Patent Publication Number: US-8540291-B2

Title: Device and method for unlocking a lock by use of monitoring of current

Description:
PRIORITY STATEMENT 
     This application is the national phase under 35 U.S.C. §371 of PCT International Application No. PCT/EP2008/052008 which has an International filing date of Feb. 19, 2008, which designated the United States of America and which claims priority on Swedish application No. 0700465-8 filed Feb. 23, 2007. 
     TECHNICAL FIELD 
     The present invention generally relates to access control, and more specifically to a method and a device for unlocking a lock. The present invention also relates to a method for mounting a lock to a door leaf. 
     BACKGROUND OF THE INVENTION 
     The most common way to lock and unlock an access-controlling object such as a door is probably by using a mechanical key. This solution is cost efficient and easy to use, and a mechanical lock is hard to force. The drawbacks are, however, that the user always has to bring the key and that a user having a key always can obtain access, since the key itself does not incorporate any restrictions. These and other problems have been addressed by the present applicant in the previous application WO-2006/098690, which describes a device and method for unlocking a lock by a lock device enabled for short-range wireless data communication in compliance with a communication standard. 
     The device and method described in WO-2006/098690 presents a solution to the above problems. The present invention mainly relates to improvements in the lock device and its actuation, while the method related to communication between the lock device and external units may be similar to what has already been described in said previous application. 
     Desired features for the lock device is operational safety and low power consumption, and it is beneficial if this can be achieved with a device having a limited physical size. Though the device presented in the previous application was, and still is, advantageous there are improvements to be made within the above desired features. 
     A common feature for lock devices of the above type is that there is generally no simple way of determining the position of the lock catch. The angular position of a lock knob on the inside of the door is usually not reliable, since a lock catch also can be actuated by using a key from the outside. If the lock catch is locked/released with a key from the outside, this will generally not affect the angular position of the lock knob. 
     The solutions provided for in prior art for detecting the position of the lock catch in order to determine when the door is locked/unlocked, generally includes the provision of specific sensors in the actual lock mechanism or on another structural component of a lock, which makes these alternatives more costly and complex, both in terms of components needed and in terms of installation efforts. They are also disadvantageous in terms of power consumption. 
     The inventive concept can be used on any existing lock having rotatable lock actuating means on the inside, and can with ease be installed on most commercial locks using a lock knob. The inventive concept is also applicable when producing locks, and can as such be incorporated into lock cases during production thereof. 
     SUMMARY OF THE INVENTION 
     The inventive device and method as disclosed in claims  1  and  10 , respectively alleviates several problems found in prior art devices. 
     A lock device applying the inventive concept is adapted to unlock a lock by transferring a lock catch from a locking position to a releasing position. The device has an electric motor mechanically connected to an axle by means of at least one transmission means, and wherein rotation of said axle actuates said lock catch, and is characterized in that it comprises means for monitoring the current consumed by the electric motor. 
     The use of said monitor means makes it possible to determine a position of the lock catch without any other physical sensor means, such as magnets/hall elements which have been used in prior art. 
     The device may further comprise means for evaluation of the monitored current and storage means for storing current characteristics, such as a preset value, like a threshold value or a reference curve, regarding the current. The storage means makes it possible to store several reference current characteristics. By doing this it is possible for the device to automatically determine what type of lock it has been installed to, features of that particular lock, such as temporal distance between an locked and unlocked position, current appearance when a final stop is reached etc. The motor is then capable of operating in accordance with that particular type of lock. If, e.g., the lock is spring biased the device will deduce that the motor will need to apply torque until the door is opened, since if its not, the lock catch will return to a locked state. Other advantages will be apparent from the detailed description which will follow. 
     Further, the device may be capable of determining whether the lock device is in a locked/unlocked state or not based on a comparison between the monitored current and the stored current characteristics. These and more advantages are disclosed in the detailed description. 
     The transmission means may further comprise a weakening structure adapted to break and disrupt the mechanical connection between the electric motor and the axle if a predetermined threshold force is exceeded. In the event of the motor seizing there might occur a situation where the lock is impossible to unlock. Then the above solution makes it possible to dimension the weakening structure such that it can withstand the force needed to operate the lock, while it still is possible to apply a force large enough to break the weakening structure simply by using manual force, turning the knob or similar. The lock could seize in other ways and instead of breaking expensive and/or complex components in the lock the only thing that will break when the lock is forced opened is the weakening structure. This is a cost efficient solution and it also reduces the service costs. 
     The transmission means may comprise a gear wheel having a central region, a peripheral region, and an intermediate weakening region, wherein the weakening structure is arranged in the weakening region. The transmission means transfers the torque from the motor to the axle, and it is natural that it includes a gear wheel. The gear wheel is easily provided with a weakening region and it is generally a component which is inexpensive to keep in stock and simple to replace. 
     The weakening structure may comprise a structural weakening, such as apertures, recesses or cavities in the weakening region. This is an efficient way of obtaining a weakening region, e.g. by drilling or machining apertures leaving a well defined amount of material left. 
     The weakening structure may also/instead comprise an adhesive bond, releaseably bonding the central region to the peripheral region. 
     The weakening structure comprises at least one structure extending radially between the central region and the peripheral region. 
     A method for locking/unlocking a lock with a lock device having a motor controller controlling an electrical motor mechanically connected to a lock catch of the lock and means capable of monitoring the current consumed by the motor, comprises the steps of
         sending instructions to a motor controller to actuate the motor in an opening direction,   monitoring the current consumed during the operation of the motor,   comparing the current consumed as a function of time with reference current characteristics,   determining when the lock is locked/unlocked based on said comparison,   stopping actuation of the motor.       

     The method may utilize a lock according to the description contained herein. 
     There are several ways for the skilled person to realize the invention, but in a preferred embodiment the monitor means are localized on a circuit board and the signal from the monitor means are forwarded to a memory via an amplifier, a filtering unit, A/D converter and a processor. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above, as well as additional objectives, features and advantages of the present invention, will be better understood through the following illustrative and non-limiting detailed description of preferred embodiments of the present invention, where the same reference numerals will be used for similar elements. 
         FIG. 1   a  is a perspective sectional view of a lock device using the inventive concept. 
         FIG. 1   b  is a another lock device using the inventive concept mounted to a door leaf. 
         FIG. 2   a  is a detailed perspective view of a second gear wheel of the lock device. 
         FIG. 2   b  is a detailed plan view of an alternative design of the second gear wheel. 
         FIGS. 2   c  and  2   d  show additional components which can be used in connection with the second gear wheel of  FIG. 2   b    
         FIG. 3  is a side view of the gear wheel of  FIG. 2   a.    
         FIG. 4  is a diagram showing a current consumption as a function of time for a lock device, which illustrates the basis for the invention according to one embodiment of the invention. 
         FIG. 5  is a schematic illustration of a telecommunication system, including a wireless key device implemented by a mobile terminal, a wireless lock device for a door, a wireless administrator device implemented by a mobile terminal, an administrator server, a mobile telecommunications network and a couple of other elements, as an example of an environment in which the present invention may be applied. 
         FIG. 6  is a schematic front view illustrating the wireless key device of  FIG. 5 , and in particular some external components that are part of a user interface towards a user of the wireless key device. 
         FIG. 7  is a schematic block diagram illustrating internal components and modules of the wireless lock device of  FIG. 1 . 
         FIGS. 8 and 9  are flowchart diagrams of a method of unlocking the lock device by the key device of the previous drawings. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Referring now to  FIGS. 1-4 , a lock device  140  according to a first embodiment of the invention will be described in more detail. In  FIG. 1 , the door  150  is shown in more detail. In a well-known manner the door has a lock  140  which includes an internal lock mechanism confined in a lock case (not shown in  FIG. 1 ) as well as a door handle  161 , a lock knob  162  and a lock catch  163 . The lock knob  162  is mounted fixedly at one end of a rotatable axle  164 . The lock device  140  is mounted to a base plate  154  which is attached to the door leaf  152  next to the lock  160 . A user may manually unlock the door lock  160 , from the inside of the premises which are protected by the door  150 , by turning the lock knob  162 . This will cause rotation of the axle  164  and, ultimately, retraction of the lock catch  163  from its extended locking position in  FIG. 1  to a retracted releasing position. 
     Other components of the lock device  140  are mounted to the base plate  154 . In the illustrated embodiment an iron less electric DC motor  308  is attached to the base plate  154 . A transmission axle  308   a  of the motor  308  is provided with a first gear wheel  308   b  as transmission means. The gear wheel  308   b  has a frustoconical shape with axially extending teeth along its periphery and engages a second, larger gear wheel  166 , the gear ratio being approximately 5:1. The gear ratio in the planetary gear (not shown) of the DC motor is approximately 24:1, resulting in an overall gear ratio of about 100:1. The larger gear wheel  166  is circular with a rotational axis coinciding with the rotatable axle  164  onto which the larger wheel  166  is mounted. 
     A motor controller  307  ( FIG. 7 ) is coupled to the motor  308  and is adapted to provide a control signal  307   b  for engaging or disengaging the motor  308  and the carrier means. In turn, the motor controller  307  is controlled by a control signal  307   a  from a CPU  313  in the lock device  140 . 
     Actuation of the motor  308 , via the motor controller  307  thus rotates the transmission axle  308   a , which in turn rotates the smaller gear wheel  308   b  causing it to rotate the larger gear wheel  166 . Rotation of the larger gear wheel  166  cause rotation of the rotatable axle  164 , which actuates the lock catch. 
     The device comprises means for monitoring the current consumed by the DC motor over time. The sensor means include suitable components arranged on a circuit board. The current consumed by the motor is proportional to the torque its transmission axle  308   a  needs to overcome. Disregarding the frictional losses related to the gear wheels, this torque and thus the current, will be proportional to the force needed to move the lock catch. 
     In order to elucidate the function of the monitoring means, consider a case where initially the lock catch is in a locking position. From this position the DC mofor can try to turn the rotatable axle  164  in a locking direction or an opening direction. 
     If the rotatable axle  164  is turned in a locking direction it will typically rotate with relative ease during a part of a revolution after which it reaches a permanent stop. In this case the monitor means will detect a low, essentially constant current consumption followed by a rapid increase in consumption, as shown in  FIG. 4 . 
     On the other hand, if the rotatable axle is turned in an opening direction it will typically rotate with relative ease until it starts engaging the lock catch. At that point there will be an increase in the force needed for rotation of the axle, and thus in the consumption of current. Once the lock catch reaches a releasing position the rotatable axle will again rotate with relative ease until it also in this case reaches a permanent stop. In this case the monitor means will detect a low, essentially constant current consumption followed by an increased, but still moderate temporary increase in consumption, followed by a low, essentially constant consumption followed by a rapid increase in consumption. 
     It should be understood that if the lock catch is in a releasing position the current consumption properties will be essentially reversed. In this context it should also be mentioned that there are lock mechanisms for which the lock catch is locked or released in two consecutive steps, which will have an obvious impact on the appearance of the current consumption curve. 
     In practise a reference current is recorded once the lock device is installed. As a first step in a referencing procedure the lock catch is first manually positioned in maximum locked position. The second step is to initiate the automatic part of the procedure. The motor is then instructed to rotate in one direction and when it has reached the end of that rotation it reverses and rotates in the other direction until it again reaches a permanent stop. 
       FIG. 4  shows an example of a recorded reference current as a function of time. The diagram showed in  FIG. 4  illustrates a situation where the rotatable axle  166  has been turned in an opening direction. It is evident from the curve (full line) that there is a start current followed by the above mentioned low, essentially constant current consumption. Thereafter the lock catch is operated, indicated by the well defined increase and decrease in current consumption, again followed by a constant region. At the end the lock catch reaches its permanent stop position, which results in a rapid increase in current consumption. After current components like start current and such have been removed, a corrected current curve can be obtained, the dotted line of  FIG. 4 . 
     The inventive use of the monitoring of the current opens up for several evaluation parameters. First, after the referencing procedure is finalized the lock device has recorded the reference current and deduced the answer to a number of questions from this, e.g.:
         i) Which one is the closing direction? This makes it possible to install the lock device to any type of door (opening left or right) without tailor-made configurations.   ii) What are the characteristics when the lock device reaches a permanent stop?   iii) What are the characteristics when the lock catch is actuated?   iv) What are the characteristic time periods between events, e.g., from lock actuation to permanent stop?       

     The answers to the above questions provide detailed information which may be used during actual locking and unlocking of the lock using the lock device. Further evaluation parameters include:
         v) Estimation of power consumption, estimation of life time       

     For the type of lock device described the power consumption is a feature which is particularly interesting to monitor. For the device, small batteries providing large currents, such as lithium-thionyl chloride batteries, are preferably used. The characteristics of this type of battery is not unambiguously connected to the power left in the battery. Therefore it is advantageous to measure and store the power consumption and from that estimate the remaining life time of the battery, since the internal resistance is increased and therefore the maximum output current is lower when little capacity is left in the battery.
         vi) Measurement of peak current, compare later during operation or additional referencing procedure,       

     The peak current may then be compared with the peak current during a later referencing procedure, or during the actual use of the lock device. This measurement too can be used for estimation of the power left in the battery. 
     Generally, measured changes in the evaluation parameters can be attributed to changes in the components of the device. This includes properties of the battery as discussed above, but also the status for the mechanical components. As the mechanical components of the lock device or the lock get worn, this will affect the internal friction and thus the appearance of the monitored current. The evaluation parameters can thus be used to trigger an overhaul of the lock device, in which gear wheels and/or other components are exchanged. 
     In a simple embodiment only the characteristics concerning the permanent stops are used. It is evident from the diagram of  FIG. 4  that a threshold value can be set for this purpose. Once the threshold value has been reached it can be determined that an end position has been reached, and the motor can be stopped in order to save power. 
     If a person activates the lock device from the outside, e.g., by knocking on the door, the lock device will first confirm that the individual knocking on the door is permitted to enter. Then the motor will rotate in an opening direction, and stop rotating once the threshold value is reached, irrespective of if the lock catch was locked or released to begin with. The individual can then enter. 
     If a person activates the lock device from inside, e.g., by pressing a button initiating a locking procedure, the lock device will first confirm that there are means, such as a portable phone with access rights, in the vicinity (to prevent the individual from locking him- or herself out), after which it will rotate the motor in a closing direction until the current consumption reaches the threshold value. 
     If desired it is always possible to use the lock knob to lock/unlock the door from the inside as well as a key to lock/unlock the door from the outside. 
     In more elaborate embodiments the summation current consumed during the actuation of the lock catch can be used. In other embodiments the inclination of the curve can be used instead of the threshold value. Both these actions make it possible to stop the motor even earlier and thus reduce the power consumption further. The power consumption is an issue since the lock device preferably is battery operated in order to simplify the installation procedure. Mechanical wear caused by strain of the components is also an issue, and this is also reduced by using the above method. 
     During mounting of the lock device the lock knob  162  is temporarily removed from the lock  140  and the base plate  154  is mounted to the door leaf  152 . The base plate  154  can obviously be mounted by using any suitable means, but generally it is mounted using pre-existing fastening screws which are used to fasten a protective plate that for most locks is situated between the lock knob and the door leaf. The idea is to cause no or minimal damage to the door blade  152 . The reason for this is both related to improving the aesthetical appearance as well as not to compromise safety. With, e.g., metal doors the use of pre-existing fastening means, such as screws, also simplifies the actual mounting. In the illustrated embodiment the protective plate (not shown) has been replaced by a circular fastening plate (not shown) and the base plate  154  is subsequently fastened to the fastening plate. This arrangement simplifies the possibility of mounting the base plate  154  in different directions, since it can be arranged in any angle around the periphery of the fastening plate. 
     For illustrative purposes the circuit board, comprising, e.g., a motor controller and communication means, is not shown in  FIG. 1 . The battery pack  308   c , normally arranged on the portion of the base plate remote to the rotatable axle, is shown  FIG. 1   b.    
     The base plate also comprises attachment points for a protective cover (not shown). The lock knob  162  is arranged on the rotatable axle  164  after said protective cover has been mounted. 
     A user wanting to lock or unlock the door from the inside simply turns the knob  162  and thus actuates the lock catch and unlocks the door. This will also turn the larger gear wheel  166  and consequently rotate the transmission axle  308   a  of the DC motor  308 . Since the described type of motor does not cause any significant mechanical resistance making the lock knob  162  difficult to turn, not even with the disclosed gear ratio, there is no need to include a disengagement system. Nevertheless a reason for adding a disengagement system could be to reduce the wear on components. Another reason could be that the mechanical friction in the lock, which is experienced when locking/unlocking manually using the knob  162 , may remain unchanged, the lock will thus “feel” the same as before installation of the inventive system. The device of  FIG. 1   b  actually includes a disengagement system which will be explained in more detail referring to  FIGS. 2   b ,  2   c  and  2   d . The disengagement system basically operates as follows: A hub  180 , having a lug  182  (see  FIG. 2   c ) is concentrically arranged in engaging contact with the axle  164 . When the axle  164  is turned, as a consequence of a user turning the knob  162 , so is the hub  180 . A ring  186  having an arm  188  (see  FIG. 2   d ), is arranged coaxially with the hub  180  such that after the hub  180  has completed almost one revolution the lug  128  will engage the arm  188 . The ring  186  will then rotate with the hub  180 . After completion of a second revolution the arm  188  will engage a second lug  178  on the second gear wheel  166 , and now at first the transmission will be engaged, via the second gear wheel  166 . A user will consequently be able to turn the knob  162  almost two full revolutions before experiencing any additional resistance from the transmission means. 
     A user wanting to lock or unlock the door from the outside can either use a key or instruct the motor controller  307  to control the motor by any means described above or below. 
       FIG. 2   a, b  are detailed perspective views of a front side of a larger gear wheel  166  according to a second inventive concept, which may be used without the currentmonitor function. The gear wheel is essentially circular and comprises three functional regions.
         A central region having, at its rotational centre, an axial through hole  168  having a shape that enables it to matingly cooperate with the rotatable axle  164 . The central region comprises a circular projection  170 , see  FIG. 6 , that fits in a hole in the base plate  154 . Said circular projection  170  also comprises, around its outer periphery, a groove  172  in which it is possible to arrange a locking ring (not shown) once the projection  170  is inserted through the base plate  154 .   A peripheral region on which the gear teeth  174  of the second gear wheel  166  are arranged. The teeth  174  extends radially on the upper side of the gear wheel  162 . The toothed portion is slanted outwardly in order to correspond to the frustoconical shape of the smaller gear wheel  308   b.      The central region and the peripheral region are coupled by a weakening region. The weakening region is essentially a small number (three in  FIG. 2 ) of structures  176  extending radially between the central region and the peripheral region. The number and/or the dimensions, of the weakening structures  176  can and should be varied depending on the structural material as well as the predetermined force needed to break them. Generally the weakening structures  176  should withstand the forces expected during normal operation of the lock, i.e. the torque that can be delivered by the motor (with the gear ratio in mind). It should be noted that the weakening region also could be considered to be composed of the apertures/recesses/cavities being formed between the structures  176 .       

     Note that the weakening structures described are examples only. Other examples include the use of glue, adhesive, etc between the central region and the peripheral region, or any other coupling having the desired properties. 
     Note that the position of the weakening region, between the central region and peripheral region, results in that it is not subjected to any significant force in a situation where the lock catch is actuated by means of the lock knob  162  from the inside or a physical key from the outside. The only force that they are subjected to in that situation is the force needed for rotation of the inactive DC motor. 
     The weakening region is useful if some part of the transmission, or even the DC motor, seize or get stuck in any other way. In such a situation it might be impossible to operate the lock device but with the lock knob, or with a key from the outside. Since the lock knob  162  is mechanically coupled to the motor, via the transmission means, the lock knob  162  too will be stuck. However, thanks to the weakening structures  176  of the weakening region it is still possible to turn the lock knob  162  and unlock the door. The weakening structures  176  will break when a predetermined threshold force is applied. The lower limit for this force was discussed above and the upper limit is that it should be easy to overcome manually by use of the lever action of the lock knob  162 . 
     The broken larger gear wheel  166  is easily replaced at a low cost. In the illustrated embodiment the first gear wheel  308   b  is removed from the transmission axle  308   a , and after the locking ring is removed from the groove  172  in the larger gear wheel  166  the latter can be removed and replaced. The fact that the weakening structures will break first reduces the risk of other components getting damaged during the forced opening of the lock. 
     Both the small and the large gear wheel can be made of polymer such as PTFE, polyamide, metal or any other suitable material. 
     The present invention may advantageously be used in connection with the method and device disclosed in the above-mentioned WO 2006/098690. This document describes a communication function that may preferably be realized in a method for unlocking a lock by a lock device enabled for short-range wireless data communication in compliance with a communication standard, the method comprising the steps of: 
     a) detecting a key device within operative range of the lock device; 
     b) determining a wireless communication address of the key device; 
     c) evaluating the determined key device address by reference to a data storage with a number of wireless communication addresses stored therein; 
     d) generating an evaluation result from said evaluating step c), wherein a match between the determined key device address and any of the wireless communication addresses stored in the data storage is a requisite for a positive evaluation resuit; and 
     e) unlocking said lock if a positive evaluation result is generated in step d). 
     Steps a) and b) of detecting and determining are performed without establishment of any two-way communication link between lock device and key device pursuant to said communication standard, and therefore the unlocking method according to a first aspect is much faster than the unlocking method previously known. Moreover, it will allow also less advanced wireless communication devices to act as key devices. 
     The communication standard is preferably BlueTooth™, and steps a) and b) may thus involve: 
     paging for BlueTooth™ enabled devices within operative range by sending inquiry requests; 
     receiving an inquiry response from said key device; and 
     obtaining said wireless communication address of said key device by reading its BlueTooth™ address from said inquiry response. 
     Step b) may further involve determining a current time; and steps c) and d) may further involve comparing said current time with a number of time slots associated with a particular one of the stored wireless communication addresses that matches the determined key device address, a requisite for a positive evaluation result being that the current time falls within any of said time slots. 
     The wireless communication addresses stored in the data storage may be associated with respective authority levels, wherein steps c) and d) may involve: 
     for a particular one of the stored wireless communication addresses that matches the determined key device address, generating a first evaluation result if an authority level associated with said particular address meets or exceeds a predetermined authority level, and otherwise generating a second evaluation result, 
     wherein said first evaluation result corresponds to said positive evaluation resuit and causes performance of step e), and 
     wherein said second evaluation result causes, instead of step e), performance of the following steps: 
     f) establishing a two-way communication link between said lock device and said key device pursuant to said communication standard; 
     g) receiving verification data from said key device over said communication link; 
     h) authenticating said key device by matching the received verification data with authentication data stored in said data storage and associated with said particular address; and 
     i) upon successful authentication of said key device in step h), unlocking said lock. 
     This allows handling of certain prioritized and/or trusted users according to the fast unlocking method described earlier, whereas other users may be checked more carefully by retrieving their verification data over the two-way communication link for examination in the lock device. 
     Time slots are preferably provided in first and second types, said first type of time slot representing a first authority level which meets or exceeds said predetermined authority level, and said second type of time slot representing a second authority level which is below said predetermined authority level, the method involving the step of deciding that said authority level associated with said particular address is said first authority level if said current time falls within at least one time slot which is of said first type and is associated with said particular address. 
     The verification data may include a PIN (Personal Identification Number) code, or biometric data in the form of e.g. a digital fingerprint sample. 
     The method may further involve the introductory steps of detecting the presence of a user in a vicinity of said lock device and in response triggering performance of step a). This allows the lock device to rest in a sleep mode with negligible power consumption during periods of inactivity. Only elements that handle the detection of the user&#39;s presence will need to be active during such a sleep mode. In turn, such optimum power preservation allows implementing the lock device as a stand-alone device that may operate autonomously for long periods of time, powered by its own power source such as batteries. 
     The presence of the user may be detected by receiving a detection signal from a proximity sensor positioned and adapted to monitor the vicinity of said lock device. The proximity sensor may be selected from the group consisting of: an IR (Infra-Red) sensor, an ultra-sound sensor, an optical sensor, an RF (Radio Frequency) sensor or a pressure sensor. Alternatively, for embodiments where the lock device is mounted to a door having a door handle, the proximity sensor may be positioned on or at said door handle and be adapted to generate said detection signal by electrically detecting interaction from said user on said door handle. 
     A step of storing said wireless communication address, as determined in step b), in said data storage allows generation of a log file and/or statistics by collecting wireless communication addresses for different key devices as stored in the data storage; and transmission of said log file and/or statistics to said key device over said communication link. 
     The method may involve the steps of 
     receiving authentication data updating information from said key device over the communication link established in step f); 
     determining a first time stamp in the authentication data updating information received, said first time stamp reflecting a time of origin for the authentication data updating information; 
     determining a second time stamp for the authentication data currently stored in the data storage in the lock device; and 
     updating the authentication data currently stored in the data storage in the lock device with authentication data included in the authentication data updating information received, if said first time stamp is newer than said second time stamp. 
     Further steps may involve 
     determining a third time stamp in the authentication data updating information received, wherein said third time stamp reflects a time of receipt of said authentication data updating information at said key device from a remote server, and wherein said first time stamp reflects a creation time of said authentication data updating information at said server; and 
     performing said updating step only if said first time stamp is older than said third time stamp, and both of said first and third time stamps are newer than said second time stamp. 
     In general terms the inventive device is a lock device for unlocking a lock, having 
     means for short-range wireless data communication device in compliance with a communication standard; 
     means for detecting a key device within operative range of the lock device; 
     means for determining a wireless communication address of the key device; 
     a data storage with a number of wireless communication addresses stored therein; 
     means for evaluating the determined key device address by referring to the number of wireless communication addresses stored in the data storage and generating an evaluation result, wherein a match between the determined key device address and any of the wireless communication addresses stored in the data storage is a requisite for a positive evaluation result; and 
     means for unlocking said lock if a positive evaluation result is generated. 
     Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to “a/an/the [element, device, component, means, step, etc]” are to be interpreted openly as referring to at least one instance of said element, device, component, means, step, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated. 
     The present invention is advantageously implemented in a mobile telecommunications system, one example of which is illustrated in  FIG. 5 . Central elements in  FIG. 5  are a wireless key device (KD)  100  and a wireless lock device (LD)  140 . The purpose of the lock device  140  is to control some sort of lock mechanism in a lock, which in the illustrated example is a door lock on a door  150 . In turn, the lock device  140  is operated by the key device when brought in the vicinity of the lock device. In more particular, both the key device  100  and the lock device  140  are enabled for short-range wireless data communication in compliance with a communication standard. In the preferred embodiment, this communication standard is Bluetooth™. Having been the de facto standard for short-range wireless data communication for mobile devices during several years already, Bluetooth™ is believed to be very well known to the skilled person, and no particulars about Bluetooth™ as such are consequently given herein. 
     As with most other contemporary mobile telecommunications systems, the system of  FIG. 5  provides various telecommunications services such as voice calls, data calls, facsimile transmissions, music transmissions, still image transmissions, video transmissions, electronic message transmissions and electronic commerce for mobile terminals in the system, such as aforementioned mobile terminal  100 , another mobile terminal  106 , personal digital assistants (PDA) or portable computers. It is to be noticed that these various telecommunications services are not imperative to the invention, and for different embodiments, different ones of the telecommunications services may or may not be available. 
     In  FIG. 5 , the key device  100  is implemented by any commercially available, Bluetooth&#39;-enabled mobile terminal  100 , one embodiment  200  of which is shown in  FIG. 2 . As seen in  FIG. 2 , and as is well known in the art, the mobile terminal  200  comprises an apparatus housing  201 , a loudspeaker  202 , a display  203 , an input device  204   a - c , and a microphone  205 . In the disclosed embodiment, the input device  204   a - c  includes a set of keys  204   a  arranged in a keypad of common ITU-T type (alpha-numerical keypad), a pair of soft keys or function keys  204   b , and a biometrical data reader  204   c  in the form of a fingerprint sensor. Hence, a graphical user interface  206  is provided, which may be used by a user of the mobile terminal  200  to control the terminal&#39;s functionality and get access to any of the telecommunications services referred to above, or to any other software application executing in the mobile terminal. With particular reference to one embodiment of the present invention, the keypad  204   a  may be used for entering a PIN code to be used for authenticating the key device  100  in the lock device  140  in order to decide whether or not to unlock the lock controlled by the lock device. In another embodiment, the biometrical data reader  204   c  is used correspondingly to produce a digital fingerprint sample from the user, said fingerprint sample being used for authenticating the key device  100  in the lock device  140  by matching with prestored fingerprint templates. 
     In addition, but not shown in  FIG. 6 , the mobile terminal  200  of course comprises various internal hardware and software components, such as a main controller (implemented e.g. by any commercially available Central Processing Unit (CPU), Digital Signal Processor (DSP) or any other electronic programmable logic device); associated memory, such as RAM memory, ROM memory, EEPROM memory, flash memory, hard disk, or any combination thereof; various software stored in the memory, such as a real-time operating system, a man-machine or user interface, device drivers, and one or more various software applications, such as a telephone call application, a contacts application, a messaging application, a calendar application, a control panel application, a camera application, a mediaplayer, a video game, a notepad application, etc; various I/O devices other than the ones shown in  FIG. 6 , such as a vibrator, a ringtone generator, an LED indicator, volume controls, etc; an RF interface including an internal or external antenna as well as appropriate radio circuitry for establishing and maintaining an RF link to a base station; aforementioned Bluetooth™ interface including a Bluetooth™ transceiver; other wireless interfaces such as WLAN, HomeRF or IrDA; and a SIM card with an associated reader. 
     The mobile terminals  100 ,  106  are connected to a mobile telecommunications network  110  through RF links  103 ,  108  via base stations  104 ,  109 . The mobile telecommunications network  110  may be in compliance with any commercially available mobile telecommunications standard, such as GSM, UMTS, D-AMPS or CDMA2000. 
     The mobile telecommunications network  110  is operatively connected to a wide area network  120 , which may be Internet or a part thereof. Various client computers and server computers, including a system server  122 , may be connected to the wide area network  120 . 
     A public switched telephone network (PSTN)  130  is connected to the mobile telecommunications network  110  in a familiar manner. Various telephone terminals, including a stationary telephone  132 , may be connected to the PSTN  130 . 
     The CPU  313  is programmed to read and execute program instructions stored in a memory  311  so as to perform a method for wireless automatic unlocking of the lock  160  in response to the appearance and proper authentication of the key device  100 . An embodiment of this method is illustrated in  FIGS. 8 and 9  and will be described in more detail later. 
     The lock device  140  is a stand-alone, autonomously operating device which requires no wire-based installations, neither for communication nor for power supply. Instead, the lock device  140  is powered solely by a local battery power unit  303  and interacts with the key device, as already mentioned, by Bluetooth™-based activities. To this end, the lock device  140  has a Bluetooth™ radio module  309  with an antenna  310 . 
     The lock device  140  of the present embodiment further includes a real-time clock  304  capable of providing the CPU  313  which an accurate value of the current time. A detector  312   b  is positioned to detect that the door  150  is in a properly closed position, so that the CPU  313  may command locking of the lock  160  a certain time after a user has opened the door through the key device  100  and passed therethrough. The detector  312   b  may be a conventional magnetic switch having a small magnet mounted to the door frame and a magnetic sensor mounted at a corresponding position on the door leaf  152 . 
     The lock device  140  may have a simple user interface involving button(s)  305 , a buzzer  312   a  and LED indicator(s)  312   c . In some embodiments, an authorized administrator (ADM) may configure the lock device  140  through this user interface. In other embodiments, though, configuration of the lock device  140 —including updating the contents of a local database (LD-DB)  142  stored in memory  311  and containing i.a. key device authentication data—occurs wirelessly either directly from a proximate mobile terminal  106  over a Bluetooth™ link  116 , or by supplying a key device, for instance key device  100 , with authentication data updating information from a system database  124  at the system server  122  over the mobile telecommunications network  110 . 
     Since the lock device  140  is a stand-alone, battery-powered installation which is intended to be operative for long time periods without maintenance, it is important to keep power consumption at a minimum. Therefore, the present embodiment is designed to put itself in a sleep mode after a certain period of inactivity. In the sleep mode, the elements of the lock device  140  are inactive and consume negligible power. The way to exit the sleep mode and enter operational mode is by applying a wake-up control, signal  326  on a particular control input on the CPU  313 . To this end, the lock device  140  is provided with a wake-up arrangement  320  having a proximity sensor  324  and associated circuitry  322 . 
     The proximity sensor  324  is positioned to detect the presence of a user in a vicinity of the lock device  140 , and in response the circuitry  322  is adapted to generate the wake-up control signal  326 . The proximity sensor  324  may for instance be an IR (Infra-Red) sensor, an ultra-sound sensor, an optical sensor, an RF (Radio Frequency) sensor or a pressure sensor. Such types of sensors are all well known to the skilled person and are commercially available. For instance, when the proximity sensor  324  is an RF sensor, it may advantageously be adapted to detect mobile telecommunications traffic, such as GSM traffic, to or from the mobile terminal which implements the key device  100 . Thus, in this case the proximity sensor  324  does not detect the user himself but the key device  100  he carries. When the proximity sensor  324  is a pressure sensor, it may advantageously be located at floor level somewhere near the door  150 , so as to detect pressure variations caused be the user when stepping on the floor. 
     Alternatively, the proximity sensor  324  may be positioned on or at the door handle  161  and be adapted to generate a detection signal by electrically detecting interaction from the user on the door handle, for instance by capacitive means or by detecting the closure of an electric circuit. 
     Additionally, means such as a depressible button may be provided on or at the door  150  on the inside of the premises in question. The user may avail himself of such means to cause forced unlocking of the door lock  160  when he desires to leave the premises. To this end, such means will be coupled to the CPU  313 , and the latter will be adapted to perform the forced unlocking of the door lock  160  by generating the control signal  307   b  to the motor controller  307  so as to control the motor  308  in the manner previously described. 
     Referring now to  FIGS. 8 and 9 , an operational method performed by the lock device  140  for wireless automatic unlocking of the lock  160  will now be described in detail. 
     On a general level, the method consists of two main authentication stages  620  and  640 , and, in the present embodiment but optionally, an initial wake-up stage  610 . The first authentication stage  620  is designed to be fast and therefore does not involve any establishment of a two-way Bluetooth™ communication link between lock device and key device. Experiments have indicated that the first authentication stage, resulting in the opening of a door, may be completed in as little time as 2-4 seconds, which is considerably faster than in the prior art. 
     In the first authentication stage, authorization is based solely on the key device&#39;s Bluetooth™ address and the current time, both of which are detected automatically by the lock device  140  and require no interaction from the user (other than bringing the key device  100  near the door  150 ). Certain prioritized users are entrusted to unlock the door  150  simply through this first authentication stage  620 , whereas other users must be authorized during the following, second and more extensive authentication stage  640  which requires establishment of a two-way Bluetooth™ communication link and involves additional verification data from the key device  100 —in the form of a PIN code in the present embodiment. 
     The lock device  140  bases its operation upon the authentication data stored in LD-DB  142 . In the present embodiment, the record structure of the LD-DB  142  includes the following data fields for authentication data: 
     
       
         
           
               
               
               
             
               
                   
               
               
                   
                 Contents  
                 Contents  
               
               
                 Field 
                 example #1 
                 example #2 
               
               
                   
               
             
            
               
                 LD ID 
                 121 
                 121 
               
               
                 User name 
                 Olle 
                 Johan 
               
               
                 Bluetooth ™ ID 
                 0x00223af3 
                 0x002e5af4 
               
               
                 Stage-1 time slot (1) 
                 2005-03-24: 19-22 
                   
               
               
                 Stage-1 time slot (2) 
                 Mon-Fri: 07-15 
                   
               
               
                 . . . 
                   
                   
               
               
                 Stage-1 time slot (n) 
                   
                   
               
               
                 Stage-2 time slot - single 
                   
                   
               
               
                 Stage-2 time slot - scheduled 
                 00-24 
                 Sat-Sun: 10-18 
               
               
                 PIN code 
                 **** 
                 **** 
               
               
                 Administrator 
                 No 
                 No 
               
               
                   
               
            
           
         
       
     
     In the example given above, it is thus configured that user Olle is authorized to open the door  150 , through the lock device  140  having ID  121 , by using his key device  100  having Bluetooth™ ID 0x00223af3 by fast stage-1 authentication during working days between 07:00 and 15:00. He is also granted a temporary stage-1 authority on 24 Mar. 2005 between 19:00 and 22:00. If he arrives at the door outside of these stage-1 time slots, he may still access the door  150  at any time (00-24), but in such a case he must go through a more complex stage-2 authentication which involves additional authorization, namely by providing a PIN code from the key device  100  and having it communicated to the lock device  140  over a two-way Bluetooth™ communication link. Stage-2 authentication requires a special software in the key device  100 , since data exchange is involved. Therefore, if mobile terminals are used as key devices, they are preferably of an advanced model provided with a suitable operating system, such as Symbian, at least for users that require stage-2 authentication. As regards the PIN code, it may either be prestored in memory in the key device  100  and fetched by the software therein upon communication to the lock device, or the software may invite the user to enter his PIN code manually on e.g. the keypad  204   a  upon establishment of the two-way Bluetooth™ communication link. In other embodiments, if biometric data instead of PIN code is used as verification data, they are treated in the corresponding way, i.e. either prestored in memory or read by e.g. the fingerprint sensor  204   c . It is to be observed that all communication between key device and lock device is encrypted in accordance with an encryption algorithm, such as Blowfish. Therefore, data integrity is ascertained. 
     As for user Johan, only stage 2-authentication is available to him, and only on weekends between 10:00 and 18:00. 
     With reference to  FIG. 8 , assuming that the lock device  140  is in sleep mode, the initial wake-up stage  610  is performed in steps  612 ,  614  and  616  by using the proximity sensor  324  to detect the presence of the user of key device  100  near the lock device  140  and in response generate the wake-up control signal  326  to the CPU  313 . 
     This causes the CPU  313  to enter the first authentication stage  620 . A step  622  searches for Bluetooth™-enabled devices by paging, i.e. sending inquiry requests at regular intervals. Each Bluetooth™-enabled device within operating range (i.e. within a radius of some meters from the lock device  140 , depending on e.g. the output power of the Bluetooth™ radio module  309  and the performance of the Bluetooth™ transceivers in the devices paged for) will transmit an inquiry response to the lock device. It is checked in step  624  whether at least one inquiry response is received within a time limit; if not a time out  626  occurs and the lock device  140  returns to sleep mode. 
     If an inquiry response was received, step  628  proceeds to determine the Bluetooth™ address from the inquiry response. Moreover, a current time is determined by reading a value from the real-time clock  304 . 
     Then, the CPU  313  proceeds in step  630  to check whether the determined Bluetooth™ address of the responding device matches one of aforedescribed authentication data records in the LD-DB  142 . In case of a match, it is also checked whether the current time falls within any stage-1 time slot defined for that Bluetooth™ address. If the outcome of these checks is fully positive, as checked in step  632 , the CPU  313  proceeds to step  634  and generates the control signal  307   a  to the motor controller  307 . As described above, this will cause unlocking of the door lock  160  and allow the door  150  to be opened. 
     If the check in step  632  reveals that the determined Bluetooth™ address is not present in the LD-DB  142 , or that the Bluetooth™ address is present but the current time matches neither a stage-1 time slot nor a stage-2 time slot for that address, then the door lock  160  will not be unlocked, and the execution will return to step  622 . In some embodiments it is possible to list certain undesired Bluetooth™ addresses as explicitly forbidden in LD-DB  142 . If the determined Bluetooth™ address matches such a forbidden Bluetooth™ address, appropriate action may be taken in a step  636 , such as generating an alarm signal or registering the access attempt in memory  311  for later reporting. 
     If the check in step  632  reveals that the determined Bluetooth™ address is present in the LD-DB  142 , but that the current time does not fall within any stage-1 time slot defined for that Bluetooth™ address but only within a stage-2 time slot, the execution proceeds to step  640 . 
     In step  640 , the CPU controls the Bluetooth™ radio module  309  to establish a two-way Bluetooth™ communication link with the key device  100  detected in step  628 . In step  642 , data transmitted by the software in the key device  100  is received in the lock device  140 . Step  644  extracts verification data, such as a PIN code for key device  100 , which as previously explained is included in the received data. Then, in step  646  it is checked whether the extracted verification data matches the corresponding authentication data stored for the key device&#39;s Bluetooth™ address in LD-DB  142 . In case of a match, step  648 , the CPU  313  proceeds to step  650  and generates the control signal  307   a  to the motor controller  307 . Again, this will cause unlocking of the door lock  160  and allow the door  150  to be opened. 
     Once there is an established two-way Bluetooth™ communication link between key device  100  and lock device  140 , i.e. upon completion of step  640 , it is possible to use this link for exchanging also other kind of data than aforesaid verification data. As seen in  FIG. 7 , it may be checked in a step  710  whether the data received from the key device  100  contains authentication data updating information for the intention of updating the authentication data records stored in LD-DB  142 , for instance in order to reflect the addition of a new user/key device at the system server  122 , or a change in authority for an existing user—e.g. a change in its stage-1 or stage-2 time slot. 
     Such updating information may have been distributed to the key device  100 , as well as to other key devices in the system, from the system server  122  over the mobile telecommunications network  110 , for instance as an attachment in an MMS or email message. Updating information originating from the system server  122  (system DB  124 ) is encrypted before transmission to the key device  100  (if not already when stored in system DB  124 ), and upon reception the key device  100  stores the updating information as an encrypted dataset in local memory (KD-DB  102 ). Thus, the updating information is not decrypted by the key device  100 , which prevents unauthorized manipulation of the information. For further data security, a system time stamp is preferably included in the updating information distributed from the system server  122 , and the key device may store the updating information with a key device time stamp in its KD-DB  102 , said key device time stamp representing the time of receipt of the updating information from the system server in the key device. 
     If in step  712  updating information is found to exist in the received data, the CPU  313  proceeds to step  714  so as to update the contents of the LD-DB with the updating information received from the key device  100 . Before this is done, however, the CPU  313  preferably determines a time stamp of the received updating information, such as the aforementioned system time stamp and/or key device time stamp, and compares it or them to a current time stamp for the present authentication data in the LD-DB  142 . Only if according to this comparison the updating information from the key device  100  is newer will the actual update in LD-DB  142  take place. For improved security, the CPU  313  may choose to allow updating of the LD-DB  142  only if the current time stamp of the LD-DB  142  is older than both the key device time stamp and the system time stamp, and if the key device time stamp is newer than the system time stamp. 
     Performing such updating of the LD-DB  142  prior to performing the authentication check of the key device  100  in step  646  allows the key device to bring about updating information that may actually change the outcome of its own authentication. For instance, if the key device  100  belongs to a new user which has not previously been represented in the LD-DB, it may nevertheless bring about updating information that will give itself stage-1 or stage-2 authority after the update of the LD-DB. A condition is, of course, that authentication data for that key device has been duly created by the administrator at the server  122  and has reached the key device  100  prior to the arrival thereof at the lock device  140 . To this end, in some embodiments, step  632  will be followed by an attempt for stage-2 authentication in step  640 , even if no matching Bluetooth™ address is found during stage-1 authentication. 
     Another optional step  716  involves compiling historic data about previous accesses to the door  150  through the lock device  140 . Such historic data may have been created by the CPU  313  each time a key device has been subjected to authentication by the lock device  140  and may comprise the detected Bluetooth™ address of each such key device, and a time stamp representing the time it happened. Such historic data may be stored in an event register in the LD-DB  142 . In step  716 , a log file and/or statistics may be generated by reading the historic data from the event register. The log file and/or statistics is/are transmitted as a dataset to the key device  100  in step  718 . Upon receipt thereof, the software in the key device  100  may store the dataset in its KD-DB  102  for immediate or later forwarding to the system server  122  over the mobile telecommunications network  110 , essentially like the distribution of aforesaid updating information but in the reverse order and direction. In this way, at the system server the administrator may analyze such log file and/or statistics not only for the lock device  140  but also for other lock devices in the system, thereby being given an overview of the operational situation in the entire system. 
     In some embodiments, after a successful stage-1 unlocking in step  634 , the execution may proceed to step  638 , in which a two-way Bluetooth™ communication link is established, and then with the above-described steps of  FIG. 7  so as to exchange authentication data updating information and/or statistics/log file data with the key device  100 . 
     In an alternative embodiment, the lock device  140  is physically divided into two units. A first unit, capable of wireless communication such as Bluetooth™, is mounted at a nearby mains power socket to receive electric power therefrom. Thus, the first unit need not be optimized in terms of power consumption. The first unit is capable of performing the afore-described first and, if applicable, second authentication stages for an available key device and generate a control signal to a second unit, which will be mounted at the lock in question and cause unlocking of its lock mechanism upon receipt of a successful control signal from the first unit. Thus, the second unit will contain the electromechanical elements necessary to perform this task. The second unit is advantageously battery-powered and adapted to receive the control signal from the first unit over a wireless interface, such as Bluetooth™. Since power consumption is not an issue for the first unit, this may advantageously be adapted to scan continuously for key devices in the neighborhood, i.e. the wake-up arrangement described above may be dispensed with. This allows further miniaturization and simplification of the second unit. One first unit may be configured to handle and control several second units, each mounted at a respective door, window, etc—the first unit thereby functioning like a central locking device. 
     The invention has mainly been described above with reference to a few embodiments. However, as is readily appreciated by a person skilled in the art, other embodiments than the ones disclosed above are equally possible within the scope of the invention, as defined by the appended patent claims. For instance, even if the disclosed embodiments relate to opening of doors, the invention may just as well be used for controlling other kind of objects, including but not limited to garage ports and various other equipment at homes, offices or public buildings. For instance, the invention may be used for wireless actuation of a safety lock of the well known “safety chain” type, i.e. a lock which has three primary positions: a locked position, an open or unlocked position, and a safety position in which the protected door, window, etc, can be opened only a short distance. One example of such a safety lock is found in WO 04/083576. 
     Further, even if the disclosed embodiments use Bluetooth™ for the short-range wireless data communication, another communication standard is also feasible, including but not limited to WLAN or HomeRF. Further, in the illustrated embodiments the lock device has been exemplified by an external device, mounted to a door blade. It should be understood, however, that the inventive concept is applicable for incorporation in lock cases, such that a lock case having features according to the inventive concept may be accomplished.