WO2003066376A1

WO2003066376A1 - A vehicle accessory

Info

Publication number: WO2003066376A1
Application number: PCT/IB2002/005053
Authority: WO
Inventors: Elizabeth Mary Ward
Original assignee: Elizabeth Mary Ward
Priority date: 2002-02-04
Filing date: 2002-12-02
Publication date: 2003-08-14
Also published as: ZA200406969B; AU2002351063A1

Abstract

The invention provides a vehicle accessory for use between a towing vehicle (1) and a towed vehicle (2) to operate a lighting system of the towed vehicle in accordance with the lighting system of the towing vehicle's (1) which includes a transducer (21) to transmit a signal to a processor (105) when a monitored light of the lighting system is activated. The processor (105) being configured to control the towed vehicles lighting system in response to the signal from the transducer (21) such that the towed vehicle's lighting system operates synchronously with that of the towing vehicle. The transducer (21) is a Hall effect transducer which clips over the lighting system cables.

Description

A VEHICLE ACCESSORY

FIELD OF THE INVENTION

This invention relates to an accessory for vehicles, more particularly for towing and towed vehicles.

BACKGROUND TO THE INVENTION

When towing a vehicle, such as a trailer, it is necessary to connect the towing vehicle's lighting system to that of the towed vehicle such that the lighting system of both vehicles operate synchronously. At present this is achieved by providing an electrical socket connected to the lighting system on one of the vehicles and which receives any complementary plug connected to the lighting system of the other vehicle.

Such systems are fairly effective but do suffer the disadvantage that the socket and plug are relatively easily damaged and are susceptible to corrosion, especially in coastal areas. A further common problem is that the electrical cable to which the plug is secured is often damaged when caught between the vehicles or by dragging on a road surface.

Another problem when installing conventional monitoring systems in vehicles is that joining cables of the monitoring system to those of the lighting system often causes damage. The problem is pronounced in modern vehicles where thin cables tend to be used. Even more problematical are vehicles employing fibre technology to operate lights as the fibres cannot be monitored by conventional means.

In this specification "processor" and "cable" are to be given their widest meaning. The former shall include any means for receiving an input and providing an output based thereon. The later shall include wire or fibre used to carry electricity.

OBJECT OF THE INVENTION

It is an object of this invention to provide a vehicle accessory which will at least partially alleviate some of the abovementioned problems.

SUMMARY OF THE INVENTION

In accordance with this invention there is provided a vehicle accessory for use between a towing vehicle and a towed vehicle to operate a lighting system of the towed vehicle in accordance with the lighting system of the towing vehicle characterised in that the accessory comprises a transducer to transmit a signal to a processor when a monitored light of the lighting system is activated, the processor being configured to control the towed vehicle's lighting system in response to a signal from the transducer such that the towed vehicle's lighting system operates synchronously with that of the towing vehicle.

Further features of the invention provide for the towing vehicle's lighting system to be monitored by means of Hall effect transducers; for each Hall effect transducer to measure the magnetic field set up by current flowing in a cable or set of cables and for each Hall effect transducer to be secured to a cable or set of cables, preferably releasably clipped around a cable. Still further features of the invention provide for the processor to be a CPU (105) and includes a transmitter (20) to transmit the monitored signal to a receiver (30) connected to the towed vehicle's lighting system (8,9,10). A yet further feature of the invention provides for the transducer to monitor the taillights, brake lights and indicator lights of the towing vehicle's lighting system.

The invention also provides a vehicle including a processor for operating at least part of a towed vehicles lighting system synchronously with that of a towing vehicle characterised in that the processor is connected to at least some cables of the towing vehicle's lighting system by means of Hall effect transducers.

Further features of the invention provide for each Hall effect transducer to measure the magnetic field set up by current flowing in a cable; for each Hall effect transducer to be secured around a cable, preferably releasably clipped around a cable; and for the processor to include a transmitter as defined above.

The invention still further provides a method of monitoring at least some of a vehicle's lights which includes connecting a processor to cables of the lights using Hall effect transducers and monitoring the current flowing in each cable by measuring the magnetic field set up by current flowing in such cables.

BRIEF DESCRIPTION OF THE DRAWINGS

A preferred embodiment of a vehicle accessory according to this invention will be described, by way of example only, with reference to the accompanying drawings in which

Figure 1 is a perspective view of a motorcar and a trailer fitted with a vehicle accessory; Figure 2 shows a schematic wiring diagram; and

Figure 3 shows a split core transducer in position around a set of cables. DETAILED DESCRIPTION OF THE DRAWINGS

A motorcar (1) and trailer (2) are shown in Figure 1. The motorcar (1) has, in conventional fashion, a lighting system which includes taillights (4), brake lights (5) and indicator lights (6) (only the rear set are shown). The trailer (2) has a corresponding set of taillights (8), brake lights (9) and indicator lights (10). An accessory which includes a transmitter (20) and a receiver (30) is fitted to the motorcar (1 ) and trailer (2).

The transmitter (20) is secured in the motorcar (1) and connected to the lighting system to monitor the lights (4,5,6) by means of Hall effect transducers (21). As shown in Figure 3, each transducer (21) is secured around a set of cables (22) and measures the magnetic fields set up by a current flowing in the cables (22). The transducers (21) are releasably clipped over each set of cables (22) to facilitate fitment. This feature of the invention is of great benefit, especially in modern vehicles using fibre technology where the fibres cannot be connected to cables. Even where cables are used these cables are today generally thin and easily damaged by attempts to join other cables to them.

The receiver (30) is secured in the trailer (2) and is connected to the lights (8,9,10) by means of a plug (31) wired to the lights (8,9,10). The plug (31) is conventionally wired to the lights (8,9,10) at time of manufacture of the trailer (2) and fits in a complimentary socket (not shown) on the receiver (30).

A battery (32) provides a source of power for the receiver (30) and lights (8,9,10) and is charged by a dynamo (not shown) secured to the trailer (2) to run of one of the wheels (35). In use, when any of the vehicle's lights (4,5,6) are operated a signal is produced by the corresponding transducer (21) which in turn causes the transmitter (20) to emit a signal. When the latter signal is received by the receiver (30) it causes the corresponding light (8,9,10) to synchronously operate on the trailer (2). The accessory thus obviates the need for an electrical coupling between the motorcar (1) and trailer (2) in order to operate the lighting system of the trailer (2).

A transducer will be fitted to each of the left and right hand sets of cables for the towing vehicle, one of which will be the main feeder circuit and the other will be a branch harness.

The transducers measure the magnetic field set up by the currents in the different cables and, for example, the table set out below indicates the signals fed to the computer processor unit ("CPU").

LEFT SIDE RIGHT SIDE

Stop Lamps 42 + 21 Watt (Constant)

Tail Lamps 10 + 5 Watt (Constant)

Indicators LH 21 + 0 Watt (Intermittent)

RH 21 + 21 Watt (Intermittent)

Hazard lights 42 + 21 Watt (Intermittent)

The CPU analyses the data and turns "ON" the effected circuit. The change in load in the supply circuit is then checked to match the data supplied for lamp failure. The CPU can be self learning or programmed.

For a further understanding of the invention reference is made to Figures 2 and 3.

In Fig 2 the schematic wiring diagram shows one of a pair of split core Hall effect transducers (100) clipped around one set of brake (101), indicator (102), and side (103) light cables of a towing vehicle. These transducers (100) are connected to a signal conditioning unit (100A) connected to a power supply (104) and a CPU (105). The latter is connectable to the power supply (104) which is also connected to the output unit (106) for the transmitter-receiver assemblies connected to the trailer plug for the cables (101 A), (102A), (103A) corresponding to the towing vehicle brake (101), indicator (102) and side lights (103).

The output unit (106) is also connected to a lamp failure display unit (107) usually mounted on the towing vehicle instrument panel.

Fig 3 shows one set of three cables (101) (102) and (103) with a split ferrite core (108) around them.

It will be appreciated, however, that many other embodiments of a vehicle accessory exist which fall within the scope of the invention particularly as regards the configuration of the transmitter and receiver. For example, the CPU could be hardwired to the lighting system of the towed vehicle through the use of a plug and socket connection between the vehicles. The transducers may be used to monitor individual cables. Also, any convenient method can be used to provide a source of power to the towed vehicle. Both the transmitter and receiver can be configured to provide feedback on the lighting systems to the driver of a vehicle.

For example, the receiver could transmit a signal to the transmitter when a fused bulb is detected in the towed vehicle's lighting system and the transmitter could indicate this on a dedicated display screen in the cab of the towing vehicle. Furthermore, the accessory will preferably make use of coded signals to prevent the receiver responding to signals from similar transmitters fitted to other vehicles in its vicinity.

The system above described may also monitor additional trailer lights such as fog and/or reversing lamps. The invention also provides a processor connected to cables of the lighting system of a towing vehicle by means of Hall effect transducers. The processor could have a transmitter as described above or could provide a socket for receiving a conventional lighting system plug on a towed vehicle. As indicated above, the use of Hall effect transducers, especially transducers than can be clipped around a cable, greatly facilitates installation without the risk of damage to the lighting system. It will be understood that any suitable processor can be used.

Claims

1. A vehicle accessory for use between a towing vehicle (1) and a towed vehicle (2) to operate a lighting system of the towed vehicle (2) in accordance with the lighting system of the towing vehicle characterised in that the accessory comprises a transducer (21) to transmit a signal to a processor (105) when a monitored light of the lighting system (4,5,6) is activated, the processor (105) being configured to control the towed vehicle's lighting system (8,9,10) in response to the signal from the transducer (20) such that the towed vehicle's lighting system (8,9,10) operates synchronously with that of the towing vehicle.

2. A vehicle accessory as claimed in claim 1 characterised in that the transducer (21 ) is a Hall effect transducer.

3. A vehicle accessory as claimed in claim 2 characterised in that the transducer (21) is secured around cables (22) of the lighting system (4,5,6) to measure the magnetic field set up by current flowing in the towing vehicle's lighting system (4,5,6).

4. A vehicle accessory as claimed in claim 3 characterised in that the transducer is clipped around the cables (22) of the towing vehicle's lighting system.

5. A vehicle accessory as claimed in any one of the preceding claims in which the processor is a CPU (105) and includes a transmitter (20) to transmit the monitored signal to a receiver (30) connected to the towed vehicle's lighting system (8,9,10).

6. A vehicle accessory as claimed in claim 5 characterised in that the receiver (30) is directly connected to the towed vehicle's lighting system (8,9,10).

7. A vehicle accessory as claimed in claim 5 or 6 characterised in that the receiver (30) is connected to the lighting system by a socket providing a complementary fit for an existing plug (31) connected to the light system (8,9,10).

8. A vehicle accessory as claimed in any one of claims 5 to 7 characterised in that the transmitter (20) is connected to monitor the tail (4), brake (5) and indicator (6) lights of the towing vehicle.

9. A vehicle accessory as claimed in any one of the preceding claims characterised in that the transducer (100) is connected by clipping a split core (108) around the cables to measure the magnetic field set up by current flowing in the cables.

10. A method of monitoring at least some of a vehicle's lights which includes connecting a processor to cables of the lights using Hall effect transducers and monitoring the current flowing in each cable by measuring the magnetic field set up by current flowing in such cables

11. A vehicle accessory substantially as described and illustrated in the accompanying drawings.