Patent Abstract:
The invention relates to a locking device ( 11 ) comprising at least one locking system ( 13 ) having at least one locking member ( 17 ) that can be actuated by linking means ( 28 ), the linking means being able to be moved over a defined travel, the movement of the locking means ( 28 ) over a first part of the travel enabling the locking member ( 17 ) to be actuated, alternately between an unlocked position of the locking member ( 17 ) and a locked position thereof, characterized in that the locking system ( 13 ) is designed so that the locking member ( 17 ) remains immobile during the movement of the linking means ( 28 ) over a second portion of the travel, with a view to compensating for the adjustment of the connecting means ( 28 ) and also any malpositioning of the locking system ( 13 ).

Full Description:
TECHNICAL FIELD 
       [0001]    The invention relates to a locking device comprising at least one locking system comprising at least one locking member actuable by connection means, the connection means being displaceable over a specific travel, the displacement of the connection means over a first part of the travel making it possible to actuate the locking member alternately between a position for unlocking the locking member and a position for locking the latter. 
       BACKGROUND 
       [0002]    A locking device of this type is used, in particular, in order to equip a nacelle, itself intended for equipping an aircraft. 
         [0003]    An aircraft is driven by means of a plurality of turbojet engines, each accommodated in a nacelle which likewise houses an assembly of accessory actuating devices associated with its operation and ensuring various functions when the turbojet engine is in operation or is at a standstill. These accessory actuating devices comprise, in particular, a mechanical system for the actuation of thrust reversers. 
         [0004]    A nacelle generally has a tubular structure comprising an air inlet upstream of the turbojet engine, a middle section intended for surrounding a blower of the turbojet engine, a rear section capable of housing thrust reversal means and intended for surrounding the combustion chamber of the turbojet engine, and generally terminates in an ejection nozzle, the outlet of which is located downstream of the turbojet engine. 
         [0005]    Modern nacelles are often intended for housing a double-flow turbojet engine capable of generating, by means of the rotating blades of the blower, a stream of hot air (also called a primary stream) coming from the combustion chamber of the turbojet engine. 
         [0006]    A nacelle generally has an external structure, called an Outer Fixed Structure (OFS), which, with a concentric internal structure, called an Inner Fixed Structure (IFS), defines an annular flow channel, also called a flow section, aiming at channeling a stream of cold air, called a secondary stream, which circulates outside the turbojet engine. The primary and secondary streams are ejected from the turbojet engine at the rear of the nacelle. 
         [0007]    Each propulsive assembly of the aircraft is thus formed by a nacelle and a turbojet engine and is suspended on a fixed structure of the aircraft, for example under a wing or on the fuselage, by means of a pylon or mast attached to the turbojet engine or to the nacelle. 
         [0008]    The rear section of the external structure of the nacelle is conventionally formed from a first and a second half-shell of substantially semi-cylindrical shape, on either side of a longitudinal vertical plane of symmetry of the nacelle, and mounted movably so as to be capable of being deployed between an operating position and a maintenance position for the purpose of giving access to the turbojet engine. The two half-shells are generally mounted pivotably about a longitudinal axis forming a hinge in the upper part (at 12 o&#39;clock) of the reverser. The half-shells are held in the closing position by means of locking devices which are arranged at least along a junction line located in the lower part (at 6 o&#39;clock) and the control of which is accessible by the operator in the lower part. 
         [0009]    The locking device of the abovementioned type has the disadvantages set out below. 
         [0010]    In order to ensure that the locking device functions properly, it is necessary to set the position of the connection means exactly by means of a setting system. Such a setting makes it possible to compensate the positioning faults between the various components, to avoid the effects of thermal expansion and to allow for the manufacturing tolerances of each component. 
         [0011]    To be precise, in the event of poor positioning, it may happen that the locking system is not completely unlocked or locked, this being detrimental in terms of safety. 
         [0012]    Moreover, in such a case, the operator will tend to exert force on the connection means so as to subject them to compressive or tensile stress. 
         [0013]    It is then necessary, in addition to the lengthy setting which is a possible source of operator errors, to overdimension the connection means so that they are not damaged by such stresses. 
       BRIEF SUMMARY 
       [0014]    The disclosure provides a locking device making it possible to avoid an exact setting of the connection means and an over dimensioning of these. 
         [0015]    To achieve this, the invention relates to a locking device of the abovementioned type, characterized in that the locking system is designed in such a way that the locking member remains immobile during the displacement of the connection means over a second part of the travel, for the purpose of compensating the setting of the connection means and the positioning faults of the locking system. 
         [0016]    Thus, only the first part of the travel makes it possible to lock or unlock the locking member. The second part of the travel makes it possible to compensate any offset of the connection means, so as to ensure that, when the connection means have been displaced over their entire travel by the operator, the locking system is effectively locked or unlocked. Thus, it is possible to dispense with setting the connection means. Moreover, the latter are not therefore subjected to high stresses by the operator for the purpose of correctly locking or unlocking the locking system. 
         [0017]    According to one possibility of the invention, the locking member is a bolt. 
         [0018]    According to one characteristic of the invention, the device comprises transmission means linking the connection means to the bolt, the transmission means comprising a track having at least one active part and at least one passive part, the connection means comprising a follower element which is displaced along the track, the transmission means being designed in such a way that the bolt is actuated or remains immobile during the displacement of the follower element along the active part or the passive part of the track respectively. 
         [0019]    Thus, a poor positioning of the follower element with respect to the track has no effect on the actuation of the bolt. To be precise, the displacement of the connection means over their entire travel ensures that the follower element has been displaced along the active part of the track and that, consequently, the bolt has been effectively actuated, this being achieved even if there is a positioning fault of the follower element with respect to the track. 
         [0020]    Advantageously, the track comprises a first and a second passive part arranged on either side of the active part. 
         [0021]    According to one possibility of the invention, the transmission means comprise a cam linking the bolt to the connection means, the cam being designed to be driven in rotation during the displacement of the connection means over only the first part of the travel, the cam being designed in such a way that its rotation brings about the actuation of the bolt. 
         [0022]    According to one embodiment of the invention, the connection means comprise a first end linked to the transmission means and a second end linked to an actuating handle. 
         [0023]    According to another embodiment of the invention, the connection means comprise a first end linked to the transmission means and a second end linked to an additional locking system, the actuation of the additional locking system bringing about the displacement of the connection means. 
         [0024]    The invention relates, moreover, to a turbojet engine nacelle intended for equipping an aircraft and comprising a front air inlet section, a middle section intended for surrounding a blower of the turbojet engine, and a rear section formed from at least one first and one second half-shell which are mounted movably in terms of rotation on an axis, so as each to be capable of being deployed between an operating position, in which the half-shells are close to one another, and a maintenance position, in which the half-shells are apart from one another, characterized in that it comprises at least one locking device according to the invention. 
         [0025]    The invention also relates to an aircraft equipped with at least one nacelle according to the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0026]    In any event, the invention will be understood clearly from the following description, with reference to the accompanying diagrammatic drawing illustrating two embodiments of this locking device by way of example. 
           [0027]      FIG. 1  is a diagrammatic view of a nacelle in longitudinal section; 
           [0028]      FIG. 2  is an exploded view of the rear section of the nacelle in perspective; 
           [0029]      FIGS. 3 and 4  are front views of the locking system in the locking position and in the unlocking position respectively. 
       
    
    
     DETAILED DESCRIPTION 
       [0030]      FIG. 1  illustrates a nacelle according to the invention intended for equipping an aircraft. This nacelle has a tubular structure comprising an air inlet  1  upstream of the turbojet engine, a middle section  2  intended for surrounding a blower of the turbojet engine, a rear section  3  capable of housing thrust reversal means and intended for surrounding the combustion chamber of the turbojet engine, and terminates in an ejection nozzle  4 , the outlet of which is located downstream of the turbojet engine. 
         [0031]    The nacelle is intended for housing a double-flow turbojet engine capable of generating, by means of the rotating blades of the blower, a stream of hot air (also called a primary stream) coming from the combustion chamber of the turbojet engine. 
         [0032]    The nacelle has an external structure  5 , called an Outer Fixed Structure (OFS), which, with a concentric internal structure  6 , called an Inner Fixed Structure (IFS), defines an annular flow channel  7 , also called a flow section, aiming at channeling a stream of cold air, called a secondary stream, which circulates outside the turbojet engine. The primary and secondary streams are ejected from the turbojet engine at the rear of the nacelle. 
         [0033]    Each propulsive assembly of the aircraft is thus formed by a nacelle and a turbojet engine and is suspended on a fixed structure of the aircraft, for example under a wing or on the fuselage, by means of a pylon or mast  8  attached to the turbojet engine or to the nacelle. 
         [0034]    As may be gathered from  FIG. 2 , the rear section  3  of the external structure of the nacelle is formed from a first and a second half-shell  9 ,  10  of substantially semi-cylindrical shape, on either side of a longitudinal vertical plane of symmetry of the nacelle, and mounted movably so as to be capable of being deployed between an operating position and a maintenance position for the purpose of giving access to the turbojet engine. The two half-shells  9 ,  10  are each mounted pivotably about an axis forming a hinge in the upper part (at 12 o&#39;clock) of the reverser. The half-shells  9 ,  10  are held in the closing position by means of locking devices  11  arranged along a junction line  12  located in the lower part (at 6 o&#39;clock). For the sake of clarity in the drawing, only some of the locking devices  11  have been illustrated. 
         [0035]    As is illustrated more particularly in  FIGS. 3 and 4 , the locking device  11  comprises a locking system  13  comprising a body  14  which is fixed with respect to the first half-shell  9  of the nacelle. 
         [0036]    The body  14  comprises a slot  15  making it possible to insert a retaining member  16  secured to the second half-shell, as illustrated in  FIG. 2 . 
         [0037]    A bolt  17  is mounted on the body  14  so as to be displaceable in translational motion along an axis A perpendicular to the slot  15  between a locking position, in which the bolt  17  passes through the slot or projects into the latter, as illustrated in  FIG. 3 , and an unlocking position, in which the bolt  17  is accommodated completely within the body  14  and does not project into the slot  15 , as illustrated in  FIG. 4 . 
         [0038]    The bolt  17  comprises a stud  18  projecting perpendicularly to the axis A and to the slot  15  through an oblong aperture  19  formed in the body  14  along the axis A, so as to allow the displacement of the bolt  17 . According to one embodiment, the bolt comprises two studs  18  radially opposed and extending on either side of the bolt  17  through corresponding apertures  19 . 
         [0039]    Furthermore, the body  14  comprises an oblong orifice or groove  20  extending obliquely with respect to the slot  15  and to the oblong aperture  19  between a first end located in the vicinity of the slot  15  and of the oblong aperture  19  and a second end located in the vicinity of an axis of articulation  21 , the function of which is described below. 
         [0040]    The locking device  13  comprises, furthermore, a cam  22  of elongate shape comprising a first and a second end. The cam is mounted pivotably in the region of its first end on the body  14  of the locking system  13  about the axis  21 . The cam  22  comprises, moreover, an oblong hole  23  in the region of its second end, the stud  18  of the bolt  17  projecting into the oblong hole  23 . More specifically, the oblong hole  23  extends along an axis substantially perpendicular to the axis A of displacement of the bolt  17 . 
         [0041]    The cam  22  comprises, moreover, a track  24  formed by an oblong aperture in the general form of a staircase step. The track thus has three successive parts, namely a first passive part  25 , a second active part  26  and a third passive part  27 , the function of which is described in detail below. 
         [0042]    The locking device likewise comprises a cable  28 , illustrated diagrammatically by a line, comprising a first actuating end. The cable  28  comprises, furthermore, a finger  29  in the region of its second end, the finger  29  being inserted into the track  24  of the cam  22  and into the groove  20  of the body  14 , so as to form a follower element. The cable  28  extends, in the region of its second end, substantially along the axis of the groove  20 , so that said cable is not subjected to any bending stress, but only to tensile and compressive stresses, so that the dimensioning of the cable can be reduced. 
         [0043]    According to the alternative embodiment under consideration, the first actuating end of the cable  28  is attached to a handle or to another conventional locking system or one equipped with a bolt. 
         [0044]    The functioning of the locking device will now be described in more detail. 
         [0045]    When the operator wants to unlock the locking system  13 , he exerts a pull on the cable  28  by means of a control accessible at 6 o&#39;clock, so that the follower finger  29  is displaced along the first passive part  25  of the track  24 . 
         [0046]    The first passive part  25  extends parallel to the axis of the groove  20  in the locking position of the bolt  17 , as illustrated in  FIG. 3 , so that, during the displacement of the follower finger  29  along the first passive part  25 , the bolt  17  remains immobile and ensures the locking of the locking means  23 . 
         [0047]    The follower finger  29  subsequently passes along the second active part  26  of the track  24 . The latter extends obliquely with respect to the groove  20 , so that the displacement of the follower finger  29  causes the pivoting of the cam  22  counterclockwise about the axis  21 , thus simultaneously bringing about the downward displacement of the bolt  17 . 
         [0048]    During this displacement, the stud  18  of the bolt  17  undergoes translational movement in the oblong hole  23  of the cam  22 , thus making it possible to compensate the path deviations between the curved path of the end of the cam  22  attached to the bolt  17  and the straight path A of the latter. 
         [0049]    When the operator continues to exert a pull on the cable  28 , the follower finger  29  is then displaced along the third passive part  27  of the cam  22 , then extending along the groove  20 , so that the bolt  17  remains immobile and ensures the locking of the locking means  23 . 
         [0050]    The locking of the locking system  13  is obtained by means of the reverse sequence of the abovementioned steps. 
         [0051]    According to one embodiment of the invention, the actuating end is equipped with an actuating handle. 
         [0052]    According to another embodiment of the invention, illustrated in  FIG. 2 , the locking system  13  is arranged in an upper junction zone  30  (12 o&#39;clock), the cable  28  connecting the locking system  13  to an additional locking system  31  arranged in the region of the lower junction zone  12 . The additional locking system  31  is designed for carrying out the displacement of the cable  28  when the latter is actuated by the operator. 
         [0053]    Whatever the alternative embodiment under consideration, the locking device  11  makes it possible to avoid an exact setting, even to avoid any setting of the position of the follower finger  29  in the track  24 . To be precise, the exact position of the follower finger  29  is unimportant since the latter necessarily passes along the active part  26  of the track  24 , so that the complete locking or unlocking of the locking system  13  is ensured. Furthermore, the presence of the passive parts  25 ,  27  makes it possible to ensure that the follower finger  29  does not come into abutment against one of the ends of the track  24 , thus preventing the operator from inadvertently subjecting the cable  28  to stress. 
         [0054]    It will be appreciated that the invention is not limited only to the embodiments of this locking device which are described above by way of example, but, on the contrary, embraces all its variants.

Technology Classification (CPC): 4