GB2219827A - Security device - Google Patents

Abstract

A security device applicable to an article such as a motor vehicle, a building or an electrical appliance comprises a key means which generates a signal, a receiving means which is physically separated from the key means and which is associated with a switch operation of which prevents or permits of access to or operation of the article, and a link by which a signal generated by the key means is transmitted to the receiving means. The receiving means, upon receipt of the correct signal, generates an output such that the switch is actuated to permit of access to or use of the article. The receiving means is associated with the switch such that access to the switch is not possible except by means of use of the correct key means and any attempt to disassociate the switch and the receiving means results in damage to the article such that it becomes inoperable. <IMAGE>

Description

Title: Security Device Description of Invention The present invention relates to a security device and is primarily but not exclusively concerned with a device suitable for use with a vehicle to prevent unauthorised use or theft of the vehicle.

Conventionally access to a vehicle's electrical system is gained by insert ion of a key in a key switch. The user is then enabled to start the vehicle via an ignition circuit.

Prevention of theft of vehicles relies largely on production of a large number of different key shapes each fashioned so as to operate, in theory, only the ignition of one vehicle so that each vehicle is started only by its own key. This system however is readily subverted, as evidenced by the rising number of car thefts, primarily because the key switch switches power to systems which are remote from the switch. Such a system can be subverted in two main ways.

Firstly access to the switch wiring can be obtained and the relevant wires can be short circuited to effect ignition in the absence of a key.

Alternatively vehicle ignition systems can be "hot-wired", that is, short circuit leads can be used to transfer power through to the relevant ignition components directly from the battery.

Devices for combating vehicle thefts have focused mainly on alarms which alert the public to the attentions of an intruder to a vehicle or on installation of steering lacks.

The security device of the present invention is also applicable to articles, constructions and apparatus including buildings which require an input, which input may be a form of energy such as electricity, gas, hydraulic flow etc. to cause operation of or permit of access to the article, apparatus or construction.

For the purpose of convenience only, articles, pieces of apparatus constructions and vehicles will hereinafter be referred to collectively as "articles to be secured".

It is an object of the present invention to provide a new or improved security device.

According to a first aspect of the present invention I provide a security device comprising a switch which is formed integrally with or in permanent securement to an article to be secured or a part thereof, said switch being operative to connect or disconnect said article to be secured from an input, which input permits of operation of or access to the article, wherein key means are provided to cause operation of the switch.

Said switch, in the case of an article to be secured which requires an electrical input, may comprise an electrical switch, where the input comprises an electronic signal it may comprise an electronic switch, and where for example the input comprises a fluid, said switch may comprise a valve.

Said switch may be positioned on said article to be secured and formed integrally therewith or secured thereto in a manner such that irreparable damage will be caused to said article and hence render it inoperable if any attempt is made at access to the switch The provision of said switch formed integrally with or secured to the article prevents by-pcss of the switch to provide an input to the article to be secured, any such by-pcss being prevented by the positioning of the switch on the article or in a casing associated therewith.

It is envisaged that in the case of the vehicle, said switch may be built into at least one of an engine computer circuit or other engine management circuit or electronic ignition, the requirement of an input to said computer or engine management circuit or ignition being essential to enable the engine to be operated.

In the absence of a key it will not be possible to provide an input to said circuit and hence the engine and any vehicle or other apparatus of which the engine forms a part will be rendered inoperative.

Any unauthorised use of said article will require complete removal of the computer or engine management circuit and replacement by a similar circuit to effect operation of said engine.

In a similar manner a piece of electronic apparatus may be protected by incorporation of such a switch which may not necessarily prevent theft of the article but will render the article useless with an inability to provide an input thereto and hence make it's theft unattractive.

Whereas it is preferable that such a switch may be built or formed integrally with an article it is envisaged that it may be provided in a manner so that it may be permanently secured to the article and completely mask or cover any access to an input terminal or connection associated with the article hence necessitating the replacement of the entire article if unauthorised use is to be achieved.

It is envisaged for example that where the article to be secured comprises a vehicle, said switch may be formed integrally with a housing which is adapted to encase at least part of the ignition circuit of the vehicle for example a coil, said switch being operative to permit of or prevent power being supplied to the coil. Preferably in this case said switch will be capable of being operated from within the vehicle to enable proper authorised use of the vehicle.

It is a second object of the present invention to provide new or improved key means for security devices.

According to a second aspect of the invention I provide a new or improved security device including key means and receiving means, the key means comprising a key part in the form of a means for electronically generating a coded first signal and the receiving means operative to generate an output to operate a switch, said receiving means being adapted to receive the first signal which is generated by said key means.

The security device may provide socket means in which the key means may be removably inserted, the key means, when inserted into said socket generating said first signal.

The security device may comprise electronic means for decoding and recognition of the first signal, the electronic means providing, on receipt of the first signal, the output which operates the switch, operation of said switch permitting of use of or access to an article which is to be secured by means of the security device.

The decoding and recognition means may be remote from the key means and the key socket.

A link may be provided between the key socket and the decoding and recognition means for transmission of the first signal therebetween.

The first signal generating means may be a light emitting diode, the first signal may be an optical signal and the link may be an optical fibre link, or, alternatively, the first signal may be an ultrasonic signal or any other suitable signal.

Where the signal is an optical signal the output from the light emitting diode may fall within the infra-red band of the spectrum.

The coded first signal may represent a predetermined digital pattern.

The key means may be powered by energising means and circuitry within the article to be secured, contact points being provided within the key socket, the key part being coupled to said contact points when the key means is inserted in the socket.

The key socket may be permanently powered, or alternatively the power may be switched on at the key socket upon insertion of a conventional key into a separate conventional key socket in the article to be secured and/or upon turning of said conventional key in said conventional socket or power may be switched on at the key socket by any other suitable means.

The key part may comprise an encoding integrated circuit the power supply to which may be protected by means of reed relays which isolate the device from external power pick up contacts which are designed for the key.

The reed relays may be activated by a magnet when in close proximity to or during insertion of the key means into the socket, the magnet being provided at the socket.

The reed relays may be self contained, surface mounted reed relays having operating coils associated therewith.

The key means may comprise a body providing, in combination, both electronic signal encoding and emitting means and a conventional type key shank.

The key socket may be so constructed as to be usable only with a key means having both electronic signal encoding and emitting means and a conventional type key shank, for example the socket may provide a barrel which includes both electrical contact points to which contacts on the key part are coupled when a key means is inserted in the barrel and an aperture in which may be received the shank of a key of conventional shape, insertion of a key shank of the correct shape permitting, by known pin and tumbler mechanisms, rotation of the barrel in a known manner.

The barrel may further include, on a curved surface thereof, a longitudinally extending recess which, when the barrel is actuated to an operative position by use of a key means having a shank which is compatible with the arrangement of that particular key socket, overlies the end of the optical fibre link which is within the socket such that the optical signal generated from a LED on the key means can be transmitted via the optical link to decoding and recognition means elsewhere in the article to be secured.

The optical fibre may be accessible to an LED output from the key only if and when the key also has the appropriate unique shank shape so as to operate the pin and tumbler mechanism of the barrel and socket.

The decoding and recognition means may be associated, within a sealed housing and/or within a part of the article to be secured which part has very poor accessibility, with means essential to use of the article to be secured, a signal output from the decoding and recognition means being necessary to operate the switch and thereby activate the essential means and thus to permit of use of or access to the article to be secured.

The article to be secured may be a motor vehicle.

The key may be powered by at least one cell which is separate from the vehicle's conventional power supply.

The essential means may be any one or more of a door unlocking means, a steering wheel unlocking means which is activated by a solenoid or electronic means, or an electronic braking system.

The essential means may be a starter component of the vehicle such as any one or more of an ignition coil, an electronic ignition unit, an engine management unit, a starter motor, a fuel feed or a glowplug starter system.

The article to be secured may be a building in which case the essential means may be means to open access restricting means of the building such as a door lock.

The essential means may alternatively be an alarm system for a building.

The optical fibre link may abut against a receiver diode part of the decoding and recognition means which receiver diode is spectrally matched to the peak optical wavelength of the signal to be transmitted.

The decoding and recognition means may comprise an amplifier, decoder and an electronic latching means such as a thyristor, a triac or a relay, which latching means, upon receipt of the correct signal pattern at the decoding and recognition means transmits an output signal to the switch.

Where the essential means is a vehicle door unlocking mechanism the output signal may activate solenoids which are built into the vehicle door or door pillars.

The decoding and recognition means may include an integrated circuit.

The number of usable signal patterns may be determined by the nature of remote control integrated encoding and decoding circuits used on the key and in the decoding and recognition circuitry respectively and by varying the transmittion speed (bit rate) by a combination of resistors and capacitors associated with those integrated circuits or by means of a crystal depending on the particular kind of integrated circuit used.

Preferably the encoding and decoding integrated means are provided with power by a 5 volt, low drop out type regulator such that each will operate within a constant parameter range under all vehicle load conditions.

According to a third aspect of the invention I provide a means for disabling a vehicle comprising a switch which is sealed within a housing which housing also encases at least a part of the ignition circuitry of the vehicle, the switch being activated to permit of ignition of the vehicle by a unique, coded optical signal said optical signal being transmitted by an optical coupling system which extends between the switch and a remote electronic key and socket arrangement which key, when inserted in the said socket generates the optical signal.

The security device according to the invention has the advantage of providing a system which is superficially familiar in operation e.g. the insertion of a key within a socket.

The following description includes, by way of example, the application of the security system specifically to the disabling of a vehicle ignition system.

In an existing vehicle in which the security device may be incorporated a conventional ignition switch may be retained, that is an ignition switch which switches the vehicle off, switches on ancillary circuits such as a radio, switches power to the ignition circuits, and switches power to the starter solenoid.

In use, the security device according to the invention renders one of the ignition circuits vital to starting of the vehicle a "protected" circuit. In the case of an existing vehicle into which the security device is incorporated, the protected circuit will only respond to insertion and turning of a conventional key in the conventional ignition socket provided that a suitable electronic key has been inserted in position within its own socket.

In vehicles which are yet to be constructed, the electronic key and socket device obviates the need for a conventional ignition key and socket arrangement. Such a conventional arrangement could be retained if desired to switch power to the electronic key socket but the conventional key need not be removable.

The security device according to the invention is preferably utilised within a vehicle which uses electronic ignition or has an engine management unit installed although it may be applied to a vehicle not having these features, in which case it involves use of a purpose built ignition coil or starter motor in the case of diesel engines, or else modification of a conventional ignition coil or starter motor using accessory parts.

Specific embodiments of the present invention will now be described in more detail by way of example only, including an embodiment describing use of the security device as a means for disabling a vehicle ignition system. The embodiments will be described with reference to the accompanying drawings wherein: FIGURE i is a schematic diagram showing the relationship of the electronic key and socket to the ignition system of a vehicle.

FIGURE 2 shows an electronic key and socket according to the invention.

FIGURE 3 is a circuit diagram showing the encoding circuitry of the electronic key and socket.

FIGURE 4 is a circuit diagram showing the decoding and recognition circuitry.

FIGURE 5 shows a modified ignition coil for a vehicle having attached thereto a housing which encases the decoding and recognition circuitry.

FIGURE 6 is a diagramatic representation of a part of a vehicle incorporating an electronic door locking system according to the invention.

FIGURES 7 to 10 show examples of electronic keys according to the invention in combination with and comprising part of conventional keys which are already known for use in, for example, automobiles.

FIGURE 10 shows the protection circuitry for the key electronics of the keys shown in Figures 2 and 7 to 9.

FIGURE II shows a key socket which is suitable for use with a combination electronic and conventional key such as is shown in Figures 7 to 9 in which the barrel of the key is in a position in which signals produced by the electronic key apparatus will not be transmitted to associated decoding and recognition circuitry in a security system of which the socket is a part.

FIGURE 12 shows the key socket of Figure 11 translated to a position in which optical signals provided by the key electronics may be conveyed to the decoding and recognition circuitry in a system of which the socket is a part.

Referring to the drawings an electronic key 1 comprises circuitry 3 designed to drive a light emitting diode 2 which preferably, but not necessarily, emits infra-red light. The circuitry 3 provides a predetermined digital pattern which is converted into an optical signal by the LED.

The decoding and recognition circuit 5 comprises an amplifying receiver 15 and a decoding integrated circuit 4 which decodes the optical signal and, providing that the signal is correctly defined, provides an output to a switching means 17, 9.

The electronic key I plugs into the socket ó within the vehicle in a similar manner to a conventional ignition key and ignition socket, the socket 6 providing contacts (not shown) by which power is supplied to the key I in order to effect generation of the optical signal from the kev. The optical output from the key I is coupled into an optical fibre 7 which guides the signal to the decoding and recognition circuitry 5.

The optical fibre 7 is coupled, within the decoding and recognition circuitry 5 to a receiver diode 8 which, preferably, is spectrally matched to the peak optical wavelength of the signal.

Inexpensive couplings for coupling the optical fibre to the receiver diode 8 are readily available for the polymer range of optical light guides.

In the interests of security it is preferable that the decoding and recognition circuitry 5 is located within a sealed housing (not shown), or alternatively in a part of the vehicle which has very limited accessibility, or within a sealed housing which is itself fixed in a barely accessible place, along with an essential part 21 of the protected circuit such as the ignition coil or the circuitry of the engine management unit. This further has the advantage that the appropriate component, such as the ignition coil can be produced by manufacturers within a housing wlth the decoding and recognition circuitry of the security device forming an integral part thereof.

Such a unit then lends itself to ease of replacement by a whole new unit.

The decoding and recognition circuitry further comprises an e!ectronic "latch" 9. Upon receipt of a correct signal pattern the decoding and recognition circuitry 5 provides an output voltage to the latch 9 which may comprise a thyristor, triac, or relay or other suitable "latching" component (a thyristor is shown in Figure 4 as an example). The thyristor 9 then switches power or switches enable signals through to operate essential part 21 of the protected circuit.

The electronic circuitry 3 of the key I may be energised from the vehicles own power supply by means of electrical contacts within the key socket 6 in one of three ways. Firstly the key socket 6 could be permanently powered from the vehicle's power supply. Alternatively, the socket 6 could have its power switched on by the insertion of a conventional key 22 in the conventional ignition socket 20 of the vehicle such that, as long as the key remains in the socket 20, power is available at the electronic key socket 6 to activate the electronic key I. Alternatively power may be applied to the electronic key socket 6 momentarily when the conventional ignition key 22 is advanced within the conventional socket 20 to the "start-engine" position and in such an arrangement as this the conventional key need not necessarily be removable.And lastly the electronic key socket could be powered by a separate power supply such as a cell or a battery of cells. This latter option is the least practical at this time because current battery technology at low cost would increase the size of the electronic key and socket unit and is the least reliable of the systems described above.

The coding and decoding of the signal from the electronic key is achieved by use of remote control integrated circuits.

Referring to Figure 3 the my45026 encoding integrated circuit 10 produced by SGS encodes nine inputs 26 which may be logic I, logic 0 or open circuit, and it serially transmits this information upon receipt of an enable signal.

q By use of this particular integrated circuit a possible 39 or 19,683 different unique transmit codes are possible though in practice not all of these are used.

The transmit sequence is initiated by a low level on the TE input pin and if this pin is kept low the encoding integrated circuit 10 will continously transmit the data words. Each time the TE pin is forced low, the encoding circuit 10 will transmit two identical data words. The second word is used by the receiver to reduce errors.

Each transmitted data bit is encoded as two data pulses. A logic 0 is encoded as two consecutive short pulses, a logic I by two consecutive long pulses, and an open circuit by a long pulse followed by a short pulse.

The decoding integrated circuit 4 is preferably an My45028 decoding integrated circuit but may alternatively be a M 145027 decoding integrated circuit, the M 145028 decoding integrated circuit being capable of decoding a larger number of different signal patterns.

The encoding remote control integrated circuit Ml45026 10 is provided on the electronic key I with two resistors 18 and a capacitor 19 being the only external components required to enable it to function, these components defining the basic timing speed of transmission (bit rate). The bit rate is determined by the particular resistor and capacitor combinations utilised.

It is preferable to couple a 0.! micro Farad decoupling capacitor 24 across the device power supply for decoupling purposes.

In order to prevent damage to the device by static electricity power connections which are to be brought out externally and contact made via suitable contacts are isolated by a shrouded plastic transmitter housing as shown in Figure 2.

Alternatively the integrated circuits within the key may be protected by means of reed relays 60 and the key then takes on a conventional look (see Figures 7 to 10).

The protection circuitry, an example of which is shown in Figure 10 comprises reed switches ól and two resistors (I kilo ohm) 62 connected in parallel with the key electronics, and serves to isolate the device from any external power pick up contacts which are designed for the key.

The one kilo ohm resistor shown across the power input pins ensures that any static potentials which appear between the power input pins cannot reach a high enough potential to break down the relays.

Ordinary static charges should not be able to deliver sufficient energy fast enough to sustain the voltage necessary to break down the reed switches 61.

The reed switches typically have an open circuit resistance of iso10 ohms with at least 200 volts break down voltage on each relay. By presenting possible static energy with a low impedance path through which it can dissipate the alternative high impedance path is avoided and damage to the integrated circuit is avoided.

A one kilo ohm resistor is provided on the integrated circuit side of the contacts in order to prevent damage to the integrated circuit 3 should any charge build up within the device itself, as for example if it was subjected to a strong electrostatic field.

It will be appreciated that reed switches with change over contacts, one of which could be used to short circuit the electronics, could be used instead but this could necessitate the provision of a bigger reed switch.

The reed relays may be activated in one of two alternative ways. They may be activated by a magnet when in close proximity to and during insertion into the key socket 6 or, self contained, surface mounted reed relays complete with operating coils could be used thus removing the need for activating magnets but this would necessitate slightly increasing thickness of the key housing.

By provision of reed relays the need for special moulding to shroud the power pick up section of the key is removed and the key may therefore take on a more traditional look.

Indeed combination electronic and mechanical keys each comprising a single key body could be provided which offer both electronic and mechanical operation in one key. In this way key shapes each of which is unique for its particular lock can be combined with the unique electronic signal associated with each key although with the electronic system according to the invention this is not necessary.

The advantage of using a combination mechanical and electronic key, aside from the slightly greater security involved is that such a key is, for appearances sake, less of a radical departure from the kind of keys with which the public at large is already familiar.

The keys shown in Figures 7 to 9 represent keys of a familiar construction having the electronic security device according to the invention incorporated therein.

In these diagrams the numeral 60 represents the reed relays, whilst the electronic circuitry of the key is designated 3. The positive connections provided on the keys by which they receive power from the socket are indicated at 62 and the infrared LED's are indicated at 64.

The key shown in Figure 7 has an nsulating region 65 provided adjacent the connection 62 and in the key shown in Figure 9 the positive connection 62 is fabricated witnin an insulating region (not shown).

Each of the keys shown in Figures 7 to 10 may incorporate operating coils by which the reed switches are activated or, alternatively the reed relays may be activated by permanent magnets formed in the key socket 6 so as to be activated when the key is inserted in the socket 6.

For use with combination electronic and traditional keys such as are shown in Figures 7 to 9 key socket arrangements such as are shown in Figures 11 to 13 are provided. In Figure 11 a combination traditionollelectronic key socket is shown, the socket including a barrel 70 which provides magnets 71 which activate the reed switches on the keys when an appropriate key is inserted. The barrel 70 includes an aperture 71 and which may be received a shank 66 of one of the combination keys of Figures 7 to 9, and a longitudinally extending cut away region 72 which, when the barrel is in the inoperative position does not overlie the end of the optical fibre link 7 in the socket 6. Thus the barrel 70 of the key obscures the end of the optical fibre link 7 to any optical signal from the LED 64.

An alternative arrangement, which has the advantage of leaving the key contactless involves the use of magnetic coupling, via primary transformer windings in the key socket and secondary windings in the key body which would enable power to be transferred without contacts. This would necessitate an inverter!oscilator circuit to produce alternating current from the vehicle DC battery. The resulting AC signal would then be coupled to the key via the transformer effect and it would then have to be recitifed, regulated and smoothed Whilst this arrangement removes the need for protection circuitry the number of components comprising the system is increased and consequently the potential for breakdown is somewhat increased also.Moreover this arrangement also requires a means of detecting the key when it is within the socket so as to switch on the AC signal.

When an appropriate key is inserted in the socket 6 such that the barrel 70 of the socket is enabled to rotate, say in a clockwise direction, the cut away portion 72 of the barrel is brought into juxtcposition with the end of the optical fibre 7 such that the optical fibre is then exposed to any signal from the infrared LED 64 provided on the key.

In this way entry to the optical fibre input is restricted such that it becomes accessible only when the traditional mechanical key operated lock portion is correctly operated by means of an appropriate key of unique shape.

It should be stressed that the electronic security device according to the invention can be used quite independently and in place of a traditional key and key switch as well as in combination therewith.

The output from the encoding remote control integrated circuit 10 is fed to transistor drive circuitry II which switches the light emitting diode 2 whilst ensuring there is correct phase inversion of the signal. Typical drive currents for LED are between 20 milliamps (3 millimetres size) and 100 milliamps (5 millimetres size). Optically visible light emitting diodes may be used provided that they are spectrally matched at the receiver diode 8 within the decoding and recognition circuitry 5. The use of infra-red devices may however convey a higher degree of security albeit that the user should never in normal circumstances be in a position to view the operation of the light emitting diode.

On the other hand polymer fibre transmission media have spectral characterisitics which favour the use of visible light (wavelength 400-700 nanometres) the spectral peak being approximately 665nM. Nonetheless the band width will permit of the transmission of some infrared wavelengths so that provided the optical fibre is short the invention may still be implemented using infra-red wavelengths.

Although all of the coding and decoding remote control integrated circuits will operate over a voltage range up to !8 voits it is preferable to provide the power to all of them via 5 volt regulators 27 with suitable decoupling to ensvre that they continue to operate within a constant parameter range under all vehicle load conditions. Consequently they will continue to function even with a relatively flat battery and to ensure this "low drop out" regulators should be used with appropriate decouplers.

The receiver diode 8 is incorporated within the amplifier receiver 15 which amplifies the signal before it is fed to the decoding integrated circuit 4. The output of the amplifying receiver amplifier 15 is fed directly to the decoding integrated circuit 4, the necessary links being added to the decoding integrated circuit to match the address lines of the encoding chip. An amplifying receiver known as the SD 4324 integrated circuit manufactured by Honeywell is particularly preferable but other suitable integrated circuits may be used instead.

A double sided printed circuit board with a cross matrix arrangement allows simple programming of the address pins by short circuit links but surface mount technology may be used instead if prefered. Using this technique the external components can be fabricated onto the surface of a substrate leaving the address programming to be done automatically using, for example, laser etch techniques.

A common emitter drive circuit 17, provides high current gain and hence sufficient threshold current to switch the thyristor 9 on.

Means may be provided, if desired, to indicate to a user of the article to be secured, that power has been successfully switched through to the protected circuit. For example, Figure 4 shows a lead 50 which is connected to a LED 51 on the dashboard of a vehicle which LED emits visible light.

Alternatively an optically visible LED may be provided proximate to the latch 9 and the signal may be transmitted to the dashboard by an optical fibre.

It will be appreciated that in a different embodiment of the invention the decoding and recognition circuitry may be electrically isolated from the "protected" circuitry in which case an optically coupled driver circuit may be introduced.

In a still further embodiment of the invention an ultrasonic coupling may be utilised between the electronic key and the decoding and recognition circuitry instead of an optical coupling but an optical coupling is preferred because it is less prone to external interference and offers a broader range of bit rates.

Figure 5 shows a modified starter ignition coil for a vehicle in which the security device may be employed. The coil housing 30 has permanently attached thereto at an end 31 thereof a rigid housing 32 into which pass a high tension lead 33 and twelve volt ignition wires 34. Figure 5 shows schematically the interposition of the decoding and recognition circuitry 5 by which power is switched to the coil upon reception of a correct signal via the optical fibre 36.

It will also be understood that the security device may be applied to vehicle access security as well as or rather than to vehicle starting.

By use of the technology described hereinbefore it would be possible to activate solenoids which are built into the vehicle door or door pillars in order to provide a new locking and unlocking system for vehicles. Figure 6 shows how the security device may be adapted to a vehic!e door locking system. In this Figure a key socket 50 is shown in the vehicle door 55, from which an optical fibre 51 extends to a light transmitting interface 52 at the doors edge. A receiver interface 53 is provided in the door pillar 56 opposite the interface 52 so that signals may be transmitted across the gap between the door 55 and pillar 56. A signal which is received by the interface 53 is transmitted along a further optical fibre 54 or may be fed direct to decoding and recognition circuitry 57 which, when the correct signal is received, activates a door unlocking mechanism 58.

It will be understood that the key socket 50 could be provided on the door pillar 56 rather than on the door 55 and the decoding and recognition circuitry 57 may then be provided in the door 55 rather than in the pillar 56.

Because the signal to be passed across the gap is an optical signal the system is more convenient than a wired system which would present difficulties for signal transfer.

The system also does away with the need for power operating leads which can be "hot wired".

Alternatively a waterproof membrane for the socket, styled such that it could not support moisture could be provided to adapt this system to vehicle door security and, moreover, the invention lends itself ideally to central locking.

With a security system such as has been described it should not be possible for a driver of the vehicle to lock himself or herself out of the vehicle.

If it is desired to protect more than one circuit, for example, the electronic ign;tion and the steering lock, an optical splitter or regenerator may be included in the optical pathway between the encoder key and the decoding and recognition circuitry hence giving two optical outputs.

It will also be understood that the security device according to the invention also lends itself to other security applications such as the setting of building security alarms and locking and unlocking doors. Conventionally, commercial security, whereby limited access to a building or a part of a building is required, is accomplished by such systems as PIN numbers on a key pad or a coded magnetic card. However PIN numbers can be easily overseen and cards may be easily damaged and are inconvenient for storage. Use of an electronic key according to the invention provides an alternative and improved method for both door locking and unlocking and building security alarm setting in which the control unit may be located in an inaccessible place such as a strong room and activated remotely by an optical link and can thus be set from outside a building for example.If the control unit is not accessible and/or hidden it cannot be readily disabled.

Moreover, with the security system of the instant invention the need for timing circuitry, which is currently employed in most building alarm systems, is obviated. Such circuitry gives a time delay upon entering or exiting a building to permit setting or resetting of the alarm but it also gives a would be thief time to disarm the alarm.

Setting and resetting of the security device according to the invention is also more convenient than that of traditional systems.

Where especially high security is required, for example in a bank, an electronic key according to the invention could be made part of an interactive link via a telephone line to a headquarters for example.

The key holder would have to input a code before a return signal is sent to activate the electronic key which helshe holds. In the event of the key holder being forced to unset the device against their will a distress code could be sent to the headquarters during the interactive period instead of the usual code without the knowledge of the assailant.

Furthermore the system could be used to provide secure "protected" circuits or "hybrid" circuits. For example hybrid circuits which, In the absence of a correct digital input, will not function due to a lack of power rather than because of an inhibit pin having the wrong condition on it, can be used instead of the integrated circuits already referred to. Such hybrid circuits require a decoder such as has already been described and external connections for the input diode and address pins. Such a circuit could be used, for example, as part of a car radio which would consequently be rendered inoperable in the absence of the correct input signal from, for example, an electronic key.

Moreover the security device according to the invention can be applied to T.V.'s and video recorders which have an associated remote control unit.

The digital security code could be incorporated into the remote control unit so that the T.V. or video recorder cannot be operated without the rernote control unit which is easily concealed or removed from the vicinity of the T.V. or video recorder.

It will be understood that in a similar way the security device may also be applied to computer hardware.

When applied to a starting mechanism of a vehicle it will be appreciated that the only way to subvert the system would be for the thief to carry spare ignition or vehicle management units complete with transmitters in order to steal the vehicle. This can be offset provided that the vehicle manufacturer ensures that such units are in a sufficiently inaccessible place to preclude rapid changing thereof. Furthermore if manufacturers and retailers maintain listings of new and spare ignition and management unit sales the purchase or distribution of unusually large numbers of such units would quickly be recognised. Use of the security device to disable the vehicle starting systems would remove the need for conventional ignition keys. Alternatively conventional key arrangements could be retained and/or they could be made identical for each vehicle if desired.Instead individual electronic keys and decoding circuitry for the appropriate ignition components would be provided. Electronics being relatively inexpensive, the circuitry may be cheaply and easily manufactured so that the vehicle manufacturer may make a general cost saving.

The application of the security device according to the invention to steering lock devices can be achieved by provision of a steering lock device which is activated by a solenoid with appropriate associated decoding and recognition circuitry such as has been described in relation to the vehicle ignition systern.

The security device according to the invention may also be applied to electronically controlled braking systems in vehicles and hand brake locking devices or any other suitable systems.

The features disclosed in the foregoing description, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, or a class or group of substances or compositions, as appropriate, may, separately or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims (1)

1. CLAIMS:

   I. A security device comprising a switch which is formed integrally with or in permanent securement to an article to be secured or a part thereof, said switch being operative to connect or disconnect said article to be secured from an input, which input permits of operation of or access to the article, wherein key means are provided to cause operation of the switch.

   2. A security device according to Claim I in which the switch comprises an electrical switch or an electronic switch.

   3. A security device according to Claim I in which the switch comprises a valve which controls flow of a fluid.

   4. A security device according to any one of Claims I to 3 in which the switch is positioned on said article to be secured and formed integrally therewith or secured thereto in a manner such that any attempt at access to said switch will cause irreparable damage to said article or a part thereof and!or render the article inoperable.

   5. A security device according to any one of Claims I to 4 in which the switch is permanently secured to the article and completely masks or covers any access to an input terminal or connection associated with the article.

   6. A security device according to any one of the preceding claims in which the article to be secured is a vehicle, the switch being built into one or both of either an engine computer circuit or other engine management circuit or an electronic ignition, the requirement of an input to said computer or engine management unit or ignition being essential to enable the engine to be operated.

   7. A security device according to Claim 6 in which the switch is formed integrally with a housing which is adapted to encase at least part of the ignition circuit of the vehicle such as a coil, the switch being operative to permit of, or prevent power being supplied to, the coil.

   8. A security device including key means and receiving means, the key means comprising a key part in the form of a means for generating a coded first signal and the receiving means operative to generate an output to operate a switch, said receiving means being adapted to receive the first signal which is generated by said key means.

   9. A security device according to Claim 8 in which a socket is provided in which the key means may be removably inserted, the key means, when inserted in said socket generating said first signal.

   10. A security device according to Claim 8 or Claim 9 which further comprises electronic means for decoding and recognition of the first signal, the electronic means providing, on receipt of the first signal, the output which operates the switch, operation of said switch permitting of use of or access to an article which is to be secured by means of the security device.

   II. A security device according to Claim 10 in which the decoding and recognition means is remote from the key means and key socket.

   12. A security device according to Claim 10 or Claim 11 in which a link is provided between the key socket and the decoding and recognition means for transmission of the first signal therebetween.

   13. A security device according to any one of Claims 8 to 12 in which the first signal is an ultrasonic signal.

   14. A security device according to Claim 12 in which the first signal generating means is a light emitting diode, the first signal is an optical signal, and the link is an optical fibre link.

   15. A security device according to Claim 14 in which the output from the light emitting diode falls within the infra-red band of the spectrum.

   15. A security device according to any one of Claims 8 to 15 in which the coded first signal represents a predetermined digital pattern.

   17. A security device according to any one of Claims 9 to 16 in which the key means is powered by energising means and circuitry within the article to be secured, contact points being provided within the key socket, the key part being coupled to said contact points when the key means is inserted in the socket.

   18. A security device according to Claim 17 in which the key socket is permanently powered.

   19. A security device according to Claim 17 in which power is switched on at the key socket upon insertion of a conventional key into a separate conventional key socket in the article to be secured and/or upon turning of said conventional key in said conventional socket.

   20. A security device according to any one of Claims 8 to 19 in which the key part comprises an encoding integrated circuit.

   21. A security device according to Claim 20 in which the power supply to the encoding integrated circuit is protected by means of reed relavs.

   22. A security device according to Claim 21 in which the reed relays are activated by a magnet when in close proxmity to or during insertion of the key means into the socket, the magnet being provided at the socket.

   23. A security device according to Claim 21 in which the reed relays are self contained, surface mounted reed relays having operating coils associated therewith.

   24. A security device according to any one of Claims 8 to 23 in which the key means comprises a body providing, in combination, both electronic signal encoding and emitting means and a conventional type key shank.

   25. A security device according to Claim 24 in which the key socket is so constructed as to be usable only with a key means having both electronic signal encoding and emitting means and a conventional type key shank.

   26. A security device according to Claim 25 in which the socket provides a barrel which includes both electrical contact points to which contacts on the key part are coupled when a key means is inserted in the barrel and an aperture in which may be received the shank of a key of conventional shape, insertion of a key shank of the correct shape permitting, by known mechanisms, rotation of the barrel.

   27. A security device according to Claims 24 to 26 when Claim 24 is dependent upon any one of Claims 14 to 23 and when Claims 16, 17 and 20 are dependent directiy or indirectly upon Claim 14 in which the barrel further includes, on a curved surface thereof, a longitundinally extending recess which, when the barrel is actuated to an operative position by use of a key means having a shank which is compatible with the arrangement of that particular key socket, overlies an end of the optical fibre link which is within the socket such that the optical signal generated from a light emitting diode on the key means can be transmitted via the, optical link to decoding and recognition means elsewhere in the article to be secured.

   28. A security device according to any one of Claims 10 to 27 in which the decoding and recognition means is associated, within a sealed housing andlor within a part of the article to be secured which part has very poor accessibility, with means essential to use of the article to be secured. a signal output from the decoding and recognition means being necessary to operate the switch and thereby activate the essential means and thus to permit of use of or access to the article to be secured.

   29. A security device according to any one of Claims 10 to 28 in which the article to be secured is a motor vehicle.

   30. A security device according to Claim 29 when dependent on Claim 17 in which the key is powered by at least one cell which is separate from the vehicle's conventional power supply.

   31. A security device according to any one of Claims 28 to 30 in which the essential means is any one or more of a door unlocking means, a steering wheel unlocking means which is activated by a solenoid or by electronic means, an electronic braking system, or a starter component of the vehicle such as any one or more of an ignition coil, an electronic ignition unit, an engine management unit, a starter motor, a fuel feed or a glow plug starter system.

   32. A security device according to Claim 28 in which the article to be secured is a building and the essential means comprises at least one of means to open access restricting means of the building such as a door lock or an alarm system for the building.

   33. A security device according to any one of Claims !4 to 32 in which the optical fibre link abuts against a receiver diode part of the decoding and recognition means, which receiver diode is spectrally matched to the peak optical wavelength of the signal to be transmitted.

   34. A security device according to any one of Claims 10 to 33 in which the decoding and recognition means comprises an amplifier, a decoder and an electronic latching means such as a thyristor, a triac or a relav, which latching means, upon receipt of the correct signal pattern at the decoding and recognition means transmits an output signal to the switch.

   35. A security device according to any one of Claim 10 to 34 in which the decoding and recognition means includes an integrated circuit.

   36. A means for disabling a vehicle comprising a switch which is sealed within a housing which housing also encases at least part of the ignition circuitry of the vehicle, the switch being activated by a unique, coded optical signal, to permit of ignition of the vehicle, said optical signal being transmitted by an optical coupling system which extends between the switch and a remote electronic key and socket arrangement, which key, when inserted in said socket generates the optical signal.

   37. A security device substantially as described herein with reference to the accompanying drawings.

   38. A means for disabling a vehicle substantailly as described herein with reference to the accompanying drawings.

   39. Any novel feature or combination of features disclosed herein.