Two piece tack rivets

Abstract

A two piece tack rivet includes a stem and a locking collar. The stem has a head at a first end, a grooved stem region extending from an opposing second end toward the first end, and a cylindrical section between the head and the grooved stem region. The cylindrical section includes a plurality of spin prevention embellishments such as knurls or spline-like surface textures. The cylin spin prevention embellishments may be adapted to provide positive engagement in a hole in a work piece. The locking collar is hollow and adapted to be deformably joined to the grooved stem region. The locking collar may include a flange adapted to bear against an adjacent surface of the work piece.

What is claimed is:  
     
         1 . A two piece tack rivet comprising: 
 a stem having a head at a first end, a grooved stem region extending from an opposing second end toward the first end, and a cylindrical section between the head and the grooved stem region, the cylindrical section including a plurality of spin prevention embellishments; and    a hollow locking collar adapted to be deformably joined to the grooved stem region.    
     
     
         2 . The two piece tack rivet of  claim 1 , wherein the plurality of spin prevention embellishments includes a plurality of spline-like surface textures.  
     
     
         3 . The two piece tack rivet of  claim 1 , wherein the plurality of spin prevention embellishments includes a plurality of knurls.  
     
     
         4 . The two piece tack rivet of  claim 1 , wherein the plurality of spin prevention embellishments are adapted to provide positive engagement in a hole in a work piece.  
     
     
         5 . The two piece tack rivet of  claim 1 , wherein the head of the stem includes a work piece facing surface having a plurality of outwardly projecting ridges.  
     
     
         6 . The two piece tack rivet of  claim 1 , wherein the head of the stem includes a work piece facing surface having a plurality of knurls.  
     
     
         7 . The two piece tack rivet of  claim 1 , wherein the head of the stem includes a central drill centering depression.  
     
     
         8 . The two piece tack rivet of  claim 1 , wherein the grooved stem region is terminated at the second end by a tapered stem tip.  
     
     
         9 . The two piece tack rivet of  claim 1 , wherein the stem is solid.  
     
     
         10 . The two piece tack rivet of  claim 1 , wherein the locking collar includes a flange adapted to bear against an adjacent surface of a work piece.  
     
     
         11 . A two piece tack rivet comprising: 
 a stem having a head at a first end, a grooved stem region extending from an opposing second end toward the first end, and a cylindrical section between the head and the grooved stem region, the cylindrical section including spin prevention means for preventing spinning of the stem in an outer work piece; and    locking means for deformable joining to the grooved stem region.    
     
     
         12 . The two piece tack rivet of  claim 1 , wherein the spin prevention means includes a spline-like surface texture.  
     
     
         13 . The two piece tack rivet of  claim 1 , wherein the spin prevention means includes a plurality of knurls.  
     
     
         14 . The two piece tack rivet of  claim 1 , wherein the spin prevention means is adapted to provide positive engagement in a hole in a work piece.  
     
     
         15 . The two piece tack rivet of  claim 1 , wherein the head of the stem includes a work piece facing surface having a plurality of outwardly projecting ridges.  
     
     
         16 . The two piece tack rivet of  claim 1 , wherein the head of the stem includes a work piece facing surface having a plurality of knurls.  
     
     
         17 . The two piece tack rivet of  claim 1 , wherein the head of the stem includes a central drill centering depression.  
     
     
         18 . The two piece tack rivet of  claim 1 , wherein the grooved stem region is terminated at the second end by a tapered stem tip.  
     
     
         19 . The two piece tack rivet of  claim 1 , wherein the stem is solid.  
     
     
         20 . The two piece tack rivet of  claim 1 , wherein the locking means includes a flange adapted to bear against an adjacent surface of a work piece.  
     
     
         21 . A two piece tack rivet comprising: 
 a solid stem having 
 a head at a first end,  
 a grooved stem region extending from an opposing second end toward the first end, and  
 a cylindrical section between the head and the grooved stem region, the cylindrical section including a plurality of knurls adapted to provide positive engagement in a hole in a work piece; and  
   a hollow locking collar adapted to be deformably joined to the grooved stem region, the locking collar including a flange adapted to bear against an adjacent surface of the work piece.