WO1989002507A1

WO1989002507A1 - Security lock arrangement

Info

Publication number: WO1989002507A1
Application number: PCT/GB1988/000749
Authority: WO
Inventors: Robert Edmund Todd
Original assignee: Innovation Marketing Limited
Priority date: 1987-09-18
Filing date: 1988-09-20
Publication date: 1989-03-23
Also published as: AU2524188A

Abstract

A simple, cheap arrangement that can be easily fitted to or used in conjunction with any cheap, physically inter-matching mechanical lock and key assembly to greatly increase its security. Upon closure of the lock or an added lock an obstruction within it automatically blocks any incorrectly or uncoded attempt at reopening. The physically-matching key has a transmitter connected thereto, and when inserted in the lock, and its connected transmitter activated, passes a coded identifying signal using the key as conductor into the lock which has a connected receiver/control unit. The person holding the key cap completes the circuit by capacitance and/or fringing effects so that a conventional metallic key without special modification can be employed. Only if the signal received matches the programme pre-set within the receiver unit, does the latter activate the obstruction-removing circuit, and the lock can be opened by the key. The concept can be realised in other ways, acting on other functions within the lock or, say, a protected circuit, or inhibiting its use in any sphere where anything has to be restricted in its use. Its power may come in any suitable form as may its signal.

Description

Security Lock Arrangement

This invention relates to security control devices, particularly but not exclusively security lock arrangements and in one embodiment provides a small, econo ical and easily installed conversion kit (comprising of two inter-relating assemblies) , which when one part is fitted to a normally available, conventional type of mechanical or similar device lock and the other part is connected to the conventional, mechanical type of key, greatly increases, at a fraction of the cost, the security of said conventional lock to the standards of the more secure, complex and expensive electronic high security type of lock. Such a kit may be retro- fitted to an existing lock with minor or no modifications. In a second embodiment the device may comprise a separate lock operated electronically by the same key or pther device so that the electronic lock and mechanical lock must be operated before access can be gained.

Key operated security systems for e.g. motor vehicles, houses, factories, safes and hotels are normally mechanical , and, although there are a great many varieties, all are fundamentally similar in design, operation and manufacture. It is a restriction of the design and manufacture of these locks that presents their biggest weakne sse s . Firstly, as mechanical devices with access to their internal workings, they can be "picked" ; secondly, the design restrictions of- a compact key and lock system severely restricts the number of "combinations" available to the manufacturer. Compounding this there is the effect of manufacturing tolerances and wear and tear of the "keying elements", which when compounded up, greatly restrict the number of really true distinct combinations available to the end user. In order to improve the levels of security available in the market, various types of "electronic locks" have been introduced, but these also have their own disadvantages, namely that a completely new lock has to be purchase , whose type of key is un- familiar and sometimes less robust; they are thus much more expensive than a conventional, mechanical type of lock and often undesirable in the market-place.

One known system uses a magnetic bar-coded key, which is read as it is entered into the lock, and, if the coding is correct, the door can be unlocked by turning the key. This system is liable to accidental erasure by electrical noise etc as in cars and industrial areas, is un- familiar in appearance and extremely expensive to pro uce, and as it is a "complete" lock, it is expensive to install and maintain.

Other known systems use "multiple contact arrangements" which allow the key to communicate a code to a master unit to allow access past the lock. The drawbacks of these systems are that the key and barrel, although familiar in appearance are in fact very complex arrangements of electrical contacts which are subject to wear, ingress of dirt or moisture , damage to the lock if attempted to be picked with a metallic or conductive implement, and damage by freezing etc. They all need a system of wires from the contacts/de-coders in the barrels to the main control unit, which can be damaged by extremes of temperature, thus rendering the systems either useless by removing the locking action of the circuit, or dangerous in a fire situation by rendering the lock unopenable. These systems are also severely restricted in their use in, say, the automotive industry, as the added cost of the required harnessing and installation are prohibitive. Others have multiple electronic circuits, each with its own independent tracking or terminal , along the key body. Such systems are incompatible with external use where the elements may directly or by corrosion or tarnishing adversly affect, or corrupt the information or at worst destroy part or all of the exposed circuitry. This situation would be made worse by the action of inserting the key or other metallic object in the lock as this action alone would draw water or contaminants into the lock and cause abrasion and or failure of the system by short circuiting. Any means of avoiding this problem would inevitably lead to the product cost and complexity both increasing unnecessarily, or at least greatly increasing the maintenance requirement of the system.

Other systems have multiple electronic circuits, each with its own independent tracking or terminal on the key body. Such keys may, at unwanted times, be inoperative in outdoor conditions, as rain water may be picked up during insertion into the outer lock ^' of e.g. a building or vehicle and could spread over the body of the key thus destroying the integrity of the signal circuitry, rendering the system temporarily useless, even to the authorised user. This severely restricts the applications to which such a system could be put thus reducing the effective protection available in general, whilst certain systems can be adapted to overcome this their cost escalates, as does the complexity and maintenance required by such systems.

Examples of the types of security locks described above are set forth in the following patent specifications; U.K. Patent Application No. 2172928A; U.K. Patent 1,294,991; U.K. Patent No. 1,401,281; U.K. Patent Application No. 2073808A; PCT Patent Application No. W084/04128; U.K. Patent Application No. 2085064A; PCT Patent Application No. W083/00976.

Clearly it would be desirable to have a key-operated system combining the cheapness of a conventional mechanical lock and the higher security of the electronic lock, without the disadvantages of the complexity and cost of such existing systems.

The present invention aims at providing a security lock arrangement which overcomes these disadvantages but it has been found that the invention in at least some of its aspects, as explained herein, has much wider security control applications.

According to the invention in a first aspect, there is provided a security control arrangement comprising a coded signal transmitter, a coded signal receiver , a first electrically conductive means connected .to the transmitter to fo.rm a first unit and a second electrically conductive --means connected to the receiver to form a second unit, said first and second conductive means normally being out of ' electrical coupling, but which when in electrical coupling , permit a coded signal to be transmitted from the transmitter to the receiver through said first and second conductive means, and inhibiting means under the control of the receiver permitting release of said inhibiting means when the correct coded signal is received by the receiver, and wherein of said first and second units one is portable and when held in the hand with said first and second conductive means in electrical coupling the person holding said one unit completes a circuit ena-bling the coded signal to be sent to the receiver.

By "electrical coupling" as used herein is meant physical, mechanical or electrical contact as opposed to the coupling by means of signals which are transmitted through space.

By means of the invention the portable unit conductive means may compr ise a simple metallic member, more usually a key for a mechanical lock, and there is no requirement to provide a special electronic key or a key with independent tracking or terminals, or multiple ^'contact arrangements.

Such arrangement clearly can be used for controlling mechanical locks as the first and second conductive means may be the lock and key, but clearly the concept has much wider application and could be used for example for security checking by identification and recording data. For example each person whose movements are to be recorded could be provided with a transmitter and connected conductive element and a record of the time and date when he electrically coupled with the second conductive means could be easily made. The arrangement can be used for employee time keeping monitoring, or a person purchasing goods, for example.

Also, the invention provides a security lock arrangement comprising a mechanical lock and a key therefor controlling an access, said key being for operating the lock by insertion thereon followed by manipulation of the key, a coded signal transmitter, a coded signal receiver, a first electrically conductive means connected to the transmitter and a second electrically conductive means connected to the receiver, said first and second conductive means normally being out of electrical coupling, but which when in electrical coupling , preferably by contact, permit a coded signal to be transmitted from the transmitter to the receiver through said first and second conductive means, and inhibiting means under the control of the receiver permitting release of said inhibiting means and said access to be gained by Operation of the lock and key only when the correct coded signal is received by the receiver, and wherein at least one of said first and second conductors comprises said lock or said key.

The said inhibiting means may be a means acting upon the said mechanical lock, or it may comprise a separate electrically controlled lock also acting as a lock in respect of said access.

In a third aspe.ct the .invention provides a security lock arrangement comprising a key operated mechanical lock and key in combination with an electronic security system comprising a transmitter for transmitting a coded electrical signal and a receiver for detecting the receipt of such signal or detecting its absence-, said mechanical lock and key being coupled b.y inhibiting means preventing or causing operation the means controlled by the mechanical lock and key only when the receiver has detected the presence or absence of said signal, and wherein said transmitter is electrically connected to the key and the receiver is electrically connected to the lock so that said signal is transmitted by electrical coupling between the key and lock.

Preferably in all^* aspects of the invention the operation of the device will depend upon the holding of the key and transmitter by the person wishing to operate the device, and that such person forms a part of the signal loop enabling the coded signal to be passed to the receiver. The person may thus form an antenna and the receiver may form an aerial for "fringing" signals from the person and/or the signals from the person to the receiver may be by capacitance coupling to ground or via ground.

By the present invention at least in some embodiments there can be provided a cheap, simple, two-part kit of transmitter and^' receiver with inhibiting means which can be fitted by a non-specialist , either to a cheap, conventional, readily available (or existing) lock-and- key system, with minor or no modifications being required to the existing mechanical lock and key or can be fitted as a separate electronic lock. There may be no^' need to dispose of the existing mechanical lock, and merely fitting the "conversion" will up-date it into a high-security electronic locking device, which is totally familiar in appearance and operation; it need have no reading unit in the barrels, no complex contact arrangements in the barrels or key, and no need to have wiring in the close proximity of the barrels. ^'When provided as a separate lock operated by the signal from the key, it may release a lock bolt which may be of the spring loaded or dead bolt type. When the bolt is withdrawn , the key can then be used to operate the existing mechanical lock. In such case the mechanical lock and electronic lock may control the same function so that both locks must be operated before the function can be performed or the electronic lock may control a separate security function.

The inhibiting means may have a "sleep" or out of use position which can be selected manually so that as required the lock can be used normally when high security is not required.

The transmitter preferably is in the form of a "cap" which merely fits over the head, (BOW) of the existing mechanical key, possibly comprising a battery, a code- retaining and transmitting circuit with, if required, a switching means to activate the transmission of the cocfe through a contact into the bow of the key; the switching medium may be a button operated by pressing the key to the lock, or a sensor which can detect it is being held by the user.

The receiver may be linked to any metallic or conducting part of the lock-mechanism or (in the case of a motor vehicle) any part of the body-work, chassis or engine. The receiver may comprise a de-coding unit which receives the code transmitted by the transmitter, examines the code and either accepts or rejects the code of that particular key, (bear in mind that the mechanical code of the key has also to be correct to complete the access operation) . If the electronic code is correct, the receiver may operate a solenoid to remove a blockage , such as a latch device which may have been automatically applied upon closure of the lock, to permit conventional mechanical movements of the components of the lock or operate the separate lock or other_* means.

A solenoid or -other means such as a motor may place a blocking element in the path of movement of the conventional locking components of the lock or move a bolt of the separate lock on receipt of the wrong code or no code at all, and it may also activate an integral alarm, or trigger an exist ing remote alarm if so desired when such conditions prevail. Thus, there may be provided a system which, when added to or used with a conventional lock with minimal installation requirements, greatly improves security, as not only is the mechanical keying requirement present, but a new and infinitely variably codeable electronic requirement has to be met prior to access being gained.

The arrangement can be modified to suit many various requirements; it can for example be set so that it is operative only when trying to open the door, so that power is not required to be applied at all times; it can be fitted to or used with any type of conventional mechanical locking system; it can have different levels of access, thus reducing the number of required keys in say an industrial environment. For example all of the locks in a factory could_^ require only one mechanical configuration of the key; say there are ten locks, all of which require the same mechanical key, but coded key A, may open all ten locks, coded key B, may open locks 4, 7 and 8, coded key C, may open 1, 2, 3 and 5 and so on; the advantages of such a system are apparent to those skilled in the art. Another feature that may be incorporated is a power- supply warning device; the receiver and/or transmitter may be powered by a small battery (which can form the aerial) inside or near the lock, and it may be desirable to have advance warning in the event of its imminent failure.

The type and location of the power source or sources is of no importance to the system, as this or these would be conveniently provided to suit the chosen application. For example, the transmitter may be powered from the battery of the receiver as a result of bringing the first and second conductive means into electrical coupling. The blocking of the mechanical lock or operation of the se arate lock by the electronic unit can also be varied to suit the particular application. The response of the electronic unit can be held open for a period of time to allow the key-user time to open the mechanical lock comfortably without having to ensure a constant transmission of the signal from the key to the de-coding unit throughout the key rotation; this minimises the requirements on the electrical conductivity and thus minimises its complexity, cost and power demand whilst aiding its inherently high reliability. It is felt that the system could run for several years without requiring a change of batteries (if this is the chosen medium to supply the power) as the majority of the locking and unlocking effort will still be made by the key user, when turning the key in the conventional manner. In any case the battery may be charged by means of a photo electric cell αr mechanical generator.

This system can also control devices other than locks. In an automobile it may immobilise the ignition or starter until the correct code is transmitted into the main unit; it may control an alarm; it may control lights or switches; it may do all of these without the need to connect wiring from the main unit to the key barrel, or any physical changes in the design of the key and the barrel.

Many other electronic features can be incorporated in order to defeat an attempt at unauthorised entry. Although these are not in themselves novel, the outlined system is perfectly suitable to have any electronic feature incorporated within it. It may alternatively be incorporated into another existing alarm circuit and be used to provide a trigger or cancelling effect_ on said circuit.

The system can be adapted to the more complex requirements of specific families of lock. An example of a lock with set requirements other than pure locking is a hotel lock, which has to be a "stand alone" unit, i.e. it has to have its own power source, it has to lock the bolt only when the wrong key code or no code is presented to it, the bolt must be free to withdraw when the door is closed to allow the door to self-shut, and the door must at all times be able to be opened from the inside by turning the knob, which is to allow free exit in the event of an emergency such as a fire. It is also de sirable to be able to change the code required by the lock in the event of someone taking the key away with them, and it is also desirable to know, say, the last fifteen key codes that were authorised and used to gain access through the door.

All of these requirements can be accommodated by embodiments of the invention, for example. The key is modified by the addition of the electronic key coding cap, which may have a volatile memory to allow the codes to be changed; it may also have an extra code set into it which tells the main unit in the door to ignore the present code and accept the code it is about to be given, and it will then treat this code as the correct code until it is told otherwise . The extra code may only be used once and may be automatically removed once the main unit ^■ has read it and responded accordingly, thus the code the lock is looking for can be changed eas.ily without the need for specialist equipment being brought to the door; this re-learn facility can be used time and time again. The do-or knob would then have a switch set into it to allow it to know whether the door is being opened by the knob or being slammed shut, or being opened by a key; this switch would be operated by measuring the "slack" in the internal locking system of the door, as it is possible to detect the means of operation with this technique. As an alternative this measuring is effected by monitoring the electrical characteristics of the lock, which change as any contact is made. Specifically, the change in capacitance characteristics is detected. If the door is slaπfmed shut, or the knob inside the room is being used, the switch contacts remain open and the circuit is broken, thus the obstructing solenoid is deprived of power and cannot block the lock's operation. If a key other than the correct key is used, as it turns (it is on the opposite side of the door hence its relative effect on the slack in the lock is equal and opposite to before) the switch contacts close, the obstruction is introduced, and the door self-locks. If the correct key is used the coded message is recognised and stored in the memory (if different from those already in the memory), it then cuts the power supply to the switch so that even when the switch closes there is no power there to introduce the obstruction to the lock, and access is granted. This unit is more than capable of being supported by a conventional PP3 type of 9 volt battery, (for example) for a period of time running into some years. The key can be re-coded an infinite number of times by a portable prog ramming device possibly kept at the hotel reception. It is thus a significant improvement on existing types of mechanical lock, and is equal in function to a high security electronic lock but at a fraction of the cost and can be installed with _^consumate ease.

It is envisaged that this electronic locking device would become available in various guises, firstly as a complete lock and electronic assembly , second as a conversion kit to a customers existing conventional style of lock, and thirdly as a separate electronic lock to be fitted to say a door already provided with a mechanical lock; each would have the same type of electronic assembles. The key coding caps can be made to fit onto the key bows of all the ajor manufacturers' keys, the main unit will be the same for all standard , non-spec ialised locks, while the electrical blocking device will fit into adaptor kits to make it fit any manufacturers ' lock, or it may comprise a separate lock and finally, there may be a cover plate to seal off the hole that may be drilled into the door into which the main unit and power supply may be fitted. It is envisaged that, when the device has been installed, it is the first correct mechanical key (with coded cap fitted) to be inserted into the barrel after the battery has been connected that will be accepted, until either the battery is disconnected which wipes out the memory, or the wipe-out command is received (depending on the chosen application) .

The main embodiments of the present invention have the advantage that transmission of the coded signal is achieved by electrical coupling specifically electrical contact between two components which typically comprise a lock and the standard key for operating that lock. It is possible however in other embodiments of the invention to provide that the transmitter is connected simply to a conductive member which may for example be arranged to contact the lock or some other conductive or trans issive part such as wood, paint and/or^' varnish in order to activate the receiver.; The _. receiver can either be connected to a latching mechanism^' inhibiting the operation of the lock until a correct code is received, or it can be connected to some other controllable means such as a separate lock, or relay contacts in an ignition circuit so that the ignition circuit is not enabled until the receiver has received the correct coded signal from the transmitter.

By virtue of the invention, a security lock arrangement can be effectively controlled to make it more secure in that transmission of a coded signal is required before the lock can be operated . The transmission of the coded signal is achieved by the electrical coupling, conductive and/or capac it ive , between conductor components, and particularly the components preferably comprise the lock and the key for operating the lock and fringing between the person holding the key and the lock, and in a particularly advantageous embodiment of the invention the lock and key are standard mechanical lock and key components.

The invention at least in its preferred embodiments, provides the significant advantage that no special modification to a door through which access is required has to be made in order to effect the coupling between the transmitter and receiver, nor is any special modification of the key and lock required to effect this transmission of the signal, because the signal loop is completed by coupling through the person holding the key. If an optical coupling arrangement is provided, then it is necessary to provide an appropriate aperture for receipt of the optical sensor, such aperture being provided in the door or door frame, whereas if the conventional methods are used for transmitting the signal through the key and lock, a special lock is 'required , and the key is required specifically to have multiple circuit contacts.

Embodime nt s of the present invention will now be described, by way of example, with reference to^' the accompanying drawings wherein:-

Figs. 1 and 2 are side views of standard mechanical keys with transmitter caps fitted;

Fig. 3 is a diagrammatic sectional plan to an enlarged scale of the key shown in Fig. 1;

Figs. 4, 5 and 6 are diagrammatic side views of a lock and latch mechanism in different operational sections;

Fig. 6A is a partial side view of a door which is provided with a security lock system according to the invention; Fig. 6B is a sectional elevation of an electrically controlled door lock shown in Fig. 6A;

Fig. 7 is a diagr ammat ic view illustrating the principle of operation of the embodiment of the invention ;

Fig. 7A is a view similar to Fig. 7, but shows how the embodiment of the inventions of Figs. 6A and 6B operates;

Figs. 8 and 9 are circuit diagrams respectively illustrating one embodiment of the receiver and transmitter of the invention; and

Figs. 10 to 15 show six alternative embodiments of the invention.

Re erring to the drawings, the keys of Figs. .1 and 2 are provided with a transmitter cap capable of releasing a coded electronic signal (which may simply be a frequency signal) via electrical c ntact (touching) with the body (BOW) of the key. This signal is picked up from any metallic component of the lock assembly when contacted by the key by a receiver which then analyses the coded signal and responds accordingly; such response may be in the form of the controlling of an electromechanical device which in one position may block the mechanical bolt of a lock operable by the key, while in the other position it may allow the bolt to travel freely (subject to the other mechanical requirements being met). This system may "stand alone", and could be powered by a battery.

Referring in more detail to Fig. 3, the metal key 1 is inserted into cap 2, and is held in place by the cap's narrowness or by adhesive, clips or the like. A lithium type of button cell battery 3, is held into the cap by a button 4. This button is further held in place by retaining clips 5, while the base of the battery may be held away from its contact by an insulating sponge ring 6. When the button is depressed , it compresses the sponge ring and the battery makes contact with its electrical contact 7, thus energising the code- transmitting circuit 8, which sends its pre-set signal into the metallic key via terminal 9, from where it is picked up by mechanical and electrical contact with the lock when the key is inserted into the lock socket.

Fig. 4 shows in cross-section, the lock in a part- closed position. The key 1, has been inserted into its housing within the lock, and its mechanical "keying" is correctly matched with that of the barrel, which will allow the key and inner barrel to rotate, pushing the lock bolt 10 outwards into the door-frame recess. In this example a lock-bolt is show.n which has various recesses II and 12 along its length, of which recesses 12 is in use. If no notch is available either a notch could be put in or an alternative means of blocking can be established, but this is entirely dependent on the application chosen and the lock type in use. I-n Fig. 4, the top recess is unused and empty. The solenoid type of obstructor unit 13, being in .a static position relative to the lo ck- ca s ing and mechanically independent of the lock-bolt , being fitted onto the lock body, has an arm 14, which is permanently pressed by a spring against lock-bolt 10.

Fig. 5 shows in. cross-section the lock with its bolt protruding to its maximum throw. Recess 12 is now level with peg 15 on the end of the arm 14 and this peg has been driven by the unit spring into the recess 12, holding the bolt in the lock-closed position as long as this peg is held there. Fig. 6, shows in cross-section the lock with its bolt still at maximum throw. The key 1 has been inserted in the lock and the power source 3 has been depressed , connecting the base of 4 to terminal 7, thus energising the transmitter which transmits the coded signal through the key 1 and into the lock from where it is transmitted to the receiver 16, where the code is examined, and compared. If it is correct, it connects the power source.17 to the solenoid 13, raising the obstruction peg 15 out of the recess 12, thus freeing the lock bolt 10 so that it can be withdrawn by the mechanical action of turning the key 1, in the barrel, and so _* allowing the lock to be opened.

Referring to the arrangement shown in Figs. 6A and 6B, a door 10X is closable against a door frame 12X, and the door 10X carries in this embodiment a conventional yale lock 14X having a key slot 16X. , The yale lock has a door locking bolt 18X, and operation of the lock 14X is by the insertion of the key 20X into the slot 16X followed by the turning of the key which retracts the bolt 18X and would normally allow opening of the door. However, in accordance with the present invention a second door lock 22X with its own door bolt 24X engaging the door frame is provided, and that bolt must be retracted before the door can be opened. This is achieved in accordance with this embodiment of the invention in that the control signal from the cap 26X and the key, which is similar to cap 2 in the embodiment already described , signals to a control device in lock 22X to retract the bolt 24X assuming that the cap 26X sends the correct signal as described hereinbefore.

The electrical coupling between the cap 26X and the lock 22X is described in more detail in relation to Fig. 7 A. In Fig. 6B , the lock 22X is shown in greater detail. The lock bolt 24X is contained in a housing 30X so as to be slidable therein. A threaded bore in the bolt 24X contains a threaded drive shaft 32X. At the end of the casing 30X inwardly of the door frame the threaded shaft 32X has a worm wheel 34X which is drivingly engaged by a worm wheel 36X coupled through a dog clutch 38X to a drive motor 40X which is electric in nature, and whose operation is controlled dependent upon the receipt of a control signal from the cap 26X. If the signal transmitted from the cap 26X is the correct one, motor 40X is driven so as to retract the bolt 24X from the position shown in Fig. 6A to the position shown in Fig. 6B, and operation of the motor is terminated when a contact block 42X carried by the bolt 24X contacts a limit switch or contact device, and rotation of the- moto^'t stops.

As long as the door is open, a spring loaded door sensor 42X projects from the edge of the door, but upon closing the door, the inward projection of the sensor 42X operates a limit switch 44X which causes the motor 40X to reverse rotate, and to drive the bolt 24X to the door closing position whereby the door becomes double locked by the yale lock 14X and the control lock 22X. The advancing movement of the bolt 24X to the door locking position as shown in Fig. 6A is limited by a further limit switch contact.

The lock 22X is provided with a sleep switch 46X which is such as to render to motor 40X inoperative regardless of any signal received from key 20X. Switch 46X is manually operable between a "sleep" position and a "non-sleep position" so that the person who has right of access through the door can render the security lock 22X inoperative during periods when high security is not required. It can be seen therefore that to fit the arrangement of Fig. 6A, it is required only to provide an appropriate recess in the door to receive the additional lock 22X, and no further modification of the door is necessary although a path of electrical contact between the lock 14X and the lock 22X should be provided.

In an alternative key arrangement , instead of using a displaceable button 4 in the housing 2, the cap may be constructed so that conduction and the sending of the signal is established simply by the user holding the cap and key in his hand, or by pressing it into the lock, the electrical circuit from the cap being completed through the person holding the key to earth.

Also, instead of the receiver unit being housed in a door or door frame, which is one embodiment as envisaged, it is possible to simply make the receiver unit as a self-contained assembly for attachment to a door.

The transmitter may be arranged in fact to code the receiver when the- receiver has a memory which when blank can be coded by the first signal it receives. The receiver memory may be capable of being wiped clean either by operation of a wipe-clean switch or the like, or if the receiver is powered by batteries, the memory may be wiped clean by disconnecting the batteries.

In a particularly suitable arrangement for a code for operating the electronic part of the lock, the code is made up of two groups of information, a first group and a second group. This information will be digital, and for convenience is referred to as A and B. The receiver is therefore set to recognise A and B in order to effect opening of the electronic lock, but for added facility for changing the code, the receiver may be set to recognise the second part of the information B whether in the first position or in the second position. But when B is in the first position, it is set to refuse to recognise B and A. The advantage of this arrangement is that changing of the code can be effected quite simply. Thus, if the receiver is set to recognise A and B it will operate as long as the key presents the code A and B, and no other except a code of which the first part is B, and the second part is not A, and when it recognises a code of which the first part is B, and the second part is say C, the receiver will have been rep rog rammed only to operate on recognising B, C or C as the first part of a two-part code of which the second part is not A or B, and so on. By this arrangement it becomes simple for the code of the receiver to be changed by appropriately coding keys which subsequently are to be used for gaining access to the same area. This is particularly useful in relation to 'coded keys for hotel bedrooms as a first guest may be given a key with the code A, B and he will use that key as long as he is resident at the hotel, but a second customer may be given a key with the code B, C for the same room and when he presents that key to the lock, he will gain access and the hotel room lock will be recoded specifically to his key, and it is not necessary for the hotel personnel to make any special coding alterations to the hotel door lock.

Fig. 7 shows diagrammatically the arrangement by which the embodiment of the invention described in Figs. 4 to 6 operates. A door 20 is provided with a lock 21 of the type illustrated in Figs. 4, 5 and 6, and the holder 22 of the key 1 touches the lock 21 with the key 1 thereby to establish electrical contact between the key and lock. The transmitter cap 2 transmits a coded signal cαnductively through the lock and key to the receiver 16 as described herein, and, at the same time, the person 22 in fact acts as a coupling element in the form of either an antenna emitting fringing signals 23 corresponding to the coded signal forwarded by conduction and these fringing signals are picked up by the battery 17 acting as an aerial, or in the alternative, depending upon the environment and conditions, the .signal through the person ^'22 is picked up capacitively as indicated by reference 24, by the battery 17. In either case, or by receipt of a signal which is a combination of both modes of transmission, the receiver 16 in addition to receiving the signal conductively through the lock and key, also receives the signal by a coupling effect so that the receiver can operate in a de-coding fashion in order correctly to identify the key 1 or indeed to prevent unlocking of the latch mechanism 10, 13 and 15 in the event that the wrong key 1 is placed in the ipck 21.

In the- arrangement shown in Fig. 7A, the person 10Y wishing to gain access through the door 11Y presents the key 12Y having the cap 14Y with the appropriate coded signal eminating therefrom. When the key 12Y touches the conventional lock 16Y, a coupling circuit is completed by fringing and/or capacitance to the battery 24Y of the receiver, and the second electronic lock 26Y, which corresponds to lock 22X in Fig. 6A is operated allowing eventual access through the door 11Y when the conventional key 12Y is inserted completely into lock 16Y and is turned.

Figs. 8 and 9 show the circuit diagrams of the receiver and transmitter respectively. In Fig. 8, the battery 17 is shown, and it is connected between a zero volts ground line 19 and positive volts line 25. An RC circuit 26 is connected between these lines 24 and 25, and is coupled as shown to a phase loop lock circuit 27 which is driven by means of a transistor 28 which is operational when it receives the input signal by conduction from the key 1 through input line 29. The coupling signal through the person 22 is experienced by the ground line 19 via battery and is applied to the phase lock loop circuit 27 A and compared with a reference from the RC circuit 26. When the circuit 27 detects the correct coded signal, the appropriate output is given on line 30 for the operation of the release of the latch mechanism or the motor 40X as described herein.

The transmitter circuit as shown in Fig. 9 comprises the battery 3 and the switch 6, 7 connected between a zero volts ground line 31 and positive volts line 32, across which is also connected an RC circuit 33 which matches the RC circuit 26 (Fig. &) . A conventional timer processor unit 34 is embodied in this example in order to provide a square wave output signal of a predetermined frequency, and the output square wave is applied on line 35 which is in fact connected to contact 9 as shown - in Fig. 3. Output line 35 is connected to line 29 in Fig. 8 when electrical contact between the key and lock as described herein is established.

The matching of the RC circuits 26 and 33 and the capacitance and/or fringing coupling between the transmitter and receiver, which is via the ground lines 19 and 31, enables the completion of the circuitry for the checking of the code emitted by the transmitter, by the receiver in order to provide an output on line JO when there is a match between the programming of the receiver and the transmitted signal.

It can be seen that by this method of connection, many possibilities of application of the invention are possible , and the invention is not to be considered as limited to a mechanical lock and key arrangement . Also, it is not strictly necessary that the person with the key should place the key in the lock, as it is possible to trigger the receiver from a distance as long as the conductive and capacitance or fringing coupling can be established.

The receiver may be coupled for example to a memory bank for simply inserting information, for example information as to when the person has made conductive and coupling contact with the receiver.

A number of possible modifications and manifestations of the embodiment of the invention already described are possible , and several arrangements are shown in Figs. 10 to 15.

In the arrangement of Fig. 10, the key 100 is adapted to fit into a lock 102 in a door.104. The key 100 is provided with a transmitter cap 106 as described, and the insertion of the key 100 in the lock 102 establishes the electrical connection between the transmitter 106 and a receiver 108. The receiver 108 operates an inhibiting means such as a latch 110 to allow the lock 102 to be operated by turning of the key 100. The arrangement of Fig. 10 is. essentially similar to the arrangement described with reference to the earlier figures.

In the arrangement of Fig. 11, the receiver 108 operates an inhibiting means 110 which is not operational on the lock 102, but for example is operational on some other component to be controlled, for example the coil of an ignition circuit of a motor vehicle. All other parts having the same references as in relation to Fig. 1 have the same function , and indeed this applies to all of Figures 10 to 15. In the arrangement of Fig. 12, the key 100 with its transmitter 106 is adapted to make electrical contact with a part of the system or equipment which is remote from the lock 102. For example if the mounting door or panel 103 is metallic, the signal can be sent from the key through the door 103 to the receiver 108. Again the receiver 108 controls the inhibiting means 110 which inhibits the lock 102 from being operated unless the correct coded signal is transmitted from the key to the receiver.

In the arrangement of Fig. 13, the transmitter 106 is in fact carried by a separate conductive element 112, and to enable the lock 102 to be operated, the element 112 is electrically connected by contact to the receiver 108 to permit operation of the inhibiting means 110. Thus a person wishing to gain access by opening of the lock 102 requires to have the transmitter and conductive member 112 on the one hand, and ^'the key 100 on the other hand.

Fig. 14 shows the arrangement where the conductive member 112 has to contact the lock 102 for the sending of the signal, -whilst Fig. 15 shows the arrangement wherein the receiver 108 has the inhibiting means 110 not connected to the lock 102 but to some other device to be controlled such as the coil of a motor vehicle ignition circuit.

It can be understood therefore that there are many possible variations of the subject matter of the present invention , and it is also to be pointed out that when the receiver receives the correct code from the key or other conductive member, there will be sufficient time to enable the key to be turned in order to operate the lock or ignition circuit or whatever means has to be controlled by the turning of the key in the lock, but this can be achieved relatively simply by incorporating a delay means in the operation of the receiver 108 to ensure that when the inhibiting means 110 is operated , it will remain operated for a predetermined period which may be varied to suit various needs as in the case of disabled operators.

For added security, the operation of the inhibiting means may require the receipt of signals from two or more coded keys or other members which have to be electrically coupled in sequence and in a predetermined time period to the receiver.

In any of the arrangements described, it is possible to provide that if any attempt is made to operate the lock, wherein the correct transmitter signal is not applied to the _t receiver , then an alarm system can be actuated. Such alarm system may include an alarm located adjacent the lock, or remote from the lock.

Although the invention in order to function requires a transmitter and a receiver with conductive elements, it is also- to be pointed out that the present invention provides a novel form of transmitter cap for a key and any of the various individual components of the system can be considered as being an invention in itself and the right to claim protection therefore is reserved herein.

The invention in its various embodiments has a number of advantages including the following:-

A simple, economical , easily fitted electronic con version ki t which may be fi t ted to an existing conventional mechanical lock and key assembly, providing a vast improvement in the security of the lock and key to which it is fitted is provided in a simple manner, in that no alteration of the door is required for the transmission of the signal between transmitter and receiver by virtue of the fringing coupling method;

Any type of transmittable signal may be used;

Control by the key may not be upon the lock as an electronic lock in its own right, but upon an electronically controlled additional lock.

Codeable electronic security is provided without using an electronic lock;

Security re-keying does not necessitate the replacement of the lock or parts of it;

Electronic security is provided at only the fraction of the cost of a fully electronic conventional system;

Electronic additions are made to a conventional non¬ electronic key and completion of the control circuit is through the person holding the key;

Electronic additions are made to a non-electronic lock- assembly;

The key to be adapted may be of any cheap non¬ electronic mechanical type;

The lock assembly to be adapted may be of any cheap non-electronic mechanical type;

A mechanical lock may be modified in one function only, e.g. the electronic code may only be required to unlock the system, with the blocking device only acting on the unlocking function of the lock; Only the correct combination of the correct mechanical key and the correctly coded transmitting coded-cap will operate the lock;

At or near the point of either or all of the extremes of the throw of the bolt an obstruction can be introduced to the bolt /bolts to inhibit its movement to provide a secondary level of security to an otherwise conventional lock;

An identifying code can be transmitted into a key;

An identifying code can be transmitted into a non¬ electronic, mechanically matching lock assembly;

A receiver unit connected to the lock can examine the signal transmitted into the lock by a suitably modified key, and if such a signal matches the pre-set signal within the receiving unit a release mechanism can be operated to allo'w the lock to be operated in its original fashion;

Attempted operation of the bolt with a mechanically correct but non-electronic or incorrectly coded key will not be successful;

The transmitter and receiver may be so designed so that the only time the higher power requirement of the blocking solenoid is present is when the "WRONG" key is being used;

The receiving unit does not need to be near to the key or the lock;

The receiving unit does not need to be linked via wires or contacts to the key barrel, and only one contact is required and this can be taken from any part of the conventional lock assembly;

The coded message may be transmitted from the key by radio or other means to interface with a conventional lock;

The lock may be pre-set to operate at only specific times on specific dates;

The output from the kit can have a delay incorporated prior to its response being carried out;

The output of the kit can be held for a period of time to facilitate the operation of its associated components from the user's point of view;

Any physically-matching key may close the lock, and such a physically-matching key may use no electrical power when closing the lock.

Claims

1. A security control arrangement comprising a coded signal transmitter, a coded signal receiver, a first electrically conductive means connected to the transmi tter to form a first unit and a second electrically conductive means connected to the receiver to form a second unit, said first and s^'econd conductive means normally being out of electrical coupling , but which when in electrical coupling , permit a coded signal to be transmitted from the transmitter to the receiver through said first and second conductive means, and inhibiting means under the control of the receiver permitting release of said inhibiting means when the correct coded signal is received by the receiver , and wherein of said first and second units

, one -is portable and when held in the hand with said first and second conductive means in electrical coupling the person holding said one unit completes a circuit enabling the coded signal to be sent to the receiver.

2. A security lock system comprising a mechanical lock and key controlling an access, an inhibiting means either controlling the operation of the mechanical lock or also controlling said access, a receiver operatively connected to said inhibiting means for controlling the operation of same, a transmitter operatively connected to a conductive member which may be said key o? another member to form a hand held portable unit, said portable unit when held by a user in a position establishing electrical coupling between the conductive member and the receiver, serving to transmit a coded signal from the transmitter to the receiver and the person holding the portable unit completes the circuit so that if the coded signal identified by the receiver is correct, the receiver operates the inhibiting means enabling the user provided he is in possession of said key to gain said access.

3. A security lock arrangement comprising a mechanical lock and a key therefor said key being for operating the lock by insertion therein followed by manipulation of the key, a coded signal transmitter, a coded signal receiver , a first electrically conductive means connected to the transmitter and a second electrically conductive means connected to the receiver, said first and second conductive means normally being out of contact, but which when in electrical contact, permit a coded signal to be transmitted from the transmitter to the receiver through said first and second conductive means, and inhibiting means under the control of the receiver permitting release of said inhibiting means and the lock and key to perform its function only when the correct coded signal is received by the receiver, and wherein at least one of said first and second conductors comprises said lock or said key.

4. A security lock arrangement comprising a key operated mechanical lock and key in combination with an electronic security system comprising a transmitter for transmitting a coded electrical signal and a receiver for detecting the receipt of such signal or detecting , its absence, said mechanical lock and key being coupled by inhibiting means preventing or causing operation the means controlled -by the mechanical lock and key only when the receiver has detected the presence or absence of said signal, and wherein said transmitter is electrically connected to the key and the receiver is electrically connected to the lock so that said signal is transmitted by conduction through the key and lock.

5. A security lock according to Claim 3 or 4, wherein the person holding the key forms a means completing a signal path enabling detection of the signal by the receiver .

6. A security lock arrangement according to Claim 3, 4, or 5, wherein the transmitter is embodied in a cap fitted to the head of the key.

7. A security lock arrangement according to any of Claims 2 , 3 and 4, wherein the inhibiting means comprises an auxiliary lock separate from the mechanical lock and key.

8. A security lock arrangement according to Claim 7, wherein the auxiliary lock has a bolt operated by an electric motor under the control of the receiver.

9. A security lock arrangement according to Claim 3, 4, 5, or 6, wherein the lock is a tumbler lock and the means controlled thereby is a lock bolt or the like, said inhibiting means comprising a latch operated by a solenoid controlled in its turn by the receiver so that said lock bolt or the like is prevented from being operated until the receiver receives said signal from the transmitter.

10. A security lock arrangement according to Claim 9, wherein said latch is conditioned by the receiver to allow the lock bolt or the like to be operated as long as the key is in the lock and makes electrical contact therewith.

11. A security lock arrangement according to Claim 3, 4, 5, 6, 7, or 8 wherein the receiver has a memory which is programmed by the signal from the transmitter so that it will only operate the inhibiting means when it receives the signal to which it has been programmed , until the memory is wiped clear and the memory is reprogrammed.

12. A security lock arrangement according to Claim 11, wherein the receiver comprises a biassing electrical supply and disconnection of said supply wipes the memory clear.

13. A security lock according to Claim 11 or 12, wherein the transmitter can be programmed to vary the signal which is emitted thereby.

14. A security lock arrangement according to Claims 3, 4, 5, or 6 wherein said means controlled by the mechanical lock and key is a motor vehicle ignition circuit and said inhibiting means comprises the motor vehicle ignition coil or engine management system.

15. A security lock arrangement according to Claim.11, wherein the transmitter includes a battery for driving same and the receiver includes a memory and wherein disconnection of the battery from the receiver wipes the memory clean.

16. A security arrangement according to any of the preceding claims, wherein the receiver is programmed to recognise a coded signal in two portions A and B in that order, but if a key with a coded signal comprising two portions of which the first is B and the second is not A is presented to the receiver, it will operate the inhibitng means and will become reprogrammed to recognise that signal subsequently.