# US 2025/0084884 A1 · Fastening collars, multi-piece fasteners, and methods for fastening > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2025/0084884 A1 - Document ID: US20250084884A1 - Status: Published application - Kind: A1 - Application number: 18/580,242 - Filed: 2022-08-16 - Published: 2025-03-13 - Earliest claimed: 2021-08-19 - Assignees: Howmet Aerospace Inc. - Applicants: Howmet Aerospace Inc. - Inventors: Arnaud BRUNET - Web page: https://patentgrep.com/patent/US20250084884A1 ## CPC - F16B 19/05: Bolts fastening by swaged-on collars (F16B19/08 takes precedence) - F16B 5/04: by means of riveting (rivets F16B19/04) - F16B: DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING (couplings for transmitting rotation F16D) ## Abstract The present disclosure relates to fastening collars, multi-piece fasteners, and methods for fastening. A fastening collar comprises a first collar end, a second collar end, and an elongate portion intermediate the first collar end and the second collar end and defining a longitudinal axis of the fastening collar. The elongate portion comprises an external collar surface, an inner collar surface defining a collar cavity, and a groove on at least one of the external collar surface and inner collar surface. The groove extends a first distance along the longitudinal axis. ## Claims ### Claim 1 A multi-piece fastener comprising a pin configured to be at least partially received in the collar cavity of the fastening collar; and a fastening collar comprising: a first collar end; a second collar end; and an elongate portion intermediate the first collar end and the second collar end and defining a longitudinal axis of the fastening collar, wherein the elongate portion comprises an external collar surface, an inner collar surface defining a collar cavity, and a groove on at least one of the external collar surface and the inner collar surface, wherein the groove extends a first distance along the longitudinal axis, and wherein the groove is configured to engage a substantially smooth region of a shank of the pin during installation. ### Claim 2 (depends on 1) The multi-piece fastener of claim 1, wherein the groove is on at least the external collar surface of the elongate portion. ### Claim 3 (depends on 1) The multi-piece fastener of claim 1, wherein the groove is on at least the inner collar surface of the elongate portion ### Claim 4 (depends on 1) The multi-piece fastener of claim 1, wherein a wall thickness of the elongate portion at the groove is at least 10% less than an average wall thickness of the elongate portion. ### Claim 5 (depends on 1) The multi-piece fastener of claim 1, wherein a wall thickness of the elongate portion at the groove is at least 20% less than an average wall thickness of the elongate portion. ### Claim 6 (depends on 1) The multi-piece fastener of claim 1, wherein the groove is annular. ### Claim 7 (depends on 1) The multi-piece fastener of claim 1, wherein the first distance is at least 5% of the total length of the fastening collar. ### Claim 8 (depends on 1) The multi-piece fastener of claim 1, wherein the groove is offset at least 5% of the total length of the fastening collar from the second collar end. ### Claim 9 (depends on 1) The multi-piece fastener of claim 1, wherein the elongate portion further comprises a flange portion extending a second distance along the longitudinal axis. ### Claim 10 (depends on 1) The multi-piece fastener of claim 1, wherein the fastening collar is generally cylindrical. ### Claim 11 (depends on 1) The multi-piece fastener of claim 1, wherein the fastening collar comprises at least one of a metal, a metal alloy, and a composite. ### Claim 12 (canceled) ### Claim 13 (canceled) ### Claim 14 (depends on 1) The multi-piece fastener of claim 1, wherein the pin comprises a shank comprising at least one of an annular shoulder, a groove, a threaded region, and a substantially smooth region. ### Claim 15 (depends on 1) The multi-piece fastener of claim 1, wherein the multi-piece fastener is configured to be installed in a bore in a structure configured as at least one of an aerospace part or component, an automotive part or component, a transportation part or component, and a building and construction part or component. ### Claim 16 (depends on 1) The multi-piece fastener of claim 1, wherein the pin comprises a shank comprising a shank diameter in a range of 0.06 inch to 4 inches. ### Claim 17 (depends on 1) The multi-piece fastener of claim 1, wherein the pin further comprises a head portion. ### Claim 18 (depends on 1) The multi-piece fastener of claim 1, wherein the multi-piece fastener is at least one of a lockbolt and a blind fastener. ### Claim 19 A method for fastening, the method comprising: providing a multi-piece fastener comprising a fastening collar comprising a first collar end, a second collar end, and an elongate portion intermediate the first collar end and the second collar end and defining a longitudinal axis of the fastening collar, wherein the elongate portion comprises an external collar surface, an inner collar surface defining a collar cavity, and a groove on at least one of the external collar surface and the inner collar surface, wherein the groove extends a first distance along the longitudinal axis, and a pin configured to be at least partially received in the collar cavity of the fastening collar, the pin comprises a shank comprising a generally smooth region, and a second region comprising at least one of an annular shoulder, a groove, and a threaded region; inserting the first pin end of the pin into a bore of a structure and the collar cavity, wherein the groove is positioned over the generally smooth region; and forcibly contacting the elongate portion of the fastening collar with a contact surface of an installation tool, thereby forcibly contacting the structure with the second collar end of the fastening collar and deforming the elongate portion onto the shank of the pin, including deforming the groove. ### Claim 20 (depends on 19) The method of claim 19, wherein deforming the elongate portion onto the shank comprises swaging with an anvil of the installation tool.