GB1581778A

GB1581778A - Electricity supply to at least one constructional unit comprising one or more electrical loads

Info

Publication number: GB1581778A
Application number: GB3434177A
Authority: GB
Original assignee: SWF Spezialfabrik fuer Autozubehoer Gustav Rau GmbH
Current assignee: SWF Auto Electric GmbH
Priority date: 1976-08-24
Filing date: 1977-08-16
Publication date: 1980-12-17
Also published as: ES461833A1; FR2363213B3; FR2363213A1; DE2637981A1; DE2637981B2; IT1085676B; BR7705078A

Description

(54) ELECTRICITY SUPPLY TO AT LEAST ONE CONSTRUCTIONAL UNIT COMPRISING ONE OR MORE ELECTRICAL LOADS (71) We, SWF-SPEZIALFABRIK FUR AUTOZUBEHOR GUSTAV RAU G.m.b.h., a joint stock company organised under the Laws of Germany, of Stuttgarter Strasse-119, 712 Bietigheim Bissingen, Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a wiring system for the supply of electricity to at least one constructional unit, which system comprises one or more units, which each include one or more electrical loads (such as a light bulb or instrument), and a flat cable having a plurality of metal conductors embedded in parallel in an insulating strip.

Constructional units with several electrical loads are known, e.g. instrument clusters, or rear lamps for automotive vehicles, in which the wiring between the loads is effected by a flexible printed circuit. The conductive connection to the load is effected by direct engagement of contact springs associated with the load on the metal conductors of the flexible printed circuit. It is furthermore already known to effect the supply of electricity to the constructional units through flat cables instead of through a usual cable harness. This flat cable is connected by means of a multiconnector to central connection points of the flexible printed circuits. Because of the necessary plug connections this type of electrical supply is still expensive, in spite of the use of the flexible printed circuit, which can be produced at low cost, and the flat cable, which is also cheap.

According to the present invention there is provided a wiring system for the supply of electricity to at least one constructional unit, which system comprises one or more said units which each include one or more electrical loads (such as a light bulb or instrument), and a flat cable having a plurality of metal conductors embedded in parallel in an insulating strip, wherein the flat cable extends into close proximity with the or each electrical load and electrically conductive connection between the or each load and the cable is effected by direct engagement of contact springs associated with the or each load on exposed portions of the respective metal conductors, whereby the or each load can be electrically energised.

If the flat cable only has a few metal conductors it is possible in most cases to conduct the flat cable to the side of the loads and to press it against a mounting plate holding the loads by means of the contact springs. If there are too many metal conductors the space conditions of the constructional unit can eventually prevent that.

Then, according to a further development of the invention, the flat cable is divided into at least two bunches of conductors which are positioned on opposite sides of the loads.

This allows a central arrangement of the loads in the constructional unit. In a particularly simple embodiment in order to form the bunches of conductors the flat cable is provided with a longitudinal slot to form the two bunches and the loads are arranged in this slot.

In a further embodiment of the invention in order to form the bunches of conductors the distance between two neighbouring metal conductors is arranged to be larger than the distance between the rest of the metal conductors in the respective bunches. Then the loads can be arranged in the part of the cable without metal conductors, and therefore in the area of the loads the insulating strip is provided with corresponding recesses.

In order to ensure that in the slotted cable embodiment the deformations arising when the bunches of conductors are forced apart do not exceed an admissible degree, and in order to ensure that in the spaced conductor embodiment the overall width of the flat cable does not become inadmissibly large, according to an advantageous development of the invention the respective inner metal conductor of a bunch of conductors is arranged to terminate adjacent a load.

Embodiments of the invention will now be described with reference to the accompanying drawings, in which: Figure 1 shows schematically a first embodiment of a wiring system for the electrical supply to a rear lamp of an automotive vehicle according to the present invention Figure 2 is a cross-section through the flat cable of Figure 1 beyond the rear lamp; Figure 3 shows a second embodiment of electrical supply according to the present invention, and Figure 4 is a cross-section through a rear lamp wiring system of the present invention.

In Figure 1 is shown a rear lamp 10 which comprises a constructional unit in which a flasher lamp 11, a stop and tail lamp 12 as well as a reversing lamp 13 are combined.

Electrical bulbs 14, 15 and 16 are the loads of this constructional unit. The current is supplied to these loads via a flat cable 20, which has several metal conductors 21 embedded in a common insulating strip 22 and which extends into close proximity with the loads.

The flat cable 20 is slotted in the longitudinal direction of the metal conductors, so that two bunches of conductors 23 and 24 are formed. These bunches of conductors 23 and 24 are arranged such that the electrical bulbs 14, 15 and 16 are located within the slot 25. The electrical connection to the bulbs can be simply effected by means of contact springs 26 associated with the bulbs contacting correspondingly exposed portions of the metal conductors. Expensive plug connections are therefore not necessary.

In the embodiment shown in Figure 3, the two bunches of conductors 23 and 24 are arranged on opposite sides of the electrical bulbs 14, 15 and 16 but in this embodiment the flat cable 20 is, however, not slotted but rather has a middle area 30 which does not contain metal conductors. Thus the distance between the two neighbouring metal conductors 21a and 21b is substantially larger than the distance between the metal conductors of either bunch and approximately corresponds to the size of the electrical bulbs. The bulbs are located in the area without metal conductors, in corresponding recesses 31 in the insulating strip. The conductive connection to the load is again effected through contact springs 26 associated with the bulb without a plug connection.

In Figure 4 is shown the flat cable 20 supported on a mounting plate 40 which is formed integrally with a reflector housing 41. The electrical bulb 14 is fitted by a bayonet fitting in a socket 42, on which the contact springs 26 associated with the bulb are engaged in well-known manner. Thus the electrical bulb 14 and the contact springs 26 by means of the socket 42 form a subassembly which can be inserted into the housing 41, whereby the contact springs 26 directly engage on the corresponding metal conductors 21 and thereby press the flat cable 20 against the mounting plate 40. This pressure serves to fix the flat cable in the housing, but additional fastening means in the shape of holding shoulders 43 (Figures 1 and 4) or fixing studs 45 (Figures 1 and 3) are provided, so that the flat cable is also held in longitudinal direction.

From Figure 1 can be seen that the inner metal conductor 21a terminates adjacent the electrical bulb 14. This metal conductor is not necessary for supplying further loads and can be cut off. The distance between the inner metal conductors of the bunches of conductors 23 and 24 can thus be made smaller, so that in the area of the slot the flat cable need not be forced apart too far.

In Figure 1 can furthermore be seen that the inner metal conductor 21b of the bunch of conductors 24 is connected to all the electrical bulbs 14, 15 and 16, thus serving as an earthing connection. Because the current load of this metal conductor is substantially higher than the current load of the rest of the metal conductors its cross-section would have to be enlarged. However in practice it has been shown that this can be avoided, if the metal conductor 21b is connected in an electrically conductive manner with the body of the vehicle directly outside the rear lamp. For this purpose a contact web can be provided which is indicated at 44.

Because the basic purpose of contact springs 26 is to provide protection against axial displacement of the sockets 42 which are attached to the housing by a bayonet fitting, an additional support 46 has to be injection moulded on the socket, if - as shown in Figure 3 - the contact springs 26 only engage the metal conductors of one bunch of conductors.

By the dash-dotted connection line between Figure 1 to 3 it is indicated that the flat cable 20 can be conducted to all constructional units of a vehicle as a ring main.

The flat cable can be attached to the surface of the vehicle body, and particularly at the points where the body walls have to be penetrated, the cable can be folded so that the metal conductors of the flat cable are superposed in a meander-shaped manner, and a square cross-section is created as shown in Figure 2. A clamp 50 holds the folded cable, which clamp 50 simultaneously serves as a fixing or insulating sleeve when the flat cable is conducted through corresponding recesses of the body wall parts of the vehicle.

The cable may be directed to the next constructional unit of the vehicle in the folded form with clamps 50 arranged at intervals to maintain the shape.

The present invention provides a substantially cheaper type of wiring system than the prior art since the flexible printed circuits of the prior art are replaced directly by a part of the flat cable, and the additional connecting means required between the flat cable and the flexible printed circuit are no longer necessary.

WHAT WE CLAIM IS: 1. A wiring system for the supply of electricity to at least one constructional unit, which system comprises one or more said units which each include one or more electrical loads (such as a light bulb or instrument), and a flat cable having a plurality of metal conductors embedded in parallel in an insulating strip, wherein the flat cable extends into close proximity with the or each electrical load and electrically conductive connection between the or each load and the cable is effected by direct engagement of contact springs associated with the or each load on exposed portions of the respective metal conductors, whereby the or each load can be electrically energised.

2. A wiring system as claimed in claim 1, wherein the flat cable is pressed against a mounting plate holding the or each load by the contact springs.

3. A wiring system as claimed in claim 1 or 2 wherein the flat cable is divided into two bunches of conductors which are arranged on opposite sides of the or each load.

4. A wiring system as claimed in claim 3, wherein the flat cable is slotted in the longitudinal direction in order to form the bunches of conductors.

5. A wiring system as claimed in claim 3 wherein for the formation of the bunches of conductors the distance between two neighbouring metal conductors is arranged to be larger than the distance between the rest of the metal conductors in the respective bunches.

6. A wiring system as claimed in claim 5, wherein the insulating strip is provided with recesses in the area of the or each load between the two neighbouring metal conductors.

7. A wiring system as claimed in any one of claims 3 to 6, wherein one of the metal conductors adjacent a load terminates at the load.

8. A wiring system as claimed in any one of claims 2 to 7, wherein the flat cable is detachably held on the mounting plate by fastening means.

9. A wiring system as claimed in any one of claims 2 to 8, wherein the or each load is an electrical bulb which is inserted from the side of support of the flat cable on the mounting plate through a recess in the mounting plate and engages with a bayonet fitting a respective socket element, the contact springs serving also as protection against axial displacement of the or each socket element.

10. A wiring system as claimed in claim 9, wherein when the contact springs necessary for electrical connection are not arranged symmetrically additional supports are provided for axial displacement protection.

11. A wiring system as claimed in any one of the preceding claims and for use in an automotive vehicle, wherein one of the metal conductors is common to a plurality of loads in a constructional unit and is connected in an electrically conductive manner with the body of the vehicle by a contact web adjacent the loads.

12. A wiring system as claimed in any one of the preceding claims, wherein outside of the constructional unit the flat cable is folded so that the metal conductors are superposed in meander-shaped manner and are held by clamps arranged at intervals along its length.

13. A wiring system for the rear lights of an automotive vehicle substantially as herein described with reference to Figures 1, 2 and 4 or Figures 2, 3 and 4 of the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. flat cable 20 can be conducted to all constructional units of a vehicle as a ring main. The flat cable can be attached to the surface of the vehicle body, and particularly at the points where the body walls have to be penetrated, the cable can be folded so that the metal conductors of the flat cable are superposed in a meander-shaped manner, and a square cross-section is created as shown in Figure 2. A clamp 50 holds the folded cable, which clamp 50 simultaneously serves as a fixing or insulating sleeve when the flat cable is conducted through corresponding recesses of the body wall parts of the vehicle. The cable may be directed to the next constructional unit of the vehicle in the folded form with clamps 50 arranged at intervals to maintain the shape. The present invention provides a substantially cheaper type of wiring system than the prior art since the flexible printed circuits of the prior art are replaced directly by a part of the flat cable, and the additional connecting means required between the flat cable and the flexible printed circuit are no longer necessary. WHAT WE CLAIM IS:

1. A wiring system for the supply of electricity to at least one constructional unit, which system comprises one or more said units which each include one or more electrical loads (such as a light bulb or instrument), and a flat cable having a plurality of metal conductors embedded in parallel in an insulating strip, wherein the flat cable extends into close proximity with the or each electrical load and electrically conductive connection between the or each load and the cable is effected by direct engagement of contact springs associated with the or each load on exposed portions of the respective metal conductors, whereby the or each load can be electrically energised.