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

A fastener which can be installed into at least one workpiece by swaging or torquing methods, 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 male thread which is sufficiently strong to have a swage collar of a softer material swaged onto it without appreciable damage to the threads, 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 smaller than the second diameter of the threaded shank portion, wherein a swage collar or a female threaded device which is intended to be engaged with the threaded shank portion of the fastener fits over the pin tail portion without any interference;
• and
• a breakneck groove positioned between the threaded shank portion and the pin tail portion and substantially centered about the longitudinal axis, the breakneck groove having,
• a first conically tapered surface which tapers distally from the threaded shank portion toward the longitudinal axis of the fastener,
• a second conically tapered surface which tapers proximally from the pin tail portion toward the longitudinal axis of the fastener,
• a substantially circumferential intersection between the first and second conically tapered surfaces, and
• a radius at the intersection of the first conically tapered surface and the second conically tapered surface, the radius having a controlled dimension, and
• wherein the breakneck groove is controlled to ensure that the breakneck groove includes a lower tensile strength than any other portion of the fastener and 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.

A method of installing a fastener into at least one workpiece, 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 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 male thread which is sufficiently strong to have a swage collar of a softer material swaged onto it without appreciable damage to the threads and 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 means for a tool to engage the pin tail portion and pull the fastener in tension and having a third diameter which is smaller than the second diameter of the threaded shank portion, wherein a swage collar which is intended to be engaged with the threaded shank portion of the fastener fits over the pin tail portion without any interference, and
• 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 controlled to ensure that the breakneck groove includes a lower tensile strength than any other portion of the fastener and 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 the fourth diameter of the breakneck groove and the strength of the fastener material in the region of the breakneck groove;
• providing at least one workpiece, the at least one workpiece having a hole therethrough which provides a clearance fit with the smooth shank portion of the fastener;
• inserting the pin tail portion of the fastener into the hole within the at least one workpiece from a first side of the at least one workpiece and advancing the fastener distally until the pin tail portion protrudes from a surface on a second side of the at least one workpiece and a distal surface on the head of the fastener contacts a surface on the first side of the at least one workpiece;
• providing a swage collar having a substantially smooth interior surface which provides a clearance fit between the swage collar and the threaded shank portion;
• sliding the swage collar proximally over the pin tail portion and threaded shank portion of the fastener until the swage collar is positioned proximate the second side of the at least one workpiece;
• engaging the pin tail portion with a tool;
• pulling the fastener distally in tension through the use of the tool;
• pushing the swage collar proximally against the second side of the at least one workpiece through the use of the tool;
• swaging the swage collar onto the threaded shank portion of the fastener through the use of the tool until the swage collar substantially fills the threads on the threaded shank portion;
• and
• increasing tension at the pin tail portion of the fastener through the use of the tool until the preset range of tension has been attained and the fastener severs at the breakneck groove.

A method of installing a fastener into at least one workpiece, 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 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 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 means for a tool to engage the pin tail portion and pull the fastener in tension and having a third diameter which is smaller than the second diameter of the threaded shank portion, wherein a female threaded device which is intended to be engaged with the threaded shank portion of the fastener fits over the pin tail portion without any interference, and
• 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 controlled to ensure that the breakneck groove includes a lower tensile strength than any other portion of the fastener and 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 the fourth diameter of the breakneck groove and the strength of the fastener material in the region of the breakneck groove;
• providing at least one workpiece, the at least one workpiece having a hole therethrough which provides a clearance fit with the smooth shank portion of the fastener;
• inserting the pin tail portion of the fastener into the hole within the at least one workpiece from a first side of the at least one workpiece and advancing the fastener distally until the pin tail portion protrudes from a surface on a second side of the at least one workpiece and a distal surface on the head of the fastener contacts a surface on the first side of the at least one workpiece;
• providing a female threaded device;
• sliding the female threaded device proximally over the pin tail portion;
• engaging the pin tail portion with a tool;
• pulling the fastener distally in tension through the use of the tool;
• preventing the fastener from turning through the use of the tool;
• torquing the female threaded device onto the threaded shank portion through the use of the tool until a desired torsional load is attained;
• and
• increasing tension at the pin tail portion of the fastener through the use of the tool until the preset range of tension has been attained and the fastener severs at the breakneck groove.

A method of installing a fastener into at least one workpiece, 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 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 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 means for a tool to engage the pin tail portion and pull the fastener in tension and having a third diameter which is smaller than the second diameter of the threaded shank portion, wherein a female threaded device which is intended to be engaged with the threaded shank portion of the fastener fits over the pin tail portion without any interference, and
• 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 controlled to ensure that the breakneck groove includes a lower tensile strength than any other portion of the fastener and 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 the fourth diameter of the breakneck groove and the strength of the fastener material in the region of the breakneck groove;
• providing at least one workpiece, the at least one workpiece having a hole therethrough which provides an interference fit with the smooth shank portion of the fastener;
• inserting the pin tail portion of the fastener into the hole within the at least one workpiece from a first side of the at least one workpiece and advancing the fastener distally until the pin tail portion protrudes from a surface on a second side of the at least one workpiece;
• engaging the pin tail portion with a tool;
• pulling the smooth shank portion of the fastener distally into the hole within the at least one workpiece through the use of the tool which is engaged with the pin tail portion until a distal surface on the head of the fastener contacts a surface on the first side of the at least one workpiece;
• increasing tension at the pin tail portion of the fastener through the use of the tool until the preset range of tension has been attained and the fastener severs at the breakneck groove;
• providing a female threaded device;
• and
• torquing the female threaded device onto the threaded shank portion through the use of the tool until a desired torsional load is attained.