GB2190553A - Motor vehicle rear lighting systems - Google Patents

Abstract

When rear stop lights 15 and the rear fog lights 14 are operated together, one of them, preferably the fog lights are caused to flash. If a fog light switch 40 is closed, a relay 12 is operated so that the fog lights 14 are energised over contact sets 32 and 24 with either a continuous signal from a line 16 or an intermittent signal from a line 38 in dependence respectively on whether a relay 10 is energised or de-energised. Closure of brake switch 17 de-energises the relay 10. A delay circuit (60), (Figure 4), and a further relay (64) may cause the fog lights 14 to be energised continuously for a predetermined period on operation of the left or right flashing direction indicators, following which period the state of the fog lights is again dependent on the states of switches 17,40. <IMAGE>

Description

SPECIFICATION Motor vehicle rear lighting systems This invention relates to an improved rear lighting system for vehicles, especially motor vehicles.

Motorvehicle rear lighting systems generally comprise tail lights, rear stop lights and rearfog lamps. Tail lights are designed to enable the vehicle to be seen in darkness or in poor weather conditions and continuously emit a constantglow of light of relatively low intensity. Rear stop lights are activated automaticallywhenthe brakesofthevehicleare applied and continuously emit light of relatively high intensity in order to indicate when the vehicle is in the course of braking. Rearfog lamps are generally used in particularly poor weather conditions such as in fog orin heavy rain ad continuously emit light of relatively high intensity enabling the vehicle to be more easily seen in conditions of poor visibility.Rear stop lights usually have red lens covers, whilstfog lights also usually have red lens covers, in orderto assist in distinguishing one from the other, and usuallythe lenses of the same colour are used forthe stop lights and the fog lights.

A disadvantage of the present rear lighting system is that rear fog lights and rear stop lights are often located in close proximity and emit light of the same or of a similar intensity so that in some conditions, even if different coloured lenses are used, it is difficu It to distinguish between the lights.

Accordingly, when tail lights and rear fog lights are in use, it is not always immediately apparent to the driver of a following vehicle that the rear stop lights of the vehicle in front have been activated and the driver may delay in braking thereby causing his vehicle to collide with the vehicle in front. Research shows that when vehicles are travelling at high speed and in poor weather conditions, the driver of a following vehicle must react within a fraction of a second of the rear stop lights of the vehicle in front being activated in orderto enable him to stop in time to avoid a collision. It will be appreciated therefore that the slightest delay in reaction time caused as a result of a driverfailing to distinguish between the rear stop lights and rear fog lights of the vehicle in front may result in a collision.

The present invention in one embodiment enables rearstop lights and rearfog lights to be easily distinguishable when illuminated at the same time thereby enabling drivers offollowing vehicles to react quickly to the application ofthe rear brakes of the vehicle in front.

According to the present invention there is provided a vehicle lighting circuit comprising: a) first rear lights for performing a continuously illuminated function, and b) second rear lights for performing a continuously illuminated function, the improvement comprising a control circuit comprising an output supplying a voltage signal which varies cyclically and means for coupling cyclic voltage signal to one of the first and second rear lights whilst in a predetermined condition so asto override the continuously illuminated function of said one ofthe first and second rear lights so that said one of the first and second rear lights will emit intermittent illumination.

Embodiments of the invention will now be described by way of example with reference to the accompanying drawings in which: Figures 1,2 and 3 show a circuit diagram of a vehicle rear lighting system according to the invention and in three respective conditions of operation; and Figure 4is a view similarto Figure 3, but showing a second embodimentofthe invention.

Referring to Figures 1,2 and 3 a control circuit embodied in the vehicle lighting circuit is shown.

The circuit comprises basically two relays or solenoids 10 and 12 which operate in conjunction with one another in orderto ensure that in this example the rear fog lights 14willflash intermittently upon the establishment of a condition in which the rearfog lights areturned on, and also the rear stop lights 1 5are on. As is well known, rear stop lights are illuminated when the brake pedal is depressed.

Figure 1 shows the condition in which both the rearfog lights 14 and the rear stop lights 15 are off.

The rearfog light circuit includes the lights 14and these are supplied with power from a line 16 coupled to the electrical circuitry of the vehicle sothat normally a steady electric potential is applied thereon when a fog light switch 40 is closed. Line 16 is coupled to the coil of solenoid 10 through line 18 and the output of the coil, line 20, leads through diode 21 to the brake stop light circuit 22.

Line 16 also couples through a two-position relay switch 24the moving contact 26 of which is coupled through line 28 to second normally open contacts 32 ofthe solenoid 12. The output line 34 from contacts 32 leads to lights 14which at the output end are earthed at 36 as shown.

The contact switch 24 receives an input on line 38 from the vehicle flasher control terminal which is connected to either the right or left flasher lightwhen the flasher switch is appropriately positioned, and on which control terminal there is always available a pulsing intermittent output.

The brake circuit 22 conditions the state of the coil of the solenoid lOso that when the rear stop lights are off, and the rear fog lamp switch 40 is closed,the coil orthe solenoid 10 is energised in that asmall currentflows through the switch 40, the coil of solenoid 10, diode 21 and through the brake lights 15; this current is insufficientto illuminate lights 15.

When solenoid 10 is so energised, its curvature pulls contact 26 downwards. On the other hand, when the brake switch 17 is closed, the output side of diode 21 is raised in potential and if the rear fog light switch 40 is closed, the potential across the coil of solenoid 10 is reduced to zero the coil is de-energised and the contact 26 returnsto the normal non-energised position, which is the position shown in Figure 1.At the same time the brake lights are illuminated.

The operation of the circuit is as follows. In the Figure 1 position, both the rear fog lights and the rear stop lights are off. The flasher unit output on line 38 is applied through contact switch 24to contact 26 and line 28, but contacts 32 are open and therefore the intermittent signal is not applied to the rearfog lights.

When the rearfog light switch 40 is closed, butthe brake circuit 22 is not operative, the condition shown in Figure 2 prevaiis. In this condition, the coil or solenoid 10 is energised sothatthecontact26 is pulled to the lower position as shown in Figure 2 in which case the constant potential applied on line 16 is applied to contact 26 and line 28, and in addition the same potential is appliedthroug h line 44 to the coil of solenoid 12 energising same and clamp contacts 32. The said potential is therefore applied on line 34 and to the lights l4which are illuminated.

With the rearfog lights on, and with the application ofthe brakes atthe same time, the rear stop lights are illuminated by the closing of rear stop light switch 17 and bythe conditioning of circuit 22 the coil or solenoid 10 is de-energised which results in contact 26 moving backto the upwards position as shown in Figure 3 and also in Figure 1. Therefore, the intermittent output on line 38 is applied through contact 26, line 28, the still closed contacts 32, line 34 and to the lights 14which therefore flash intermittently whereby the driver of a vehicle traveiling behind will be warned of some possible emergency giving rise to the application of the brakes bythe driver of the vehicle.

Referring to the embodiment of the invention illustrated in Figure 4, parts already described in relation to Figures 1 to 3 have the same reference numerals and are not described further. In the arrangement of Figure 4, the vehicle indicatorflasher circuit is further connected to the control circuit in that indicator signal lines 50 and 52 couple through diodes 54 and 56 are connected by a line 58to a delay unit 60 which is of the "fade away" type. Additionally line 58 is coupled by line 62 to a third relay or solenoid 64, the normally open contacts 66 of which are connected from earth via line 68 to line 20. When there is a signal therefore on either flasher line 50 or 52, the resulting potential on line 58 is applied through solenoid 64 energising same and closing contacts 66.This results through line 68 in the coupling line 20 to earth whereby the solenoid 10 can be energised through the delay unit 60 even if the fog light switch 40 is open, so that contact 26 will be kept in the condition shown in Figure 4, preventing the transmission of the flasher output signal from being applied as described above to the rearfog lights 14.

This condition pervails only for a predetermined period set bythe delay unit60 and attheendofthat period, the output signal from delay unit 60 is lost and solenoid 10 is de-energised unless the switch 40 is closed in which case the solenoid 10 will remain energised as will solenoid 12, and if the brake stop lights are applied, solenoid 1 twill be de-energised as described above causing contact 26 to move to the position connecting line 38 to line 28 and hence to the rear fog lights which are caused to flash.

If switch 40 is open, then solenoid 12 is only energised during the period that is set by the delay unit 60 and at the end ofthat period solenoid 12 will be de-energised and therefore any de-energisation of the solenoid 10 will not permitthe signal on line 38 to be applied to the rear stop lights 14.

In afurtherembodimentofthe invention, the control circuit operates in such a mannerthatthe rear stop lights are caused to flash intermittently when the rear fog lights are turned on at the same time as the rear stop lightsareon.

Claims (9)

1. In avehicle lighting circuit comprising: a) first rear lightsforperforming a continuously illuminated function, and b) second rear lights for performing a continuously illuminated function, the improvement comprising a control circuit comprising an output supplying a voltage signal which varies cyclicaliy and means for coupling cyclic voltage signal to one of the first and second rear lights whilst in a predetermined condition so asto override the continuously illuminated function of said one of the first and second rear lights so that said one of the first and second rear lights will emit intermittent illumination.

2. The improvement according to claim 1, wherein said first rear lights are rear stop lights actuable on thefirstfunction upon application of the brakes of the vehicle.

3. The improvement according to claim 1 or 2, wherein the said second rear lights are rearfog lights of the vehicle suitable in thefirstformation by positioning of a fog light switch of the vehicle.

4. The improvement according to any of claims 1 to 4, wherein the said means for coupling comprises a first relay engageable by setting the second rear lights to operate in the continuously illuminated function, said second relay having contacts positionable when the relay is energised to disconnect the cyclic voltage signal from the second rear lights and when de-energised to connect two said cyclic voltage signal to the second rear lights, a diode preventing energisation of the first relay ofthefirst lights are in the continuous illumination function, and a second relay energisable by setting the second lightsto operate in thecontinuous illumination function and having contacts in the connection between the output supplying said cyclic voltage signal, and the said second rear lights which contacts are closed when the said second relay is energised and open when the second relay is de-energised.

5. The improvement according to claims 1,2 or3, wherein the said second lights are arranged to emit intermittent illumination in the predetermined condition when the first and second lights are setto operate in the first and second conditions simultaneously.

6. The improvement according to any of claims 1 to 5, including third rearlightmeansforperforming an intermittently illuminated direction indicating function, and said control circuit including a means preventing connection of said cyclic voltage signal to said first or second rear lights when in said predetermined condition when said third rear lights are set to operate in said direction indicating function.

7. The improvement according to claim 6, wherein there is a delay means controlling the length oftimesaid means preventing is operative so that when the first and second lights are in said predetermined condition, and said third lights are set to the direction indicating function, the said cyclic voltage signal will be prevented from being applied to the first or second lights only for a predetermined delay period.

8. The improvement according to Claim 4 or 5, including third rear light means for performing an intermittently illuminated direction indicating function, and said control circuit including a third relay which is connected to be energised when said third lights are set to the direction indicating function, said third relay having contacts monitoring the first relay energised when the second rear lights are set to operate in the continuous illumination function.

9. In a vehicle having a lighting circuit the improvement substantially as hereinbefore described with reference to the accompanying drawings.