GB2069582A - Door locking system - Google Patents

Abstract

A remotely controlled door locking system, e.g. for a hotel, has a lock mechanism 11 at each door with a key reader 15. Reader 15 reads the code of a key inserted therein and sends the code and data identifying the respective door over a communication line 12 to a central control 10 which compares the code and data with preassigned codes in a store 13. If the key code is correct a lock release signal is sent back on the line 12 to operate a door release 31 to allow the door to open. An alarm 27 can be generated if the code of the key is wrong or if a door switch 32 detects door opening in the absence of a door release signal. A pressure mat 35 can prevent an alarm being generated when the door is opened from the inside. <IMAGE>

Description

SPECIFICATION Door locking apparatus The present invention is concerned with door locking apparatus.

It is the normal practice in establishments such as hotels for each room in the hotel to have a mechanical lock. On registering with the hotel and being assigned to a particular room, a guest is usually given the key to operate the lock for that room. On leaving the hotel, the guest is expected to return the key for the use of the next guest to occupy the same room. Normally the mechanical lock for any particular room will remain unchanged for a considerable period of time. This produces a security risk in that it is known for persons legitimately occupying a hotel room for, say, one night, to obtain a copy of the key to the room and retain the copy when they hand in the original key on departing the hotel. This copy of the key can then be used at some later time to gain access to the particular hotel room when the room is occupied by some other guest.A number of hotel room thefts are believed to result from this deception.

Electronically operable locks for doors are also known. Some such locks operate in response to the insertion of a magnetically coded card in a card reading slot in the architrave of the door. However, normally such locks are individually coded to respond always to the same coded key or card to release the door lock.

According to the present invention, door locking apparatus for controlling locking of a plurality of doors, comprises a plurality of coded keys for opening the doors, a control station having a store and data entry means for lodging in the store data defining the codes of the keys assigned to respective selected doors, remotely controllable lock mechanisms at each of the doors to permit opening of the door in response to application of the respective assigned key, and communication means for data communication between the lock mechanisms and the control station; each lock mechanism having means responsive to application of a key to send a key code read signal to the control station over the communication means and transmit data defining the code of the key, the control station being responsive to the key code read signal from the lock mechanism to read the key code data and identify the respective door, to compare the received key code data with the code in the store of the assigned key for the respsctive door and to send over the communication means a lock release signal to. the respective lock mechanism if the received code matches the stored code; each lock mechanism having means responsive to a lock release signal for the respective mechanism to release the lock to permit the door to be opened. With this arrangement the release of the locking mechanism is controlled remotely from the control station.If such an apparatus is installed in a hotel for controlling the locks of guest room doors, the control station may be at the reception area of the hotel. Then, when a guest initially books in to the hotel, he may be assigned a key randomly selected from a pool. On being assigned the key, the identity of the key is entered by the data entry means at the control station to lodge in the store the code of the assigned key against the room identity, e.g. the number, of the room the which the guest is assigned. In this way, the door locking apparatus is automatically programmed on booking in of a guest thenceforth automatically to permit the guest's entry to his assigned room when he uses his assigned key.

It can be seen that by this arrangement, when.the guest vacates the room, a fresh key can be assigned to the next guest to occupy the room and the apparatus recoded for the new key. In this way even if the preceding guest did not hand in his key, it would no longer serve to open the room that he had occupied.

Preferably, the control station is arranged to generate an alarm if the received code does not match the stored code. In this way any attempt to open a guest room door using a key other than that specifically assigned to the respective room generates an alarm at the control station to alert the hotel staff.

Preferably also, each lock mechanism has means responsive to opening the respective door to generate a door opening signal and alarm logic circuitry arranged to generate an alarm signal on receipt of said door opening signal in the absence of the lock release signal. This arrangement also generates an alarm if any attempt is made to open the guest room door except by using the proper key which would generate the lock release signal. With this arrangement, the normal mechanical lock of the guest room doors can be retained with the remotely controllable lock mechanism conveniently releasing a striking plate in the architrave so that the door can be opened without operating the mechanical lock. However, if the automatic locking apparatus should break down or be unservicable, the room doors can still be opened using a ordinary mechanical key.Any unauthorised use of such a mechanical key whilst the door locking apparatus was operating normally would, however, trigger an alarm in response to generation of the door opening signal. The alarm logic circuitry conveniently generates as the alarm signal a key code read signal and sends it to the control station. This would cause the control station to read the key code data generated by the lock mechanism. In the absence of a key applied to the lock mechanism, the key code read by the control station will not match the stored code so that an alarm will be generated.

Conveniently, each lock mechanism includes a manual release handle for opening the door from inside and there is provided means for detecting that the door is being opened from inside, the alarm logic circuitry being arranged to inhibit the generation of said alarm signal in response to said means for detecting so as not to generate an alarm signal when the door is manually opened from inside. Said means for detecting may be a pressure-sensitive mat on the floor inside the door. Then, the occupant of a room can manually open the door from inside using the handle without setting off the alarm, because in order to reach the interior door handle, the occupant must stand on the pressure-sensitive mat.

In one embodiment, said door opening responsive means comprises a magnet on one of the door or the surrounding architrave and a magnetic field responsive device on the other, the magnet and the device being positioned so that the device responds to the proximity of the magnet providing a door closed signal only when the door is closed. Then, said door opening responsive means may have a pulse generator arranged to generate a door opening signal pulse in response to loss of said door closed signal when the door is opened.

Since only a pulse signal is generated to indicate that the door is being opened, the lock release signal need be supplied only for the duration of the door opening pulse to avoid setting off the alarm when the door is opened legitimately. Normally, the lock mechanism releases the lock of the door only so long as the lock release signal is generated and the control station is arranged to generate the lock release signal until the key is withdrawn. Thus, to gain access to a room, the guest inserts the key, pushes the door open when the lock is released and then withdraws the key.

Preferably, the apparatus includes a door release switch in each room accessed by said plurality of doors at a position in the room remote from the door, the switch being manually operable to generate the lock release signal to unlock the door. For hotel rooms, the door release switch may be a push-button conveniently placed to enable the guest to unlock the door whilst still in bed.

Examples of the present invention will now be described with reference to the accompanying drawings in which: Figure 1 is a block schematic diagram illustrating the main functional parts of the central control station and a typical room installation of an embodiment of the door locking apparatus of the present invention; and Figure 2 is a circuit diagram illustrating the release mechanism and alarm logic of a typical lock mechanism. The described example is designed especially for use in hotels for controlling the locking of the doors to the various guest rooms of the hotel. The locking apparatus is controlled from a central control point 10 in the hotel which may typically be at the reception or checking-in desk of the hotel.In each guest room of the hotel controlled by the apparatus there is provided a room installation 11 which includes the remotely operable door lock components. The room installations 11 of each of the guest rooms is in data communication with the central control point 10 by means of a common communication bus 1 2.

The bus 1 2 may conveniently comprise the coaxial cable installation common in hotels for supplying television signals from a common hotel aerial to television receivers in each guest room. By a suitable modulation of data information on a high frequency carrier signal, data can be sent over this coaxial cable installation without interfering with the usual television signals.

With the described apparatus, the lock of any particular guest room door can be programmed to respond only to a particular key assigned to a guest who is to take the room.

Thus, when a guest checks into the hotel and is assigned a particular guest room, he is handed by the receptionist a key randomly selected by the receptionist from a pool of keys. Before handing over the key, the receptionist inserts the key into a key reader provided adjacent a keyboard and video display unit 14. Then, the receptionist enters the number of the room assigned to the guest on the keyboard and causes the code of the key read by the key reader to be loaded into a store 1 3 against the relevant room number. It will be appreciated that the store 1 3 and keyboard and video display unit 14 may form part of an electronic computer apparatus.Similarly, the other functional parts of the central control point 10 described hereinafter may also form part of the computer apparatus which is appropriately programmed to perform these operations. The room number and key identifying number entered by the receptionist are retained in the store in such a way that the equivalent key code of the key assigned to any particular occupied room of the hotel can be read from the store 1 3 by the apparatus as required simply by identifying the relevant room number. Once the key code has been loaded into the store 13, the door locking apparatus will thereafter operate to respond to that key being inserted in the lock mechanism of the particular guest room to release the lock mechanism and permit entry.

The room installation 11 of each room has a key reader 1 5 which is adapted to receive the keys used in the apparatus and read the coding of the keys. Any convenient form of keys and key reader may be employed in the present apparatus. A preferred form comprises plastic keys having mechanical edge coding, rather similar to the usual mechanical keys.

The preferred plastic keys have slots at predetermined locations along their lengths and the key reader 1 5 is designed to identify whether the slots are present or absent at the various slot locations along the key edge. Thus, the key reader 1 5 provides a binary code identifying the key being read. Also, when the key is fully inserted into the key reader 15, the reader provides a strobe signal to indicate that the key has been inserted and a key code is ready to be read.The strobe signal is supplied from the key reader on a line 1 6 to a communications interface 1 7. The communications interface 1 7 is arranged to convert the binary data generated in the room installation for transmission along the communication bus 1 2. With the preferred coaxial cable bus 12, the interface 17, therefore, generates a high frequency carrier signal and coverts the data to be transmitted into modulations of this carrier. The central control point 10 also communicates with the bus via an interface unit 1 8 which demodulates the received carrier signals on the bus 1 2 and supplies them to the control point 10 as binary data signals along a data line 1 9.

On receiving the strobe signal on the line 16, the communications interface 1 7 communicates with the central control point 10 to indicate that a key has been inserted in the key reader 1 5 of that particular room. At the same time, the communications interface 1 7 loads the key code data supplied from the reader 1 5 on a multi-bit bus 20 into a buffer in the interface 1 7. The control point 10 responds to the strobe from the key reader 1 5 by initiating further communication with the interface 1 7 to read the contents of the key code buffer in the interface 1 7.

Considering again the operation of the central control point 10, a control unit 21 responds to the strobe received from the communications interface 1 7 via the interface 1 8 to initiate a data read and decode function 22 which reads the key code from the buffer in the interface 1 7 of the particular room installation 11. Having read the key code, the unit 22 decodes the data received and supplies the key code that it has read to a comparator 23 along a line 24. At the same time, the unit 22 identifies the relevant room number and a store address generator 25 generates the address of the corresponding location in the store 1 3 containing the correct key code for that room number as originally loaded by the receptionist when the guest checked in.The key code contained in the store 1 3 at the location identified by the store address generator 25 is then read from the store and supplied also to the comparator 23 along a line 26. The stored key code is compared in the comparator 23 with the received key code supplied by the unit 22. If the codes do not match, the comparator 23 sends a signal to an alarm generator 27 to generate an alarm.

However, if the codes do match, a door release signal is supplied by the comparator 23 along a line 28 and is encoded in an encoder 29 for transmission via the interface 1 8 on the communication bus 1 2 to the particular room installation 11. The communications interface 1 7 of the room installation 11 responds to the door release signal received over the bus 1 2 by generating a door release pulse on a line 30 supplied to a door release mechanism 31. The door release mechanism 31 may comprise any arrangement for electronically releasing a door lock and would typically operate electromechanically by means of a solenoid.Usually, the door release signal simultaneously lights an indicator lamp near the key reader 1 5 to tell the guest that the door is now released.

The room installation 11 preferably contains various further features providing additional security and also greater flexibility. It is desirable if the normal mechanical locks of the guest room doors are retained so that the doors can be opened using mechanical keys if the automatic locking apparatus fails or if there is a failure of the electrical supply to the hotel. However, preferably the room installation 11 is arranged to cause an alarm to be raised if the room door is opened except in response to a correct key being inserted in the reader 1 5. Thus, the room installation 11 includes a door switch 32 arranged to respond to the door being opened by generating a pulse signal fed on a line 23 to an alarm logic circuit 34.A pressure-sensitive mat 35 placed inside the door also supplies a signal on a line 36 to the alarm logic circuit 34 whenever the mat senses somebody standing immediately inside the door. Further, the door release signal supplied from the communications interface 1 7 to the door release mechanism 31 is also fed along a line 37 to the alarm logic 34. The alarm logic 34 operates to generate a false strobe signal on a line 39 whenever the alarm logic 34 receives a door opening pulse on the line 33 in the absence of either a signal on the line 36 from the mat 35, or a door release signal on the line 38.

The false strobe on the line 39 is fed to the comunications interface 1 7 and is treated as a normal strobe so that the central control point 10 responds by reading the code output of the key reader 1 5. If the door is being opened without the correct key in the reader, or with no key in the reader, the code read into the central control point 10 in response to the false strobe will not correspond to the stored key strobe in the store 1 3 so that the comparator 23 will raise an alarm The room installation 11 preferably also has a bed head switch 40 which enables the occupant of the guest room to release the door without getting out of bed.The bed head switch 40 produces a door release signal on a line 41 supplied directly to the door release mechanism 31 to release the door lock and also via the line 38 to the alarm logic 34 to inhibit generation of a false strobe.

Referring now to Fig. 2, part of the room installation 11 is illustrated in greater detail; In Fig. 2, the key reader is illustrated at 50 and comprises a plurality, only four shown, of switch contacts 51 which are arranged to respond to the presence or absence of slots in the edges of the keys inserted in the key reader. Thus, for example, the presence of a slot at a particular position along the edge of a key when pressed fully home into the key reader may cause a particular set of the cony tacts 51 to close, whereas in the absence of a slot the contacts remain open. The key reader 50 also has a set of contacts 52 arranged to close in response to the key being pressed fully home in the key reader.On closing of the contacts 52 when the key is pressed fully home, the DC voltage, typically 12v, from a regulated power supply connected to terminals 53 and 54 in Fig. 2, is connected to the bus bar 55 energising one side of the contacts 51. Thus, once the contacts 52 are closed, a binary signal is generated on a multi-core cable 56 representing the code of the key inserted in the key reader. The multicore cable 56 feeds this code to the buffer in the communications interface 1 7 of Fig. 1.

Also on closing of the contacts 52, a logic "1" is applied to one input of an OR gate 57 so that the output of the gate 57 becomes a logic "1". The output of the gate 57 on a line 58 is supplied also to the communications interface 1 7 of Fig. 1 as the key read strobe.

As explained previously, in response to the strobe, the central control point 10 sends back to the communications interface 1 7 a door release signal which is decoded by the interface 1 7 and supplied to the circuit of Fig.

2 on a line 59. The line 59 is connected to the base of a switching transistor 60 so that the door release signal on the line 59 turns the transistor 60 on. The transistor 60 connects an energising voltage supply, typically of between 1 2v and 1 5v unregulated, across a door release mechanism 61, typically including a solenoid 62. The door release mechanism 61 may comprise the usual striker mechanism for deflecting on energising of the solenoid 62 the striker plate of the usual mechanical door lock so that the door can be opened. Also connected in parallel across the door release mechanism 61 is a light-emitting diode 63 preferably a green LED.The LED 63 is located on the outside of the door so as to indicate to the person inserting the key into the key reader 1 5 that the door release mechanism has operated to allow entry.

The door release mechanism 61 and the key reader 50 are normally situated in the architrave of the door immediately adjacent the usual mechanical lock of the door. Also in the architrave is located a magnetic reed switch 64 which is arranged to respond to a magnet 65 positioned to move with the door itself. The relative positions of the reed switch 64 and the magnet 65 are arranged so that the reed switch is closed in response to the magnetic field of the magnet 65 only when the door is fully closed. On opening of the door, the magnet 65 moves away from the switch 64 so that the contacts of the switch 64 open. One contact of the switch 64 is connected to the earth line of the 1 2v supply to terminals 53 and 54 and the other contact is connected via a resistor 65 to the positive line of the voltage supply and via a capacitor 66 to one input of an AND gate 67.This input of the AND gate 67 is also connected via a resistor 68 to the earth line. The values of the resistor 65 and the capacitor 66 are selected so that on opening of the contacts of the switch 64, a positive going pulse is applied to the input of the AND gate 67. If the other input to the AND gate 67 is a logic "1" then the output of the AND gate 67 is also a logic 1 pulse which is fed by the line 69 to a second input of the OR gate 57 thereby generating a false strobe on the line 58. The apparatus reacts to the generation of the false strobes as described previously. The second input of the AND gate 67 is connected to one side of the contacts of a pressure-sensitive mat identified in Fig. 2 as the switch 70. The other side of the contacts of the mat 70 are connected to the earth line.Thus, if the contacts of the mat switch 70 are closed, the second input of the AND gate 67 is held at logic "0" blocking the generation of the false strobe signal. Further, the second input of the AND gate 67 is connected via a resistor 71 to one terminal of the door release mechanism 61. If the transistor 60 is off and also a switch 72 is open as shown in Fig. 2, then the resistor 71 maintains the second input of the AND gate 67 at a logic 1. However, when the transistor 60 is turned on, the second input of the AND gate 67 is again forced to a logic 0 thereby blocking the generation of any false strobes. The switch 72 illustrates the bed head switch 40 illustrated in Fig. 1. As explained previously, the above arrangement enables the door to be opened from inside using the usual mechanical door handle without raising an alarm because the pressuresensitive mat forces one input of the AND gate to a logic 0 when the occupant of the room is standing on it. Also, the door can be opened without raising the alarm when receiving a door release signal in response to the correct key being inserted in the key reader, or in response to operating the manual bed head switch from inside the room.

In an alternative arrangement, the mechanical dbqr lock is not maintained and instead standby > }atteries are provided maintained in a charged s?te in each guest room. Then, the door lock can be released using the standby batteries either from the bed head release button or from a second button on the inside of the door architrave. In order to gain access to the room from outside, a special master key is provided which is recognised by a separate key reading circuit provided in each room installation and powered by the standby battery. In response to the master key, the lock mechanism is released automatically. If the special master key is used when the full automatic locking apparatus is operating properly, it can be arranged to generate an alarm in the usual way.Of course, if the main system is out of service or if the main power supply is off, no alarm would be raised.

In the apparatus described, the central control point may be arranged to recognise certain specific codes as master codes of keys assigned to housekeepers, etc for use in gaining access legitimately to all the rooms, for example, on one floor of the hotel. The provision of such master key coding is simply a matter of programming of the store 1 3.

It will be appreciated that the key specifically assigned to a guest on registering at the hotel is personal to the guest and fully identifies him. Thus, the key can be used in an expansion of the present system in effect as a credit card for automatic sales dispensers located around the hotel. Then, each such dispenser is provided with a key reader and a central hotel computer system is arranged to read the code of keys inserted in the key reader and automatically to debit the guest's account for the purchases being made. If the key code read at the dispenser does not match that of the issued key, then the computer prevents the dispenser from operating.

As mentioned previously, the central control point 10 may be constituted chiefly by a suitable programmed computer system in which case the functional blocks identified in Fig. 1 in fact comprise programme elements and not discrete hardware elements. The described door locking apparatus may further form part of a computer-controlled room management system for monitoring at the central control point the status of the various guest rooms of the hotel. In such a room management system, each guest room has a signalling unit arranged to receive plugs or the like inserted by the hotel staff to indicate the status of the particular room. Thus, when a chambermaid enters the room to clean it, she inserts her plug into the signalling unit which signals along the coaxial cable as described previously to the central control point computer which can display to an operator that the room is being cleaned. When the cham- bermaid is finished she withdraws her'plug.

and the central control computer notes that the room is now clean. The houskeeper may also have a different plug which the computer reads to note that the room is being inspected. In this way the status at any time of the rooms in the hotel can be monitored at the central control point.

Claims (11)

1. Door locking apparatus for controlling locking of a plurality of doors, comprising a plurality of coded keys for opening the doors, a control station having a store and data entry means for lodging in the store data defining the codes of the keys assigned to respective selected doors, remotely controllable lock mechanisms at each of the doors to permit opening of the door in response to application of the respective assigned key, and communication means for data communication between the lock mechanisms and the control station; each lock mechanism having means responsive to application of a key to send a key code read signal to the control station over the communication means and to generate data defining the code of the key; the control station being responsive to the key code read signal from the lock mechanism to read the key code data and identify the respective door, to compare the received key code data with the code in the store of the assigned key for the respective door, and to send over the communicating means a lock release signal to the respective lock mechanism if the received code matches the stored code; each lock mechanism having means responsive to a lock release signal for the respective mechanism to release the lock to permit the door to be opened.

2. Apparatus as claimed in claim 1 wherein the control station is arranged to generate an alarm if the received code does not match the stored code.

3. Apparatus as claimed in claim 2 wherein each lock mechanism has means responsive to opening the respective door to generate a door opening signal and alarm logic circuitry arranged to generate an alarm signal on receipt of said door opening signal in: the absence of the lock release signal.

4. Apparatus as claimed in claim 3, wherein the logic circuitry generates as the alarm signal a key code read signal and sends it to the control station.

5. Apparatus as claimed in claim 3 or claim 4 wherein each lock mechanism includes a manual release handle for opening the: door from inside and there is provided means for detecting that the door is being opened from inside, the alarm logic circuitry being arranged to inhibit generation of said alarm signal in response to said means for detecting so as not to generate an alarm signal when the door is manually opened from inside.

6. Apparatus as claimed in claim 5 wherein said means for detecting is a pressure-sensitive mat on the floor inside the door.

7. Apparatus as claimed in any of claims 3 to 6 wherein said door opening responsive means comprises a magnet on one of the door or the surrounding architrave and a magnetic field responsive device on the other, the magnet and the device being positioned so that the device responds to the proximity of the magnet providing a door closed signal only when the door is closed.

8 Apparatus as claimed in claim 7 wherein said door opening responsive mans has a pulse generator arranged to generate a door opening signal pulse in response to loss of said door closed signal when the door is opened

9. Apparatus as claimed in any preceding claim and including a door release switch in each room accessed by the doors, at a position in the room remote from the door, the switch being manually operable to generate the lock release signal to unlock the door.

10. Door locking apparatus substantially as hereinbefore described with reference to the accompanying drawings.

11. Any novel feature or combination of features of the apparatus hereinbefore de scribes