Double eccentric connection device and connection system comprising at least one such connection device

Abstract

A double eccentric connection device and a connection system comprising at least one such connection device, the connection device comprising: a main sleeve comprising a central section inserted in an aperture of a fixed lug and two end sections on both sides of the central section, the centers of the outer surfaces of the two end sections being offset from the center of the outer surface of the central section; and two bushings, each of which is inserted through the aperture of the U-shaped clip and mounted on one of the end sections, each bushing having an outer surface centered off the center of its inner surface, so that the connection device comprises two eccentric elements, each of which has an inner surface centered off the center of its inner surface. An alignment error between the aperture passing through the fixing lug and the through aperture of the U-shaped clip can be compensated by appropriate angular positioning.

Description

TECHNICAL FIELD

[0001] The present invention relates to a device for connecting a fixing lug to a U-shaped clip and to a connection system comprising at least one such connecting device. BACKGROUND

[0002] The present invention applies to the assembly of structural parts or elements of an aircraft, in particular of a transport aircraft.

[0003] More particularly, although not exclusively, the present invention applies to the assembly of the central portion of a monoplane and in particular to the connection of the so-called keel beam in the belly of the aircraft to the fuselage of the aircraft. The various interface elements engaged between the keel beam and the fuselage transmit the compression and tensile loads resulting from the bending of the fuselage during take-off, landing and flight and / or the loads resulting when the aircraft is sliding along the ground, these loads being transmitted from the main structure to the keel beam.

[0004] During the assembly of two structural elements, it is necessary to provide an adjustment capacity in order to correct alignment errors of the alignment between the parts to be assembled, in particular between the mutually cooperating U-shaped clip and the fixing lug.

[0005] In order to be assembled to the keel beam, the adjustment capacity is generally obtained by imparting to the interface parts at the fuselage a length or width adapted to allow the counter-drilling during assembly. The assembly method employed is relatively long and requires a large number of manual operations, such as in particular drilling, separation, deburring and cleaning, possibly also packaging, and assembly using a large number of fixings. For each part of the keel beam attached to the fuselage, this assembly method must be repeated at each of its ends. Furthermore, this method is carried out in non-ergonomic positions.

[0006] There is therefore still a need to be able to have a reliable solution to assemble two members and more particularly a U-shaped clip and a fixing lug which makes it possible to correct misalignments and to mitigate the above-mentioned drawbacks. SUMMARY

[0007] The object of the present invention is to propose a solution which meets the above-mentioned needs. The present invention relates to a device for connecting a fixing lug to a U-shaped clip.

[0008] According to the invention, the connecting device comprises at least:

[0009] - a main sleeve comprising a central section intended to be inserted into the through orifice of the fixing lug, the central section having a circular outer surface in cross section with a first diameter, the main sleeve further comprising two end sections connected to said central section, respectively one on each side of the central section, the outer surface of the two end sections having a circular shape in cross section with a same second diameter, said second diameter being different from said first diameter, the center of said circular outer surface of the two end sections being offset from the center of the circular outer surface of the central section; and

[0010] - two bushings, each of the two bushings being mounted on one of the end sections, having a circular inner surface in contact with the circular outer surface of the corresponding end section, and intended to be inserted into the through orifice of the U-shaped clip, each of said bushings having an outer surface which is circular in cross section and the center of which is offset from the center of the circular inner surface of the bushing.

[0011] Thus, according to the application, the connection device comprises two eccentric elements: a first eccentric element is obtained by the mutual offset of the end sections and the central section of the main sleeve, and a second eccentric element is obtained by the mutual offset of the inner surface and the outer surface of the bushings. These two eccentric elements make it possible to adjust the relative positioning of the outer circular surface of the central section with respect to the outer circular surface of the end sections in such a way that any misalignment between the through orifice of the fixing lug and the through orifice of the U-shaped clip can be compensated for, by angular (rotational) positioning of the main sleeve, and thus of the central section (within the orifice of the fixing lug), and by angular (rotational) positioning of the bushings with respect to the sleeve.

[0012] Thus, with a limited number of manual operations, the fixing lug can be simply and quickly connected to the U-shaped clip, as described below, while at the same time correcting any misalignment that can exist.

[0013] Advantageously, the central section of the main sleeve is provided, at one of its longitudinal ends, with a radially projecting flange.

[0014] In a preferred embodiment, the connection device comprises an inner sleeve housed within said main sleeve, the outer surface of which is in contact with the inner surface of the main sleeve. Furthermore, advantageously, the connection device comprises at least one retaining nut associated with each bushing, the at least one retaining nut applying pressure to the bushing under the action of a nut screwed onto a threaded section of the inner sleeve, so as to prevent its translation.

[0015] Furthermore, advantageously, the connection device comprises a nut and a washer for at least preventing the translation of the main sleeve.

[0016] Furthermore, advantageously, at least one of the following elements has a frustoconical shape:

[0017] - a main sleeve;

[0018] - a bushing;

[0019] - an inner sleeve.

[0020] The application also relates to a connection system for connecting a first structural element to a second structural element.

[0021] According to the application, the connection system comprises at least one fixing lug fixed to the first structural element and at least one U-shaped clip fixed to the second structural element, and the fixing lug is connected to the U-shaped clip using a connection device as described above, in which the central section of the main sleeve is inserted into the through orifice of the fixing lug, and in which each of the two bushings is mounted in the through orifice of the U-shaped clip, the angular positioning of the main sleeve and the angular positioning of the bushings relative to the main sleeve being adjusted so as to compensate for any misalignment between the axis of the through orifice of the fixing lug and the axis of the through orifice of the U-shaped clip.

[0022] In one particular embodiment, the first structural element corresponds to a portion of a fuselage and the second structural element corresponds to a keel beam of an aircraft, the connection system comprising a plurality of fixing lugs fixed to the portion of fuselage and a plurality of U-shaped clips fixed to one end of the keel beam, and each of the fixing lugs is connected to one of the U-shaped clips using a connection device as described above.

[0023] The application also relates to a method for assembling the connection system described above.

[0024] According to the application, the method comprises at least the following steps:

[0025] - a step of assembling a main sleeve into the orifices of the fixing lug and the U-shaped clip, the main sleeve being angularly positioned in a first position;

[0026] - a step of assembling a bushing, each bushing being angularly positioned in a second position, the first position and the second position being adjusted so as to compensate for any misalignment between the axis of the through orifice of the fixing lug and the axis of the through orifice of the U-shaped clip; and

[0027] - a step of assembling a clamping and retaining element.

[0028] Advantageously, the method also comprises a step of assembling an inner sleeve inside the main sleeve. BRIEF DESCRIPTION OF DRAWINGS

[0029] The attached drawings will enable a person skilled in the art to understand how the application can be implemented. In these drawings, identical references denote similar elements.

[0030] Figure 1 is a schematic partial perspective view of the connection of one end of a keel beam to a portion of the fuselage of an aircraft, in particular using four connection devices.

[0031] Figure 2 is a longitudinal section through a particular embodiment of a connecting device which connects a partially depicted fixing lug to a likewise partially depicted U-shaped clamp.

[0032] Figure 3 is a cross-sectional view showing a main sleeve forming a first eccentric element.

[0033] Figure 4 is a cross-sectional view showing a bush forming a second eccentric element.

[0034] Figure 5 is an enlarged view of a portion of Figure 2 showing the protruding flange and the positioning of the individual elements of the connecting device.

[0035] Figure 6 is an enlarged view of a portion of Figure 2 showing the positioning of the individual elements of the connecting device.

[0036] Figure 7 is a block diagram of a method of assembling such a connecting system. DETAILED DESCRIPTION

[0037] The connecting device (hereinafter referred to as "device 1") shown in one particular embodiment of the invention and schematically depicted in Figure 2 forms part of a connecting system (hereinafter referred to as "system 2").

[0038] The system 2 is intended for connecting two structural elements of an aircraft, in particular a transport aircraft, together. In the preferred example, as depicted in Figure 1 , the system 2 is intended to connect one end 3A of a keel beam 3 to a portion of the fuselage 4 of the aircraft. In this exemplary embodiment, the system 2 comprises four devices 1, as described below.

[0039] Each device 1 of the system 2 is intended to connect a fixing lug 5 to a U-shaped clamp 6. In the example of Figure 1 , each fixing lug 5 is fixed to the fuselage portion 4 and each U-shaped clamp 6 is fixed to the end section 3A of the keel beam 3.

[0040] The fixing lug 5 is provided with a circular through-opening 7 Figure 2 . As for the U-shaped clamp 6, it generally has the overall shape of a U, with two branches 8A and 8B Figure 2 , each of which is provided with a circular through-opening 9A, 9B.

[0041] In the following description, elements that are the same as and related to the two branches 8A and 8B (of device 1) are identified by the same reference numerals, which are added with the suffix A or B, where suffix A indicates that the element is associated with branch 8A and suffix B indicates that the element is associated with branch 8B.

[0042] Device 1 is designed to insert into orifices 7, 9A and 9B and to compensate for any misalignment of orifice 7 relative to orifices 9A and 9B, i.e. any misalignment in the transverse plane (hereinafter specified) between the centers of the circular orifices 7, 9A and 9B.

[0043] For this purpose, the device 1 includes a main sleeve 10 made into a single part, which includes a central section 11 with a longitudinal axis XX. This central section 11 is intended to be inserted into the through hole 7 of the fixing lug 5.

[0044] In the context of this invention:

[0045] - The adjective "longitudinal" refers to the direction of the axis XX. Figure 2 ), which also corresponds to the direction of orifice 7;

[0046] The adjectives "inner" and "outer" are defined relative to the radial direction of this axis XX; that is, in the case of "inner," it refers to being closer to the axis XX, and in the case of "outer," it refers to being farther away from the axis XX.

[0047] - The adjective "horizontal" refers to a plane orthogonal to axis X.

[0048] The central section 11 of the main sleeve 10 has a circular outer surface 12 in cross-section, which has a center C1 and a diameter D1, as shown below. Figure 3 As depicted in the text.

[0049] like Figure 2 As depicted, the main sleeve 10 also includes two end sections 13A and 13B, which are arranged longitudinally on each side of the central section 11.

[0050] The outer surfaces 14A and 14B of the two end segments 13A and 13B have the same circular shape in cross-section, having a center C2 and a diameter D2, as shown below. Figure 3 As depicted in the text. Furthermore, this diameter D2 is smaller than the diameter D1.

[0051] like Figure 3 As depicted, the centers C2 of the circular outer surfaces 14A and 14B of the two end segments 13A and 13B are offset by a distance in the transverse plane relative to the center C1 of the circular outer surface 12 of the central segment 11. This offset (distance L1) allows for the creation of a first eccentric element, as described below.

[0052] The device 1 also comprises Figure 2 two bushings 16A and 16B, as depicted in Each of these bushings 16A and 16B is intended to be inserted into one of the through orifices 9A and 9B of the clevis 6.

[0053] Each of these bushings 16A and 16B is mounted on one of the end sections 13A and 13B. Thus, the bushing 16A is mounted on the end section 13A in such a way that its circular inner surface 17A( Figure 4 ) is in contact with the circular outer surface 14A( Figure 3 ) of the end section 13A. Likewise, the bushing 16B is mounted on the end section 13B in such a way that its circular inner surface 17B( Figure 4 ) is in contact with the circular outer surface 14B( Figure 3 ) of the end section 13B.

[0054] Furthermore, each of the bushings 16A and 16B has an outer surface 18A, 18B, circular in cross section, with a center C3 and a diameter D3, and an inner surface 17A, 17B, also circular in cross section, with a center C4 and a diameter D4, as depicted in Figure 4 .

[0055] For each of the bushings 16A and 16B, the center C3 of the circular outer surface 18A, 18B is offset in the transverse plane with respect to the center C4 of the circular inner surface 17A, 17B by a distance L2, as depicted in Figure 4 . This offset (distance L2) makes it possible to create a second eccentric element.

[0056] Thus, the device 1 thereby comprises two eccentric elements: a first eccentric element obtained by the mutual offset of the end sections 13A and 13B of the main sleeve 10 and of the central section 11; and a second eccentric element obtained by the mutual offset of the inner surfaces 17A and 17B and of the outer surfaces 18A and 18B of the bushings 16A and 16B. The effects of the two eccentric elements are combined, as described below.

[0057] The distance dii between the outer surface 12 of the central section 11 and the outer surface 13A, 13B of each of the bushings 16A, 16B varies in the transverse plane as a function of its angular position, i.e. as a function of its position along the outer surface 12, which is curved in cross section. Figure 3Reference segment R1 is drawn through centers C1 and C2. At one end A1 along reference segment R1, distance d1A between outer surface 12 and outer surfaces 13A, 13B is the longest; and at the other end B1, distance d1B between outer surface 12 and outer surfaces 13A, 13B is the shortest. Between these two angular positions, distance d1i decreases from distance d1A to distance d1B by rotating in the direction shown by arrow F1 (or in the opposite direction to this arrow F1).

[0058] Distance d2i between outer surfaces 18A, 18B and inner surfaces 17A, 17B of each bushing 16A, 16B varies in the transverse plane as a function of its angular position, i.e. as a function of its position along outer surfaces 18A, 18B, which are curved in cross-section. Figure 4 Reference segment R2 is drawn through centers C3 and C4. At one end A2 along reference segment R2, distance d2A between outer surfaces 18A, 18B and inner surfaces 17A, 17B is the longest, while at the other end B2 along reference segment R2, distance d2B between outer surfaces 18A, 18B and outer surfaces 17A, 17B is the shortest. Between these two angular positions, distance d2i decreases from distance d2A to distance d2B by rotating in the direction shown by arrow F2 (or in the opposite direction to this arrow F2).

[0059] These two eccentric elements make it possible to adjust the relative positioning between circular outer surface 12 of central section 11 and circular outer surfaces 18A and 18B of bushings 16A and 16B in such a way as to be able to compensate for the alignment errors between through orifice 7 of fixed lug 5 and through orifices 9A and 9B of U-shaped clip 6, by appropriate angular positioning of main sleeve 10, and therefore of central section 11, in orifice 7 of fixed lug 5, this positioning being obtained by rotating main sleeve 10, and by angular positioning of bushings 16A and 16B relative to main sleeve 10, this positioning being obtained by rotating bushings 16A and 16B, the two angular positionings matching and cooperating with each other.

[0060] As a non-limiting example, offset L1 between centers C1 and C2 is between 0.5 and 3 mm, and is preferably approximately 1.5 mm, and offset L2 between centers C3 and C4 is between 0.5 and 3 mm, and is preferably approximately 1.5 mm, enabling device 1 to compensate for an offset (between the centers of circular orifices 7, 9A and 9B) of between 1 and 6 mm, preferably up to 3 mm.

[0061] As depicted in Figure 2 Orifice 7 in fixed lug 5 is provided with a ring 19 mounted in tight fit, as described below. This ring 19 has substantially the same length as orifice 7 (i.e. the dimension along axis X-X).

[0062] Moreover, the orifice 9A in the branch 8A of the U-shaped clip 6 is provided with a ring 20A mounted in tight fit. This ring 20A has substantially the same length (i.e. the dimension along the axis X-X) as the orifice 9A. Likewise, the orifice 9B in the branch 8B of the U-shaped clip 6 is provided with a ring 20B mounted in tight fit. This ring 20B also has substantially the same length as the orifice 9B.

[0063] Moreover, the orifice 7 in the fixing lug 5 is provided with a ring 19 mounted in tight fit.

[0064] Moreover, a gap 21A of for example about 1.5 mm in length is provided between the bushing 16A and the ring 19, so that the two elements can be prevented from coming into contact with each other. Likewise, a gap 21B of for example about 1.5 mm in length is provided between the bushing 16B and the ring 19, so that the two elements can be prevented from coming into contact with each other.

[0065] The main sleeve 10 has an inner surface 24 which defines an inner cavity of slightly frustoconical shape with a small taper angle (with respect to the axis X-X), which, by way of indication, is comprised between 0.5 mm and 5 mm, and for example is about 1 mm. The diameter of the frustoconical shape increases in the direction indicated by the arrow I1 in Figure 2 , i.e. from the branch 8A towards the branch 8B.

[0066] Moreover, the central section 11 of the main sleeve 10 is provided at one of its two longitudinal ends with a radially outwardly projecting flange 22, as depicted in Figure 5 , in enlarged form. Figure 5 An enlarged portion S1 of Figure 2 is shown.

[0067] This projecting flange 22 delimits a housing 25 Figure 5 . This housing 25 enables the central section 11 to be longitudinally blocked with respect to the ring 19.

[0068] Moreover, the device 1 comprises bushings 23A and 23B. Each bushing 23A, 23B is positioned between the ring 20A, 20B and the bushing 16A, 16B. The inner surface 41A, 41B of each bushing 23A, 23B has a slightly frustoconical shape with a small taper angle (with respect to the axis X-X), which, by way of indication, is comprised between 0.5 mm and 5 mm, and for example is about 1 mm. The bushings 23A and 23B are mounted in clearance fit. Moreover, they are inserted as described below until they come into contact with the ring 19, as can be clearly seen in Figure 5 for the bushing 23B.

[0069] The outer surface 18A, 18B of each of the bushings 16A and 16B has a slightly frustoconical shape with a small taper angle (with respect to the axis X-X), which, by way of illustration, is comprised between 0.5 mm and 5 mm, and is for example of the order of 1 mm. Each of the bushings 16A and 16B is mounted between the end section 13A, 13B and the sleeve 23A, 23B. The diameter of the frustoconical shape of the bushing 16A increases in the direction indicated by the arrow I2 from the branch 8B to the branch 8A, while the diameter of the frustoconical shape of the bushing 16B increases in the direction indicated by the arrow I1. Figure 2 The diameter of the frustoconical shape of the bushing 16A increases in the direction indicated by the arrow I2 from the branch 8B to the branch 8A, while the diameter of the frustoconical shape of the bushing 16B increases in the direction indicated by the arrow I1.

[0070] In a preferred embodiment, the device 1 also comprises an inner sleeve 26, produced as a single piece, which is housed inside the main sleeve 10.

[0071] The inner sleeve 26 comprises:

[0072] - a central section 27 provided with a slightly frustoconical outer surface 28 having a small taper angle (with respect to the axis X-X), which, by way of illustration, is comprised between 0.5 mm and 5 mm, and is for example of the order of 1 mm; and

[0073] - two end sections 29A and 29B, respectively positioned on each side of said central section 27, in the longitudinal sense. Each end section 29A, 29B is provided with a threaded outer surface 30A, 30B.

[0074] The outer surface 28 of the central section 27 of the inner sleeve 26 is in contact with the inner surface 24 of the main sleeve 10. The inner sleeve 26 is pushed longitudinally into the main sleeve 10, as described below.

[0075] As Figure 6 (depicting Figure 2 an enlarged portion S2 of the device 1), the device 1 also comprises a gasket 31 which is in contact, on one side, with the end section 13A of the main sleeve 10 and, on the other side, with a nut 32.

[0076] The nut 32 is screwed onto the threaded section 30A of the inner sleeve 26 so that it moves in the direction indicated by the arrow I1 in Figure 2 and Figure 6 The gasket 31, held in place by the nut 32, prevents the main sleeve 10 from translating in the direction of the arrow I2.

[0077] The two bushings 16A and 16B are assembled together so that they are radially stopped against the bushings 23A and 23B. These elements thus retain the possibility of translating with respect to each other (along the axis X-X). In order to prevent this translation, the device 1 comprises retaining (and clamping) nuts 33A, 33B intended to exert a pressure on the bushings 16A, 16B, asFigure 2 As depicted in the text.

[0078] Therefore, the retaining nuts 33A and 33B are moved by conventional nuts 35A and 35B (e.g., hexagonal), and washers 34A and 34B are arranged between the retaining nuts 33A and 33B and the retaining nuts 35A and 35B.

[0079] Nut 35A is screwed onto the threaded section 30A of the inner sleeve 26, so that it is in Figure 2 The movement in the direction indicated by the middle arrow I1 causes the retaining nut 33A and therefore the bushing 16A to move in the same direction. This translational movement, combined with the slightly tapered shape of the bushing 16A, will cause the bushing 16A to expand, thereby blocking the bushings 16A and 23A.

[0080] Similarly, nut 35B is screwed onto the threaded section 30B of inner sleeve 26, so that it is in Figure 2 The movement in the direction indicated by the middle arrow I2 causes the retaining nut 33B and therefore the bushing 16B to move in the same direction. This translational movement, combined with the slightly tapered shape of the bushing 16B, will cause the bushing 16B to expand, thereby blocking the bushings 16B and 23B.

[0081] use Figure 7 The method P described herein is used to assemble the device 1 as described above and the system 2 including the device 1.

[0082] With regard to this method P, when two structural elements to be assembled (such as...) Figure 1 When the example keel beam 3 and fuselage section 4) are in place, and the fixing elements for the mating U-shaped clamps 6 and fixing plates 5 are also in place at each connection point, measurement step E1 is performed first. The purpose of this measurement step E1 of method P is to measure any possible deviation between the center of the orifice 7 of the fixing lug 5 and the center of the orifices 9A and 9B of the branches 8A and 8B of the U-shaped clamp 6.

[0083] Next, step E2 is performed to assemble bushings 23A and 23B, during which bushings 23A and 23B are positioned in rings 20A and 20B of branches 8A and 8B of U-shaped clip 6.

[0084] Subsequently, in assembly step E3, the main sleeve 10 is inserted from the branch 8B side of the U-shaped clamp 6. Figure 2 Insert it into the holes 7, 9A and 9B of the fixing lug 5 and U-shaped clip 6 in the direction of the middle arrow I2.

[0085] The main sleeve 10 is positioned at an appropriate angle to account for measurement deviations between the centers of orifices 7, 9A and 9B.

[0086] The main sleeve 10 is inserted until it comes into contact with the flange (or shoulder) 22. Then, the washer 31 can be fitted on the side of the branch 8A which is in contact with the end section 13A of the main sleeve 10.

[0087] Next, in a subsequent assembly step E4, the inner sleeve 26 is inserted into the main sleeve 10 from the side of the branch 8B of the clevis 6 in the direction of the arrow I2, and at the same time the nut 32 is positioned against the washer 31 to receive the threaded section 30A of the inner sleeve 26. Figure 2

[0088] The inner sleeve 26, which has a slightly truncated conical shape with a small taper angle, which is between 0.5 mm and 5 mm, and for example approximately 1 mm, as an illustration, expands the main sleeve 10 and thus blocks the main sleeve 10 in all directions.

[0089] In a subsequent assembly step E5, the bushings 16A and 16B are installed in the branches 8A and 8B of the clevis 6. During this step E5, the bushings 16A and 16B are positioned at the appropriate angular position in the rings 23A and 23B to take into account the measured deviation between the centres of the apertures 7, 9A and 9B.

[0090] The angular positioning of the main sleeve 10 (and thus of the central section 11 of the aperture 7 of the fixing lug 5) and the angular positioning of the bushings 16A and 16B relative to the main sleeve 10 are chosen in such a way as to obtain the relative positioning between the circular outer surface 12 of the central section 11 and the circular outer surfaces 18A and 18B of the bushings 16A and 16B in such a way as to be able to compensate for the alignment errors between the through aperture 7 of the fixing lug 5 and the through apertures 9A and 9B of the clevis 6.

[0091] Finally, in the assembly step E6 of the method P, the final elements are installed to clamp and hold. More specifically, in this step E6, the holding nut 33A, the washer 34A and the nut 35A are installed at the end of the branch 8A. The nut 35A is screwed onto the threaded section 30A of the inner sleeve 26 so that it moves in the direction indicated by the arrow I1 in Figure 2 which the washer 34A and the holding nut 33A are moved in the same direction and block the bushing 16A.

[0092] Furthermore, in this step E6, the holding nut 33B, the washer 34B and the nut 35B are installed at the end of the branch 8B. The nut 35B is screwed onto the threaded section 30B of the inner sleeve 26 so that it moves in the direction indicated by the arrow I2 in Figure 2 which the washer 34B and the holding nut 33B are moved in the same direction and block the bushing 16B.

[0093] ​By means of the device 1 and the method P as described above, the fixing lugs 5 can be quickly and simply connected to the U-shaped clips 6 with a limited number of manual operations, while compensating for any alignment deviations that can exist between the orifice 7 and the orifices 9A and 9B, i.e. any deviation of the centres of the orifices 7, 9A and 9B in the transverse plane.

[0094] The device 1 as described above forms part of a fixing system 2 for fixing a first structural element to a second structural element.

[0095] In the preferred application depicted in Figure 1 , the system 2 is used to fix one end 3A of a keel beam 3 to a portion of an aircraft fuselage 4. Typically, the keel beam 3 has a U-shaped body with a flat, elongated base 36 and two side walls 37 and 38 arranged substantially orthogonally to the base 36 on either side of the base 36. The system 2 comprises a plurality of fixing lugs 5 fixed to the fuselage portion 4 and a plurality of U-shaped clips 6 fixed to the end 3A of the keel beam 3.

[0096] Each of these fixing lugs 5 is connected to one of the U-shaped clips 6 using a connecting device, such as the device 1 described above.

[0097] In the preferred embodiment depicted in Figure 1 , a pair of U-shaped clips 6 is fixed to each of the side walls 37 and 38 of the keel beam 3 at the end 3A.

[0098] For each pair, one of the U-shaped clips 6 is positioned closer to the base 36 than the other U-shaped clip 6. Thus, on the side wall 37, Figure 1 the U-shaped clip 6 provided at the position 40A is positioned closer to the base 36 than the U-shaped clip 6 provided at the position 39A. Likewise, on the side wall 38, the U-shaped clip 6 provided at the position 40B is positioned closer to the base 36 than the U-shaped clip 6 provided at the position 39B.

[0099] Since the load applied to the U-shaped clips 6 provided at the positions 40A and 40B, close to the base 36, is higher than the load applied to the U-shaped clips 6 provided at the more distant positions 39A and 39B, it is conceivable that, for each U-shaped clip 6 provided at the positions 39A and 39B, orifices 9A and 9B of smaller diameter than those of the U-shaped clips 6 provided at the positions 40A and 40B (and also the device 1, the constituent elements of which, and in particular the main sleeve 10 and the bushings 16A and 16B, also have smaller diameters) are provided.

Claims

1. A device for connecting a fixing lug to a U-shaped clamp, wherein said device comprises at least: - a main sleeve (10) comprising a central section (11) intended to be inserted into a through hole (7) of said fixing lug (5), said central section (11) having a circular outer surface (12) in cross section of a first diameter (D1), said main sleeve (10) further comprising two end sections (13A, 13B) connected to said central section (11), one on each side of said central section (11) respectively, said outer surfaces (14A, 14B) of said two end sections (13A, 13B) having a circular shape in cross section of a same second diameter (D2) different from said first diameter (D1), the center (C2) of said circular outer surfaces (14A, 14B) of said two end sections (13A, 13B) being offset in a transverse plane from the center (C1) of said circular outer surface (12) of said central section (11); and - two bushings (16A, 16B), each of said two bushings being mounted on one of said end sections (13A, 13B), having a circular inner surface (17A, 17B) in contact with said circular outer surface (14A, 14B) of the corresponding end section (13A, 13B) and intended to be inserted into a through hole (9A, 9B) of said U-shaped clamp (6), each of said bushings (16A, 16B) having an outer surface (18A, 18B) that is circular in cross section and whose center (C3) is offset from the center (C4) of its circular inner surface (17A, 17B).

2. The device according to claim 1, wherein said central section (11) of said main sleeve (10) being provided at one of its longitudinal ends with a radially projecting flange (22).

3. The device according to any one of the preceding claims, wherein said device comprising an inner sleeve (26) housed inside said main sleeve (10), the outer surface (28) of which is in contact with the inner surface (24) of said main sleeve (10).

4. The device according to claim 3, wherein said device comprising at least one retaining nut (33A, 33B) associated with each of said bushings (16A, 16B), said at least one retaining nut (33A, 33B) applying pressure to said bushings (16A, 16B) to prevent their translation under the action of a nut (35A, 35B) screwed onto a threaded section (30A, 30B) of said inner sleeve (26).

5. The device according to any one of the preceding claims, wherein said device comprising a nut (32) and a washer (31) for preventing at least the translation of said main sleeve (10).

6. The device according to any one of the preceding claims, wherein at least one of the following elements has a frustoconical shape: - said main sleeve (10); - said bushings (16A, 16B); - said inner sleeve (26).

7. A connection system for connecting a first structural element to a second structural element, wherein The system comprises at least a fixing lug (5) fixed to the first structural element (4) and at least one U-shaped clip (6) fixed to the second structural element (3), and wherein the fixing lug (5) is connected to the U-shaped clip (6) using a connecting device (1) according to any one of claims 1 to 6, wherein the central section (11) of the main sleeve (10) is inserted into the through orifice (7) of the fixing lug (5), and wherein each of the two bushings (16A, 16B) is mounted in the through orifices (9A, 9B) of the U-shaped clip (6), the angular positioning of the main sleeve (10) and the angular positioning of the bushings (16A, 16B) relative to the main sleeve (10) being adjusted to compensate for any misalignment between the axis of the through orifice (7) of the fixing lug (5) and the axis of the through orifices (9A, 9B) of the U-shaped clip (6).

8. The connecting system according to claim 7, wherein The first structural element corresponds to a fuselage portion (4) and the second structural element corresponds to a keel beam (3) of an aircraft, wherein the connecting system (2) comprises a plurality of fixing lugs (5) fixed to the fuselage portion (4) and a plurality of U-shaped clips (6) fixed to one end (3A) of the keel beam (3), and wherein each of the fixing lugs (5) is connected to one of the U-shaped clips (6) using a connecting device (1) according to any one of claims 1 to 6.

9. A method for assembling a connecting system according to one of claims 7 and 8, wherein The method comprises at least the following steps: - a step (E3) of assembling the main sleeve (10) in the orifices (7, 9A, 9B) of the fixing lug (5) and of the U-shaped clip (6), the main sleeve (10) being angularly positioned in a first position; - a step (E5) of assembling the bushings (16A, 16B), each of the bushings (16A, 16B) being angularly positioned in a second position, the first position and the second position being adjusted to compensate for any misalignment between the axis of the through orifice (7) of the fixing lug (5) and the axis of the through orifices (9A, 9B) of the U-shaped clip (6); and - a step (E6) of assembling clamping and retaining elements (33A, 33B, 34A, 34B, 35A, 35B).

10. The method according to claim 9, wherein The method comprises a step (E4) of assembling the inner sleeve (26) inside the main sleeve (10).

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