Abstract:
This thrust reverser comprises at least two doors ( 1   a,    1   b ) each able to move between a closed position and an open position. These two doors ( 1   a,    1   b ) are adjacent and comprise means of mutual immobilization ( 17, 19 ) positioned on the adjacent edges of these doors and preventing one of said doors from opening as long as the other is closed.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a door-type thrust reverser for a jet engine. 
       BACKGROUND 
       [0002]    As is known in itself, a door-type thrust reverser comprises, as shown in the appended  FIGS. 1 and 2 , at least two doors  1   a,    1   b  each mounted pivoting around an axis  3  between a closed position (shown in  FIG. 2 ) corresponding to a normal operation of the jet engine, and an open position (not shown) owing to which the flow of air circulating in the jet  5  can be deviated toward the outside and upstream of the reverser, thereby making it possible to exert a counter-thrust contributing to the braking of the aircraft  7  (upstream and downstream are defined relative to the direction of circulation of the air in the jet engine, from left to right in  FIGS. 1 and 2 ). 
         [0003]    In order to secure the opening of the doors  1   a,    1   b  as much as possible and thereby avoid any untimely opening of said doors, at least three independent locking systems are provided for each door. 
         [0004]    These three locking systems are generally broken down as follows: a first system locks the upstream portion of each door  1   a,    1   b,  a second system locks the actuating cylinder  9  of said door, and a third system locks a lateral edge of said door. 
         [0005]    These three locking systems for each door, often referred to as “lines of defense”, are required by the legislation in force. 
         [0006]    Although they make it possible to achieve a very high level of safety, these systems have the drawback of being costly and bulky. 
         [0007]    Moreover, a malfunction of the locking system of the cylinder  9  is difficult to detect from the outside, during maintenance operations. 
       BRIEF SUMMARY 
       [0008]    The present invention aims in particular to resolve these problems. 
         [0009]    This aim of the invention is achieved with a thrust reverser comprising at least two doors each able to move between a closed position and an open position, remarkable in that these two doors are adjacent and in that they comprise means of mutual immobilization situated on the adjacent edges of these doors and preventing one of said doors from opening as long as the other is closed. 
         [0010]    These means of mutual immobilization form a very simple locking system, making it possible to hold a first door in the closed position owing to a second adjacent door, in the case of breaking of the other two locking systems of that first door. 
         [0011]    According to other optional characteristics of the thrust reverser according to the invention: 
         [0012]    said means for mutual immobilization are situated on at least one portion of the length of the adjacent edges of said doors; 
         [0013]    said means for mutual immobilization comprise a groove situated on the edge of one of said doors, and a blade situated on the adjacent edge of the other door; 
         [0014]    said means for mutual immobilization are situated periodically on the adjacent edges of said doors; 
         [0015]    said means for mutual immobilization are arranged upstream from said doors; 
         [0016]    said means for mutual immobilization comprise a housing situated on the edge of one of said doors, and a slug situated on the adjacent edge of the other door; 
         [0017]    said means for mutual immobilization have just enough play to allow the opening of said doors: such play makes it possible, in case of failure of the locking systems of one door, to keep the latter part practically flush with the outer envelope of the nacelle; 
         [0018]    said means for mutual immobilization are configured so as to keep said doors integral with each other during part of their opening: this makes it possible, in case of failure of the locking systems of one door, to limit the idle travel of that door during opening of the other door, and thereby to reduce the abutment shock at the end of opening travel of that idle door; 
         [0019]    said means for mutual immobilization are integrated into said doors; 
         [0020]    said means for mutual immobilization are attached on said doors; 
         [0021]    said thrust reverser comprises a beam situated between said doors, extending under said means of mutual immobilization when said doors are closed; 
         [0022]    said thrust reverser comprises an actuating cylinder for each door. 
         [0023]    The present invention also concerns a nacelle for a jet engine equipped with a thrust reverser according to the preceding. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]    Other characteristics and advantages of the present invention will appear in light of the following description, and upon examination of the appended figures in which: 
           [0025]      FIG. 1  illustrates a nacelle for a jet engine, equipped with a door-type thrust reverser according to the prior art, mentioned in the preamble of this description; 
           [0026]      FIG. 2  illustrates one of the doors of this thrust reverser of the prior art, seen in longitudinal cross-section, 
           [0027]      FIG. 3  is a perspective view of half of a door-type thrust reverser according to the present invention, these doors being in the closed position, 
           [0028]      FIG. 4  shows this thrust reverser with its doors open, 
           [0029]      FIG. 5  shows a transverse cross-sectional view of this thrust reverser, the doors being in the closed position, 
           [0030]      FIG. 6  illustrates a detail view of zone VI of  FIG. 5 , 
           [0031]      FIGS. 7 and 8  are views similar to that of  FIG. 6  and correspond to situations where the locking systems of one or the other of the doors have failed, respectively, 
           [0032]      FIG. 9  is a view similar to that of  FIG. 6 , the two doors being shown at the beginning of their opening travel, and 
           [0033]      FIG. 10  is a view similar to that of  FIG. 6  of another embodiment according to the invention. 
       
    
    
       [0034]    In all of these figures, identical or similar references designate identical or similar members of sets of members. 
       DETAILED DESCRIPTION 
       [0035]    In reference to  FIG. 3 , one can see half of a thrust reverser according to the invention, comprising two adjacent doors,  1   a  and  1   b,  each mounted pivoting around respective axes  3   a  and  3   b.    
         [0036]    In  FIG. 3 , the two doors  1   a,    1   b  are shown in the closed position: in this position, the adjacent edges  11   a,    11   b  of these two doors cooperate with each other. 
         [0037]    When these two doors are opened under the action of the respective cylinders  9   a,    9   b,  as visible in  FIG. 4 , the respective edges  11   a,    11   b  of these two doors move away from each other. 
         [0038]    As visible in  FIG. 4 , the two openings  13   a,    13   b  released by the two doors  1   a,    1   b,  are separated from each other by a longitudinal beam  15 , which is covered by the edges  11   a,    11   b  when the doors  1   a,    1   b  are in the closed position (see  FIGS. 3 and 5 ). 
         [0039]    In reference more particularly to  FIGS. 5 and 6 , one can see that the beam  15  can have an essentially trapezoidal section, and that the edges  11   a,    11   b  of the doors  1   a,    1   b  respectively define a groove  17  and a blade  19  inserting itself inside this groove when the doors are in the closed position. 
         [0040]    This groove  17  and this blade  19  can be situated locally upstream from the edges  11   a,    11   b  of the doors  1   a,    1   b,  or preferably extend over practically the entire length of these edges. 
         [0041]    Play J is provided between each of the face of the blade  19  and the corresponding faces of the groove  17 , this play being just enough to allow the blade  19  to come out of the groove  17  upon pivoting of the two doors relative to their respective axes  3   a,    3   b.    
         [0042]    If one assumes that the locking systems of the door  3   b  become ineffective following an incident such as breaking of fan blades of the engine, this door  3   b  becomes idle, i.e. free to pivot around its axis  3   b.    
         [0043]    The blade  19  of the edge  11   b  of this door  1   b  then abuts against the radially outer face of housing  17 , as shown in  FIG. 7 . 
         [0044]    Now, assuming that it is the door  1   a  which becomes idle following a failure of its locking systems, then the radially inner face of the housing  17  abuts against the radially inner face of the blade  19 , as shown in  FIG. 8 . 
         [0045]    One therefore understands that the blade  19  and the housing  17  constitute means of mutual immobilization of the two doors  1   a,    1   b,  making it possible to retain one or the other of these doors that would become idle following a failure of its locking systems. 
         [0046]    This housing  17  and this blade  19  therefore constitute, for each door, a line of defense of extremely simple design, which is added to the other lines of defense constituted by the locking systems of each of these doors. 
         [0047]    In  FIG. 9  we have shown the two doors  1   a,    1   b  during opening: thanks to the play J illustrated in  FIG. 6 , the blade  19  can progressively withdraw from the housing  17 . 
         [0048]    By providing, on one hand, a sufficient circumferential extension for this housing  17  and for this blade  19 , and on the other hand, an extension of these two members over practically the entire length of the edges  11   a,    11   b  of the doors  1   a,    1   b,  one can act such that the complete release of the blade  19  from the housing  17  only takes place at the end of the opening travel of the two doors. 
         [0049]    This particular arrangement makes it possible to ensure that a door becoming idle following a failure of its locking systems can only detach from its adjacent door when these two doors arrive practically at the end of opening travel, thereby minimizing the abutment shock upon opening of the idle door. 
         [0050]      FIG. 10  illustrates another embodiment of the invention, in which the mutual immobilization of the doors  1   a  and  1   b  is obtained using a slug  21  cooperating with a housing  23 , these members being situated preferably near the upstream end of the doors  1   a,    1   b.    
         [0051]    One will note that, in addition to the great simplicity of the immobilization obtained by the arrangement according to the invention, providing that the edges  11   a,    11   b  circumferentially overhang the body of the doors  1   a,    1   b,  as visible in all of  FIGS. 4 to 9 , makes it possible to increase the wind resistance of these doors when they are in the open position, which contributes to the braking action of the aircraft. 
         [0052]    Of course, the present invention is in no way limited to the embodiments described and illustrated, provided as simple examples. 
         [0053]    It is in this way for instance that the principle of doors mutually immobilizing each other in the closed position could be extended to more than two doors, for example three or four doors mutually cooperating with each other.