Abstract: A patch application system is provided comprising a powder application booth. The powder application booth comprises a powder block to temporarily house the powder prior to ejection, a nozzle insert to guide the powder onto the screw, a support stand to adjust the powder block to the appropriate position relative to the screw for a desired patch location and size, a powder cup to deliver the powder to the powder block. A programmable logic controller electronically coupled to the micro air-switch valve controls the duration the air-switch valve remains open. The entire process may be automated by including a screw hopper to temporarily store a plurality of screws, a bowl feeder receiving the screws and delivering the screws to a rotating disk, wherein the rotating disk passes the screws through a heating element and presents the heated screws to the powder application booth.

Abstract: A patch application system is provided comprising a powder application booth. The powder application booth comprises a powder block to temporarily house the powder prior to ejection, a nozzle insert to guide the powder onto the screw, a support stand to adjust the powder block to the appropriate position relative to the screw for a desired patch location and size, a powder cup to deliver the powder to the powder block. A programmable logic controller electronically coupled to the micro air-switch valve controls the duration the air-switch valve remains open. The entire process may be automated by including a screw hopper to temporarily store a plurality of screws, a bowl feeder receiving the screws and delivering the screws to a rotating disk, wherein the rotating disk passes the screws through a heating element and presents the heated screws to the powder application booth.

Abstract: A self-locking threaded member which may be internally or externally threaded at least along a portion of its surface includes an aperture provided longitudinally along the axis of the member but spaced radially from the center thereof. The aperture is preferably located such that a portion thereof passes through adjacent flanks of the threads and includes a portion which is radially positioned to pass through the base of the valleys. The aperture receives a locking member in the form of a pin which extends axially of the fastener and is of a length to extend across at least two adjacent crests and is preferably spaced from the lead threads. The locking member operates as a wedge to cause an increase in the friction between the mating threads opposite the position of the locking element. Various forms of locking elements may be used, such as plastic or metal. Various configurations are disclosed as well as a relatively simple method to make the fastener.

Abstract: Thermoplastic polymer locking elements are formed on threaded fasteners to provide a range of self-locking torque characteristics. The thermoplastic resins are of the type that crystallize during cooling from the molten state.The crystallizable polymers are preferably applied in film form to preheated threaded fasteners. By correlation of the preheat temperature, the length of time during which the molten polymer is allowed to melt and flow onto the thread surfaces, and the rate of cooling of the assembly, the geometry of the locking element and the degree of crystallinity of the polymer are controlled.

Abstract: A self-locking fastener includes an externally threaded fastener element provided with an aperture which is off-center with respect to the axis of the fastener element. Received within the aperture is a locking element which may be of plastic, preferably a polyimide such as VESPEL, for use under high temperature conditions. The aperture is preferably round while the locking element is preferably square, for ease of fabrication, although metal locking elements may be used and the aperture may be of other shapes. The length of the locking element is coordinated and correlated with the major and minor diameters of the fastener such that the end faces of the locking element substantially occupy a significant portion of the valleys between adjacent crests, rather than matching the thread profile, in order to provide effective locking as required by certain designated specifications set forth herein.

Abstract: An apparatus for forming a self-locking patch type fastener which includes carrier means for moving a plurality of threaded metal fasteners along an arcuate path, clamping means associated with the carrier means to clamp the fasteners to the carrier means, movable resin transfer means having a fastener contact surface, and the transfer means being positioned to move the contact surface into contact with the fastener as the fastener is moved in arcuate path past the transfer means. The speed and direction of movement of the contact surface relative to the carrier means during contact between the contact surface and the fastener is such as to provide an even transfer of resin from the contact surface to deposit a plastic patch thereon. Unclamping means are positioned with respect to the carrier means to unclamp the threaded fasteners after deposit of the plastic patch thereon and conveyor means then convey the fasteners away from the carrier means.

Abstract: The present invention is an improvement in a machine described in U.S. Pat. No. 4,046,106 for applying a daub of liquid resin to the threads of a bolt-like fastener. In the unimproved machine the daub was applied by moving the fasteners tangentially to a disc-like applicator wheel. The improvement includes a number of notches in the circumferential edge of the applicator wheel. The fasteners engage the notches with the result that the patch of resin applied extends around the threaded fastener farther in the circumferential direction.

Abstract: An externally screw threaded fastener body is bored longitudinally to form a bore having a reduced inner axial portion and an outer axial portion of enlarged diameter and a noncircular mandrel is forced into the bore to expand the reduced inner portion thereof and thereby form at least one radially outwardly protruding lobe for local increase in the pitch diameter of the external screw thread. The fastener body may then again be drilled longitudinally, the final result being a fastener, at least a portion of which is tubular with a relatively thin resilient circumferential wall having at least one radially outward lobe.

Abstract: An apparatus for forming a self-locking patch type fastener which includes carrier means for moving a plurality of threaded metal fasteners along an arcuate path, clamping means associated with the carrier means to clamp the fasteners to the carrier means, movable resin transfer means having a fastener contact surface, and the transfer means being positioned to move the contact surface into contact with the fastener as the fastener is moved in an arcuate path past the transfer means. The speed and direction of movement of the contact surface relative to the carrier means during contact between the contact surface and the fastener is such as to provide an even transfer of resin from the contact surface to deposit a plastic patch thereon. Unclamping means are positioned with respect to the carrier means to unclamp the threaded fasteners after deposit of the plastic patch thereon and conveyor means then convey the fasteners away from the carrier means.

Abstract: For the production of screw fasteners with plastic patches thereon, the fasteners are preheated to a high temperature. Each heated fastener pauses at a processing station where a predetermined increment of a plastic strip is severed and dropped onto the hot fastener and as the plastic melts a pressure shoe forms the plastic to the curved cross-sectional configuration of the fastener. The fasteners are then quenched. For high production a number of the fasteners are processed simultaneously on each of the repeated cycles of operation. The apparatus is readily adjustable to handle fasteners of different sizes.