Abstract:
This grid thrust reverser cover comprises a seal support and a seal mounted in this support by means of two fastening lugs, this seal being capable of interacting with a diversion edge of this thrust reverser. At least one of the said lugs is turned up and the said support has a section matching that defined by the said lugs.

Description:
TECHNICAL FIELD OF INVENTION 
     The invention relates to a cascade thrust reverser cowl equipped with a deflection edge seal. 
     BRIEF DISCUSSION OF RELATED 
     In such a thrust reverser  1  having a grid-like cascade of vanes  3 , which reverser is represented schematically in appended  FIG. 1 , there must be provided a seal  5  mounted on the cowl  7  and coming into contact with the deflection edge  9  when the reverser is in the closed position. 
     Specifically, in this position, air flowing through the cold air duct  11  under the effect of a fan (not shown) of a turbofan engine (not shown) must not be able to escape from this duct toward the cascade of vanes  3 : the seal  5  provides this sealing. 
     Under the effect of the pressure exerted by the deflection edge  9 , which pressure is symbolized by the arrow  13  in  FIG. 2 , the lower lug of this seal has a tendency to come out of the seal support  17  mounted on the cowl  7 : the seal thus no longer performs its sealing function, and the performance losses are then considerable. 
     The work required to refit the seal  5  in its support  17  is costly and makes it necessary to immobilize the aircraft. 
     In an attempt to overcome this problem, the solution arrived at involves adhesively bonding the seal  5  to the bottom of its support  17 : however, this is not satisfactory, firstly because, in spite of the presence of adhesive, the seal has a tendency to come out of its support, and secondly because the adhesive complicates the operations of replacing the seal in the case of wear. 
     BRIEF SUMMARY OF THE INVENTION 
     The invention provides a cascade thrust reverser cowl comprising a seal support and a seal mounted in this support by means of two fastening lugs, this seal being designed to cooperate with a deflection edge of this thrust reverser, said cowl being distinguished by the fact that at least one of said lugs is turned up, and by the fact that said support has a cross section matching that defined by said lugs. 
     According to other optional features of the reverser cowl according to the invention:
         said two lugs are turned up: the presence of two such lugs allows an optimum retention of the seal;   said lugs extend toward the outside of this seal: this form is suitable for placing the seal on a C-shaped support (see below);   said lugs extend toward the inside of this seal: this form is suitable for placing the seal on a support in the form of a rail or tube (see below);   this seal has a symmetrical cross section: such a seal is adapted to absorb symmetrically distributed forces;   this seal has an asymmetrical cross section: such a seal is adapted to absorb asymmetrically distributed forces;   this seal comprises reinforcing means situated in said at least one lug: these reinforcing means allow a better holding of the seal in its support;   said reinforcing means comprise a wavy structure: such reinforcing means allow a longitudinal deformation of the seal that is appropriate when this seal is fastened to parts having skew surfaces;   said wavy structure is formed in a material chosen from the group comprising a plastic material, a metallic material, glass fibers and carbon fibers;   at least one of the lugs of said seal has notches allowing the insertion of a tool;   said support has a C-shaped cross section, the branch of this C that is intended to cooperate with said at least one turned-up lug being folded toward the inside of this C: this form is designed to cooperate with a seal whose lugs extend toward the outside;   the two branches of said C are folded toward the inside of this C: the presence of two such branches allows an optimum retention of the seal when this seal is intended to be subjected to forces coming from all directions;   the branches of said C have openings: these openings make it possible to check whether the lugs of the seal have been correctly placed in the support;   this support takes the form of a rail or tube: this support form is designed to cooperate with a seal whose lugs extend toward the inside of the seal.       

    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       Other features and advantages of the invention will become apparent in light of the description below and from an examination of the appended figures, in which: 
         FIG. 1  is a schematic view of a cascade reverser provided with a seal of the prior art, this figure having been discussed in the preamble of the present description, 
         FIG. 2  is a detail view of the region II in  FIG. 1 , this  FIG. 2  having likewise been discussed in the preamble of the present description, 
         FIG. 3  is a view of the cross section of a seal support according to the present invention, 
         FIG. 4  is a view of the cross section of a seal designed to cooperate with the support in  FIG. 3 , 
         FIG. 5  is a view of this support and of this seal when they are assembled, 
         FIG. 6  is a view of a variant of this seal incorporating reinforcing means, 
         FIG. 7  is a plan view of the reinforcing means incorporated in the seal in  FIG. 6 , 
         FIGS. 8 to 11  are schematic views indicating the sequence of operations for fitting the seal according to the invention in its support, 
         FIG. 12  represents a variant of the seal according to the invention, 
         FIG. 13  represents reinforcing means incorporated in the seal in  FIG. 12 , 
         FIGS. 14 to 17  indicate the sequence of operations for fitting this seal variant in its associated support, 
         FIG. 18  represents, in perspective, a variant of a support for the seal in  FIGS. 12 to 17 , 
         FIG. 19  is a view of the cross section of this seal when it is installed in the support in  FIG. 18 , 
         FIG. 20  represents another variant of the seal according to the invention installed in a suitable support, 
         FIG. 21  represents another variant of a seal support, and 
         FIG. 22  represents the cross section of another variant of a seal designed to cooperate with the support in  FIG. 21 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Reference will now be made to  FIG. 3 , in which it can be seen that, according to a first variant, a seal support  117  according to the invention can have a substantially C-shaped cross section, one  119  of the two branches of this support being folded toward the inside of the C, as is represented. 
     This support  117  is designed to accommodate the seal  105  represented in  FIG. 4 , which seal comprises a body  106  of substantially circular cross section, and two lugs  108 ,  110  extending toward the outside of the body  106 , one  108  of these two lugs being turned up toward the body  106 , as is represented in  FIG. 4 . 
     The thickness X of this lug is designed to correspond to the degree of opening X of the branch  119  of the support  117  (see  FIG. 3 ). 
     Furthermore, the radius R of the lug  108  is designed to allow the seal  105  to be fitted inside the support  117 , as represented in  FIG. 5 . 
     What is meant by “turned up” within the context of the present invention is that the lug  108  is curved over on itself and that the branch  119  of the support  117  covers more or less the whole of this lug in such a way as to prevent this lug from disengaging from this branch under the action of forces oriented particularly in the direction of the arrow F shown in  FIG. 5 . 
     To enable the lug  108  to be held optimally inside the branch  119  of the support  117 , provision can be made for the reinforcing means  112  to be embedded in the material forming the seal  105  (typically silicone). 
     As represented in  FIG. 7 , these reinforcing means can typically comprise a member having a wavy shape that is formed in a plastic material, or else in a metallic material, or else in a glass fiber-based or carbon fiber-based material. 
     The sequence of operations for fitting the seal  105  inside the support  117  can be seen in  FIGS. 8 to 11 :
         the lug  108  is first introduced inside the branch  119  of the support  117  ( FIGS. 8 and 9 ),   the lug  110  is then compressed in the direction of the lug  108  so as to introduce this lug  110  into the other branch of the support  117  ( FIG. 10 ),   finally, the seal is relaxed such that the lug  110  of the seal  105  takes its place in the other branch of the support  117  ( FIG. 11 ).       

     In the variant represented in  FIG. 12 , the seal  205  according to the invention has a substantially symmetrical cross section, that is to say that the two lugs  208 ,  210  extend toward the outside of the body  206  of this seal and are turned up in the direction of this body. 
     As above, a reinforcing member  212  can be provided that has waves embedded in the material forming the two lugs  208 ,  210  of the seal  205  (see  FIG. 13 ). 
     The sequence of operations for fitting this seal variant according to the invention is substantially analogous to the sequence for the seal mentioned above:
         one  208  of the two lugs is first positioned inside one of the branches of a support  217  of symmetrical cross section ( FIGS. 14 and 15 ),   the seal is then compressed so as to position the other lug  210  in the other branch of the symmetrical support  217  ( FIG. 16 ), and   the seal  205  is relaxed such that this other lug  210  is correctly lodged inside this other branch of the symmetrical support  217  ( FIG. 17 ).       

     As can be seen from  FIG. 18 , provision can be made for the support  217  to have openings in its two branches, thereby allowing a visual inspection of the correct positioning of the two lugs  208 ,  210  inside these branches. 
     As represented in  FIG. 19 , provision can also be made for the lugs  208 ,  210  of the seal  205  to have notches  222  allowing the insertion of a tool  224  should these lugs not be correctly fitted in the branches of the support  217 . 
     In the variant represented in  FIG. 20 , the seal  305  has two lugs  308 ,  310  which are folded toward the inside of this seal and thus define a cavity  326  designed to encapsulate a support rail  317 . 
     In the variant represented in  FIG. 21 , the support rail  417  has a substantially circular cross section (tube), and the associated cavity  426  of the seal  405  has a corresponding circular cross section. 
     The mode of operation and the advantages of the seal and of its associated support that have just been described are immediately obvious from the foregoing description. 
     The turned-up lug or lugs of the seal (toward the outside:  FIGS. 8 to 19 , and toward the inside:  FIGS. 20 to 22 ) allows or allow the seal to be anchored on its associated support. 
     This anchoring requires an elastic deformation of the seal and, when the seal returns to its original shape, it is retained in a very stable manner in/on its associated support. 
     The use of the reinforcing means  112 ,  212  makes it possible to ensure that the lugs of the seal are held optimally in the associated seal support while allowing a deformation of this seal in its longitudinal direction so as to enable it to hug the profile of the parts with which this seal is intended to cooperate. 
     By virtue of the excellent holding of the seal according to the invention in/on its support means, there is no longer any need to make provision to adhesively bond this seal, thus considerably facilitating the operations of replacing this seal in the case of wear. 
     The choice of the form of the seal and its associated support depends on the direction of the forces to which this seal is subjected. 
     In particular, it will be noted that the variant represented in  FIGS. 3 to 11  is particularly suitable for a situation in which, as visible in  FIG. 5 , the seal is subjected to forces coming essentially from the direction F. 
     By contrast, the variants represented in  FIGS. 12 to 22  are suitable more particularly for situations in which the seal can be stressed by forces coming from all directions. 
     Of course, the present invention is in no way limited to the example which has been described and represented, this example being provided purely by way of example.