GB2281887A - A vehicle anti-theft device - Google Patents

Abstract

A vehicle with an automatic gear box includes a device which automatically renders the vehicle undrivable. The device acts to open relays in the ignition and starter motor circuits and mechanically locks the transmission in "park". In order to reactivate the vehicle, a code must be entered on a keypad and the key inserted in the ignition. <IMAGE>

Description

A VEHICLE ANTI-THEFT DEVICE The invention relates to a vehicle anti-theft device.

A number of vehicle anti-theft devices are known. A car may include a steering lock which operates when the engine is turned off and the steering wheel is turned to its furthest extent. A lock is known for a car which fits over the gear lever and handbrake.

Various alarm systems are available which may sound the horn of the vehicle and switch on its lights. The alarm systems have to be armed by the user, for example by operating a concealed switch or by using a remote transmitter. Another anti-theft device is a key operated shut-off valve in the fuel line.

The problem with all of these known anti-theft d-v ces is that they must be set by the user. The user may simply forget to set the device, or he may just be leaving his vehicle for a moment and decide that not worth the trouble of sett no the anti-theft device. In either of these cases, the device may as well not be there. Vehicle theft involves rlsrr- whether there is an ant-theft device or nct and while the devlces may act as a deterrent to some thieves, other thieves will take the risk that a device has not been set.

A further problem is that in certain of these cases the car can still be driven. Where there is an alarm, for example, if people pay no attention to the alarm, or if there is no-one to hear it then the device will not prevent theft. Where there is a key-operatea shut-off valve in the fuel line the car may still be driven for a few hundred metres. The steering lock on some cars may be broken by leverage with a crow-bar.

According to the invention there is provides a vehicle including a device which is operated automatica iz to render the vehicle undrivable and can only activated by means speciiic to the user.

In this way, the device noes nct have to be because it is operated automatically any cni tr:e user can re-activate the vehicle.

The device may render the vehicle undrivable @n any suitable way, but preferably the device is arranged to lock the transmission of the vehicle. Thus device prevents the vehicle from being towed sway, or pushed out of earshot of the owner so that he 1:1 not hear the engine being started or any alarm going off Where the vehicle has an automatic transmission which includes a "park" conduit on he device is preferably arranged to lock the transmission in the "park" condition. The transmission may be locked in the "park" condition by any suitable means such as mechanical means. In addition or alternatively, where the vehicle includes an internal combustion engine, the device may break the ignition and/or starter motor circuit of the engine.

Preferably, the device includes activating means including at least one sensor in response to a signal from which the activating means activates the device to render the vehicle undrivabie. The activating means may include a sensor to sense whether the vehicle engine is running. Hence, the activating means will only activate the device when the vehicle engine is not running. The activating means may include a sensor to sense whether the transmission ss braked or locked. For example, in an automatic transmission including a "park" condition the sensor may sense whether the transmission is in the "park" condition. Where the vehicle is operated by a key, the activating means may include a sensor to sense whether the key is in the keyhole. Hence, the device may only be activated when the key is not in the keyhole. Preferably, the activating means of the device includes all three of the above described sensors. It is noted that the sensors sense the condition in which a vehicle will be left by the user.

The user will stop the engine, lock the transmission, for example, by pulling on the handbrake or by putting the transmission into "park" and will remove the ignition key. As the user will do all of these things because he needs to do them, he does not have to think about setting the alarm: it is done automatically.

The vehicle may include a keypad and the device may be arranged to be de-activated by input of a specific code to the keypad. Thus, on return to the vehicle the user can input the code on the keypad and the vehicle will become drivable. Alternatively, the device may be arranged to be de-activated by use of a key to be held by the user. Where the device includes activating means, preferably the or each sensor must provide the appropriate signal to the activating means in order for the device to make the vehicle drivable.

Preferably unless the appropriate signals are provided within a pre-determined time period the device is reset and the input code must be re--ntered. Where a sensor checks that the engine is running, prei-erabi it is also checked that the correct input cod was input before the vehicle is rendered drivable.

The vehicle may be of a vehicle t an kind and may be a vehicle will an internal -ombust on -nglne . The vehicle may be a road-going vehicle such as a car.

One embodiment of the invention will now be described by way of example and with reference to the accompanying drawings, in which: Fig. 1 is a flow diagram for activation of the device and Fig. 2 is a flow diagram for de-activation of the device.

In the embodiment, the vehicle is an automatic transmission car fitted with the device. The device comprises three sensors. The first sensor is a switch in the ignition slot which is operated by insertion of the key, the switch sending a signal to an activation unit of the device which comprises a logic circuit.

The second sensor is an element for monitoring current flow to the spark plugs of the engine which sends a signal to the activation unit when the engine is running and the spark plugs are firing. The third sensor is a mechanical switch which is operated when the gear lever of the car is moved into "park". The mechanical switch also sends a signal to the activation unit.

The activation unit controls relays in the iSiticn and starter motor circuits of the vehicle and also controls the movement of a metal fnger. The gear lever of the vehicle has a number of positions for different driving conditions and the "park" position is entered when the lever is pushed furthest forward.

The metal finger is movable to lie behind the gear lever when it is furthest forwards to prevent it from moving out of the "park" position.

In operation, as shown in Fig. 1, when the driver brings the vehicle to a standstill, turning the engine off with the key will send a signal to the activation means from the first sensor. When the gear lever is placed in '2park" the mechanical switch will send a further signal to the activation means and when the ignition key is then removed, a frtcr signal will be sent from that switch. Once the activation unit receives signals from all three sensors to confirm that the engine is not running, the gear lever is in "park" and the ignition key has been removed then the activation unit will move the mechanical finger behind the gear lever to lock it into the "par:':" posltion and will open the relays in the ignition and starter circuits to break those circuits. The car now cannot be pushed backwards or forwards because ne transmission is locked and furthermore the engine cannot be started because the ignitn and start circuits are broken.

In order to de-activate the lock and render the car drivable, a code must be input to a keypad on the dashboard of the vehicle. Fig. 2 shows the sequence of events. If the input code is correct, a signal is sent to the activation unit which sets a flag to indicate that the correct code has been input. The signal also starts a timer which instigates a delay which in this case is 10 seconds. If the switch in the ignition is operated by insertion of the key within the 10 second delay period then the ignition and starter motor circuits will be closed by operation of the relays by the activation unit. If the key is not inserted in the ignition within 10 seconds then the relays will not be operated and it will not be possible to start the engine of the vehicle without inputting the correct code again. This is to cater for the situation where the driver inputs the code and then is distracted to go and do something else away from the car. Because of the fail-safe introduced by the timer delay the car is locked again and not left unprotected. Once the engine has been started the activation unit checks again that the input code was correct by checking that the code flag has been e+.

This caters for the situation where the car is "hst- wired" and the engine started without use of the t and the corresponding ignition and starter motor circuits. In these circumstances the code flag will not have been set and the transmission lock will not be de-activated. If the engine is running and the flag has been set then the lock will be de-activated releasing the gear lever so that it can be moved from the "park" position and the car driven in the normal way.

Any suitable means may be used to lock the transmission in the alternative to the metal finger described. In the case of manual transmission cars, either a "park" position may be introduced, or some other part of the transmission may be locked.

Claims (18)

1. A vehicle including a device which is operated automatically to render the vehicle undrivable and can only be re-activated by means specific to the user.

2. A vehicle as claimed in claim 1, wherein the device is arranged to lock the transmission of the vehicle.

3. A vehicle as claimed in claim 2, wherein where the vehicle has an automatic transmission which includes a "park" condition, the device is arranged to lock the transmission in the "park" condition.

4. A vehicle as claimed in claim 3, wherein the transmission is locked in the "park" condition by mechanical means.

5. A vehicle as claimed in any preceding claim, wherein where the vehicle includes an internal combustion engine, the device breaks the ignition and/or starter motor circuit of the engine.

6. A vehicle as claimed in any preceding claim, wherein the device includes activating means including at least one sensor in response to a signal from which the activating means activates the device to render the vehicle undrivable.

7. A vehicle as claimed in claim 6, wherein the activating means includes a sensor to sense whether the vehicle engine is.running.

8. A vehicle as claimed in claim 6 or claim 7, wherein the activating means includes a sensor to sense whether the transmission is brake or locked.

9. A vehicle as claimed in claim 6, 7 or 8, wherein where the vehicle is operated by a key, the activating means includes a sensor to sense whether the key is in the keyhole.

10. A vehicle as claimed in any of ciaims 6 to 9, wherein the or each sensor must provide the appropriate signal to the activating means in order for the device to make the vehicle rivable.

11. A vehicle as claimed in any preceding claim, wherein the vehicle includes a keypad and the device is arranged to be re-activated by input of a specific code to the keypad.

12. A vehicle as claimed in claim 11 when dependent on claim 10, wherein the device is such that unless the appropriate signals are provided within a pre-determined time period the device is re-set and the input code must be re-entered.

13. A vehicle as claimed in claim 11 or claim 12, wherein where a sensor checks that the engine is running, it is also checked that the correct input code was input before the vehicle is rendered drivable.

14. A vehicle as claimed in any of claims 6 to 10, wherein the device is arranged to be re-activated by use of a key to be held by the user.

15. A vehicle as claimed in any preceding claim, wherein the vehicle is a vehicle with an internal combustion engine.

16. A vehicle as claimed in claim 15, wherein the vehicle is a road going vehicle.

17. A vehicle as claimed in claim 16, wherein the vehicle is a car.

18. A vehicle with a device substantially as described herein with reference to the accompanying drawings.