Washer assembly with seal for lightning-protection fasteners and method of use

• Main Authors: Dessalegn, Haftom Y, Coronado, Peter Apolonio, Morden, Sean Dennis
• Format: Patent
• Language: English
• Published: 11.05.2021
• Subjects: AIRCRAFT; ARRANGEMENTS OR MOUNTING OF POWER PLANTS OR PROPULSIONTRANSMISSIONS IN AIRCRAFT; AVIATION; BLASTING; COSMONAUTICS; DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS ORMACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS,CLIPS, WEDGES, JOINTS OR JOINTING; ENGINEERING ELEMENTS AND UNITS; EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLYING SUITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVEFUNCTIONING OF MACHINES OR INSTALLATIONS; HEATING; LIGHTING; MECHANICAL ENGINEERING; PARACHUTES; PERFORMING OPERATIONS; THERMAL INSULATION IN GENERAL; TRANSPORTING; WEAPONS

A method of protecting an air vehicle against lightning strikes includes inserting a fastener through a hole in conjoined structures, the fastener defining an axis along its length and having a threaded end and a sleeve, and installing a washer assembly over the threaded end and the sleeve, the washer assembly having a metallic washer and a polymer seal radially inward of the metallic washer. The seal includes a lower seal portion defining a counter-bore, and an upper seal portion extending axially from the lower seal portion. The method includes installing a counter-bored nut on the threaded end, and applying torque to the nut to compress the lower seal portion against a surface of the conjoined structures and around the sleeve at the counter-bore of the seal, and to compress the upper seal portion of the seal into a counter-bore of the nut and around the threaded end.