# US 2013/0240671 A1 · Attachment of Aircraft Ribs to Spars Having Variable Geometry > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0240671 A1 - Document ID: US20130240671A1 - Status: Published application - Kind: A1 - Application number: 13/419,791 - Filed: 2012-03-14 - Published: 2013-09-19 - Earliest claimed: 2012-03-14 - Assignees: The Boeing Company - Inventors: John Scott Kruse; John Hershey Fogarty - Web page: https://patentgrep.com/patent/US20130240671A1 ## CPC - B64C 3/185: {Spars} - B64C 3/187: {Ribs} - B64C 3/34: Tanks constructed integrally with wings, e.g. for fuel or water - B64D 27/353: using solar cells - Y02T 50/50: On board measures aiming to increase energy efficiency - Y10T 29/49826: Assembling or joining - Y10T 403/32861: T-pivot, e.g., wrist pin, etc. - B64C: AEROPLANES; HELICOPTERS - B64D: EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract An aircraft wing includes a rib attached by a joint to a tubular spar that varies in cross sectional shape during flight. The joint includes a ring attached to the tubular spar, and pivot pins connecting the ring with the rib. The pivot pins allow relative movement between the rib and the tubular spar as the tubular spar varies in cross sectional shape. ## Claims ### Claim 1 For use in an aircraft wing, a joint for attaching a rib to a tubular spar that varies in cross sectional shape during flight, comprising: a ring substantially surrounding and attached to tubular spar; and pivot pins connecting the ring with the rib and allowing relative movement between the rib and the tubular spar as the tubular spar varies in cross sectional shape. ### Claim 2 (depends on 1) The joint of claim 1, wherein the ring is compliant and is radially loaded against the tubular spar. ### Claim 3 (depends on 1) The joint of claim 1, wherein the ring has a radial stiffness that is less than a radial stiffness of the tubular spar. ### Claim 4 (depends on 1) The joint of claim 1, wherein: the rib includes a forward portion and a rear portion, and the pivot pins include a first pair of pivot pins pivotally connecting the ring with the forward portion of the rib, and a second pair of pivot pins pivotally connecting the ring with the rear portion of the rib. ### Claim 5 (depends on 1) The joint of claim 1, wherein the ring includes: first and second halves, and splice joints joining the first and second halves together. ### Claim 6 (depends on 1) The joint of claim 1, wherein: the ring extends around and engages substantially the entire circumference of the tubular spar, and the rib includes upper and lower gaps into which the ring and the tubular spar may deform. ### Claim 7 (depends on 1) The joint of claim 1, wherein: the tubular spar varies in cross sectional shape about points of inflection along a curvature of the tubular spar where the curvature changes, and the pivot pins are respectively located substantially at the points of inflection. ### Claim 8 (depends on 1) The joint of claim 1, wherein the ring includes: first portions having a substantially U-shaped cross section, and second portions having a substantially flat cross sectional shape. ### Claim 9 (depends on 1) The joint of claim 1, wherein the ring is formed of a fiber reinforced polymer laminate. ### Claim 10 A joint between a substantially non-deformable structure and a tubular member having a cross sectional shape that deforms about points of inflection along a curvature of the tubular member, comprising: a ring extending substantially around the circumference of and attached to the tubular member; and pivot pins connecting the ring with the non-deformable structure respectively at the points of inflection. ### Claim 11 (depends on 10) The joint of claim 10, wherein: the ring is compliant and is radially loaded against the tubular member substantially around the entire circumference of the tubular member, and the ring is configured to remain compliant to the tubular member as the tubular member deforms. ### Claim 12 (depends on 10) The joint of claim 10, wherein the ring includes: a first portion having a substantially U-shaped cross section, and a second portion includes a substantially flat strap. ### Claim 13 (depends on 10) The joint of claim 10, further comprising: webs on the rib, and wherein the pivot pins are respectively attached to the webs. ### Claim 14 (depends on 10) The joint of claim 10, wherein the ring is formed from a fiber reinforced polymer laminate. ### Claim 15 (depends on 10) The joint of claim 10, wherein: the ring is in tension and is loaded against the tubular member by the tension, and the ring is sufficiently compliant to change shape as the cross sectional shape of the tubular member deforms. ### Claim 16 A method of attaching an aircraft wing rib to a tubular wing spar having a cross sectional shape that may deform during flight, comprising: placing a ring around the tubular spar; loading the ring against the tubular spar; and pivotally connecting the ring to the rib. ### Claim 17 (depends on 16) The method of claim 16, wherein loading of the ring against the tubular spar includes tensioning the ring. ### Claim 18 (depends on 16) The method of claim 16, wherein pivotally connecting the ring to the rib includes locating pivotal connections between the rib and the tubular spar at points of inflection along a curvature of the tubular spar. ### Claim 19 (depends on 16) The method of claim 16, wherein placing the ring around the tubular spar includes: placing two ring halves around the tubular spar, and splicing the ring halves together. ### Claim 20 (depends on 16) The method of claim 16, further comprising: placing webs on the rib, and wherein pivotally connecting the ring to the rib is performed by pivotally connecting the ring to each of the webs. ### Claim 21 A method of transferring loads between a substantially non-deformable structure and a tubular member having a cross sectional shape that deforms under load, comprising: pivoting the tubular member relative to the non-deformable structure as the cross sectional shape of the tubular member deforms. ### Claim 22 (depends on 21) The method of claim 21, wherein pivoting the tubular member relative to the non-deformable structure is performed by pivoting the tubular member about points of inflection when a curvature of the tubular member changes due to the deformation of the tubular member. ### Claim 23 (depends on 21) The method of claim 21, further comprising: transferring loads between the tubular member and the non-deformable structure through a ring surrounding and attached to the tubular member.