Device for establishing an electrical connection

[0001] This application is a national stage completion of PCT/EP2004/009825 filed Sep. 3, 2004 which claims priority from German Application Serial No. 203 14152.0 filed Sep. 11, 2003.

[0002] The invention relates to a device for establishing an electrical connection between two parts, in particular vehicle parts, which can move such that they can pivot with respect to one another about an axis.

[0003] Parts which can move such that they can pivot with respect to one another and between which an electrical connection is required for power supply purposes are found in all sectors of engineering.

[0004] The term vehicle parts is understood to mean both motor vehicles and commercial vehicles as well as other landcraft, seacraft or aircraft. Vehicles of the abovementioned type require a power connection at a large number of different points in order to connect various terminals, such as headlamps, rear windshield heaters, windshield wipers or the like. Since the vehicles have a large number of vehicle parts which can move such that they can pivot with respect to one another, these vehicle parts need to be bridged in a reliable manner by an electrical connection in order that there is a power connection available in the desired areas.

[0005] In the case of motor vehicles or commercial vehicles, the vehicle parts which can move such that they can pivot with respect to one another are generally the vehicle frame, towards which a large number of different vehicle parts can be pivoted. In this case, this vehicle part is, for example, the tailgate (in a single-part or two-part embodiment), the doors, loading openings or the engine hood. In particular if the two vehicle parts which can move such that they can pivot with respect to one another are in the form of the vehicle frame and the tailgate, particularly high requirements need to be placed on the electrical connection between these two vehicle parts, since terminals need to be operated via the electrical connection which have a high current consumption, such as the rear windshield heater, the rear lights or a windshield wiper. Furthermore, the electrical connection also serves the purpose of supplying current to an interior lighting system fixed to the tailgate.

[0006] The end consumers mentioned are generally operated and controlled independently of one another such that a large number of individual connections is not required.

[0007] It is known from the general prior art to arrange a free-running cable run between a vehicle frame and a tailgate, said cable run being allowed so much play that it is possible for the tailgate to be both completely opened and closed. One disadvantage here, however, is the fact that the cable run is bent or buckled by the continuous opening and closing operation of the tailgate. One complicating factor is the fact that this even takes place at relatively low temperatures, with the result that the ability of the cable run to function throughout the life of the vehicle is not reliably ensured. Owing to the play which the cable run necessarily needs to have, there is also always the risk of the cable run being ripped out or damaged by inadvertently being hooked.

[0008] The present invention is therefore based on the object of providing a device for establishing an electrical connection between two parts which can move such that they can pivot with respect to one another about an axis, which device ensures a reliable and cost-effective electrical connection.

[0009] This object is achieved according to the invention by the characterizing clause of claim 1.

[0010] Owing to the arrangement of a current transmitter unit and a current receiver unit in the region of the axis about which the movable parts are pivoted, it is possible to achieve, in a simple manner, a situation in which the current transmitter unit and the current receiver unit come into contact with one another in a reliable manner at least in an end position of the pivoting movement of the parts. Manufacturing tolerances or gap sizes in this case do not have any negative influence on the ability of the current transmitter unit to come into contact with the current receiver unit.

[0011] A cable run for bridging the two movable parts which can pivot with respect to one another is thus no longer required.

[0012] The inventor has recognized, in manner which is not obvious, that, for example when the first part is in the form of a vehicle frame and the second part is in the form of a tailgate, it is completely unproblematic for the current transmitter unit to become detached from the current receiver unit during the opening operation, since the loads, for example a rear windshield heater, a rear windshield wiper or the rear lights, do not require any current when the tailgate is in the open state. Without any loss of convenience, it is therefore possible to isolate the electrical connection between the two vehicle parts. When the tailgate is closed, the current receiver unit again makes contact with the current transmitter unit, with the result that the loads are provided with a corresponding supply. The arrangement of the current transmitter unit and the current receiver unit is not restricted to the region of the axis of the pivot joint, for example a hinge. The current transmitter unit and the current receiver unit can instead be arranged at any point along the theoretical axis of rotation.

[0013] It is advantageous that manufacturing-related and use-related tolerances in the distance between the tailgate and the vehicle frame in the closed state do not have any negative effects on the contact-making between the current transmitter unit and the current receiver unit, since the distance between the tailgate and the vehicle frame is generally not dependent on tolerances in the region of the axis.

[0014] It is advantageous if the parts which can pivot with respect to one another are connected by means of at least one hinge, and the current transmitter unit and the current receiver unit are each arranged on one hinge half.

[0015] An arrangement of the current transmitter unit and the current receiver unit on in each case one hinge half of the hinge have proven to be particularly suitable. The pivoting movement of the parts with respect to one another is essentially predetermined by the hinges, with the result that the parts also close in a particularly precise manner in terms of dimensions in the region of the hinges. As a result of the fact that no actual changes need to be made to the parts, such as holes for holders or the like, the current transmitter unit and the current receiver unit can be used in a simple manner, even retrospectively, for establishing an electrical connection between the parts.

[0016] One design-related refinement of the invention may provide for the current transmitter unit and/or the current receiver unit to be connected to the respective hinge half by means of a dovetail connection.

[0017] Such a connection is robust, can be performed in a simple manner in design terms and is cost-effective. Furthermore, it is possible in a simple manner to replace the current transmitter unit or the current receiver unit for repair purposes.

[0018] One development of the invention may provide for the surfaces, in the form of flat contacts, of the contact elements of the current transmitter unit and/or the current receiver unit to have a concave or outwardly curved shape.

[0019] Owing to the pivoting movement of the movable parts, to which the current transmitter unit and/or the current receiver unit are fixed directly or via the hinges, the current transmitter unit and the current receiver unit come into contact by means of a sequence of motions which generally corresponds to an arc (i.e. they move radially with respect to one another). The concave shape of the contact elements or the flat contacts of the current transmitter unit and/or the current receiver unit means that the flat contacts slide or rub against one another before the end position is reached. As a result, any contamination, deposits or the like are rubbed off from the contacts, with the result that reliable contact can be made in the end position.

[0020] It is advantageous here if the contact elements are elastically or resiliently mounted in the current transmitter unit and/or the current receiver unit.

[0021] This makes it possible for the contact elements of the current transmitter unit or the current receiver unit to be able to part, if appropriate, in the direction of pressure during the sliding or rubbing operation. Damage to the contact elements is thus avoided, whilst at the same time it is ensured that the contact elements or the flat contacts rub against one another in a cleaning manner. In order for them to be mounted elastically, the contact elements can be arranged on their rear sides facing away from the flat contacts in an elastic layer, for example made from rubber or silicone. The elastic layer makes it possible for the contact elements to part and move back in a defined manner. The contact elements are preferably mounted elastically, independently of one another. For this purpose, the contact elements can, for example, be mounted on a silicone cushion.

[0022] As an alternative or in addition to this, provision may also be made for the contact elements of the current transmitter unit and/or the current receiver unit to be mounted in an at least partially elastic wall of the associated current transmitter unit or the current receiver unit.

[0023] The arrangement in an at least partially elastic wall likewise makes it possible for the contact elements to part if the pressure exceeds a predetermined value. In this case, it is also advantageous that the individual contact elements can thus move independently of one another, which ensures that each contact element comes into contact with the envisaged contact element of the respective other unit without being influenced by the other contact elements. One particularly advantageous embodiment of the elastic wall is described in DE 199 30 642.

[0024] Advantageous developments and refinements of the invention will be described in the further dependent claims.

[0025] A hinge having means for connecting a current transmitter unit and a current receiver unit as claimed in one of claims 1 to 16 is described in claim 17.

[0044] As can be seen from FIG. 1 to FIG. 6, the device according to the invention for establishing an electrical connection has a current transmitter unit 1 and a current receiver unit 2. The current transmitter unit 1 is in this case arranged on a first vehicle part 3, and the current receiver unit 2 is arranged on a second vehicle part 4. The two vehicle parts 3, 4 are shown as a block diagram in FIG. 2. In this case, the first vehicle part 3 may be, for example, the frame of a vehicle (not illustrated in any more detail). The second vehicle part 4 may be in the form of, for example, a tailgate of a vehicle.

[0045] Since the specific design of the vehicle parts is not critical to the embodiment of the invention, a detailed illustration in this regard has been dispensed with.

[0046] The illustrated device according to the invention is not restricted to vehicle parts. The solution according to the invention can instead be used in all sectors of engineering.

[0047] The current transmitter unit 1 and the current receiver unit 2 are arranged in the region of an axis 5, about which the vehicle parts 3, 4 can move with respect to one another in a pivotable manner.

[0048] In the exemplary embodiment illustrated, the current transmitter unit 1 and the current receiver unit 2 are arranged on a hinge 6. In this case, the current transmitter unit 1 and the current receiver unit 2 are each arranged on one hinge half 7a, 7b. The hinge halves 7a, 7b are separated by the axis of the hinge 6. The axis of the hinge 6 consequently corresponds to the axis 5, about which the vehicle parts 3, 4 can be pivoted with respect to one another.

[0049] In the exemplary embodiment, the current transmitter unit 1 and the current receiver unit 2 are arranged on the hinge 6, but the invention is not restricted to this embodiment. The current transmitter unit 1 and the current receiver unit 2 can be arranged at any desired point along a theoretical axis, about which the vehicle parts 3, 4 can be pivoted with respect to one another. An actual axis of rotation or pivoting axis does not need to be provided for this purpose; it is sufficient for the current transmitter unit 1 or the current receiver unit 2 to be arranged along a theoretical pivoting axis, about which the vehicle parts 3, 4 can be pivoted.

[0050] As shown in FIG. 1, the current transmitter unit 1 and the current receiver unit 2 come into contact in an end position of the pivoting movement of the vehicle parts 3, 4. This end position may be, for example, a position in which the tailgate of the vehicle is closed. The tailgate may be a single-part or two-part tailgate.

[0051] The exemplary embodiment provides for the current transmitter unit 1 and the current receiver unit 2 to be connected to the respective hinge half 7a, 7b by means of a dovetail connection 8, 9.

[0052] As can be seen in the exemplary embodiment shown in FIG. 3, in this case the hinge half 7b has a dovetail-like projection 9a in order to connect it to the current receiver unit 2. The current receiver unit 2 correspondingly has a dovetail-shaped receptacle 9b. Analogously, as can be seen in FIG. 5, the hinge half 7a, which is provided for the arrangement of the current transmitter unit 1, is provided with a dovetail-like projection 8a. The current transmitter unit 1 correspondingly has a dovetail-shaped receptacle 8b, with the result that a dovetail connection 8 is formed between the current transmitter unit 1 and the hinge half 7a.

[0053] The arrangement of the current transmitter unit 1 or the current receiver unit 2 on the hinge 6 is thus possible in a simple manner. If required, the connection can be detached again in a likewise simple manner. In order to prevent the current transmitter unit 1 or the current receiver unit 2 from being detached unintentionally, an additional fixing may be provided by means of a screw or the like (not illustrated in any more detail).

[0054] FIG. 2 shows contact elements 1a of the current transmitter unit 1 and (using dashed lines) contact elements 2a of the current receiver unit 2. The contact elements 1a, 2a each have a surface in the form of a flat contact 1b, 2b for contact-making purposes. The contact elements 1a and 2a are arranged such that they or their flat contacts 1b, 2b come into contact with one another in the end position illustrated in FIG. 1. The contact elements 1a and 2a will be described in more detail below.

[0055] The current transmitter unit 1 has a dovetail-shaped receptacle 10 on its rear side facing away from the flat contacts 1b. The dovetail-shaped receptacle 10 can be seen in FIG. 3 and FIG. 8. In FIG. 1 and FIG. 2, the dovetail-shaped receptacle 10 is illustrated using dashed lines. The dovetail-shaped receptacle 10 is aligned with a dovetail-shaped receptacle 11 of the hinge half 7a. This dovetail-shaped receptacle 11 is illustrated in FIG. 4 and FIG. 13. In this case, FIG. 1 and FIG. 2 likewise show the dovetail-shaped receptacle 11 using dashed lines. The dovetail-shaped receptacle 10, in conjunction with the dovetail-shaped receptacle 11, serves the purpose of fixing the current transmitter unit 1 on the hinge half 7a. For this purpose, as illustrated in FIG. 2, a rear wall or a fixing plate 12 is inserted into the dovetail-shaped receptacle 10 and the dovetail-shaped receptacle 11. The fixing plate 12 thus passes through both the dovetail-shaped receptacle 10 of the current transmitter unit 1 and the dovetail-shaped receptacle 11 of the hinge half 7a. Owing to the fixing plate 12 and the dovetail-shaped receptacles 10, 11, it is no longer possible for the dovetail connection 8 between the current transmitter unit 1 and the hinge half 7a to be detached.

[0056] The fixing plate 12 makes it possible to fix the current transmitter unit 1 without any holes being required, which would restrict the interior of the current transmitter unit 1.

[0057] The current transmitter unit 1 and the current receiver unit 2 may each have a plastic housing. The contact elements 1a and 2a are arranged in the current transmitter unit 1 and, respectively, the current receiver unit 2 and/or are designed in terms of their shape such that the flat contacts 1a, 1b of the contact elements 1a, 2a rub against one another before the end position illustrated in FIG. 1 is reached.

[0058] In addition, FIG. 2 shows a preferred refinement of the contact elements 1a and the contact elements 2a. FIG. 9 shows a section through a preferred refinement of a current transmitter unit 1 having contact elements 1a.

[0059] As can be seen in FIG. 2 and FIG. 9, the flat contacts 1b of the contact elements 1a in a preferred embodiment have a concave or outwardly curved shape. As an alternative or in addition to this, the flat contacts 2b of the contact elements 2a of the current receiver unit 2 can also have a concave shape. The concave shape causes the contact elements 1a, 2a to come into contact with one another before the end position is reached. The flat contacts 1b, 2b therefore have any contamination or deposits removed from them.

[0060] In the embodiment of the current transmitter unit 1 illustrated as being preferred in FIG. 9, provision is made for the contact elements 1a to be mounted elastically. For this purpose, the current transmitter unit 1 has an elastic layer 13, for example made from silicone or rubber, which is arranged on the rear side which faces away from the flat contacts 1b of the contact elements 1a. The elastic layer 13 makes it possible for the contact elements 1a to move back in the direction of the elastic layer 13 above a specific pressure, which is produced by said contact elements 1a coming into contact with the contact elements 2a.

[0061] As an alternative or in addition to the elastic mounting of the contact elements 1a, the contact elements 2a can also be elastically mounted. Elastic mounting of the contact elements 1a is sufficient, however.

[0062] As an alternative to the flat contacts 1b having a concave shape, provision may also be made for the current transmitter unit 1 or, if appropriate, the current receiver unit 2 to have a concave surface, into which the flat contacts 1b or, if appropriate, the flat contacts 2b are inserted.

[0063] In a further embodiment (not illustrated), provision may also be made for the contact elements 1a, 2a of the current transmitter unit and, respectively, the current receiver unit 2 to be mounted in an at least partially elastic wall of the associated current transmitter unit 1 or the current receiver unit 2. In this case, the contact elements 1a, 2a can be cast or inserted in a fluid-tight manner into the at least partially elastic wall. The at least partially elastic wall may be in the form of, for example, a plastic membrane. One particularly preferred embodiment for this is described in DE 199 30 642, to which reference is made in this regard.

[0064] As can also be seen in FIG. 9 in conjunction with FIG. 7, the contact elements 1a are each connected to power supply lines 14, which lead to a current source (not illustrated).

[0065] As can be seen from the drawing, the current transmitter unit 1 in the exemplary embodiment has three contact elements 1a. The current receiver unit 2 correspondingly likewise has three contact elements 2a. Any other desired number of contact elements 1a, 2a is of course also possible for this purpose. The contact elements 1a, 2a can be used, for example, for supplying power to a rear windshield heater, a rear windshield wiper and rear lights.

[0066] As can be seen in FIG. 1, FIG. 2 and, in particular, FIG. 10, the current receiver unit 2 has a radius which at least partially surrounds the axis 5 of the hinge 6. This results in a particularly advantageous connection between the contact elements 2a and the contact elements 1a.

[0067] FIG. 11 shows the dovetail-shaped receptacle 9b of the current receiver unit 2 for connection to the dovetail-like projection 9a of the hinge half 7b.

[0068] FIG. 12 shows the contact elements 2a, which, analogously to the contact elements 1a, have flat contacts 2b having an essentially rectangular shape. The contact elements 2a are each connected to a line 15, which leads to a load.

[0069] FIGS. 13 to 17 show the hinge 6 having means for connecting the current transmitter unit 1 and the current receiver unit 2, in detail.

[0070] As can be seen in FIG. 13, the two hinge halves 7a, 7b have cutouts 17, through which the power supply lines 14 to the current transmitter unit 1 or the lines 15 from the current receiver unit 2 to a load can be passed in a simple manner. FIG. 13 also shows the dovetail-shaped receptacle 11, which is intended to be fixed to the fixing plate 12, as already described. Such a dovetail-shaped receptacle 11 can also be provided for fixing the current receiver unit 2 in the hinge half 7b.

[0071] The dovetail-shaped receptacle 11 runs at an angle of 90° with respect to the dovetail-like projection 8a, as can be seen from FIG. 13 in conjunction with FIG. 14.

[0072] FIGS. 13 and 14, and in detail FIGS. 16 and 17, show an individual contact element 16 for establishing an electrical connection between the two hinge halves 7a, 7b. The individual contact element 16 is in this case arranged on the axis 5. In this case, the exemplary embodiment provides for the individual contact element to be in the form of a spring disk 16, as is illustrated in FIG. 16 and FIG. 17. The spring disk 16 in this case serves the purpose of transmitting a low-volt voltage from the hinge half 7a to the hinge half 7b. It is thus advantageously possible for a voltage to be transmitted even in the open state of the hinge 6, i.e. when the contact elements 1a are not in contact with the contact elements 2a. The spring disk 16 can be used, for example, for supplying power to an interior lighting system.

[0073] In one alternative embodiment, the current transmitter unit 1 and the current receiver unit 2 can be provided with a magnetic triggering device, as is described in EP 0 573 471.