Self-penetrating fastening rivet

Abstract

A rivet capable of self-piercing at least one sheet of material and becoming embedded in one of such sheets, generally consisting of a head section and a shank section formed integrally with the head section, wherein the head section includes an upwardly and outwardly curved side wall surface extending from the shank section to an upper portion of the head section, and the shank section includes a recess in a lower end thereof, with the lower end of the shank section having a peripheral cutting edge sufficient to penetrate such material.

We claim:  
     
         1 . A rivet capable of self-piercing a plurality of sheets of materials and becoming embedded in one of said sheets comprising: a head section; and a shank section formed integrally with said head section; wherein said head section includes an upwardly and outwardly curved side wall surface extending from said shank section to a point proximate an upper surface of said head section, and said shank section includes a recess in a lower end thereof, said lower end of said shank section having a peripheral cutting edge sufficient to penetrate said material.  
     
     
         2 . A rivet according to  claim 1  wherein said head section includes an upwardly and inwardly curved side wall surface extending from said point to the upper surface of said head section.  
     
     
         3 . A rivet according to  claim 1  wherein said head section is provided with an uninterrupted planar end surface.  
     
     
         4 . A rivet according to  claim 1  wherein said shank section is provided with a cylindrical exterior surface.  
     
     
         5 . A rivet according to  claim 4  wherein said head section is provided with an uninterrupted planar surface disposed perpendicularly relative to the axis of said cylindrical surface.  
     
     
         6 . A rivet according to  claim 1  wherein said recess extends into said head section.  
     
     
         7 . A rivet according to  claim 1  wherein said recess includes a cylindrical surface portion.  
     
     
         8 . A rivet according to  claim 1  wherein said recess includes a curved bottom surface.  
     
     
         9 . A rivet according to  claim 1  wherein the depth of said recess is less than a thickness of said sheets of material.  
     
     
         10 . A rivet according to  claim 1  wherein said rivet is capable of self-piercing at least two sheets of material and the depth of said recess is greater than a first of said sheets penetrated by said rivet.  
     
     
         11 . A rivet according to  claim 1  wherein said recess includes a conical surface.  
     
     
         12 . A rivet according to  claim 11  wherein an included angle of said conical surface is within the range of 25° and 120°.  
     
     
         13 . A rivet according to  claim 11  wherein said conical surface is slightly convex.  
     
     
         14 . A rivet according to  claim 1  wherein said shank section includes a cylindrical exterior surface and said recess includes a conical surface cooperating with said cylindrical surface to provide a circular cutting edge.  
     
     
         15 . A rivet according to  claim 1  wherein an outer end of said recess is provided with a beveled surface.  
     
     
         16 . A rivet according to  claim 15  wherein said beveled surface is annular.  
     
     
         17 . A rivet according to  claim 15  wherein said beveled surface is slightly convex.  
     
     
         18 . A rivet according to  claim 1  wherein said rivet is formed of a material harder than the material of said sheets penetrated by said rivet.  
     
     
         19 . A rivet according to  claim 1  wherein said rivet and said sheets are formed of metals.  
     
     
         20 . A rivet according to  claim 1  wherein said rivet and said sheets are formed of plastic materials.