Patent Publication Number: US-2023141216-A1

Title: Electromechanical locks and related methods

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a continuation of PCT Application Serial No. PCT/US2021/043470, filed Jul. 28, 2021 which claims the priority of U.S. Provisional Patent Application Ser. No. 63/057,362 filed on Jul. 28, 2020, the disclosures of which are incorporated herein by reference in their entirety. 
    
    
     TECHNICAL FIELD 
     Embodiments relate generally to locks, and, more specifically, to high-security electromechanical combination locks for use in connection with safes and other secured containers, enclosures, and any other security components. Embodiments also relate to methods involving such locks. 
     BACKGROUND 
     Enclosures, which may be rooms, safes, cabinets and the like, are used to securely store highly valuable and highly sensitive items. In some circumstances, it may be advisable to utilize high-security locks, such as high-security electromechanical combination locks, on such securable enclosures. Typically, for example, a high-security electromechanical lock would be used on a door or other access component of the enclosure. Some high-security electromechanical combination locks may be configured for operation independent of externally supplied electrical power. 
     Some known high-security electromechanical locks relying primarily on batteries as a source of electrical power may require frequent battery replacement. High-security electromechanical locks may utilize integral, self-generating electrical power sources, such as electrical generators driven by rotation of a combination dial. Self-generating locks may require substantial angular rotation of the combination dial to generate sufficient electrical power. For example, this may be well beyond the rotation necessary to enter the combination. 
     It would be desirable to provide additional advancements related to high-security electromechanical combination locks, particularly for such locks that include electrical generators. 
     SUMMARY 
     Generally, a dial ring assembly for an electromechanical combination lock is provided and includes a housing configured to be mounted on an exterior of a securable enclosure, a dial rotatably disposed on the housing, the dial being rotatable about a dial axis for use in connection with entry of a combination, a lever rotatably disposed on the housing, the lever being rotatable about a lever axis, an external generator disposed in the housing, the external generator being configured to generate electrical energy through rotation of an external generator shaft of the external generator, and a gear train disposed in the housing and operatively connecting the dial, the lever, and the external generator shaft. Rotation of the dial may rotate the external generator shaft to produce electrical energy. Rotation of the lever may rotate the external generator shaft to produce electrical energy. Rotation of the lever may rotate the dial and the external generator shaft. 
     In some embodiments the gear train may comprise a dial drive gear operatively connected to the dial for rotation with the dial, and an external generator shaft driven gear operatively connected to the external generator shaft for rotation with the external generator shaft. The gear train may comprise a first intermediate gear coupled to rotate coaxially with a second intermediate gear, the first intermediate gear engaging the dial drive gear and the second intermediate gear engaging the external generator shaft driven gear. 
     In alternative or additional aspects, the gear train may comprise a lever drive gear operatively connected to the lever for rotation with the lever, and a lever driven gear operatively connected to the dial drive gear for rotation with the dial drive gear. The gear train may comprise a lever idler gear interposing the lever drive gear and the lever driven gear. The lever drive gear may include an internal gear segment. The lever may be rotatable about the lever axis between a first angular position, a second angular position, and a third angular position. In the first angular position, the lever drive gear may be disengaged from the dial drive gear. In the second angular position, the third angular position, and between the second angular position and the third angular position, the lever drive gear may be operatively connected to the dial drive gear such that rotation of the lever between the second angular position and the third angular position rotates the external generator shaft. In some embodiments, rotation of the lever between the first angular position and the second angular position may not rotate the external generator shaft. The gear train may comprise a lever idler gear operatively interposing the lever drive gear and the lever driven gear and in the first angular position, the internal gear segment of the lever drive gear may be angularly separated from the lever idler gear such that the lever drive gear is disengaged from the dial drive gear. 
     In some embodiments, the dial ring assembly may further comprise a rotatable spindle configured to be operatively connected to a lock assembly mounted on an interior of the securable enclosure and the spindle may be coupled to the lever for rotation with the lever. The spindle may be positioned coaxially with the lever axis and may be rotatable about the lever axis. Rotation of the lever and the spindle may be selectively operative to extend and retract a bolt and when the bolt is in an extended position, the securable enclosure is in a secured condition. The lever may be movable between a first position in which the bolt is extended and a second position in which the bolt is retracted, and the position of the lever may be visually indicative of the status of the securable enclosure being secured or unsecured. 
     In alternative or additional aspects, the dial ring assembly may further comprise an electronic display disposed on the housing, the electronic display may be configured to display at least one indicium associated with entry of the combination. The display may include audible or other perceptible indicum associated with entry of the combination. The display may be substantially planar. The display may be oriented substantially transversely to the dial axis. The display may be oriented substantially parallel to the dial axis. The display may be repositionable between at least two angular display orientations relative to the dial axis. 
     In some embodiments, the dial ring assembly may include at least one of a transmitter and a receiver configured for communication with a remote station. The at least one of the transmitter and the receiver may be configured to communicate wirelessly with a communication unit. The communication unit may be operatively connected to the remote station. The transmitter may comprise an infrared transmitter and the receiver may comprise an infrared receiver. The transmitter may be configured to transmit data associated with at least one of a locking event, an unlocking event, and a status report. 
     In alternative or additional aspects, the dial ring assembly may further comprise a photovoltaic array configured to produce electrical energy. The photovoltaic array may be disposed at least partially circumferentially on the housing. The photovoltaic array may be disposed at least partially circumferentially around the dial. 
     In alternative embodiments, the dial may be axially displaceable along the dial axis. The dial may be biased axially outward. The dial may be configured such that pressing the dial axially inward actuates at least one switch. In some embodiments, the dial ring assembly may further comprise a switch disposed on the housing. 
     In some embodiments, the dial ring assembly may further comprise an external processor disposed in the housing. The external processor may be configured to monitor rotation of the dial. The external processor may be configured to communicate with an internal processor disposed within an interior of the securable enclosure. The external processor may be configured to communicate with the internal processor using encrypted infrared data. 
     In some embodiments, an electromechanical combination lock, may comprise the dial ring assembly and a lock assembly comprising a bolt, the bolt being selectively extendable and retractable. A securable enclosure may comprise a plurality of walls at least partially defining an interior, an access component arranged to selectively close an opening though the plurality of walls, and the electromechanical combination lock disposed on one of the door or one of the plurality of walls. The electromechanical combination lock may be configured to secure the door in a closed position. 
     Generally, a method of manufacturing a security device is provided, the method comprising assembling a dial ring assembly, comprising providing a housing configured to be mounted on an exterior of a securable enclosure, disposing an external generator in the housing, the external generator being configured to generate electrical energy through rotation of an external generator shaft of the external generator, rotatably disposing a dial on the housing, the dial being rotatable around a dial axis, rotatably disposing a lever on the housing, the lever being rotatable about a lever axis, and disposing a gear train in the housing, the gear train operatively connecting the dial, the lever, and the external generator shaft such that rotation of the dial rotates the external generator shaft to produce electrical energy and rotation of the lever rotates the external generator shaft to produce electrical energy, the dial being rotatable for use in connection with entry of a combination. 
     The method of manufacture may further comprise disposing an electronic display on the housing, the electronic display being configured to display at least one indicium associated with entry of a combination. The method may further comprise disposing a photovoltaic array on the dial ring assembly. Disposing the photovoltaic array on the dial ring assembly may comprise disposing the photovoltaic array at least partially circumferentially around the housing. Disposing the photovoltaic array on the dial ring assembly may comprise disposing the photovoltaic array at least partially circumferentially around the dial. The method may further comprise installing the dial ring assembly on an exterior of one of a wall and a door of a securable enclosure and installing a lock assembly on an interior of the one of the wall and the door, including operatively connecting the dial ring assembly and the lock assembly through the one of the wall and the door. The method of manufacture may further comprise installing a photovoltaic array on the securable enclosure, including operatively connecting the photovoltaic array to the dial ring assembly, the photovoltaic array comprising a photovoltaic panel. 
     A method of operating an electromechanical combination lock is provided, the method may comprise entering a combination by rotating a dial disposed on a dial ring assembly about a dial axis. Rotating the dial may produce electrical energy by rotating an external generator shaft of an external generator disposed in a housing of the dial ring assembly. Retracting a bolt extending from a lock assembly may be accomplished by rotating a lever disposed on the dial ring assembly about a lever axis, the lock assembly being operatively connected to the dial ring assembly and rotating the lever may produce electrical energy by rotating the external generator shaft. Entering the combination may include viewing at least one indicium associated with the combination on an electronic display disposed on the housing. Entering the combination may comprise axially displacing the dial along the dial axis in a single press to actuate at least one switch. Entering the combination may comprise axially displacing the dial along the dial axis in a double press to change between at least two modes. Alternatively, entering the combination may comprise actuating a switch located on the housing to change between at least two modes. Entering the combination may comprise viewing one of a random alphabetic character, a random numeric character, and a random symbol, and selecting one of an alphabetic mode, a numeric mode, and a symbol mode, and entering a combination element. The electronic display may display at least one indicium associated with entry of the combination. The display may present audible or other perceptible indicum associated with entry of the combination. Retracting the bolt may comprise rotating the lever in a first direction. The method may further comprise extending the bolt by rotating the lever in a second direction, the second direction being opposite of the first direction. 
     In some embodiments, a dial ring assembly for an electromechanical combination lock may comprise a housing configured to be mounted on an exterior of a securable enclosure, a dial rotatably disposed on the housing, the dial being rotatable about a dial axis for use in connection with entry of a combination, and an electronic display disposed on the housing, the electronic display being configured to display at least one indicium associated with entry of the combination. The display may be repositionable between at least two angular display orientations relative to the dial axis. The display may be pivotable between the at least two angular display orientations. The at least two angular display orientations may be discrete, fixed angular display orientations and the display may be selectively installable in each of the at least two discrete, fixed angular display orientations. The at least two angular display orientations may comprise a first angular display orientation substantially transverse to the dial axis and a second angular display orientation substantially parallel to the dial axis. The dial ring assembly may further comprise a lever rotatably disposed on the housing, the lever being rotatable about a lever axis, an external generator disposed in the housing, the external generator being configured to generate electrical energy through rotation of an external generator shaft of the external generator, and a gear train operatively connecting the dial, the lever, and the external generator shaft such that rotation of the dial rotates the external generator shaft to produce electrical energy and rotation of the lever rotates the external generator shaft to produce electrical energy. The lever may be rotatable about the lever axis between a first angular position, a second angular position, and a third angular position. In the first angular position, the lever may be disengaged from the external generator shaft. In the second angular position, in the third angular position, and between the second angular position and the third angular position, the lever may be operatively connected to the external generator shaft such that rotation of the lever between the second angular position and the third angular position rotates the external generator shaft. The electromechanical combination lock may further comprise a lock assembly comprising a bolt, the bolt being selectively extendable and retractable. 
     A securable enclosure may comprise a plurality of walls at least partially defining an interior, a door arranged to selectively close an opening though the plurality of walls, and an electromechanical combination lock disposed on one of the door and one of the plurality of walls. The electromechanical combination lock may be configured to secure the door in a closed position. 
     A method of reconfiguring an electromechanical combination lock is provided, the method comprising repositioning an electronic display of a dial ring assembly of an electromechanical lock from a first angular display orientation to a different, second angular display orientation relative to a dial axis, the dial ring assembly comprising a housing configured to be mounted on an exterior of a securable enclosure, the dial ring assembly including a dial disposed on the housing, the dial being rotatable about the dial axis for use in connection with entry of a combination, the display being configured to display at least one indicium associated with entry of the combination. Repositioning the electronic display may include pivoting the display from the first angular display orientation to the second angular display orientation. Repositioning the electronic display may comprise pivoting the display from the first angular display orientation to the second angular display orientation while the electromechanical lock is mounted on the securable enclosure. Each of the first angular display orientation and the second angular display orientation may be a discrete, fixed angular display orientation. The display may be selectively installable in each of the first angular display orientation and the second angular display orientation. Repositioning the electronic display may comprise removing the display from the first angular display orientation and installing the display in the second angular display orientation. Each of the first angular display orientation and the second angular display orientation may be one of substantially transverse to the dial axis and substantially parallel to the dial axis. 
     A method of installing an electromechanical combination lock on a securable enclosure may comprise mounting a dial ring assembly on an exterior of one of a wall and a door of a securable enclosure, the dial ring assembly comprising a housing, a dial rotatably disposed on the housing, the dial being rotatable about a dial axis for use in connection with entry of a combination, a lever rotatably disposed on the housing, the lever being rotatable about a lever axis, an external generator disposed in the housing, the external generator being configured to generate electrical energy through rotation of an external generator shaft of the external generator, and a gear train operatively connecting the dial, the lever, and the external generator shaft such that rotation of the dial rotates the external generator shaft to produce electrical energy and rotation of the lever rotates the external generator shaft to produce electrical energy. The method may further comprise mounting a lock assembly on an interior of one of the wall and the door, including operatively connecting the dial ring assembly and the lock assembly through one of the wall and the door. Operatively connecting the dial ring assembly and the lock assembly may comprise connecting a rotatable spindle to the dial ring assembly and the lock assembly. Operatively connecting the dial ring assembly and the lock assembly may include installing a power tube comprising at least one conductor electrically connecting the dial ring assembly and the lock assembly. The method may further comprise installing a photovoltaic array on the securable enclosure, including operatively connecting the photovoltaic array to the dial ring assembly, the photovoltaic array comprising a photovoltaic panel. 
     Additional aspects and advantages of the invention will become more apparent upon further review of the detailed description of the illustrative embodiments taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is an isometric view of an illustrative securable enclosure including an illustrative electromechanical combination lock. 
         FIG.  2    is an isometric view of an illustrative dial ring assembly. 
         FIG.  3    is a rear isometric exploded view of an illustrative electromechanical combination lock. 
         FIG.  4    is an exploded, rear isometric view of the dial ring assembly of  FIG.  2   . 
         FIG.  5    is an exploded isometric view of the dial of  FIG.  2    and an illustrative dial switch assembly. 
         FIG.  6    is a front isometric view of a portion of an illustrative gear train disposed in the housing of the dial ring assembly of  FIG.  2   . 
         FIG.  7    is a side isometric view of a portion of the illustrative gear train of  FIG.  6   . 
         FIG.  8    is a rear isometric view of a portion of the illustrative gear train of  FIGS.  6  and  7   . 
         FIG.  9    is a partial front elevation view of a lever drive gear in a rotational position with respect to a lever idler gear. 
         FIG.  10    is a partial front elevation view of the lever drive gear of  FIG.  9    in an alternate rotational position with respect to the lever idler gear. 
         FIG.  11    is a partial front elevation view of the lever drive gear of  FIGS.  9  and  10    in an alternate rotational position with respect to the lever idler gear. 
         FIG.  12    is a simplified schematic diagram showing an illustrative electrical arrangement for an electromechanical lock. 
         FIG.  13    is an isometric view of an alternative illustrative dial ring assembly. 
     
    
    
     DETAILED DESCRIPTION 
     Illustrative embodiments according to at least some aspects of the present disclosure are described and illustrated below and include devices and methods relating to security devices including locks, such as electromechanical combination locks, and securable enclosures utilizing such locks. It will be apparent to those of ordinary skill in the art that the embodiments discussed below are illustrative examples and may be reconfigured without departing from the scope and spirit of the present disclosure. It is also to be understood that variations of the exemplary embodiments contemplated by one of ordinary skill in the art shall concurrently comprise part of the instant disclosure. The illustrative embodiments as discussed below may include optional steps, methods, and features that one of ordinary skill should recognize as not being a requisite to fall within the scope of the present disclosure. 
     The present disclosure includes, inter alia, security devices including high-security electromechanical combination locks for use on securable enclosures, and related methods. Some illustrative embodiments according to at least some aspects of the present disclosure relate to security devices, including securable enclosures such as safes, filing cabinets, security containers, vaults, secure rooms, and the like. 
       FIG.  1    is an isometric view of an illustrative securable enclosure  10  including an illustrative electromechanical combination lock  100 , according to at least some aspects of the present disclosure. The illustrative securable enclosure  10  is generally in the form of a safe configured to securely contain highly valuable and/or highly sensitive articles therein and includes an interior  12 , which is at least partially defined by a plurality of walls  22 . The interior  12  of the enclosure  10  is selectively accessible from an exterior  14  of the enclosure  10 , such as via a repositionable (e.g., hinged) door  16  operatively arranged to selectively close an opening  22   a  in the walls  22 . 
     In this illustrative embodiment, the lock  100  is mounted to the door  16  and includes a selectively extendable and retractable bolt  102 , which is configured to secure the door  16  in a closed position. The illustrative lock  100  includes a dial ring assembly  200  disposed on the exterior  18  of the door  16  and a lock assembly  300  disposed on the interior  20  of the door  16 . Generally, the lock assembly  300  may include various structures and features, such as the bolt  102 , as may be necessary to perform the functions of the lock assembly  300  as described herein. 
     In alternative embodiments, the securable enclosure  10  may be in the form of another type of security device or container (e.g., a filing cabinet) or may be in the form of a larger secure area, such as a vault or a secure room. In some embodiments, the lock  100  may be mounted on the securable enclosure  10  (e.g., on a wall  22 ) proximate the door  16 , rather than on the door  16 . In some embodiments, the bolt  102  of the lock  100  may act directly to secure the door  16  in the closed position, or the bolt  102  may act in connection with a mechanism, such as boltworks, to secure the door  16  in the closed position. 
       FIG.  2    is an isometric view of the illustrative dial ring assembly  200 ,  FIG.  3    is a rear isometric exploded view of the illustrative lock  100 , and  FIG.  4    is an exploded, rear isometric view of the illustrative dial ring assembly  200 , all according to at least some aspects of the present disclosure. 
     Referring to  FIGS.  1 - 4   , the illustrative dial ring assembly  200  includes a housing  202  configured to be mounted on the exterior  18  of the enclosure  10 . A combination entry component, such as a rotatable dial  204 , is rotatably disposed on the housing  202 . The dial  204  is rotatable about a dial axis  206 , such as for use in connection with the entry of a combination by a user. In some embodiments, the dial  204  may be easily rotatable by a user&#39;s finger tips to facilitate ease of dialing. For example, the dial torque may be about 16 to 20 inch-ounces (0.113 to 0.141 N-m). The dial axis  206  may be generally perpendicular to the generally flat exterior  18  of the enclosure  10 . The housing  202  may comprise a first, outer portion  202   a  receiving the dial  204  and a second, inner portion  202   b,  which is disposed against the exterior  18  of the enclosure  10 . 
     In this illustrative embodiment, a switch  205  is mounted to the housing  202  and oriented that such that the switch  205  may be operated by a user&#39;s thumb and/or finger in conjunction with the user operating the dial  204 , for example. The switch  205  may be a push button, for example. The switch  205  may be radially displaceable inward toward the center of the dial  204 . The switch  205  may be biased radially outward away from the center of the dial  204 . Pressing the switch  205  radially inward toward the center of the dial  204  may actuate the switch  205  and be operative to enter an element of a combination, toggle between modes (e.g., between alphabetic characters, numeric characters, and/or any other symbols or characters of any type), and/or otherwise facilitate communication between the user and the lock  100 . For example, a single press of the switch  205  may be used to enter an input (e.g., a selected element of a combination or a selection from a menu) and/or a double press may be used to change modes as described further below, for example, in connection with changing the type of character being input (e.g., alphabetic, numeric, symbol, etc.). 
       FIG.  5    is an exploded isometric view of the dial  204  and an illustrative dial switch assembly  220 , according to at least some aspects of the present disclosure. Referring to  FIGS.  1 - 5   , in the illustrative dial ring assembly  200 , the dial  204  is mounted to the housing  202  such that the dial  204  is axially displaceable (e.g., along the dial axis  206 ) inward toward the housing  202 . The dial  204  may be biased (e.g., by a spring or wave washer, or by magnets arranged to repel one another) axially outward away from the enclosure  10 . Pressing the dial  204  axially inward in the direction of the enclosure  10  may actuate one or more switches  222   a,    222   b,    222   c,    222   d  disposed on the dial switch assembly  220 . Actuation of the one or more switches  222   a,    222   b,    222   c,    222   d  may be operative to enter an element of a combination, toggle between modes (e.g., between alphabetic characters, numeric characters, symbols and/or characters of any type), and/or otherwise facilitate communication between the user and the lock  100 . For example, a single press of the dial  204  may be used to enter an input (e.g., a selected element of a combination or a selection from a menu) and/or a double press may be used to change modes. 
     Referring again to  FIGS.  1 - 4   , the illustrative dial ring assembly  200  includes a lever  208  that is rotatably disposed on the housing  202 . The lever  208  is rotatable about a lever axis  210 , which may be substantially parallel to, such as coaxial with, the dial axis  206 . The lever  208  may include one or more features configured to be grasped by a user, such as a knob  212 . As described below, the lever  208  is rotatable to generate electrical power and/or, selectively, to retract and/or extend the bolt  102 . 
     The illustrative dial ring assembly  200  includes a display, such as an electronic display  214 , disposed on the housing  200  for viewing by a user. In some example embodiments, the electronic display may comprise a dot matrix display. The display  214  may comprise an organic light-emitting diode (“OLED”) display and/or an E Ink (“electronic ink”) display, for example. The electronic display  214  is configured to display one or more indicia  216  associated with operation of the lock  100 , such as one or more alphabetic characters  216   a,  one or more numeric characters  216   b,  and/or one or more symbols  216   c . The indicia  216  may be used in connection with entering a combination and/or changing a combination, for example. The display  214  is substantially planar and is oriented substantially transversely to the dial axis  206  (e.g., at about 45 degrees). As used herein, “transverse” may refer to relative angular orientations that are non-parallel (e.g., perpendicular or oblique). In alternative embodiments, the display  214  may be mounted in other orientations or positions. 
     Alternative embodiments may include a display  214  that is repositionable between at least two angular display orientations with respect to the dial axis  206 . For example, the display  214  may be pivotable between at least two angular display orientations. In other exemplary embodiments, the display  214  may be selectively installable in each of at least two discrete, fixed angular display orientations. The at least two angular display orientations may include a first angular display orientation substantially transverse to the dial axis and a second angular display orientation substantially parallel to the dial axis. 
     Illustrative methods involving repositioning displays, such as methods of reconfiguring a lock  100 , are described. A method may include repositioning the display  214  from a first angular display orientation to a different, second angular display orientation. For example, repositioning the display  214  may include pivoting the display  214 , such as while the lock  100  is mounted on a securable enclosure  10 . Where the angular display orientations are discrete, fixed orientations, the method may include removing the display  214  from the first angular display orientation and installing the display  214  in the second angular display orientation. 
     The illustrative dial ring assembly  200  includes a dial ring photovoltaic array  218  disposed circumferentially on the exterior of the housing  200 . The dial ring photovoltaic array  218  produces electrical energy for the lock  100  using light incident on the lock  100 . 
     Referring to  FIGS.  1 - 3   , the lock  100  may include one or more connections, such as mechanical connections, electrical connections, data connections, etc., between the exterior dial ring assembly  200  and the internal lock assembly  300 , such as through the door  16  or wall  22  of the enclosure  10 . The illustrative lock  100  includes a rotatable spindle  224 , which is configured to extend from the dial ring assembly  200  to the lock assembly  300 . The lever  208  is mechanically coupled to the spindle  224  such that rotating the lever  208  rotates the spindle  224 . In this illustrative embodiment, the spindle  224  is positioned coaxially with the lever axis  210  and is rotatable about the lever axis  210 . The lock assembly  300  is configured so that, under certain conditions, rotation of the spindle  224  by the lever  208  is operative to retract and/or extend the bolt  102  of the lock assembly  300 , as described below. 
     Referring to  FIGS.  1  and  3   , in this illustrative embodiment, one or more electrical conductors  226  extend between the dial ring assembly  200  and the lock assembly  300 . The conductors  226  are disposed on the radially outer surface of a generally cylindrical power tube  228 . The power tube  228  is substantially hollow and receives the rotatable spindle  224  therethrough. The power tube  228  may be housed radially within an outer tube  230 . Any other suitable manner of conducting electrical power and/or signals may be used instead of, or in addition, to the power tube  228 . 
     The illustrative dial ring assembly  200  includes an external processor  232  disposed in the housing  202 , which is configured to communicate with an internal processor  234  disposed within the interior of the enclosure  10 , such as in the lock assembly  300 . For example, the external processor  232  and the internal processor  234  may be configured for encrypted infrared data transfer therebetween, such as through the outer tube  230 . In some exemplary embodiments, the processors  232 ,  234  may be synchronized and/or may be matched at the time of manufacture, for example by matching serial numbers. 
     The external processor  232  is configured to perform various functions associated with operation of the lock  100 . For example, the external processor  232  may monitor rotation of the dial  204 , such as directional information from sensors associated with the dial  204  to increment and/or decrement the display electronics. The external processor  232  may control and/or update the information shown on the display  214 . The external processor  232  may control the internal processor  234 , such as via a two-wire tube system and/or an infrared communication system. The external processor  232  may transmit the user dial inputs to the internal processor  234 , which may subsequently detect the combination entry. The external processor  232  may shut down the power to the internal processor  234  and/or the external processor  232 , and/or may signal to shut down the internal power. The external processor  232  may coordinate, such as through the display  214 , combination entry and/or storage for the internal processor  234 . The external processor  232  may control the display of pertinent lock status (e.g., locked and/or unlocked) on the display  214 . The external processor  232  may compute and/or display random initial characters on the display  214  during combination entry. The external processor  232  may impose dialing delays when excessive combination entries have been attempted. The external processor  232  may accept information from the internal processor  234 , such as information indicating that the correct combination was entered. The external processor  232  may maintain pertinent information for encrypting and display for the supervisor coordinator. The external processor  232  may store audit trail information, such as time of entry tries, user opening tries, etc. Other electronics in the dial ring assembly  200  may also perform various functions associated with operation of the lock  100 . For example, some electronics may rectify the phase signals from an electrical power generator (e.g., a three-phase generator). Some electronics may detect operation of various components (e.g., a lever) and/or the position of such components. Some electronics may sense additional operation of various components (e.g., a lever). Some electronics may facilitate transmission and/or receipt of information, such as via infrared or RF communication. Some electronics may sense the rotational direction and/or position of the dial  204  and/or other components (e.g., a generator). Some electronics may perform connecting and/or clamping functions for various signals, such as photovoltaic cell power lines. Some electronic components may house various components, such as photovoltaic cells, a real-time clock, a battery for a real-time clock, and/or display electronics. Some electronics may monitor and/or control start-up power conditions. 
     The internal processor  234  is configured to perform various functions associated with operation of the lock  100 . For example, the internal processor  234  may accept combination entries from the external processor  232 . The internal processor  234  may maintain the opening combinations. The internal processor  234  may compare the combination entered to a desired combination. The internal processor  234  may activate motor drive electronics if a correct combination is entered. The internal processor  234  may communicate to external electronics that the entered combination is correct, or has failed. The internal processor  234  may output audit trail information to a supervisor (e.g., with the securable container open). The internal processor  234  may input biometric or card information to enable lock operation (this may also be implemented from the dial ring). Generally, the internal processor  234  may operate as a secondary element in a primary/secondary relationship with the external processor  232 . Other electronics in the lock assembly  300  may also perform various other functions associated with operation of the lock  100 . Some electronics may facilitate communication between the internal processor  234  and the external processor  232 . Some electronics may comprise motor drive electronics configured to facilitate operation of a motor arranged to engage the mechanism to retract and/or extend the bolt  102 . Some electronics may facilitate start up and/or shut down of various other electronics. Some electronics may be associated with electrical power storage (e.g., capacitors) providing electrical power for various other components. Some electronics may facilitate combination entry and/or audit trail detection initiation and/or communication. 
     In some exemplary embodiments, the lock assembly  300  may include an internal electrical generator  236 . The internal electrical generator  236  may be configured for rotation by the spindle  224  so that the internal electrical generator  236  produces electrical energy when the lever  208  is rotated. Some exemplary embodiments including both an internal electrical generator  236  and an external electrical generator  404  (described below with reference to  FIGS.  6 - 8   ) may not require electrical conductors configured to conduct electrical power between the dial ring assembly  200  and the lock assembly  300  as each assembly  200 ,  300  comprises a respective generator  236 ,  404 . Exemplary embodiments including an internal electrical generator  236  and an external electrical generator  404  may include electrical power storage devices (e.g., power storage capacitors) in both the dial ring assembly  200  and the lock assembly  300 . 
       FIG.  6    is a front isometric view of a portion of an illustrative gear train  400  disposed in the housing  202  of the dial ring assembly  200 ,  FIG.  7    is a side isometric view of a portion of the illustrative gear train  400 , and  FIG.  8    is a rear isometric view of a portion of the illustrative gear train  400 , all according to at least some aspects of the present disclosure. Referring to  FIGS.  2  and  6 - 8   , the illustrative gear train  400  is configured to rotate an external generator shaft  402  of an external electrical generator  404  disposed in the housing  202  to produce electrical energy when the dial  204  and/or the lever  208  are rotated about their respective axes  206 ,  210 . Additionally, in some exemplary embodiments, the external electrical generator  404  may be utilized in connection with detecting rotation of the dial  204 , such as for detecting rotation of the dial  204  in connection with a user entering a combination. For example, the electrical signal from the poles the generator  404  may be used, or a position sensing device, an encoder for example, may be integrated with the generator to provide an electrical signal corresponding to the rotation of the dial  204  by the user. 
     The illustrative gear train  400  comprises a dial drive gear  406  that is operatively connected to the dial  204  for rotation with the dial  204 . In this embodiment, the dial drive gear  406  is coupled for rotation with a hub  408 , which is coupled for rotation with the dial  204 . For example, the dial drive gear  406  may comprise a spur gear that is integrally formed with the hub  408  or a spur gear that is affixed to the hub  408  for rotation with the hub  408 . The illustrative gear train  400  comprises an external generator shaft driven gear  410 , such as a spur gear, which is operatively connected to the external generator shaft  402  for rotation with the external generator shaft  402 . 
     The illustrative gear train  400  comprises a pair of coupled gears interposing the dial drive gear  406  and the external generator shaft driven gear  410 : a first intermediate gear  412  and a second intermediate gear  414 , which are coupled to rotate coaxially together. The first intermediate gear  412  engages and/or is driven by the dial drive gear  406 . The second intermediate gear  414  engages and/or drives the external generator shaft driven gear  410 . In this illustrative gear train  400 , the dial drive gear  406  has a larger diameter than the first intermediate gear  412 , and the second intermediate gear  414  has a larger diameter than the external generator shaft driven gear  410 . Accordingly, the illustrative gear train  400  operates as a double multiplier gear arrangement between the dial  204  and the external generator shaft  402 . In one illustrative embodiment, the gear train  400  provides a gear (e.g., speed) ratio of the dial  204  to the external generator shaft  402  of about 1:13. Thus, rotating the dial  204  about one-half turn rotates the external generator shaft  402  about seven turns. Alternative embodiments may utilize gear trains providing different gear ratios. 
     Referring to  FIGS.  1 - 4  and  6 - 8   , generally, rotation of the dial  204  rotates the dial drive gear  406 , which engages and rotates the first intermediate gear  412 , which is coupled to and rotates the second intermediate gear  414 , which engages and drives the external generator shaft driven gear  410 , which is coupled to and rotates the external generator shaft  402 . Accordingly, rotation of the dial  204  rotates the external generator shaft  402  to produce electrical energy. 
     The illustrative gear train  400  further comprises a gear arrangement configured to cause rotation of the external generator shaft  402  by rotation of the lever  208 . The illustrative gear train  400  comprises a lever drive gear  416  operatively connected to the lever  208  for rotation with the lever  208 . In this exemplary embodiment, the lever drive gear  416  comprises an internal gear segment of about 120 degrees. In some alternative exemplary embodiments, the internal gear segment may be about 140 degrees or at least about 140 degrees. The illustrative gear train  400  comprises a lever driven gear  418 , such as a spur gear, which is operatively connected to the dial drive gear  406  for rotation with the dial drive gear  406 , and a lever idler gear  420 , such as a spur gear, which interposes the lever drive gear  416  and the lever driven gear  418 . 
     Generally, and as described in more detail below, rotation of the lever  208  causes rotation of the lever drive gear  416 , which engages and rotates the lever idler gear  420 , which engages and rotates the lever driven gear  418 , which is coupled to and rotates the dial drive gear  406 . Rotation of the dial drive gear  406  causes rotation of the external generator shaft  402  as described above. Accordingly, rotation of the lever  208  rotates the external generator shaft  402  to produce electrical energy. 
     Additionally, the lever driven gear  418  is coupled to and rotates with the dial drive gear  406 , which is coupled to and rotates with the dial  204 , rotation of the lever  208  causes rotation of the dial  204 . In one illustrative embodiment, the gear train  400  provides a gear (e.g., speed) ratio of the lever  208  to the dial  204  of about 1:3. Thereby, rotating the lever  208  about 120 degrees rotates the dial  204  about 360 degrees. Further, rotating the lever  208  about 120 degrees rotates the external generator shaft  402  about 13 turns. Alternative embodiments may utilize gear trains providing different gear ratios. 
     In the illustrative embodiment, it may be relatively easy for a user to apply torque to the lever  208  that is substantially greater than the maximum dialing toque for the dial  204 . For example, a user may be able to exert about 3-4 times the maximum dialing torque using the lever  208 . Accordingly, in view of the gear ratio of the gear train  400  between the lever  208  and the external generator shaft  402 , rotation of the lever  208  may produce substantially more electrical power than a corresponding rotation of the dial  204 . 
       FIGS.  9 - 11    are partial front elevation views of the lever drive gear  416  in different rotational positions with respect to the lever idler gear  420 , all according to at least some aspects of the present disclosure. Referring to  FIG.  9   , the lever  208  is shown in a first, counter-clockwise-most angular position. The lever  208  may be retained in this first angular position, such as by a magnetic catch  422 . In this first angular position, the lever drive gear  416  (i.e., the internal gear segment) is disengaged from the lever idler gear  420  and, therefore, the dial drive gear  406 . Specifically, in the first angular position, the gear teeth  417  of the lever drive gear  416  are disengaged from the gear teeth  421  of the lever idler gear  420  and the lever drive gear  416  is angularly separated from the idler gear  420 . As described above with reference to  FIGS.  1 - 4  and  6 - 8   , the lever driven gear  418  is coupled to the dial drive gear  406  for rotation with the dial drive gear  406 , and the lever idler gear  420  engages the lever driven gear  418 . Accordingly, rotating the dial  204  also rotates the lever idler gear  420 . But, in the first angular position shown in  FIG.  9   , rotation of the dial  204  does not rotate the lever  208  because the lever drive gear  416  is disengaged from the lever idler gear  420 . 
     Referring to  FIG.  10   , the lever  208  is shown in a second angular position, which is clockwise relative to the first angular position shown in  FIG.  9   . In the second angular position, the lever drive gear  416  has begun to engage the lever idler gear  420 . Specifically, the second angular position is the angular position of the lever  208 , rotating clockwise from the first angular position, at which the lever drive gear  416  initially engages and begins to cause rotation of the lever idler gear  420 . In the illustrative embodiment, the angular difference between the first angular position and the second angular position is about 10 degrees. 
     Because the lever drive gear  416  is disengaged from the lever idler gear  420  when the lever  208  is in the first angular position and when the lever is between the first angular position and the second angular position, rotation of the lever  208  between the first angular position and the second angular position does not cause rotation of the lever idler gear  420  or other components of the gear train  400  ( FIGS.  6 - 8   ). 
     Referring to  FIG.  11   , the lever  208  is shown in a third, clockwise-most angular position, which is clockwise relative to the second angular position shown in  FIG.  10   . The lever  208  may be prevented from rotating farther in the clockwise direction, such as by a mechanical stop  424 . In the illustrative embodiment, the angular difference between the second angular position and the third angular position is about 120 degrees. In alternative embodiments, the lever  208  may be configured for different angles of rotation. 
     Because the lever drive gear  416  is engaged with the lever idler gear  420  beginning when the lever  208  is in the second angular position, further rotation of the lever  208  in the clockwise direction beyond the second angular position to the third angular position causes rotation of the lever idler gear  420  and, accordingly, rotation of other components of the gear train  400  as described above. Specifically, rotation of the lever  208  in the clockwise direction from the second angular position ( FIG.  10   ) to the third angular position ( FIG.  11   ) causes rotation of the gear train  400  and the external generator shaft  402  ( FIG.  6   ) in one direction, and rotation of the lever  208  in the counter-clockwise direction, such as from the third angular position ( FIG.  11   ) to the second angular position ( FIG.  10   ) causes rotation of the gear train  400  and the external generator shaft  402  ( FIG.  6   ) in the opposite direction. Thus, rotational movement of the lever  208  between the second and third angular positions, regardless of direction, causes rotation of the external generator shaft  402  and production of electrical energy by the generator  404 . 
     As described below, in the illustrative embodiment, the lever  208  is rotated to retract the bolt  102  after the correct combination has been entered, and the lever  208  is rotated to extend the bolt  102  when the enclosure  10  is secured. In some embodiments, rotation of the lever  208  to retract and extend the bolt  102  over the course of one unlocking-locking operation may produce sufficient electrical energy to power the lock  100  for the next unlocking operation. In some embodiments, rotation of the lever  208  to retract and extend the bolt  102  over the course of one unlocking-locking operation may produce sufficient electrical energy to power a system real time clock until the next unlocking operation. 
       FIG.  12    is a simplified schematic diagram showing an illustrative electrical arrangement  450  for an electromechanical lock  100  ( FIG.  1   ), according to at least some aspects of the present disclosure. Electrical power sources, such as one or more generators  452  (e.g., generators  236 ,  404 ) and/or one or more photovoltaic arrays  454  (e.g., photovoltaic array  218 ) produce electrical energy, which is stored in one or more electrical energy storage devices  456  (e.g., a capacitor energy storage device, such as a super capacitor). The generator  452  may include, for example, a 3-phase motor generator with each phase coupled to the power bus via a rectifier. In some exemplary embodiments, electrical power may be routed between the interior of the securable enclosure and the exterior of the securable enclosure (and vice versa) via a power tube  464 . Electrical energy is provided for use by various components of the lock  100 , such as one or more processors  458  (e.g., processors  232 ,  234 ), one or more displays  460  (e.g., electronic display  214 ), and/or one or more components  462  of the lock assembly  300  (e.g., one or more motors and/or solenoids). Electrical energy may be supplied to various loads via one or more regulators, such as low voltage regulators  466 ,  468 . Electrical energy and/or signals may be conducted via a power tube, such as power tube  464 , or via any other desired manner such as standard cable, ribbon cable, or other electrical conductor components. 
     Generally, in the illustrative embodiment, the lever  208  may have two functions. First, the lever  208  is operative to generate electrical power, as the lever  208  is moved up and down. Typically, when an operator approaches the lock he or she will move the lever  208  down and up one time creating the power to operate the lock  100 . The operator enters the combination. Assuming the combination is correct “OP” may appear on the display  214  indicating the correct combination has been entered causing the bolt retraction mechanism to activate. As part of the second function, the operator will then move the lever  208  downward to a “down” or lowered position to mechanically retract the lock bolt  102 . The lever  208  will remain down as long as the lock  100  is unlocked. To lock the lock  100 , the operator will raise the lever  208  to an “up” or raised position, moving the lock bolt  102  to the locked position. With the lever  208  up, the lock  100  is ready for another unlocking cycle. Therefore, another result of the second function of the lever  208  is to give a visual indication of the lock status as “locked” or “unlocked.” To an observer (such as a security guard, for example), if the lever  208  is in the up position, the lock  100  is locked and may only be unlocked by entering the combination. However, if the lever  208  is in the down position, the lock  100  may be unlocked, or the lock  100  may be locked and the lever  208  may have been pushed down while the lock  100  was locked in order to generate power, for example. In this situation, the observer (such as the security guard) can more thoroughly check the status of the lock  100  and the secure enclosure or other protected area being secured by the lock  100 . If the lever  208  is in the raised or “up” position, the bolt  102  is extended and the secure enclosure or other protected area is secured. When operating the lever  208  to generate electrical power while the lock  100  is locked, the lever  208  may be lowered and raised and the bolt  102  will remain extended and the secure enclosure or other protected area will remain secured. 
       FIG.  13    is an isometric view of an alternative illustrative dial ring assembly  1200 , according to at least some aspects of the present disclosure. The dial ring assembly  1200  includes various alternative and/or optional features. Generally, the dial ring assembly  1200  may be similar in construction and/or operation to the dial ring assembly  200  described above. Unless specifically indicated, the description of the structure and function or methodology of corresponding components with respect to the dial ring assembly  200  generally applies to the dial ring assembly  1200 . Generally, the optional and/or alternative features described in connection with the dial ring assembly  1200  may be utilized in connection with other embodiments according to at least some aspects of the present disclosure, including the dial ring assembly  200  described above. 
     In some embodiments, the display  214  ( FIG.  2   ) may be replaced by a display  1214   a  oriented substantially parallel to the dial axis  206 . Such a display  1214   a  may face generally upward as shown in  FIG.  13   , or it may face generally laterally or generally downward, for example. Some alternative exemplary embodiments may include a display  1214   b  oriented substantially transverse to the dial axis  206 . 
     Some alternative exemplary embodiments may include a dial photovoltaic array  1218   a  disposed on the dial  204 , such as partially or fully circumferentially around the dial  204 . Various exemplary embodiments may include one or both of the dial ring photovoltaic array  218  and the dial photovoltaic array  1218   a.  In embodiments including a dial photovoltaic array  1218   a,  one or more brushes or other rotatable electrical connectors may be provided between the dial  204  and the housing  202  to allow electrical energy produced by the dial photovoltaic array  1218   a  to supply various electrical loads in the lock  100  ( FIG.  1   ). 
     Some embodiments may include a photovoltaic array  1218   b,  which may be mounted near the lock  100  to provide electrical energy to the lock  100 . The photovoltaic array  1218   b  may be positioned and oriented to receive incident light for producing electrical energy. For example, the photovoltaic array  1218   b  may comprise a panel attached to the exterior of the enclosure  10 , such as the front of the enclosure  10 . In some embodiments, the photovoltaic array  1218   b  may be positioned and/or oriented to receive incident light energy that would not be effectively collected by the dial ring photovoltaic array  218  and/or the dial photovoltaic array  1218   a,  such as due to the position and/or orientation of the dial ring assembly  1200  on the enclosure  10 . 
     Some exemplary embodiments may include at least one of a transmitter  500  and a receiver  502  configured for communication with a remote station  504 . The transmitter  500  and/or the receiver  502 , which may be combined into a transceiver, may be configured to communicate wirelessly with a communication unit  506 , and the communication unit  506  may be operatively connected to the remote station  504 . The remote station  504  may comprise a central monitoring facility, which may be operatively connected to an alarm system  508 . For example, the transmitter  500  may comprise an infrared transmitter and the receiver  502  may comprise an infrared receiver. The transmitter  500  and the receiver  502  may be configured to communicate with the communication unit  506  wirelessly using infrared data signals. The communication unit  506  may be disposed near the dial ring assembly  1200 , such as on the ceiling of a room containing the securable enclosure  10 . The communication unit  506  may be configured to communicate with a plurality of dial ring assemblies  1200 , and individual locks may be uniquely identified. The communication unit  506  may be configured to communicate with the remote station  504  using wired and/or wireless data transfer. In some example embodiments, the transmitter  500  may be configured to transmit data associated with various events, such as a locking event, an unlocking event, and/or a lock status report. The data may be transmitted upon the occurrence of an event, at periodic intervals, and/or upon being requested by the communication unit  506  and/or the remote station  504 . 
     Referring again to  FIGS.  1 - 4   , generally, the lock  100  may be operated as follows. A user may rotate and/or depress the dial  204  as necessary to enter the combination for the lock  100 . If necessary, the user may rotate the dial  204  and/or rotate the lever  208  to produce electrical energy for operation of the lock  100  prior to entering the combination. For example, the user may rotate the lever  208  clockwise and then counter-clockwise to generate power for operating the lock  100 , power being generated from the clockwise and counter-clockwise rotation. After the correct combination has been entered, the lock assembly  300  may operatively couple the spindle  224  to the bolt  102  to allow rotation of the lever  208  (e.g., clockwise) to retract the bolt  102 . After retracting the bolt  102  and operating other locking devices associated with the enclosure  10  (e.g., boltworks), the door  16  may be opened. 
     The enclosure  10  may be placed into a secured condition by shutting the door  16  and operating other locking devices associated with the enclosure  10 . Then, the user may extend the bolt  102  by rotating the lever  208  in the opposite direction (e.g., counter-clockwise). Once the bolt  102  has been extended and the lever  208  has been returned to the first angular position, the locking mechanism  300  may disconnect the spindle  224  from the bolt  102 , thereby securing the bolt  102  in the extended position. 
     Referring to  FIGS.  1 - 8   , a more detailed, illustrative method of operating the illustrative electromechanical combination lock  100  is described. The method may include entering a combination by rotating the dial  204 , including producing electrical energy by rotating the external generator shaft  402  of the external generator  404  and/or retracting the bolt  102  extending from the lock assembly  300  by rotating the lever  208  disposed on the dial ring assembly  200  about the lever axis  210 , including producing electrical energy by rotating the external generator shaft  402 . The method may include viewing at least one indicium  216  associated with the combination on the electronic display  214  disposed on the housing  202 . The method may include pushing the switch  205  in a single press. The method may include pushing the switch  205  in a double press to change between at least two modes. The method may include axially displacing the dial  204  along the dial axis  206  in a single press to actuate at least one switch  222   a,    222   b,    222   c,    222   d.  The method may include axially displacing the dial  204  along the dial axis  206  in a double press to change between at least two modes. The method may include rotating the lever  208  in a first direction to retract the bolt  102  and/or extending the bolt  102  by rotating the lever  208  in a second, opposite direction. 
     An illustrative method of manufacturing a security device is described. The method includes assembling a dial ring assembly  200 , including providing a housing  202 ; disposing an external generator  404  in the housing  202 ; rotatably disposing a dial  204  on the housing, rotatably disposing a lever  208  on the housing  202 ; and disposing a gear train  400  in the housing  202 . The method may include locating a switch  205  on the housing. The method may include disposing an electronic display  214  on the housing  202 . The method may include disposing a photovoltaic array  218 ,  1218   a  on the housing  202 , such as disposing the photovoltaic array  218  at least partially circumferentially around the housing  202  and/or disposing the photovoltaic array  1218   a  at least partially circumferentially around the dial  204 . The method may include installing the dial ring assembly  200  on an exterior of a wall  22  or a door  16  of a securable enclosure  10 , installing a lock assembly  300  on an interior of the wall  22  or the door  16 , and/or operatively connecting the dial ring assembly  200  and the lock assembly  300  through the wall  22  or the door  16 . The method may include installing a photovoltaic array  1218   b  comprising a photovoltaic panel on the securable enclosure  10  and/or operatively connecting the photovoltaic array  1218   b  to the dial ring assembly  200 . 
     An illustrative method of installing the illustrative lock  100  is described. The method includes mounting the dial ring assembly  200  on an exterior of a wall  22  or a door  16  of the securable enclosure  10 . The method may include mounting the lock assembly  300  on an interior of the wall  22  or the door  16  and/or operatively connecting the dial ring assembly  200  and the lock assembly  300  through the wall  22  or the door  16 . The method may include connecting the spindle  224  to the dial ring assembly  200  and the lock assembly  300 . The method may include installing the power tube  228  comprising at least one conductor  226  electrically connecting the dial ring assembly  200  and the lock assembly  300 . The method may include installing the photovoltaic array  1218   b  comprising a photovoltaic panel on the securable enclosure  10  and/or operatively connecting the photovoltaic array  1218   b  to the dial ring assembly  200 . 
     Some example locks according to at least some aspects of the present disclosure may be configured for operation in two or more modes. For example, some locks may be configured to facilitate both a single-user mode and a multi-user mode. In some circumstances, it may be desirable to limit which users may change the mode of operation of a multi-mode lock. Similarly, in some circumstances, it may be desirable to limit which users may activate audit trail functions and/or other operations. Accordingly, some locks may be configured to provide different capabilities to different users of the lock. For example, one level of capability may allow a user to change the combination, but not change other aspects of the operation of the lock. A second, higher level of capability may allow a user to change modes of operation, clear an audit trail, etc. In some embodiments, such different levels of capabilities may be facilitated by use of different change keys recognizable by the lock as being associated with different users with different levels of capabilities. In some embodiments, changing the mode of operation of a lock may require access to the interior of the securable enclosure. In some embodiments, some mode changes may require insertion of a change key, while other mode changes may require insertion of a change key and entry of a special, mode-change combination. In some embodiments, some mode changes may require a first special combination and other mode changes may require a second special combination. In alternative or additional aspects, the electronic display may be configured to display at least one indicium associated modes of operation. The display may include audible or other perceptible indicum associated with modes of operation. 
     As described above, some embodiments may be configured to utilize both alphabetic and numeric characters in combinations. The number of possible combinations for a three character alpha numeric combination is 2,000,376. Using a four character alpha numeric combination would yield a potential of 252,047,502 combinations. With that number of available combinations, a lock may accommodate at least ten users, each having a unique combination. In some embodiments, each user may be identified by a unique code, such as an alpha numeric code or other unique identifier, although this option may not be desired especially if each authorized user is instead given their own unique combination code for opening the lock. 
     Some embodiments may include an audit function. For example, an audit function package may allow security personnel to review both authorized lockings and unlockings, as well as unsuccessful attempts, each with date and time. In some embodiments, this functionality may be added to an existing lock with little, if any, modification to the lock. The audit function may utilize the real time clock described above. Access to read (e.g., extract) audit information may only be from inside the secured area. 
     Some locks may be configured for operation in connection with an external identification device, such as a biometric reader and/or a card reader. For example, the external device may act as a pre-approval for operation of the lock  100 . If an authorized biometric reading is obtained and/or an authorized card is presented, the lock may operate as described above. If the external device does not signal the lock that an authorized identification (e.g., biometric and/or card) is present, the lock may not power up and/or the display may not turn on, thus making operation (e.g., opening) of the lock impossible. 
     While the present invention has been illustrated by the description of specific embodiments thereof, and while the embodiments have been described in considerable detail, it is not intended to restrict or in any way limit the scope of the appended claims to such detail. The various features discussed herein may be used alone or in any combination within and between the various embodiments. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and methods and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the scope or spirit of the general inventive concept.