GB2223366A

GB2223366A - Emergency braking warning system for vehicles

Info

Publication number: GB2223366A
Application number: GB8816503A
Authority: GB
Inventors: Nigel Mark Bovis
Original assignee: Individual
Current assignee: Individual
Priority date: 1988-07-12
Filing date: 1988-07-12
Publication date: 1990-04-04
Anticipated expiration: 2008-07-12
Also published as: GB2223366B; GB8816503D0

Abstract

An audio and/or visual warning is given when the braking force of the vehicle exceeds a predetermined value, e.g. in response to a gravity switch, a mechanical switch which detects dipping of the front suspension or a high pressure switch in the hydraulic braking circuit. The warning may take the form of the flashing of the normal brake lights or the lighting of a distinctive combination of normal lights. The flashing warning may be associated with the use of fog lamps. Alternatively, a separate illuminable display may be provided, eg. including wording such as "EMERGENCY BRAKING". The warning may disappear when the braking force falls below the predetermined value, or may be arranged to remain for a set period afterwards.

Description

VEHICULAR WARNING SYSTEM The present invention relates to a system for warning when a vehicle is undergoing emergency braking.

Motor vehicles powered by an internal-combustion engine, for example, cars, lorries and the like are fitted with rear lamps which are illuminated when force is applied to the brake pedal. However, this signal gives no indication to a following vehicle as to whether the brakes are being gently applied or the vehicle is undergoing emergency braking. In this latter instance, particularly in adverse weather conditions, the driver of the following vehicle often realises too late that the vehicle in front is stopping particularly quickly.

This problem can be particularly acute where a vehicle has to stop quickly in foggy conditions. In such conditions, the rear brake lamps are often not discernible at any great distance from the rear of the vehicle, and/or they may be obscured by the brilliance of some modern rear fog lamps.

The present invention seeks to provide a warning system which will increase. road safety in emergency stop conditions.

According to the present invention there is provided a system for warning when a vehicle is undergoing emergency braking, said system comprising warning means arranged upon actuation to signal that the vehicle is undergoing emergency braking, and means for actuating said warning means, said actuating means being responsive to a braking force and being arranged to actuate said warning means if said braking force exceeds a predetermined value.

The warning means may comprise an audible warning, or a visual display, or may include both audible and visual means. Preferably, the warning means is electrically operated and includes means for connection to an electrical supply. In a preferred embodiment, the warning means comprises an illuminable display, for example, having one or more electric lamps.

Generally, a system of the invention will be incorporated in a motor vehicle, for example, powered by an internal-combustion engine. Such motor vehicles are equipped with an electrical lighting system including an electric battery, and in a preferred embodiment the electric battery constitutes the electrical supply to which said electrically operated warning means is arranged to be connected.

It would be possible to arrange for said warning means to be constituted by one or more of the lamps already provided in the vehicle's electrical lighting system. For example, the warning could be given by flashing the normal brake lamps or by illuminating a distinctive combination of the lamps provided.

However, it is preferred that the warning means be comprised by a separate illuminable display.

Furthermore, this display preferably includes illuminable explanatory wording, for example "EMERGENCY BRAKING", so that the warning being conveyed is immediately evident.

It is intended that the warning means be sounded and/or illuminated only when the vehicle is being brought to a rapid stop, that is, that a braking force is being applied to the vehicle which exceeds a predetermined value. This braking force could be internally or externally applied. In this respect, said actuating means could be arranged to respond to a vehicle deceleration which is higher than a predetermined rate. For example, said actuating means could be responsive to a gravity switch carried by the vehicle and/or to a mechanical switch responsive to the dipping of the front suspension. However, in a preferred embodiment, said actuating means is arranged to respond to the braking force applied by the vehicle brakes.For example, where the braking system is hydraulic, said actuating means are arranged to respond to the pressure in the hydraulic braking circuit and to actuate said warning means when said pressure exceeds a predetermined value. In an embodiment, a high pressure switch has electrical contacts arranged to be closed in response to the occurrence of high pressure in the fluid in said hydraulic circuit. When closed, the contacts of the high pressure switch are arranged to connect the illuminable display to the vehicle battery to cause illumination of the display.

The illumination of the display is arranged to cease when the braking force is removed.

Additionally, and/or alternatively said warning means is constituted by one or more lamps arranged to be coupled to the electrical supply by way of a flasher unit. In an embodiment, said flasher unit is and by relay means, and wherein said relay means is energized by way of said actuating means. In this manner, if the braking force exceeds a predetermined value and said switch is in an on position, the flasher unit will cause the lamps to flash.

Preferably, the switch is associated with a fog lamp circuit such that the flashing warning is generated in fog conditions. Preferably, means are provided to maintain the relay means energized.

In a preferred embodiment, the lamps and their associated flasher unit are provided together with said illuminable display and its associated high pressure switch. The relay means is coupled to the electrical supply by way of the high pressure switch such that the relay means is energized only when high pressure fluid exists in the hydraulic braking circuit. However, means may be provided to hold said relay means energized such that said lamps continue to flash.

An embodiment of the present invention will hereinafter be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 shows schematically an hydraulic braking circuit for a vehicle including a high pressure switch, and Figure 2 shows a lighting circuit for a vehicle incorporating a warning system of the invention.

The braking circuit shown schematically in Figure 1 includes two hydraulically operated front brakes 2 and two hydraulically operated rear brakes 4. The front brakes 2 are connected by way of a fluid pipe 6 to a master cylinder 8 whilst the rear brakes 4 are connected by way of fluid pipes 10 and 12 to the master cylinder 8. In known manner, the brakes are applied by way of a brake pedal 14, the increase in fluid pressure in the pipes 6, 10 and 12 caused by the application of force to the brake pedal 14 and the consequent operation of the master cylinder 8 being transmitted to slave cylinders (not shown) which apply the brakes 2 and 4. A pressure switch 16 is incorporated in the hydraulic circuit.This switch comprises normally open electrical contacts which are closed when fluid pressure in excess of a predetermined value is applied to the pressure switch 16 by the hydraulic braking circuit. This pressure switch 16 controls the illumination of rear brake lamps on the vehicle. Thus, in conventional manner, when the brakes 2, 4 are applied by operation of the brake pedal 14, the rear brake lamps are illuminated.

Of course, the fluid pressure needed to close the contacts of the switch 16 is chosen such that the brake lamps are illuminated only when the brake pedal is operated.

A further pressure switch 18 is also incorporated in the hydraulic braking circuit. This switch 18 similarly comprises normally open electrical contacts which are arranged to be closed upon application to the switch 18 of fluid pressure in excess of a predetermined value. However, the fluid pressure required to close the contacts of the switch 18 is substantially greater than that required to close the switch 16 such that the pressure switch 18 is responsive only to braking forces applied to the brake pedal 14 which exceed a predetermined value.

Figure 2 shows schematically the lighting circuit for the vehicle having the braking circuit of Figure 1. At its front the vehicle is provided with a pair of side lamps 20 which are connected together in parallel and in parallel to a pair of rear side lamps 21. The side lamps 20, 21 are connected by way of contacts "A" of an electrical switch 24 to a vehicle battery 26. The vehicle is also provided at its front with a pair of dipped head lamps 22 whi.ch are connected by way of contacts "B" of the switch 24 to the battery 26. Similarly, a pair of front main beam head lamps 28 are connectible by contacts "C" of the switch 24 to the battery 26. In known manner, the switch 24 is arranged such that the contacts "A" remain closed when contacts "B" or "C" are closed.

It will be seen from Figure 2 that the electrical contacts of the pressure switch 16 of the braking circuit control the connection of the battery 26 to a pair of parallel rear brake lamps 30. In a similar manner, the contacts of the high pressure switch 18 control the application of the electrical supply to a visual display generally indicated at 32.

In the embodiment illustrated, this display 32 comprises a lamp housing having a reflector, preferably red in colour, on which the words "EMERGENCY BRAKING" are provided. A pair of bulbs 34 are housed within the housing such that illumination of the bulbs 34 illuminates the reflector and the legend written thereon. It will therefore be appreciated that closing the contacts of the high pressure switch 18 will cause illumination of the display 32 and hence of the written warning thereon.

The display 32 is preferably affixed at a prominent location on the rear of the vehicle.

During normal braking, the fluid pressure in the hydraulic braking system will not be sufficient to close the contacts of the high pressure switch 18.

However, the application of a hard braking force, as occurs under emergency conditions, will increase the pressure in the hydraulic circuit such that the high pressure switch 18 will respond and thereby cause the display 32 to be illuminated. Of course, as the pressure in the braking circuit decreases, the electrical supply to the display 32 will be switched off by opening of the contacts of the high pressure switch 18.

The vehicle lighting system of Figure 2 also includes a pair of rear fog lamps 36 connected together in parallel and to the battery 26 by way of a fog lamp switch 38 and the contacts "B" of the light switch 24. It will therefore be appreciated that the front dipped head lamps 22 have to be switched on by way of the switch 24 before the fog lamps 36 can be illuminated.

It will also be seen that the fog lamp switch 38 is a double ganged switch, the contacts "D" thereof controlling the illumination of the fog lamps 36 whilst the contacts "E" thereof control a path from the contacts of the high pressure switch 18 to a relay 40. It will be appreciated that if the contacts "D" and "E" of the fog lamp switch 38 are closed, closing the contacts of the high pressure brake switch 18 will not only illuminate the display 32 but will also cause current to flow through and energise the relay 40.

The relay 40 has associated, normally open contacts "F" which are closed upon energisation of the relay 40 and thereby supply power to a series combination of a flasher unit 44 and a further relay 46. Once the relay 40 has been energised and has closed its contacts "F" a current path is provided from the battery 26 by way of contacts "D" of the fog lamp switch 38 to the contacts "F" which maintains the contacts "F" closed while ever there is current flow.

It will be seen that the flasher unit 44 and the further relay 46 act to apply current alternately to a pair of emergency fog warning lamps 48. This causes these two lamps 48 to flash on and off alternately.

Thus, in foggy conditions in which the rear fog lamps 36 have been switched on by way of the fog lamp switch 38, emergency braking to which the high presure switch 18 is responsive causes the emergency fog lamps 48 to be flashed on and off alternately. Release of the brake pedal and subsequent opening of the contacts of the switch 18 does not stop the lamps 48 flashing, although, as previously, the display 32 will be extinguished. The flashing of lamps 48 is made apparent to the driver of the vehicle by way of a warning lamp 42 provided on the vehicle dashboard and connected to the flasher unit 44.

The flashing of the lamps 48 is stopped by switching off the fog lamp switch 38. This removes the current from the contacts "F" of relay 40 which thereby resume their normally open position.

Switching the fog lamp switch 38 on again illuminates the rear fog lamps 36 but does not actuate the emergency fog lamps 48 unless emergency braking once again occurs. This means, that should the vehicle be involved in an accident, for example in which the vehicle driver becomes unconscious, the flashing lamps 48 will remain flashing to signal the emergency condition to following drivers.

It will be appreciated that modifications or variations to the invention can be made. For example, if the braking circuit is a dual hydraulic circuit twin high pressure switches could be provided, operation of either or both being chosen as necessary to illuminate the warning display.

Although it is particularly convenient to use the pressure in the hydraulic braking system to signal that emergency braking has taken place, other means of responding to such braking can be utilised. For example, the vehicle could be fitted with a gravity switch responsive to excessive deceleration of the vehicle.

In the particular embodiment described and illustrated, the high pressure switch responsive to the braking force is arranged to actuate a visual display affixed to the rear of the vehicle.

Additionally and/or alternatively, the brake switch could be arranged to actuate an audible warning and of course the exact construction and location of the audible and/or visual warning can be chosen as required. For example, a flashing visual warning could be provided. Similarly, the nature of the warning actuable when the fog lights are on can also be chosen as required. Of course, in all cases, it is important that the warning be immediately discernible and understandable to other road users.

Claims

1. A vehicular warning system for warning when a vehicle is undergoing emergency braking, said system comprising warning means arranged upon actuation to signal that the vehicle is undergoing emergency braking, and means for actuating said warning means, said actuating means being responsive to a braking force and being arranged to actuate said warning means if said braking force exceeds a predetermined value.

2. A warning system as claimed in Claim 1, wherein said warning means is electrically operated and includes means for connection to an electrical supply.

3. A warning system as claimed in Claim 2, wherein said warning means comprises an illuminable display.

4. A warning system as claimed in Claim 3, wherein said warning means comprises one or more lamps, and a flasher unit coupled to said connection means for the electrical supply.

5. A warning system as claimed in Claim 4, wherein said flasher unit is coupled to said connection means by way of a switch and by relay means.

6. A motor vehicle incorporating a warning system as.

claimed in any preceding claim, the motor vehicle having an electrical lighting system including an electric battery, and said warning means being electrically operated, and wherein said electric battery constitutes an electrical supply to which said warning means is arranged to be connected.

7. A motor vehicle as claimed in Claim 6, said warning means is constituted by one or more of the lamps provided in the vehicle's electrical lighting system.

8. A motor vehicle as claimed in Claim 6, wherein said warning means comprises a separate illuminable display.

9. A motor vehicle as claimed in Claim 8, wherein said illuminable display comprises illuminable explanatory wording.

10. A motor vehicle as claimed in any of Claims 6 to 9, wherein said actuating means is responsive to a braking force applied to the vehicle which exceeds a predetermined value.

11. A motor vehicle as claimed in Claim 10, wherein said actuating means is arranged to respond to a vehicle deceleration which is higher than a predetermined rate.

12. A motor vehicle as claimed in Claim 10, wherein said actuating means is arranged to respond to the braking force applied by vehicle brakes.

13. A motor vehicle as claimed in Claim 12, having an hydraulic braking circuit, and wherein said actuating means are arranged to respond to the pressure in the hydraulic braking circuit and to actuate said warning means when said pressure exceeds a predetermined value.

14. A motor vehicle as claimed in Claim 13, wherein a high pressure switch having electrical contacts is arranged to be closed in response to the occurrence of high pressure in the fluid in said hydraulic braking circuit, and when closed, the contacts of said high pressure switch are arranged to connect said warning means to the vehicle battery to cause actuation of said warning means.

15. A motor vehicle as claimed in Claim 14, wherein actuation of said warning means is arranged to cease when the braking force is removed.

16. A motor vehicle as claimed in any of Claims 6 to 15, wherein said warning means is constituted by one or more lamps arranged to be coupled to the electrical supply by way of a flasher unit, said flasher unit being coupled to the electrical supply by way of a switch and by relay means, and wherein said relay means is energized by way of said actuating means.

17. A motor vehicle as claimed in Claim 16, wherein said switch is associated with a fog lamp circuit such that a flashing warning is generated in fog conditions.

18. A motor vehicle as claimed in Claim 16 or 17, wherein the lamps and their associated flasher unit are provided together with warning means comprised of a separate illuminable display, and wherein the vehicle has an hydraulic braking circuit, and said actuating means comprises a high pressure switch having electrical contacts arranged to be closed in response to the occurrence of high pressure in the fluid in said braking circuit, and when closed, the contacts of said high pressure switch being arranged to connect said illuminable display to the vehicle battery to cause illumination of said display.

19. A motor vehicle as claimed in Claim 18, wherein said relay means is coupled to the electrical supply by way of the high pressure switch such that the relay means is energized only when high pressure fluid exists in the hydraulic braking circuit, and wherein means are provided to hold said relay means energized such that said lamps continue to flash.

20. A vehicular warning system substantially as hereinbefore described with reference to the accompanying drawings.

21. A motor vehicle incorporating a warning system substantially as hereinbefore described with reference to the accompanying drawings.