Abstract:
An assistance device is provided to maneuver of a cover of a nacelle of a turbojet engine. The assistance device includes a joint collinear with an existing joint or hinge for a fitting of the cover, and the joint of the device is rigidly secured to an angled part of which one end bears on the fitting of the cover and of which one point is hinged to a compression spring in order to apply assistance momentum to the fitting of the cover when the cover is raised.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of International Application No. PCT/FR2014/051689, filed on Jul. 1, 2014, which claims the benefit of FR 13/56383, filed on Jul. 1, 2013. The disclosures of the above applications are incorporated herein by reference. 
     
    
     FIELD 
       [0002]    The present disclosure relates to an assistance device for operating a cowl, particularly a fan cowl on a turbojet engine nacelle or a similar device. It also concerns a turbojet engine nacelle equipped therewith. 
       BACKGROUND 
       [0003]    The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. 
         [0004]    Cowls are disposed on turbojet engine nacelles. Such cowls provide the continuity of the aerodynamic skin of the nacelle, when they are closed and during the flight of the equipped aircraft. When the aircraft is on the ground, it undergoes maintenance visits or the like and some inner members of the nacelle must be then accessible through the opening of the protective cowl. 
         [0005]    To this end, the cowl is mounted on one or more hinges mounted on a stationary or support portion of the nacelle. In the case for example of the fan cowl, the size of the cowl is relatively large so that a significant mass must be operated. In addition, the wind resistance is also a problem so that many maintenance operators are mobilized to open a single cowl particularly for large-sized nacelles. 
         [0006]    However, the opening and the closing operations increase the working time of the operator, so that they have a significant cost for the exploitation of a commercial aircraft. 
         [0007]    To overcome this problem, the human intervention in particular must be then limited for handling the cowl. Cylinders may be provided for fully automatic operation, the operator intervention being limited to activate a control lever which actuates the cylinders. 
         [0008]    Such solution cannot be easily implemented on an already existing nacelle, since it requires the setting-up of cylinders and their fastenings on the cowl to be mobilized as well as on the stationary portion relative to the cowl. Furthermore, the actuating cylinders are relatively heavy devices which increase the mass balance of the aircraft, which is to be proscribed. 
         [0009]    Furthermore, the cowl itself has the strictly needed amount of material to achieve the two aforementioned functions of continuity of the aerodynamic skin in flight and of handling for the maintenance operations. It is difficult to add the securing portions of a drive cylinder on such cowl, particularly because the used skin is very low-reinforced and the action of the lifting cylinder could lead to piercing or damaging the cowl. The addition of a reinforcement at the design requires a new setting-up study and further increases the onboard mass of the aircraft. 
       SUMMARY 
       [0010]    The present disclosure provides an assistance device for operating a cowl of a turbojet engine nacelle hinged by means of at least one fitting. The assistance device of the present disclosure includes:
       at least one elbow piece mounted on a hinge coaxial to the hinge of said fitting and having one end bearing on said fitting, and   a compression spring applied on said elbow piece to exert on the cowl fitting an assistance momentum when the cowl is lifted.       
 
         [0013]    According to other features: 
         [0014]    the application of the compression spring on said elbow piece includes a hinge of the elbow piece whose one end carries a bearing piece on the cowl fitting to be assisted; 
         [0015]    the compression spring is applied on a lever which includes a bearing piece on the inner surface of a support of the cowls such as the nacelle pylon; 
         [0016]    the assistance device is U-shaped, the lever including a couple of parallel bars and the elbow piece including two parallel portions; 
         [0017]    the compression spring includes at least one spring selected particularly among gas springs or helical springs; 
         [0018]    the assistance device includes two springs disposed between the U-shaped parallel portions of said elbow piece and the parallel bars of the lever; 
         [0019]    the hinge collinear to an existing hinge or butt hinge for a cowl fitting includes a common shaft together with the hinge of the cowl fitting on which is applied the assistance momentum of the compression spring. 
         [0020]    The present disclosure also concerns a turbojet engine nacelle or the like, the nacelle being of the type including at least one hinged cowl on a support such as the pylon. The nacelle according to the present disclosure includes at least one device for assisting the lifting of the cowl according to the present disclosure, on at least one hinge of a plurality of hinges of said cowl. 
         [0021]    Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
     
    
     
       DRAWINGS 
         [0022]    In order that the disclosure may be well understood, there will now be described various forms thereof, given by way of example, reference being made to the accompanying drawings, in which: 
           [0023]      FIG. 1  shows a nacelle portion of the state of the art having two closed lateral cowls; 
           [0024]      FIG. 2  shows the nacelle portion of the state of the art having the two cowls of  FIG. 1  in the open state; 
           [0025]      FIG. 3  shows the nacelle portion on which it is disposed assistance devices according to one form of the present disclosure; 
           [0026]      FIGS. 4 to 6  show another form of the present disclosure; 
           [0027]      FIG. 7  shows another form of the present disclosure; and 
           [0028]      FIGS. 8 and 9  show another form of the present disclosure. 
       
    
    
       [0029]    The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. 
       DETAILED DESCRIPTION 
       [0030]    The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features. 
         [0031]    In  FIGS. 1 and 2 , it is schematically shown a nacelle portion of the state of the art including two closed lateral cowls. The drawing shows a schematic view in partial section with a left cowl  1 , a pylon or support  3  and a right cowl  3 . The left  1  and the right  2  cowls are hinged on the pylon  3  by a butt hinge  6  or  5  respectively secured from the lower face to the drawing of the pylon  3 . Each butt hinge or hinge  6  or  5  carries an elbow fitting  7  or  4  whose end is secured, for example by screwing on the inner face of the left  1  or the right  2  cowl respectively. 
         [0032]    When the motor contained in the nacelle is in the operating state, both the left  1  and the right  2  cowls are in the closed state ( FIG. 1 ). When the apparatus equipped with the nacelle is under maintenance or control, maintenance agents can open the left  1  or the right  2  cowl by lifting the free edge (lower in the drawing) so that the left  1  or the right  2  cowl pivots around the hinge  6  or  5  respectively. The nacelle is then shown in  FIG. 2 , the left  1  and the right  2  cowls in the open state. 
         [0033]    As noted hereinabove, the cowl mass, its large size on the most significant nacelles, and the wind resistance on the airport maintenance platforms, prevent an easy operation by a single maintenance agent. 
         [0034]    According to the present disclosure, it is possible to add to the existing equipment of the nacelle a device for assisting the operation or the lifting of the cowl by means of limited means, without changing the design of an apparatus and of its nacelle. 
         [0035]    In  FIG. 3 , it is shown one form of such assistance device. The partially shown nacelle includes the same elements as those of  FIGS. 1 and 2  and all references of these two Figures are not illustrated therein to clarify the drawing, even though a mention thereof will be made in the following text. Two assistance devices  10  and  20  are illustrated. However, the assistance device  10 , mounted on the hinge  5  (identical reference to that of  FIG. 1 , but not illustrated in  FIG. 3 ) is in the inactive state, the right cowl  2  having remained closed. The assistance device  20 , mounted on the hinge  6  (same reference to that of  FIG. 1 , but not illustrated in  FIG. 3 ) is in the active state, the maintenance operator having operated the left cowl  1  in the open position. 
         [0036]    The lifting assistance device  10  of the form of  FIG. 3  includes a lever  11  which carries two hinges; respectively on the right a hinge  12 , coaxial to the hinge  5  (see  FIG. 1 ), and on the left a hinge  18 . The lever  11  in the vicinity of the hinge  12 , carries a bearing piece  19  on the inner face (in the drawing) of the pylon or support  3 . The bearing piece  19  may if necessary be secured to said inner face of the pylon  3 , by bolting or otherwise. But, as will be understood through the following dispositions, the balance of the assistance device when constrained by the cowl weight is improved. 
         [0037]    The hinge  12 , coaxial with the hinge  5  ( FIG. 1 ), carries an elbow piece  13 - 15  whose one first portion  15  has one end on the left secured to the hinge  12  and one end on the right secured to another hinge  16 . A second portion  14  of the elbow piece  13 - 15  is secured to the first portion  15  and, if necessary, to the hinge  16  without being however able to rotate relative to the first portion  15 . Finally, the right end of the portion  14  carries a bearing piece  13  on a determined portion of the fitting  4  (see  FIG. 1 ). As the bearing piece  19  aforementioned, the bearing piece  13  of the elbow piece  13 - 15  may, if necessary, be secured to said fitting  4  ( FIG. 1 ), by bolting or otherwise. But, as will be understood through the following dispositions, the balance of the assistance device when constrained by the cowl weight is improved. 
         [0038]    Finally, the lifting assistance device of the cowl  10  includes at least one compression spring whose one end is applied on a portion of the elbow piece. In the form of  FIG. 3 , the application of the spring on the elbow piece bears on a hinge of the elbow piece. In other forms, one end of the compression spring is also applied on a lever. In the described form, the compression spring  17  is mounted by a first end to the aforementioned hinge  18  on the lever  11 , while the end of the movable rod of the compression spring  17  is mounted on the right on the hinge  16  secured to the elbow piece  13 - 15 . 
         [0039]    In one form, the compression spring  17  may be a gas spring having a cylindrical sealing body at one end of which exit a movable rod, which carries a piston intended to pass through the inner volume of the sealing body under pressure of a gas. 
         [0040]    In one form, the cowl  1  or  2  has a mass of 57 kg. The assistance device, the lever  12  and the elbow piece  13 - 15 , may be made of titanium and with a 700 grams gas spring, and it had an overall mass of 1300 grams. The amplitude of the rotational movement of the cowl may be in the range of 60° and the assistance force ranged from 120 N at the beginning of the opening to 340 N in the open position. 
         [0041]    It will now be described the operation of the assistance device  20 , identical to the assistance device  10 , but coupled to the left cowl  1 . When the maintenance operator has unlocked the lock (not shown) of the left cowl  1  on the rest of the nacelle (not shown), he grasps its lower edge and makes it go through a rotational movement  31  around the hinge  6  ( FIG. 1 ). At the same time, the gas spring  27  of the assistance device  20  extends its movable rod  29  in the direction  30 , adding its released compression force at the time of lifting of the maintenance operator. The elbow piece of the assistance device  20 , analogous to the elbow piece  13 - 15  of the assistance device  10 , exerts a compensating momentum on the fitting  7  ( FIG. 1 ) assisting thus the operation of the maintenance operator who can thus act alone. 
         [0042]    Bearing only on the lower face of the pylon and on the fitting  7 , the assistance device  20  exerts no constraint on a small portion of the nacelle. In addition, by designing acute angles relative to the bearing surfaces on the fitting and on the pylon, the assistance device remains in place due to the bearing pieces, even without the use of fasteners, only lying on the hinge  6  with which the device shares a hinge axis. 
         [0043]    The device of the present disclosure has only a minor addition to the embedded devices in the nacelle so that its setting-up may not pose a problem on an existing nacelle. Similarly, its integration at the design of a new nacelle does not lead to additional constraints. 
         [0044]    Besides the conformation of the bearing pieces ( 13  and  19 ; assistance device  10 ) with the lower face of the pylon and with the fitting ( 4 ;  FIG. 1 ), the assembly of the assistance device of the present disclosure requires only changing the existing hinge on the fitting connecting the cowl to the lower face of the pylon. In practice, this hinge consists of one or more shafts on the hinge axis which engages in the corresponding piercing of the fitting  4  or  7  and of a portion fastened to the lower face of the pylon. In one form, this shaft is removed and replaced by a longer shaft which also engages in the hinge  12  (device  10 ) secured to the elbow piece  13 - 15  and to the lever  11 . One form will be described further. 
         [0045]    In  FIGS. 4 to 7 , it is shown three perspective views of another form of the present disclosure, when mounted on an existing nacelle. The concerned nacelle portion is viewed from the front when mounted on the pylon  34 . It is shown two assistance devices  40  on the cowl  36  of the left and  50  on the cowl  39  of the right. The cowl  36  of the left is secured to a fitting  35 , invisible end of which is hinged by a shaft to a stationary fitting secured to the inner face of the pylon  34 . Similarly, the right cowl  39  is secured to a fitting  35  an visible end of which is hinged by a shaft on a stationary fitting secured to the inner face of the pylon  34 . 
         [0046]    An assistance device  40  is mounted on the fitting  35  of the left cowl  36  and an assistance device  50  is mounted on the fitting  38  of the right cowl  39 . The disposition of these two assistance devices may be analogous to that of the form of  FIG. 3 . 
         [0047]    In  FIG. 4 , the cowls are in the closed position, while they are open in  FIG. 5 . It is noted the presence of a reinforcing bar  37  which join the stationary fittings secured from the lower face to the nacelle of the pylon, the stationary fittings contributing to the conventional hinge of the left cowl  36  with the fitting  35  and the right cowl  39  with the fitting  38 . The particular section of the reinforcing bar  37  drives an adapted profile on the bearing piece  47 , analogous to the bearing piece  19  of the assistance device  10  described in  FIG. 3 . 
         [0048]    In the form of  FIGS. 4 to 6 , the assistance device is U-shaped, so that the lever  11  and the elbow piece  13 - 15  of the assistance device  10  of the form of  FIG. 3  are doubled on the assistance device  40  of the form of  FIG. 4 . Thus, on the left of the assistance device  40 , the equivalent of the lever  11  consists of two parallel bars whose only the front bar  42  is visible and they are joined particularly by the bearing piece  47 . Similarly, the spring  17  of the form of  FIG. 3  is doubled by two identical springs  45  and  46  and the elbow piece  13 - 15  is also doubled by two similar and parallel portions of which only the rear portion  43  has been referenced and which are connected by a bearing piece  44  of the fitting  35 , the bearing piece  44  being analogous to the bearing piece  13  of the assistance device  10  of the form of  FIG. 3 . The ends of the two springs  46  and  45  are hinged on suitable hinges respectively of the two portions of the elbow piece  43 - 44  and of the double lever  42 . 
         [0049]    Finally, a common shaft  41  of the assistance device  40  together with the fitting  35  enables supporting the assistance device  40  on the nacelle and its assistance operation. In  FIG. 5 , which is identical to  FIG. 4 , the two cowls  36  and  39  are shown in the open state, the two assistance devices being in the expanded state, the springs are completely extended. 
         [0050]    In  FIG. 6 , it is shown the assistance device  40 , just before its assembly on the fitting  35 . For this purpose, the original shaft of the fitting  35  hinge on the pylon is removed, the cowl  36  being in the lifted position. The assistance device  40  is placed by the counterpart hinge  56 ,  57 , the two springs  46 ,  45  being in extended state. It is simply a matter of putting a longer shaft  41  through the piercing  52  provided for this purpose. The two parallel arms of the stirrup consisting of the two parallel  42  front and  59  rear levers are placed so that their left ends carrying piercings  56  and  57  pass to the outside of the stationary fitting of the inner face of the pylon  34 . In this form, the stationary fitting of the inner face of the pylon consists of a forked end of the reinforcing bar  37 . The two arms of the fork forming the stationary fitting each has a piercing  52  or  53  and surround the fitting  35  end on which is mounted the left cowl  36 . 
         [0051]    When all of these components are aligned with the common axis of the hinge to be reformed, the shaft  41  is inserted into the piercings set and the change operation of the cowl hinge assembly is achieved, at the same time that the assistance device  40  is installed in the nacelle. It is simply a matter of closing the left cowl  36  to put the two compression springs  46  and  45  in compression and ready to assist the subsequent opening operation. 
         [0052]    In  FIG. 7 , it is shown another form of an assistance device, when it is mounted on the right cowl  39  of the same type of nacelle as that of  FIGS. 4 to 6 . The assistance device is similarly U-shaped with two bars  65  and  66  joined to the left on a bearing piece  73  on the reinforcing bar  37 . The other ends of the bars  65  and  66  which are analogous to the lever  11  of the form of  FIG. 3  carry the elbow piece  68 - 72  consisting of two parallel portions  68  and  71  as in the case of the form of  FIGS. 4 to 6 . The two parallel portions  68  and  71  of the elbow piece  68 - 72  are joined by a bearing piece  70  of the fitting  38  mounted on the right cowl  39 . 
         [0053]    The space between the two parallel portions  68  and  71  of the elbow piece  68 - 72  receives a cap  72  hinged on an axis  69  passing through the two parallel portions  68  and  71 . The cap  72  is intended to receive the free end of the movable rod of a single compression spring  67 , whose body  67  is itself hinged to the left on the parallel bars  65  and  66 . 
         [0054]    The assembly and the operation of the stirrup of the assistance device of the form of  FIG. 7  are identical to those of the form of  FIGS. 4 to 6 . 
         [0055]    In  FIG. 8 , it is shown another form of an assistance device according to the present disclosure. The nacelle on which it is installed is identical to that of  FIGS. 4 to 7  and has the same reference numbers. It is noticed, however, that the left  36  and the right  39  cowls, each carries three hinged fittings on the forked ends—such as that shown in  FIG. 6  on three reinforcing bars  85 ,  86  and  87 . In the form of  FIG. 8 , a single assistance device is disposed on the hinge of the central reinforcing bar  86 . An assistance device  75 - 80  is mounted on the left according to a similar scheme to that of the form of  FIG. 3 , on the common hinge  75  together with the fitting  35  of the left cowl  36 , while an assistance device  81 - 83  identical to the left assistance device  75 - 80  is mounted on the common hinge together with the fitting  38  of the right cowl  39 . 
         [0056]    The assistance device of this form differs from the previous forms in that it incorporates a helical spring  79  or  82  instead of a gas spring and that it does not get back the form of a stirrup, then being mounted on one side of the axis  75  which forms the common hinge of the elbow piece  78  (respectively  83 ), of the lever  76  (respectively  81 ) carrying the helical spring  79  (respectively  82 ) of the assistance device which acts on the fitting  35  (respectively  38 ), and the fitting  35  itself on the stationary fitting at the end of the reinforcing bar  86 . 
         [0057]    In  FIG. 9 , it is shown a bottom view of the form of  FIG. 8 , but in which an assistance device has been added to each of the three fittings of both left  36  and right  39  cowls, namely the devices  90 ,  92  and  94  for the three fittings of the right cowl  39  and the devices  91 ,  93  and  95  for the three fittings of the left cowl  36 . 
         [0058]    The devices of the other forms aforementioned can also be distributed over all the fittings and the hinges of either cowls or limited to some of them. The compression springs used to produce the assisted-opening momentum are of all types comprising gas springs and helical springs.