MULTI-PART TUBE JOINT

Description

Technical field

[0001] The invention relates to a multi-part pipe joint for connecting pipe sections in pipelines, which is installed in particular in an aircraft. Furthermore, the invention relates to the use of the multi-part pipe joint in aircraft. State of the art

[0002] DE 847 538 relates to a single- or multi-joint pipe connection for thin-walled sheet metal pipes with sealing against internal overpressure. According to this solution, a single- or multi-joint pipe connection is proposed for thin-walled sheet metal pipes with sealing against internal overpressure. In this solution, the pipe ends are designed as spherical shells. Flexible, elastic, and temperature-resistant sealing elements are inserted between the two overlapping spherical surfaces. These sealing elements are pressed into place by the engagement of the outer spherical surfaces or by adjustable pressure elements, creating a sealing and sliding seal. The sealing elements are designed as rings mounted on pressed, forged, or cast bodies whose inner diameter matches the inner pipe, while the outer surface is convex according to the inner diameter of the outer sphere.

[0003] DE 22 62 775 C3 relates to an articulated pipe connection. This connection serves to link a riser pipe to a conveying pipe running at an angle to it. The conveying pipe is a suction conveying device with a segmented pipe, which is connected to the conveying pipe and to the riser pipe mounted on a bracket pivotable about an axis of rotation. The bracket is part of a pivotable frame with joints. The pivot bearings connecting the axes of the segmented pipe sections run parallel to the axes for rods arranged on the support.

[0004] DE 10 2006 029 705 A1 relates to a pipe connection and a pipe connection system with such pipe connections. The pipe connection serves to connect a first pipe to a second pipe, wherein a connecting end of the first pipe and a connecting end of the second pipe form a pivot joint. An axis of rotation of the pivot joint and a pipe axis of the first and second pipes form an angle α. The first pipe is rotatable relative to the second pipe from a first angle to a second angle.

[0005] DE 931 988 C, KR 2014 0014491 A and WO 2015 / 039081 A1 refer to a multi-part pipe joint for connecting pipe sections with pivot points in an axial offset to each other.

[0006] Pipe joints used in aircraft piping systems are typically designed as universal joints, comprising two axes that intersect at a 90° angle for angular movement. This ensures that the pipe axes always meet at the same point of intersection, regardless of the direction of angular movement. When the pipeline is under internal pressure, tensile forces arise that must be transmitted through the universal joint. Due to the intersecting axes, the force flow lines, along which these tensile forces travel, inevitably involve several 90° deflections. This exposes the components of the universal joint to relatively high mechanical stress, necessitating a complex and heavy design. This, in turn, contradicts the desired lightweight construction, particularly in aerospace applications. Description of the invention

[0007] The invention is based on the objective of designing a pipe joint of a piping system, particularly in lightweight construction, and constructing it in such a way that it is sealed against internal pressure prevailing in the piping system in all possible deflection positions of the pipe joint and, on the other hand, force flow lines that occur during tensile loading of the pipe joint have a mechanically optimized course.

[0008] According to the invention, a multi-part tubular joint is proposed, which has a central section on which adjustable joint elements are mounted relative to the central section. These joint elements are rotationally fixed to the central section at pivot points, wherein the pivot points of the joint elements on the central section simultaneously serve as pivot points for transmission elements that extend axially along an inner wall of the central section. By axially offsetting both tube axes, i.e., the central section and the joint elements relative to each other, the force deflection within the central section can be reduced from 90° to 45°.

[0009] This reduces the torsional stress on the pipe cross-section in the central section, thereby reducing material usage and consequently weight. Because the opposing pivot points forming the joint axes are axially offset from each other, less pronounced load flow patterns can be achieved under internal pipe pressure, resulting in lower material stress.

[0010] Following the solution proposed according to the invention, the multi-part pipe joint is designed such that the pivot points for the transmission elements are arranged at 45° intervals with respect to the circumference of the central piece. Alternatively, it is possible to design the pivot points for the transmission elements at a different interval than the aforementioned 45° interval with respect to the circumference of the central piece.

[0011] Further developing the solution proposed according to the invention, the multi-part pipe joint is designed such that a pair of transmission elements, arranged offset by 180° from each other, are connected to the central piece and the first joint part in a rotationally fixed manner at the two first pivot points. Furthermore, another pair of transmission elements, also arranged offset by 180° from each other, is connected to the central piece and the second joint part in a rotationally fixed manner at the two second pivot points. Further developing the solution proposed according to the invention, the multi-part pipe joint is designed such that several units can be combined in series to form a flexible, freely movable assembly that behaves mechanically similarly to a hose and transfers this property to an originally rigid pipe system.

[0012] In an advantageous embodiment of the transmission elements according to the invention, these are essentially designed in the form of tabs and are pivotable relative to the inner wall of the central piece.

[0013] Advantageously, the multi-part pipe joint is designed such that the joint parts each have a recess on their end faces facing away from the pipe ends. The recesses serve to prevent angular misalignment during relative movement of the adjustable joint parts with respect to the central piece.

[0014] Advantageously, these recesses are designed as rounded shapes, which are particularly easy to manufacture.

[0015] The multi-part pipe joint proposed according to the invention is designed such that the central part of the multi-part pipe joint has a circumferential groove formed centrally in the material to form a pipe wall.

[0016] Depending on the angle between the plane spanned by the pipe axes and the planes in which the joint axes lie, the bellows can be deformed at two axial positions at 90° angles with different deflections. The bead supports the bellows during dynamically changing angular positions of the pipe axes, reducing wear via its large radius and thus preventing wear-inducing contact between the bellows and the protruding elements of the joint axes. The bead therefore assumes a guiding function. Furthermore, the cross-section of the center section is twisted due to the internal pipe pressure, which subjects the multi-part pipe joint to tensile forces. The distance between the joint axes reduces these tensile forces, as the force flow in the cross-section of the center section no longer needs to be deflected by 90°, but only by 45°. The bead, in conjunction with the inner tabs, resists this torsion.The transmission elements are formed as a closed cross-section at the four positions of load application via the joint axes. Therefore, the groove also has a load-bearing function.

[0017] Further developing the solution proposed according to the invention, the joint components of the multi-part pipe joint are designed such that their end faces facing the pipe ends each have an increase in diameter, which serves as mounting surfaces for receiving a bellows covering the multi-part pipe joint. The function of the bellows is to provide a seal against internal pressure. Due to its corrugated design, the bellows is pressure-resistant, yet flexible enough to follow any angle of the multi-part pipe joint.

[0018] In the multi-part tubular joint proposed according to the invention, the first joint part is pivotable relative to the central section about the first pivot points, which are arranged at a 180° offset from each other. Furthermore, the second joint part is pivotable relative to the central section about the second pivot points, which are also arranged at a 180° offset from each other. In a preferred embodiment of the multi-part tubular joint, the minimum axial gap between the end face of the first tube end and an opposite end face of the central section is 3 mm, preferably 1 mm. The minimum radial gap between the first joint part and an outer wall of the central section is less than 1.5 mm, preferably a few tenths of a millimeter, and particularly preferably 0.2 mm.

[0019] In an advantageous further development of the multi-part pipe joint proposed according to the invention, a ring is arranged in the area of ​​the pivot points of the transmission element between an outer wall of the central piece and an inner wall of the first and second joint parts, which are movable relative to the central piece. This ring—or alternatively, a disc—ensures a distance between the moving pipe ends and the central piece, which is what enables these components to move relative to each other. Without the minimum distance defined by the ring or disc, these components would touch and, when angular, rub against each other, or deformation would occur. If the disc or ring is made of a flexible material such as PTFE, it is inserted during assembly and adapts itself to the curvature of the pipe diameter, thus reducing wear.

[0020] If the ring or disc is made of metallic material, it is adapted to the curvature of the pipe ends and bonded to them before assembly, for example by welding. This additionally reduces bearing stress and surface pressure in the area of ​​the joint axes, acting as a reinforcing element. These two construction methods can also be combined for the ring or disc.

[0021] The invention further relates to the use of the multi-part pipe joint in an aircraft for starting at least one engine and for heating or ventilating the passenger cabin. In this context, such an aircraft configuration is understood to be a bleed air system, which conveys compressed and therefore warmer air from the turbine compressor of jet engines on the wings to the aircraft's air conditioning system in the fuselage. It is also possible to use the bleed air system to route hot exhaust gases from an auxiliary power unit, such as one located in the tail of a passenger aircraft, to the aircraft's engines and start them sequentially. The bleed air system thus connects the propulsion turbines in the wings with the auxiliary power unit in the aircraft's tail and the air conditioning system in the fuselage.The aircraft structure at the fuselage-wing junction is subject to strong elastic deformations, which the normally installed tubes in the bleed-air system cannot withstand. Therefore, the multi-part tube joints proposed according to the invention are used particularly at these locations. Advantages of the invention

[0022] By axially offsetting the two pipe axes around two pivot points, the force deflection within the center section can be reduced from 90° to 45°. This reduces the torsional stress on the pipe cross-section of the center section, thereby also reducing its weight during design. In terms of weight savings for aircraft, this represents a crucial difference compared to prior art solutions and offers an advantage over previous designs.

[0023] If, in the multi-part pipe joint proposed according to the invention, both pipe ends are deflected relative to the central section by, for example, 7°, this results in a maximum axial offset of the pipe ends of 7.3 mm at an angle of 45° between the plane of the two pipe axes, which are at a maximum angle of 10° to each other, and the joint axes. The solution proposed according to the invention can, in the case of axial offset, be influenced by a predetermined rotational position in the pipe system, corresponding to the expected deflection planes of the multi-part pipe joint during subsequent operation. The axial offset of the two pipe axes can reduce the force deflection within the central section from 90° to 45°.This reduces the torsional stress on the annular tube cross-section in the central section, thereby reducing the amount of material used and thus also the weight of the multi-part tube joint proposed according to the invention. This represents an advantageous difference compared to previously used, heavier designs, particularly in aerospace applications. For example, if the two joint components articulated to the central section are provided with recesses at their ends facing the central section, preferably rounded, a greater deflection of the two joint components articulated to the central section can be achieved. This results in greater freedom of installation for the tube joint proposed according to the invention, allowing for adaptation to confined installation spaces.Furthermore, if the central section is provided with a circumferential groove formed in its pipe wall, a bellows surrounding the multi-part pipe joint, in particular a bellows, can be flexibly deformed during deflection movements of the components of the multi-part pipe joint. The circumferential groove supports the bellows during dynamically changing angular positions of the pipe axes, reducing wear via its relatively large groove radius and thus minimizing wear-inducing contact between the bellows and protruding elements of the joint axes at the pivot points. This groove therefore advantageously serves a guiding function. If the cross-section of the central section is subjected to torsional movement, for example by the internal pipe pressure, the multi-part pipe joint is subjected to tensile forces.The distance between the joint axes significantly reduces this, as the force flow in the cross-section of the central piece no longer needs to be deflected by 90°, but only by 45°. The multi-part tubular joint proposed according to the invention is further advantageously characterized by the fact that rings made of metal, or alternatively a disc made of PTFE, can be installed as a spacer ring to reduce friction and reinforce the pivot points. This creates a gap between the outer wall of the central piece and the inner wall of the adjustable joint parts, thus preventing friction-inducing movement, while still allowing movement.

[0024] The spacing between the joint axes proposed according to the invention offers the further advantage that the associated axial expansion of each universal joint, which combines a few pipe joints directly one behind the other into a system, creates a flexible, freely movable assembly that behaves mechanically similarly to a hose. Its flexible properties are transferred to a pipe system that was originally designed to be rigid. However, to achieve the same axial length with the multi-part pipe joint proposed according to the invention as with universal joints of the previously conventional design, fewer joints are required, and each of these joints is also lighter than universal joints of the previously conventional design. Both of these factors lead to a reduction in system weight when using the design proposed according to the invention compared to universal joints of the previously conventional design.

[0025] The maximum angular position of the tube axes relative to each other can be increased by the solution proposed according to the invention, since a longer bellows is more flexible and exhibits better fatigue strength properties. The number of cycles to be achieved at maximum deflection angle is specified for each system in aerospace applications. Due to the larger deflection angle, the possible number of cycles would decrease. However, the greater flexibility of a longer bellows with more corrugations, and thus a lower stress per corrugation at maximum deflection of the tube axes relative to each other, would compensate for the reduction in the possible number of cycles, and the values ​​specified for each system in aerospace applications would be achieved and exceeded.

[0026] The solution proposed according to the invention allows for an overall reduction in weight. An axial offset of the pivot points forming the joint axes results in less pronounced deflection of the load flow patterns in the gimbal ring when subjected to internal pipe pressure, and consequently, a significantly reduced material stress.

[0027] A further advantage of the solution proposed according to the invention is that, due to the extended design, the axially offset joint axes formed from the pivot points allow for a higher number of load cycles of the longer bellows while simultaneously enabling a larger maximum deflection angle of the tube axes relative to each other.

[0028] The solution proposed according to the invention further has the advantage that several multi-part pipe joints of the design proposed according to the invention can be coupled directly one behind the other, resulting in a weight-reduced pipe system with a hose-like mobility, compared to the rather rigid pipe systems of previous designs which only allow small deflection angles. Brief description of the drawing

[0029] The invention is described in more detail below with reference to the drawing. It shows: Figure 1 shows a perspective view of the multi-part pipe joint proposed according to the invention in an extended embodiment; Figure 2 shows a longitudinal section through the multi-part pipe joint proposed according to the invention in an extended position as shown in Figure 1. Figure 1Figure 3 shows the multi-part pipe joint proposed according to the invention in a first deflected position, Figure 4 shows the multi-part pipe joint proposed according to the invention in a second embodiment in a second position, Figure 5 shows a longitudinal section through the multi-part pipe joint in the second deflected position according to the invention. Figure 4 Figure 6 is a detailed drawing of a pivotable joint part with pivot points offset by 45° to each other, Figure 6.1 is a perspective view of a bottle-shaped transmission element, and Figure 6.2 is an assembly drawing of the pivotable joint part with transmission elements designed as tabs mounted on it. Design variants

[0030] Figure 1 Figure 1 shows the multi-part pipe joint 10 according to the invention in a perspective view in an extended position.

[0031] In perspective view according to Figure 1The multi-part pipe joint 10 shown comprises a central section 16. A first joint part 18 and a second joint part 20 are movably mounted on the central section 16. The first joint part 18 terminates in a first pipe end 12, while the second joint part 20 terminates in the second pipe end 14. The first joint part 18 is movably attached to the central section 16 at first pivot points 22, which form a joint axis. A further first pivot point 22 is located in the Figure 1 The first pivot point 22 shown is offset by 180° opposite and is located in the Figure 1 not shown.

[0032] The second joint part 20, which terminates in the second tube end 14, is articulated at the second pivot point 24 on the middle section 16, which forms another joint axis. The second pivot point 24, which is located in Figure 1 As shown, there is a [something] in Figure 1 not shown, a further second pivot point 24 opposite this one, offset by 180°.

[0033] According to the perspective view Figure 1 It can be seen that an offset 26 is formed between the first pivot point 22 and the second pivot point 24, which in this embodiment is essentially 45°. Instead of the one in Figure 1 Instead of the offset 26 shown, which is 45°, a different angle can also be chosen as the offset angle 28.

[0034] In the center of the middle section 16, a circumferentially formed groove 30 is located in its pipe wall. Reference numeral 32 designates the pipe cross-section, which is bounded by an inner wall 34 of the middle section 16, the first joint part 18 and the second joint part 20.

[0035] The pivotable joint parts 18, 20, arranged on both sides of the circumferential groove 30 formed centrally in the wall of the middle section 16, each have a first recess 36 and a second recess 38 on their side facing the circumferential groove 30. For manufacturing advantages, the first recess 36 and the second recess 38 are shaped as radii 40.

[0036] Figure 2 shows a longitudinal section through the in Figure 1 The multi-part pipe joint 10, as proposed in the invention, is shown in its extended position.

[0037] Figure 2It can be seen that the inner wall 34 has tab-shaped transmission elements 42. These are arranged at first pivot points 22 and second pivot points 24 on the inside of the inner wall 34 of the center section 16. The tab-shaped transmission elements 42 are pivotally mounted on cams 44, the cams 44 being part of the first pivot points 22 and the second pivot points 24, respectively. The first pivot points 22 and the second pivot points 24 are, as already described in connection with Figure 1 mentioned, offset by an angle of 28, for example 45° to each other. Figure 2Figure 1 further shows that the multi-part pipe joint 10 is enclosed by a bellows 56, which is shown here in a sectional view. The bellows 56 has shoulders at each of its ends, which are formed by a diameter increase 54. The diameter increase 54 refers to the distance between the outer wall 48 of a circumference 50 and the inner side of the bellows 56, which is preferably designed as a folded bellows. In the middle, the bellows 56 is supported by the circumferential groove 30 formed centrally in the wall of the middle section 16. In the sectional view according to Figure 1. Figure 2It is shown that the transmission element 42 extends in its longitudinal extent 52 parallel to the inner wall 34 of the central piece 16. The longitudinal extent 52 of the transmission elements 42 corresponds to the length of the central piece 16. The inner surfaces of the first joint part 18 and the second joint part 20 adjoin its edges, before the first pipe ends 12 and the second pipe ends 14, respectively, connect to these.

[0038] The circumferential groove 30 formed in the wall of the central section 16 supports the bellows 56 during dynamically changing angular positions of the joint parts 18, 20, thus reducing wear by means of its large radius and preventing wear-inducing contact of the bellows 56 with protruding elements of the joint axis, in particular a disc 46 on the outside of the first and second joint parts 18, 20. The circumferential groove 30 therefore has a guiding function. Furthermore, it should be noted that the pipe cross-section 32 of the central section 16 is twisted due to the internal pipe pressure prevailing therein, so that the multi-part pipe joint 10 is subjected to tensile forces. The distance between the joint axes formed by the first pivot points 22 and the two second pivot points 24 significantly reduces the tensile forces, as the force flow in the cross-section of the middle piece 16 no longer needs to be deflected by 90°, but only by 45°.The circumferential groove 30, in conjunction with the inner tabs (i.e., the transmission elements 42), thus forms a closed cross-section at the four load application points, i.e., at the two first pivot points 22 and the two second pivot points 24 via the joint axes, counteracts the torsional stress. The circumferential groove 30 therefore assumes a load-bearing function.

[0039] The in Figure 2 The offset angle 28 of the offset 26 shown is 45°. This offset 26 is shown only as an example. Instead of the one shown in Figure 2 In addition to the offset shown (26) of 45°, other angles are also possible. Furthermore, according to the sectional view... Figure 2It can be seen that a ring 60 is mounted on the cams 44 – for example, at the two opposing second pivot points 24 – next to the disc 46. The ring 60 ensures a distance between the moving joint parts 18, 20 and the stationary center piece 16, and this distance is what makes the movement of these components possible in the first place. Without the ring 60 and the minimum distance it defines, the pivotable joint parts 18, 20 would touch and rub or even deform when angular. The ring 60 can also be made of a flexible material such as PTFE, inserted during assembly, and thus adapts itself to the curvature of the pipe diameter and serves to inhibit wear.If, on the other hand, the ring 60 is made of metal, it is adapted to the curvature of the pivotable joint parts 18, 20 and welded before assembly, thus reducing the surface pressure in the area of ​​the joint axes of the first pivot points 22 or the second pivot points 24, which are offset from each other by 180°, as an additional reinforcing element against the bearing of the hole.

[0040] According to the perspective representation Figure 3 A first deflection situation of the multi-part pipe joint 10 can be seen.

[0041] Figure 3 It can be seen that in this perspective view, the central axis 62 of the first joint part 18 has an axial offset 66 relative to the central axis 64 of the second joint part 20. The axial offset 66 is shown in the diagram. Figure 3approximately 7 mm, wherein the two joint parts 18, 20 are pivoted by 7° relative to the central piece 16, at an angle of 45° each between the plane of the two central axes 62 and 64 respectively, which are at a maximum angle 70 of 10° to each other, and the joint axes defined by the two first pivot points 22 and the two second pivot points 24. In the illustration according to Figure 4 This axis offset 66 is reduced to 0 mm as soon as the plane of the pipe axes coincides with one of the pivot axes, i.e., either the axis passing through the two first pivot points 22 or through the two second pivot points 24. (Representation in Figure 4 )

[0042] The axis offset 66 can be influenced by a predetermined rotational position in the pipe system according to the expected deflection planes of the multi-part pipe joint 10 under operating conditions. If this rotational position, i.e., the installation position, is not deliberately predetermined, the illustration describes Figure 3 the maximum possible axis offset 66 of the two pipe ends 12, 14 of the two joint parts 18, 20. The multi-part pipe joint 10 is to be designed to compensate for the maximum possible axis offset 66.

[0043] The axis offset 66 between the central axis 62 and the central axis 64 is shown in the illustration according to Figure 3 7.3 mm. The perspective view according to Figure 3Figure 1 also shows that the visible first and second pivot points 22, 24 are arranged at an offset angle 28, which has an offset of 45°. The pivot points opposite the two pivot points 22, 24 shown are offset by 180° from the first and second pivot points 22, 24 shown and are therefore not shown.

[0044] While the first joint part 18 can be moved about the two first pivot points 22 which are arranged offset from each other by 180°, as in Figure 3 As shown, the second joint part 20 moves about the two second pivot points 24, which are shown in the illustration according to Figure 3 They are 180° opposite each other. This means that the respective planes of movement of the two joint parts 18 and 20 are oriented offset from each other by 45°. Instead of an offset value of 45° - as in Figure 3As shown, another offset 26 could also be selected, for example 30°, 40°, 50° or even 60°. In all cases, the multi-part pipe joint 10 proposed according to the invention results in a significant reduction of the mechanical loads on the components of the multi-part pipe joint 10.

[0045] For the sake of completeness, it should be mentioned that in the perspective view according to Figure 3 , which represents the multi-part pipe joint 10 in a first deflection position, the tabs representing the transmission elements 42 extend parallel to the inner wall 34 of the central section 16 of the multi-part pipe joint 10. The transmission elements 42 are attached via the cams 44 at each of the first pivot points 22 or at each of the second pivot points 24 and are arranged to pivot relative to the inner wall 34.

[0046] Figure 4 shows a second deflection position of the multi-part pipe joint 10.

[0047] From the representation according to Figure 4 It is evident that in the second deflection position of the components of the multi-part pipe joint 10 shown there, an angle of 170° is enclosed between the central axis 62 of the first joint part 18 and the central axis 64 of the second joint part 20, compare reference numeral 68. The distance 72 between the central axes 62 and 64 is 0 mm, and the angle 70 is 10°. Analogous to the representation according to Figure 3 , which shows the first deflection position of the components of the multi-part pipe joint 10, is also shown in the illustration according to Figure 4 For reasons of clarity, bellows 56 has been omitted.

[0048] According to the representation Figure 5 A further section through the multi-part pipe joint 10 proposed according to the invention can be seen, the deflection position of which is shown according to Figure 5 identical to the one in Figure 4 is.

[0049] Figure 5shows that the central piece 16 has the circumferential groove 30 in its lateral surface, which includes an inner wall 34. In the sectional view according to Figure 5 The second joint part 20 is received at the two second pivot points 24 shown, which are offset from each other by 180° and are in a straight position with respect to the central axis 82 of the central part 16, i.e., not angled. Figure 5 As shown, cams 44 are formed on the lug-shaped transmission elements 42 at the two opposing second pivot points 24. A ring 60 for friction reduction is incorporated into the cams 44, and a disk 46 is located on the outside of each cam 44. The lug-shaped transmission elements 42 extend along the longitudinal dimension 52.

[0050] In contrast to the non-displaced position of the second joint part 20 with respect to the center piece 16, the first joint part 18 is in an angled position with respect to the center piece 16. This is evident from an angle that denotes a 10° offset 74 between the central axis 82 of the center piece 16 and the central axis 62 of the first joint part 18. The in Figure 5 The offset shown in section 74 is 10°. From the section view according to Figure 5 The angled position of the first joint part 18 in relation to the middle piece 16, as shown, results in a gap width of 1 mm, compare position 76, which is in the Figure 5The first joint part 18 is positioned in the deflected position shown between the two opposing end faces of the central piece 16 on the one hand, and the deflected position of the first joint part 18 on the other. Furthermore, a gap width 2, on the order of a few tenths of a millimeter, preferably 0.2 mm (see position 78), is established between the outer surface of the first joint part 18 and the outer wall 48 of the central piece 16. The Figure 5 The gap widths 1 and 2 shown, compare positions 76 and 78, occur when the first joint part 18 is deflected in relation to the stationary, stationary, center piece 16, especially with a maximum permissible angle compensation.

[0051] When the pipe axes of the two joint parts 18, 20 are deflected at an angle to each other, they define a plane. The joint axes formed by the opposing pivot points 22, 24, which are rotated 90° relative to each other, have an angle of rotation with respect to this plane. This results in two extreme rotation positions of 45° / 45° and 0° / 90° of the two joint axes relative to the plane of the pipe axis and every angle in between. At a rotation of 0° / 90°, there is an axial offset of 0.0 mm between the pipe axes at a maximum angle of 70° of 10°. At the extreme position of 45° / 45°, there is an axial offset of 7.3 mm between the pipe axes at a maximum angle of 70° of 10°.

[0052] The Figures 6, 6.1 and 6.2 The figures show the manufacturing and assembly steps of the central part 16 of the multi-part pipe joint 10 proposed according to the invention.

[0053] Figure 6 Figure 16 shows the central section 16, on the circumference of which 50 opposite bores 80 are formed, which have receptacles, for example, for the cams 44 of the lug-shaped transmission elements 42. The bores 80 with the cams 44 of the lug-shaped transmission elements 42 received therein represent the two first pivot points 22, offset from each other by 180°. Beyond the circumferential groove 30 running centrally in the central section 16, there are similarly offsets 26, which can be implemented at an offset angle 28 of, for example, 45°. Alternatives exist such that other offset angles 28 can be selected, for example, 30°, 40°, 50°, or 60°, in order to optimize the force flow lines. The bores 80 are in the Figure 6 The scheme shown is incorporated into the outer wall 48 of the tubular middle section 16. Figure 6.1The perspective view shows that in its installed position, the transmission element 42 nests against the inner wall 34 of the central piece 16. This includes at one end the cams 44, which are fitted into the bore 80 and secured by the disc 46.

[0054] The Figure 6.2 shows the transmission element 42, whose cams 44 are pressed into the bores 80 of the center piece 16. Figure 6.2 corresponds to the representation in Figure 6 , whereby the individual bores 80 for receiving the cams 44 of the lug-shaped transmission elements 42 are offset relative to each other and by the offset 26 at an offset angle 28. A pivot axis is formed by the two opposing first pivot points 22; a further pivot axis is formed by the two opposing second pivot points 24. Analogous to the representation according to Figure 6The central section 16 and the circumferential groove 30, which serves as support for the in, run centrally in the outer wall 48. Figure 2 The bellows shown in section 56 serve as a guide.

[0055] The invention is not limited to the embodiments described here and the aspects highlighted therein. Rather, within the scope specified by the claims, a multitude of modifications are possible that fall within the bounds of what is considered skilled in the art. Reference symbol list

[0056] 10 Multi-part pipe joint 12 First pipe end 14 Second pipe end 16 Center piece 18 First joint part 20 Second joint part 22 First pivot point 24 Second pivot point 25 Axial offset 26 Offset (45°) 28 Offset angle 30 Circumferential bead 32 Pipe cross-section 34 Inner wall 36 First recess 38 Second recess 40 Curve 42 Transmission element 44 Cam 46 Washer 48 Outer wall 50 Circumference 52 Longitudinal extent of transmission element 54 Diameter increase 56 Bellows 60 Ring 62 Center axis of first joint part 64 Center axis of second joint part 66 Offset of center axes 68 170° angle 70 10° angle 72 0-distance 74 10° offset 76 Gap width 1 (1.0 mm) 78 Gap width 2 (0.2 mm) 80 Bore for cam 82 Center axis center piece

Claims

1. Multipart pipe joint (10) comprising: - a centre piece (16), - a first and a second joint parts (18, 20) which are received on the centre piece (16), the joint parts (18, 20) being adjustable relative to the centre piece and which are rotationally fixedly connected to the centre piece (16) at articulation points (22, 24), - transmission elements (42), and - a bellows (56) which surrounds the centre piece (16), wherein the articulation points (22, 24) of the joint parts (18, 20) on the centre piece (16) simultaneously constitute articulation points (22, 24) for transmission elements (42) which extend axially along an inner wall (34) of the centre piece (16), the articulation points (22, 24) forming articulation axes being arranged in an axial offset (25) relative to one another, characterized in that the centre piece (16) has a circumferential crease (30) formed centrally in its pipe wall, which performs a wear-reducing guide function with respect to a bellows (56) and a load-bearing function with respect to torsion of the centre piece (16).

2. Multipart pipe joint (10) according to claim 1, characterised in that articulation points (22, 24) for the transmission elements (42) are arranged offset from one another in an offset (26) by an offset angle (28) with respect to a circumference (50) of the centre piece (16).

3. Multipart pipe joint (10) according to claim 2, characterised in that in each case a pair of transmission elements (42) offset by 180° relative to one another are rotationally fixedly connected to the centre piece (16) and the first joint part (18) at first articulation points (22).

4. Multipart pipe joint (10) according to claim 2, characterised in that in each case a pair of transmission elements (42) arranged offset by 180° relative to one another are rotationally fixedly connected to the centre piece (16) and the second joint part (20) at second articulation points (24).

5. Multipart pipe joint (10) according to claim 2, characterised in that the transmission elements (42) are substantially tab-shaped and pivotable on the inner wall (34) of the centre piece (16).

6. Multipart pipe joint (10) according to claim 1, characterised in that the joint parts (18, 20) each have a recess (36, 38) on their end faces facing away from the pipe ends (12, 14).

7. Multipart pipe joint (10) according to claim 6, characterised in that the recesses (36, 38) are each designed as a rounded portion (40).

8. Multipart pipe joint (10) according to claim 1, characterised in that the joint parts (18, 20) each have a diameter increase (54) on their end faces facing the pipe ends (12, 14), which respectively constitute mounting surfaces for receiving a bellows (56) covering the multipart pipe joint (10).

9. Multipart pipe joint (10) according to claim 3, characterised in that the first joint part (18) is pivotable with respect to the centre piece (16) and the first articulation points (22) arranged at an offset of 180° to one another.

10. Multipart pipe joint (10) according to claim 4, characterised in that the second joint part (20) is pivotable with respect to the centre piece (16) about the second articulation points (24) arranged in a 180° offset.

11. Multipart pipe joint (10) according to claim 1, characterised in that, with maximum permissible angular compensation, a minimum gap width 1 (76) in the axial direction between the end face of the first pipe end (12) and an end face of the centre piece (16) opposite thereto is 3 mm, preferably 1 mm.

12. Multipart pipe joint (10) according to claim 1, characterised in that, with maximum permissible angular compensation, a minimum gap width 2 (78) in the radial direction between the first joint part (18) and an outer wall (48) of the centre piece (16) is less than 1.5 mm, preferably a few tenths of a millimetre, most preferably 0.2 mm.

13. Multipart pipe joint (10) according to claim 1, characterised in that in the region of the articulation points (22, 24) of the transmission element (42) between an outer wall (48) of the centre piece (16) and an inner wall (34) of the first and second joint parts (18, 20) there is arranged a ring (60) which on the one hand brings about a spacing between the centre piece (16) and the joint parts (18, 20) and on the other hand serves as a reinforcing element with respect to surface pressures in the region of the articulation points (22, 24).

14. Use of the multipart pipe joint (10) according to one of the preceding claims in an air supply system for aircraft for starting the engines and / or for supplying the passenger cabin.