Abstract:
A movable panel such as an aileron is connected to a load-bearing structure such as a wing of an aircraft by hinges which comprise flexible, elastic plates which are juxtaposed and are provided at opposite angles so as to allow the panel to rotate in an easy manner in response to the movements of an actuator; the hinges are, however, rigid in regard to other loads, such as aerodynamic suction loads, such that inadmissible travel of the panel is avoided.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of and priority to French Patent Application No. 13 62434 filed Dec. 11, 2013, the entire disclosure of which is incorporated by reference herein. 
     TECHNICAL FIELD 
     This disclosure relates to an aircraft hinge which is arranged between a movable aircraft panel, which can comprise an aileron or a rudder, and a load-bearing structure associated with the aircraft, which can be a wing or another element connected to the fuselage. 
     BACKGROUND 
     Ailerons and rudders must be freely tilted in order to modify the trajectory of the aircraft. They are therefore pivoted to the structures which bear them by hinges. In general, common type hinges are used, comprising a pivot which is fixed to the load-bearing structure, with which the movable panels engage by rotational pins. The orientation of the panels is determined by the control system for the actuators such as cylinders, the opposite ends of which are pivoted to the panels and to the load-bearing structure, a lever arm being formed on the panels between the axis of rotation and the pivot point of the actuator. It could be considered, however, that the hinges are relatively bulky and heavy. Precautions also have to be taken against the possibility of jamming, since certain hinges have to be used simultaneously in practice in order to support each of the panels, by distributing them over the connection line between the panel and the load-bearing structure: the alignment between the axes of the hinges must be respected perfectly, which makes it necessary to construct one fixed hinge and the others floating, that is to say with play. The freedom, however, has to be reconciled with the need to hold the panel against excessive movements due to aerodynamic forces or gravity, which makes it necessary to add stop devices and makes the assembly more complicated. 
     A simplified device has been proposed in document U.S. Pat. No. 5,463,794 A and consists in a hinge which comprises a flexible plate, the opposite ends of which are embedded in the load-bearing structure and the panel. A pivot point is formed on the hinge indenting it at its middle, so as to give it a reduced thickness locally. The actuators therefore cause the plate to deform appreciably by making it take up variable angles, the apex of which coincides with the location of the indentation. The design hardly seems admissible, however, since the angles formed by the plate have to remain very small in order to avoid plastic mechanical constraints around the indentation. There is also a risk of either fatigue cracking in the case of metal plates, or delamination in the case of composite plates which are formed by stacked layers. 
     SUMMARY 
     An object of the disclosure herein is a different type of hinge, the principle characteristics of which are simplicity of composition joined with reliable mechanical strength, which is likely to improve the traditional design by allowing simplified assemblies between the movable aircraft panel and the structure which carries it, without including the weak points as in the design in the document mentioned above. 
     In a general form, the disclosure herein thus relates to an assembly which comprises a panel of an aircraft and a load-bearing structure of the aircraft and a hinge which is positioned between the panel and the load-bearing structure. The hinge comprises at least two plates which are a flexible, elastic material, each of the plates comprising a first end which is fixed to the panel, a second opposite end which is fixed to the load-bearing structure and a free intermediate part between the panel and the load-bearing structure, and the intermediate parts intersect at an intersection point. The assembly comprises an actuator which is pivoted between the panel and the load-bearing structure and is arranged under the hinge; it also comprises a first pivot point on the load-bearing structure and a second pivot point on the panel, and the actuator comprises a first end which is mounted on the load-bearing structure at the first pivot point and a second end which is mounted on the panel at the second pivot point. The second pivot point of the assembly according to the disclosure is aligned with the intersection point along an axis which is perpendicular to a longitudinal axis of the actuator passing through the first and the second end of the actuator. 
     Thanks to the particular arrangement of the actuator, the rotational angles of the hinge are imposed in a convenient and precise manner. 
     In a preferred manner, the assembly according to the disclosure also comprises a first tongue which is associated with the panel and a second tongue which is associated with the load-bearing structure, such that:
         the first and second tongues each comprise a bottom surface and a top surface;   the first ends of the two plates are each fixed on a surface of the first tongue; and   the second ends are each fixed on a surface of the second tongue, opposite the first ends with regard to the intersection point.       

     According to an embodiment variant, the hinge of the assembly according to the disclosure comprises at least three plates which are arranged at alternate angles along the direction of the connection between the panel and the load-bearing structure. 
     According to another embodiment variant, the hinge of the assembly according to the disclosure comprises a pliable sheet which covers the plates and is fixed by opposite edges to the panel and to the load-bearing structure. 
     According to yet another embodiment variant, the hinge of the assembly according to the disclosure comprises an elastomer block in which the plates are embedded. 
     Finally, the disclosure relates to an aircraft which comprises an assembly according to the disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosure will now be described in more detail in conjunction with the following figures which represent the different aspects and characters of certain embodiments, not excluding any others: 
         FIG. 1  is a view of a first embodiment of the disclosure; 
         FIG. 2  shows the mechanism of the hinge; 
         FIG. 3  shows a perspective view of the hinge; 
         FIGS. 4 and 5  show two embodiment variants; and 
         FIG. 6  shows another embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     In the embodiment described in  FIG. 1 , the trailing edge of a wing  1  is shown in the transverse direction of the aircraft. The wing  1  is extended by an aileron  2  and it is connected to a hinge  3  which will be described in detail by  FIG. 2 . The hinge  3  comprises two elastic, flexible plates  4  and  5  which are juxtaposed in the connection line between the wing  1  and the aileron  2  (in this case the transverse direction of the aircraft), and each of which comprises a first end,  6  and  7  respectively, which is fixed to the aileron  2 , and a second end,  8  and  9  respectively, which is opposite the preceding one and is fixed to the wing  1 . The fixings are made in this case more precisely on the rigid tongues  10  and  11 , which are associated respectively with the aileron  2  and with the wing  1  and are each provided with parallel top and bottom surfaces. The tongues  10  and  11  have appreciably the same thickness, are situated at the same level and are appreciably facing one another when the aileron and the wing are mounted. The first end  8  of the plate  4  is fixed to the bottom surface of the tongue  11  and its opposite end  6  is fixed to the top face of the tongue  10 ; the reverse arrangement exists for the plate  5 , the first end  9  of which is fixed on the top face of the tongue  11  and the opposite face  7  is fixed on the bottom face of the tongue  10 . Thus, the plates  4  and  5  are at opposite angles and, in the sense of reading from left to right, the plate  4  is called the “ascending plate” and the plate  5  is called the “descending plate”. When viewed along the direction of the connection between the wing  1  and the aileron  2 , the plates  4  and  5  have an X-shaped arrangement; the plates  4  and  5  intersect at an intersection point which is given the reference  12 . 
     The device is completed by an actuator  13  (can be seen in  FIG. 1 ), which is a cylinder, a first end  13   a  of which is mounted on the wing  1  at a first pivot point  14  and a second end  13   b  is mounted on the aileron  2  at a second pivot point  15 . The actuator  13  is arranged under the hinge  3  such that:
         the longitudinal axis of the actuator  13  is merged with the straight line passing through the pivot points  14  and  15  and parallel with the longitudinal axis of the hinge  3 , passing through the ends  8  and  7  of the hinge; and   the pivot point  15  of the actuator  13  is aligned with the intersection point  12  of the hinge  3  in a plane perpendicular to the longitudinal axis of the actuator  13 .       

     When a variation in the length of the actuator  13  is controlled, the plates  4  and  5  fold ( FIG. 2 ) and the hinge  3  deforms, thus causing the aileron  2  to rotate around an axis of rotation  16 . The axis  16  is intrinsic to the mounting of the assembly of hinge  3  and the actuator  13  on the wing  1  and the aileron  2 . The axis  16  is aligned with the intersection point  12  and the pivot point  15  and is situated between the two points, generally not far from the intersection point  12  of the plates  4  and  5 . The distance component between the axis  16  and the pivot point  15 , in the direction perpendicular to the direction of extension of the actuator  13 , thus forms a lever arm R, that advantageously can be chosen to be as large as possible in order to exert the same degree of rotational effort on the aileron  2  by a weaker and therefore smaller and lighter actuator  13 . 
     The plates  4  and  5  can be constructed in metal (steel, titanium, etc.), or in composite material, according to whether the characteristics of elasticity, fatigue strength or something else are to be prioritized. 
     The hinge  3  can comprise plates other than those shown in  FIG. 3 : it still comprises one plate  17  similar to the plate  4  and two plates  18  and  22  similar to the plate  5 . Such an arrangement allows the hinge  3  to be strengthened and to increase its stability against twisting movements. For this reason it is advantageous to alternate the “ascending” plates  4  and  17  from the wing  1  to the aileron  2  and the “descending” plates  5 ,  18  and  22 . 
     The appearance of the hinge  3  can be improved if it is covered by a pliable sheet  19  ( FIG. 4 ), the ends of which are fixed to the top faces of the tongues  10  and  11 , or if the plates  4  and  5  are embedded in an elastomer block  20  ( FIG. 5 ). 
       FIG. 6  shows an embodiment variant, applicable to a spoiler panel  21 , which rests against a flap  23  which extends the wing  1  toward the rear. The characteristics of the preceding embodiment have not been changed; there are just a few variations in form or dimensions of a secondary nature. 
     The disclosure could be applied to any other pivotable aircraft panel, for example to the tailfin. 
     The number of hinges  3 , for each movable panel, will be determined according to safety standards in order to maintain the strength of the connection and careful attention to the kinetics of rotation, even in the case of one of the hinges  3  breaking. The moderate elasticity of the plates  4  and  5  in directions other than the bending, however, allows the number of hinges  3  to be increased without having to utilize floating devices which are intended to restore the isostaticity of the assembly. 
     While at least one exemplary embodiment of the present disclosure has been shown and described, 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 the disclosure described herein. This application is intended to cover any adaptations or variations of the specific embodiments discussed herein. In addition, in this disclosure, the terms “comprise” or “comprising” do not exclude other elements or steps, and the terms “a” or “one” do not exclude a plural number. Furthermore, characteristics or steps which have been described with reference to one of the above exemplary embodiments may also be used in combination with other characteristics or steps of other exemplary embodiments described above.