Pull sterm hi-lite pin with pull groove for swaging collars

Abstract

A fastener for installation into a workpiece which may be installed by either a swaging operation or a torquing operation. The fastener includes an enlarged protruding head which is proximal to a substantially cylindrical smooth shank portion. A threaded shank portion positioned distal to the smooth shank portion includes a male thread which is sufficiently strong to have a swage collar swaged onto it. Distal to the threaded shank portion is a pin tail portion having a surface which is configured to engage a tool. Positioned between the threaded shank portion and the pin tail portion is a breakneck groove having a lower tensile strength than any other portion of the fastener. The tensile strength of the breakneck groove is controlled such that the fastener severs within the breakneck groove when a preset range of tension is applied to the pin tail portion by the tool.

1 . In a fastener which can be installed into at least one workpiece for combination with the at least one workpiece, the at least one workpiece having a first side, a second side, and a hole extending through the at least one workpiece from the first side to the second side, the improvement in the fastener comprising:
 an enlarged protruding head positioned at a proximal end of the fastener and substantially centered about a longitudinal axis;   a substantially cylindrical smooth shank portion positioned adjacent and distal to the head and substantially centered about the longitudinal axis, the smooth shank portion having a first diameter;   a threaded shank portion positioned distal to the smooth shank portion and substantially centered about the longitudinal axis, the threaded shank portion including a standard male thread configured to receive a female threaded nut, said male thread being sufficiently strong to have a swage collar swaged onto it without appreciable damage to the male thread, the male thread having a second diameter smaller than the first diameter of the smooth shank portion;   a pin tail portion positioned distal to the threaded shank portion and substantially centered about the longitudinal axis, the pin tail portion including a plurality of circumferentially extending annular grooves and having a third diameter which is sufficiently small that a swage collar which is intended to be engaged with the threaded shank portion of the fastener may slide over the pintail without any interference;   a breakneck groove having a fourth diameter which is smaller than the third diameter of the pin tail portion, the breakneck groove being positioned between the threaded shank portion and the pin tail portion, and substantially centered about the longitudinal axis, the breakneck groove being configured such that the fastener will sever at the breakneck groove when a preset range of tension is applied to the fastener at the pin tail portion; and   an unthreaded swage collar providing a clearance fit between the swage collar and the pin tail portion, breakneck groove portion, and the threaded shank portion and configured to be swaged onto the threaded shank portion, and wherein said swage collar fits over the pin tail portion, breakneck groove portion, and the threaded shank portion without any interference.   
     
     
         2 . The fastener of  claim 1 , wherein said fastener is heated treated such that the male thread is stronger than a material of the unthreaded swage collar. 
     
     
         3 . The fastener of  claim 1 , wherein the strength of the breakneck groove is controlled through the fourth diameter of the breakneck groove and the strength of the fastener material in the region of the breakneck groove. 
     
     
         4 . The fastener of  claim 1 , further comprising a substantially circumferential intersection in the breakneck groove having a radius of a controlled dimension. 
     
     
         5 . The fastener of  claim 1  wherein the third diameter is smaller than the second diameter. 
     
     
         6 . The fastener of  claim 1  wherein the breakneck groove has a distally tapering portion terminating at a land of the pin tail portion. 
     
     
         7 . The fastener of  claim 6  wherein the land of the pin tail portion adjacent the breakneck groove has an axial thickness equal to a thickness of a second land on the pin tail portion. 
     
     
         8 . The fastener of  claim 1  wherein the breakneck groove has a proximally conically tapered surface which tapers proximally from the pin tail portion toward the longitudinal axis of the fastener and a distally conically tapered surface which tapers distally from the threaded shank portion toward the longitudinal axis of the fastener 
     
     
         9 . The fastener of  claim 1  wherein the unthreaded swage collar includes a substantially smooth interior surface. 
     
     
         10 . A fastener which can be installed into at least one workpiece, comprising:
 an enlarged protruding head positioned at a proximal end of the fastener and substantially centered about a longitudinal axis;   a substantially cylindrical smooth shank portion positioned adjacent and distal to the head and substantially centered about the longitudinal axis, the smooth shank portion having a first diameter;   a threaded shank portion positioned distal to the smooth shank portion and substantially centered about the longitudinal axis, the threaded shank portion including a standard male thread configured to receive a female threaded nut, said male thread being sufficiently strong to have a swage collar swaged onto it without appreciable damage to the male thread, the male thread having a second diameter smaller than the first diameter of the smooth shank portion;   a pin tail portion positioned distal to the threaded shank portion and substantially centered about the longitudinal axis, the pin tail portion including a plurality of circumferentially extending annular grooves for engagement with a tool to pull the fastener in tension and having a third diameter which is sufficiently small that a swage collar which is intended to be engaged with the threaded shank portion of the fastener may slide over the pintail without any interference;   a breakneck groove positioned between the threaded shank portion and the pin tail portion and substantially centered about the longitudinal axis, and   wherein the breakneck groove is configured to ensure that the fastener will sever at the breakneck groove when a preset range of tension is applied to the fastener at the pin tail portion, the tensile strength of the breakneck groove being controlled through a fourth diameter of the breakneck groove and the strength of the fastener material in the region of the breakneck groove, the fourth diameter being smaller than the third diameter of the pin tail portion; and   an unthreaded swage collar providing a clearance fit between the swage collar and the pin tail portion, breakneck groove portion, and the threaded shank portion and configured to be swaged onto the threaded shank portion, and wherein said swage collar fits over the pin tail portion, breakneck groove portion, and the threaded shank portion without any interference.   
     
     
         11 . The fastener of  claim 10 , further comprising a substantially circumferential intersection between the proximally and distally conically tapered surfaces. 
     
     
         12 . The fastener of  claim 11 , wherein the substantially circumferential intersection between the proximally and distally conically tapered surfaces has a radius with a controlled dimension. 
     
     
         13 . The fastener of  claim 10  wherein the breakneck groove has a distally tapering portion terminating at a land of the pin tail portion. 
     
     
         14 . The fastener of  claim 13  wherein the land of the pin tail portion adjacent the breakneck groove has an axial thickness equal to a thickness of a second land on the pin tail portion. 
     
     
         15 . The fastener of  claim 10  wherein the breakneck groove has a proximally conically tapered surface which tapers proximally from the pin tail portion toward the longitudinal axis of the fastener and a distally conically tapered surface which tapers distally from the threaded shank portion toward the longitudinal axis of the fastener 
     
     
         16 . The fastener of  claim 10  wherein the unthreaded swage collar includes a substantially smooth interior surface.