Abstract:
The invention relates to a securing plate ( 1 ) for removably securing a one-piece propulsion unit ( 17 ) to a wing of an aircraft, characterised in that it includes first connection means ( 4, 5, 8, 13, 14 ) for securing the plate to the wing, second connection means ( 24 ) for securing the one-piece propulsion unit to the plate and third connection means ( 7 ) for securing a pair of longitudinal handling members ( 22 ) to the plate. The invention also relates to a specific longitudinal member and to an installation including a one-piece propulsion unit secured in the plate.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates in particular to a securing plate for removably securing a one-piece propulsion unit to a wing of an aircraft. 
       BACKGROUND 
       [0002]    It has been known for a very long time to design a nacelle for an aircraft adapted to be mounted around an engine including a blower casing, said nacelle comprising a connecting structure adapted to be mounted on the downstream edge of said casing, on the one hand, and on a pylon, on the other hand, this pylon being fastened to a wing or part of the fuselage of the aircraft. 
         [0003]    An engine change is effected by disconnecting the engine at the level of the suspension. Some cowls of the nacelle, known as the Transcowl and the Fan Cowl, remain connected to the pylon and must therefore be held open to enable replacement of the engine. A device for raising and lowering the engine is then used. This device comprises two independent longitudinal members disposed transversely relative to the axis of the engine, one being fixed to the front of the pylon and the other to the middle. A bootstrap type lifting system is provided at each end of the two longitudinal members so as to be able to adjust the height of the engine at four points, each lifting system being independent of the other three. 
         [0004]    However, employing a one-piece propulsion unit instead of a standard assembly as referred to above has recently been envisaged. Accordingly, in such a one-piece propulsion unit, the engine, the nacelle and the pylon are inseparable and the usual interface disappears. 
         [0005]    In such a configuration, the standard engine change maintenance procedure is rendered obsolete since the pylon is now fastened to the engine and the nacelle and thus can no longer support the two longitudinal members described above. 
       BRIEF SUMMARY 
       [0006]    The disclosure provides a securing plate for removably securing a one-piece propulsion unit to a wing of an aircraft, characterized in that it includes first connection means for securing the plate to the wing, second connection means for securing the one-piece propulsion unit to the plate, and third connection means for securing a pair of longitudinal handling members to the plate. 
         [0007]    Accordingly, after securing the longitudinal members and equipping each of them with a standard bootstrap system, it suffices to disconnect the one-piece propulsion unit from the plate attached to the wing to carry out the maintenance operation. This therefore enables the engine change to be carried out in a very short time as well as limiting the number of manual operations. The present invention therefore creates a new interface between the handling tooling on the ground and the parts remaining fixed to the wing. 
         [0008]    In a preferred embodiment of the first connection means the latter means are produced in the form of attachment fixtures. 
         [0009]    At least one first attachment fixture and one second attachment fixture facing each other are preferably provided on either side of the plate. 
         [0010]    At least one front attachment fixture is preferably provided in the front part of the plate and/or at least one rear attachment fixture is provided in the rear part of the plate. 
         [0011]    In a preferred embodiment of the second connection means the latter means are produced in the form of holes formed in the plate. 
         [0012]    In a preferred embodiment of the third connection means the latter means are produced in the form of holes formed in the plate. 
         [0013]    The present invention also relates to a longitudinal handling member intended to be fixed in a securing plate according to the invention, characterized in that it comprises first connection members adapted to cooperate with the first connection means of the plate and second connection members for connection to the wing. 
         [0014]    The first connection members advantageously comprise a first junction fixture in the central part. 
         [0015]    The second connection members advantageously comprise a second junction fixture in the rear part. 
         [0016]    A longitudinal member according to the invention preferably comprises a front part adapted to receive a link disposed transversely and/or this longitudinal member can comprise a central part adapted to receive a link disposed transversely. 
         [0017]    Finally, the invention also relates to a securing plate according to the invention fixed in a wing of an aircraft and a one-piece propulsion unit attached to said plate. 
         [0018]    During maintenance operations this installation advantageously comprises two longitudinal members according to the invention disposed along the axis of the one-piece propulsion unit and connected to the plate. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]    The invention will be better understood with the aid of the detailed description given hereinafter with reference to the appended drawings, in which: 
           [0020]      FIG. 1  is a perspective view of a securing plate of the invention; 
           [0021]      FIG. 2  is a diagrammatic perspective view of an installation of the invention during a maintenance operation; 
           [0022]      FIG. 3  is a view similar to  FIG. 2  with the wing omitted; 
           [0023]      FIG. 4  is a side view of the installation represented in  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION 
       [0024]    A securing plate  1  of the invention, as more specifically represented in  FIG. 1 , comprises a substantially plane base  2  substantially forming an isosceles trapezium and intended to be fixed into a wing  3  of an aircraft. 
         [0025]    This base  2  includes six holes  24  arranged in a V-shape. Also, this base  2  is between a first attachment fixture  4  and a second attachment fixture  5  facing each other and oriented outwardly in a plane perpendicular to said base  2 . A rear orifice  6  and two front holes  7  are provided in each of the two attachment fixtures  4 ,  5 . 
         [0026]    The base  2  also includes a third attachment fixture  13  and a fourth attachment fixture  14  facing each other and oriented outward in a plane perpendicular to said base  2 . These two attachment fixtures  13 ,  14  are each furnished with a hole  15  and are aligned with the first and second attachment fixtures  4 ,  5  so that the orifices  6  and the holes  15  are also aligned. 
         [0027]    A front attachment fixture  8  furnished with an eyelet  9  is provided in the front part of the upper face of the base  2 , on the axis of symmetry of the base  2 , and so is not in alignment with the attachment fixtures  4 ,  5 ,  13  and  14 . 
         [0028]    As more particularly represented in  FIG. 4 , the base  2  is extended at the rear by a rear attachment fixture  10  oriented inwardly in a plane perpendicular to said base  2 . This rear attachment fixture  10  is equipped with an eyelet (not shown) disposed on the axis of symmetry of the base  2 . 
         [0029]    The plate  1  can therefore be fixedly attached to the wing  3  by means of its attachment fixtures  4 ,  5 ,  8 ,  10 ,  13  and  14 . 
         [0030]    To be more precise, each pair of attachment fixtures  4 ,  13  and  5 ,  14  can be bolted into a fixed lug (not shown) of the wing  3  to provide balanced retention. The eyelet  9  of the front attachment fixture  8  and the eyelet of the rear attachment fixture  10  are connected to a fixed point of the wing  3  by a respective link  11 ,  12 . 
         [0031]    To be more precise, the one-piece propulsion unit is broadly divided into an engine (not shown), a nacelle  18  and a pylon  19  that cannot be separated from each other. Broadly speaking, the nacelle  18  comprises a front structure  20  around the casing and a rear structure  21  generally serving as a thrust reverser. 
         [0032]    The one-piece propulsion unit  17  is fixedly attached in the base  2  by bolts in the holes  24 . 
         [0033]    To carry out maintenance operations during which the engine is in particular removed and then reinstalled, it is necessary to use two handling longitudinal members  22  as represented in  FIGS. 1 to 4 . 
         [0034]    Each of these two longitudinal members  22  comprises a front part  23 , a central part  25  that can be inclined and equipped with at least a first junction fixture  26 , and a rear part  27  equipped with a second junction fixture  28 , these first and second junction fixtures  26 ,  28  being disposed outwardly in a plane perpendicular to the base  2 . 
         [0035]    As can be deduced more particularly from  FIG. 1 , the first junction fixture  26  in this example is equipped with two holes  30  similar to the holes  7  of the attachment fixtures  4 ,  5 , the distance between which is identical to that measured between the holes  7 . Also, an eyelet  31  is produced in the second junction fixture  28 . 
         [0036]    The longitudinal members  22  are fitted in the following manner. Access to the various fixtures is obtained by demounting the external cowls from the pylon  19  or by opening a hatch for passing the tooling through and securing it. This access must be easy and fast so as not to increase the mounting/demounting times. 
         [0037]    The longitudinal members  22  are then disposed on either side of the plate  1  so that, on the one hand, the first and second junction fixtures  26 ,  28  of the central part  25  can be bolted to the respective attachment fixtures  4 ,  5  by means of the complementary holes  7 ,  30  and, on the other hand, the eyelet  31  can be fixed by bolting in a fixed point (not shown) fastened to the wing  3 . 
         [0038]    Alternatively, each longitudinal member  22  can also rest on said fixtures if necessary. 
         [0039]    The personnel can then proceed to the standard installation of the bootstrap type lifting systems  32 . For this purpose, it is first necessary, as shown in  FIGS. 2 to 4 , to translate the forward structure  20  toward the front in order to provide access to hoisting points on the engine structure. 
         [0040]    A first link  33  is fixed transversely in the front end of the front part  23  and a second link  34  is fixed transversely in the central part  25  near the front part  23 . Obviously, these arrangements are such that the first link  33  and the second link  34  are respectively positioned in front of and behind the center of gravity of the engine. 
         [0041]    Note that, the structure of the plate  1  can alternatively be used to secure and structurally reinforce the second link  34 . 
         [0042]    A strap  35  is connected to each of the two ends of the first link  33  and is fixed to a first attachment point (not specifically shown) of the engine. 
         [0043]    A strap  36  is connected to each of the two ends of the second link  34  and is fixed to an attachment point (not specifically shown) of the rear structure  21 . 
         [0044]    Alternatively, the attachment point can be on the structure of the pylon  19 . 
         [0045]    Personnel can then release the one-piece propulsion unit  17  from the plate  1 , which remains fixed in the wing  3 , and then lower said one-piece propulsion assembly  17  in the traditional manner by means of each of the lifting systems  32 , the latter systems enabling the height at four points to be adjusted, each lifting system  32  being independent of the other three. 
         [0046]    Once maintenance operations have been carried out on the engine, it suffices for the personnel first of all to refit the one-piece propulsion unit  17  by means of the lifting systems  32 , then to attach it to the plate  1 , and finally to detach the two longitudinal members  22  from the plate  1  and the wing  3 . 
         [0047]    Alternatively, it is clearly equally possible to demount said front structure  20  instead of translating it. Another variant provides a fixed front structure  20  that and has anchor points (not shown) for the strap  35  and the link  33 . 
         [0048]    Thus these maintenance operations can be carried out very quickly and easily, as well as guaranteeing maximum safety for the personnel responsible for this work. 
         [0049]    Although the invention has been described with reference to particular embodiments, it is clear that it is not limited to these and that it comprises all technical equivalents of the means described and combinations thereof that are within the scope of the invention.