ELECTRICAL REFERENCE POTENTIAL ARRANGEMENT AND MOUNTING ARRANGEMENT FOR A PRINTED CIRCUIT

Description

TECHNICAL FIELD

[0001] The invention relates to the field of electrical connectors used in particular in aeronautics for aircraft avionics bays.

[0002] Avionics bays are electrical cabinets installed in aircraft to house electrical and electronic equipment, such as computers and other instruments, as well as the electrical wiring connecting this equipment. These avionics bays are generally quite large and contain numerous closely spaced electronic and electrical components, along with a large number of cables. An avionics bay typically includes a rack system that allows for the insertion and removal of equipment, providing mechanical support and electrical connections. These rack systems ensure a high level of safety in the management of electrical equipment, both during normal operation and during maintenance. PREVIOUS ART

[0003] Aircraft avionics bays typically include shelves to support electrical or electronic equipment.

[0004] Each electrical or electronic device needs to be connected to the electrical reference potential by being connected to conductive ground parts of the avionics bay.

[0005] The assembly of electrical and electronic circuits on an electrically conductive structure generally involves mechanically securing the circuit using a screw, washer, spacer, and nut. Furthermore, the electrical connection to the reference potential is typically achieved via a wire connection equipped with two terminals. Such assemblies are illustrated in patents CN102781151B, US2010 / 259907, and US5381314A.

[0006] This type of assembly is not compatible with an assembly that will undergo deformation during use. Any deformation will cause internal stresses within the circuit being held in place.

[0007] This type of assembly also uses many small components, which is unfavorable for maintenance operations.

[0008] The electrical connection to the reference potential also requires anti-corrosion protection such as a varnish, to protect the electrical contact surface against aggressions induced in particular by the environment of an aircraft. DESCRIPTION OF THE INVENTION

[0009] The invention aims to improve prior art electrical assemblies.

[0010] To this end, the invention relates to a fixing and electrical reference potential setting assembly for an electrical circuit, this assembly comprising an electrically conductive flexible clip which includes: a conductive clamp for clamping electrical circuits; an electrical contact heel; a fixing suitable for clamping the electrical contact heel against an electrical contact surface. The assembly further comprises an electrically conductive tab having a mounting tab on a structure and presenting an electrical contact surface, the flexible clip being fixed to the tab so that the electrical contact heel is positioned against the electrical contact surface.

[0011] The assembly according to the invention combines the two functions of mechanical support and electrical continuity into a single sub-assembly secured to the electrical circuit by means of the clamp. Several assemblies can be used to fix an electrical circuit to a support such as an avionics bay shelf, depending on the size of the circuit. This assembly allows the electrical circuit a certain degree of movement relative to, for example, temperature changes, mechanical movements, or vibrations, without inducing stress within the circuit.

[0012] Intervention on an aircraft electrical system by removing and replacing the assembly is simplified and made more reliable.

[0013] No chemical compound, such as varnish or other protection, is necessary in an assembly according to the invention.

[0014] The avionics bay according to the invention may include the following additional features, alone or in combination: The fastener is located at the center of the electrical contact base; the flexible clip includes means for clamping the clamp onto the electrical circuit; the flexible clip has two jaws fixed one on top of the other; the electrical contact base is an added piece on one of the jaws; the electrical contact base and the two jaws are joined by riveting; the flexible clip has a sealing gasket arranged around the electrical contact base; the tab has a nut fixed on a face opposite the electrical contact surface, this nut cooperating with a screw constituting the fastening of the flexible clip; the flexible clip forms an angle between its conductive clamping jaw and the electrical contact base which is between 90° and 150°; the tab forms an angle between its fixing tab and its electrical contact surface which is between 90° and 150°;The angle of the flexible clip formed between its conductive clamping jaw and the electrical contact base, and the angle of the tab formed between its fixing tab and its electrical contact surface, are substantially equal; the flexible clip has a rim, and the tab has a rim, these two rims being in plane-to-plane contact. PRESENTATION OF THE FIGURES

[0015] Other features and advantages of the invention will become apparent from the following non-limiting description, with reference to the accompanying drawings in which: [ Fig.1 ] There figure 1 illustrates an avionics bay; Fig.2 ] There figure 2 represents a shelf in the avionics bay of the figure 1 ; Fig.3 ] There figure 3 represents the shelf of the figure 2 , with the module connectors and external connection interface removed; Fig.4 ] There figure 4 represents the entire interconnection of the shelf of the figure 2 ; Fig.5 ] There figure 5 represents the shelf of the figure 3 view from below; Fig.6 ] There figure 6 represents the shelf of the figure 2 cross-sectional view; Fig.7 ] There figure 7 represents a reference potential setting clip, from the shelf of the figure 2 ; Fig.8 ] There figure 8 represents a shelf tab of the figure 2 ; Fig.9 ] There figure 9 represents the staple of the figure 7 cross-sectional view; Fig.10 ] There figure 10 illustrates a variant of the staple of the figure 7 ; Fig.11 ] There figure 11 represents the staple of the figure 10 mounted on a shelf. DETAILED DESCRIPTION

[0016] There figure 1 is a schematic representation of an avionics bay 1 which is a particularly advantageous environment for implementing the fixing and reference potential setting assembly according to the invention.

[0017] This avionics bay 1 has two side posts 2, 3 between which shelves 4 extend. Each shelf 4 is formed of a box whose hollow part extends between a ventilation wall 10 and a support platform 5 for rack-mountable electrical modules 6 mounted on the shelf 4.

[0018] The electrical modules 6 are, for example, electrical devices, power electronics, computing devices related to navigation, security, air conditioning functions, etc. These modules 6 are called rack-mountable because they are mounted on shelves 4 in a removable manner, thanks to support brackets (not shown in this schematic view of the figure 1 ) to facilitate the maintenance and replacement of these modules. These 6-inch rack-mountable electrical modules are also called LRUs (Line-Replaceable Units). Examples include modules that conform to the ARINC aeronautical standard.

[0019] Each shelf 4 includes, in addition to the modules 6, an external connection interface 7 equipped with interface connectors 8. The aircraft's electrical circuit is connected to the avionics bay 1 via these interface connectors 8.

[0020] The external connection interface 7 of each shelf 4 is connected to each of the modules 6 mounted on that shelf 4 via an interconnection tray 9 extending parallel to the support platform 5, on the opposite side to the modules 6. In other words, the support platform 5 is located between the modules 6 and the interconnection tray 9, for each shelf 4.

[0021] In this example, avionics bay 1 also includes an air circulation cooling system. This cooling system maintains the electrical and electronic equipment in modules 6 at an acceptable temperature, given their large number, density, and the heat they generate.

[0022] This cooling system organizes an airflow represented schematically on the figure 1 indicated by arrows. In this example, fresh air is injected into the avionics bay 1 through one of its uprights 2 and then distributed into the shelves 4, which form ducts channeling this fresh air through the modules 6. Different sections of each shelf 4 have through-ventilation openings (not shown in this schematic view of the figure 1 allowing cooling air to pass through module 6 to cool it.

[0023] The air heated by passing through modules 6 is then recovered in shelves 4 which vent the hot air towards the other upright 3 of avionics bay 1 to then be evacuated from avionics bay 1.

[0024] Flow separation walls 11 within the boxes formed by the shelves 4 allow the fresh and hot air flows to be separated in each shelf 4 if necessary.

[0025] There figure 2 represents one of the shelves 4 in avionics bay 1. On this figure 2 Modules 6 were not shown. Only the support chairs 12, designed to accommodate these modules 6, were shown on the figure 2 In this example, the support chairs 12 comply with the ARINC standard and allow for the mechanical fixing and electrical connection of compatible modules 6. Mechanical locking is ensured in particular by knobs 13, while the electrical connection of the modules 6 is ensured by module connectors 14.

[0026] In the example shown on the figure 2 Five support chairs 12 are mounted on the support platform 5 of the shelf 4, thus allowing five rack-mountable electrical modules to be received. These modules are secured by the knobs 13 and connected electrically to the aircraft's electrical circuit via the module connectors 14. The knobs 13 are located on the front of the support chairs 12, i.e., the part accessible to the user when facing the avionics bay.

[0027] As described previously, shelf 4 also includes an external connection interface 7 with interface connectors 8 to connect all the modules of shelf 4 to the aircraft's electrical circuit, to provide power and communication with all the modules 6 which are intended to be mounted in the support chairs 12. The external connection interface 7 is also fixed to the support platform 5.

[0028] Shelf 4 also includes a plurality of rigid rear printed circuit boards 15. One rear printed circuit board 15 is provided for each module connector 14. Each rear printed circuit board 15 is thus positioned opposite the module connector 14 of a support chair 12. Each rear printed circuit board 15 and its corresponding module connector 14 are rigidly fixed to each other.

[0029] The rear printed circuit boards 15 are each protected by a protective cover 16. On the figure 2 , three of the rear printed circuit boards 15 have been shown with their protective shell 16, while two of the rear printed circuit boards 15 are shown without their protective shell 16 to make the rear printed circuit boards 15 visible.

[0030] The support chairs 12 are each pierced with ventilation holes 17 through which fresh air from the shelf 4 passes through the module 6 which will be mounted on this support chair 12.

[0031] Each of the rear printed circuit boards 15, on the one hand, and the external connection interface 7, on the other hand, are connected to the interconnection board 9 (not visible on the figure 2 ) by a flexible printed circuit 18, 19. Each protective shell 16 advantageously protects a rear printed circuit 15 and also its flexible printed circuit 18.

[0032] The protective shells 16 are further equipped at their lower part with retaining tabs 61 or protruding lugs to ensure the retention of the interconnection tray 9 once installed at the rear of each rear printed circuit board 15. The protective shells 16 thus provide an additional function of retaining the interconnection tray 9.

[0033] There figure 3 represents the shelf of the figure 2 with its 14 module connectors removed and with its external connection interface 7 open.

[0034] Each of the support chairs 12 has a back panel 22 extending perpendicularly to the support platform 5, and in which a connection window 20 is formed. Each module connector 14 is mounted on a connection panel 21 which is fixed (when the shelf is in its mounted position) to the figure 1 ) on the edges of the connection window 20 so that the module connector 14 protrudes from the connection window 20 in order to connect the received module in the support chair 12. The connection walls 21 and the module connectors 14 thus each extend perpendicularly to the support platform 5.

[0035] The module connectors 14 can be of any type suitable for connecting a module 6 when it is inserted into the corresponding support chair 12 until it abuts against its base 22. The module connectors 14 can be a single piece or, conversely, made up of several sub-connectors. These module connectors 14 are equipped with pins extending parallel to the support platform 5, towards the module installed on the support chair 12. These pins are interconnection pins that are advantageously removable and replaceable.

[0036] For each support chair 12, the connecting wall 21 is attached to the rear printed circuit board 15 by means of a spacer 23. The spacer 23 consists of a flange extending perpendicularly to the rear printed circuit board and positioned around its perimeter. The connecting wall 21 is fixed to one side of the spacer 23, and the rear printed circuit board 15 is fixed to the other side of the spacer 23, the printed circuit board thus being parallel to the connecting wall 21. The connecting wall 21 can advantageously be fixed to the base wall 22 by means of fasteners screwed into the spacer 23.

[0037] The pins of the module connector 14 are connected to the corresponding rear printed circuit board 15 by any wiring method, such as soldered conductors, or more advantageously by press-fit technology. The pins of each module connector 14 are thus removable and extended by rigid conductive leads that are crimped into the corresponding rear printed circuit board 15. These rigid conductive leads are commonly called "tulips." This makes mounting and connecting the module connectors 14 quick and reliable. The conductive leads 56 are shown in the figure 6 .

[0038] The rigid fixing provided by the spacer 23 allows here the use of rigid connections between the module connector 14 and the rear printed circuit board 15 and guarantees the longevity of these connections over time thanks to an assembly where relative movements of the module connector 14 and the corresponding rear printed circuit board 15 are not permitted.

[0039] There figure 3 This makes visible the possibility of movement of the module connectors 14 when they have been removed from their connection window 20. This movement is made possible by the flexibility of the flexible printed circuit boards 18. For each module, the connection wall 21 is preferably attached to the connection window 20 by screws accessible from inside the support chair 12, i.e., from the front face (on the side with the knobs 13) of the shelf. An operator can thus easily access a module connector 14 by removing the module from a support chair 12, unscrewing these screws, and positioning the connector 14 in its correct position. figure 3 thanks to the flexibility of the flexible printed circuit board 18.

[0040] Regarding the external connection interface 7, it consists of a connection box 24 comprising an external connection wall 25 (which is shown disassembled on the figure 3 ). An external connection printed circuit board 26 is fixed parallel to the external connection wall 25 by means of spacers 27 and is connected to the flexible printed circuit board 19.

[0041] Interface connectors 8 (visible at the figure 2 The interface connectors 8 are connected to the external connection circuit board 26 in a manner similar to the module connector 14. The interface connectors 8 thus have pins (not shown for simplicity in the figures) connected by any suitable technique to the traces of the external connection circuit board 26, and in particular by press-fit technology made possible by the rigid retention of the external connection circuit board 26 relative to the external connection wall 25. The pins of each interface connector 8 are thus extended by rigid conductive rods that are crimped into the external connection circuit board 26. The pins of the interface connectors 8 and these rigid conductive rods can be mounted in the same way as the pins and rods of the module connectors 14.

[0042] The external connection interface 7 provides, at the interface connectors 8, the necessary connections for linking all the pins of the module connectors 14 to the aircraft's electrical circuit. The connection box 24 also allows for the housing of additional equipment such as fuses, connectors, or displays for maintenance purposes; this additional equipment can be directly mounted on the external connection printed circuit board 26.

[0043] There figure 4 illustrates the implementation of the electrical connection between the module connectors 14 and the interface connectors 8. This figure 4 represents an interconnect assembly of which the flexible printed circuits 18, 19 and rigid 15, 26 have been shown, in a flat position illustrating a preferred position for the manufacture of this interconnect assembly.

[0044] The rear printed circuit boards 15 and the external connection printed circuit board 26 are each connected to the interconnection tray 9 by means of their respective flexible printed circuit boards 18 and 19. In this example, the interconnection tray 9 is a printed circuit board bearing conductive connecting traces 28 linking the flexible printed circuit boards 18 to the flexible printed circuit boards 19 and possibly some of the flexible printed circuit boards 18 to each other. The conductive connecting traces 28 extend, either continuously or with possible interconnections, from the rear printed circuit boards 15 to the external connection printed circuit board 26.

[0045] On the figure 4 Only a few conductive connection traces 28 have been schematically represented, it being understood that a significant number of modules 6 can be mounted on a shelf 4, which generates a large number of low- and high-power electrical connections to be made between the module connectors 14 and the interface connectors 8, or between two connectors 14. Since the surface area of ​​the interconnection tray 9 is limited only by the surface area of ​​the shelf 4 itself, this surface area of ​​the interconnection tray 9 can be adapted to support these numerous conductive traces 28. Furthermore, the interconnection tray 9 can be made of a multi-layered printed circuit board if the number of conductive traces 28 so requires.

[0046] Each pin of a module connector 14 can thus be connected to a pin of an interface connector 8 by a circuit passing through the rear printed circuit board 15, the flexible printed circuit board 18, the interconnection tray 9, the flexible printed circuit board 19, and the external connection printed circuit board 26.

[0047] The interconnection platform 9 also includes a plurality of through ventilation ports 29 intended to participate in the cooling function of the avionics bay.

[0048] The interconnection tray 9 also includes reference potential-setting clips 30 which allow both the mechanical retention of the interconnection tray 9 relative to the corresponding shelf 4 and the electrical connection of the ground of the interconnection tray 9 with the metal structure of the shelf 4. The modules 6 and the external connection interface 7 can thus be reliably grounded to the avionics bay 1 by conductive tracks of the interconnection tray 9.

[0049] According to a preferred feature, the interconnect board 9, the rear printed circuit boards 15, the external connection printed circuit board 26, and the flexible printed circuit boards 18, 19 are manufactured as a single piece. The interconnect assembly shown in the figure 4 (with the exception of the clips 30) is thus constituted by a single printed circuit which includes rigid portions 15, 9, 26, and flexible portions 18, 19. However, the interconnection board 9 can also be made of a flexible printed circuit.

[0050] This enables extremely rapid and reliable manufacturing for the complete interconnection system of the figure 4 .

[0051] Alternatively, if modularity properties are preferred for the interconnection assembly, the flexible printed circuit boards 18 connected to the rear printed circuit boards 15 can be connected to the interconnection tray 9 via detachable connectors, which allows rear printed circuit boards 15, and therefore module connectors 14, to be removed or added to the same interconnection tray 9.

[0052] Similarly, the flexible printed circuit board 19 of the external connection printed circuit board 26 can either be made in one piece with the interconnection board 9 or, alternatively, connected by detachable connectors allowing the external connection printed circuit board 26 to be changed to replace it if it is defective, or to have the choice of connecting different external connection interfaces 7 on the same interconnection board 9.

[0053] The flexible printed circuits 18, 19 allow perpendicular elements to be connected. A low bending constraint is therefore imposed on these flexible printed circuits 18, 19, which ensures reliability.

[0054] There figure 5 represents shelf 4 of the figure 3 , view from below. The figure 5 illustrates a first embodiment of the assembly of the interconnection platform 9 with the shelf 4.

[0055] In this example, the shelf 4 forms a box inside which the cooling air circulates, entering and exiting the box through ventilation openings 31. The support platform 5 delimits the upper part of this box while the ventilation wall 10 delimits the lower part of this box, with lateral profiles 32 further delimiting the lateral edges of the box.

[0056] The interconnection plate 9 is fixed opposite the ventilation wall 10 by means of the reference potential setting clips 30 which are fixed on one of the lateral profiles 32 as well as by additional clips 33 whose function is solely to clamp the interconnection plate 9 and fix it to the ventilation wall 10. In addition, as described previously, the protective shells 16 have retaining tabs 61 for the interconnection plate 9 and thus also contribute to the optimal retention of the interconnection plate 9.

[0057] On the figure 5 The interconnection tray 9 is fitted with a protective cover 34 covering almost its entire surface to ensure its physical protection and electrical insulation. The protective cover 34 is itself fitted with through ventilation openings 35 arranged opposite the ventilation openings 29 of the interconnection tray 9.

[0058] There figure 6 is a schematic cross-sectional view showing the arrangement relative to this first embodiment. On this figure 6 A module 6, shown in cross-section, is mounted on a support chair. The enclosure delimited by the shelf 4 includes an inlet duct 36 and an outlet duct 37 which are separated by the flow separation wall 11.

[0059] In this example, the support platform 5 consists of two horizontal edges of the side profiles 32 forming two parallel flat crossbeams on which the support brackets rest. The upper part of the inlet duct 36 is closed by the support brackets, and the calibration of the cross-section of the cooling air distributed to the module 6 is achieved by the diameter and number of ventilation openings 17 in the support brackets.

[0060] As mentioned previously in relation to the figure 1 The inlet duct 36 distributes fresh air to module 6 via the ventilation openings 17 of the support chair, and the outlet duct 37 allows the extraction of hot air that has passed through module 6, which is located on the shelf below (not shown). According to this first embodiment, this hot air is drawn into the outlet duct 37 successively through the ventilation openings 35 of the protective cover 34, then the ventilation openings 29 of the interconnection tray 9, and then ventilation openings 38 passing through the ventilation wall 10, these openings preferably being opposite each other as shown in the figure. figure 6 .

[0061] As an alternative to the figure 6 The ventilation openings 29 of the interconnection tray 9 are smaller than the ventilation openings 35 and 38 of the protective cover 34 and the ventilation wall 10. Therefore, the ventilation openings 35 and 38 of the protective cover 34 and the ventilation wall 10 are oversized, while the ventilation openings 29 of the interconnection tray 9 ensure the calibration of the air permeability of the inlet of the outlet duct 37. Calibrating this air permeability is an important element of the cooling system, determined during the design of the avionics bay, based on the arrangement of the various components that generate and channel the cooling air. Since the calibration of this permeability is achieved by the interconnection tray, the shelves (and in particular the ventilation walls) and the protective covers 34 can be standardized.

[0062] The interconnection tray 9 is directly fixed to the shelf 4 (or even to the ventilation wall 10), with or without a sealing gasket 53 or spacer maintaining a gap between this wall 10 and the interconnection tray 9. In the present example, the fixing of the interconnection tray 9 is ensured by the reference potential setting clips 30.

[0063] THE figures 7 à 9 illustrate a fixing and reference potential setting assembly which includes one of the clips 30 allowing the interconnection plate 9 to be connected to the electrical reference potential and which allows the mechanical retention of this interconnection plate 9.

[0064] The clip 30 is a flexible clip forming a clamp with two jaws 39, 40 that clamp the interconnection tray 9 together. At least one of the two faces of the interconnection tray 9 that is in contact with the clip 30 has a conductive ground area 41. The conductive tracks of the interconnection tray 9 that must be connected to the electrical reference potential of the avionics bay must be electrically connected to this conductive area 41.

[0065] The clip 30 is made of an electrically conductive material so that, when the clip 30 is clamped onto the interconnection plate 9, electrical continuity is established between the conductive area 41 and a heel 42 which is integral with one of the two jaws 39, 40. The heel 42 has in its center an opening allowing the passage of a fixing screw 43.

[0066] Optionally, for better longevity and connection security, the clip 30 is tightened by rivets 44 on the interconnection plate 9 and the two jaws 39, 40 are tightened against each other by rivets 45 on either side of the potential setting heel 42.

[0067] An O-ring 46 can also be arranged around the potential setting heel 42 to ensure the sealing of the reference potential setting.

[0068] There figure 8 The figure represents, in perspective, a portion of one of the side profiles 32 of the shelf 4, this portion being intended to receive the attachment of the clip 30. For this purpose, the side profile 32 has a tab 47 electrically and mechanically connected to the side profile 32. In this example, the tab 47 has a fixing tab 59 attached by welding or, as illustrated in the figure 8 by riveting. The tab 47 has a riveted nut 48 for its cooperation with the fixing screw 43. The tab 47 has, on its face opposite the riveted nut 48, an electrical contact surface 57.

[0069] There figure 9 represents in cross-section, at the level of the clip 30, the assembly of an interconnection plate 9 and a shelf 4. The fixing screw 43 is screwed and tightened on the crimped nut 48 so that the O-ring 46 is compressed and the potential-setting heel 42 is pressed against the tab 47.

[0070] The clip 30 thus provides mechanical support for the interconnection board 9 without locking it in place, thanks to the flexibility of the clip 30 and the tab 47. This avoids mechanical stresses within the printed circuit board constituting the interconnection board 9, while ensuring firm support for this interconnection board 9. The assembly of the interconnection board 9 and its adjustment to the reference potential is accomplished by the single operation of tightening the fixing screw 43. To facilitate the positioning of the clip 30 relative to the tab 47, the clip 30 has a lip 49 and the tab 47 has a lip 50; these two lips 49 and 50 are in plane-to-plane contact when the fixing screw 43 is opposite the riveted nut 48.

[0071] With reference to the figure 9 The clip 30 and the tab 47 allow the interconnection plate 9 to be mounted relative to a surface parallel to it (the surface 58 of the side profile 32). The tab 47 has an angle greater than 90° between its electrical contact surface 57 and its fixing tab 59 for this purpose. Furthermore, the two jaws 39, 40 of the clip 30 have the same angle between their clamping portion and their portion bearing the heel 42. This angle is preferably between 90° and 150°. The offset created by this angle allows the assembly to be visible to the figure 9 , this assembly providing optimal dynamic behavior for maintaining the electrical circuit made up of the interconnection plate 9.

[0072] THE figures 10 et 11 illustrate an alternative embodiment of the reference potential setting clip 30. In this variant, the ventilation wall 10 has a perpendicular lip 51, and the interconnection plate 9 is mounted opposite the ventilation wall 10 by attaching the clip 30 to this lip 51. The two jaws 39, 40 of the clip 30 are here made of right-angled parts adapted to clamp the interconnection plate 9 and hold it perpendicular to the lip 51 while ensuring its reference potential setting.

[0073] The 30 clips eliminate the need for braids, cables and ground lugs that are usually used in addition to conventional printed circuit board fastening methods.

[0074] The assembly and connection on a shelf 4 of such an interconnection assembly is achieved by a very limited number of operations reduced to the fixing of the clips 30, 33 on the shelf 4, the fixing of the connection walls 21 on the retaining chairs 12, and the mounting of the external connection interface 7. These assembly operations are very limited in number compared to the multiple wiring operations required in the avionics bays of the prior art, and this with greater connection security by limiting the risks of error.

[0075] Alternative embodiments of the avionics bay described can be considered without departing from the scope of the invention. For example, choosing a rigid interconnection tray 9 may lead to undersizing the shelf 4. It is possible, for instance, to reduce the thicknesses planned for the walls of the shelf 4, and in particular the thickness of the ventilation wall 10, by taking into account the additional rigidity provided by fixing the interconnection tray 9 to the shelf 4.

[0076] Similarly, if the choice of a flexible printed circuit interconnection board 9 is made, it is possible to provide a flexible or even deformable shelf 4, the flexibility of the interconnection board 9 accompanying this deformation without inducing stress which could harm the conductive tracks of the connection 28.

[0077] The protective shells 16 of the rear printed circuit boards 15 and the protective covers 34 of the interconnection board can also ensure electromagnetic compatibility functions, for example by electromagnetically isolating their contents.

[0078] The integration of components on the front panel of shelf 4 is made possible by the interconnection system. figure 6 This illustrates an example of integrating a device 54 into the front of a shelf 4. This device may, for example, include displays, relays, and control buttons. This front-mounted device 54 requires no special wiring other than the addition of a flexible printed circuit board 55 connected on one side to this front-mounted device 54 and on the other side to the interconnection tray 9.

[0079] In addition, cable bundles can replace the flexible printed circuits 18, 19 connecting the rear printed circuits 15 and the external connection printed circuit 26 to the interconnect board 9.

Claims

1. A reference potential setting and fixing assembly for an electrical circuit, comprising an electrically conductive flexible fastener (30) which comprises: - a conductive clamp for clamping the electrical circuit; - an electrical contact heel (42); - a fixing (43) adapted to clamp the electrical contact heel (42) against an electrical contact surface; this assembly being characterized in that it comprises an electrically conductive tongue (47) comprising a fixing tab (59) for fixing to a structure and having an electrical contact surface (57), the flexible fastener (30) being fixed to the tongue (47) such that the electrical contact heel (42) is arranged against the electrical contact surface (57).

2. The assembly as claimed in claim 1, characterized in that the fixing (43) is arranged at the center of the electrical contact heel (42).

3. The assembly as claimed in either one of the preceding claims, characterized in that the flexible fastener (30) comprises means (44) for clamping the clamp on the electrical circuit.

4. The assembly as claimed in any one of the preceding claims, characterized in that the flexible fastener (30) comprises two jaws (39, 40) fixed to one another.

5. The assembly as claimed in claim 4, characterized in that the electrical contact heel (42) is a part attached to one of the jaws (39, 40).

6. The assembly as claimed in claim 5, characterized in that the electrical contact heel (42) and the two jaws (39, 40) are secured by riveting.

7. The assembly as claimed in any one of the preceding claims, characterized in that the flexible fastener (30) comprises a tightness seal (46) arranged around the electrical contact heel (42).

8. The assembly as claimed in one of the preceding claims, characterized in that the tongue (47) comprises a nut (48) fixed to a face opposite the electrical contact surface (57), this nut (48) cooperating with a screw (43) constituting the fixing of the flexible fastener (30).

9. The assembly as claimed in one of the preceding claims, characterized in that the flexible fastener (30) forms an angle between its conductive clamp and the electrical contact heel (42) which is between 90° and 150°.

10. The assembly as claimed in claim 9, characterized in that the tongue (47) forms an angle between its fastening tab (59) and its electrical contact surface (57) which is between 90° and 150°.

11. The assembly as claimed in claim 10, characterized in that the angle of the flexible fastener (30) formed between its conductive clamp and the electrical contact heel (42), and the angle of the tongue (47) formed between its fixing tab (59) and its electrical contact surface (57), are substantially equal.

12. The assembly as claimed in one of the preceding claims, characterized in that the flexible fastener (30) comprises a flange (49), and in that the tongue (47) comprises a flange (50), these two flanges (49, 50) being in flat-on-flat contact.