Sps Technologies, LLC

Standard Pressed Steel Co.

Richard C Landt

Warren F Dahl

A self-locking fastener having a bearing surface comprising a plurality of sets of serrations arranged to penetrate a workpiece such that while a resistance to the loosening of the fastener from the workpiece is created the marring of the workpiece surface is minimized. Use of the fastener is particularly advantageous if the workpiece consists of soft materials such as cast-aluminum or non-heat treated carbon steels. Each set of serration, when viewed as a profile, includes a downwardly inclined surface, a relatively deeper serration and a relatively shallower intermediate serration. The intermediate serration controls the depth of the penetration into a workpiece.

Vibration resistant fasteners

A self-locking fastener having a bearing surface comprising a plurality of sets of serrations arranged to penetrate a workpiece such that, while a resistance to the loosening of the fastener from the workpiece is created, the marring of the workpiece surface is minimized. Use of the fastener is particularly advantageous if the workpiece consists of soft materials such as cast-aluminum or non-heat treated carbon steels. Each set of serration, when viewed as a profile, includes a downwardly inclined surface, a relatively deeper serration and a relatively shallower intermediate serration. The intermediate serration controls the depth of the penetration into a workpiece.

A blind fastener assembly includes a pin, an expander and a sleeve. The pin and expander may include, in one configuration, mating threads for drawing the sleeve axially over the expander toward the blind side of a workpiece, or the pin may be a pull-type wherein the portion of the pin opposite from the blind side end has pull grooves which are adapted to be gripped by a conventional pull gun. The sleeve is a tubular member having a portion of varying radial wall thickness between the ends thereof. The expander extends through aligned holes in the workpieces and has a tapered nose surface proximate the reduced thickness portion of the sleeve. When an axial force is exerted on the pin, the sleeve is forced over the tapered nose surface on the expander toward the blind side of the workpiece and is expanded in diameter. When the leading edge of the sleeve contacts the blindside workpiece surface, a radially outwardly extending bulb forms at the varying thickness portion in order to accommodate variations in the thickness of the workpieces. The diameter of the bulb is dependent on the overall joint thickness, with a larger diameter bulb forming for a maximum joint thickness and a smaller diameter bulb being formed for a minimum joint thickness. At a predetermined axial position of the pin relative to the expander, a reduced diameter breakneck portion of the pin fractures at a predetermined torque or load, leaving a properly tensioned joint.

Blind fastener

A blind fastener assembly includes a pin, an expander and a sleeve. The pin and expander may include, in one configuration, mating threads for drawing the sleeve axially over the expander toward the blind side of a workpiece, or the pin may be a pull-type wherein the portion of the pin opposite from the blind side end has pull grooves which are adapted to be gripped by a conventional pull gun. The expander extends through aligned holes in the workpiece and has a tapered nose surface at the blind side end adjacent a reduced thickness cylindrical portion which extends axially to a stop shoulder. The shoulder provides a transition to a normal thickness cylindrical portion which extends through the workpiece holes. The sleeve is a tubular member with a portion of its length having a normal radial thickness and a portion having a reduced radial thickness. In a preferred embodiment, the reduced radial thickness portion comprises a reduced outer diameter over a portion of its axial length and a corresponding counter-bore along the same portion of axial length adjacent the end of the sleeve proximate the tapered nose surface on the expander. When an axial force is exerted on the pin, the reduced thickness portion of the sleeve is forced over the tapered nose surface on the expander and expanded in diameter until it contacts the shoulder on the expander. Continued axial force on the pin causes an outwardly extending bulb to form in the reduced thickness portion of the sleeve at the shoulder. Further axial pulling causes a portion of the sleeve to shear off and remain lodged between the reduced thickness surface of the expander and the shoulder while the formed bulb is further expanded and pulled over the normal thickness surface of the expander outer diameter until it clamps against the surface of the workpiece material.

Blind fastener assembly

A blind fastener assembly includes, in one embodiment a pin, an expander and a sleeve. The pin and expander may include, in one configuration, mating threads for drawing the sleeve axially over the expander toward the blind side of a workpiece, or the pin may be a pull-type wherein the portion of the pin opposite from the blind side end has pull grooves which are adapted to be gripped by a conventional pull gun. The sleeve is a tubular member with a portion of its length having a normal radial thickness and a portion having reduced radial thickness comprising a reduced outer diameter over a portion of its axial length and a counter-bore along the same axial length adjacent one end of the sleeve. The expander extends through aligned holes in the workpieces and has a tapered nose surface proximate the reduced thickness portion of the sleeve. When an axial force is exerted on the pin, the reduced thickness portion of the sleeve is forced over the tapered nose surface on the expander toward the blind side of the workpiece and is expanded in diameter. The tapered surface of the expander also deforms and expands the inner diameter of the normal thickness portion of the sleeve where it meets the counter-bore, and when the leading edge of the sleeve contacts the blindside workpiece surface, an optimum shaped, maximum diameter bulb forms in the reduced thickness portion of the sleeve against the blindside workpiece surface. When the bulb is fully formed, a reduced diameter breakneck portion of the pin fractures at a predetermined torque or load, leaving a properly tensioned joint.

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Souderton, PA, United States of America

Richard C Landt