Abstract:
The invention relates to a thrust reversing device ( 20 ) that includes at least one mobile cowling ( 30 ) mounted in translation in a direction substantially parallel to a longitudinal axis of a nacelle, capable of moving alternatively from a closing position on which it enables the aerodynamic continuity of the nacelle into an opening position in which it opens a passage in the nacelle for the bypassed flow, wherein said mobile cowling ( 30 ) also includes as an extension at least one variable nozzle section ( 40 ) including at least one panel ( 41 ) mounted so as to be capable of rotation, the panel ( 41 ) being adapted for pivoting towards at least one position entailing a variation in the nozzle section ( 40 ) on the one hand, and pivoting towards a position in which it blocks a cold flow jet ( 13 ) formed between a fixed structure of a turbojet fairing ( 12  and the nacelle on the other hand, wherein the mobile cowling ( 30 ) and the panel ( 41 ) are associated with actuation means ( 50 ) capable of activating the respective translation and rotation movements thereof, characterized in that said actuation means ( 50 ) are connected to an upstream end of the panel ( 41 ) by a driving connection rod ( 61 ) capable of moving about anchoring points respectively on the corresponding panel ( 41 ) and the associated actuation means ( 50 ).

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a turbojet engine nacelle comprising a thrust reversing device and a variable nozzle section. 
       BRIEF DISCUSSION OF RELATED ART 
       [0002]    A nacelle generally has a tubular structure comprising an air intake upstream of the turbojet engine, a middle section intended to surround a fan of the turbojet engine, a downstream section housing thrust reversing means and intended to surround the combustion chamber of the turbojet engine, and generally ends with a nozzle, the output of which is situated downstream of the turbojet engine. 
         [0003]    Modern nacelles are intended to house a dual-flow turbojet engine able to generate, via the rotating blades of the fan, a flow of hot air (also called primary flow) coming from the combustion chamber of the turbojet engine, and a cold air flow (secondary flow) that circulates outside the turbojet engine through an annular passage, also called jet, formed between a fairing of the turbojet engine and an inner wall of the nacelle. The two air flows are ejected from the turbojet engine through the rear of the nacelle. 
         [0004]    The role of a thrust reversing device is, during landing of an airplane, to improve the braking capacity thereof by reorienting at least part of the thrust generated by the turbojet engine forward. In that phase, the reverser obstructs the cold air flow and orients the latter toward the front of the nacelle, thereby generating a counter-thrust that is added to the braking of the airplane&#39;s wheels. 
         [0005]    The implementing means to perform that reorientation of the cold flow vary depending on the type of reverser. However, in any case, the structure of a reverser comprises mobile elements that can be moved between, on the one hand, a deployed position in which they open, in the nacelle, a passage intended for the deflected flow, and on the other hand, a retracted position in which they close that passage. 
         [0006]    These moving parts can perform a bypass function or simply an activation function of other bypass means. 
         [0007]    Grid reversers are thus known in which the reorientation of the flow of air is done by cascade vanes, the moving part then consisting of a sliding cowling aiming to expose or cover said grids, the translation of said cowling occurring along a longitudinal axis substantially parallel to the axis of the nacelle. 
         [0008]    Furthermore, aside from its thrust reversing function, the sliding cowling has a downstream side forming the jet nozzle aiming to channel the discharge of the air flows. 
         [0009]    This jet nozzle comprises a series of mobile panels rotatably mounted at a downstream end of the sliding cowling. 
         [0010]    These panels are adapted so as, on the one hand, to pivot toward a position causing a variation in the section of the nozzle and, on the other hand, to pivot toward a position in which, in the thrust reversing situation, they cover the jet in order to deflect the cold flow toward the cascade vanes exposed by the sliding of the mobile cowling. 
         [0011]    The kinematics of actuating such a nozzle is complex. 
         [0012]    In fact, the nozzle being mounted on the mobile cowling, the mobile panels must be associated with an actuating system making it possible, on the one hand, to drive them simultaneously and in a synchronized manner with the mobile cowling during the thrust reversal when the cowling moves to expose the cascade vanes and, on the other hand, to drive them when the cowling is in the retracted position to adapt the optimal section of the nozzle as a function of the different flight phases, i.e. the takeoff, cruising and landing phases of the aircraft. 
         [0013]    Several dedicated actuating systems are known to respond to the particular desired kinematics of the panels of the variable nozzle and the mobile cowling. 
         [0014]    However, they are not satisfactory. 
         [0015]    The reliability of such systems is affected and maintenance difficulties are multiplied. 
         [0016]    In fact, first, in order to ensure guiding of the panels from one position to another, the known actuating systems provide a linear actuator connected to the mobile cowling and the upstream end of one or more panels. 
         [0017]    It has, however, been noted that the movements of each actuator during the rotational movements of the panels are not linear. 
         [0018]    The actuator being subject to forces related to the pivoting of the panels by different angles and, in particular, the pivoting toward the outside of the jet, it may be affected by a bypass phenomenon that creates unwanted deviations in its travel relative to its straight path. 
         [0019]    A first consequence of such a bypass is having actuator kinematics that produce lines of the nacelle during handling requiring a position differential relative to the mobile cowling not parallel to its movement. 
         [0020]    Furthermore, these unwanted deviations can involve modifying the arrangement of the actuator relative to the cascade vanes. 
         [0021]    The structure of the outer structure of the mobile cowling is also altered by the interruption in the continuity of aerodynamic lines due to the outward displacement of the actuator. 
         [0022]    Moreover, in order to ensure pivoting of the panels from one position to the next, driving connection rods are also attached, on the one hand, to the panel, and on the other hand, to a fixed pint of the inner fairing structure of the turbojet engine delimiting the cold air jet. 
         [0023]    However, the presence of these guide connection rods passing through the jet creates many aerodynamic disruptions in a zone with a high speed of movement of the cold air flow through the drag caused. 
         [0024]    The anchor points of these connection rods on the inner structure of the fairing of the turbojet engine also have a drawback. 
         [0025]    In fact, because the mobile structure of the device and the inner fairing structure of the turbojet engine are not independent of one another, the relative deformations experienced by the two structures can create unwanted deviations in the nozzle section during the different flight phases. 
         [0026]    Furthermore, with such a dependency, maintenance operations become more complicated. 
         [0027]    Moreover, in the existing thrust reversing devices, significant movements of the mobile cowling have been observed during the nozzle section variation phase, involving providing structure coverings between the mobile cowling and the fixed structure of the device and increasing the total deployment length of the actuators used. 
         [0028]    These movements also involve a break in the continuity of the aerodynamic lines of the nacelle, in order to improve the retraction phase in the upstream direction of the mobile cowling during pivoting of the panels toward their position increasing the nozzle section. 
         [0029]    Furthermore, the reliability of the sealing systems between the mobile cowling and the fixed structure of the thrust reversing device is affected by the multiplication of these movements. 
       BRIEF SUMMARY 
       [0030]    One aim of the present invention is to offset the problems defined above. 
         [0031]    Thus, one aim of the present invention is to propose a thrust reversing and nozzle section variation device having a simplified structure. 
         [0032]    It is also important to offer a thrust reversing device in which the movements of the actuator during the handling phases of the mobile cowling and panels of the variable nozzle are controlled. 
         [0033]    Another aim of the present invention is to propose a thrust reverser device limiting the movements of the mobile cowling during phases for varying the nozzle section. 
         [0034]    It is also desirable to offer a thrust reversing device that reduces the aerodynamic losses in the jet and effectively ensures sealing between the jet and the nacelle outside. 
         [0035]    Lastly, a final aim of the present invention is to propose a thrust reversing device in which the mobile structure of the device and the inner fairing structure of the turbojet engine are completely separated. 
         [0036]    To that end, the invention proposes a thrust reversing device comprising at least one mobile cowling mounted in translation in a direction substantially parallel to a longitudinal axis of a nacelle, capable of moving alternatively from a closing position in which it enables the aerodynamic continuity of the nacelle into an opening position in which it opens a passage in the nacelle intended for the bypassed flow, said mobile cowling also including as an extension at least one variable nozzle section, said nozzle comprising at least one panel mounted so as to be capable of rotation, the panel being adapted for pivoting toward at least one position entailing a variation in the nozzle section on the one hand, and pivoting towards a position in which it blocks a cold flow jet formed between a fixed structure of a turbojet fairing and the nacelle on the other hand, the mobile cowling and the panel being associated with actuation means capable of activating the respective translation and rotation movements thereof, remarkable in that said actuation means are connected to an upstream end of the panel by a driving connection rod capable of moving about anchoring points respectively on the corresponding panel and the associated actuation means. 
         [0037]    Thanks to the present invention, the movements of the actuating means remain rectilinear in a direction substantially parallel to the longitudinal axis of the nacelle irrespective of the handling phases of the mobile cowling and the panels of the variable nozzle. 
         [0038]    Advantageously, the driving connection rods passing through the cold flow jet of the nacelle are also eliminated. 
         [0039]    According to specific embodiments, the thrust reversing device can comprise one or more of the following features, considered alone or according to all technically possible combinations:
       two driving connection rods surround the actuating means of the panel;   the driving connection rod(s) have a bent shape;   the driving connection rod(s) are associated with a fairing so that the aerodynamic continuity of the outer lines of the nacelle is ensured;   the actuating means comprise a linear actuator made up of three concentric bodies, i.e. a central body, an outer body and an inner body, all three forming shafts, the central body having a first, outer thread able to cooperate with a corresponding thread of the outer body and a second, inner thread able to cooperate with a corresponding thread of the inner body, one of the bodies being blocked in translation and able to be connected to adapted rotational driving means while the other two bodies, each intended to be connected to the cowling and the panel to be driven, are free in translation and blocked in rotation;   the body connected to the rotational means is the central body, the inner body is intended to be connected to the mobile cowling while the outer body is intended to be connected to the connection rod for pivoting the panel;   the outer thread of the central body has a pitch larger than the pitch of the inner thread;   the actuating means comprise two distinct linear actuators respectively associated with the cowling and the panel to be driven, each of the actuators comprising a shaft able to allow, respectively, the panel to pivot toward a position where it obstructs the cold flow jet and toward a position varying the section of the nozzle as well as the translational movement of the cowling;   the actuating means are associated with control means able to perform a controlled differential movement of the panel and the cowling to be driven;   the panel is mounted rotationally mobile around a pivot along an axis perpendicular to the longitudinal axis of the nacelle;   the thrust reversing device also comprises upstream sealing means between the cold flow jet and the outside of the nacelle arranged under bypass means;   the thrust reversing device also comprises downstream sealing means between an inner structure of the cowling and the panel;   the panel is extended by a fixed downstream shroud.       
 
         [0052]    The invention also proposes a dual-flow turbojet engine nacelle comprising a downstream section equipped with a thrust reversing device as mentioned above. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0053]    Other aspects, aims and advantages of the invention will appear upon reading the following detailed description of preferred embodiments thereof, provided as a non-limiting example and done in reference to the appended drawings, in which: 
           [0054]      FIG. 1  is a diagrammatic longitudinal cross-sectional view of a thrust reversing device according to a first embodiment of the present invention in a direct thrust position; 
           [0055]      FIGS. 2   a  and  2   b  are longitudinal cross-sectional illustrations of an actuator of the thrust reversing device of  FIG. 1 , respectively in the retracted position and the deployed position; 
           [0056]      FIGS. 3 to 5  are diagrammatic illustrations in longitudinal cross-section of the thrust reversing device of  FIG. 1  having mobile panels respectively in an open nozzle position, a closed nozzle position and a reverse thrust position; 
           [0057]      FIG. 6  is a diagrammatic illustration in longitudinal cross-section of a thrust reversing device according to a second embodiment of the present invention in a direct thrust position; 
           [0058]      FIG. 7  is a diagrammatic illustration in longitudinal cross-section of the thrust reversing device of  FIG. 6  in a reverse thrust position; 
           [0059]      FIG. 8  is a diagrammatic illustration in longitudinal cross-section of the thrust reversing device of  FIG. 6  showing means for actuating a mobile cowling of said device; 
           [0060]      FIG. 9  is a cross-sectional view of cascade vanes of the thrust reversing device of  FIG. 1  along the plane P′ visible in  FIG. 1 ; 
           [0061]      FIG. 10  is a cross-sectional view of a system for sliding an actuator of the thrust reversing device of  FIG. 1  along the plane P visible in  FIG. 1 ; 
           [0062]      FIG. 11  is a diagrammatic view in longitudinal cross-section of a thrust reversing device according to a third embodiment of the present invention in a direct thrust position; 
           [0063]      FIG. 12  is an enlarged view of zone A of the thrust reversing device of  FIG. 11 ; 
           [0064]      FIG. 13  is a diagrammatic illustration in longitudinal cross-section of a thrust reversing device according to a fourth embodiment of the present invention; 
           [0065]      FIGS. 14 to 16  are diagrammatic illustrations in longitudinal cross-section of a mobile panel of a thrust reversing device according to a fifth embodiment, in the direct thrust, variable nozzle and reverse thrust positions, respectively. 
       
    
    
     DETAILED DESCRIPTION 
       [0066]    A nacelle is intended to form a tubular housing for a dual flow turbojet engine and serves to channel the flows of air it generates via blades of a fan, i.e. a hot air flow passing through a combustion chamber and a cold air flow circulating through the outside of the turbojet engine. 
         [0067]    The nacelle generally has a structure comprising an upstream section forming an air intake, a middle section surrounding the fan of the turbojet engine, and a downstream section surrounding the turbojet engine. 
         [0068]      FIG. 1  shows part of this downstream section, designated by general reference  10 . 
         [0069]    This downstream section  10  comprises an outer structure  11  including a thrust reversing device  20  and an inner engine fairing structure  12  defining, with the outer structure  11 , a jet  13  intended for the circulation of a cold flow in the case of the dual-flow turbojet engine nacelle as presented here. 
         [0070]    The downstream section  10  also comprises a forward frame  14 , a mobile cowling  30 , and a jet nozzle section  40 . 
         [0071]    The mobile cowling  30  is intended to be actuated in a substantially longitudinal direction of the nacelle between a closing position, in which it comes into contact with the forward frame  14  and ensures the aerodynamic continuity of the outer lines of the downstream section  10 , and an opening position, in which it is spaced apart from the forward frame  14 , then opening a passage in the nacelle by exposing air flow cascade vanes  15 . 
         [0072]    The movement of the mobile cowling  30  is done by a rail/slide system known by those skilled in the art. 
         [0073]    Furthermore, the jet nozzle section  40  in the extension of the mobile cowling  30  comprises a series of mobile panels  41  rotationally mounted at a downstream end of the mobile cowling  30  and distributed on the periphery of its jet nozzle section  40 . 
         [0074]    Each panel  41  is adapted on the one hand to pivot toward a position driving a variation of the nozzle section  40  and, on the other hand, to pivot toward a position in which it obstructs the cold flow jet  13  and returns that air toward the cascade vanes  15  that reorient the flow, thereby allowing the thrust reversal. 
         [0075]    Each panel  41  is supported by the mobile cowling  30  via pivot points  42  along an axis perpendicular to the longitudinal axis of the nacelle with the inner portion of the mobile cowling  30  and with said mobile panel  41 . 
         [0076]    According to the invention, the transition from one position of a mobile panel  41  to another is controlled by actuating means  50  connected to the panel  41  via a driving system  60  formed by at least one driving connection rod  61  downstream of their structure. 
         [0077]    The actuating means  50  can activate the movement of the mobile cowling  30  as well as the pivoting of the panel  41  toward a position causing the section of the nozzle  40  to vary and toward a position where it obstructs the cold flow jet  13 . 
         [0078]    They comprise at least one electric, hydraulic or pneumatic linear actuator. 
         [0079]    As illustrated in  FIG. 9 , the actuator can be placed between two fastening lines of the cascade vanes  15 . 
         [0080]    One alternative embodiment can propose an actuator detached from the cascade vanes  15  and that can be oriented in any desired angular position. 
         [0081]    In one embodiment of the present invention illustrated in  FIGS. 2   a  and  2   b , the actuator is a dual-action actuator with a programmed effect  51 . 
         [0082]    Dual action actuator with programmed effect refers to an actuator that can drive the mobile cowling  30  and the panel  41  of the nozzle  40  relative to the fixed forward frame  14  at different speeds, but with a same power drive. 
         [0083]    More specifically, in reference to  FIGS. 2   a  and  2   b , one such actuator  51  comprises a cylindrical base  511  inside which three concentric tubular bodies forming shafts, i.e. an outer body  512 , a central body  513 , and an inner body  514 , are housed. 
         [0084]    The base  511  is intended to be attached to the forward frame  14 , typically via a gimbal joint or ball joint known by those skilled in the art. 
         [0085]    Each of the three tubular bodies  512 ,  513 ,  514  is mechanically engaged with the adjacent body via an outer and/or inner thread. 
         [0086]    More specifically, in the embodiment illustrated in  FIGS. 2   a  and  2   b , the outer body  512  has an inner thread  515  engaged with a corresponding outer thread  516  supported by the central body  513 , the latter also having an inner thread  517  engaged with a corresponding outer thread  518  supported by the inner body  514 . 
         [0087]    Furthermore, the central body  513  is blocked in translation and mounted in rotation on rotational driving means  519  housed in the base  511  of the actuator  51 . The outer body  512  and inner body  514  are blocked in rotation and left translationally mobile, as shown in  FIG. 2   b.    
         [0088]    In fact, the inner body  514  can allow the mobile cowling  30  to move. To that end, the inner body  514  comprises, at its downstream end, a fastening eyelet  520  intended to be fixed to the inner part of the mobile cowling  30 . 
         [0089]    The outer body  512  can allow a panel  41  of the nozzle  40  to pivot. 
         [0090]    It is thus connected by its downstream end to the upstream end of the panel  41  via at least one aforementioned driving connection rod  61  articulated on a transverse drive shaft  521  provided, to that end, on its structure. 
         [0091]    Thus, the movement of the outer body  514  in the upstream direction or in the downstream direction of the nacelle is accompanied by the pivoting of the driving connection rod  61  and, as a result, the panel  41 . 
         [0092]    Concerning the driving system  60  by connection rods, the length as well as the driving points of the connection rod  61  on the upstream end of the mobile panel  41  are adapted to allow the cold flow jet  13  to be effectively covered by the panel  41  in reverse thrust. 
         [0093]    Preferably, the driving points of the connection rod  61  on the upstream end of the panel  41  must be placed as far upstream as possible to produce the greatest possible lever arm with the pivot  42  of the panel  41 , as will be described later. 
         [0094]    This upstream position is limited by the presence of cascade vanes  15 . 
         [0095]    Furthermore, a first embodiment provides a series of two driving connection rods  61  surrounding the outer body  512  of the actuator  51 , i.e. connection rods articulated around a transverse axis on either side of the outer body  512  of the actuator  51 . 
         [0096]    In a second embodiment, a single driving connection rod  61  per panel  41  is necessary. To that end, in one non-limiting example, the driving point of the connection rod  61  on the actuator  51  can be provided on the outer body  512  fastened in a yoke toward the outside of the nacelle. 
         [0097]    Furthermore, in another alternative embodiment, it is possible to providing driving connection rods  61  configured so as to improve the kinematics and play between the pivoting panels and the downstream of the grids  15 . 
         [0098]    Thus, in one non-limiting example illustrated in  FIG. 1 , each driving connection rod  61  can have a bent shape, in order to reduce or even cancel out the need to create a passage downstream of the cascade vanes  15  for the displacement of the connection rod  61 . 
         [0099]    This offer also has the advantage of not interrupting the structure of the cascade vanes  15 . 
         [0100]    Owing to such a driving system, the actuator  51  maintains its straight trajectory along the longitudinal axis of the nacelle during its extension and retraction to move the mobile cowling  30  and the panel  41  of the nozzle  40 . 
         [0101]    During the increase of the nozzle section  40  in particular, the axis passing through the two driving points of the connection rod  61  forms a lever arm with the pivot  42  of the panel  41 , in order to guarantee an effort in the actuator  51  admissible in this phase of varying the nozzle section  40  allowing it not to undergo any bypass in its movements while preserving a rectilinear movement of said actuator. 
         [0102]    Furthermore, advantageously, such a driving system offers great reliability because the number of driving elements present in the cold flow jet  13  is decreased relative to the thrust reversal devices of the prior art. 
         [0103]    In fact, one does away with arranging driving connection rods  61  through the jet  13  to fix them on the inner fairing structure  12  of the engine to cover the jet  13  so as to optimize the reversal of the cold flow. 
         [0104]    The mobile structure  11  of the downstream section  10  also becomes independent of the inner fairing structure  12  of the engine, which facilitates the maintenance operations of the nacelle. 
         [0105]    Moreover, by providing a dual-action actuator with a programmed effect, the mobile cowling  30  and the mobile panels  41  are actuated with kinematics specific to them during adjustment of the nozzle section variation  40  or during the thrust reversal. 
         [0106]    In fact, due to the different thread pitch between the different bodies  512 ,  513 ,  514  of the actuator  51  and a same power drive, one automatically adapts the travel and movement speeds of the mobile cowling  30  and the mobile panel  41  between them and relative to the forward frame  15 . 
         [0107]    This offers the advantage of being able to limit the movements of the mobile cowling  30  to very small or no movements during the pivot phases of the mobile panel  41  in a position making it possible to increase or reduce the section of the jet nozzle  40 . 
         [0108]    The operation of the thrust reversal device  20  is the following. 
         [0109]    When the actuating means  519  rotate the central body  513 , it transmits that movement to the outer  512  and inner  514  body of the outer  515 ,  516  and inner  517 ,  518  respective threads. 
         [0110]    The outer  512  and inner  514  bodies being blocked in rotation, the driving movement of the central body  513  is transformed into translational movement of the outer  512  and inner  514  bodies. 
         [0111]    The direction and linear speed of translation of each body respectively depend on the direction of rotation of the driving means  519  and the orientation and pitch of each thread. 
         [0112]    In one embodiment of the present invention, the pitch of the outer threads  515 ,  516  is greater than the pitch of the inner threads  517 ,  518 . It follows that the outer body  512  will move in translation at a speed faster than that of the inner body  514  and consequently, the panel  41  will move faster than the mobile cowling  30 . 
         [0113]    The translational movement of the outer body  512  is accompanied by pivoting of the driving connection rod(s)  61  and, consequently, the pivoting of the panel  41 . 
         [0114]      FIGS. 3 to 5  show different positions of the mobile panel  41  as a function of the deployment of the linear actuator with a programmed effect and the degree of movement of the cowling  30 . 
         [0115]    In  FIG. 3 , the mobile cowling  30  is in a closing position covering the cascade vanes  15 . 
         [0116]    It has not been moved, the inner body  514  of the actuator  51  having remained practically stationary. 
         [0117]    The outer body  512  of the actuator  51  has been actuated and retracted in the upstream direction of the nacelle, then driving the pivoting of the mobile panel  41  from its pivot  42  toward the outside of the jet  13 , thereby increasing the section of the nozzle  40 . 
         [0118]    In  FIG. 4 , the outer body  512  of the actuator  51  has been actuated and extended in the downstream direction of the nacelle, then driving the pivoting of the mobile panel  41  around its pivot  42  toward the inside of the jet  13 , thereby decreasing the section of the nozzle  40 . 
         [0119]    During these two phases for adjusting the section of the jet nozzle  40 , the mobile cowling  30  has modified its position closing the cascade vanes  15  little or not at all. 
         [0120]    Furthermore, sealing means upstream and downstream of the mobile cowling  30 , which will be described later, have remained active. 
         [0121]    More specifically, as illustrated in  FIGS. 3 and 4 , the upstream sealing  80  is not affected by the movement of the panel  41  and the play necessary for the relative movements of the mobile cowling  30  relative to the forward frame  15  are not deteriorated. 
         [0122]    In  FIG. 5 , the inner body  514  of the actuator  51  is deployed maximally. The mobile cowling  30  is thus moved in the downstream direction of the nacelle by a length substantially equal to the length of the cascade vanes  15  to be fully open. 
         [0123]    At the same time, the outer body  512  is actuated in the downstream direction, pivoting the panels  41  around its pivot inside the jet  13  so that they fully play their role as thrust reverser covering the jet  13  to force the air to be oriented through cascade vanes  15 . 
         [0124]    As illustrated in  FIG. 5 , due to the selected thread pitches, the outer body  512  moves faster than the inner body  514  and the two driving points of the connection rod  61  and the mobile cowling  30 , respectively, on the actuator  51  tend to come together. 
         [0125]    Advantageously, the translational movement of the mobile cowling  30  and the rotational movement of the panel  41  of the nozzle  40  are automatically synchronized to perform the thrust reversal. 
         [0126]    It should be noted that the embodiment described in reference to  FIGS. 1 to 5  is not limiting. 
         [0127]    Thus, an alternative embodiment can provide for connecting the three tubular bodies of the actuator  51  together to the rotational driving means  519  and the two mobile parts, i.e. the cowling  30  and the panel  41  of the nozzle  40 . Thus, in another non-limiting example, the outer body  512  of the actuator can be adapted to move the mobile cowling  30 , while the inner body  514  can be adapted to move the panel  41  of the nozzle  40 . 
         [0128]    In a second embodiment of the present invention illustrated in  FIGS. 6 to 8 , the actuating means  50  comprise two independent linear actuators  53 ,  55  respectively dedicated to pivoting the mobile panels  41  of the nozzle  40  and moving the mobile cowling  30 . 
         [0129]    These actuators  53 ,  55  are associated with control means (not visible) adapted to activate the pivoting of each panel  41 , independently of one another, toward a position driving the variation of the nozzle section  40  or toward a position where it obstructs the cold flow jet  13  and the movement of the mobile cowling  30 . 
         [0130]    These control means can thus perform a controlled differential movement of the cowling  30  and the panel  41 . 
         [0131]    This offers the advantage of being able to keep the mobile cowling  30  fixed, i.e. in its position closing the cascade grids  15  in direct thrust during the adjustment of the nozzle section  40  by the mobile panels  41 . 
         [0132]    More specifically, in reference to  FIGS. 6 and 7 , a first actuator  53  dedicated to the rotational movement of the panels  41  comprises a cylindrical base  531  inside which a shaft  532  is housed. 
         [0133]    The base  531  is intended to be attached to the forward frame  14 , while the shaft  532  is connected, at its downstream end, to the upstream end of the panel  41  via at least one driving connection rod  61  articulated on a transverse drive shaft provided on its structure. 
         [0134]    This driving connection rod  61  enables the pivoting of the corresponding panel  41  during a movement of the shaft  532  in the upstream or downstream direction of the nacelle. 
         [0135]    This embodiment thus offers the same advantages as the first embodiment described in reference to  FIGS. 1 to 5 . 
         [0136]    In reference to  FIG. 8 , the inner portion of the mobile cowling  30  is connected to the at least one end of a second actuator  55  that can allow the mobile cowling  30  to move upstream or downstream of the nacelle. 
         [0137]    The downstream end of the shaft  552  of the actuator  55  is connected to the inner structure of the cowling  30  while the base  551  of the actuator  55  is fixed, at its upstream end, to the forward frame  14 . 
         [0138]      FIGS. 6 and 7  illustrate different positions of the mobile panels  41 . 
         [0139]    In  FIG. 6 , the mobile cowling  30  is in the closing position covering the cascade vanes  15 . 
         [0140]    Furthermore, the shaft  532  of the first actuator  53  not being extended, the cowling  30  has a usual nozzle section. 
         [0141]    In  FIG. 7 , the control means for two actuators  53 ,  55  are adapted to automatically move, along different travels, the cowling  30  and the panel  41  during the thrust reversal. 
         [0142]    Thus, the shaft  532  of the first actuator  53  has been extended to an adapted length in the downstream direction of the nacelle, driving the pivoting of the panels  41  via the driving connection rod  61  toward the inside of the jet  13  in order to fully play their role as thrust reversers covering the jet  13 . 
         [0143]    The shaft  552  of the second actuator  55  has also been extended to an adapted length in order to drive the cowling  30  in the downstream direction of the nacelle exposing the cascade vanes  15 . 
         [0144]    Furthermore, during adjustment of the nozzle section  40 , the control means are adapted to drive the pivoting of the panels  41  toward the inside or outside of the jet  13 , the cowling  30  remaining fixed thereto. 
         [0145]    In reference to  FIGS. 1 and 3  to  5 , the thrust reversing device also comprises upstream sealing means  80  between the cold flow jet  13  and the outside of the nacelle arranged under the cascade vanes  15 . 
         [0146]    These upstream sealing means  80  are preferably supported by the cowling  30 . 
         [0147]    They comprise a pressure seal  81  preferably supported by an upstream extension  82  of the inner portion of the mobile cowling  30  in contact with the forward frame  14 . 
         [0148]    This makes it possible to ensure sealing contact between the fixed structure of the device  20  and the mobile cowling  30  in the direct thrust phases, i.e. during variation of the nozzle section  40 . 
         [0149]    The upstream sealing means  80  also comprise an upstream apron  83  intended to make the downstream of the cascade vanes  15  partially or completely sealed. 
         [0150]    Said apron  83  extends, upstream of the inner portion of the mobile cowling  30 , toward the cascade vanes  15  as far as the vicinity thereof. 
         [0151]    It can be intended to serve as a shield for the cold flow forcing it to move toward the cascade vanes  15  during the thrust reversal. 
         [0152]    Furthermore, the thrust reversal device  20  comprises downstream sealing means  90  between the cold flow jet  13  and the outside of the nacelle arranged under the panels  41  of the nozzle  40 . 
         [0153]    These downstream sealing means  90  comprise a pressure seal  91  supported by the downstream end of the inner structure of the mobile cowling  30  in contact with a diversion  43  on the inner surface of the mobile panel  41  in order to ensure relative sealing at the interface between the cowling  30  and the panels  41 . 
         [0154]    In one alternative embodiment, the downstream sealing means  90  can be supported by the mobile panel itself  41 . 
         [0155]    Moreover,  FIG. 10  shows an alternative embodiment of the present invention in which the thrust reversal device  20  also comprises means  100  for guiding the linear actuator  51 . 
         [0156]    These guide means  100  are intended to combat buckling in the structure of the actuator  51  due to the presence of connection rods supplying forces not working with the main axis of the actuator  51 . 
         [0157]    More specifically, the outer body  512  of the actuator  51  is mounted mobile in two lateral slide channels  101 ,  102  for translational guiding arranged in the structure of the mobile cowling  30 . 
         [0158]    These slide channels  101 ,  102  are adapted to cover the entire travel length of the outer body  512  of the actuator  51 . 
         [0159]    Each of these is provided with a roller  110  and is intended to receive the transverse drive shaft of the two driving connection rods  61  that surrounds that outer body  512 . 
         [0160]    With such guiding, the outer body  512  of the actuator  51  does not undergo any parasitic force coming from the connection rods  61  and the risk of buckling is eliminated. 
         [0161]    Furthermore, in this alternative embodiment, it is necessary not to create hyperstatic assembly points aligned between the two driving points of the mobile cowling  30  and the panel  41 . 
         [0162]    Radial play is therefore defined for driving of the mobile cowling by the inner body of the actuator. 
         [0163]    In one non-limiting example, the inner body  514  of the actuator  51  is connected to the mobile cowling  30  by a transverse drive shaft placed in an oblong cavity extending in a direction perpendicular to the direction of travel of the cowling  30 . 
         [0164]    Another example includes either the placement of an elastic interface between the two elements, or the addition of a driving connection rod connected on either side of the mobile cowling  30  and the inner body  514  and oriented in the direction of the main axis of the actuator  51 . 
         [0165]    In reference to  FIGS. 11 and 12 , a third embodiment of the present invention proposes associating the driving connection rod(s)  61  of the panels  41  with a fairing  62 . 
         [0166]    This offers the advantage of reducing aerodynamic continuity defects of the outer lines of the nacelle at the fastening of the driving connection rods  61 . 
         [0167]    This fairing has a profile in the shape of a P rotated by 90°. 
         [0168]    Preferably, it is mounted rigidly by the head of the P on the driving connection rod  61 . 
         [0169]    Furthermore, it is placed between the mobile cowling  30  and the panel  41  of the nozzle  40  downstream. 
         [0170]    The bar of the P is mounted in a cutout  31  formed on the outer structure of the mobile cowling  30 , in order to ensure the aerodynamic continuity between the outer structure of the mobile cowling  30  and the panel  41  downstream. 
         [0171]    In  FIG. 13 , a fourth embodiment of the present invention is shown in which a particular diversion  44  is provided for the upstream end of the mobile panels  41  of the nozzle. 
         [0172]    This diversion  44  is intended to enable the continuity of the outer aerodynamic lines of the nacelle during adjustment of the nozzle section  40  and, more specifically, during the section reduction thereof. 
         [0173]    Thus, the upstream end of the panel  41  adjacent to the outer structure of the mobile cowling  30  assumes a recess shape that can be beveled  44 , which allows the panel  41  not to overhang the outer aerodynamic lines of the nacelle when it pivots around its hinge pin  42 . 
         [0174]    The impact of the rotation of the panel  41  on the aerodynamic continuity of the outer lines of the nacelle is minimized. 
         [0175]    Furthermore, in a fifth embodiment of the present invention illustrated in  FIGS. 14 to 16 , a fixed downstream shroud  200  is formed at the downstream end of the mobile panels  41  of the nozzle  40 . 
         [0176]    This offers the advantage of keeping an adjusted direct jet nozzle section in which the section machining deviations are minimized. 
         [0177]    Thus, as illustrated respectively in  FIGS. 15 to 16 , the shroud  200  remains fixed during the change of position of the mobile panels  41  in the position reducing or increasing the nozzle section  40  and when they pivot to cover the cold flow jet  13  reversing the thrust. 
         [0178]    An alternative embodiment provides a shroud  200  adapted to support, at its downstream end, a complementary surface of the chevron type. 
         [0179]    Of course, the invention is not limited solely to the embodiments of the thrust reversing device described above as examples, but on the contrary encompasses all possible alternatives. 
         [0180]    Thus, the present invention can be applied to a thrust reversing device not comprising cold flow cascade vanes.