Abstract:
A method and a tool for remotely pivoting an element mounted in a structure is provided. The method includes exerting a lever effect on the element by way of a control bearing on the structure coupled to a connection engaged with the element to cause it to pivot in a pivoting plane. The method also includes applying an angular offset to this connection in a plane different from the pivoting plane, in which the lever effect is produced, in order to render the control remotely operable.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a U.S. National-Stage entry under 35 U.S.C. §371 based on International Application No. PCT/FR2011/051981, filed Aug. 30, 2011, which was published under PCT Article 21(2) and which claims priority to French Application No. 1056891, filed Aug. 31, 2010, which are each incorporated by reference herein in their entirety. 
     TECHNICAL FIELD 
     The technical field relates to a method for remotely pivoting an element and to a tool for implementing this method. The present disclosure applies most particularly when the element is situated in an environment where access is difficult. 
     Accordingly, in its main but not exclusive application, the present disclosure concerns pivoting an aircraft landing gear retaining hook into a locking position. The landing gear of an aircraft in flight is conventionally locked in a folded position in its bay by a gear retaining hook known as the body landing gear (BLG) hook. 
     In the event of a serious hydraulic or electrical problem with the aircraft, an emergency gear control operates the hook to unlock the gear, which can then be deployed for an emergency landing, for example by gravity. In order to test the reliability of this control on an assembly line or in service, the hook is locked manually beforehand with the landing gear deployed. 
     BACKGROUND 
     Until now, such manual locking has been effected by an operative on site. The distance between the strut of the gear and the control for raising the gear is such that this intervention usually takes place in the gear bay. To allow the operative to reach the hook, it is necessary to provide a series of tools such as a safety harness, a reel of line to be fixed to the harness, and an anchorage in the bay for anchoring the reel. Once anchored, the line is pulled out from the reel to recover the clip and attach it to the safety harness worn by the operative, who can then climb onto the landing gear and pull himself up into the landing gear bay. 
     This operation entails safety risks, mobilizes two operatives and necessitates the assembly of a large number of elements, which also takes time and increases the risk of assembly errors. 
     SUMMARY 
     The present disclosure aims to circumvent these drawbacks by enabling remote locking without the operative having to climb onto the gear or into the gear bay. To this end, there is provision for pivoting the hook using lever means having a configuration adapted to the accessibility constraints. 
     To be more precise, the present disclosure provides a method for remotely pivoting an element mounted in a structure, including exerting a lever effect on the element by way of a control bearing on the structure coupled to a connection engaged with the element to cause it to pivot in a pivoting plane and in applying an angular offset to this connection in a plane different from the pivoting plane, in particular perpendicular to that plane, in which the lever effect is produced, in order to render the control remotely operable. 
     Such an offset advantageously enables the element that is to be caused to pivot to be reached remotely when congestion renders the element inaccessible by a direct route, when a rectilinear connection does not allow this and is therefore not usable. Thus in the case of the locking hook described above the presence of the landing gear renders remote access to the hook, i.e. in this case access from the ground, by any tool with a straight handle virtually impossible. 
     According to advantageous particular features, the method of the present disclosure provides for orienting the offset in accordance with multiple angles and/or rendering the connection telescopic to adapt the connection to a given remote access configuration or a particular application. 
     The present disclosure also relates to a tool for implementing this method. Such a tool includes a head provided with a lever arm, a first tubular rod section coupled to the head, a tubular elbow connecting the first section to a second tubular rod section, a control rod in mobile engagement with the second section and flexible means connecting the control rod to the lever arm via a guide connection fastened to the first section. 
     In accordance with certain embodiments: the lever arm may comprise a handle coupled to a central support mounted to rotate about an axis between two guide shoes of the support and the support and the shoes may advantageously be covered with a PTFE covering in order not to damage the element to be pivoted and the structure on which said element is mounted; the elbow is composed of two tubular parts, which may be of substantially equal length, these tubular parts forming between them a particular offset angle, each elbow part being fitted to each corresponding rod section with which it is connected by removable locking means; the rod sections and the elbow parts have openings on annular portions, these openings being superposed when the rod sections and the elbow parts are in their nominal position, and pins serving as removable locking means are introduced transversely via a set of diametrically opposite openings to lock the rod sections in accordance with an elbow angle, at least two sets of openings advantageously being provided on at least one elbow part and the corresponding rod section to vary the orientation of the offset angle and thus to adapt to the congestion of the environment; the elbow parts are articulated to each other about an axis by a nut-and-bolt connection that can be tightened to lock it in accordance with a particular offset angle. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present disclosure will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and 
         FIG. 1  and  FIG. 1A , show a general view of a landing gear in its bay retained in position by a locking unit, the unit being enlarged in  FIG. 1A ; 
         FIG. 2  shows, a general view of one example of a rod in accordance with the present disclosure; 
         FIG. 3  shows, a view of the head of the tool and the first rod section in accordance with  FIG. 2 ; 
         FIG. 4  shows, a view of the elbow connecting the rod sections in accordance with  FIG. 2 ; 
         FIGS. 5A and 5B  show, top and front views of an alternative version of the connecting elbow; 
         FIG. 6  shows, a view of the head and the first section engaged in the locking unit, and 
         FIG. 7  shows, an interior view of the landing gear bay with a hook and a rod in accordance with the present disclosure installed to pivot the hook into the closed position. 
     
    
    
     DETAILED DESCRIPTION 
     The following detailed description of the present disclosure is merely exemplary in nature and is not intended to limit the present disclosure or the application and uses of the present disclosure. Furthermore, there is no intention to be bound by any theory presented in the preceding background of the present disclosure or the following detailed description of the present disclosure. 
     Referring to the  FIG. 1  general view, an aircraft landing gear  1  is represented in a position folded into its bay  2 . A locking unit  3  maintains this folded position in the flight phase of the aircraft, in particular by hooking onto the main strut  10  of the gear  1 . As can be seen more precisely in  FIG. 1A , the unit  3  includes a hook  30  in a position locking a bar  11  carried by two arms  12  welded to the strut  10 . The bar  11  is integrated into a housing  32  formed by the hook  30  in the closed locking position. 
     An electrical control (not represented) drives pivoting of the hook  30  in a pivoting plane P 1  between two positions: the closed locking position illustrated by  FIGS. 1 and 1A  and an open position that allows release of the bar  11  and thus of the gear  1 . In the event of an emergency landing, the hook  30  pivots into an open position and the doors  12  of the gear bay simultaneously open, the gear then being deployed into a landing position. 
     In order to verify that the hook is able to open in an emergency to release the gear, the present disclosure provides for testing this control for opening the hook on the ground after manually closing the hook by means of a tool with a special structure enabling the operative to operate remotely.  FIG. 2  shows the overall structure of such a tool  4 . This tool includes a head  41  for connecting it to the locking unit and its hook, a first tubular rod section  42  fastened to the head  41  and mounted on an elbow  43  forming a particular elbow angle “A” in a plane P 2 , and a second tubular rod section  44  coupled at one end  441  to the elbow  43  and to which a control rod  45  is articulated about its axis  451  in the vicinity of the other end  442  of the second section. An offset D is formed between the rod sections  42  and  44 , this offset D being an angle additional to the elbow angle A. 
     A control cord  46  connects the control rod  45  to a handle  411  of the head  41 , passing via a guide pulley  421  fastened to the first section  42 . When the control rod  45  is pulled by the operative in the direction of the arrow F 1  about its axis  451 , the handle  411  of the head is moved along a trajectory (arrow F 2 ) in a plane P 1  by the action of the cord  46 , the plane P 1  being substantially perpendicular to the plane P 2  in the example show here. 
       FIG. 3  shows more precisely the head  41 , to which the first section  42  is fixed directly. The head  41  is composed of a lever arm  410  that comprises a central support  412  and the handle  411  fixed to the support. This support  412  is mounted to rotate on a cylinder  413  connected at the ends to shoes  414  for guiding the support  412  in the locking unit  3  (see  FIG. 6 ). The first rod section  42  is fastened to another cylinder  422  parallel to the cylinder  413  that also connects the two guide shoes  414 . The shoes are advantageously covered with a PTFE covering. The lever arm  410  can thus pivot in the plane P 1 , which coincides with the plane of pivoting of the hook  30 . 
     The support  412  is also covered with a PTFE covering in order not to damage the hook of the unit with which it will be engaged. When the operative pulls on the cord  46 , the handle  411  and the support  412  turn about the tube  413  (arrow F 2 ). A return spring  415  determines the force to be exerted on the cord  46  and returns them to the initial rest position when the operative ceases to pull on the cord. 
       FIG. 3  also shows the guide pulley  421  for guiding the cord  46  as far as the handle  411 , this pulley being fastened to the first section  42 , and a spring-loaded pin  431  disposed transversely in the section  42  to couple this first section  42  to the elbow  43 , as illustrated by  FIG. 4 . In this  FIG. 4 , the elbow  43  connects the first section  42  to the second section  44  through introduction of the sections into each end  433  and  434  of the elbow  43 , the inside diameter of the elbow and the outside diameters of the sections being adapted to enable a tight connection between these tubes. The connection may equally well be made by screw means or the like. In  FIG. 4  the guide pulley  421  for guiding the cord  46  can also be seen. 
     The elbow  43  has a tubular shape that has been curved in the middle beforehand by bending or by welding in accordance with a predetermined obtuse elbow angle A, equal to about 164° in the example to produce about a 16° offset of the first section  42  extended along the same axis by the head  41  relative to the second section  44 . This offset between the two sections is produced in a plane P 2  substantially perpendicular to the plane P 1  of pivoting of the lever arm  411  and the hook  30  (see  FIG. 3 ). 
     In each of the two parts  435  and  436  of the elbow  43 , as in the facing sections  42  and  44 , a set of diametrically opposite openings  5  has been cut. Two spring-loaded pins  431  and  432  are introduced through these openings in order to secure the connections between the elbow  43  and the sections  42 ,  44  whilst remaining removable. 
     Another set of openings  5 ′ is also provided in the rod section  42  in order to lock the assembly of the elbow  43  and the second section  44  by rotation about the first section (one opening  5 ′ is represented as seen through the elbow as if it were transparent). The rotation is effected after the pin  431  has been removed and the elbow is locked by introducing this pin  431  into the openings  5 ′. The plane P 2  of the elbow is then no longer substantially perpendicular to the pivoting plane P 1 . 
     In an alternative version illustrated by the top and front views in  FIGS. 5A and 5B , elbow parts  437  and  438  are articulated to each other about an axis Z′Z by a nut-and-bolt connection  47 ,  48 . The rod sections  42  and  44  are screwed into the elbow parts  437  and  438 . The angle A of the elbow is then made variable by rotation about the axis Z′Z and is locked in accordance with a particular offset by tightening the nut-and-bolt system. This tightening crushes the jaw formed by the advanced portions  437   a  of the elbow part  437  against the advanced portion  438   a  of the elbow part  438 . 
     Referring to  FIG. 6 , showing partially the interior of a bay  2  without the gear, the central support  412  of the head  41  is conformed so that it can be integrated into the housing  32  formed by the hook  30  after guidance with the aid of the shoes  414  bearing on the walls  33  of the unit  3  without remaining locked in this housing. When the operative pulls on the cord  46 , the support  412 , engaged in the hook  30 , turns about the cylinder  413 . The hook  30 , driven by the support  412 , pivots toward the closed position. The tool can then be disengaged from the hook  30 . 
       FIG. 7  is an interior view of the bay  2  of the landing gear  1  equipped with the hook  30 , showing better the effect produced by the offsetting of the tool  4  in accordance with the present disclosure. In this figure, the tool  4  is installed in the unit  3  to allow pivoting of the hook  30 .  FIG. 6  shows clearly that the relative positions of the strut  10  and the control  13  for raising the gear  1  prevent the unit  3  being reached directly i.e. in a rectilinear manner from outside the bay  2 . The offset on the tool  4  allows the head  41  to be integrated without difficulty with the locking unit  3  and the hook  30 . 
     The present disclosure is not limited to the embodiments described and represented. Accordingly, at least one of the rod sections may have sliding telescopic portions  42 . 1 ,  42 . 2 ,  44 . 1 ,  44 . 2  for adjusting the length of the tool to a particular length indicated at arrows l 1 , l 2 . 
     Furthermore, the elbow parts may be articulated to each other by a ball-joint connection that can be locked by jaws in any predetermined orientation within a given solid angle. 
     Furthermore, the elbow may have two or more than two bends of varied shape (from dihedral to continuously curved). A plurality of elbows may be provided, for example a second elbow orientable in a variable plane by any rotation mechanism (screw, bearings, etc.) of one of the parts of the second elbow in a rod section and locking of this rotation by any means (pushbutton, hook, etc.) in order to allow an orientation better suited to a given access configuration. The rotation mechanism and the locking means of that mechanism may alternatively equip the first part  435  of the elbow  43 . 
     Furthermore, the cord may be replaced by any equivalent means: links, bands, blades, etc. The rod sections may be of oblong or rectangular section instead of tubular. 
     Furthermore, the present disclosure applies to any context in which, for reasons of difficult access that may be linked to safety conditions, it is advantageous to operate remotely, for example for construction work high above the ground, or more generally in the field of civil engineering. The support of the head of the tool of the present disclosure is matched to the element to be tilted or pivoted, which element may be a lever, a tie-rod, a nut, etc. 
     While at least one exemplary embodiment has been presented in the foregoing detailed description of the present disclosure, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the present disclosure in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment of the present disclosure, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope of the present disclosure as set forth in the appended claims and their legal equivalents.