# US 12,111,124 B1 · Pivot pin with installation aperture > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,111,124 B1 - Document ID: US12111124B1 - Status: Granted - Kind: B1 - Application number: 18/093,973 - Filed: 2023-01-06 - Granted: 2024-10-08 - Earliest claimed: 2023-01-06 - Assignees: Aero Precision Inc. - Applicants: Aero Precision, LLC - Inventors: Dustin Yearicks; Kirk Foreman - Web page: https://patentgrep.com/patent/US12111124B1 ## CPC - F41A 11/00: Assembly or disassembly features; Modular concepts; Articulated or collapsible guns (F41A3/64, F41A19/10 - F41A19/15, F41A21/48, F41A25/26 take precedence) - F16B 21/125: {radially resilient or with a snap-action member, e.g. elastic tooth, pawl with spring, resilient coil or wire} - F41A 3/66: Breech housings or frames; Receivers - F41A: FUNCTIONAL FEATURES OR DETAILS COMMON TO BOTH SMALLARMS AND ORDNANCE, e.g. CANNONS; MOUNTINGS FOR SMALLARMS OR ORDNANCE - 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 Embodiments are directed toward a pivot pin for a coupling an upper receiver of a firearm to a lower receiver of the firearm. In some embodiments, the pivot pin includes a head and a shaft that extends from the head. In some embodiments, the shaft defines a detent-retention channel and an installation aperture opposite the channel from the head. In some embodiments, the channel is configured to receive a detent and to enable the pivot pin to slide between a locked configuration and an unlocked configuration. In some embodiments, the installation aperture is configured to receive a tool that extends through the shaft, thereby urging the detent into a detent recess in the lower receiver while the shaft covers the detent recess in the lower receiver. Accordingly, the installation aperture facilitates reducing the likelihood that the detent escapes from the detent recess during installation of the pivot pin. ## Claims ### Claim 1 A pivot pin for a coupling an upper receiver of a firearm to a lower receiver of the firearm, the pivot pin comprising: a head; and a shaft that extends from the head, the shaft defining a detent-retention channel that extends along a first side the shaft, the installation aperture is spaced apart from the channel, the shaft defining an installation aperture opposite the channel from the head and extending through the first side of the shaft, the channel being configured to receive a detent and to enable the pivot pin to slide relative to the detent in the channel between a locked configuration and an unlocked configuration, the installation aperture being configured to receive a tool that extends through the shaft and to enable the detent to be urged by the tool into a detent recess in the lower receiver while the shaft covers the detent recess in the lower receiver and while the tool extends through the shaft, whereby the installation aperture in the shaft facilitates reducing a likelihood that the detent escapes from the detent recess in the lower receiver during installation of the pivot pin in the lower receiver. ### Claim 2 (depends on 1) The pivot pin of claim 1, wherein the installation aperture has an inner diameter that is at least as large as an outer diameter of the detent, the installation aperture being configured to enable insertion of the detent into the detent recess in the lower receiver while the pivot pin covers the detent recess in the lower receiver by inserting the detent through the installation aperture in the shaft of the pivot pin, whereby the installation aperture facilitates installation of the pivot pin in the lower receiver without using the pivot pin to overcome a bias of a spring in the detent recess in the lower receiver. ### Claim 3 (depends on 1) The pivot pin of claim 1, wherein the installation aperture has an inner diameter that is smaller than an outer diameter of the detent. ### Claim 4 (depends on 3) The pivot pin of claim 3, wherein the installation aperture has a retention portion with a diameter at least as great as the outer diameter of the detent, the retention portion being configured to retain the detent in the installation aperture while the pivot pin covers the detent recess in the lower receiver during installation of the pivot pin until the tool urges the detent into the detent recess in the lower receiver, whereby the installation aperture in the shaft facilitates increased control over the detent during installation of the pivot pin. ### Claim 5 (depends on 1) The pivot pin of claim 1, wherein the channel has a proximate end portion proximate to the head and a distal end portion distal to the head, the shaft defining a removal aperture in the distal end portion of the channel, the removal aperture being configured to receive the tool that extends through the shaft and to enable the detent to be urged by the tool out of the channel while the tool extends through the shaft, the removal aperture having an inner diameter that is smaller than an outer diameter of the detent, whereby the removal aperture facilitates preventing the detent from escaping the channel until the tool is inserted through the removal aperture. ### Claim 6 (depends on 5) The pivot pin of claim 5, wherein the installation aperture has an inner diameter that is greater than the inner diameter of the removal aperture. ### Claim 7 (depends on 5) The pivot pin of claim 5, wherein the installation aperture has an inner diameter that is substantially the same as the inner diameter of the removal aperture. ### Claim 8 (depends on 5) The pivot pin of claim 5, wherein the shaft defines a main floor of the channel and a ramp coupled to the main floor of the channel and to the removal aperture, the main floor of the channel extending from the proximate end portion of the channel to the distal end portion of the channel, whereby the ramp facilitates transitioning the pivot pin relative to the detent from the unlocked configuration to the locked configuration with reduced force applied to the pivot pin. ### Claim 9 (depends on 8) The pivot pin of claim 8, wherein the pivot pin defines a detent-retention recess in the proximate end portion of the channel and a ramp coupled to the main floor of the channel and to the detent-retention recess, whereby the ramp facilitates transitioning the pivot pin relative to the detent from the locked configuration to the unlocked configuration with reduced force applied to the pivot pin. ### Claim 10 A pin, comprising: a head; and a shaft that extends from the head, the shaft defining a detent-retention channel that extends along the shaft, the shaft defining an installation aperture opposite the channel from the head, the channel being configured to receive a detent and to enable the pin to slide relative to the detent in the channel between a locked configuration and an unlocked configuration, the installation aperture extending entirely through the shaft, wherein the installation aperture has an inner diameter that is smaller than an outer diameter of the detent and at least as large as an outer diameter of a tool, whereby the installation aperture in the shaft facilitates simplifying installation of the pin. ### Claim 11 (depends on 10) The pin of claim 10, wherein the installation aperture has a retention portion with a diameter at least as great as the outer diameter of the detent, the retention portion being configured to retain the detent in the installation aperture while the pin covers the recess until the tool urges the detent into the recess, whereby the installation aperture in the shaft facilitates increased control over the detent. ### Claim 12 (depends on 10) The pin of claim 10, wherein the channel has a proximate end portion proximate to the head and a distal end portion distal to the head, the shaft defining a removal aperture in the distal end portion of the channel, the removal aperture being configured to receive a tool that extends through the shaft to urge the detent out of the channel, the removal aperture having an inner diameter that is smaller than an outer diameter of the detent, whereby the removal aperture facilitates preventing the detent from escaping the channel until the tool is inserted through the removal aperture. ### Claim 13 (depends on 12) The pin of claim 12, wherein the inner diameter of the installation aperture is greater than the inner diameter of the removal aperture. ### Claim 14 (depends on 12) The pin of claim 12, wherein the inner diameter of the installation aperture is substantially the same as the inner diameter of the removal aperture. ### Claim 15 (depends on 12) The pin of claim 12, wherein the shaft defines a main floor of the channel and a ramp coupled to the main floor of the channel and to the removal aperture, the main floor of the channel extending from the proximate end portion of the channel to the distal end portion of the channel, whereby the ramp facilitates transitioning the pin relative to the detent from the unlocked configuration to the locked configuration with reduced force applied to the pin. ### Claim 16 (depends on 1) A method of installing a pivot pin in a lower receiver of a firearm, the method comprising: providing the pivot pin of claim 1; holding the pivot pin against a front end portion of the lower receiver, the front end portion of the lower receiver defining a detent recess and a pin aperture; while the pivot pin covers the detent recess in the lower receiver, urging a detent into the detent recess in the lower receiver by inserting a tool through the installation aperture in the shaft of the pivot pin; and after the detent is urged into the detent recess in the lower receiver, sliding the pivot pin in the pin aperture, whereby urging the detent into the detent recess in the lower receiver with the tool inserted through the installation aperture in the shaft of the pivot pin facilitates reducing a likelihood that the detent escapes from the detent recess in the lower receiver while holding the pivot pin against the front end portion of the lower receiver. ### Claim 17 (depends on 16) The method of claim 16, further comprising, while the pivot pin covers the detent recess in the lower receiver, inserting the detent through the installation aperture in the shaft of the pivot pin toward the detent recess in the lower receiver, whereby the pivot pin is installed in the lower receiver without using the pivot pin to overcome a bias of a spring in the detent recess in the lower receiver. ### Claim 18 (depends on 16) The method of claim 16, further comprising: temporarily retaining the detent in a retention portion of the installation aperture while the pivot pin covers the detent recess in the lower receiver; while the pivot pin covers the detent recess in the lower receiver, urging the detent out of the retention portion of the installation aperture into the detent recess in the lower receiver by inserting the tool through the installation aperture in the shaft of the pivot pin, the installation aperture having an inner diameter that is smaller than an outer diameter of the detent, the retention portion of the installation aperture having a diameter that is at least as great as the outer diameter of the detent, whereby the installation aperture in the shaft of the pivot pin facilitates increased control over the detent during installation of the pivot pin. ### Claim 19 A pivot pin for a coupling an upper receiver of a firearm to a lower receiver of the firearm, the pivot pin comprising: a head; and a shaft that extends from the head, the shaft defining a detent-retention channel that extends along the shaft, the shaft defining an installation aperture opposite the channel from the head, the channel being configured to receive a detent and to enable the pivot pin to slide relative to the detent in the channel between a locked configuration and an unlocked configuration, the installation aperture being configured to receive a tool that extends through the shaft and to enable the detent to be urged by the tool into a detent recess in the lower receiver while the shaft covers the detent recess in the lower receiver and while the tool extends through the shaft, wherein the installation aperture has an inner diameter that is smaller than an outer diameter of the detent, whereby the installation aperture in the shaft facilitates reducing a likelihood that the detent escapes from the detent recess in the lower receiver during installation of the pivot pin in the lower receiver.