Lock control system, lock controller, and key device

A lock is operated by a lock controller that receives identifying signals transmitted from one or more wireless key devices. Weights are assigned to the identifying signals, and the lock is operated only if the weights of the received identifying signals satisfy a condition, such as a threshold condition applied to their sum. The weights are preferably assigned by counting the number of times each identifying signal is registered in the lock controller. The count may be kept in the lock controller or in the wireless key device itself.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a lock control system, a lock controller, and a key device, more particularly to a system in which a plurality of key devices, used individually or in combination, control the opening and closing of a lock.

2. Description of the Related Art

Doors are customarily locked and unlocked by the use of a key. The traditional method of locking or unlocking a door is to insert the key into a keyhole by hand and then turn or press the key. A problem with this method is that it is difficult for a person who is manually or visually impaired. This problem particularly affects senior citizens, whose hand and arm functions and vision tend to deteriorate with advancing age. In today's aging society, this is a problem that needs to be solved.

One proposed solution is a lock operation system in which the entrance door to a dwelling is locked and unlocked by a lock controller that receives a signal from a wireless key device. A description can be found in, for example, Japanese Unexamined Patent Application Publication No. 2001-132293. When a user of this proposed system presses a button on the wireless key device, the device sends an identifying signal to the lock controller. When the lock controller receives this signal, it decides whether the signal was sent by a device authorized to operate the lock. If it was, the lock controller changes the lock either from the locked state to the unlocked state or from the unlocked state to the locked state. A user of this system can easily lock or unlock the door without having to insert a conventional key, and by pressing the button at a distance from a plurality of similar doors, thus the user can easily find the door which the key device can unlock.

This system can be modified so that the lock is operated by a plurality of wireless key devices, each transmitting a different identifying signal. For maximum security, the system can be designed so that all of the wireless key devices are necessary to operate the lock. Alternatively, the lock can be made to respond to signals transmitted from, for example, an arbitrary majority of the wireless key devices, so that even if some of the key devices are lost, the lock can still be operated, provided that not too many of the key devices are lost. The system may also be adapted so that any one of the wireless key devices can operate the lock.

This plural-key system becomes more flexible if different weights can be assigned to the different wireless key devices. For example, if key devices that can be easily lost or misplaced are given relatively small weights, the lock can still be operated even if all of these key devices are lost, provided enough of the other key devices remain. There are, however, two problems with such a weighting scheme.

The first problem is one of convenience and practicality. Assigning weights to the key devices is a troublesome procedure for the user, and it is moreover a procedure that has to be repeated, for all key devices, whenever the number of key devices is increased.

The second problem is that when the user assigns weights, the weights are assigned subjectively, with no guarantee that the assigned weights are appropriate. Frequently, a key device which the user thinks will never be lost, does in fact become lost. Thus, it is possible that the user may assign an inadvisably large weight to an easily losable key device.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a lock control system, a lock controller, and a key device which enables a lock to be locked and unlocked by the use of a plurality of key devices to which weights can be flexibly assigned without requiring troublesome operations by the user.

The invention provides a lock control system including a lock device and at least one key device transmitting a unique signal to a receiver, and a weight memory in which the unique signal transmitted by each key device is registered by storing a weight indicating the importance of the unique signal. An authentication unit reads the weights of the unique signals received by the receiver from the weight memory, thereby deciding whether authentication passes or fails. If authentication passes, a lock operating unit changes the lock from the locked state to the unlocked state, or from the unlocked state to the locked state.

The invention also provides a lock controller including a receiver, a weight memory, an authentication unit, and a lock operating unit as described above.

The unique signal transmitted by the key device is stored in the key device. Typically there are two or more key devices, each storing a separate unique signal. The weights stored in the weight memory to indicate the importance of the unique signals may be calculated from the number of times each unique signal is registered. The calculated weights can also be changed from time to time to enhance the security of the lock.

The invention further provides a key device having a unique signal memory storing the unique signal transmitted by the key device, a registration detector for detecting whether the unique signal has been registered in a lock controller, and a counter for keeping a count indicating the number of times the registration detector detects that the unique signal has been registered. The count is stored in a memory in the counter. A transmitter in the key device transmits the signal stored in the unique signal memory and the count stored in the counter to the lock controller. The lock controller accordingly does not have to keep count of the number of times each unique signal is registered, and the key device can be accurately weighted by a plurality of lock controllers.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the invention will now be described with reference to the attached drawings, in which like elements are indicated by like reference characters.

First Embodiment

Referring toFIG. 1, the first embodiment is a lock control system comprising a lock101with conventional lock functions, a lock controller102by which the lock can be controlled, and three key devices103a,103b,103c, an arbitrary one of which will be referred to below as a key device103.

Each key device103stores a unique key identifier (ID) and has a transmitter for transmitting the ID to the lock controller102for purposes such as registration and authentication. In the following description, the ID of key device103ais ‘101235’, the ID of key device103bis ‘234213’, and the ID of key device103cis ‘4055258’.

The lock controller102comprises a communication unit104that receives the IDs transmitted by the key devices103a,103b,103c, an authentication unit105that authenticates the IDs received by the communication unit104, a key ID combination database106that stores key IDs and combinations thereof, a key ID registration unit107that registers the key IDs and combinations in the key ID combination database106, a lock operating unit108that operates the lock101at the direction of the authentication unit105, and a key weighting control unit109that generates information for assigning weights to the key IDs.

The lock101is connected to the lock operating unit108, and changes between the locked state and the unlocked state in response to operations performed by the lock operating unit108. The lock101can also be locked and unlocked by use of a conventional manually inserted key, and can thereby be locked and unlocked even if the lock controller102is disabled by, for example, a power failure.

Referring toFIG. 2, the key weighting control unit109comprises a key ID registration count database201that stores the number of times that the different key IDs have been registered, and a key ID registration counter202that counts these numbers of times.

Referring again toFIG. 1, in the lock controller102, the communication unit104is connected to the authentication unit105, to which it sends each key ID received from a key device103.

The authentication unit105, which includes a weight table151and a weight calculation unit152, is connected to the key ID combination database106, the lock operating unit108, and the key ID registration count database201. The authentication unit105authenticates the combination of key IDs received at the communication unit104by referring to data stored in the key ID combination database106and weight table151and sends the result to the lock operating unit108.

Using the key IDs stored in the key ID combination database106and key ID registration counts stored in the key ID registration count database201, the weight calculation unit152in the authentication unit105calculates key ID weights representing the importance of the respective key devices. The authentication unit105stores the calculated weights in the weight table151, which is updated every time a key is registered. The authentication unit105receives key IDs from the communication unit104, refers to the weight table151to determine the corresponding weights, and authenticates the key IDs based on their weights. The details of the authentication process will be described later.

The key ID combination database106, which is connected to the authentication unit105and the key ID registration unit107, stores key IDs or combinations thereof that have been received from the key ID registration unit107, and provides the key IDs or combinations thereof to the authentication unit105for authentication purposes.

The key ID registration unit107, which is connected to the key ID combination database106and the key ID registration counter202in the key weighting control unit109, registers the key IDs of the key devices103and notifies the key ID registration counter202that this has been done. Exemplary key ID registration methods are manual input from a numeric keypad and automatic input by a communication link, but the possible methods are not limited to these.

The lock operating unit108, which is connected to the authentication unit105and the lock101, changes the state of the lock101from locked to unlocked, or vice versa, in response to acknowledgement of successful authentication from the authentication unit105.

The key ID registration count database201in the key weighting control unit109is connected to the authentication unit105and key ID registration counter202. On command from the key ID registration counter202, the key ID registration count database201stores the registration count of a key device103; if queried by the authentication unit105, the key ID registration count database201returns the registration count of the key device103.

The key ID registration counter202is connected to the key ID registration unit107and the key ID registration count database201. The key ID registration counter202increments the registration count of a key device103whenever notified by the key ID registration unit107that the key ID of the key device103has been registered, and commands the key ID registration count database201to store the new count value.

The components of the lock control system described above operate by the following procedure.

The key ID registration unit107registers the key IDs of the key devices103a,103b, and103c(101235, 234213, and 4055258, respectively) in the key ID combination database106in advance as shown inFIG. 3. The key ID registration unit107also sends these key IDs to the key ID registration counter202in the key weighting control unit109.

When notified by the key ID registration unit107that the key ID of a key device103has been registered, the key ID registration counter202searches the key ID registration count database201for the registration count of the key device103and increments the count value, updating the key ID registration count database201.

In the following description, the registration count of key device103ais two (2), and the registration counts of key devices103band103care one (1), as shown inFIG. 4.

When a user carrying a key device103approaches the relevant door, the key device103senses the approach by sensing that the distance from the key device103to the lock controller102installed in the door is within a predetermined value, and transmits its key ID to the communication unit104in the lock controller102. Various methods of sensing the approach of the key device103to the lock controller102are available, including manual input by the user. For example, the user may press buttons (not shown inFIG. 1) on the plurality of key devices103with registered key IDs simultaneously, or substantially simultaneously, to have the corresponding key devices103send their key IDs to the communication unit104in the lock controller102. Another possible method is one-way or two-way periodic transmission of sensing signals between the key device103and the lock controller102followed by mutual responses when the key device103approaches within the predetermined distance.

The communication unit104sends the one or more received key IDs to the authentication unit105for authentication. If authentication succeeds, then the authentication unit105notifies the lock operating unit108, which locks or unlocks the lock101.

Authentication succeeds if the key ID or IDs received from the communication unit104are stored in the key ID combination database106, and the sum of their weights exceeds a predetermined threshold value. The weights are the weights stored in the weight table151, which have been assigned by the weight calculation unit152based on the key ID registration counts stored in the key ID registration count database201. The weights may be equal to or proportional to the registration counts. InFIG. 4, for example, the weight calculation unit152may assign weight two (2) to key device103a(key ID: 101235), and weight one (1) to key devices103b(key ID: 234213) and103c(key ID: 4055258).

The threshold value for determining that authentication succeeds can be defined as, for example, fifty percent (50%) of the sum of the weights of all the key IDs registered in the key ID combination database106. If the weights are equal to the registration counts inFIG. 4, accordingly, the threshold value is determined as follows.
Threshold value=(2+1+1)×(50/100)=2

In this case, authentication succeeds if the sum of the weights of the key IDs (or the weight of the single key ID) received from the communication unit104is two or more. The key ID combinations that pass authentication are therefore the following five: (101235), (101235 and 234213), (101235 and 4055258), (101235, 234213, and 4055258), and (234213 and 4055258). In other words, the lock can be operated by key device103a, by any combination including key device103a, or by the combination of key devices103band103c. Neither key device103bnor key device103ccan operate the lock alone, however, because the weights of their key IDs are less than the threshold value (2).

As described above, the lock control system in the first embodiment assigns weights to the key devices103according to their key ID registration counts, without requiring the user to assign weights to the key devices103directly.

A key device103having a comparatively high key ID registration count in the lock controller102is likely to be frequently carried and used by the user, and is correspondingly unlikely to be misplaced or lost. Therefore, the lock control system assigns comparatively high weights to key devices103with high key ID registration counts. In the example above, one such key device103areceives a weight high enough that it can operate the lock by itself.

A key device103having a comparatively low key ID registration count in the lock controller102is less likely to be frequently carried and used by the user, and is therefore more likely to be misplaced or lost. Such a key device103is assigned a comparatively low weight and cannot operate the lock by itself. Therefore, if the user loses the key device103, the lock cannot be operated by a third party who has unlawfully or accidentally obtained the key device103. In the example above, key devices103band103chave low registration counts and weights. The user can keep these key devices as spares, in the event that the key device103athe user normally uses is lost, without the worry that the loss or theft of a single spare key device might compromise the security of the lock.

The automatic weighting of key IDs in the first embodiment is particularly useful when there are many key devices103, or when the user occasionally changes the key device103or combination of key devices103that he or she normally uses. Manual input of weights in these cases would be a considerable inconvenience. By changing the key device103or combination of key devices103that he or she normally uses from time to time, the user can improve the security of the lock system without any loss of convenience. That is, the user can vary the signals that operate the lock101just by changing the combination of key devices103normally carried, with no extra effort required, because the weights stored in the weight table are updated automatically each time a key device or combination of key devices is registered.

By providing automatic weighting of key devices103, the first embodiment also prevents the key devices103from being weighted inappropriately by the user.

Second Embodiment

Referring toFIG. 5, the lock controller102in the second embodiment comprises a communication unit104, an authentication unit105, a key ID combination database106, and a lock operating unit108as in the first embodiment, but replaces the key ID registration unit and key weighting control unit of the first embodiment with a data registration unit502and a key ID registration count database503. The second embodiment also employs key devices501a,501b, and501cdiffering from the key devices of the first embodiment. An arbitrary one of these three key devices will be referred to below as a key device501.

As in the first embodiment, each key device501has wireless communication functions and stores a unique key identifier (ID) that it transmits to the lock controller102for purposes such as registration and authentication. In the following description, the ID of key device501ais ‘101235’, the ID of key device501bis ‘234213’, and the ID of key device501cis ‘4055258’. In the second embodiment, each key device501keeps a count of the number of times it has been registered and transmits its latest registration count to the lock controller102together with its key ID.

Referring toFIG. 6, a key device501comprises a communication unit601for communicating with the lock controller102, an ID memory602for storing the key ID, a key ID registration counter603for keeping the ID registration count in an internal memory, and a key ID registration detector604for detecting that the key ID has been registered in the lock controller102.

The communication unit601is connected to the ID memory602, the key ID registration counter603, and the key ID registration detector604. In response to requests from the lock controller102or operations by the user, the communication unit601sends the lock controller102the key ID stored in the ID memory602and the registration count stored in the key ID registration counter603. The communication unit601also notifies the key ID registration detector604when the key ID is registered in the data registration unit502.

The ID memory602, which is connected to the communication unit601, sends the communication unit601its stored key ID on request from the communication unit601.

The key ID registration counter603is connected to the communication unit601and the key ID registration detector604. When the key ID registration detector604detects the registration of a key ID, the key ID registration counter603increments its key ID registration count. The key ID registration counter603sends the key ID registration count to the communication unit601on request from the communication unit601.

The key ID registration detector604, which is connected to the key ID registration counter603and the communication unit601, monitors the communication unit601to detect that the communication unit601has registered the key ID in the data registration unit502. When the key ID registration detector604detects that the key ID has been registered in the lock controller102, it notifies the key ID registration counter603.

The second embodiment is not restricted to any particular method of detecting that the key ID has been registered in the lock controller102. One possible method is manual input by the user, in which case it is not necessary for the key ID registration detector604to be connected to the communication unit601.

The data registration unit502performs the functions of the key ID registration unit107in the first embodiment, and in addition can store the registration count of each key device501in the key ID registration count database503. More specifically, the data registration unit502is connected to the key ID registration count database503and the key ID combination database106, stores received key ID combinations in the key ID combination database106, and stores received key ID registration counts in the key ID registration count database503.

The key ID registration count database503has substantially the same functions as the key ID registration count database in the first embodiment. More specifically, the key ID registration count database503, which is connected to the data registration unit502and the authentication unit105, stores key ID registration counts received from the data registration unit502, and returns the stored key ID registration counts to the authentication unit105on request from the authentication unit105.

The operation of the second embodiment will be described below, omitting descriptions of operations that are the same as in the first embodiment.

The key ID registration detector604in a key device501continuously monitors the registration of the key ID in the lock controller102through the communication unit601. Whenever the key ID registration detector604detects that the key ID has been registered in the lock controller102, the key ID registration count stored in the key ID registration counter603is incremented by one.

When the key ID is registered, the communication unit601transmits both the key ID and the corresponding key ID registration count stored in the key ID registration counter603to the lock controller102, where the data registration unit502carries out the registration process.

The registration process will now be described in more detail. In the following description, the key ID registration count stored in the key ID registration counter603in key device501ais two (2), and the key ID registration counts stored in the key ID registration counter603in key device501band key device501care one (1).

When the key devices501a,501b, and501cregister their key IDs, these registration counts are first sent, together with the corresponding key IDs, to the data registration unit502in the lock controller102. The key IDs are then stored in the key ID combination database106as shown inFIG. 3; the key IDs and the corresponding registration counts are stored in the key ID registration count database503.

At the completion of registration, the key devices501a,501b, and501cincrement the corresponding key ID registration counts stored in the key ID registration counter603of each key device.

The authentication unit105uses the information stored in the key ID combination database106and the key ID registration count database503to carry out authentication in the same way as in the first embodiment, by assigning weights to the key IDs.

By having each key device501count the number of times its ID has been registered in the lock controller102as described above, the lock control system in the second embodiment provides the same effects as in the first embodiment. In assigning weights to the key IDs in the first embodiment, however, the lock controller102counts only the number of times it has registered the key IDs itself. In the second embodiment the same key device501can be used with a plurality of lock controllers102, each of which will assign weights according to the number of times the key device501has been registered in all of the lock controllers102. The assigned weights will therefore reflect the frequency of use of the key devices501, as desired, rather than the frequency of use of the lock controllers102.

In the second embodiment, a key device501may also calculate its own weight by using its key ID registration count and transmit the calculated result instead of the key ID registration count to the lock controller102, eliminating the need for weight calculation by the authentication unit105in the lock controller102.

This invention is not limited to the embodiments described above. Further possible variations include, for example, the following.

Instead of using the key ID registration count of a key device as its weight, as in the first and second embodiments, the authentication unit105may define one or more threshold values, set weights for ranges bounded by the threshold values, and assign a weight to a key device by comparing its ID registration count with the defined threshold values.

In the first and second embodiments, authentication passes (succeeds) when the sum of the weights of the key IDs received from the communication unit104exceeds fifty percent (50%) of the total weight of all registered key IDs, but similar effects are obtained if the pass-fail threshold is different from fifty percent.

The first and second embodiments include three key devices each, but the number of key devices may be increased.

Even when the authentication unit105in the first and second embodiments receives only a single key ID from the communication unit104, it may determine that authentication has succeeded if the weight of the key ID exceeds the pass-fail fail threshold value. In a variation of these embodiments, the authentication unit105may be adapted to make authentication fail unless at least one more key ID is received. In other words, successful authentication requires at least two key devices. This variation protects a user who has lost a much-registered key device103, by ensuring that the lost key device103will be unable to unlock the lock101by itself, no matter how high its weight.

The lock control system in the first and second embodiments uses key IDs for authentication, but other unique signal data stored in a key device can also be used for the same effect.

Applications of the lock control system of the present invention are not limited to door locking and unlocking systems; other possible applications include security systems for safes and cars and locking functions for preventing unauthorized use of computers. The locks in these systems may be physical locking mechanisms such as electronic locks or software locking features for prohibiting unauthorized access.

Those skilled in the art will recognize that still further variations are possible within the scope of the invention, which is defined by the appended claims.