Thread roll dies

Abstract

The present invention is directed at an improved thread rolling die, comprising flat parallel longitudinal top and bottom edges, flat tapered die ends, and a vertical face that is used in producing the thread. Formed on the face is a series of parallel ridges which include a plurality of flanks positioned at a pre-determined angle. The ridges are complementary to the thread to be produced and are at an acute angle relative to the top and bottom edges. The ridges are configured for producing a thread helix when a blank is rolled between a set of dies. The thread roll dies have flat narrow surfaces at an angle of less than 60 degrees from the vertical face of the die, rather than being perpendicular to the longitudinal axes of the ridges. The top edge of the die leading to the ends of the vertical face of the die and leading away from the top surface of the die at a 60 degree angle. The ends of the die are positioned approximately 30 degrees from the perpendicular position to create smoother threads.

What is claimed is:  
     
         1 . A thread rolling die comprising: 
 a flat longitudinal top edge and a parallel flat longitudinal edge;    a vertical face having a series of parallel ridges, the ridges include a plurality of flanks positioned at a pre-determined angle, the ridges are positioned at an acute angle relative to the top and bottom edges and are configured for producing a thread helix; and    a stepped beveled surface which forms a part of the top edge is located between a top edge surface of the die and the vertical face, the stepped beveled surface is positioned at a pre-determined angle relative to the top edge surface, 
 wherein the ridges intersect the stepped beveled surface and have ends, the ends are positioned at a pre-determined angle to the top edge of the die and blend smoothly into substantially flat surfaces which extend to the top edge surface of the die such that the substantially flat surfaces are positioned at an angle less than 60 degree from the vertical face of the die.  
   
     
     
         2 . The thread rolling die of  claim 1  wherein the ends are leading away at a 60 degree angle from the top edge of the die.  
     
     
         3 . The thread rolling die of  claim 1  wherein the ends are approximately at a 30 degree angle from the top edge of the die.  
     
     
         4 . The thread rolling die of  claim 1  wherein the ridges are generally V-shaped in end elevation.  
     
     
         5 . The thread rolling die of  claim 1  wherein the ridges include a plurality of flanks each separated by a 60 degree angle.  
     
     
         6 . The thread rolling die of  claim 1  wherein the stepped beveled surface extends at a 5 degree angle with respect to the upwardly-facing flanks of the ridges that run out at the top edge surface.  
     
     
         7 . The thread rolling die of  claim 1  wherein the beveled surface blends with the flanks that it intersects.  
     
     
         8 . The thread rolling die of  claim 1  wherein the vertical dimension of the top edge surface is equal to at least twice a pitch of a thread to be produced.  
     
     
         9 . The thread rolling die of  claim 1  wherein the ridge ends are convexly rounded, with a compound curvature.  
     
     
         10 . The thread rolling die of  claim 1  wherein the stepped beveled surface is positioned at a pre-determined angle of 25 degrees from the top edge of the die.  
     
     
         11 . The thread rolling die of  claim 1  wherein the substantially flat surfaces are substantially narrow.  
     
     
         12 . The thread rolling die of  claim 1  wherein the substantially flat surfaces are transverse with respect to the ridges and are positioned at an angle less than 60 degree to a longitudinal axes of the ridges.  
     
     
         13 . The thread rolling die of  claim 1  wherein the ends are positioned at a pre-determined angle of less than 60 degrees to the top edge of the die.  
     
     
         14 . The thread rolling die of  claim 1  wherein the substantially flat surfaces are slightly curved and extend to the top edge surface of the die such that the substantially flat surfaces are positioned at an angle less than 60 degrees from the face of the die  
     
     
         15 . The thread rolling die of  claim 1  further having a first end and a second end tapered at approximately 10 degrees towards a central axis of the die.  
     
     
         16 . A moving thread rolling die, said moving die capable of producing less stress and strain in a thread transition area of a fastener and reducing substantial scrap during the manufacture of fasteners, said moving die comprising: 
 a longitudinal top edge having a length (A) and a longitudinal bottom edge having a base length (B), the longitudinal top edge and the longitudinal bottom edge are substantially parallel to each other;    a vertical face having a face length (D), which has a pre-determined number of ridges complementary to a thread to be produced, the vertical face having a tapered length (E) to permit a smooth engagement and disengagement of a fastener; and    a plurality of taper ends having a height (C).    
     
     
         17 . The thread rolling die of  claim 16  wherein the taper ends are tapered at approximately 10 degree towards a central axis of the die.  
     
     
         18 . A stationary thread rolling die, said stationary die capable of producing less stress and strain in a thread transition area of a fastener and reducing substantial scrap during the manufacture of fasteners, said stationary die comprising: 
 a longitudinal top edge having a length (F) and a longitudinal bottom edge having a base length (G), the longitudinal top edge and the longitudinal bottom edge substantially parallel to each other;    a vertical face having a face width (J), which has pre-determined number of ridges complementary to the thread to be produced, the vertical face having a tapered length (K) and another tapered length (L) at a pre-determined location to permit a smooth engagement and disengagement of a fastener; and    a plurality of taper ends having a height (C).    
     
     
         19 . The thread rolling die of  claim 18  wherein the longitudinal top edge has tapered ends, wherein depths of taper at both ends are adjusted to manufacture fasteners with less stress and strain and to reduce the manufacturing scrap.