The Boeing Company

Hollis B Merrell

Louis A Champoux

Albert L Hametner

Brian R Trethewy

An improved interference fit, fatigue-rated pin-type, nondeformable fastener and joints formed thereby are disclosed in countersunk flush head and protruding flat head embodiments, each characterized by a straight interference fit shank with a lead-in convex shoulder adjacent its threaded end operable to cold work the wall material of the straight fastener hole during fastener insertion, and with the shank progressively expanded in a concave curvilinear profile to its head end starting at a location preferably intermediate the ends of the shank. Curvature of the expansion profile fairs smoothly at relatively large radius into the straight intermediate portion of the shank. At its opposite end, the expansion profile curvature merges into a relatively sharp curvature of very small radius (i.e., of the order of 1% of the first and larger radius) that fairs smoothly into the lower face of the fastener head. Fatigue failures and corrosion problems in the fastener hole wall material starting at the hole entrance, and in some instances problems with warpage of a structural member caused by fastener installation are substantially avoided by the improved fastener.

Fatigue resistant fastener and method of manufacturing joints therewith

An automatic fastener selection apparatus for sensing the composite thickness of a plurality of workpieces, determining which one of a plurality fastener sizes is appropriate for joining the workpieces together, and generating a dispensing signal representing the appropriate fastener size. Sensing apparatus provides a signal which is a function of the composite thickness of the workpieces, and this signal is processed by a selection circuit. The selection circuit generates an output signal in response to the signal from the sensing apparatus, and this output signal represents only one of a plurality of different fastener sizes. A triggering circuit then receives the output signal and generates the dispensing signal in response thereto. The apparatus may include a switching mechanism associated with the sensing apparatus and cooperating with the triggering circuit to generally synchronize the updating of the output signal and the generation of the dispensing signal with the completion of a thickness sensing operation. The apparatus may further include circuitry for facilitating the calibration of the selection circuit and a visual display for indicating the output signal, and the selection circuit may include enabling circuitry responsive both to the switching mechanism and to a manually-operable switch for enabling the triggering circuit.

Fastener selection system

A process for seating a lockbolt with a positioned collar, swaging the collar onto the seated lockbolt and breaking off the pintail all in one operation. A single source of hydraulic power pulls a nose piece with gripper jaws to seat the lockbolt and to break off the pintail, and to move an anvil in the opposite direction to swage a collar onto the seated lockbolt. A combination air and hydraulic system sequences these steps.

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Renton, WA, United States of America

Hollis B Merrell