Abstract:
An aircraft comprising a first door and a second door, each being mobile between an open position and a closed position, and a maneuvering system. The maneuvering system includes an actuation mechanism, a first transmission chain configured to transmit the movements of the actuation mechanism to the first door, a second transmission chain configured to transmit the movements of the actuation mechanism to the second door. Such a maneuvering system uses a single actuation mechanism, which results in a simplification of the mechanism and a weight saving.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of the French patent application No. 1453877 filed on Apr. 29, 2015, the entire disclosures of which are incorporated herein by way of reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    The present invention relates to an aircraft comprising two landing gear doors and a maneuvering system intended to maneuver said doors. 
         [0003]    An aircraft conventionally comprises two main landing gears. Each main landing gear comprises a leg and a set of tires fixed to the leg. Each main landing gear is retracted into a gear cell behind a door. 
         [0004]    During a landing, each door is opened to allow the associated main landing gear to pass and then is closed again leaving the main landing gear outside. 
         [0005]    Each door is mounted rotationally mobile on the structure of the aircraft and is displaced by an actuation mechanism, such as a cylinder. The aircraft thus comprises two cylinders which must be controlled independently, which is relatively heavy in terms of weight and control management. 
       SUMMARY OF THE INVENTION 
       [0006]    One object of the present invention is to propose an aircraft comprising two doors and a maneuvering system which does not exhibit the drawbacks of the prior art. 
         [0007]    To this end, an aircraft is proposed comprising:
       a first door and a second door, each being mobile between an open position and a closed position, and   a maneuvering system comprising:
           an actuation mechanism,   a first transmission chain intended to transmit the movements of the actuation mechanism to the first door,   
           a second transmission chain intended to transmit the movements of the actuation mechanism to the second door.       
 
         [0013]    Such an aircraft is thus equipped with a single actuation mechanism which simplifies and lightens the mechanism relative to the prior art. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    The features of the invention mentioned above, and others, will become more clearly apparent on reading the following description of an exemplary embodiment, said description being made in relation to the attached drawings, among which: 
           [0015]      FIG. 1  shows an aircraft according to the invention with two doors, 
           [0016]      FIG. 2  shows a cross section of the aircraft along a plane at right angles to the longitudinal axis of the aircraft, when the two doors are closed, 
           [0017]      FIG. 3  is a view similar to that of  FIG. 2  when the two doors are open, 
           [0018]      FIG. 4  and  FIG. 5  are views similar to that of  FIG. 2  when one door is open and the other closed, and 
           [0019]      FIG. 6  is a particular embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0020]      FIG. 1  shows an aircraft  10  seen from below which comprises at least two landing gears. Each landing gear is retracted into a gear cell which is closed by a door  12   a - b.    
         [0021]      FIG. 2  shows the two doors  12   a  and  12   b  in the closed position. The first door  12   a  is here the left door and the second door  12   b  is the right door in the direction of advance of the aircraft  10 . 
         [0022]    Each door  12   a - b  is mounted rotationally mobile on a structure  14  of the aircraft  10  between an open position and a closed position. To this end, the structure  14  has hinges  16   a - b  on each of which is mounted a door  12   a - b.  Each hinge  16   a - b  has an axis which is substantially parallel to the longitudinal axis of the aircraft  10 . 
         [0023]      FIG. 2  also shows a maneuvering system  200  which is fixed to the structure  14  of the aircraft  10  and which comprises a single actuation mechanism  202  such as a cylinder, for example. The actuation mechanism  202  has a position of closure corresponding to a closed position of the doors  12   a - b  and a position of opening corresponding to an open position of the doors  12   a - b.    
         [0024]    The maneuvering system  200  also comprises a first transmission chain  204   a  and a second transmission chain  204   b.    
         [0025]    The first transmission chain  204   a  is intended to transmit the movements of the actuation mechanism  202  to the first door  12   a  and the second transmission chain  204   b  is intended to transmit the movements of the actuation mechanism  202  to the second door  12   b.    
         [0026]    Such an assembly is advantageous because there is only one actuation mechanism  202 , which simplifies the management of the maneuvering system, and lightens the aircraft. 
         [0027]      FIG. 3  shows the two doors  12   a  and  12   b  in the open position and the actuation mechanism  202  in its position of opening. 
         [0028]    For maintenance reasons, it is desirable for each door  12   a - b  to be able to be placed in a closed position while the other door  12   b - a  is in the open position. 
         [0029]      FIG. 4  shows the maneuvering system  200  in which the first door  12   a  is in the open position and in which the second door  12   b  is in the closed position. Thus, a technician can climb along the first door  12   a  using at least one tread incorporated in the structure of the first door  12   a  and move around on the second door  12   b  in order to inspect the corresponding gear cell. 
         [0030]    To this end, the maneuvering system  200  comprises a first clutch means  206   a  designed to alternately assume a coupling position in which the first transmission chain  204   a  transmits the movements of the actuation mechanism  202  to the first door  12   a  and a uncoupling position in which the first transmission chain  204   a  does not transmit the movements of the actuation mechanism  202  to the first door  12   a.    
         [0031]      FIG. 5  shows the maneuvering system  200  in which the first door  12   a  is in the closed position and in which the second door  12   b  is in the open position. Thus, a technician can climb along the second door  12   b  using at least one tread incorporated in the structure of the second door  12   b  and move around on the first door  12   a  in order to inspect the corresponding gear cell. 
         [0032]    To this end, the maneuvering system  200  comprises a second clutch means  206   b  designed to alternately assume a coupling position in which the second transmission chain  204   b  transmits the movements of the actuation mechanism  202  to the second door  12   b  and a uncoupling position in which the second transmission chain  204   b  does not transmit the movements of the actuation mechanism  202  to the second door  12   b.    
         [0033]    Thus, according to the position of each clutch means  206   a - b,  it is possible to independently maneuver each door  12   a - b.    
         [0034]    A particular embodiment of the maneuvering system  200  will now be described. 
         [0035]    The actuation mechanism  202  comprises a cylinder mounted rotationally mobile about a first axis  252  on the structure  14 . The cylinder  202  has a rod  208 , the axis of which is at a right angle to the first axis  252 . The first axis  252  is, here, parallel to the longitudinal axis of the aircraft  10 . 
         [0036]    The maneuvering system  200  comprises a synchronization mechanism  210  intended to synchronize the first transmission chain  204   a  and the second transmission chain  204   b.    
         [0037]    The maneuvering system  200  comprises a coupling mechanism  210  making it possible to mechanically link the first transmission chain  204   a  to the second transmission chain  204   b.    
         [0038]    The two transmission chains  204   a - b  have a common transmission element  210  intended to transmit to each transmission chain  204   a - b  the movements of the actuation mechanism  202  to the associated door  12   a - b.    
         [0039]    In the embodiment of the invention presented here, the synchronization mechanism  210  and the coupling mechanism  210  are one and the same element which is, here, the common transmission element  210 . 
         [0040]    The common transmission element  210  here takes the form of a common vane  210  which takes the form of a part with three articulation points and which is here of triangular form, and which is mounted rotationally mobile about a third axis  256  on the structure  14 , the end of the rod  208  being mounted rotationally mobile about a second axis  254  on the vane  210 . 
         [0041]    The first transmission chain  204   a  also comprises a first arm  212  and a second arm  214 . 
         [0042]    The first arm  212  has a first end mounted rotationally mobile about the third axis  256  and a second end. 
         [0043]    The second arm  214  has a first end mounted rotationally mobile about a fourth axis  258  on the second end of the first arm  212  and a second end mounted rotationally mobile about a fifth axis  260  on the first door  12   a.    
         [0044]    The second axis  254 , the third axis  256 , the fourth axis  258  and the fifth axis  260  are parallel to the first axis  252 . 
         [0045]    Each clutch means  206   a - b  is arranged either between the vane  210  and one of the arms (here, the first arm  212 ), or between two arms (here, the second arm  220  and the third arm  222 ). 
         [0046]    The first clutch means  206   a  takes the form of a securing mechanism which secures the second end of the first arm  212  and the vane  210 . The securing mechanism  206   a  here takes the form of a shaft which is housed in both a hole  216   a  of the vane  210  and a hole  216   b  of the second end of the first arm  212  which are designed for this purpose. 
         [0047]    When the first clutch means  206   a  is in the coupling position, that is to say, when the shaft is in the holes  216   a - b,  and when the first door  12   a  is in the closed position ( FIG. 2 ), the displacement of the rod  208 , here the extension leads to the rocking of the vane  210  and of the first arm  212  about the third axis  256  and therefore the displacement of the second arm  214  and the opening of the first door  12   a  ( FIG. 3 ). 
         [0048]    Conversely, when the first door  12   a  is in the open position ( FIG. 3 ), the displacement of the rod  208 , here the retraction, leads to the rocking of the vane  210  and of the first arm  212  about the third axis  256  and therefore the displacement of the second arm  214  and the closure of the first door  12   a  ( FIG. 2 ). 
         [0049]    When the first door  12   a  is in the open position ( FIG. 4 ) and the first clutch means  206   a  is in the uncoupling position, that is to say, when the shaft is not in the holes  216   a - b,  the displacement of the rod  208  leads to the rocking of the vane  210  about the third axis  256  but not that of the first arm  212 , or that of the second arm  214 , or that of the first door  12   a.  In this case, when the second clutch means  206   b  is in the coupling position, the second door  12   b  can be opened or closed independently of the first door  12   a.    
         [0050]    Conversely, when the first door  12   a  is in the open position ( FIG. 4 ), the displacement of the rod  208 , here the retraction, leads to the rocking of the vane  210  about the third axis  256  but not that of the first arm  212 , or that of the second arm  214 , or that of the first door  12   a.    
         [0051]    The second transmission chain  204   b  also comprises a first arm  218 , a second arm  220 , a third arm  222  and a fourth arm  224 . 
         [0052]    The first arm  218  has a first end mounted rotationally mobile about a sixth axis  262  on the vane  210  and a second end. 
         [0053]    The second arm  220  is mounted rotationally mobile about a seventh axis  264  on the structure  14  and it has a first end mounted rotationally mobile about an eighth axis  266  on the second end of the first arm  218  and a second end. 
         [0054]    The third arm  222  has a first end mounted rotationally mobile about the seventh axis  264  and a second end. 
         [0055]    The fourth arm  224  has a first end mounted rotationally mobile about a ninth axis  268  on the second end of the third arm  222  and a second end mounted rotationally mobile about a tenth axis  270  on the second door  12   b.    
         [0056]    The sixth axis  262 , the seventh axis  264 , the eighth axis  268  and the tenth axis  270  are parallel to the first axis  252 . 
         [0057]    The second clutch means  206   b  takes the form of a securing mechanism which secures the second end of the second arm  220  and the third arm  222 . The securing mechanism  206   b  here takes the form of a shaft which is housed in both a hole  226   a  of the second end of the second arm  220  and a hole  226   b  of the third arm  222  which are provided for this purpose. 
         [0058]    When the second clutch means  206   b  is in the coupling position, that is to say when the shaft is in the holes  226   a - b,  and when the second door  12   b  is in the closed position ( FIG. 2 ), the displacement of the rod  208 , here the extension, leads to the rocking of the vane  210  and of the different arms  218 ,  220 ,  222  and  224  and therefore the opening of the second door  12   b  ( FIG. 3 ). 
         [0059]    Conversely, when the second door  12   b  is in the open position ( FIG. 3  or  5 ), the displacement of the rod  208 , here the retraction, leads to the rocking of the vane  210  and of the different arms  218 ,  220 ,  222  and  224  and therefore the closure of the second door  12   b  ( FIG. 2 ). 
         [0060]    When the second door  12   b  is positioned in the open position ( FIG. 5 ) and the second clutch means  206   b  is in the uncoupling position, that is to say, when the shaft is not in the holes  226   a - b,  the displacement of the rod  208  leads to the rocking of the vane  210 , of the first arm  218  and of the second arm  220 , but not that of the fourth arm  222  or that of the fifth arm  224 . In this case, when the first clutch means  206   a  is in the coupling position, the first door  12   a  can be opened or closed independently of the second door  12   b.    
         [0061]    Conversely, when the second door  12   b  is in the open position ( FIG. 5 ), the displacement of the rod  208 , here the retraction, leads to the rocking of the vane  210 , of the first arm  218  and of the second arm  220 , but not that of the fourth arm  222  or that of the fifth arm  224 , or that of the second door  12   b.    
         [0062]    To ensure the positioning of the doors  12   a - b  in the open position, the structure  14  has, for each transmission chain  204   a - b,  an abutment  228   a - b  against which an element of said transmission chain  204   a - b  comes to bear when the door  12   a - b  concerned is set to the open position by the actuation mechanism  202 . 
         [0063]    In the embodiment of the invention presented here, the abutment  228   a  is an element of the structure  14  against which the first arm  212  of the first transmission chain  204   a  comes to bear. 
         [0064]    In the embodiment of the invention presented here, the abutment  228   a  is an element of the structure  14  against which the second arm  220  of the second transmission chain  204   b  comes to bear. 
         [0065]    The operation of the two doors  12   a - b  is as follows from the closed position of the two doors  12   a - b  ( FIG. 2 ):
       the actuation mechanism  202  is actuated to open the two doors  12   a - b  ( FIG. 3 ),       
 
         [0067]    to ensure maintenance on the first door  12   a,  
       the second clutch means  206   b  is placed in the uncoupling position, in the embodiment described, the shaft is withdrawn from the holes  226   a - b,      the actuation mechanism  202  is actuated to close the doors  12   a - b  but, because of the uncoupling of the second clutch means  206   b,  only the first door  12   a  is closed ( FIG. 5 ), so the technician can perform the maintenance,       
 
         [0070]    to reset the assembly, the actuation mechanism  202  is actuated to close the first door  12   a,  then the second clutch means  206   b  is replaced in the coupling position, 
         [0071]    to ensure maintenance on the second door  12   b,  
       the first clutch means  206   a  is placed in the uncoupling position, in the embodiment described, the shaft is withdrawn from the holes  216   a - b,      the actuation mechanism  202  is actuated to close the doors  12   a - b  but, because of the uncoupling of the first clutch means  206   a,  only the second door  12   b  is closed ( FIG. 4 ), so the technician can then perform the maintenance,       
 
         [0074]    to reset the assembly, the actuation mechanism  202  is actuated to close the second door  12   b,  then the first clutch means  206   a  is replaced in the coupling position. 
         [0075]    To ensure the closure of the doors  12   a - b,  each has a fixing system which fixes said door  12   a - b  to the structure. Each fixing system is removable to allow the door  12   a - b  concerned to open. 
         [0076]    To ensure that the door which is in the closed position during the maintenance does not open accidentally, the technician locks out the fixing system of the closed door  12   a - b  before climbing on top. 
         [0077]      FIG. 6  shows a detail of a particular embodiment of the first transmission chain  204   a,  but this embodiment applies equally to the second transmission chain  204   b.    
         [0078]    The first transmission chain  204   a  comprises a force limiting element  602 . 
         [0079]    Thus, when a door, for example the first door  12   a,  is installed, for example during assembly or adjustment operations, all the force deployed by the actuation mechanism  202  can be made to pass along a single transmission chain  204   a - b  and therefore deform parts if the latter are not sufficiently dimensioned for such a force. Overall, the parts will have to be dimensioned for a force twice the usual operating force (when the two clutch means  206   a - b  are in the coupling position and therefore the two doors  12   a - b  operate simultaneously). 
         [0080]    Each force limiting element  602  is thus designed to absorb the force when the latter is greater than the usual operating force. 
         [0081]    In the embodiment presented in  FIG. 6 , the second arm  214  is cut into two parts and the force limiting element  602  takes the form of a piston system coaxial with the second arm  214  and the sleeve of which is fixed to one of the parts and therefore the rod secured to the piston  603  is fixed to the other part. The piston system  602  further comprises a spring  604  which stresses the piston  603  in the bottom of the sleeve. The stiffness of the spring  604  is such that the spring  604 , and therefore the piston  603 , begins to be displaced only when the force applied to the piston  603  through the part to which it is fixed is greater than the normal maneuvering force. 
         [0082]    Moreover, the travel D of the piston  603  is greater than the travel d of the actuation mechanism  202  (that is to say of the cylinder  202 ) at the end of kinematics, in such a way that the actuation mechanism  202  (here the cylinder  202 ) arrives in abutment before the force limiting system  602  (that is to say, more specifically here, the piston  603 ) arrives in abutment. 
         [0083]    In the case of the second transmission chain  204   b,  the fourth arm  224  has the same arrangement with the associated force limiting element. 
         [0084]    While at least one exemplary embodiment of the present invention(s) is disclosed herein, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. This disclosure is intended to cover any adaptations or variations of the exemplary embodiment(s). In addition, in this disclosure, the terms “comprise” or “comprising” do not exclude other elements or steps, the terms “a” or “one” do not exclude a plural number, and the term “or” means either or both. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise. This disclosure hereby incorporates by reference the complete disclosure of any patent or application from which it claims benefit or priority.