A deactivation device comprising a telephone receiver provided to receive an emergency signal that is emitted via a telephone connection, and upon reception of the emergency signal to generate a control pulse, which receiver is connected with an interrupt switch which is provided to deactivate under control of said control pulse driving means, in particular the driving means of a vehicle.

Such a deactivation device is described in the PCT patent application WO 94/29148. The device described therein is destined to deactivate the driving means of the vehicle. Thus for example, by means of the interrupt switch the fuel supply of the vehicle is shut off when the device is switched on. The device reacts upon a power decrease in the power circuit of the vehicle, which power decrease takes place because the receiver has received an emergency signal sent through the telephone. Due to this reception, the device is activated, thus supplying power from the power circuit. This power decrease has a well determined sequence that is decoded.

The PCT patent application WO 93/17895 also describes such a deactivation device where the receiver receives a code word that is compared with a codeword that is particular to the vehicle. If they correspond, the driving means are deactivated.

A disadvantage of the detection and the comparison of codewords is that it is not sufficiently reliable for such an application. As a matter of fact, even a small disturbance upon reception leads to the determination that it is not the right codeword that has been received, and consequently no deactivation takes place. Furthermore, to

large tolerances can not be allowed either because this would lead to a false alarm.

This invention differs from the described deactivation devices by the fact that, on one hand it does not function by codeword comparison, and on the other hand, nor with power decrease. The latter also causes problems because it is necessary to accurately detect the decrease sequence in order to realise a reliable operational device. The deactivation device according to the invention is characterized in that the interrupt switch comprises a control circuit provided with a control input, which control circuit is electrically closable and interruptible under control of the control pulse injected at the control input. Decoding of a codeword or of a power decrease sequence is no longer necessary because it is sufficient to detect the reception of an emergency signal to generate the control pulse. This control pulse is then injected in the control circuit closing or interrupting the latter, according to whether the authorized user activates or deactivates the device. Consequently, when a disturbance impulse is received, then a correct control pulse signal that is able to close or open the control circuit will not be generated. The device can thus function reliably. A first preferred embodiment of a deactivation device according to the invention is characterized in that the interrupt switch contains a deactivation member provided for the deactivation of a supply source of the driving means, which deactivation member is connected with the control circuit via an pulse delay line. The pulse delay line is intended to avoid an abrupt deactivation of the driving means after reception of the emergency signal.

A second preferred embodiment of a deactivation device according to the invention is characterized in that said codeword receiver is provided for the reception of a sequence of binary digital codewords normalized according to POCSAG (Post Office Code Standardization Advisory

Group) . An existing infrastructure is thus used and the codeword is sent and received in a reliable manner.

A third preferred embodiment of a deactivation device according to the invention is characterized in that said interrupt switch comprises a bistable hold relay. Such a relay has the advantage that, once it is switched into a position, it remains stable in that position. The deactivation of the driving means also remains stable.

A fourth preferred embodiment of a deactivation device according to the invention is characterized in that the control circuit comprises a safety element provided to repress reset pulses that are not generated by the receiver. Consequently, the driving means can only be activated again by the person who knows the call number. Attempts to render the device unserviceable or to bypass it are thus doomed to fail.

It is favourable that the control circuit comprises a safety element provided to repress reset pulses that are not generated by the receiver. By coupling and uncoupling the battery poles it is sometimes possible to reset a system and doing so, undo the functioning of the deactivation device. The safety element protects the device against such reset pulses.

The invention will now be further described by means of the examples shown in the drawings. In the drawings:

Figure 1 shows a block diagram of a deactivation device according to the invention; and

Figure 2 (a + b) is a detailed embodiment of a deactivation device according to the invention. In the drawing, a same reference number is attributed to a same or analogue element.

The deactivation device according to the invention is schematically shown in figure 1 and comprises a receiver and a control circuit 1. The control circuit is connected with an alarm signal generator 4 on one hand and on the other hand with an input of an pulse delay line 2. An output of the pulse delay line is connected with an

interrupt switch 3 provided to deactivate the driving means 5.

Preferably, the deactivation device is destined to be installed in a vehicle. The interrupt switch is then for example connected to the ignition, the fuel pump or the motor management system. The deactiyation device can also be used for other applications such as for example utility installations in particular or industrial buildings.

The receiver 1 is provided with a reception antenna 6 destined to receive an emergency signal generated and emitted via a telephone connection. The receiver is preferably formed of a semaphone, for example a semaphone of the BRAVO type commercialised by Motorola (registered trademark) . Such a receiver is provided to receive a sequence of binary digital codewords normalised according to POCSAG (Post Office Code Standardization Advisory Group) . The advantage of such a receiver is that it is available on the market and consequently uses the existing infrastructure. Moreover, this receiver functions in a reliable manner and uses little energy.

The interrupt switch 3 is provided with a deactivation member that is preferably formed of bi-stable hold relay. Such a relay comprises two positions and switches from one position to the other upon reception of a control pulse, and remains in that position until another switching pulse is generated at the control input. The fact that the relay remains in said position is favourable because in doing so, once deactivated, the driving means also remain deactivated. The alarm signal generator 4 is for example formed by a switch or a block pulse generator. The alarm signal generator is destined, when a control pulse is supplied by the detector, to generate an alarm signal and in such a manner to indicate that the driving means will be deactivated. When the deactivation device is installed in a vehicle, the alarm signal generator is connected with

the horn and/or the indicators in order to produce a sound and/or a light signal.

The functioning of the deactivation device according to the invention will now be more thoroughly explained by means of an example where it will be understood that the device is installed in a vehicle.

Suppose that the vehicle is hijacked or stolen. The driver or owner, who is the victim of the hijacking or theft, will then run to the nearest telephone booth as quickly as possible and call up the receiver, component of the device. Once the telephone line is established, the receiver receives the thus emitted emergency signal and becomes active and generates a control pulse that is presented to the alarm signal generator 4 and the control circuit l.

The pulse delay line 2 delays the transmission of the control pulse to the deactivation member for a predetermined time span of 30 seconds for example, in such a manner the thief or hijacker has enough time to leave the circulation and to park the vehicle on the side of the road in order not to disturb the remaining circulation once the vehicle is stopped. Once the said time span is over, the control pulse is injected in the control circuit and thereafter the driving means are deactivated immobilizing the vehicle. Because the vehicle is immobilized, the thief or hijacker is forced to leave the vehicle behind. Towing the vehicle without the intervention of the owner or authorized driver does not make much sense since the vehicle can only be reactivated by a new call of the receiver.

The owner of driver can then, with or without the help of the police, start searching for his vehicle. If the vehicle is provided with a beep system it can naturally be used. Once the vehicle is found, it is sufficient to call the receiver again to switch back the interrupt switch and in such a manner to reactivate the driving means.

Figure 2 shows a detailed embodiment of a deactivation device according to the invention. The receiver or semaphone 10 emits, when it is called, an optical _. control pulse signal that is capted by a reception diode 11, that is part of the control circuit 1. The diode 11 is connected with a supply line 17 via a resistance 16. The resistance must have a high accuracy in order to repress the generation of false signals.

Instead of generating an optical signal as control pulse and injecting it in the diode, it is also possible to work with an induction circuit where the control signal is injected in an induction coil. Furthermore, it is also possible to inject the electrical control pulse directly into the control circuit. The optical control signal generated by the receiver renders the diode 11 conductive, whereby the control circuit is closed and current circulates to the basis of the transistor 14 and to the capacitors 12 and 13 that are switched in a parallel manner with the basis and the emitter of the transistor 14. The capacitors 13 and 14 ensure that shorter flash switch pulses originating from the receiver 10 are repressed so that they do not lead to a reset via the main supply, for example via coupling and uncoupling of the accumulator and that the transistor 13 only switches upon a predetermined signal emitted by the receiver 10, for example the signal stored in the address 1 when using a Motorola BRAVO receiver.

The switching of the transistor 14 causes the reverse of the polarity of a relay 15. This relay is preferably a double coil separated relay whereby as one contact is closed the other one is opened. When reversing the polarity a control signal is generated that is presented at the output 18 of the relay. It is supposed that the relay is connected here in the same manner as shown in figure 2, namely in the neutral position. The control signal now reaches the alarm signal generator 4 and the

delay line 2 via the line 19. The diode 20 in line 19 serves to protect the relay 15.

The alarm signal generator 4 comprises a thyristor 21 of which an input is connected with line 19 and an output is connected with a impulse generator 22, for example a C- MOS HEF 40106. A control input of the impulse generator 22 is connected with a RC connection 24 destined to establish the impulse period of the impulses generated by the generator 22. An output of the impulse generator 22 is connected with the basis of a transistor 23 via a diode and a resistance. The collector of the transistor 23 is connectable with a light and/or sound signal source such as for example the indicators and/or the horn of the vehicle wherein the device is installed. When the control signal is presented at the input of the alarm signal generator, the latter will emit a series of impulses at its output in order to activate the light and/or sound signal source therewith and in such a manner to generate an alarm signal. The delay line 2 comprises a diode 25 connected with line 19 destined to protect the relay 15. The cathode of the diode 25 is connected with the collector of a transistor 26 via a resistance 27. A resistance 28 is connected between the basis and the collector of the transistor 26. The control signal reaches the delay line 2, via line 19, where it flows towards a capacitor 29 via the diode 25 and the resistances 27 and 28. This capacitor is thereby charged and will, once it is charged, discharge itself via the resistance 30. The discharging of the capacitor 29 has for consequence that the transistor 28 becomes conductive. Thereby, the transistor 31 also becomes conductive, which has as consequence that the voltage level on line 32, containing the resistance 33 and the diode 34, becomes negative. Because line 32 is connected with an input 36 of an impulse generator 35, a negative voltage level is presented to this input 36. The pulse generator 35 is for example formed by an integrated

8 circuit HEF 4093, which is connected as a Schmitt-trigger in this configuration. The negative voltage level at the input 36 assures that a pulse with high voltage level is supplied at the output 37 of the pulse generator 35. Output 37 is connected with a further output 39 of the pulse generator 35 via a capacitor 38. At the output 40 of the pulse generator, after charging the capacitor 38, a control pulse is supplied that is presented to the basis of the transistor 43 via the diode 41 and the resistance 42. The transistor 43 amplifies this last control pulse and the invertor 44 inverses it in order to supply it to the transistor 45 with a greater switching capacity. The collector of transistor 45 is directly connected respectively via the diode 47 with a first control input respectively a second control input of the interrupt relay 46. The latter is preferably formed by a bi-stable hold relay. This relay has the advantage that it is protected against sturdy current surges. Presenting the control impulse at the first control input has as consequence that the interrupt relay switches to the position 48b and thus interrupts the current circuit that is connected over that relay. When the driving means of the vehicle are switched over that relay they thus become deactivated. In order to switch the interrupt relay over to position 48a again, an inverted impulse must be supplied to the second control input. Upon attracting the interrupt relay 46, the control pulse is also sent via the diode 49 towards the relay 15 in order to reset the latter. The pulse generator 22 remains nevertheless active via the thyristor 21.

The connection 50 is a supply for the codeword receiver known as such and will thus not be further described.