# US 11,306,680 B2 · Exhaust nozzle > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,306,680 B2 - Document ID: US11306680B2 - Status: Granted - Kind: B2 - Application number: 17/072,492 - Filed: 2020-10-16 - Published: 2021-07-22 - Granted: 2022-04-19 - Earliest claimed: 2019-10-31 - Assignees: ROLLS-ROYCE plc - Applicants: ROLLS-ROYCE plc - Inventors: Jack F. Colebrooke - Web page: https://patentgrep.com/patent/US11306680B2 ## CPC - F02K 1/08: by axially moving or transversely deforming an internal member, e.g. the exhaust cone - F02K 1/1207: {of one series of flaps hinged at their upstream ends on a fixed structure (F02K1/1215 - F02K1/1292 take precedence)} - F02K 1/12: by means of pivoted flaps - F02K 1/1223: {of two series of flaps, the upstream series having its flaps hinged at their upstream ends on a fixed structure and the downstream series having its flaps hinged at their upstream ends on the downstream ends of the flaps of the upstream series} - F02K 1/15: Control or regulation - F05D 2220/32: in gas turbines - F05D 2260/56: using cams or eccentrics - F02K: JET-PROPULSION PLANTS (features of jet-propulsion plants common to gas-turbine plants, air intakes or fuel supply control of air-breathing jet-propulsion plants F02C7/00, F02C9/00) - F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS ## Abstract There is disclosed an exhaust nozzle for a gas turbine engine. The exhaust nozzle comprises a frame extending along a longitudinal axis, and a convergent petal pivotably attached at a convergent pivot point to the frame and extending axially downstream and radially inward from the frame. The exhaust nozzle comprises a follower roller fixed to the convergent petal on a radially outer side of the convergent petal, and a cam defining a working surface configured to engage the follower roller to react a force from the convergent petal. The cam is movable along a travel in an axial direction to actuate radial movement of the follower roller to pivot the convergent petal. The cam defines a convex working surface such that a contact angle between the follower roller and the cam varies along the travel to thereby vary an axial component of the force reacted by the cam. ## Claims ### Claim 1 An exhaust nozzle for a gas turbine engine, the exhaust nozzle comprising a frame extending along a longitudinal axis and the exhaust nozzle comprising: a convergent petal pivotably attached at a convergent pivot point to the frame and extending axially downstream and radially inward from the frame; a follower roller fixed to the convergent petal on a radially outer side of the convergent petal; and a cam defining a working surface configured to engage the follower roller to react a force from the convergent petal; wherein the cam is movable along a travel in an axial direction to actuate radial movement of the follower roller to pivot the convergent petal, wherein the cam defines a convex working surface in which a radius of curvature of the cam is located radially outward of the cam, with respect to the longitudinal axis such that a contact angle between the follower roller and the cam varies along the travel to thereby vary an axial component of the force reacted by the cam. ### Claim 2 (depends on 1) The exhaust nozzle according to claim 1, further comprising a divergent petal pivotably attached at a divergent pivot point to a downstream end of the convergent petal, the divergent petal extending axially downstream and radially outward from the divergent pivot point. ### Claim 3 (depends on 2) The exhaust nozzle according to claim 2, wherein the divergent petal is connected to the frame by a linkage such that the frame, convergent petal, divergent petal and linkage form a four-bar linkage. ### Claim 4 (depends on 3) The exhaust nozzle according to claim 3, wherein the linkage is a thrust linkage which is actuatable to change length. ### Claim 5 (depends on 2) The exhaust nozzle according to claim 2, wherein the convergent petal defines a chord length from the convergent pivot point to the divergent pivot point, and wherein the follower roller is fixed between 40-80% along the chord length of the convergent petal from the convergent pivot point. ### Claim 6 (depends on 1) The exhaust nozzle according to claim 1, wherein the cam is moveable between a contracted position in which the cam is in a furthest upstream position and an expanded position in which the cam is in a furthest downstream position, and wherein the cam is configured so that a contact angle between the cam and the follower roller in the contracted position is between 80-100 degrees from the longitudinal axis. ### Claim 7 (depends on 1) The exhaust nozzle according to claim 1, wherein a ratio of a radius of the follower roller to an average radius of curvature of the cam is 0.05 or above. ### Claim 8 (depends on 1) The exhaust nozzle according to claim 1, wherein a ratio of a radius of the follower roller to a maximum radius of curvature of the cam is 0.2 or below. ### Claim 9 (depends on 1) The exhaust nozzle according to claim 1, further comprising a plurality of convergent petals angularly distributed around the exhaust nozzle, each comprising respective rollers, and the exhaust nozzle comprising a corresponding plurality of cams circumferentially spaced around the exhaust nozzle and configured to maintain engagement with a respective roller. ### Claim 10 (depends on 9) The exhaust nozzle according to claim 9, wherein the cam is fixed to a unison ring, and wherein the axial movement of the cam is actuated by axial movement of the unison ring. ### Claim 11 (depends on 10) The exhaust nozzle according to claim 10, wherein there are a plurality of divergent petals corresponding to the plurality of convergent petals. ### Claim 12 (depends on 1) A gas turbine engine comprising an exhaust nozzle according to claim 1. ### Claim 13 An exhaust nozzle for a gas turbine engine, the exhaust nozzle comprising a frame extending along a longitudinal axis and the exhaust nozzle comprising: a convergent petal pivotably attached at a convergent pivot point to the frame and extending axially downstream and radially inward from the frame; a follower roller fixed to the convergent petal on a radially outer side of the convergent petal; and a cam defining a working surface configured to engage the follower roller to react a force from the convergent petal; wherein the cam is movable along a travel in an axial direction to actuate radial movement of the follower roller to pivot the convergent petal, wherein the cam defines a convex working surface such that a contact angle between the follower roller and the cam varies along the travel to thereby vary an axial component of the force reacted by the cam, and wherein a ratio of a radius of the follower roller to an average radius of curvature of the cam is 0.05 or above. ### Claim 14 An exhaust nozzle for a gas turbine engine, the exhaust nozzle comprising a frame extending along a longitudinal axis and the exhaust nozzle comprising: a convergent petal pivotably attached at a convergent pivot point to the frame and extending axially downstream and radially inward from the frame; a follower roller fixed to the convergent petal on a radially outer side of the convergent petal; and a cam defining a working surface configured to engage the follower roller to react a force from the convergent petal; wherein the cam is movable along a travel in an axial direction to actuate radial movement of the follower roller to pivot the convergent petal, wherein the cam defines a convex working surface such that a contact angle between the follower roller and the cam varies along the travel to thereby vary an axial component of the force reacted by the cam, and wherein a ratio of a radius of the follower roller to a maximum radius of curvature of the cam is 0.2 or below.