Axial tension screw
DCFirst Claim
Patent Images
1. A fastener comprising:
- a root portion, the root portion having a leading end, a trailing end and an elongate axis extending therebetween; and
a single continuous thread formed on the root portion and extending between the leading end and the trailing end of the root portion, the thread having an outside diameter which, moving from the leading end toward the trailing end, increases over several revolutions, then decreases, then increases again, wherein the pitch of the thread measured between corresponding points on consecutive threads near the leading end is larger than the pitch of the threads near the trailing end.
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Abstract
A screw having a root and threads formed on the root. The screw is configured to generate and/or maintain axial compression between threads formed in leading and trailing sections of the screw either by virtue of pitch differential in the threads or the way in which the screw is installed.
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Citations
78 Claims
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1. A fastener comprising:
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a root portion, the root portion having a leading end, a trailing end and an elongate axis extending therebetween; and a single continuous thread formed on the root portion and extending between the leading end and the trailing end of the root portion, the thread having an outside diameter which, moving from the leading end toward the trailing end, increases over several revolutions, then decreases, then increases again, wherein the pitch of the thread measured between corresponding points on consecutive threads near the leading end is larger than the pitch of the threads near the trailing end. - View Dependent Claims (2, 3, 4, 6)
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5. The fastener of claim I further including a self-drilling tip disposed at the leading end of the root portion.
- 7. A screw comprising a leading section having a plurality of thread revolutions, a trailing section having a plurality of thread revolutions and an unthreaded intermediate section between the leading and trailing sections, the thread revolutions in the leading section having a greater average pitch and smaller average outside diameter than the thread revolutions in the trailing section, and where the outside diameter of the thread revolutions in the leading section generally increases toward the trailing section.
- 16. A screw comprising a leading end, a leading section proximal to the leading end and having a plurality of thread revolutions, a trailing end, a trailing section proximal the trailing end and having a plurality of thread revolutions, and a waist section having at least one thread revolution disposed between the leading and trailing sections, the thread revolutions in the leading section having a greater average pitch and smaller maximum outside diameter than the thread revolutions in the trailing section, and wherein the minimum outside diameter of the at least one thread revolution in the waist section is less than the maximum outside diameter of the thread revolutions in the leading section.
- 27. A screw comprising a leading section having a plurality of thread revolutions, a trailing section having a plurality of thread revolutions and an intermediate section between the leading section and the trailing section, the thread revolutions in the leading section having a greater average pitch and smaller maximum outside diameter than the thread revolutions in the trailing section, the intermediate section having a smaller average outside diameter than the leading or trailing sections and where the outside diameter of the thread revolutions in the leading section generally increases from revolution to revolution toward the trailing section.
- 46. A screw comprising a leading section having a plurality of thread revolutions, a trailing section having a plurality of thread revolutions and an intermediate section disposed between the leading section and the trailing section and having a plurality of thread revolutions, the outside diameter of the thread revolutions forming a surface of revolution about an elongate axis of the screw, the surface of revolution being convex in the transition from the leading section to the intermediate section and concave in the transition from the intermediate section to the trailing section, and wherein the thread revolutions in the leading section have a greater average pitch and smaller maximum outside diameter than the thread revolutions in the trailing section.
- 74. A screw comprising a leading section having a plurality of thread revolutions and a trailing section having a plurality of thread revolutions and forming a continuous extension of the thread revolutions of the leading section, the outside diameter of the thread revolutions forming a surface of revolution about an elongate axis of the screw, the surface of revolution being convex in the transition from the leading section to the trailing section, and wherein the thread revolutions in the leading section have a greater average pitch and smaller average outside diameter than the thread revolutions in the trailing section and the length of the leading section is less than the length of the trailing section, the screw further including a root portion and wherein there is a termination zone in the thread revolutions in the leading section in which the thread revolutions diminish from approximately the average outside diameter of the thread revolutions in the leading section down to a starting point on the root portion, and wherein the diameter of the root portion does not diminish substantially in the termination zone whereby the screw has a relatively blunt leading end.
Specification