ARRANGEMENT OF DIAGONAL TUBES ON A MAIN TUBE OF A COMPOSITE GRATING STRUCTURE

Description

Technical field of the invention

[0001] The present invention relates to the technical field of truss beams composed of tubes made of composite material and of joining elements allowing to assemble tubes diagonally on a main tube and relates in particular to an assembly of diagonal tubes on a main tube of a truss beam made of composite material. Technical background

[0002] This study focuses on truss beams used in the construction of air transport structures such as airships, and the connecting elements that enable their assembly. The truss beams of such a structure are designed to withstand significant loads and deformations while remaining as lightweight as possible. Each truss beam consists of three or four main tubes running continuously along its entire length and connected by diagonal tubes. The tubes are generally joined using connecting pieces bonded to the tubes and to each other, ensuring mechanical connection and load transfer. This bonding technique must be extremely precise and consistent to guarantee the reproducibility of the connecting piece's performance.

[0003] US patent 6,056,240 describes a joining piece consisting of two base shells serving as side sections and a cover shell serving as the middle section. The middle section is placed on the tubes and glued, and the two side sections are placed on the glued section so as to encircle the tubes at the joint. The shells, previously coated with glue, are then held under pressure using a clamp. The three-part joining piece ensures the presence of glue between the tubes and the shells, but it is not possible to guarantee that the bond is effective and that there is proper adhesion between the elements.The only way to test the bond is through a mechanical stress test, which carries the risk that the inspection process could compromise the future strength of the bond. This is a significant drawback in the aerospace industry, where each connecting component of a truss beam must ensure the mechanical connection of the tubes and withstand substantial stresses. In practice, these connections are secured by fastening the tubes to the connecting component with a mechanical element such as a rivet. Once in place, this rivet prevents any movement of the connecting component and its various parts relative to the tubes on which it is placed. This method is now standard practice in the aerospace industry, where assemblies are mounted, bonded, and then riveted. This addition represents an extra step in the truss beam manufacturing process, resulting in increased weight and cost.

[0004] Another example of a tube assembly device is described in document US2010192506A1. Summary of the invention

[0005] Therefore, the aim of the invention is to overcome these drawbacks by providing an assembly device comprising a sleeve mounted tightly on the tubes to mechanically connect them and prevent any movement of the assembly device, thus avoiding the use of a rivet to attach the sleeve to the tubes.

[0006] The object of the invention, as claimed in claim 1, is therefore a device for assembling secondary tubes onto a main tube made of composite material comprising a sleeve mounted coaxially on the main tube and provided with two attachment zones located in planes passing through the longitudinal axis of the sleeve, the attachment zones being intended to be rigidly assembled together by means of assembly which keep the sleeve tight on the main tube so that a part of the inner surface of the sleeve is in contact with the outer surface of the main tube, the sleeve comprising means for connecting to at least one secondary tube.The portion of the inner surface of the sleeve in contact with the outer surface of the main tube is peripheral and surrounds a portion of the inner surface of the sleeve that is not in contact with the outer surface of the main tube so as to delimit a reserve between the outer surface of the main tube and the sleeve filled with a filling agent, the assembly device comprising at least one protruding element connected to the sleeve which fits into at least one cavity provided on the outer surface of the main tube, the protruding element being located in the reserve.

[0007] According to other features of the invention: the protruding element is a lug located on the inner surface part of the sleeve; the protruding element is a ring protruding on the inner surface part of the sleeve over at least 90% of the circumference of the sleeve, and the cavity provided on said main tube into which the protruding element is inserted is a non-through groove located on the entire circumference of the outer wall of the main tube; the groove extends into a non-through longitudinal groove located on the outer wall of the main tube; the filler is a polymer material injectable through an orifice and the distance between the outer wall of the main tube and the inner wall part of the sleeve reservoir is between 0.1 mm and 1 mm;The filler is a polymer material positioned on the inner wall portion of the sleeve reservoir in the form of a film, and the distance between the outer wall of said main tube and the inner wall portion of the sleeve has a thickness between 80% and 98% of the film thickness; assembly means for rigidly joining said attachment areas together are bolted or riveted connections or an assembly means in the form of a clip system; the means for attaching the sleeve to at least one secondary tube are common to the assembly means for rigidly joining the attachment areas, the bolted or riveted connection is placed in fixing holes located on the attachment area and at the end of each secondary tube; the means for attaching the sleeve to at least one secondary tube include two cylindrical shells intended to wrap around the ends of the two secondary tubes;Each cylindrical shell comprises at least one projecting element located on the portion of the inner wall of the shells that is not in contact with the outer wall of the secondary tubes; the projecting element connected to each shell of the sleeve is intended to fit into a cavity provided on the outer surface of each secondary tube; each secondary tube comprises at its end a ring with a diameter greater than the diameter of the tube, and each shell has a corresponding housing, complementary to the ring, so that when the sleeve is assembled around the tubes, the ring of each secondary tube is trapped in the housing of each of the shells; the sleeve consists of two identical and symmetrical parts or half-sleeves, connected together by a hinge so as to form an articulated sleeve. Brief description of the figures

[0008] The aims, objects, and features of the invention will become clearer upon reading the following description, made with reference to the drawings in which: [ Fig. 1 ] represents a perspective view of a one-piece sleeve of the assembly device according to the first embodiment of the invention, [ Fig. 2 ] represents a perspective view of the one-piece sleeve of the figure 1 mounted on a main tube, [ Fig. 3 ] represents a perspective view of an articulated sleeve of the assembly device according to the invention in a variant of the first embodiment, [ Fig. 4 ] represents a perspective view of the articulated sleeve of the figure 3 mounted on a main tube, [ Fig. 5 ] represents a perspective view of a one-piece sleeve comprising a ring projecting on its inner surface according to the second embodiment of the invention, [ Fig. 6] represents a perspective view of the main tube onto which the sleeve of the assembly device is anchored according to the second embodiment of the invention, [ Fig. 7 ] represents a cross-sectional view of the main tube and the assembly device according to the invention along plane A of the figure 5 , [ Fig. 8 ] represents a cross-sectional view of the main tube and the assembly device along the same plane A and according to the third embodiment of the invention, [ Fig. 9 ] represents a first variant of the implementation of the means for linking the secondary tubes of the assembly device, [ Fig. 10 ] represents a variant of the embodiment of the diagonal junction points of the assembly device according to the invention. Detailed description of the invention

[0009] Initially, it must be clearly understood that the same reference numbers are intended to identify the same structural elements, parts or surfaces consistently across different figures, as these elements, parts or surfaces can be further described or explained by the whole of the written specification.

[0010] In the following description, the tubes designated as secondary tubes may be the diagonal tubes of a truss beam. The embodiments described show only two per junction, but their number may vary between one and twelve.

[0011] According to the figures 1 and 2The assembly device according to the first embodiment of the invention mainly comprises a sleeve 10 for connecting to one of the main tubes 100 of a truss beam and to two secondary tubes 110 and 120. The sleeve 10 is a single piece and comprises a main body in the shape of a cylinder or, preferably, in the shape of a cylinder truncated at both ends. The sleeve 10 includes two attachment zones 11 and 13 located in planes passing through the longitudinal axis of the sleeve.

[0012] The attachment zones are intended to be rigidly joined together by means of assembly that hold the sleeve tightly onto the main tube 100 such that a portion of the inner surface 12 of the sleeve is in contact with the outer surface of the main tube 100. The sleeve also includes means for connecting to at least one secondary tube 110 and preferably to two secondary tubes 110 and 120. In the case of the embodiment of the figures 1 and 2 The means for connecting the secondary tubes are common to the assembly means for rigidly joining the attachment zones 11 and 13 together and are either bolted connections 61 and 71 or riveted connections placed in fixing holes located on the attachment zone and at the end of each secondary tube 110 and 120. A clip system assembly method may also be used. On the attachment zone 13, a boss 15 is formed to prevent buckling. An identical and symmetrical boss is also formed on the attachment zone 11.

[0013] The sleeve is mounted coaxially on the main tube, and the internal surface portion 12 of the sleeve 10 in contact with the external surface of the main tube 100 is peripheral; that is, it is located on the periphery of the internal surface of the sleeve and thus surrounds the internal surface portion 14 of the sleeve that is not in contact with the external surface of the main tube 100. When the sleeve is assembled on the main tube 100, this internal surface portion 14 delimits a certain closed volume or reservoir 18, located between the external surface of the main tube 100 and the sleeve 10. The internal surface portion 12 in contact with the external surface of the main tube thus forms a barrier between the outside and the inside of this reservoir 18. When the sleeve 10 is in place on the main tube 100, the reservoir 18 is accessible from the outside through at least one opening 19.The reservoir 18 can also be filled from inside the main tube through a hole drilled in its thickness. However, access may be more difficult than from the outside in the case of a long main tube. The internal surface portion 12 protrudes relative to the internal surface portion 14 of the sleeve, creating an offset between the two surfaces of between 0.1 mm and 1 mm, and preferably between 0.2 mm and 0.5 mm. This design ensures sufficient thickness to allow the filler to flow and to achieve the required mechanical performance at the seal formed by the filler.

[0014] The assembly device formed by the sleeve 10 comprises at least one projecting element 81 connected to the sleeve 10, which fits into at least one cavity provided on the external surface of the main tube 100. The projecting element 81 is located on the internal surface portion 14 of the sleeve so as to be situated within the recess 18. The cavity into which the projecting element 81 fits is not shown in the figures 1 and 2This cavity can pass through the tube wall but can also be machined into the tube wall thickness so as not to pass through. The projecting element 81 is in the form of a lug with a diameter between 1 and 10 mm, and preferably between 3 and 7 mm. The sleeve is slipped onto the main tube so that the lug 81 aligns with the cavity provided for this purpose on the main tube 100. Once the sleeve 10 is in place and tightened against the main tube using the assembly means, the connection of the sleeve 10 to the main tube is secured, as is the connection to the secondary tubes 110 and 120. In particular, the projecting element 81 prevents the sleeve 10 from moving or rotating relative to the main tube 100.

[0015] In the assembled position on the main tube 100 shown on the figure 2The sleeve 10 is mechanically connected to the main tube 100 by clamping, using a bolted or riveted connection that maintains the attachment areas 11 and 13 in tight contact with each other. Since the sleeve 10 is shaped like a cylinder truncated at both ends, the outline of the sleeve's bases is elliptical rather than circular, and the contact of the internal surface portion 12 with the main tube occurs over an oblique section of the tube. However, for practical reasons of terminology, and because the sleeve could be cylindrical without departing from the scope of the invention, in this embodiment it is considered to be a circumference. The internal surface portion 12 is in tight contact with the main tube over at least 90% of its circumference, which is almost the entire circumference of the main tube 100, as can be seen in the figures. figures 1 and 2, where we can see that the walls of the sleeve move away from the tube only at the attachment areas 11 and 12. This has the advantage of distributing the clamping stresses as evenly as possible around the tube to transmit the forces over the entire circumference of the main tube and the sleeve.

[0016] The reservoir 18, defining a specific volume, is intended to be filled with a filler. Preferably, a second opening connects the reservoir 18 to the outside and serves as a vent to allow air to escape during filling. The volume of injected filler is slightly greater than the volume of the reservoir 18 to allow visual verification of the actual filling as soon as the filler overflows through the vent. The filler is a polymer such as an epoxy resin, a thermosetting material, or a thermoplastic material, whether injectable or not, structured or not. The polymer may be filled with mineral or metallic particles to improve its resistance to compressive stresses. The filler is intended to fill the entire volume of the reservoir 18 and fill the gaps between the protruding element and the cavity into which it is inserted.The filler material coincides with the internal surface area 14 of the sleeve and the wall of the tube to which it is applied. However, the filler material does not prevent the sleeve 10 from being disassembled and reused. Preferably, the filler material is injected into the reservoir 18 through an orifice 19 provided in the wall of the sleeve 10, when the sleeve 10 is press-fitted onto the main tube 100. The surface area and thickness of the reservoir 18 are known; therefore, the quantity of filler material required to completely fill the reservoir 18 is known and can be calculated at the time of injection to ensure the necessary and sufficient amount is injected. Being able to control the quantity and filling of the reservoir 18 has the advantage of guaranteeing a homogeneous and reproducible distribution of stresses within the filler material.

[0017] THE figures 3 and 4represent an alternative embodiment of the sleeve of the assembly device according to the invention. The assembly device comprises a sleeve 20 made up of two identical and symmetrical parts 201 and 202, or half-sleeves, connected together by a hinge 25. The sleeve 20 is intended to be connected to one of the main tubes 100 of a truss beam and to two secondary tubes 110 and 120. The two parts together thus form the sleeve 20, the main body of which is cylindrical or, preferably, truncated at both ends. The sleeve 20 includes two attachment zones 21 and 23 located in planes passing through the longitudinal axis of the sleeve. The attachment zones are intended to be rigidly joined together by means of fasteners that hold the sleeve tightly onto the main tube 100. The fasteners may be bolted 73 or riveted connections, or means in the form of a clip system.In this tight position around the main tube 100, an internal surface part 22 of the sleeve is in contact with the external surface of the main tube 100.

[0018] The sleeve also includes means for connecting to at least one secondary tube 110 and preferably two secondary tubes 110 and 120. These means consist of two semi-cylindrical portions 261 and 271 attached respectively to each of the half-sleeves. When the sleeve 20 is assembled onto the main tube 100, the two semi-cylindrical portions of each half-sleeve join together to form two cylindrical shells 26 and 27 designed to enclose the ends of the two secondary tubes 110 and 120 and connect them to the sleeve.

[0019] The internal surface portion 22 of the sleeve in contact with the external surface of the main tube 100 is peripheral, that is to say, it is located on the periphery of the sleeve 20 and thus surrounds the internal surface portion 24 of the sleeve that is not in contact with the external surface of the main tube 100 and also includes the internal surface of the cylindrical shells that is not in contact with the secondary tubes 110 and 120. The portion 24 thus extends into the cylindrical shells formed by the assembly of the semi-cylindrical parts 261 and 271. Similarly, the portion 22 also includes a portion located at the edge, therefore on the periphery, of the internal surface of the cylindrical shells located over the entire circumference and at the end of the cylindrical shells.When the sleeve is in place on the main tube 100 and on the secondary tubes 110 and 120, the internal surface portion 24 delimits a certain closed volume or reservoir 28, located between the external surface of the main tube 100 and the sleeve 10, and between the external surfaces of the ends of the secondary tubes 110 and 120 and the assembled semi-cylindrical portions 261 and 271 forming the two cylindrical shells 26 and 27. The internal surface portion 22 is in contact with the external surface of the main tube 100 and the secondary tubes 110 and 120, thus creating a barrier between the outside and the inside of this reservoir 28. When the sleeve 20 is in place on the main tube 100, the reservoir 28 is accessible from the outside through at least one opening 29. The reservoir 28 can also be filled from inside the main tube through a hole made in the thickness of the tube.However, access may be more difficult than from the outside in the case of a long main tube. The internal surface portion 22 protrudes relative to the internal surface portion 24 of the sleeve, resulting in an offset between the two surfaces 22 and 24, with a distance ranging from 0.1 mm to 1 mm. This design ensures sufficient thickness to allow the filler to flow and to achieve the required mechanical performance at the seal formed by the filler.

[0020] The assembly device comprises at least one projecting element 81 connected to the sleeve 20, which fits into at least one cavity provided on the external surface of the main tube 100. The projecting element 81 is located on the internal surface portion 24 of the sleeve so as to be situated within the recess 28. The cavity into which the projecting element 81 fits is not shown in the figures 1 and 2This cavity can pass through the tube wall but can also be machined into the thickness of the tube wall so as not to pass through. The projecting element 81 is in the form of a lug with a diameter approximately equal to 5 mm. Preferably, each cylindrical shell 26 and 27 comprises at least one projecting element 82 identical to the projecting element 81 located on the portion 24 of the inner wall of the shells that is not in contact with the outer wall of the secondary tubes 110 and 120. The projecting element 82 connected to each shell of the sleeve 20 is designed to fit into a cavity provided on the outer surface of each secondary tube 110 and 120 so as to mechanically lock the secondary tubes. Once the sleeve 20 is in place and tightened against the main tube using the assembly means, the connection of the sleeve 20 to the main tube 100 is secured and that with the secondary tubes 110 and 120 as well.In particular, at least one projecting element 81 prevents the translation and rotation of the sleeve 20 relative to the main tube 100 and at least one projecting element 82 prevents the rotation of each tube 110 and 120. In the assembled position on the main tube 100 shown in the figure. figure 4The two half-sleeves 201 and 202 of the sleeve 20 are mechanically connected to the main tube 100 by clamping via a bolted or riveted connection 73, which maintains the attachment areas 21 and 23 in tight contact with each other. Since the main body of the sleeve 20 is in the shape of a cylinder truncated at both ends, the contour of the sleeve bases is elliptical rather than circular, and the contact of the internal surface portion 22 with the main tube occurs over an oblique section of the tube. However, for practical reasons of terminology, and because the sleeve could have a cylindrical shape without departing from the scope of the invention, it is considered here to be a circumference. The internal surface portion 22 is in tight contact with the main tube over at least 90% of the circumference of the main tube 100, as can be seen in the figure. figure 4This has the advantage of distributing the clamping forces as evenly as possible around the tube to transmit the forces over the entire circumference of the main tube and the sleeve. The remaining 10% is considered to correspond to the location of the hinge and the attachment areas. Similarly, the internal surface portion 22 located in the semi-cylindrical sections of the two shells intended to enclose the ends of the secondary tubes 110 and 120, and in contact with them, is situated on the entire circumference of the secondary tubes. In this way, the clamping force is distributed evenly around the secondary tubes 110 and 120. Preferably, the filler is injected into the reservoir 28 through an orifice 29 provided in the wall of the sleeve 20 when the sleeve 20 is press-fitted onto the main tube 100.Preferably, a second opening connects the reservoir 28 to the outside and serves as a vent to allow air to escape during filling. The volume of injected filler is slightly greater than the volume of the reservoir 28 to allow visual verification of the actual filling as soon as the filler overflows through the vent. The filler is a polymer such as an epoxy resin, or a thermosetting or thermoplastic material, injectable or not, structured or unstructured. The polymer may be filled with mineral or metallic particles to improve its resistance to compressive stresses. The filler is intended to fill the entire volume of the reservoir 28 and fill the gaps between the protruding elements 81 and 82 and the cavity into which they are inserted. The filler conforms to the internal surface portion 24 of the sleeve and to the walls of the main tube 100 and secondary tubes 110, 120 to which it is applied.However, the filler does not prevent the disassembly and reuse of sleeve 20. The surface area and thickness of reservoir 28 are known; therefore, the quantity of filler required to completely fill reservoir 28 is known and can be quantified and predicted at the time of injection to ensure the necessary and sufficient amount is injected. Being able to control the quantity and filling of reservoir 18 has the advantage of guaranteeing a homogeneous and reproducible distribution of stresses within the filler.

[0021] THE figures 5, 6 And 7 represent a second embodiment of the assembly device according to the invention. According to this embodiment, the assembly device mainly comprises a sleeve 30 intended to be connected to one of the main tubes 100 of a truss beam and to at least one secondary tube, and preferably two secondary tubes which are not shown in the figures 5 and 6 The sleeve 30 is a single piece and comprises a main body in the shape of a cylinder or, preferably, in the shape of a cylinder truncated at both ends. The sleeve includes at least two attachment zones 11 and 13 situated in planes passing through the longitudinal axis of the sleeve. The attachment zones are intended to be rigidly joined together by means of fasteners that hold the sleeve 30, mounted coaxially on the main tube 100, tightly such that a portion of the inner surface 32 of the sleeve is in contact with the outer surface of the main tube 100. The sleeve also includes means for attaching to at least one secondary tube. As in the embodiment illustrated by the figures 1 and 2The means for connecting the secondary tubes are common to the assembly means for rigidly joining the attachment zones 11 and 13 against each other and are bolt-type means in fixing holes located on each attachment zone and at the end of each secondary tube 110 and 120. A rivet assembly can also be used. On the attachment zones 11 and 13, a boss 15 can be provided for each zone to prevent buckling of each zone.

[0022] The internal surface portion 32 of the sleeve 30 in contact with the external surface of the main tube 100 is peripheral; that is, it is located on the periphery of the sleeve and thus surrounds the internal surface portion 34 of the sleeve that is not in contact with the external surface of the main tube 100. When the sleeve 30 is in place on the main tube 100, this internal surface portion 34 delimits a certain closed volume or reservoir 38, located between the external surface of the main tube 100 and the sleeve 30. The internal surface portion 32 in contact with the external surface of the main tube thus forms a barrier between the outside and the inside of this reservoir 38. When the sleeve 30 is in place on the main tube 100, the reservoir 38 is accessible from the outside through at least one opening 39. The reservoir 38 can also be filled from the inside of the main tube through a hole made in the thickness of the tube.However, access may be more difficult than from the outside in the case of a long main tube. The internal surface portion 32 protrudes relative to the internal surface portion 34 of the sleeve, resulting in an offset between the two surfaces of between 0.1 mm and 1 mm. This has the advantage of ensuring sufficient thickness to allow the filler to flow and to achieve the required mechanical performance at the seal formed by the filler.

[0023] According to the figure 7The assembly device formed by the sleeve 30 comprises at least one projecting element 83 connected to the sleeve 30, which fits into at least one cavity 183 provided on the external surface of the main tube 100. The projecting element is located on the internal surface portion 34 of the sleeve so as to be situated within the recess 38. The projecting element 83 is located on the circumference of the inner wall of the sleeve, this circumference being circular or elliptical depending on whether it is considered in a straight or oblique section of the sleeve 30. Preferably, the projecting element 83 is located on the entire circumference of the sleeve in the form of a projecting ring as illustrated in the figure 5 However, the protruding element 83 is on at least 90% of the circumference of the sleeve 30 without going outside the scope of the invention. According to the figure 5In this embodiment, two projecting elements 83 are present and are located in the recess 38. The cavity into which the projecting element 83 is inserted is shown on the figures 6 And 7 , in the form of a non-through groove 183 located on the outer wall of the main tube 100 over its entire circumference.

[0024] Another projecting element can be provided, connected to the internal surface portion 34 of the sleeve 30 and located longitudinally along the sleeve and within the recess 38. This element, not shown in the figures, is designed to fit into a cavity 184 provided on the external surface of the main tube 100 in the form of a non-through groove located on the external wall of the main tube 100 parallel to its longitudinal axis. According to the figure 6The cavity 184 opens at each of its ends into a cavity 183. The sleeve 30 is threaded onto the main tube 100 so that the protruding element 83 coincides with the cavity 183 provided for this purpose on the main tube 100. Once the sleeve 30 is in place and tightened against the main tube by means of the assembly means, the connection of the sleeve 30 on the main tube is secured and that with the secondary tubes as well.

[0025] In particular, the salient element 83 prevents the translation of the sleeve 30 relative to the main tube 100 and the salient element located in the longitudinal axis of the sleeve prevents the rotation of the sleeve 30 relative to the main tube 100.

[0026] The sleeve 30 in its assembled position on the main tube 100 is not shown in the figures 5 and 6In this position, the sleeve 30 is mechanically connected to the main tube 100 by clamping via a bolted or riveted connection that maintains the attachment areas 11 and 13 in tight contact with each other. The inner surface portion 32 of the sleeve 30 is in tight contact with the main tube over at least 90% of its circumference, which is almost the entire circumference of the main tube 100. This has the advantage of distributing the clamping forces as evenly as possible around the tube, thus transmitting the forces over the entire circumference of both the main tube and the sleeve.

[0027] When the sleeve 30 is tightly fitted onto the main tube 100, a longitudinal slot in the sleeve's thickness may remain between the two attachment points 11 and 13. This slot acts as a vent to allow air to escape during the filling of the reservoir 38 through the orifice 39. The volume of injected filler is slightly greater than the volume of the reservoir 38 to allow visual verification of the actual filling as soon as the filler overflows from the vent. The filler is a polymer such as an epoxy resin, a thermosetting material, or a thermoplastic material, whether injectable or not, structured or not. The polymer may be filled with mineral or metallic particles to improve its resistance to compressive stresses. The filler is intended to fill the entire volume of the reservoir 38 and fill the gaps between the protruding element and the cavity into which it is inserted. As illustrated in the figure 7There is a radial gap between the protruding element 83 and the bottom of the cavity 183, the protruding element 83 not being in contact with the tube 100, and this radial gap is filled by the filler. The filler coincides with the internal surface portion 34 of the sleeve and with the wall of the tube to which it is applied. However, the filler does not prevent the sleeve 30 from being disassembled and reused. The surface area and thickness of the reservoir 38 are known; therefore, the quantity of filler required to completely fill the reservoir 38 is known and can be predicted at the time of injection to ensure the necessary and sufficient quantity is injected. Being able to control the quantity and filling of the reservoir 18 has the advantage of guaranteeing a homogeneous and reproducible distribution of stresses within the filler.Filling the reservoir 18 with the filling agent eliminates the gaps between the sleeve 30 and the main tube 100.

[0028] According to a third embodiment of the assembly device according to the invention shown in the figure 8 The protruding element is not an integral part of the sleeve, unlike protruding element 83, which may have resulted from a machining operation within the thickness of the sleeve wall. The sleeve is designated by reference 40 to avoid confusion with sleeve 30 of the... figure 5Apart from this difference, the sleeve 40 is identical to the sleeve 30. When the sleeve 40 is tightly fitted onto the main tube 100, the reservoir 38 is filled with a filler through the orifice 39. The filler fills the entire volume of the reservoir 38 and fills the cavities 183 and 184 located on the main tube. At the locations of the cavities 183, the filler, which is bonded to the sleeve and forms an integral part of the assembly device according to the invention, forms at least one protruding ring 85 on the internal surface portion 34 over at least 90% of the circumference of the sleeve. At the locations of the cavities 184, the filler, which is bonded to the sleeve and forms an integral part of the assembly device according to the invention, forms a ridge on the internal surface portion 34 of the sleeve in the longitudinal direction. The protruding element 85 fits into at least one cavity 183 provided on the external surface of the main tube 100.Indeed, the filler represented by hatching forms a layer of constant thickness in the reservoir 38 except at the location of the cavities where it forms an extra thickness to form the protruding ring 85. The cavities are dimensioned and placed on the tube 100 so that the internal surface part 34 of the sleeve 30, once in assembled position on the tube, covers and encompasses the cavities, so that the protruding element is located in the closed volume that constitutes the reservoir 38.

[0029] According to the second and third embodiments of the device according to the invention shown in the figures 5 to 8The sleeve 30 is a single piece, and not articulated as in the case of sleeve 20. However, the articulated version of sleeve 20 can be adapted for the second and third embodiments. In this case, sleeve 30, 40, 50, or 60 could consist of two identical and symmetrical parts or half-sleeves 201 and 202, joined together by a hinge 25 as described previously for sleeve 20, without departing from the scope of the invention.

[0030] Other methods for connecting the secondary tubes 110 and 120 to the sleeve are shown in the Figures 9 and 10 According to the figure 9, a sleeve 50 is mounted coaxially on the main tube 100. The sleeve 50 has at least one of the protruding elements 81, 83 or 85 described previously on the sleeves 10, 20, 30 and 40. The sleeve includes two attachment zones 51 and 53 located in planes passing through the longitudinal axis of the sleeve. The attachment zones are intended to be rigidly joined together by means of assembly which hold the sleeve tightly on the main tube 100 so that a portion of the inner surface of the sleeve is in contact with the outer surface of the main tube 100. The means of connecting the secondary tubes 110 and 120 to the sleeve 50 are common with the means of assembly for rigidly joining the attachment zones 51 and 53 against each other and are joined at a single assembly point by means of a bolted 75 or riveted connection placed in fixing holes located on each attachment zone and at the end of each secondary tube 110 and 120.An assembly method in the form of a clip system can also be used. In this way, the secondary tubes are connected to the main tube via a single connection point. This variant has the advantage of reducing the number of accessories required and the size of the sleeve, thereby optimizing the mass of the assembly device according to the invention.

[0031] According to the Figure 10A sleeve 60 is mounted coaxially on the main tube 100. The sleeve 60 has at least one of the projecting elements 81, 83, or 85 described previously for sleeves 10, 20, 30, and 40. The sleeve includes two attachment zones 21 and 23 located in planes passing through the longitudinal axis of the sleeve. The attachment zones are intended to be rigidly joined to each other by means of bolt-type fasteners 73 that hold the sleeve tightly against the main tube 100 so that a portion of the inner surface of the sleeve is in contact with the outer surface of the main tube 100. The sleeve 60 comprises a main body and two cylindrical shells 66 and 67 intended to enclose the ends of the secondary tubes 110 and 120 so as to mechanically lock the secondary tubes. In the case of a hinged-type sleeve such as that described with reference to figures 3 and 4, the sleeve has two identical and symmetrical parts connected by a hinge and the shells consist of two semi-cylindrical parts in each part.

[0032] Each secondary tube 110 and 120 has at its end a ring with a diameter larger than the diameter of the tube. Only the ring 113 of tube 110 is shown on the Figure 10 Each shell 66 and 67 has a housing, respectively 63 and 64, complementary to the ring 113. When the sleeve 60 is assembled around the tubes, the ring of each secondary tube is trapped in the housing of each of the shells 66 and 67.

[0033] The sleeves 50 and 60 of the variant embodiments include at least one protruding element in the form of a lug 81 or a protruding ring 83 or 85 such as those described previously with reference to the three embodiments.

[0034] Sleeves 10, 20, 30, 40, 50 and 60 of the different embodiments are made of aluminium or composite materials, the main tube 100 and the secondary tubes 110 and 120 composing the truss beams are made of composite materials.

[0035] According to a variant of all the embodiments described above, the filler is not injected but placed in the reservoir 18, 28 or 38 in the form of a film. In this case, the internal surface portion 12, 22 and 32 is projecting relative to the internal surface portion 14, 24 and 34 of the sleeve such that there is an offset between the two surfaces of between 80% and 98% of the thickness of the filler film.

[0036] Whether in the form of injected filling agent or in the form of a film, the assembly device according to the invention makes it possible to guarantee the filling by the filling agent of all the reserves 18, 28 and 38. In addition, the volume of injected filling agent is calibrated so as to fill the available volume with a very slight excess which will allow to visually check that the cavity is filled.

[0037] This optimal filling ensures the sealing of the assembly device and thus prevents corrosion. Indeed, the filling agent is in close contact with the inner wall of the sleeve (10, 20, 30, 40, 50, or 60) and with the outer wall of the main tube and, in the case of assembly devices with a sleeve equipped with shells to wrap the ends of the secondary tubes, with the outer walls of the secondary tubes.

[0038] The sleeves 10, 20, 30, 40, 50, and 60 of the assembly device according to the invention have the advantage, thanks in particular to the tight contact of the internal surface portions 12, 22, and 32 against the external surface of the main tube, of ensuring the mechanical connections between the tubes to form a truss beam structure and of transmitting significant forces through these connections. Consequently, in the event of a failure of the close contact of the filler on the walls of the sleeve and the main tube, the integrity of the truss beam is not compromised. The assembly device according to the invention ensures the mechanical connection of the tubes over a temperature range of -200°C to +250°C. Furthermore, the industrialization of assembling a truss beam is simplified thanks to the assembly device according to the invention without affecting the mass of the structure.

[0039] One advantage of the assembly device according to the invention is that it allows relative movement between the parts to obtain the desired assembly before fixing it. Indeed, before filling with the filling agent, the sleeves 10, 20, 30, 40, 50 and 60 are positioned on the main tube 100 with some play.

Claims

1. A device for assembling secondary tubes (110, 120) on a main tube (100) made of composite material comprising a sleeve (10, 20, 30, 40, 50, 60) mounted coaxially on said main tube and provided with two attachment zones (11, 13, 21, 23, 31, 33, 51, 53) located in planes passing through the longitudinal axis of said sleeve, said attachment zones being designed to be rigidly assembled together by means of assembly means (61, 71, 73, 75) which clamp said sleeve to said main tube so that a portion of the inner surface (12, 22, 32) of said sleeve is in contact with the outer surface of said main tube, the sleeve comprising means (26, 27, 66, 63, 67, 64, 82, 61, 71, 73, 75) for connecting to at least one secondary tube (110, 120), characterized in that said inner surface portion of said sleeve in contact with the outer surface of said main tube is peripheral and surrounds a portion of the inner surface (14, 24, 34) of said sleeve which is not in contact with the outer surface of said main tube so as to delimit a reserve (18, 28, 38) between the outer surface of said main tube and said filler-filled sleeve, the assembly device comprising at least one protruding element (81, 83, 85) connected to the sleeve which fits into at least one cavity provided on the outer surface of said main tube, the protruding element being located in the reserve (18, 28, 38).

2. The assembly device according to claim 1, wherein the protruding element is a lug (81) located on the inner surface portion (14, 24) of the sleeve (10, 20, 50, 60).

3. The assembly device according to claim 1, wherein the protruding element is a protruding ring (83, 85) on the inner surface portion (34) of the sleeve (30, 40, 50, 60) over at least 90% of the sleeve circumference, and the cavity provided on said main tube into which the protruding element fits is a non-through groove (183) located over the entire circumference of the outer wall of the main tube (100).

4. The assembly device according to claim 3, wherein the groove (183) extends onto a non-through longitudinal groove (184) located on the outer wall of the main tube (100).

5. The assembly device according to any of claims 1 to 4, wherein the filler is a polymer material injectable through an orifice (19, 29, 39) and the distance between the outer wall of the main tube (100) and the inner wall portion (14, 24, 34, 44) of the sleeve reserve (18, 28, 38) is between 0.1 mm and 1 mm.

6. The assembly device according to any of claims 1 to 4, wherein the filler is a polymeric material positioned on the inner wall portion (14, 24, 34) of the reserve (18, 28, 38) of the sleeve (10, 20, 30, 40, 50) in film form and the distance between the outer wall of said main tube and the inner wall portion (14, 24, 34) of the sleeve at a thickness of between 80% and 98% of the film thickness.

7. The assembly device according to any of claims 1 to 6, wherein assembly means for rigidly assembling together said attachment zones are bolted (61, 71, 73, 75) or riveted connection means or assembly means in the form of a clip system.

8. The assembly device according to claim 7, wherein the means for connecting the sleeve (10, 30, 40, 50) to at least one secondary tube (110, 120) are common with the assembly means for rigidly assembling the attachment zones (11, 13, 51, 53), the bolted (61, 71, 75) or riveted connection being placed in fixing holes located on the attachment zone (11, 13, 51, 53) and at the end of each secondary tube (110, 120).

9. The assembly device according to any of claims 1 to 8, wherein the means for connecting the sleeve (20, 60) to at least one secondary tube (110, 120) comprise two cylindrical shells (26, 27, 66, 67) designed to enclose the ends of the two secondary tubes (110, 120).

10. The assembly device according to claim 9, wherein each cylindrical shell (26, 27) comprises at least one protruding element (82) located on the inner wall portion (24) of the shells which is not in contact with the outer wall of the secondary tubes (110, 120), the protruding element (82) connected to each shell of the sleeve (20) is designed to be fitted into a cavity provided on the outer surface of each secondary tube (110, 120).

11. The assembly device according to claim 9, wherein each secondary tube (110, 120) comprises at its end a ring (113) with a diameter greater than the diameter of the tube and each shell (66, 67) comprises a housing (63, 64) respectively, complementary to the ring (113) so that when the sleeve (60) is assembled around the tubes, the ring of each secondary tube is trapped in the housing of each of the shells (66, 67).

12. The assembly device according to any of claims 1 to 11, wherein the sleeve (30, 40, 50, 60) consists of two identical and symmetrical portions or half-sleeves (201, 202), connected together by a hinge (25) so as to form an articulated sleeve.