Light weight fastener for use on interference fits in automation

Abstract

A fastener for installation into an interference fit hole within a structure. The fastener may be installed through automated installation methods. The fastener includes an enlarged protruding head at a proximal end of the fastener. Distal the head is a substantially cylindrical shoulder portion. The shoulder portion is coated with a lubricant to facilitate insertion of the shoulder portion into the interference fit hole within the structure. A threaded portion having a male thread is positioned distal to the shoulder portion. An aperture having a curved shape and extending into the fastener is positioned on a distal face of the fastener. The aperture may taper proximally into the fastener.

What is claimed:  
     
         1 . A fastener, comprising: 
 an enlarged protruding head positioned at a proximal end of the fastener and substantially centered about a longitudinal axis of the fastener;    a substantially cylindrical shoulder portion positioned adjacent and distal to the head and substantially centered about the longitudinal axis, the shoulder portion having a first diameter;    a lubricant coating composition on a surface of the shoulder portion;    a threaded portion positioned adjacent and distal to the shoulder portion and substantially centered about the longitudinal axis, the threaded portion including a male thread and having a second diameter smaller than the first diameter of the shoulder portion; and    an aperture positioned on a distal face of the fastener and substantially centered about the longitudinal axis, the aperture having a substantially curved shape in a cross section substantially perpendicular to the longitudinal axis of the fastener and extending proximally into the fastener.    
     
     
         2 . The fastener of  claim 1 , wherein the first diameter of the shoulder portion is configured to provide an interference fit with a hole in a structure into which it is to be installed.  
     
     
         3 . The fastener of  claim 1 , wherein the length of the shoulder portion is sufficient to protrude from a surface on a second side of a structure while a distal surface of the head is in contact with a surface on a first side of the structure.  
     
     
         4 . The fastener of  claim 1 , wherein the length of the shoulder portion is sized so that the shoulder portion does not protrude from a surface on a second side of the structure while a distal surface of the head is in contact with a surface on a first side of the structure.  
     
     
         5 . The fastener of  claim 1 , wherein a distance across the periphery at the opening of the aperture is about fifty percent to about seventy-five percent of the diameter of the threaded portion.  
     
     
         6 . The fastener of  claim 1 , wherein a depth of the aperture is about one to about two times the distance across the periphery at the opening of the aperture.  
     
     
         7 . The fastener of  claim 1 , wherein the curved shape of the aperture comprises a substantially circular shape having a diameter.  
     
     
         8 . The fastener of  claim 7 , wherein the diameter at the opening of the aperture is about fifty percent to about seventy-five percent of the diameter of the threaded portion.  
     
     
         9 . The fastener of  claim 1 , wherein the aperture extends substantially longitudinally into the fastener.  
     
     
         10 . The fastener of  claim 1 , wherein the aperture tapers into the fastener.  
     
     
         11 . The fastener of  claim 10 , wherein the taper of the aperture includes a substantially conical shape.  
     
     
         12 . The fastener of  claim 10 , wherein the taper of the aperture includes a substantially parabolic shape.  
     
     
         13 . The fastener of  claim 1 , wherein the lubricant coating composition comprises polytetrafluoroethylene.  
     
     
         14 . A fastener, comprising: 
 an enlarged protruding head positioned at a proximal end of the fastener and substantially centered about a longitudinal axis;    a substantially cylindrical shoulder portion positioned adjacent and distal to the head and substantially centered about the longitudinal axis, the shoulder portion having a first diameter and being configured to provide an interference fit with a hole in a structure into which it is to be installed;    a lubricant coating composition on a surface of the shoulder portion, the lubricant coating composition including polytetrafluoroethylene;    a threaded portion positioned adjacent and distal to the shoulder portion and substantially centered about the longitudinal axis, the threaded portion including a male thread and having a second diameter smaller than the first diameter of the shoulder portion; and    an aperture positioned on a distal face of the fastener and substantially centered about the longitudinal axis, the aperture extending proximally and substantially longitudinally into the fastener to form a cavity having a substantially curved shape in a cross section substantially perpendicular to the longitudinal axis of the fastener, a distance across the periphery at the opening of the aperture being about fifty percent to about seventy-five percent of the diameter of the threaded portion, the depth of the cavity being about one to about two times the distance across the perimeter at the opening of the aperture.    
     
     
         15 . The fastener of  claim 14 , wherein the curved shape of the cross section of the cavity comprises a substantially circular shape having a diameter.  
     
     
         16 . A fastener, comprising: 
 an enlarged protruding head positioned at a proximal end of the fastener and substantially centered about a longitudinal axis;    a substantially cylindrical shoulder portion positioned adjacent and distal to the head and substantially centered about the longitudinal axis, the shoulder portion having a first diameter and being configured to provide an interference fit with a hole in a structure into which it is to be installed;    a lubricant coating composition on a surface of the shoulder portion, the lubricant coating composition including polytetrafluoroethylene;    a threaded portion positioned adjacent and distal to the shoulder portion and substantially centered about the longitudinal axis, the threaded portion including a male thread and having a second diameter smaller than the first diameter of the shoulder portion; and    an aperture positioned on a distal face of the fastener and substantially centered about the longitudinal axis, the aperture extending proximally into the fastener to form a cavity having a substantially curved shape in a cross section substantially perpendicular to the longitudinal axis of the fastener, the cavity tapering into the fastener, a distance across a periphery at the opening of the aperture being about fifty percent to about seventy-five percent of the diameter of the threaded portion, the depth of the cavity being about one to about two times the distance across the perimeter at the opening of the aperture.    
     
     
         17 . The fastener of  claim 16 , wherein the curved shape of the cross section of the cavity comprises a substantially circular shape having a diameter.  
     
     
         18 . The fastener of  claim 16 , wherein the taper of the aperture includes a substantially conical shape.  
     
     
         19 . The fastener of  claim 16 , wherein the taper of the aperture includes a substantially parabolic shape.  
     
     
         20 . A method for installing a fastener into a hole in a structure, comprising: 
 providing a fastener having, 
 an enlarged protruding head positioned at a proximal end of the fastener and substantially centered about a longitudinal axis,  
 a substantially cylindrical shoulder portion positioned adjacent and distal to the head and substantially centered about the longitudinal axis, the shoulder portion having a first diameter and being configured to provide an interference fit with the hole in the structure,  
 a lubricant coating composition on a surface of the shoulder portion, the lubricant coating composition including polytetrafluoroethylene,  
 a threaded portion positioned adjacent and distal to the shoulder portion and substantially centered about the longitudinal axis, the threaded portion including a male thread and having a second diameter smaller than the first diameter of the shoulder portion, and  
 an aperture positioned on a distal face of the fastener and substantially centered about the longitudinal axis, the aperture having a substantially curved shape in a cross section substantially perpendicular to the longitudinal axis of the fastener and extending proximally and substantially longitudinally into the fastener, a distance across a periphery at the opening of the aperture being about fifty percent to about seventy-five percent of the diameter of the threaded portion, a depth of the aperture being about one to about two times the size of the distance across the periphery at the opening of the aperture;  
   providing a structure having a hole therethrough;    inserting the threaded portion of the fastener into the hole in the structure from a first side of the structure;    advancing the fastener distally through the hole until a distal surface on the head of the fastener contacts a surface on the first side of the structure;    retaining the fastener within the hole through compressive forces from the hole being applied to the shoulder portion of the fastener;    providing a female threaded device; and    torquing the female threaded device onto the threaded portion of the fastener.    
     
     
         21 . The method of  claim 20 , wherein advancing the fastener comprises pushing the head of the fastener distally toward the structure until the distal surface on the head contacts the surface on the first side of the structure.  
     
     
         22 . The method of  claim 20 , wherein advancing the fastener comprises: 
 advancing the fastener distally until the threaded portion protrudes through a surface on a second side of the structure;    engaging the threaded portion with a tool; and    applying a distally directed pulling force to the fastener through the use of the tool until the distal surface on the head contacts the surface on the first side of the structure.    
     
     
         23 . A method for installing a fastener into a hole in a structure, comprising: 
 providing a fastener having, 
 an enlarged protruding head positioned at a proximal end of the fastener and substantially centered about a longitudinal axis,  
 a substantially cylindrical shoulder portion positioned adjacent and distal to the head and substantially centered about the longitudinal axis, the shoulder portion having a first diameter and being configured to provide an interference fit with the hole in the structure,  
 a lubricant coating composition on a surface of the shoulder portion, the lubricant coating composition including polytetrafluoroethylene,  
 a threaded portion positioned adjacent and distal to the shoulder portion and substantially centered about the longitudinal axis, the threaded portion including a male thread and having a second diameter smaller than the first diameter of the shoulder portion, and  
 an aperture positioned on a distal face of the fastener and substantially centered about the longitudinal axis, the aperture extending proximally into the fastener to form a cavity having a substantially curved shape in a cross section substantially perpendicular to the longitudinal axis of the fastener and tapering into the fastener, a distance across a periphery at the opening of the aperture being about fifty percent to about seventy-five percent of the diameter of the threaded portion, the depth of the cavity being about one to about two times the distance across the periphery at the opening of the aperture;  
   providing a structure having a hole therethrough;    inserting the threaded portion of the fastener into the hole in the structure from a first side of the structure;    advancing the fastener distally through the hole until a distal surface on the head of the fastener contacts a surface on the first side of the structure;    retaining the fastener within the hole through compressive forces from the hole being applied to the shoulder portion of the fastener;    providing a tapered pin;    inserting the tapered pin into the aperture;    applying force in a proximal direction to the aperture via the tapered pin;    providing a female threaded device; and    torquing the female threaded device onto the threaded portion of the fastener.    
     
     
         24 . The method of  claim 23 , wherein advancing the fastener comprises pushing the head of the fastener distally toward the structure until the distal surface on the head contacts the surface on the first side of the structure.  
     
     
         25 . The method of  claim 23 , wherein advancing the fastener comprises: 
 advancing the fastener distally until the threaded portion protrudes through a surface on a second side of the structure;    engaging the threaded portion with a tool; and    applying a distally directed pulling force to the fastener through the use of the tool until the distalsurface on the head contacts the surface on the first side of the structure.