GB2108189A - Anti theft device for motor vehicle - Google Patents

Abstract

The invention relates to an anti- theft device which comprises a coded key operated mechanism 1 and an inaccessibly located lock mechanism 2, connected to each other by wires 3 to 8. A microprocessor 13 in the key operated mechanism 1 controls the reading of the key code and transmits a signal to a slave microprocessor 19 in the lock mechanism to move the bolt into positions corresponding to the "park", "ignition" and "accessories" positions in dependence upon the received instructions and, if required, other parameters such as movement of the vehicle, the position the gear lever or buckling of the seat belts. The key 11 may have coded perforations (35, Fig. 3, not shown), which are read by an array of electroluminescent diodes 9, 10. <IMAGE>

Description

SPECIFICATION Anti-theft device for motor vehicle The invention relates to anti-theft devices designed to lock an element shich is essential to the operation of the vehicle, such as the steering column, and simultaneously to ensure the switching of the electrical circuits of the vehicle. These anti-theft devices therefore provide a double safety against theft since, in the locked position the vehicle is immobilised mechanically and its electrical circuits are open which prevents in particular starting and the supply to the motor.

Anti-theft devices of this type used up to now comprise, in the same housing, a safety lock controlled by a key, the rotation of the lock cylinder controlling the movements of a locking bolt and simultaneously the actuation of an electrical switch.

Although these known anti-theft devices are in general satisfactory, they have various drawbacks. The first drawback is that they are very vulnerable, the technical means available to thieves enabling them to unlock the look relatively easily using fairly simple and readily aviable instruments. Moreover, the construction of the anti-theft device in a singie block containing both the lock, the locking bolt and its control means, as well as the electrical switch makes them particularly sensitive to burglary attempts. The lock must necessarily be accessible and may therefore be subject to burglary attempts using various methods such as forced rotation of the cyliner, forced depression of the cylinder, removal of the cylinder etc.

The present invention aims to provide a new anti-theft device for an automibile vehicle which does not have the drawbacks of known anti-theft devices by means of the use of an electronic lock controlling a lock unit which is distanced and inaccessible, these two elements being connected by a burglar-proof connection.

For this purpose, the invention relates to an anti-theft device for an automobile vehicle comprising a locking bolt arranged to engage with an element locking the vehicle, such as the steering column, characterised in that it comprises: a) an electronic lock comprising a coded key, a device for controlling the operation of the anti-theft device during the introduction and removal of the key and a device for reading the key code and for generating a corresponding signal;; b) a bolt housed in an inaccessible housing and comprising a locking bolt controlled by an actuator, a device for receiving signals transmitted by the lock and for comparison with coded signals contained in a memory, an electronic device for controlling the actuator and an electrical supply switch for the vehicle, the electronic control device receiving the signals transmitted by the receiver and comparison device and signals representing the position of the locking bolt and the rest or operational condition of the motor of the vehicle; c) connections between the lock and the bolt ensuring the electrical supply to the lock, the transmission of the coded signals between the lock and the bolt, and the transmission of the operating control of the anti-theft device from the lock to the bolt.

The use of an electronic lock enables a considerable increase of the number of combinations possible and thus considerably strengthens the security of the anti-theft device. The transmission of the bolt control in the form of coded signals prevents the unauthorised actuation of the bolt even by direct action on the bolt aperture. The arrangement of the bolt in an inaccessible housing prevents any direct action on the locking bolt control actuator.

The key preferably comprises coded perforations and the reading device comprises an electroluminescent diode matrix, a receiver diode matrix disposed opposite the electroluminescent diodes, and a circuit for forming the signal transmitted from the receiver diodes.

In a preferred embodiment the lock comprises an electronic device arranged to generate, from signals transmitted by the lock, the signals required for reading of a key, and a circuit designed to supply the currents required for the excitation of the electroluminescent diodes.

The key advantageously comprises a slot for positioning with respect to the diode matrices.

The lock preferably comprises a device for generating a starter control signal constituted by a contactor disposed at the end of the lock so as to be actuated by the key when it is completely inserted into the lock, resilient means returning the key opposite the diode matrices as soon as it has been released.

The invention also relates to several preferred embodiments of the bolt. In accordance with one of these embodiments, the bolt comprises a pilot circuit supplied directly by the accumulator battery of the vehicle and ar ranged to circulate the electrical supply of the anti-theft device on reception of a control signal transmitted by the lock during a move ment of the key. The electronic control device contained in the bolt advantageously controls the discontinuation of the electrical supply from the anti-theft device after the operations of the latter have been carried out.

In a particularly advantageous embodiment of the invention, the locking bolt is controlled by a d.c. electrical motor by means of an endless screw. The locking bolt may occupy a locked position and an unlocked position, and a garage position. The electrical switch is advantageously linear and the movable con tacts are supported by the locking bolt which is slideable.

The invention is now described in further detail with reference to the accompanying drawings, in which: Figure 1 is a circuit diagram of an anti-theft device in accordance with an embodiment of the invention; Figure 2 is an exploded perspective diagram of the optical-electronic key reading device of the anti-theft device of Fig. 1; Figure 3 is a plan diagram of a key used with the device of Fig. 2; Figure 4 is a perspective diagrm of the electromechanical portion of the bolt of the anti-theft device of Fig. 1.

The anti-theft device comprises a lock 1 and a bolt 2 connected by connnection wires 3, 4, 5, 6, 7 and 8.

The lock 1 comprises an electroluminescent diode matrix 9 and a receiver diode matrix 10, preferably operating in the infrared range and between which a key 11 may pass. The receiver diode matrix is connected to the input of an amplifier circuit 1 2 whose output is connected to the input of a micro-processor 1 3. The micro-processor 1 3 is connected to the input of an amplifier 14 of the supply of the diode matrix 9.

During its displacement, the key 11 actuates a supply contactor 1 5 connected to a d.c.

supply 16, for example 5V, by the connection wires 10 and 11. The key 11 also actuates, when completely inserted, a starter contactor 1 7 connected to the wire 11 and to a starter relay 1 8 by the wire 14.

The microprocessor 1 3 of the lock 1 is connected to a microprocessor 1 9 of the bolt 2 by a bidirectional connection wire 9 and an output of the microprocessor 1 9 controls the supply 16, which receives, in addition to the control wire 10 and the 1 2V supply wire 11, the 5V supply wire 1 2 and the earth wire 1 3.

The microprocessor 1 9 is supplied by a programmable code memory 20, via lines 21, 22, 23 from switches 24, 25, 26 respectively which are actuated by the locking bolt 27 during its translation. The microprocessor also has an input connected to a line 28 which is connected to an engine movement indicator and a further input connected to a line 29 connected to a vehicle displacement indicator.

An output of the microprocessor 1 9 is connected to the starter relay 1 8 and another output to an amplifier 30 controlling the electrical motor 31 for actuating the bolt 27 by an endless screw 32.

The key 11 slides in the key slot 34 of a housing 33 supporting the diode matrices 9 and 10 and the contactors 15 and 17. The key comprises coded perforations 35 which are read by the diode matrices, and a notch 36 for positioning the key with respect to the diode matrices. Resilient means (not shown) return the key 11 opposite the the diode matrices 9 and 10, after depression of the end contactor 1 7 and release of the key, by engagement of the notch 36 with a positioning member (not shown).

The locking bolt 27 supports a movable element 37 provided with two contacts 38, which are connected, in accordance with the position of the bolt 27, with locking position contacts 39, garage position and accessory supply contacts 40 and contacts for the operating position and for the general electrical supply of the vehicle 41, which constitute the switches 24, 25, 26 respectively.

The operation of the above-mentioned device is as follows: The introduction of the key 11 into the key slot 34 actuates the switch 15, which, by means of the pilot circuit, switches on the supply 1 6 of the electronic assembly of the anti-theft device. The microprocessor 13, supplied in this way, supplies the amplifier 14 which supplies the diodes 9. The diode matrix 10 receives the radiation from the diodes of the matrix 9 which has passed through the perforations 35 of the key 11 and the signal generated in this way is supplied to the microprocessor 1 3 after amplification in the amplifier 12.

This signal is applied by the line 9 to the microprocessor 1 9 which also receives the content of the memory 20 and compares the two signals. If they are different, after several attempts it transmists an alarm signal via a line 42.

If they are identical it supplies a command to the motor 31 by means of the amplifier 30 which causes displacement of the bolt 27 to the "contact" position.

At the end of insertion, the key 11 actuates the switch 1 7 which supplies a signal to the starter relay 1 8. The key 11 then returns automatically into the reading position opposite the diode matrices 9 and 10. The microprocessor 19, if the line 28 supplies it with a signal indicating that the engine of the vehicle has stopped, supplies a signal to the relay 18 which actuates the starter.

At the end of this process, the bolt 27 is in the operating position, as its contact 38 is contacted with the fixed contact 41 such that the electrical supply of the vehicle is ensured.

The engine of the vehicle is started under the action of the starter and the vehicle is operative. The supply 1 6 is cut off by the microprocessor 1 9 such that the anti-theft device only has the pilot current passing through it.

If the operator withdraws the key 11, the switch 1 5 is again actuated and the supply 16 is re-actuated. The microprocessor 1 9 analyses the data transmitted to it by the line 29.

If the vehicle has stopped, a command is supplied to the engine 31 which brings the bolt into the locking position. The supply 1 6 is then cut off. If the vehicle is not stationary, no command is supplied to the engine 31 and the supply 1 6 is cut off. In order to stop the key 11 should be re-inserted, which resets the supply 1 6 and brings the electronic system to the normal operating position. By repeated extraction, with the vehicle stopped, the bolt moves into the locking position. The displacement of the movable contact 38 cuts off the electrical supply of the vehicle, and its engine stops. The electronic system then returns to the pilot condition.

If the key 11 is not completely inserted during the first insertion, the switch 1 7 is not actuated, a time lapse occurs and the microprocessor 1 9 then supplies a message to the engine 31 which causes the passage of the bolt 27 to the "garage" position. Two actions on the contactor 1 7 are then required to bring the bolt 27 into the "operating" position and to produce starting of the engine of the vehicle. On the other hand, withdrawal of the key 11 automatically produces the passage of the bolt 27 into the locking position.

For a voluntary passage into the "garage" position" the operator inserts the key without actuating the switch 1 7 and depresses, in a given time lapse, a button (not shown) which supplies a signal to the microprocessor 1 9 which supplies a command to move into the "garage" position to the engine 31. If the button is not actuated within the given time lapse, the microprocessor 1 9 supplies a command to pass into the locking position on withdrawal of the key.

Numerous options may be provided with the electronic anti-theft device of the invention. For example, a change of code may be provided by introducing a new code into the memory 20, wherein this new code may only be introduced in the presence of the key for the previous code.

The key 11 may be made of any suitable material and the perforations 35 may be drilled by any known method. They may be made invisible to the naked eye, for example by covering them with an opaque material which may be traversed by the radiation from the diodes 9. The reproduction of the keys is thus made difficult.

The microprocessor 1 9 has the role of "master" with respect to the microprocessor 1 3 which is the "slave". The microprocessor 1 3 is used essentially to read the key whilst all the commands are given by the microprocessor 1 9 which is inaccessible.

The use of a pilot current even while the vehicle is operating enables the current consumption of the anti-theft device to be negligible and provides a very good immunity to electronic noises as soon as the key is no longer being moved. In addition the re-supply of voltage to the microprocessors on each movement of the key zero-sets them, which prevents any starting in a random position.

Any defect or breakdown of any part of the anti-theft device may not have any serious consequences. In effect, the command to pass to the locking position may only be given if the assembly of the anti-theft device is functioning correctly and if the locking conditions are provided. These conditions, which include in the embodiment described, the stoppage of the vehicle and the switching off of its motor, may also include further conditions such as the switching off of the headlights. Moreover, starting may be subject to additional conditions, for example buckling of the safety belts, gear lever in the neutral position, etc.

Claims (11)

1. An anti-theft device for an automobile vehicle having a locking bolt arranged to cooperate with an element locking the vehicle, such as the steering column, the anti-theft device including; a) an electronic lock comprising a coded key a control device for the operation of the anti-theft device during the introduction and extraction of the key and a reading device for the code of the key and for generating a corresponding signal;; b) a bolt housed in an inaccessible housing and comprising a locking bolt controlled by an actuator a device for receiving the signals transmitted by the lock and for comparison with coded signals contained in a memory an electronic control device for the actuator and a switch for the electrical supply of the vehicle, the said electronic control device receiving the signals transmitted by the reception and comparison device as well as the signals representing the position of the locking bolt and the rest or operating position of the engine of the vehicle; and c) connections between the lock and the bolt ensuring the electrical supply of the lock the transmission of the coded signals between the lock and the bolt and the transmission of the anti-theft device operation command from the bolt to the lock

2.A device as claimed in claim 1, in which the key comprises coded perforations and the reading device comprises a matrix of electroluminescent diodes a matrix of receiver diodes disposed opposite the electroluminescent diodes and a circut for shaping the signal transmitted by the receiver diodes.

3. A device as claimed in claim 2, in which the electroluminescent diodes transmit in the infrared range of the spectrum.

4. A device as claimed in one of claims 1 to 3, in which the lock comprises an electronic device arranged to generate, from signals transmitted from the bolt the signals required for reading of a key as well as a circuit designed to supply the currents required for the excitation of the electroluminescent diodes.

5. A device as claimed on one of claims 1 to 4, in which the key comprises a positioning notch with respect to the diode matrices.

6. A device as claimed in one of claims 1 to 5, in which the lock comprises a device for generating a starter control signal constituted by a contactor disposed at the end of the lock in order to be actuated by the key when it is completely inserted in the lock, resilient means returning the key opposite the diode matrices as soon as it is released.

7. Adevice as claimed in one of claims 1 to 6, in which the bolt comprises a pilot circuit supplied directly by the accumulator battery of the vehicle and arranged to provide the electrical supply of the anti-theft device when it receives a control signal transmitted by the lock during the movement of the key.

8. A device as claimed in one of claims 1 to 7, in which the electronic control device contained in the bolt controls the cut off of the electrical supply from the anti-theft device after the operations of the latter have been carried out.

9. A device as claimed in one of claims 1 to 8, in which the locking bolt is controlled by a d.c. electrical motor by means of an endless screw.

10. A device as claimed in one of claims 1 to 9, in which the locking bolt may occupy a locking position and an unlocked position, and a garage position.

11. A device as claimed in one of claims 1 to 10, in which the electrical supply switch is linear and its movable contacts are supported by the locking bolt which is slideable.

1 2. An anti-theft device constructed substantially as herein described with reference to and as illustrated in the accompanying drawings.