Lisi Aerospace

Alexandre Berthou

Martial Broucke

Florent Verdier

Charles Pham

Christophe Payard

A fastener for assembling at least two structural elements having an aperture, may have a fastener comprising an enlarged head () and a shank () exhibiting, prior to fitting, an outside diameter (D) greater than an inside diameter (D) of the aperture, and a locking portion comprising a screw thread or annular grooves. The fastener further comprises a lubricating sacrificial ring () on the exterior surface of the fastener, extending at least between a distal end of the shank and a proximal end of the locking portion, said ring having, before the fastener is fitted into the structure, an outside diameter greater than a diameter of the aperture. The sacrificial ring comprises a polymer resin forming a matrix encapsulating dispersant molecules and oil molecules. The fastener assembly may apply to the assembly of aircraft structures.

Fastener with lubricating ring for interference fitting, and assembly method using such a fastener

The object of the invention is a cap to lubricate an inner wall of a perforation going through at least two elements of the structure. The cap comprises a tubular body and at least one lubricant reserve, and before installation in the structure said cap has a largest external diameter larger than an internal diameter (D) of the perforation, and the cap lubricates the internal surface of the perforation when its largest external diameter is radially compressed by a wall of the perforation. The invention also concerns a fastener comprising this type of cap, and an interference assembly process for the fastener equipped with the cap. The invention is applicable to the assembly of aircraft structures.

Lubricating cap, fastener comprising this type of cap and interference assembly process

A control ring and a method of using a control ring on fasteners can be used to verify a headed fastener having a band coating a fastener shaft. The ring comprises a cylindrical tubular body extending along an axis of revolution (B) and two opposite extremities. A first extremity includes two adjacent arc segments, each arc segment having an end wall extending in a plane perpendicular to the axis of revolution (B) of the ring, the planes of the two walls not being one and the same and axially offset from the first extremity. Each arc segment comprises at least one side wall extending over a radial plane going through the axis of revolution (B) of the ring. The width of an arc segment allows verifying a minimum band width, and the width of the two arc segments allows verifying a maximum band width on the fastener.

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Bois-Colombes, France

Alexandre Berthou