Abstract:
Systems and methods are provided that lock thrust reversers and also drive fan nozzles of an aircraft. One system includes a coupling configured to selectively engage and disengage. While engaged, the coupling is configured to rotate to drive a Variable Area Fan Nozzle (VAFN), at least a portion of which is on a translating portion of a thrust reverser of an aircraft. Furthermore, while engaged the coupling is configured to prevent displacement of the translating portion.

Description:
FIELD 
       [0001]    The invention relates to the field of aircraft, and in particular, to aircraft engines. 
       BACKGROUND 
       [0002]    Turbofan engines provide thrust in order to power an aircraft during takeoff, flight, and landing. Some turbofan engines utilize Variable-Area Fan Nozzle (VAFN) systems in order to alter how they generate thrust. Specifically, a VAFN dynamically adjusts the shape of the output nozzle for the turbofan engine, resulting in numerous benefits such as increased fuel economy and noise reduction. 
         [0003]    Another system used for turbofan engines is known as a thrust reverser. A thrust reverser redirects the output of the engine towards the fore of the aircraft instead of the aft of the aircraft. Thrust reversers may be used, for example, to reduce the speed of an aircraft after landing. One type of thrust reverser is a translating sleeve fan-air thrust reverser. In these thrust reversers, a translating cowl (“transcowl”) of a nacelle that houses the engine slides aftwards, allowing fan air to be rerouted as it travels through the engine. It is generally not desirable to use thrust reversers during flight. For this reason, thrust reversers are often locked in a closed position while the aircraft is in flight. 
       SUMMARY 
       [0004]    Embodiments described herein utilize a coupling that may selectively engage in order to prevent a translating portion of a thrust reverser from moving. While engaged, the coupling is also capable of rotating to drive a VAFN on the translating portion. While disengaged, the coupling allows the translating portion to move. This means that the coupling can serve as both a drive for the VAFN and a locking mechanism for the thrust reverser. 
         [0005]    One embodiment is a system that includes a first coupling member attached to a first structure proximate to a thrust reverser of an aircraft, and a second coupling member attached to a translating portion of the thrust reverser. The translating portion is configured to move relative to the first portion. The first coupling member and the second coupling member are able to engage to prevent movement of the translating portion, and the second coupling member is able to transmit rotation from the first coupling member to an actuator to drive at least a portion of a Variable Area Fan Nozzle (VAFN) located on the translating portion. 
         [0006]    Another embodiment is a system that includes a coupling that is able to selectively engage and disengage. While engaged, the coupling is configured to rotate to drive a Variable Area Fan Nozzle (VAFN), at least a portion of which is on a translating portion of a thrust reverser of an aircraft. Furthermore, while engaged the coupling is configured to prevent displacement of the translating portion. 
         [0007]    Another embodiment is a method of operating a Variable Area Fan Nozzle (VAFN) located on a transcowl of an aircraft. The method includes closing a transcowl of a thrust reverser of an aircraft, and engaging a coupling to lock the transcowl in a closed position. The transcowl includes a movable petal of a VAFN. The method further includes rotating the coupling to move the movable petal. 
         [0008]    Other illustrative embodiments (e.g., methods and computer-readable media relating to the foregoing embodiments) may be described below. The features, functions, and advantages that have been discussed can be achieved independently in various embodiments or may be combined in yet other embodiments further details of which can be seen with reference to the following description and drawings. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0009]    Some embodiments of the present invention are now described, by way of example only, and with reference to the accompanying drawings. The same reference number represents the same element or the same type of element on all drawings. 
           [0010]      FIG. 1  is a perspective view of an engine nacelle mounted to a wing pylon in one example of the present disclosure. 
           [0011]      FIG. 2  is a cut-away back view of an engine nacelle that includes a disengageable coupling in one example of the present disclosure. 
           [0012]      FIG. 3  is an additional cut-away back view of an engine nacelle that includes a disengageable coupling in one example of the present disclosure. 
           [0013]      FIG. 4  is a cut-away back view of an engine nacelle that includes a disengaged coupling in one example of the present disclosure. 
           [0014]      FIG. 5  is a perspective view of an engine nacelle with a translating sleeve thrust reverser that has been moved to an open position in one example of the present disclosure. 
           [0015]      FIG. 6  is a flowchart illustrating a method  600  for operating a disengageable coupling in one example of the present disclosure. 
           [0016]      FIG. 7  is a cut-away top view of a disengageable coupling in one example of the present disclosure. 
       
    
    
     DESCRIPTION 
       [0017]    The figures and the following description illustrate specific examples of the present disclosure. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described or shown herein, embody the principles of the invention and are included within the scope of the invention. Furthermore, any examples described herein are intended to aid in understanding the principles of the invention, and are to be construed as being without limitation to such specifically recited examples and conditions. As a result, the invention is not limited to the specific embodiments or examples described below, but by the claims and their equivalents. 
         [0018]      FIG. 1  is a perspective view  100  of an engine nacelle  110  mounted to a wing pylon  120  of an aircraft according to one embodiment of the present disclosure. Engine nacelle  110  houses an aircraft engine (e.g., a turbofan engine) used to provide thrust during takeoff, flight, and landing. Engine nacelle  110  includes a fan-air Thrust Reversal Actuation System (TRAS) for a thrust reverser, and a Variable Area Fan Nozzle (VAFN)  114 . VAFN  114  is integrated into the translating sleeve (a.k.a., “transcowl”)  112  of the thrust reverser, and therefore moves when transcowl  112  moves. 
         [0019]    Engine nacelle  110  has been enhanced with a multipurpose disengageable coupling. While engaged, such a disengageable coupling locks transcowl  112  into a closed position, while also being able to transmit mechanical rotation to components of transcowl  112  in order to actuate VAFN  114 . Details of a coupling according to some examples herein are described with regard to  FIGS. 2-5  below. 
         [0020]      FIG. 2  is a cut-away back view of an engine nacelle, simplified for illustrative purposes, that includes a disengageable coupling  200  according to one embodiment of the present disclosure. The coupling actuates a Variable Area Fan Nozzle (VAFN)  114 , and includes a first coupling member  210  as well as a second coupling member  220 . Coupling member  210  is attached to transcowl  112  via bearing  244 , while coupling member  220  is attached to a fixed structure of the aircraft that is proximate to the TRAS. In the example shown in  FIG. 2 , coupling member  220  is attached via bearing  242  to hinge beam  270 , which is itself attached to wing pylon  120 . In further embodiments, coupling member  220  may be attached to any suitable component that is fixed relative to transcowl  112  (e.g., wing pylon  120 , a latch beam, or even the engine itself). 
         [0021]    While the coupling members  210 ,  220  are engaged in a cooperating fit with each other, they serve to actuate VAFN  114 , as well as to lock transcowl  112  closed. Similarly, while the coupling members  210 ,  220  are disengaged, the TRAS may freely open and close transcowl  112  in order to reverse thrust as desired. In this embodiment, when transcowl  112  is closed, the shafts  216  and  226  of coupling members  210  and  220  respectively share an axis of rotation and may be extended, retracted and/or vertically translated with respect to the axis of rotation in order to form the cooperating fit. 
         [0022]    In this illustrative example shown in  FIG. 2 , when transcowl  112  is open (as shown in  FIG. 5 ), coupling member  210  has been moved aftward, meaning that coupling members  210  and  220  are no longer aligned for coupling by extension/retraction because the axis of rotation of coupling member  210  is aftward of the axis of rotation of coupling member  220 . In short, coupling member  210  is moved out of the page of  FIG. 4  when transcowl  112  is opened, meaning that coupling member  210  is aftward of its original position while coupling member  220  has remained in place. 
         [0023]    Coupling members  210  and  220  comprise any suitable arrangement of mechanical components (e.g., gears and shafts) for transferring power from a fixed portion of the aircraft to VAFN  114 . Drive system  230  applies torque to shaft  226 , which is mechanically interlocked via interlock gear  222  with coupling member  210 . Interlock gear  212  of coupling member  210  transfers this torque to shaft  216 , causing coupling member  210  to rotate. In this embodiment, coupling member  210  is attached via bearing  244  to a portion of transcowl  112  and may be movable with transcowl  112  relative to fixed structure of the wing (e.g., pylon  120 ). In this regard, the coupling member  210  may also be referred to as the movable coupling member. 
         [0024]    As coupling member  210  rotates, bevel gear  214  drives actuator  250 . Actuator  250  adjusts VAFN  114 , altering the exit nozzle area of the aircraft engine housed within in nacelle  110 . For example, in the embodiment shown in  FIG. 2 , actuator  250  comprises gear  252 , track  254 , rollers  256 , and ramps  258  of a petal-type VAFN. Track  254  forces rollers  256  across ramps  258  to adjust the position of the petals. Other actuation mechanisms for adjusting the area of the VAFN  114  may be used without departing from the scope of the present disclosure. In some examples, the transmission of power to drive actuator  250  may be accomplished without the use of gears  214  and  252  and may instead be implemented according to other conventional techniques. 
         [0025]    While interlock gears  212  and  222  are engaged in a cooperating fit with each other, transcowl  112  is locked/prevented from moving/opening. In some examples, the interlock gears  212  and  222  may be implemented as a Hirth coupling. A Hirth coupling, as may generally be known, may include a pair of shafts coupled together using interlocking teeth which mesh together at the interface between the two shafts. A Hirth coupling may be a suitable implementation as Hirth couplings may generally resist shearing forces that would otherwise act to open transcowl  112  (e.g., shearing forces that would move transcowl  112  out of the page). 
         [0026]    In a further embodiment, the movable coupling member may be housed, at least partially, within a mating structure on transcowl  112 , and this mating structure may bear against the coupling member itself to provide additional resistance to shearing forces. That is, the body of coupling  200  itself (and not just the interlock gears), may serve to resist induced shearing forces that are caused when transcowl  112  attempts to move. An example including features of this kind is further described with regard to  FIG. 7  below. In yet further embodiments, a frictional cooperating fit may be used instead of or in addition to a set of interlocking gears. In examples including a frictional cooperating fit, at least a portion of one of the coupling members may extend into a portion of the other coupling member. 
         [0027]    Drive system  230  may include any system, component, or device capable of applying torque to coupling member  220 . For example, drive system  230  may comprise an electrical motor, hydraulic motor, pneumatic motor, etc. Actuator  250  may include any systems, components, or devices capable of adjusting the orientation of VAFN  114 . For example, actuator  250  may comprise a rotational actuator that adjusts a petal-type VAFN by use of a cable (e.g., as described in U.S. Pre-Grant Patent Publication 2013/0020408), or may use a slider-and-ramp system (e.g., as shown in  FIG. 2 ) to adjust the orientation of VAFN  114 . Further components of engine nacelle  110  and/or wing pylon  120  may be used to internally support coupling members  210  and  220 . For example, each coupling member may be rotatably supported by one or more bearings or brackets (e.g., bearings  244 ,  242 ). 
         [0028]    Nacelle  110  provides a benefit over prior systems because it does not require the use of extensible hydraulic hoses to drive VAFN  114 , which may be particularly subject to wear and fatigue. Additionally, coupling members  210  and  220  can lock the motion of transcowl  112  during flight, which eliminates the need for an independent transcowl locking system and therefore further reduces weight. 
         [0029]      FIG. 3  is an additional simplified cut-away back view of an engine nacelle that includes a disengageable coupling in one example. As illustrated in  FIG. 3 , track  254  and rollers  256  are movable along ramps  258  by rotation of the shaft  216 , which in turn is driven by rotation of shaft  226  transmitted through the disengageable coupling. As the position of track  254  is adjusted in the direction indicated by arrow  280 , the motion of rollers  256  along ramps  258  raises the petals of VAFN  114 . Adjusting the position of the petals of VAFN  114  in turn adjusts the exit nozzle area of the turbofan engine, for example, by moving at least an aft portion of petals  114  radially inward and/or outward. In the example in  FIG. 3 , the exit nozzle area is increased in response to movement of actuator  250  in the direction indicated by arrow  280 . 
         [0030]      FIG. 4  is a cut-away back view, simplified for illustrative purposes, depicting coupling  200  in an embodiment of a disengaged state. According to  FIG. 4 , coupling member  220  has been disengaged (e.g., retracted away) from coupling member  210 . Disengagement of coupling members  210 ,  220  enables transcowl  112  to move relative to the fixed structure of the wing, such that the transcowl may be placed into an open position as shown in  FIG. 5 . In the open position internal cascades  510  of the TRAS, which are normally covered by transcowl  112  are visible, as shown in  FIG. 5 , and a path is provided through the cascades  510  for redirecting flow from the engine in to reverse thrust from the engine. 
         [0031]    In some examples, and as illustrated in  FIG. 4  interlock gears  212  and  222  may have rounded tooth edges  410  and  420 . This feature can provide a benefit by facilitating alignment and/or centering of coupling members  210  and  220  upon engagement of the two (e.g., when transcowl  112  is closed and coupling member  220  is extended back towards coupling member  210  for a cooperating fit). 
         [0032]    Illustrative details of the operation of the disengageable coupling of  FIGS. 2-5  will be discussed with regard to  FIG. 6 . Assume, for this embodiment, that an aircraft has just landed, and has used its TRAS during landing. Thus, transcowl  112  is presently open. 
         [0033]      FIG. 6  is a flowchart illustrating a method  600  for operating a disengageable coupling (e.g., coupling  200 ) in one embodiment according to the present disclosure. The steps of method  600  are described with reference to the disengageable coupling of  FIGS. 2-5 , but the method  600  is not limited to the embodiments of coupling  200  depicted herein. The steps of the flowcharts described herein are not all inclusive and may include other steps not shown. The steps described herein may also be performed in an alternative order. 
         [0034]    In step  602 , a control system moves transcowl  112  into a closed position. In step  604 , coupling member  220  is extended toward coupling member  210  to engage interlock gear  222  in a cooperating fit with interlock gear  212  of coupling member  210 . Coupling member  220  may extend interlock gear  222  by use of hydraulic force, an electric motor, or any suitable mechanism. In some examples, the coupling member  210  may be extended towards coupling member  220  to engage the interlock gears  212  and  222 . 
         [0035]    The cooperating fit between the interlock gears locks transcowl  112  closed, preventing it from moving. In some examples, by virtue of coupling member  210  being attached to transcowl  112  (e.g., through one or more bearings  242 ,  244 ), and since the cooperating fit resists shearing movement, any movement of transcowl  112  with respect to the fixed portion of the aircraft is prevented by coupling member  220  (e.g., any shearing movement with respect to the coupling is prevented by the fit). 
         [0036]    In some examples, coupling member  220  may be arranged perpendicular to the sleeve translation direction of transcowl  112  (e.g., the horizontal coupling shown in  FIG. 2  may instead be oriented vertically) in order to inhibit movement of transcowl  112 . Coupling member  220  and more particularly interlocking gear  222  may thus act as a stopper to the transcowl  112  when the coupling members  210 ,  220  are engaged. 
         [0037]    In further examples, a mating structure on transcowl  112  may house the coupling members during their cooperating fit, and this mating structure may direct shearing forces from transcowl  112  to the coupling itself, which resists these forces (as further described with regard to  FIG. 7 ). 
         [0038]    Transcowl  112  may be maintained in a closed position while coupling  200  remains engaged (e.g., during flight). During flight (e.g., while transcowl  112  is locked and coupling  200  remains engaged), it may be desirable to move the petals of the VAFN  114  to adjust the exit nozzle area. Coupling  200  may therefore be used to transmit torque to VAFN  114 . Accordingly, in step  606 , drive system  230  rotates coupling member  220 , which in turn drives actuation of VAFN  114 , moving the petals of VAFN  114 . 
         [0039]    After landing, transcowl  112  may again be safe to operate. As such, method  600  may include an optional step  608  of disengaging the coupling to enable movement of transcowl  112 . 
         [0040]    Method  600  provides a reliable, efficient technique of locking a TRAS, and driving a VAFN using equipment that is light and not subject to the same fatigue problems as, for example, hydraulic hoses. Thus, method  600  provides a substantial benefit over prior systems because it uses an integrated device to perform functions that were assigned to separate components in the past. 
         [0041]    In a further embodiment, an electronic control system automatically instructs coupling member  220  to extend interlock gear  222  in response to input from a sensor, such as input indicating that transcowl  112  has closed. 
       EXAMPLES 
       [0042]    In the following examples, additional processes, systems, and methods are described in the context of a coupling for a nacelle of an aircraft. While this example illustrates a coupling that is hydraulically extended/retracted, any suitable extension/retraction mechanism may be used (e.g., pneumatic extension, extension via an electrical solenoid, etc.). 
         [0043]      FIG. 7  is a cut-away view illustrating a disengageable coupling  700  in one example of the present disclosure. According to  FIG. 7 , coupling  700  includes splined housing  701  attached to a hinge beam of an aircraft, which holds piston return spring  702 . Piston return spring  702  flexibly extends piston  710  to engage in a cooperating fit with shaft  720  (attached to a transcowl). Housing  701  is attached to hydraulic motor  730  via a gear box  740 , which are both attached to the fixed structure of the aircraft and are used to provide rotational motion to piston  710 . 
         [0044]    Housing  711  includes extend port  703  and retract port  704 , which allow hydraulic pressure from a hydraulic source to enter and exit the chamber that holds piston  710  in order to extend/retract piston  710 . Housing  711  further includes bearings  705  (which facilitate the rotation of piston  710 ), hydraulic seals  706 , bearing retainer  707 , and end gland  708 . Housing  711  is fixedly attached to a hinge beam, a latch beam, wing pylon/strut, or other fixed portion of the aircraft. 
         [0045]    Shaft  720  is housed on transcowl  112  by similar structures and features to those that house piston  710 , but these bearing structures do not include motor coupling arrangements. The structures that house shaft  720  are fixedly attached to transcowl  112 . Since the cooperating fit between shaft  720  and piston  710  resists shearing forces, the cooperating fit also locks the transcowl from moving left or right within the page. Note that as shown in  FIG. 7 , while the piston  710  and shaft  720  are engaged, the coupling itself also resists shearing motions from transcowl  112 , because these shearing motions are borne by the surface “A” of piston  710  when the surface “B” of transcowl  112  applies a shearing force to the coupling. Thus the coupling itself and the cooperating fit both help to resist shearing forces from transcowl  112 . 
         [0046]    An electronic control system may manage the operations of the various hydraulics systems, motors, and other components described herein. Any of the various electronic elements shown in the figures or described herein may be implemented as circuitry, software, firmware, or some combination of these. For example, an element may be implemented as dedicated circuitry. Dedicated circuitry elements may be referred to as “processors”, “controllers”, or some similar terminology. When provided by a processor, the functions may be provided by a single dedicated processor, by a single shared processor, or by a plurality of individual processors, some of which may be shared. Moreover, explicit use of the term “processor” or “controller” should not be construed to refer exclusively to hardware capable of executing software, and may implicitly include, without limitation, digital signal processor (DSP) hardware, a network processor, application specific integrated circuit (ASIC) or other circuitry, field programmable gate array (FPGA), read only memory (ROM) for storing software, random access memory (RAM), non-volatile storage, logic, or some other physical hardware component or module. 
         [0047]    Also, an element may be implemented as instructions executable by a processor or a computer to perform the functions of the element. Some examples of instructions are software, program code, and firmware. The instructions are operational when executed by the processor to direct the processor to perform the functions of the element. The instructions may be stored on storage devices that are readable by the processor. Some examples of the storage devices are digital or solid-state memories, magnetic storage media such as a magnetic disks and magnetic tapes, hard drives, or optically readable digital data storage media. 
         [0048]    Although specific embodiments were described herein, the scope of the invention is not limited to those specific embodiments. The scope of the invention is defined by the following claims and any equivalents thereof.