GB2302463A

GB2302463A - Speed or deceleration responsive warning system for vehicles

Info

Publication number: GB2302463A
Application number: GB9512438A
Authority: GB
Inventors: Harry Laughton
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-06-19
Filing date: 1995-06-19
Publication date: 1997-01-15
Also published as: GB9512438D0

Abstract

The warning system may produce a signal to indicate a change in vehicle speed to or below a predetermined speed. The predetermined speed may be 30 mph, but may be adjustable. The warning signal may be produced by comparing a signal from an electronic speedometer with a reference. Alternatively, a warning signal may be produced when vehicle deceleration exceeds a certain level. Deceleration rate may be computed by sampling the speedometer signal at predetermined intervals, or a deceleration sensor in the form of a pendulum 1 carrying a mercury switch may be used. The signal produced in response to speed or deceleration may cause the hazard warning lights to be activated or may cause an increase in brake light intensity. Isolating means may be provided for cancelling operation of the warning system under predetermined conditions. Override means may enable manual deactivation of the warning system.

Description

WARNING SYSTEMS This invention relates to warning systems. and in particular warning systems for motor vehicles.

Existing motor vehicles are provided with various warning systems which serve to alert other drivers as to the progress of the vehicle. The rear of most if not all motor vehicles are provided with red lights which become illuminated as soon as the driver exerts a pressure on the brake pedal of the vehicle. When illuminated. these lights serve to warn other drivers that the vehicle may be slowing down.

Many vehicles are provided with hazard warning lights which can be switched on by the driver when desired. Such warning lights are provided in addition to the brake warning lights. Hazard warning lights are coloured yellow and flash on and off so as to warn drivers of an impending hazard. These lights tend not to be activated by the driver until he has reached the hazard and his vehicle is stationary.

Conventional motor vehicles of this type have the disadvantage that the brake warning lights do not in themselves impart any useful information for other drivers other than warning them that the driver in front may be slowing down. Certainly, there is no indication as to the approximate speed of the vehicle.

This problem is particularly evident on motorways and the like where vehicles move at speeds of 70 mph or more. As soon as a driver sees the red brake warning lights of the vehicle in front. he is required to guess at the proposed intentions of the driver of that vehicle. For example, the driver in front may simply be resting his foot on the brake pedal thereby causing the brake lights to illuminate without slowing the vehicle down. Alternatively. the driver in front may simply be slowing down, but not to a sufficient extent to induce the following driver to take any evasive action.

Another possibility is that the driver in front with the illuminated brake warning lights may be intending to stop rapidly and may have already reached a slow speed with respect to the following vehicles. In this case, the drivers of the following vehicles will not know until they are relatively close to the vehicle in front that the vehicle in front is moving relatively slowly and so the following driver must then act quickly by braking hard so as to decelerate rapidly.

Naturally, rapid deceleration, particularly in wet whether, can lead to collisions involving many vehicles. Accidents of this type are not infrequent on motorways and can involve the loss of lives.

It is an aim of the present invention to provide a warning system which alleviates the aforementioned difficulties.

According to the present invention, there is provided a warning system for motor vehicles comprising detection means for detecting the speed of the vehicle and for generating a signal when the speed of the vehicle is reduced to or falls below a predetermined speed, which signal can be used for indicating the change in vehicle speed to or below said predetermined level.

In a particular embodiment of the invention. the signal is linked to the rear hazard warning lights of the vehicle which are activated when the speed of the vehicle falls below said predetermined level.

Activation of the hazard warning lights occurs in addition to the conventional activation of the rear brake warning lights.

It is conceivable that the signal may activate other forms of warning1 for example by increasing the intensity of the brake warning lights.

Embodiments of the present invention have the advantage that the driver of the vehicle can direct his full attention to controlling his vehicle while the vehicle can signal to other drivers that the vehicle speed has fallen below a predetermined level.

Embodiments of the invention would be particularly useful for motor vehicles on motorways since activation of, for example, the hazard warning lights would serve to indicate, to the drivers of relatively fast moving vehicles who are relatively distant from the vehicle in front. the need for them to take action to reduce their speed to a level comparable with that of the relatively slow speed of the vehicle in front.

It can readily be seen that embodiments of the invention can serve to give drivers extra time to slow their vehicles before reaching a hazard.

Embodiments of the present invention may be arranged so that the signal is generated when the speed of the vehicle falls below 30 mph.

As soon as a driver sees the hazard warning lights.

he can readily deduce that the vehicle in front is moving at say 30 mph or less and he can decide immediately what action to take to avoid a collision while being relatively distant from the vehicle.

Embodiments of the present invention are particularly useful for use in vehicles at night since it is more difficult at that time to assess the speed of vehicles in front.

Embodiments of the present invention may comprise isolating means for cancelling operation of the warning system under predetermined conditions. Alternatively, an override means1 which may be a switch. may be provided for enabling manual deactivation of the warning system. Speed variation means may be provided for varying the predetermined speed at which the warning system comes into operation.

According to a further aspect of the present invention, there is provided a warning system for motor vehicles comprising detection means for detecting deceleration of the vehicle and for generating a signal which indicates when the deceleration exceeds a predetermined value.

Embodiments according to this further aspect of the present invention may be linked to the rear hazard warning lights of the vehicle which are activated when the deceleration exceeds the predetermined value.

Conceivably, the signal may activate other forms of warning, for example by increasing the intensity of the brake warning lights.

As with embodiments of the invention for determining when the speed is reduced to or falls below a predetermined level, embodiments according to this further aspect have the advantage that the driver can direct his full attention to controlling the vehicle while the vehicle can signal to other drivers a sudden and hard deceleration.

Signalling deceleration in this way would be particularly useful on motorways since activation of, for example, the hazard warning lights would serve to indicate to the drivers of relatively fast moving vehicles of the need for them to take action to reduce their speed owing to a hazard realised by the driver of the decelerating vehicle.

Embodiments of this further aspect of the invention have advantages which correspond to those of the first aspect of the invention.

Embodiments of the further aspect of the present invention may comprise isolating means in a manner corresponding to that of embodiments of the first aspect of the invention.

According to the present invention there is yet further provided a motor vehicle comprising either of the warning systems as defined above.

The invention will now be described by way of example with reference to a specific example described hereinbelow, and with reference to the accompanying drawings, in which: Figure 1 illustrates in block form an alternative implementation of the invention; and Figure 2 illustrates a device for detecting deceleration.

An embodiment of the invention may comprise a computer card having an appropriate control circuitry mounted thereon. The control circuitry may be in the form of semiconductor chips, the card having connection terminals for connection to the wiring of an existing vehicle.

In the event that the existing vehicle has an electronic speedometer, the signal supplied to the speedometer can also be supplied to one of the terminals of the computer card. This signal, when received by the computer card, can be fed to a comparator which compares the speed of the vehicle with the predetermined speed stored in a memory in a semiconductor chip of the card.

The comparator may be operative for generating a signal when the signal indicating the speed of the vehicle is equal to or less than the predetermined value1 which signal can then be passed to a switch1 one terminal of which is connected to the gating circuit and the other is connected to another terminal of the card which another terminal is coupled to the hazard warning lights.

Various forms of circuitry for performing the invention would be readily apparent to the skilled man in the art.

Figure 1 illustrates a block diagram of an embodiment of the invention. In this embodiment, command data comprises signals which determine the operation of the field device. A solid state memory or set up switches is/are provided for momentarily storing input data or for buffering the data. This data is processed for achieving the desired actions. Processor 1 operates in accordance with the stored program. The Processor 2 generally switches the command data to match the characteristics of the field device.

Further, modifications may be made to the afore-described arrangements. for example, programming means may be provided for varying the value of the predetermined speed stored in the memory. An additional switch may be provided enabling manual commissioning or decommissioning of the warning system.

It would be readily apparent to the skilled man in the art that the embodiments described above could be modified to generate the warning signal when the vehicle deceleration exceeds a predetermined level in accordance with the further aspect of the present invention.

For example, the signal supplied to the speedometer could be sampled at regular intervals (i.e. every 0.1 second). The change in speed between successive intervals, and hence deceleration, can be computed by subtraction methods. The value of the deceleration computed can be fed to a comparator which compares the measured deceleration with the reference predetermined level. When the deceleration exceeds the predetermined value, the comparator generates a signal which can be passed to a switch for switching on the hazard warning lights.

When the computed deceleration falls below the predetermined level, the warning lights may be switched off automatically.

In alternative embodiments, an inertial may be provided for switching on the hazard warning lights when the deceleration exceeds a predetermined level.

In Figure 2. an inertial switch 1, has a pendulum 2 at one end, and a glass tube 3 at the other end. The pendulum is fixed to the vehicle at an axis 4 which is perpendicular to the direction of movement of the vehicle.

When the vehicle is stationary or is moving at constant speed1 the pendulum is in an upright position as indicated in Figure 2. When the vehicle accelerates and moves from left to right in Figure 2, the pendulum swings as indicated on the right-hand side of Figure 2.

When the vehicle decelerates, the pendulum swings as indicated on the left-hand side of Figure 2.

The glass tube 3 comprises a mercury contact switch having contacts 5 and 6 which can be connected to one another by mercury 7. The contacts 5 and 6 are connected to the hazard warning lights (not shown) of the vehicle. As can be seen from Figure 2. when the vehicle decelerates, the mercury 7 is caused to connect the contacts 5 and 6 thereby switching on the hazard warning lights. On the other hand, when the vehicle accelerates, the mercury moves to the other end of the glass tube 3 thereby disconnecting the contacts 5 and 6 and switching off the hazard warning lights. The pendulum inertial switch as described above can be housed in an enclosed box or container at any convenient point within the vehicle.

Claims

CLAIMS:

1. A warning system for a motor vehicle comprising detection means for detecting the speed of the vehicle and for generating a signal when the speed of the vehicle is reduced to or falls below a predetermined speed, which signal can be used for indicating the change in vehicle speed to or below the said predetermined level.

2. A warning system according to Claim 1, wherein the signal is linked to rear hazard warning lights of the vehicle, which are activated when the speed of the vehicle falls below the said predetermined level.

3 A warning system according to Claim 1 or 2, wherein the signal causes an increase in the intensity of brake warning lights of the vehicle.

4. A warning system according to any preceding claim, wherein the said predetermined speed is 30 mph.

5. A warning system according to any preceding claim, further comprising isolating means for cancelling operation of the warning system under a predetermined condition.

6. A warning system according to any preceding claim, comprising override means for enabling manual deactivation of the warning system.

7. A warning system according to any preceding claim, comprising speed variation means for varying the said predetermined speed at which the warning system comes into operation.

8. A warning system for a motor vehicle, comprising detection means for detecting deceleration of the vehicle and for generating a signal which indicates when the deceleration exceeds a predetermined value.

9. A warning system according to Claim 8, wherein the signal is linked to rear hazard warning lights of the vehicle, which are activated when the deceleration of the vehicle exceeds a predetermined value.

10. A warning system according to Claim 8 or 9, wherein the signal causes an increase in intensity of brake warning lights of the vehicle.

11. A warning system according to any one of Claims 8 to 10, further comprising isolating means for cancelling operation of the warning system under a predetermined condition.

12. A warning system according to any one of Claims 8 to ii, comprising override means for enabling manual deactivation of the warning system.

13. A warning system substantially as hereinbefore described with reference to Figure 1 or Figure 2 of the accompanying drawings.

14. A vehicle comprising a warning system according to any one of Claims 1 to 13.