Airbus Operations Gmbh

Richard Dobbin

David Liversage

Matthew Cross

Thomas Monaghan

Julien Assemat

Ben Humphrys

Anthony Dowson

Julien Legrand

Matthew Webster

Guy Tothill

Darren Crew

Mark Scarrott

John Stuckey

A spark containment cap for enclosing an end of a fastener protruding from a structure, the enclosed body having a base and a cover portion, the cover portion extending from the base, the base providing an adhering surface for adhering the spark containment cap to a structure, and the base and the cover portion together forming a cavity within the enclosed body inside which the end of a fastener can be enclosed.

Spark containment cap

A spark containment cap for forming a sealed cavity around an end of a fastener protruding from a structure is disclosed having a cap body with an annular base terminating at a rim which surrounds an opening into an air cavity arranged to enclose the end of the fastener. An annular sealing volume extends around the rim arranged to receive an annular bead of a curable sealing material around the opening into the cavity to provide a seal between the cap body and the structure to seal a volume of gas within the cavity. An engaging feature is configured to engage with the end of the fastener to prevent rotation of the fastener relative to the cap when the end of the fastener is received by the cap. A fastening system, a joint, an aircraft and a method of securing a fastener and a spark containment cap to a structure are also disclosed.

A spark containment cap forms a sealed cavity around an end of a fastener protruding from a structure. The cap has a cap body defining an air cavity enclosing the end of the fastener. The cap body includes an annular base () terminating at a base rim () surrounding an opening into the air cavity. An annular skirt of the cap provides an annular sealing volume extending around the base rim to receive an annular bead of a curable sealing material around the opening into the cavity to provide a seal between the cap body and the structure to seal a volume of gas within the cavity. The cap body includes a cap upper to receive the end of the fastener. The cap upper () is positionable so that an axis of the cap upper is offset from an axis of the annular skirt ().

A method of joining a first workpiece to a second workpiece is disclosed including securing a spark containment cap to the first workpiece, the cap comprising an electrically insulating washer and a cap body defining an air cavity. Once the cap has been secured, a tail of a fastener is inserted into the air cavity through the second workpiece, the first workpiece and the washer. Upon tightening the fastener, the tail of the fastener urges the washer against the first workpiece and the first and second workpiece are thereby clamped between the washer and a head of the fastener so as to form a joint. Advantageously, it has been found that forming a joint in this manner can help to better protect the joint from the effects of electrical arcing.

A cap is disclosed having a collar portion with three or more contact regions arranged to contact the end of a fastener around which the collar portion is provided, the collar portion having a lobed shape in cross-section such that an outwardly projecting lobe extends between each neighbouring pair of contact regions. An advantage of this lobed arrangement is that the cap can tolerate relatively large manufacturing tolerances at the fastener end. The cap may be for fitting over a nut or fastener head, with the contact regions of the cap being arranged to contact corresponding contact regions on a cylindrical collar base portion of the nut or fastener head. The diameter of this cylindrical collar portion may not be well controlled, so that the manufacturing tolerance is high. The lobed shape of the cap base ensures that the contact regions will always provide a good frictional engagement with the nut, whether the cylindrical collar is undersized, oversized, or at its nominal diameter.

Lobed nut cap

A cap for forming a sealed cavity around an end of a fastener is disclosed. The cap has a cap body with an annular base terminating at a base rim which surrounds an opening into a central cavity. The cap also has an annular skirt providing an annular pocket between the skirt and the base. An inlet hole is provided in the skirt which is in fluid communication with the annular pocket. A protuberance protrudes in the annular pocket and faces the inlet hole to promote a flow of sealant injected through the inlet hole to flow annularly around the annular pocket.

Cap with sealant flow path

A cap for forming a sealed cavity around an end of a fastener protruding from a surface of a structure is disclosed. The disclosure relates to a spark prevention cap. The cap has an annular base with an annular base terminating at a base rim. The base rim surrounds an opening into a central cavity for receiving the end of the fastener. The base rim lies in a base rim plane around at least a majority of a circumference of the annular base. An annular skirt provides an annular pocket in which a sealant material is received. A biasing configuration is configured to positively bias the base rim against the surface of the structure.

A cap configured for providing a sealed cavity around an end of a fastener and a method of bonding a cap to a structural member in which a contact adhesive is provided for fixing the cap to the structural member and a curable sealant is provided for bonding the cap to the substrate.

Cap for a fastener

A cap for forming a sealed cavity around an end of a fastener protruding from a structure. The cap has: a cap body with an annular base terminating at a rim which surrounds an opening into a central cavity; an annular skirt providing an annular pocket between the skirt and the base; and an inlet hole in the skirt. The inlet hole is in fluid communication with the pocket and arranged to interconnect with a sealing material injection device to provide a flow of sealing material through the skirt via the inlet hole into the pocket. An outlet is also provided in the skirt. The outlet is in fluid communication with the pocket and arranged to enable air to escape the pocket through the skirt via the outlet hole as the sealing material flows from the inlet hole into the pocket.

Cap with injected sealant

A self-sealing fixing element is disclosed having a body with a bearing surface, and a bore with an opening in the bearing surface. A curable sealant layer is carried by the bearing surface and encircles the opening in the bearing surface. The curable sealant layer is formed from a sealant material which cures when exposed to atmosphere. A barrier layer overlays the curable sealant layer and can break apart when the fixing element is installed in order to expose the sealant layer to atmosphere. The curable sealant layer has a thickness which decreases away from the bore, and the barrier layer has a thickness which increases away from the bore.

Self-sealing fixing element

A cap for forming a sealed cavity around an end of a fastener is disclosed having a cap body with an annular base terminating at an inner cap rim which surrounds an opening into a central cavity and lies in an inner cap plane around a majority of a circumference of the annular base. A skirt provides an annular pocket between the skirt and the annular base. The skirt has a first part which is integrally formed with the cap body from a first material and terminates at an edge, and a second part which is formed from a second material and extends from the edge of the first part of the skirt to a skirt rim which lies in or below the inner cap plane around a majority of a circumference of the skirt.

The present invention proposes a cap having a collar portion with three or more contact regions arranged to contact the end of a fastener around which the collar portion is provided, the collar portion having a lobed shape in cross-section such that an outwardly projecting lobe extends between each neighboring pair of contact regions. An advantage of this lobed arrangement is that the cap can tolerate relatively large manufacturing tolerances at the fastener end. For example, the cap may be for fitting over a nut or fastener head, with the contact regions of the cap being arranged to contact corresponding contact regions on a cylindrical collar base portion of the nut or fastener head. The diameter of this cylindrical collar portion may not be well controlled, so that the manufacturing tolerance is high. The lobed shape of the cap base ensures that the contact regions will always provide a good frictional engagement with the nut, whether the cylindrical collar is undersized, oversized, or at its nominal diameter.

A cap for forming a sealed cavity around one end of a fastener, the cap having a two-piece construction comprising an outer cap member and an inner cap member. A quantity of sealant is provided between the inner and outer cap members which, upon installation of the cap, is urged to flow between the inner and outer cap members and collect at the base of the outer cap member, to form a bead of sealant around the circumference of the cap, sufficient to adhere the cap to the structure when the sealant cures. A plurality of channels are provided between the inner and outer cap members to facilitate the flow of sealant.

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Bristol, United Kingdom

Richard Dobbin