembly as defined in  claim 11 , wherein said recess bottom walls are planer and parallel to said groove bottom wall.