CROSS REFERENCE TO RELATED APPLICATIONS )

[0001] This application relies for priority on U.S. Provisional Patent Application Serial No. 61/839,440, entitled "MECHANISM FOR TRAILING EDGE CONTROL SURFACE," filed 26 June 2013, which is hereby incorporated herein by reference in its entirety.

TECHNICAL FIELD

[0002] The disclosure relates generally to the actuation of aircraft flight control surfaces, and more particularly to mechanisms for guiding the movement of such flight control surfaces.

BACKGROUND OF THE ART

[0003] Many fixed wing aircraft have trailing edge flaps movably mounted to wings and which are deployed with suitable mechanisms. Several types of flap deployment mechanisms exist to achieve the desired movement of the trailing edge flaps. For example, such flap deployment mechanisms may include links, carriages and tracks which may be too bulky to be entirely housed inside the bodies of the wings to which the flaps are mounted. Accordingly, mechanisms for deploying such flaps often extend below a lower skin of the wing and are housed in suitable fairings.

[0004] The primary function of such fairings is to produce a smooth outline and reduce drag that would otherwise be produced by flap deployment mechanisms being exposed to the stream of air around the wing. However, some flap deployment mechanisms are relatively bulky and can require relatively large fairings which can entail significant aerodynamic penalties.

[0005] Improvement is therefore desirable.

SUMMARY

[0006] The disclosure describes components, mechanisms, assemblies and methods useful in the actuation of flight control surfaces of aircraft. In some aspects, the disclosure relates to the actuation of trailing edge control surfaces such as, for example, trailing edge flaps mounted to wings of fixed- wing aircraft. [0007] In one aspect, the disclosure describes a mechanism for guiding the movement of a trailing edge control surface relative to an aircraft wing structure. The mechanism may comprise: a track member configured to be fixed to the trailing edge control surface and to be movably coupled to the wing structure, the track member defining a track; and a first guide member configured to be fixed to the wing structure and to engage the track of the track member for guiding the movement of the track member relative to the wing structure during movement of the trailing edge control surface relative to the wing structure.

[0008] In another aspect, the disclosure describes an assembly that may comprise: an aircraft wing structure; a trailing edge control surface; and a mechanism movably coupling the trailing edge control surface to the aircraft wing structure. The mechanism may comprise: a track member fixed to the trailing edge control surface and movably coupled to the wing structure, the track member defining a track; and a first guide member fixed to the wing structure and engaging the track of the track member for guiding the movement of the track member relative to the wing structure during movement of the trailing edge control surface relative to the wing structure.

[0009] In another aspect, the disclosure describes aircraft that may comprise one or more of the components, mechanisms and assemblies disclosed herein.

[0010] In a further aspect, the disclosure describes a method of moving a trailing edge control surface relative to an aircraft wing structure using a track member fixed to the trailing edge control surface and movably coupled to the aircraft wing structure where a first guide member fixed to the wing structure is engaged with a track of the track member. The method may comprise: actuating the trailing edge control surface to cause movement of the trailing edge control surface and of the track member relative to the aircraft wing structure; and guiding movement of the track member relative to the aircraft wing structure using the first guide member.

[0011] Further details of these and other aspects of the subject matter of this application will be apparent from the detailed description and drawings included below.

DESCRIPTION OF THE DRAWINGS

[0012] Reference is now made to the accompanying drawings, in which: [0013] FIG. 1 shows a top view of a trailing edge control surface movably coupled to an aircraft wing structure;

[0014] FIG. 2 shows a side elevation view of a mechanism in a retracted position for guiding the movement of the trailing edge control surface of FIG. 1 relative to the aircraft wing structure;

[0015] FIG. 3 A shows another side elevation view of the mechanism of FIG. 2 in the retracted position relative to the aircraft wing structure;

[0016] FIG. 3B shows a side elevation view of the mechanism of FIG. 2 in a deployed position relative to the aircraft wing structure;

[0017] FIG. 4 shows a cross-sectional view of a first guide member of the mechanism of FIG. 2 taken along line 4-4 of FIG. 3A;

[0018] FIG. 5 shows a cross-sectional view of a second guide member of the mechanism of FIG. 2 taken along line 5-5 of FIG. 3A;

[0019] FIG. 6A shows a side elevation view of a track member of the mechanism of FIG. 2;

[0020] FIG. 6B shows a cross-sectional view of the track member of FIG. 6A taken along line 6B-6B of FIG. 6A; and

[0021] FIG. 7 shows a side elevation view of another mechanism in a retracted position for guiding the movement of the trailing edge control surface of FIG. 1 relative to the aircraft wing structure.

DETAILED DESCRIPTION

[0022] Aspects of various embodiments of the present disclosure are described through reference to the drawings.

[0023] FIG. 1 illustrates a top view of an assembly, shown generally at 10, that may comprise one or more flight control surfaces 12 movably coupled to an aircraft wing structure 14. Wing structure 14 may be part of a wing of an aircraft (not shown). The aircraft to which assembly 10 may be mounted may include, for example, any suitable aircraft such as corporate, private, commercial or any other type of aircraft. For example, wing structure 14 may be part of a fixed- wing aircraft that is propelled forward by thrust from a jet engine or propeller.

[0024] Flight control surface 12 may include any known or other suitable flight control surface. For example, control surface 12 may comprise a trailing edge control surface that may be disposed at or near a trailing edge of the wing to which control surface 12 may be mounted. In some embodiments, control surface 12 may comprise a trailing edge flap which may be used as a "high-lift" surface that may be deployed to increase the amount of lift generated by the wing to which control surface 12 may be mounted. For example, such trailing edge flap may be deployed during landing, take-off and/or during any other appropriate phases of flight or conditions requiring increased lift. Control surface 12 may, in some embodiments, define at least a portion of a trailing edge of the wing to which control surface 12 may be mounted.

[0025] Depending of the position of control surface 12 along the wing and also its use, control surface 12 may, in some embodiments, be configured for deployment along a trajectory that is partially generally along arrow A (as viewed from the top) shown in FIG. 1. It is understood that the deployment trajectory of control surface 12 may not necessarily be linear and may be selected based on aerodynamic performance considerations. Arrow A may in some embodiments be generally parallel to a longitudinal axis of a fuselage of the aircraft. For example, arrow A may correspond generally to a streamwise direction of the air flowing over the wing of the aircraft. In some embodiments, the deployment direction may be at an angle relative to a sweep angle of the wing. In some embodiments the deployment direction may be generally perpendicular to a trailing edge of a swept wing.

[0026] One or more of such assemblies 10 may be disposed on a wing of an aircraft. For example, a wing could comprise an inboard assembly and an outboard assembly disposed laterally outward from the inboard assembly where the inboard and outboard dispositions may be relative to a fuselage of the aircraft. Control surface 12 may be configured to be translatable and/or rotatable relative to wing structure 14. Even though the exemplary control surface 12 depicted herein is a trailing edge flap, it is understood that components, assemblies, mechanisms, methods and various aspects described herein could be used in conjunction with flight control surfaces other than trailing edge flaps.

[0027] Assembly 10 may comprise one or more actuators 16A, 16B that may serve to actuate control surface 12 relative to wing structure 14 between a retracted position and a deployed position. Actuators 16A and 16B may be laterally spaced apart from each other. For example, first actuator 16A may be disposed closer to a first lateral (e.g., outboard) portion 12A of control surface 12 and second actuator 16B may be disposed closer to a second lateral (e.g., inboard) portion 12B of control surface 12.

[0028] First and second actuators 16A, 16B may be of the same or of different types. For example, first and second actuators 16 A, 16B may each comprise one or more screws 18 A, 18B (e.g., ball-type screws) secured to wing structure 14 and one or more cooperating nuts 20A, 20B secured to control surface 12 and engaged to corresponding screws 18 A, 18B. The rotation of screws 18 A, 18B may cause translation of nuts 20A, 20B along screws 18 A, 18B and

consequently cause movement of control surface 12 at least partially along arrow A. Screws 18A, 18B may be driven and controlled by one or more suitable drivers of known or other types and configured to controllably deploy and retract control surface 12. For example, such driver(s) may be at least partly synchronized to provide relatively coordinated movement of first lateral portion 12A and of second lateral portion 12B of control surface 12.

[0029] Assembly 10 may comprise one or more mechanisms 22A, 22B for guiding the movement of control surface 12 during deployment and/or retraction. It is understood that, in some embodiments, mechanisms 22A, 22B could also be used to actuate control surface 12. For example, in some embodiments, one or more of mechanisms 22A, 22B could be driven by a suitable driver in the same or other manner as described above in relation to actuators 16A, 16B. Accordingly, in some embodiments where mechanisms 22A, 22B may be driven and used to actuate control surface 12, separate actuators 16 A, 16B may not be required.

[0030] Mechanisms 22A, 22B may serve to guide the position and/or orientation of control surface 12 based on desired aerodynamic conditions (e.g., performance) to be produced by control surface 12 at and between the retracted position and the deployed position. Accordingly, mechanisms 22A, 22B may be coupled between control surface 12 and wing structure 14. For example, wing structure 14 may comprise one or more structural ribs 24 to which mechanisms 22A, 22B may be secured. For example, each of mechanisms 22A, 22B may be disposed between and supported by two adjacent ribs 24.

[0031] FIG. 2 shows a side elevation view of one of mechanisms 22A, 22B in a retracted position with one of the ribs 24 removed to permit the illustration of mechanisms 22A, 22B. Since both mechanisms 22A, 22B may generally have the same configuration, mechanisms 22A, 22B will be collectively referred to herein as mechanism 22. However, even though mechanisms 22A, 22B may comprise similar components, they may comprise some differences that permit non-cylindrical (e.g., conical) movement of control surface 12. Conical deployment of a trailing edge flap may be desired in some embodiments depending on the particular application since it may, in some circumstances, provide a more uniform aerodynamic loading (e.g., spanwise and/or chord wise) on the wing to which the trailing edge flap may be mounted. For example, mechanisms 22A, 22B may be configured so that the movement of first lateral portion 12A of control surface 12 is not identical to the movement of second lateral portion 12B of control surface 12. Alternatively, mechanisms 22A, 22B may be configured so that the movement of first lateral portion 12A is substantially identical to the movement of second lateral portion 12B so that the movement of control surface 12 may be substantially cylindrical.

[0032] Mechanism 22 may comprise track member 28 configured to be fixed to control surface 12 and to be movably coupled to one or more of ribs 24. Track member 28 may comprise one or more tracks 30. Mechanism 22 may also comprise one or more first guide members 32 configured to be fixed to rib 24 and to engage track 30 of track member 28 for guiding the movement of the track member 28 relative to rib 24 (i.e., wing structure) during movement of control surface 12 relative to the rib 24. First guide member 32 may comprises one or more rollers rotatably secured to rib 24 and configured to engage track 30 so as to guide the movement of track member 28 as track member 28 is moved relative to rib 24.

[0033] Track member 28 may be fixedly secured to control surface 12 at one or more points or regions. For example, track member 28 may be secured to a forward portion of control surface 12 via flange 34 and one or more suitable fasteners 36. Fastener(s) 36 may include one or more bolts, pins and/or one or more removable or permanent fasteners. Similarly, alternatively or in addition, track member 28 may be secured to an aft portion of control surface 12 via flange 38 and bracket 40. Bracket 40 may be secured to flange 38 by one or more suitable fasteners 42. Bracket 40 may in turn be secured to control surface 12 via fasteners 44. Fasteners 42, 44 may include one or more bolts, pins and/or one or more removable or permanent fasteners.

[0034] A forward portion of track member 28 may be movably coupled to rib 24 via one or more second guide members 45. For example, second guide member 45 may include a swing arm having first end 45A configured for rotatably coupling to rib 24 at first pivot 46 and second end 45B configured for rotatably coupling to track member 28 at second pivot 48. [0035] The combination of track member 28, first guide member 32 (e.g., roller) and second guide member 45 (e.g., swing arm) may be configured to provide the desired movement of control surface 12 between the retracted and deployed position. For example, mechanism 22 may be configured to produce movement of control surface 12 that includes translation and/or rotation relative to rib 24. For example, track member 28 may be guided via first guide member 32 and second guide member 45 so that the movement of track member 28 relative to rib comprises translation and/or rotation. For example, as second guide member 45 is rotated in the direction of arrow R, during deployment of control surface 12, track member 28 may be translated and rotated relative to first guide member 32, which may be fixed to rib 24. Accordingly, track 30 and track member 28 may be translated while being guided by first guide member 32 which may be engaged with track 30. First guide member 32, may also serve as a pivot point for track member 28 (and consequently also for control surface 12) as track member 28 is rotated during deployment and/or retraction. Accordingly, as track member 28 is deployed or retracted relative to first guide member 32, the pivot point of rotation of track member 28 may move along track 30.

[0036] As mentioned above, mechanism 22 may be configured to cause movement of track member 28 and control surface 12 that includes translation, rotation or combinations thereof. For example, mechanism 22 may be configured to cause Fowler- type movement of control surface 12 relative to rib 24 during deployment/retraction of control surface 12. For example, initial deployment may comprise mainly translational movement while subsequent deployment may comprise mainly rotational movement. In some embodiments, the initial 75% of the total deployment of control surface 12 may cause about 50% of the total rotation of control surface 12 and the final 25% of the deployment may cause about 50% of the total rotation of control surface 12. In cases where control surface 12 comprises a trailing edge flap, the total deployment of such trailing edge flap may, for example, comprise up to about 37 degrees of rotation.

[0037] One skilled in the relevant arts will appreciate that the movement of control surface 12 may be defined at least in part by the shape of track(s) 30 of track member 28 and that the shape of track(s) 30 may be designed or selected to achieve a desired movement of track(s) 30 based on specific requirements. Accordingly, it is understood that components, mechanisms, assemblies and methods of the present disclosure may be used in conjunction with tracks having different shapes than those shown herein and also with control surfaces that undergo different types of movements and also different combinations of movements than those shown herein.

[0038] Mechanism 22 may also be configured so that the movement of control surface 12 takes into consideration aerodynamic performance when control surface 12 is moved relative to wing structure 14 (including ribs 24) and/or other aerodynamic surfaces of the aircraft wing. For example, the aircraft wing may comprise one or more other aerodynamic surfaces 50 which may be fixed or movable and that may be disposed near control surface 12. In some embodiments, aerodynamic surface 50 may comprise a spoiler (e.g., air brake) that may, under certain circumstances, be deployed upwardly relative to control surface 12. Accordingly, movement of control surface 12 may be selected so that substantial aerodynamic continuity may be maintained between control surface 12 and other aerodynamic surface(s) 50 during at least a portion of the deployment and/or retraction of control surface 12. In some embodiments, the movement of control surface 12 may be selected so that significant (e.g., aerodynamically penalizing) gaps between control surface 12 and other adjacent structure such as aerodynamic surface 50 may be avoided or at least limited during at least a portion of the deployment and/or retraction of control surface 12.

[0039] FIG. 3A shows a side elevation view of mechanism 22 shown in the retracted position with rib 24 shown in front of mechanism 22. As mentioned above, mechanism 22 may be disposed between and supported by two adjacent ribs 24 which may form part of wing structure 14.

[0040] FIG. 3B shows another side elevation view of mechanism 22 where mechanism 22 and control surface 12 are shown in the deployed position. Rib 24, 14 is shown as being partially transparent to provide a better view of mechanism 22.

[0041] FIG. 4 shows a cross-sectional view of first guide member 32, track member 28 and ribs 24 taken along line 4-4 in FIG. 3A. As shown in FIG. 1, adjacent ribs 24 may be laterally spaced apart so that track member 28 may be disposed between two ribs 24. In some

embodiments, track member 28 may comprise two tracks 30. For example, the two tracks 30 may be laterally opposed so that tracks 30 open to opposite lateral directions. Accordingly, first guide member 32 may comprise two rollers 32A where each one of rollers 32A is engaged to a respective one of tracks 30 formed in track member 28. The two rollers 32A of first guide member 32 may be disposed substantially coaxially along pivot axis P so that both rollers 32A can together form a common and fixed pivot point/axis about which track member 28 may be rotated during retraction/deployment. Tracks 30 and corresponding rollers 32A may be sized to permit rotation of rollers 32A during movement of track member 28. Each of rollers 32A may be rotatably coupled to a respective rib 24 via pins 52.

[0042] Track member 28 may also comprise channel 54. Channel 54 may be disposed between tracks 30 but open towards a vertical (e.g., downward) direction. Channel 54 may be configured to receive lateral guide member 56 that may serve to manage lateral loads between track member 28 and ribs 24. For example, lateral guide member 56 may be engaged with channel 54 so as to further guide the movement of track member 28 and prevent or hinder excessive lateral movement of track member 28 relative to ribs 24 under expected lateral loads. Lateral guide member 56 may in some embodiments be frictionally engaged with channel 54. For example, lateral guide member 56 may include one or more bearing surfaces for engagement with channel 54. Lateral guide member 56 may comprise a suitable bearing material sold under the trade name ΟΠ ΤΕ or other suitable material(s). Lateral guide member 56 may be fixedly secured to one or more of ribs 24 or other part of wing structure 14 via retainer 58 and pin 60 extending through retainer 58.

[0043] As mentioned above, mechanism 22 may be configured to permit non-cylindrical (e.g., conical) movement of movable surface 22 relative to wing structure 14. Accordingly, rollers 32A, tracks 30 and lateral guide member 56 may be configured to accommodate some degree of skewing and/or tilting of movable surface 22 (and consequently track member 28) that may be associated with such non-cylindrical movement. For example tracks 30 may have a depth that is greater than the size of corresponding rollers 32A and channel 54 may have a depth greater than the size lateral guide member 56. Lateral guide member 56 may be disposed relatively close to or be substantially aligned with pivot axis P and have a suitable shape so as to permit some skewing and/or tilting of track member 28 if needed.

[0044] FIG. 5 shows a cross-sectional view of second guide member 45 of mechanism 22 taken along line 5-5 of FIG. 3A. Additionally shown in FIG 5 are upper skin 62 and lower skin 64 of the aircraft wing to which control surface 12 may be mounted and an outline of an exemplary fairing 66 that may be used to cover portions of mechanism 22 and/or other components extending below lower skin 64 of the aircraft wing. Second guide member 45 (e.g., swing link) may have an overall height HI when mechanism 22 is in the retracted position. However, since second guide member 45 may be disposed forward of control surface 12, it may be disposed in a region of the aircraft wing where the height of the wing (i.e., the distance between upper skin 62 and lower skin 64) is greater than the height of a more aft region of the aircraft wing. Accordingly, due at least in part to the position of second guide member 45 being forward of control surface 12, a significant portion of height HI may be disposed between upper skin 62 and lower skin 64. Hence, only a portion of second guide member 45 of height H2 extending below lower skin 64 may require covering/shielding by fairing 66. In some

embodiments, mechanism 22 may require a smaller fairing than some other prior art mechanisms having relatively large portions of their mechanisms extending below the lower skin of their aircraft wing. The reduction in the size of such fairings may in turn result in smaller aerodynamic penalties associated with such fairings.

[0045] First end 45A of second guide member 45 may be rotatably coupled to one or more ribs 24 via first pin 68 and first bearing 70. Second end 45B of second guide member 45 may be rotatably coupled to track member 28 via second pin 72 and second bearing 74. Second bearing 74 may be of self-aligning (e.g., spherical) type and accordingly may accommodate some skewing and/or tilting of track member 28 associated with non-cylindrical (e.g., conical) movement of control surface 12, while still reacting to lateral loads.

[0046] In some embodiments, one or more additional guide members (not shown) may be provided for use in the event of failure for example. The additional guide member(s) may be configured to engage with track 30 in the event of a failure and/or loss of one or more of rollers 32. Such additional guide members may, for example, be configured for temporary use and may comprise one or more protrusions (e.g., bosses) secured to or integrally formed with rib 24, 14 and extending at least partially into track(s) 30.

[0047] FIG. 6A shows a side elevation view of track member 28 of mechanism 22 and FIG. 6B shows a cross-sectional view of track member 28 taken along line 6B-6B of FIG. 6A.

[0048] FIG. 7 shows a side elevation view of mechanism 22 for guiding the movement of control surface 12 according to another exemplary embodiment. FIG. 7 also shows mechanism 22 in the retracted position. The mechanism shown in FIG. 7 shares similarities with the mechanism shown in the previous figures so the detailed description of similar elements will not be repeated in relation to FIG. 7. Also, like reference numerals have been used to identify like elements.

[0049] In reference again to FIG. 7, mechanism 22 may be configured for guiding the movement of control surface 12 relative to ribs 24 having different configurations than those previously shown. For example, ribs 24 may be configured so that first guide member 32 is disposed higher relative to control surface 12 than for the ribs 24 shown in the previous figures. Consequently, track member 28 may also be disposed relatively higher in relation to control surface 12. Accordingly, second guide member 45 may be rotatably coupled to track member 28 via intermediate member 76. Second guide member 45 may be rotatably coupled to intermediate member 76 via a self-aligning bearing (not shown) as discussed above to accommodate non- cylindrical movement of control surface 12. Intermediate member 76 may be fixedly secured to control surface 12 via one or more fasteners 78. Track member 28 and intermediate member 76 may be fixedly secured to each other via overlapping flanges 34 and 80. Accordingly, track member 28 may be fixedly secured to control surface 12 and movably coupled to one or more of ribs 24. Also, first guide member 32 may be configured to be fixed to one or more of ribs 24 and to engage track(s) 30 of track member 28 for guiding the movement of track member 28 during movement of control surface 12 relative to ribs 24 or to other wing structure 14. Again, movement of track member 28 relative to ribs 24 may include translation, rotation or a combination thereof.

[0050] While specific embodiments have been illustrated and described above, it is understood that the specific configuration of mechanisms 22 including relative positioning of elements and dimensional proportions between elements may be varied to accommodate a wide range of conditions and may also be varied based on the movement of control surface 12 that is desired.

[0051] During operation, control surface 12 may be actuated as required using actuators 16A, 16B between the retracted and the deployed positions. In some situations, control surface 12 may be deployed/retracted to intermediate positions between the retracted and the deployed position and maintained at such intermediate position(s) as desired and commanded by either an operator (e.g., pilot) (not shown) of the aircraft or by an auto-flight system (not shown) of the aircraft. In other embodiments where mechanism 22 may itself be actuated, separate actuators 16 A, 16B may not be required. However, in the exemplary embodiment shown, as control surface 12 is deployed or retracted via actuators 16 A, 16B, mechanism 22 may guide the movement of control surface 12 relative to wing structure 14. Since track member 28 may be fixed to control surface 12, such movement may also cause movement of track member 28 relative to wing structure 14.

[0052] The movement of track member 28 (and consequently of control surface 12) may be guided by first guide member 32 and/or second guide member 45. Under such guiding, track member 28 may undergo translation relative to first guide member 32 and also rotation about first guide member 32 (see pivot axis P in FIG. 4) as fist guide member 32 is engaged with track 30 of track member 28. Second guide member 45 may be disposed forward of control surface 12 and be rotatably coupled to a forward portion of track member 28. The initial (i.e., nearly vertical) disposition of second guide member 45 may cause upward movement of the forward portion of track member 28 during at least a portion of deployment of control surface 12.

[0053] In some embodiments, the guiding provided by mechanism 22 may, result in control surface 12 undergoing Fowler-type deployment/retraction. In some embodiments, the movement of control surface 12 may be conical as explained above.

[0054] The above description is meant to be exemplary only, and one skilled in the relevant arts will recognize that changes may be made to the embodiments described without departing from the scope of the invention disclosed. The present disclosure may be embodied in other specific forms without departing from the subject matter of the claims. Also, one skilled in the relevant arts will appreciate that while the mechanisms, assemblies and methods disclosed and shown herein may comprise a specific number of elements/components, the mechanisms, assemblies and methods could be modified to include additional or fewer of such

elements/components. The present disclosure is also intended to cover and embrace all suitable changes in technology. Modifications which fall within the scope of the present invention will be apparent to those skilled in the art, in light of a review of this disclosure, and such modifications are intended to fall within the appended claims.