The present invention relates to an arrangement for prevent- ing a motor vehicle from passing beyond a specific place unauthorized.

A problem which is becoming ever more serious in present day communities resides in the theft of vehicles and their exportation to foreign countries.

The prime object of the present invention is to alleviate this problem by making it difficult for a stolen vehicle to pass through customs unnoticed.

This object is achieved with an arrangement which functions to prevent a motor vehicle from passing beyond a specific location unauthorized and which is characterized in that said specific location has placed therein a transmitter which transmits a specific radio signal of limited range; in that the vehicle includes a receiver which is responsive to said specific radio signal and which upon receipt of said specific signal activates a check means provided in the vehicle, said means checking whether or not the vehicle is authorized to pass the specific location and which is constructed to activate one or more electronic circuits in the vehicle in a manner which will render the vehicle inoperable, in the event that the vehicle is not authorized to pass beyond said specific location. This will then draw the attention of the customs personnel to the fact that the vehicle is not authorized to leave the country, for one reason or another.

According to one preferred embodiment of the invention, the transmitter mounted in the specific location is a transponder which delivers a modulated reflected signal in response to a signal transmitted by a vehicle mounted transmitter when the transponder is located within the range of the vehicle

transmitter.

The check device is preferably constructed to activate a vehicle alarm circuit when the vehicle is unauthorized to pass beyond the specific location.

The invention will now be described in more detail with reference to the accompanying drawings, in which Figure 1 illustrates schematically a customs station equipped with one embodiment of an inventive arrangement; and

Figure 2 is a schematic functional diagram of the arrangement shown in Figure 1.

Figure 1 illustrates a motor vehicle 1 on its way through a customs station. The vehicle 1 is equipped with a device 2 in accordance with the invention. This device includes a transceiver 3 which when the vehicle ignition is switched-on continuously transmits a radio signal of limited range, preferably a ^* range of 10-50 m. Mounted in the custom station is a transponder 4 which is receptive to the signal transmit¬ ted by the unit 3 in the vicinity of the border crossing. The transponder 4 is adapted to reflect a modulated signal in a known manner, in response to the signal from the device 2. When the unit 3 receives the response signal, the unit sends a signal to a check means 5 included in the device 2, said means checking whether or not the vehicle is authorized to leave the country. If this check indicates that the vehicle is not authorized to leave the country, the check means delivers a signal which, via a device 6 activates one or more electronic circuits in the vehicle such as to render unser¬ viceable one or more of the vehicle functions. For instance, the device 6 may be constructed to break the current supply to the vehicle ignition system.

According to one preferred embodiment of the invention, the device 6 consists in a code unit having an electronic lock of the type described in SE-B-469 704 and marketed by

Scarinus AB under designation SC 202. A plurality of conduc¬ tors pass through the code unit 6 from an engine control unit 7, which controls engine functions, and the code unit makes it impossible to bypass the electronic lock. Reference is made to the aforesaid patent specification for closer details of the construction of the code unit. The code unit 6 includes a microprocessor which upon receipt of a signal from the check means commands the code unit to break the current supply to the ignition system for instance. The arrangement 2 is also constructed to send a signal to the code unit continuously while the vehicle is running, so as to make it impossible to avoid the effect of a stop signal from the check means by simply dismantling the arrangement 2.

Thus, it must be possible to switch the check means 5 between a first position or state in which a signal is delivered to the code unit 6 upon receipt of a response signal from the transponder 4, therewith rendering the vehicle unserviceable, and a second position or state in which no signal is sent to the code unit upon receipt of the response signal, therewith enabling driving of the vehicle to be continued. In its simplest form, the check means may include a relay or a switch which in a respective first state or position estab¬ lishes a conductive connection between the receiver 3 and the code unit 6, and which in a respective second state or position breaks this connection, and an externally maneuver- able relay or switch control means. This control means may, for instance, have the form of a rotational pin or tumbler in a key operated cylinder lock, which when turned by the key mechanically adjusts the switch, or an electronic unit which includes a button bank, or some other device by means of which a code can be delivered to the unit, and a device for comparing the input code with a prestored code and for delivering a re-setting signal to the relay when agreement exists.

When a vehicle 1 equipped with the arrangement 2 approaches

a customs station that is equipped with a transponder 4, the transponder will be activated by the vehicle when said vehicle is located at a limited distance from the transponder and therewith delivers a response signal to the arrangement 2. If the vehicle has no authorization to pass the customs border, i.e. if the check means has not been switched to its second state or position, the vehicle engine will be stopped through the medium of the code unit 6, a circumstance which should cause the customs personnel to check the vehicle. In order for the vehicle to be started and driven, it is necessary to roll the vehicle out of the customs station and beyond the range of the transponder 4. In this regard it should be mentioned that the range of the transponder signal should not be greater than the area covered by the customs station so that the vehicle will not be influenced by the signal outside this area. According to one variant of the invention, the code unit 6 may also be constructed to activate an alarm circuit when it receives an unauthorized vehicle indicating signal from the check means 5, which should further draw the attention of the customs personnel to the effect that the vehicle should be checked.

Naturally, the described arrangement can be used in contexts other than the passage of a vehicle across a manned border point. For instance, the invention can be applied in the context of vehicle parking or vehicle accommodation areas which are closed during certain periods of the day, by installing in these areas a transponder which is activated during these closed periods, thereby preventing the vehicle from being driven away from the parking area unauthorized.

It will be understood that the described and illustrated embodiment of the invention can be modified in several ways within the scope of the invention, particularly with regard to the construction of the check means. For instance, one or more conductors in electronic circuits may be passed through the check means, and the check means may be adapted to break

the current supply to these circuits directly when an unauthorized vehicle attempts to pass a specific location. The transmitter installed at this specific location may be constructed to deliver a signal continuously to a vehicle mounted receiver, which in this case requires no transmitter. The invention is therefore solely limited by the contents of the following claims.