Abstract:
A door security system comprises a door, and a handle assembly attached to the door. The handle assembly includes a lock mechanism, a handle, and an escutcheon. The lock mechanism has an unlocked state and a locked state for securing access to the door, and the handle is rotatably supported by the handle assembly as a means of access through the door when the lock mechanism is in the unlocked state. At least one of the handle and the escutcheon acts as an antenna capable of wirelessly receiving and transmitting radio frequency signals and capable of communicating with the lock mechanism to switch the lock mechanism between the unlocked and locked state.

Description:
BACKGROUND 
       [0001]    This invention relates to security systems and more particularly relates to wireless locks for door security systems. 
         [0002]    Facilities that have a large number of inside doors include hotels and commercial buildings. Quite frequently, these types of facilities require a security system put in place to grant or deny access through individual doors inside the facility. A common lock assembly fitted to the doors includes a locking mechanism, a handle or knob on either side of the door, and an escutcheon or metal plate on either side of the door to cover and protect the handles and locking mechanism. These assemblies are typically fitted into routed cavities in the doors. All locking mechanisms have some sort of an unlocked state in which a user is allowed to open the door and a locked state in which a user is prevented from opening the door. The conventional locking mechanism is provided with a latch, which is actuated by the handle or knob. The conventional locking mechanism also includes a deadbolt which, when engaged, prevents access through the door. 
         [0003]    Some facilities rely on the method of a user controlled key in conjunction with the locks in order for a user to access certain doors. These keys can range from conventional metal keys used with cylinder locks to more modern magnetic-stripe keycards that pair with a reader on the lock mechanism. Another method of security is a numeric keypad adjacent to the door into which a user can type a code that will unlock the door and allow access. 
         [0004]    As security measures become more modernized, facilities can implement a remote system in addition to, or in place of, the user-centered systems of door control. The door lock assemblies need to have an antenna that is capable of communicating wirelessly with a controller. If a smaller antenna is used with the existing lock assembly and cavity, the efficiency of the antenna&#39;s electromagnetic (EM) radiation will not be very good. It is possible to rout a larger cavity so that a much larger antenna can be placed within the door in conjunction with the lock assembly, but commercial doors are often made out of wood or metal so retrofitting them can be costly. In addition, an antenna contained within a door&#39;s cavity, regardless if the cavity has been enlarged or not, has to permeate the door&#39;s material acting as a barrier to efficient EM radiation. Wood doors gather moisture and hinder antenna performance by absorption, refraction reflection of the EM wave. The metal doors are a shield for the transmission of EM waves. In light of this, repeaters are often placed in a building&#39;s hallways as a means of boosting the wireless performance of these door lock systems. 
         [0005]    There exists a need to boost the performance of wireless door security systems while eliminating excessive repeaters and keeping the cost down (i.e. building new doors or retrofitting existing doors). 
       SUMMARY 
       [0006]    Another aspect of the invention is a door security system comprising a control module, a door, and a handle assembly attached to the door. The handle assembly includes a lock mechanism with an unlocked state and a locked state for securing access to the door, a handle rotatably supported by the handle assembly as a means of access through the door when the lock mechanism is in the unlocked state, and an escutcheon. At least one of the handle and the escutcheon acts as an antenna wirelessly communicating with the control module and communicating with the lock mechanism to switch the lock mechanism between the unlocked and locked state. 
         [0007]    Another aspect of the invention is a door security system comprising a door, a housing attached to the door, a handle, and a control module. The housing includes a lock mechanism for securing access to the door and has an unlocked state and a locked state. The handle is rotatably supported by the housing, and acts as a means of access through the door when the lock mechanism is in the unlocked state. The handle further acts as an antenna capable of sending and receiving radio signals. The control module is capable of sending and receiving radio frequency signals to and from the handle to switch the lock mechanism between the unlocked and the locked states. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is a diagrammatical view of a wireless door security system. 
           [0009]      FIG. 2  is a block diagram of the wireless door security system of  FIG. 1 . 
           [0010]      FIG. 3  is an exploded perspective view of a remote access control system of the wireless door security system. 
           [0011]      FIGS. 4A and 4B  are alternative methods of electrically isolating a handle for use as an antenna in the wireless door security system. 
           [0012]      FIG. 5  is another embodiment of a remote access control system of the wireless door security system. 
       
    
    
     DETAILED DESCRIPTION 
       [0013]    In  FIG. 1 , wireless door security system  10  is shown and includes a plurality of doors  14 , key  16 , lock mechanism  18 , central control module  20 , and a plurality of remote access control systems  22  mounted on the plurality of doors  14 . Door security system  10  controls whether user  12  will be granted or denied access through a particular door  14 . One way user  12  is granted access through door  14  is by presenting a valid key  16  to remote access control system  22  mounted on door  14  or within lock mechanism  22 , which unlocks lock mechanism  18  and allows user  12  to open door  14  and pass through. Key  16  is typically a type of card with data stored on it; the data are usually stored in the form of a magnetic stripe that remote access control system  22  is capable of reading and determining whether the data stored on key  16  are valid. 
         [0014]    Wireless door security system  10  includes central control module  20  and a plurality of remote access control systems  22  located remotely from central control module  20 . Central control module  20  uses wireless communication technology to communicate with each remote access control system  22 . Central control module  20  can be used to program each remote access control system  22  so that certain users  12  are granted access through certain doors  14  and other users  12  are granted access through other doors  14 . With what is effectively a “lockdown” mode, central control module  20  can also deny access through any number or all of doors  14  regardless of whether user  12  presents key  16  that is normally valid. Central control module  20  can also receive information from each remote access control system  22  so that user access information such as the time and date that particular user  12  was granted access through door  14  can be tracked and monitored. 
         [0015]    As shown illustratively in  FIG. 1  and diagrammatically in  FIG. 2 , central control module  20  includes central access controller  24 , central wireless communicator  26 , and power and/or signal bus  28  that electrically interconnects central access controller  24  and central wireless communicator  26 . Central wireless communicator  26  allows information to be communicated wirelessly between central access controller  24  and each remote access control system  22 . In some cases, such as where door  14  is located substantially far away from central control module  20 , repeaters  30  help amplify the wireless communication between central control module  20  and remote access control system  22 . These repeaters  30  are, for example, mounted in the hallways of a large building in which door security system  10  is installed. Central access controller  24  is configured to communicate bidirectionally with one or more central wireless communicators  26 , as shown in  FIG. 2  by double-headed arrow  32  interconnecting central access controller  24  and central wireless communicator  26 . This bidirectional communication allows information to be transmitted from central access controller  24  to central wireless communicator  26  and/or received by central access controller  24  from central wireless communicator  26 . 
         [0016]    Each remote access control system  22  is configured to communicate wirelessly and bidirectionally with central wireless communicator  26  of central control module  20 , as shown in  FIG. 2  by double-headed arrow  34  interconnecting central wireless communicator  26  and remote access control system  22 . A portion of each remote access control system  22  is mounted within the lock mechanism  18  and includes remote wireless communicator  36 , remote access controller  38 , key reader/user input device  40 . Remote wireless communicator  36  is configured to communicate information wirelessly and bidirectionally to and from central wireless communicator  26 . Remote access controller  38  is configured to communicate bidirectionally with remote wireless communicator  36  as indicated by double-headed arrow  42 . Therefore, remote access controller  38  can send or receive information to or from central access controller  24  through remote and central wireless communicators  36  and  26 . This allows remote access controller  38  to send user access information to central access controller  24  while also allowing central access controller  24  to change the programming of remote access controller  38  by, for instance, determining which keys  16  have access to which doors  14 . 
         [0017]    Key reader  40  is configured to read data stored on key  16  and transmit the data to remote access controller  38 . If the data from key  16  are determined by remote access controller  38  to be valid, remote access controller  38  will send an “unlock” signal to lock mechanism  18  mounted to door  14 . With lock mechanism  18  in an unlocked state, user  12  is able to open door  14 . Key reader  40  can be a card reader as shown in  FIG. 1 , or it can be any other device which interprets key data to permit an authorized user to access a controlled door. A few examples of what key reader  40  may be are: a keypad, a fingerprint reader, and a voice recognition device. In those cases, key  16  would respectively be: the code of numbers user  12  punches into the keypad, the fingerprint of user  12 , and the voice of user  12 . 
         [0018]      FIG. 3  shows an exploded perspective view of lock mechanism  18  which is mounted to door  14  ( FIG. 1 ). Remote access control system  22  is positioned within lock mechanism  18  to control the locking and unlocking of lock mechanism  18 . Remote access control system  22  includes remote access controller  38 , key reader  40 , housing  44 , first plate  46 , second plate  48 , handles  50  and  50 ′, impedance matching network  52 , and transmitter/receiver or transceiver circuit  54 . Housing  44  has first plate  46  and second plate  48  that come together to be mounted on door  14 . First plate  46  can act as a radiating device and mounts remote access controller  38 , impedance matching network  52 , and transceiver circuit  54  to door  14 . Second plate  48  mounts key reader  40  to door  14 . Each plate also mounts handle  50  and  50 ′ to door  14 . 
         [0019]    When first and second plate  46  and  48  come together to form housing  44 , holes  56  and  58  accommodate lock mechanism  18 , which is mounted to door  14  and is used to latch and lock door  14 . Lock mechanism  18  includes handles  50  and  50 ′, latch retractor assembly  60 , latch  62 , deadbolt actuator  64 , deadbolt  66 , and spindle  68 . Lock mechanism  18  is operated by actuating either of the handles  50  and  50 ′ in order to rotate latch retractor assembly  60  which is connected to latch  62 . Latch retractor assembly  60  is electrically connected to remote access controller  38  through wire  70  so that control signals from remote access controller  38  can be sent to latch retractor assembly  60  to move latch retractor assembly  60  back and forth from an unlocked to a locked state. In the unlocked state, latch retractor assembly  60  can be operated by either handle  50  and  50 ′ to retract latch  62  from its extended position (shown in  FIG. 3 ) engaging a door frame to its retracted position (not shown) inside door  14  and disengaging the door frame. Lock mechanism  18  also may include deadbolt actuator  64  and deadbolt  66 . Deadbolt actuator  64  is electrically connected to remote access controller  38  through wire  72 , so that control signals from remote access controller  38  can be sent to deadbolt actuator  64  to move deadbolt actuator  64  back and forth between an unlocked and a locked state. In the unlocked state, deadbolt actuator  64  is rotated or manipulated such that deadbolt  66  is in a retracted position (shown in  FIG. 3 ) disengaging the door frame. In the locked state, deadbolt actuator  64  is rotated or manipulated such that deadbolt  66  is in an extended position and engages the door frame so that door  14  cannot be accessed, regardless of whether latch retractor assembly  60  is in an unlocked or locked state. Although the two forms of locks on lock mechanism  18  are mortise and deadbolt, lock mechanism  18  can include any type of lock that is suitable to secure door  14 . 
         [0020]    Spindle  68  is configured to extend through latch retractor assembly  60  and connect handles  50  and  50 ′ together. When latch retractor assembly  60  is in the unlocked state, rotation of either handle  50  and  50 ′ rotates spindle  68  which then rotates latch retractor assembly  60  to move latch  62  into its retracted position. 
         [0021]    Handles  50  and  50 ′ form an external portion of lock mechanism  18  and can be used mechanically to operate lock mechanism  18  between the unlocked state and the locked state. However, one or both handles  50  and  50 ′ are also used electrically as antennas. Handles  50  and  50 ′ are typically fashioned out of metals or other material that acts as a conductive element and has low resistance. Handles  50  and  50 ′ such as shown in  FIG. 3  also have an appreciable length and have a distinctive “L” shape, which extends them away from the remainder of lock mechanism  18  and door  14  into free space. Other types and shapes of door handles can also be used as antennas. It has been found that handles  50  and/or  50 ′ are quite conductive and are of sufficient length to radiate efficiently in the 400 MHz, 900 MHz, and 2 GHz bands. Ideally the length of handles  50  and/or  50 ′ is equal to or above a quarter of the wavelength of a lowest frequency band selected for system  10 . In other embodiments, the handles  50  and  50 ′ can be adapted to radiate effectively in many other bands, for example, between the 300 MHz to 10 GHz bands. 
         [0022]    In order for handles  50  and  50 ′ to have the dual purpose of mechanically operating door  14  and electrically operating as antennas, they should be electrically isolated from the rest of the metal that may be present in housing  44  and door  14 , for best efficiency.  FIG. 3  shows three possible spots on each handle  50  and  50 ′ that could be used for electrical isolation. A typical way to “break” the electrical connection is to add one or two of three insulating pieces  74 ,  76 , and  78  to handles  50  and  50 ′. Insulating pieces  74  are in particularly good spots on handles  50  and  50 ′, because they are closest to door  14  and that allows handles  50  and  50 ′ to have a longer effective antenna length. Insulating pieces  74 ,  76 , and  78  may be made out of a strong polymer such as nylon or Delrin®, or any other strong fire retardant polymer. In  FIG. 3 , insulating piece  74  has spindle hole  80  to accommodate spindle  68 . In this case, spindle  68  should also be made out of a material that does not electrically conduct between handles  50  and  50 ′. There are other ways to connect handles  50  and  50 ′ and isolate them electrically; several more examples can be seen in  FIGS. 4A and 4B . 
         [0023]    The use of one or both handles  50  and  50 ′ as antennas for remote access control system  22  using radio frequency (RF) signals leads to an increase in robustness and communication range of door security system  10  while maintaining the aesthetics of door  14 . This increase in robustness and communication range is due to the antenna(s) forming an externally exposed portion of the lock mechanism  18  (i.e. the antenna is not housed within the lock mechanism  18  or a cavity of door  14  either of which can act as a barrier to efficient EM radiation). The increase in communication range means that fewer repeaters  30  need to be used. 
         [0024]    Using both handles  50  and  50 ′ also can greatly reduce the effects of multipath. Multipath is a phenomenon where radio signals reach a receiving antenna by two or more paths. The undesirable effects of multipath include destructive interference, causing phase cancelation and/or reduction of the radio signal. Because both handles  50  and  50 ′ are able to act as antennas, a radio signal is not limited to one antenna mounted on door  14 ; the two antennas inches away from one another can switch receiving duties or operate simultaneously to reduce any multipath effects. 
         [0025]    Insulating piece  74  also has wire hole  82  so that wires  84  can electrically connect handles  50  and  50 ′ to impedance matching network  52 ; wires  84  can go through any hole in door  14  that is suitable to reach impedance matching network  52 , such as holes  56 ,  58 , and  86 . Impedance matching network  52  is then electrically connected by wire  88  to transceiver circuit  54 , which is electrically connected to remote access controller  38  by wire  90 . As is well known in the art, impedance matching network  52  operates to adjust the load (antenna) impedance relative to the source (transceiver) impedance such that the load (antenna) impedance is matched to the source (transceiver) impedance (i.e. in a low-frequency or DC system the resistance if the load is equal to the resistance of the source). In this manner, the maximum possible power is transferred from the transceiver to the antenna and from the antenna to the transceiver in the case of receiving. 
         [0026]    Further shown in  FIG. 3  is wire  92  extending through hole  86  and electrically coupling remote access controller  38  and key reader  40 . Transceiver  54  is used to communicate (i.e. transmit and receive) information between remote access controller  38  and central wireless communicator  26  through handles  50  and  50 ′ acting as antennas. Transceiver  54  includes transmitter  94  and receiver  96 . Remote access controller  38  can transmit information through transmitter  94  and handles  50  and  50 ′ to central wireless communicator  26 . Conversely, wireless information transmitted by central access controller  24  through central wireless communicator  26  can be received by remote access controller  38  through handles  50  and  50 ′ and receiver  96 . Battery  97  may be added to power remote access controller  38 , deadbolt actuator  64 , and key reader  40 . 
         [0027]      FIG. 4A  shows another way of isolating handle  50  and  50 ′ electrically from the other metal of the lock mechanism  18  and remote access control system  22 . Insulating sleeve  98  includes spindle cavity  100  that is configured to receive spindle  68 . Handle  50  and  50 ′ includes insulating sleeve cavity  102  that is configured to receive insulating sleeve  98 . Insulating sleeve  98  still includes wire hole  82  so that handle  50  and  50 ′ can communicate electrically as an antenna with remote access controller  38 . Insulating sleeve  98  also forms a capacitor which can be used as part of an impedance matching network to the antenna/handle. 
         [0028]      FIG. 4B  is yet another way of isolating handle  50  and  50 ′ electrically from the other metal components in remote access control system  22  and lock mechanism  18 . Handle  50  and  50 ′ includes rectangular openings  104  in its metal exterior thus forming an inductive connection “electrically” isolating first handle piece  106  and second handle piece  108  at the wavelength of choice. Again, rectangular openings  104  form an inductive component which in part can be part of an impedance matching network to the antenna/handle. 
         [0029]      FIG. 5  is another embodiment of remote access control system  22  similar to the one shown in  FIG. 3 . Accordingly, the discussion of how lock mechanism  18  works will be left out. In  FIG. 5 , escutcheons  110  are used to put together housing  44  instead of plates with key reader  40 . Escutcheons  110  extend externally away from door  14  (FIG. 
         [0030]      1 ) and the remainder of lock mechanism  18  into an area of free space and can be circular, oblong, or otherwise any other shape suitable for mounting remote access control system  22  to door  14 . This time, however, escutcheons  110  are used as antennas to communicate with remote access controller  38  instead of handles  50  and  50 ′. Therefore, escutcheons  110  should be electrically isolated from the other metal components of remote access control system  22  for best performance. Insulating sleeves  112  which are fashioned to connect handles  50  and  50 ′ into escutcheons  110  electrically isolate escutcheons  110  while allowing handles  50  and  50 ′ to be mechanically connected to lock mechanism  18  and allowing handles  50  and  50 ′ to access door  14 . 
         [0031]    In both embodiments in  FIG. 3  and  FIG. 5 , it is important to note that many security systems that either would like to utilize wireless technology in the future or already do use wireless technology would benefit from the aesthetic appeal of using existing metal structures such as the handles and escutcheons as the antenna(s) for wireless communication. These existing metal structures have an appreciable mass and length that are suitable for use as antennas; they also are external to the door and form an external portion of the lock mechanism which projects away from the door into free space, improving effectiveness as an antenna consequently reducing the need for repeaters. 
         [0032]    Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.