Self-aligning sleeved protruding head fasteners with electromagnetic effect protection features
AssigneeThe Boeing Company
InventorsRichard P. Whitlock, Peter A. Coronado, Sean D. Morden, Randall A. Rogers, Julie M. Drexler, John R. Porter, Jeffry G. Bickford
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Abstract
A fastener system for composite structure provides electromagnetic energy protection by incorporating a self-aligning head (SAH) fastener having a head with a spherical engaging surface and a shank extending from the head for insertion through a hole in a composite structure and a self-aligning self sealing (SASS) washer having a throat receiving the shank and a spherical mating surface interfacing with the spherical engaging surface of the head.
Claims25
A fastener system for composite structure providing electromagnetic energy protection comprising:
- a self-aligning head (SAH) fastener having a head with a spherical engaging surface and a shank extending from the head for insertion through a hole in a composite structure;
- and,
- a self-aligning self sealing (SASS) washer having a throat receiving the shank and a spherical mating surface interfacing with the spherical engaging surface of the head.
A method for installation of an EME protection fastener system comprising:
- identifying a hole in a surface of a composite structure for insertion of a fastener;
- inserting a body of a sleeve in the hole with a flange contacting the surface of the structure;
- inserting a seal in a seal relief in an SASS washer;
- positioning the SASS washer over the hole and sleeve flange with a bottom land in contact with the sleeve flange;
- inserting a SAH fastener into the sleeve;
- expanding the sleeve for an interference fit between both the sleeve body and SAH fastener shank and the sleeve body and composite hole;
- interfacing a spherical engaging surface on a head of the SAH fastener with a spherical mating surface on the SASS washer to accommodate angular offset in the SAH fastener due to non-orthogonality of the hole;
- and,
- torqueing a internally threaded fastener on threads in an end of the SAH fastener.
A method for fabrication of a EME protection fastener system comprising:
- providing a SAH fastener shank;
- providing a taper on the shank;
- creating threads on a first end of the shank;
- providing a head having a spherical engaging surface on a second end of the shank;
- providing a wrenchable counter-bore in the shank for torqueing of the SAH fastener;
- providing the SAH fastener with a dielectric coating;
- providing a SASS washer with a throat to receive the shank of the SAH fastener;
- providing the SASS washer with a spherical mating surface to receive the engaging surface of the SAH fastener head;
- providing a flare in the throat to accommodate angular displacement of the shank;
- providing a seal relief to accommodate a seal;
- providing a bottom land on the SASS washer inboard of the seal relief for contacting a sleeve flange;
- providing a dielectric coating on the SASS washer excluding the bottom land;
- and,
- providing a sleeve having a flange to contact the bottom land of the SASS washer and a body for insertion into a structural hole and to receive the shank of the SAH fastener.
Dependencies are inferred from the claim text.