WO2000061897A1

WO2000061897A1 - Electronic lock mechanism

Info

Publication number: WO2000061897A1
Application number: PCT/DK2000/000171
Authority: WO
Inventors: Kristian Dogel STRØBECH
Original assignee: Stroebech Kristian Dogel
Priority date: 1999-04-12
Filing date: 2000-04-11
Publication date: 2000-10-19
Also published as: DK199900474A; AU3803000A

Abstract

Electronic lock mechanism designed with an electronic key which is not physically connected with the lock, and where the verification procedure for the electronic key is only initiated when the lock mechanism itself is physically activated or manipulated with an activity also having direct effect on the mechanical release of the lock itself. If the lock is made as a door lock, operation takes a very simple form. One takes hold of the door grip and moves it downwards as on a common door. If the correct electronic key is carried, the lock is released, and the door may be opened. If one does not carry the correct electronic key, the lock is not released and the door cannot be opened.

Description

ELECTRONIC LOCK MECHANISM

Background of the Invention

The invention concerns an electronic lock mechanism of the kind where verification occurs by electromagnetic signal transmission between the lock mechanism and an electronic key which is not necessarily connected physically with the lock, and where a physical activation or manipulation of the lock mechanism itself is used for mechanical release of the lock.

It is known to make electronic lock mechanisms that verifies authorisation for opening by electromagnetic signals.

A typical example is electronic locks for car doors where a receiver in the car is held in constant standby, and where a transmitter in a key is activated by the person desir- ing to open the car door when the person is so close to the vehicle that transmitter and receiver are within range of each other. The electromagnetic signals may be infrared light signals or radio signals.

An electronic lock of this type has the advantage that the person desiring to open such an electronic car lock may do this by an single action on key transmitter at a suitable distance from the car, without having to actuate the car lock physically with a key. Furthermore, an electronic key of this kind has the purpose that it may be connected with an alarm system and that a sound signal may indicate whether the car is in locked or open position, and whether the alarm system of the car is activated or deactivated.

An electronic lock of this type has, however, the disadvantage that the receiver in the car requires a constant power supply as to at any time being capable of picking up the signal from the key transmitter when the person desiring to unlock the car is activating it. It is also a drawback that the key is to be found and activated for initiating the veri- fication. The transmitting power usually has to have a certain level in order to ensure necessary range, and this opens the possibility of unauthorised persons tapping the verification code transmitted by the key. Another typical example of electronic locks are electronic locks for hotel rooms where the lock is activated by a reading mechanism on the door lock verifying, for example, a magnetic strip card or a punched card which is inserted into the reading mechanism of the lock by the person desiring the lock to the activated. An electronic lock of this type has the advantage that it may be re-coded an indefinitely number of times and thereby yields a greater degree of security against key copying and consequent unde- sired access for opening the lock than a common mechanical key. As compared with electronic lock systems, where verification codes are exchanged by wireless transmission, magnet strip and punched cards have the advantage that the code cannot be read at a distance.

An electronic lock of this type has, however, the disadvantage that the person desiring to activate the lock is to insert the magnet or punched card physically into the reading mechanism of the lock in order to achieve verification and access. The same electronic lock type has likewise the drawback that the magnet cards or punched cards to match may easily be copied for unauthorised use.

Also, there is known an electronic lock constantly transmitting verification signals in the form of electromagnetic waves, and where the key unit is a passive receiver, for example in the shape of an ID-card or a bracelet on which there is coded a verification code. Such an electronic lock has the advantage that the verification unit (key unit) is only to be located at a suitable distance from the lock in order that it will activate the lock mechanism without the person, who wants to open the lock, having to actuate this or the key unit physically.

Such an electronic lock has the disadvantage that it will always be activated when the key unit is within the range of the transmitted verification signals, whether or not the person carrying the key unit desires it. The lock type also has the drawback that it requires constant power supply in order always to be ready for activating the lock mechanism when the key unit is within range. The constant transmission of the verification inquiry also makes it easier for unauthorised persons to perform decoding since in principle there is unlimited time for analysis of the codes. There is also known an electronic lock which by means of electromagnetic waves transmits a verification signal when the person desiring the lock to be activated by pushing a button somewhere on the object to be locked causes the verification signal to be transmitted. The advantage of this electronic lock type is that the verification process is only initiated when the person performing the required verification manoeuvre desires. Furthermore, the power consumption may be reduced to the periods where a verification process is actually relevant.

Such an electronic lock has the drawback that there is added an electric contact, the only purpose of which is to provide the verification. When operating the lock, it first has to be released by activating the push-button, whereafter the door grip is to be operated. Furthermore, the lock mechanism itself may exclusively function with connected power supply, typically also including signal transmission from an externally disposed push-button.

From US 4,778,206 there is known an electronic locking mechanism of the kind mentioned in the introduction. In this lock mechanism there is performed a verification process by manipulating the door grip. This takes place by a separate movement and not in connection to the physical activation of the lock mechanism itself. Thus it will be possible to activate this mechanism. Thus it will be possible for an unauthorised person to tap the verification code from the lock mechanism.

From WO 99/28170 there is known another lock mechanism of corresponding type. Here it will also be possible for an unauthorised person to perform a part activation of a door grip whereby a verification process is initiated. A subsequent physical activation of the lock mechanism for the mechanical release will only be performed later. This lock mechanism is thus also connected with drawbacks.

From EP 0 927 803 Al there is known a further lock mechanism. However, this lock mechanism is based on using electric activation of the lock. Thus there is a need for energy supply so that the energy consumption for the activation of the lock may be considerable. The purpose of the present invention is to provide an electronic lock mechanism reducing the disadvantages connected with prior art electronic locks.

This is achieved with a lock mechanism of the kind mentioned in the introduction be- ing peculiar in that the electronic key is designed so that the verification procedure for the electronic key is initiated only when the lock mechanism itself is physically activated or manipulated by an activity which also has direct effect on the mechanical release of the lock itself.

When the lock mechanism, as a novelty, is designed so that the verification procedure is only initiated when the lock mechanism itself is physically activated or manipulated, a number of advantages are attained. Some of these may be achieved separately by prior art, but no lock types uniting all the advantages are known.

It is an essential advantage that the power consumption may be reduced to the periods where a verification process is actually relevant. There is no continual power consumption as is the case with most electronic lock types.

By connecting the verification process with the activation of the lock itself there is achieved the advantage that the time where the lock has a power consumption for mechanical active parts, e.g. electromagnets, is limited as much as possible. The duration of the power consumption may be reduced to few seconds or less by each activation.

By connecting the verification process to the activation of the lock itself there is fur- thermore achieved the very essential advantage that the forces to be exerted by mechanically active parts, e.g. electromagnets, do not have to be of such a magnitude that they can perform the work with releasing the lock itself. There is only required that they have sufficient strength for setting the lock in a mechanical state where the manual activation may release the lock.

Since there is a direct connection with the mechanical activation of the lock and the initiation of the verification process, the mechanical activation itself may be utilised as energy source by providing the power supply to the verification process and the possible release of the lock. This may e.g. be achieved by inserting a piezoelectric crystal in the mechanical connection in the lock which is manually activated. The piezoelectric crystal may be disposed so that it is subjected to pressure when the lock is activated mechanically by the user. The piezoelectric crystal thereby transforms some of the mechanical work performed on the crystal to electric energy which may be used e.g. for power supply for the transmitter/receiver unit and possibly also the electromagnet. Hereby the need for external voltage supply, e.g. in the form of dry cells, is completely or partly eliminated.

Since in dimensioning the transmitter/receiver system for the electronic verification it is presupposed that the electronic key is to be located on the person activating the lock, the transmitter/receiver system may be arranged so that it operates with low transmitting power. Thereby the power consumption is further reduced.

Furthermore, with low transmitting power there is achieved the advantage that the risk of unauthorised persons reading the codes exchanged at the verification is reduced as much as possible.

When the person activating the verification process has physical contact with the lock, there is achieved the advantage that the transmitting power may be further reduced several orders of magnitude. The lock may be designed so that the handle itself is the primary antenna for the transmitter. By having physical contact with the hand grip, the body of the activating person will act as an extra antenna, and by being in close con- tact with this, the electromechanical key is imparted a large signal strength. Hereby the risk of distant reading of codes is further reduced.

If the lock is designed as a door lock, operating it takes a very simple form. One gets hold of the door grip and moves it downward as by a common door. If one carries the correct electronic key, the lock is released, and the door may be opened. If one does not carry the correct electronic key, the lock is not released and the door cannot be opened. The means, whereby the advantages compared with prior art are achieved, appear from the patent claims.

Description of the Drawing The invention may then be explained further with reference to the accompanying drawing, where

Fig. 1 shows an electronic lock according to the invention in the shape of a door lock, and Fig. 2 shows a second electronic lock according to the invention in a version that may function as padlock, or, with lesser modifications, e.g. as bicycle lock.

The lock mechanism 1 in the present description is a latch bolt lock. The latch bolt 2 is guided by guides 3. It is normally kept in the locked position by the compression spring 4. The latch bolt has a riveted pull rod 5 which at the end opposite of the latch bolt has a bracket 6 with a bottom plate 7. The lock has a door handle not shown on the figure, but which engages the square hole 8 in the lever arm 9 which is suspended concentrically with the centre of the square hole 8. The lever arm and the door handle is normally held in neutral position by the tension spring 10. Close to its upper end, the lever arm has a pin 11 connecting the lever arm with the releasing pawl 12. At one end, the release pawl has a pin 13 biased by a tension spring 14 which is pre-tensioned by a pin 15 on the arm 16 controlled with a mechanical lock cylinder 17. At the other end, the release pawl 12 is passed through the bracket 6 where it is limited upward by the pull rod 5 and downward by the bottom plate 7. Outside the bracket, the release pawl has a pin 18 biased by a tension spring 19. Within the bracket, the release pawl has a carrier 20 having a small boss 21. The release pawl also has an armature for an electromagnet 22. The associated electromagnet 23 is disposed on a boss on the lever arm 9, and the same boss may activate a microswitch 24. The microswitch is connected electrically with the control unit 25 which also contains the transmitter/receiver part. The power supply is here with dry cells 26. To match with the lock there are a mechanical key and an electronic key with a transponder function which can return a reply code when it receives a signal of a certain strength from the transmitter/receiver part of the lock. The two key types may be united in one. The keys are not shown on the figure.

In its neutral position, the release pawl 12 is kept pressed up against the pull rod 5 since the tension spring 14 exerts a greater moment than the opposite tension spring 19. When the door grip is actuated as by a normal opening of the door, a turning movement of the lever arm 9 is initiated. Hereby the contact in the microswitch 24 is made. The transmitter/receiver part in the control unit 25 now receives voltage from the power supply 26 and transmits an inquiry for verification. If the electronic key reacts correctly with its transponder function and returns the correct answering code, the control unit 25 puts electric potential on the electromagnet 23. Hereby the armature plate 22 is attracted, and the release pawl 12 is pulled down against the bottom plate 7 in the bracket 6 as the sum of the moments from the electromagnet 23 and the tension spring 19 exceeds the moment from the tension spring 14. By the further turning movement of the door handle and the lever arm 9, the release pawl 12 is passed through the bracket 6, and since the release pawl is in lowered position, the carrier 20 will engage the bottom plate 7 of the bracket. The pin 21 ensures that the engagement is maintained when the voltage for the electromagnet is removed. With the further movement of the release pawl 12 which is now coupled with the bracket 6 by the engagement between the carrier 20 and the bottom plate 7, the latch bolt is withdrawn by the pull rod 5, and the lock is opened.

If the electronic key does not react correctly with its transponder function and omits to return the correct answering code, typically because the correct key is not within the range of the transmitter/receiver part, the control unit 25 does not provide electric potential on the electromagnet 23 when contact is made in the microswitch 24. Therefore, the armature plate 22 and the release pawl 12 are not attracted by the magnet. The release pawl therefore remains in its neutral position, held up against the pull rod

5 by the greater moment from the spring 14. When the release pawl 12 is passed through the bracket 6 by the further movement of the door handle and the lever arm 9 without the release pawl and thereby the carrier 20 being in lowered position, the carrier 20 does not engage the bottom plate 7 of the bracket, but may freely be slid further on without any effect on the bracket. The latch bolt is therefore not retracted by the pull rod 5, and the lock is not opened.

With the mechanical key, the lock cylinder 17 may be turned 90° so that the arm 16 will turn about upwards. Thereby the tension spring 14 is slackened so much that its moment on the release pawl 12 no longer exceeds the moment from the tension spring 19. The release pawl 12 is then pulled down into the position to which it will be drawn by the electromagnet 23, irrespectively of whether there is voltage on the magnet or not. The lock will then be opened by any activation of the door handle irrespectively of the electronic key being within range or not.

The lock 1 has a bracket 2 which in unlocked condition is kept extended by the lock with the compression spring 3. In locked condition, the pawl 4 blocks the bracket 2 in locked position. The pawl is held in engagement with the bracket by the compression spring 5. A bend of the pawl fitting down on an edge in the milled groove 6 ensures that positive locking always exist. The bracket 2 also has a sloping, milled groove. A wedge 8 may be pressed into the milled groove, and when its is pushed to the bottom, the bracket 2 is displaced deeper into the lock 1 so that the pawl 4 may clear the edge in the milled groove 6. The wedge 8 is pressed in with the push-button 10 which is suspended in a boss 9 on the lock 1. The force from the push-button is transmitted to the wedge through the piezoelectric crystal 11. The crystal and the push-button are normally kept out by the compression spring 12. The voltage generated by the piezoe- lectric crystal 11 is conducted to the control unit 14 which also contains the transmitter/receiver part, and which may retransmit voltage to the electromagnet 13.

An electronic key with transponder function belongs to the lock which may return an answering code when it receives a signal of a certain strength from the transmit- ter/recei ver part of the lock. In its locked position, the bracket 2 is held fast by the pawl 4. When the push-button 10 is actuated, the wedge 8 is pressed into the sloping milled groove 7, whereby the bracket 2 is slid more into the lock 1 , and the pawl 4 is released from the edge in the milled groove 6. By continued pressure on the push-button 10, an electric potential is generated in the piezoelectric crystal 11 for the transmitter/receiver part in the control unit 14. It transmits an inquiry for verification. If the electronic key reacts correctly with its transponder function and returns the correct answering code, the control unit 14 puts voltage on the electromagnet 13. Hereby the pawl 4 is attracted, and since the wedge 8 by its pressing into the sloping groove 7 has released the pawl from all fric- tional forces, the electromagnet only has to overcome the force in the spring 5. The pawl 4 is retracted, and when the push-button is released, the wedge 8 slides out of the sloping groove 7, and the bracket is free. The self-induction in the electromagnet 13, possibly supplemented by voltage from a condensator, makes the pawl 4 being retracted in open position for the period necessary for releasing the bracket 2.

If the electronic key does not react correctly with its transponder function and omits to return the correct answering code, typically because the correct key is not within range of the transmitter/receiver, the control unit 14 does not put voltage on the electromagnet 13 when the control unit receives electric potential from the piezoelectric crystal. Therefore, the pawl 4 is not attracted by the magnet, and the lock remains locked.

Claims

1. Electronic lock mechanism of the kind where verification occurs by electromagnetic signal transmission between the lock mechanism and an electronic key which is not necessarily connected physically with the lock, and where a physical activation or manipulation of the lock mechanism itself is used for mechanical release of the lock, characterised in that the electronic key is designed so that the verification procedure in relation to the electronic key is initiated only when the lock mechanism itself is physically activated or manipulated by an activity which also has direct effect on the mechanical releasing of the lock itself.

2. Electronic lock mechanism cf. claim 1, characterised in that the power consumption for the verification procedure is limited to the period in which the lock is physically activated or manipulated with the purpose of verification.

3. Electronic lock mechanism cf. one or more of preceding claims, characterised in that the physical activation or manipulation of the lock mechanism with the purpose of verification implies that the releasing parts in the lock are mechanically relieved so that the work to be performed by electromechanically active parts in the lock for opening the lock is considerably limited as compared with the total work in connection with opening the lock.

4. Electronic lock mechanism cf. one or more of preceding claims, characterised in that electromechanical active parts in the lock do not have such a strength that they can perform the work itself by opening the lock, but only have sufficient strength to put the lock into a mechanical state where the continued manual activation may open the lock.

5. Electronic lock mechanism cf. one or more of preceding claims, characterised in that the physical activation or manipulation of the lock mechanism with the purpose of verification is used wholly or partly as energy source for providing the electric power supply for the verification process and the possible release of the lock.

6. Electronic lock mechanism cf. claim 5, characterised in that the energy from the mechanical activation is converted into electric energy by piezoelectric means.

7. Electronic lock mechanism cf. one or more of preceding claims, characterised in that the transmission power in the verification transmitter of the lock has an effective range in relation to the electronic key limited to 1-5 m.

8. Electronic lock mechanism cf. one or more of preceding claims, characterised in that the object on the lock, which is physically activated or manipulated with the purpose of verification, is conductive and functions as antenna by the electromagnetic signal transmission.