Patent Publication Number: US-11661771-B2

Title: Electronic drive for door locks

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to and the benefit of U.S. Provisional Patent Application No. 62/760,150, filed Nov. 13, 2018, and U.S. Provisional Patent Application No. 62/851,961, filed May 23, 2019, the disclosures of which are hereby incorporated by reference herein in their entirety. 
    
    
     INTRODUCTION 
     Doors commonly utilize locking devices on the locking stile that engage keepers mounted on the jamb frame to provide environmental control and security, and to prevent unintentional opening of the doors. Projecting handles, interior thumb-turns, and exterior key cylinders are commonly used devices to manually actuate the locking devices between locked and unlocked conditions and may also be used as a handgrip to slide the door open or closed. 
     SUMMARY 
     In an aspect, the technology relates to an electronic drive for a lock assembly including: a housing; a motor disposed within the housing; at least one link bar coupled to the motor and at least partially extending out of the housing; and a driven disk coupled to a first end of the at least one link bar and rotatable about a rotational axis, wherein the driven disk is adapted to couple to the lock assembly, and upon rotation, extend and retract at least one locking element, and wherein in operation, the motor selectively drives substantially linear movement of the at least one link bar to rotate the driven disk about the rotational axis. 
     In an example, a clutch assembly is coupled to a second end of the at least one link bar and disposed within the housing, wherein the rotational axis is a first rotational axis and the clutch assembly is rotatable about a second rotational axis. In another example, the housing defines a longitudinal axis, wherein the first rotational axis is parallel to and offset from the second rotational axis, and wherein the first rotational axis and the second rotational axis are both substantially orthogonal to the longitudinal axis. In yet another example, a worm drive is coupled between the motor and the clutch assembly. In still another example, the worm drive is selectively engageable with the clutch assembly. In an example, the worm drive is at least partially rotatable independently from the clutch assembly. 
     In another example, the clutch assembly is at least partially rotatable independently from the worm drive. In yet another example, the clutch assembly includes two disks coupled together by a tension system. In still another example, upon exceeding a predetermined load value, the two disks of the clutch assembly are independently rotatable. In an example, the electronic drive further includes a position sensor for determining a relative position of the clutch assembly. In another example, the position sensor is a mechanical switch. In yet another example, when the clutch assembly rotates about the second rotational axis, the corresponding rotation of the driven disk is in the same rotational direction. In still another example, the electronic drive further includes an access system remote from the housing, wherein the access system controls operation of the motor. 
     In another aspect, the technology relates to a door lock including: a mortise lock assembly including one or more locking elements; and an electronic drive coupled to the mortise lock assembly to extend and retract the one or more locking elements, wherein the electronic drive includes: a housing; a motor disposed within the housing; at least one link bar coupled to the motor and at least partially extending out of the housing; and a driven disk coupled to a first end of the at least one link bar and rotatable about a rotational axis, wherein the driven disk is coupled to the mortise lock assembly, and upon rotation, extend and retract the one or more locking elements, and wherein in operation, the motor selectively drives substantially linear movement of the at least one link bar to rotate the driven disk about the rotational axis. 
     In an example, the door lock further includes a faceplate, wherein the mortise lock assembly and the housing are both coupled to the faceplate. In another example, a thumbturn and/or a key cylinder is coupled to the driven disk. In yet another example, an access system is operatively coupled to the electronic drive and selectively drives operation of the motor. 
     In another aspect, the technology relates to a method of operating a lock assembly including: receiving at an access system an activation signal from a control element; detecting, by the access system, a presence of a security device relative to a door; determining, by the access system, a position of the security device relative to the door; determining, by the access system, an authorization of the security device; and rotating a driven disk coupled to the lock assembly based on the security device being (i) positioned proximate the door; (ii) located exterior to the door; and (iii) authorized to operate the access system, wherein the driven disk is coupled to a motor that drives rotation of the driven disk. 
     In an example, rotating the driven disk includes rotating a clutch assembly and substantially linearly moving a pair of link bars extending between the driven disk and the clutch assembly. In another example, after rotating the driven disk, positioning a worm drive coupled to the motor in a center neutral position. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       There are shown in the drawings, examples that are presently preferred, it being understood, however, that the technology is not limited to the precise arrangements and instrumentalities shown. 
         FIG.  1    is a perspective view of a sliding door assembly. 
         FIG.  2 A  is a side view of an electronic drive coupled to a lock assembly for use with the sliding door assembly of  FIG.  1   . 
         FIG.  2 B  is a rear view of the electronic drive coupled to the lock assembly. 
         FIG.  3 A  is a perspective view of the electronic drive shown in  FIG.  2 A . 
         FIGS.  3 B and  3 C  are perspective views the electronic drive with a portion of a housing removed. 
         FIG.  4    is a perspective view of a motor drive unit of the electronic drive shown in  FIG.  2 A . 
         FIG.  5    is an exploded perspective view of a clutch assembly and a worm gear of the motor drive unit shown in  FIG.  4   . 
         FIG.  6    is flowchart illustrating a method of operating a lock assembly. 
         FIG.  7    is a perspective view of another motor drive unit that can be used with the electronic drive shown in  FIG.  2 A . 
         FIG.  8    is an exploded perspective view of a clutch assembly and a worm gear of the motor drive unit shown in  FIG.  7   . 
         FIG.  9    is a front view of a lost motion disk of the clutch assembly shown in  FIG.  8   . 
     
    
    
     DETAILED DESCRIPTION 
       FIG.  1    is a perspective view of a sliding door assembly  100 . In the example, the sliding door assembly  100  includes a frame  102 , a fixed door panel  104 , and a sliding door panel  106 . The frame  102  includes a jamb  108  that the door panels  104 ,  106  are mounted within. The sliding door panel  106  includes a side stile  110 , and is laterally slidable in tracks  112  to open and close an opening  114  defined by the frame  102 . A handle assembly  116  and a lock assembly  118  are disposed on the side stile  110  and enable the sliding door panel  106  to be locked and unlocked from an exterior side and/or an interior side of the door. For example, the handle assembly  116  includes a thumbturn (not shown) and/or a key cylinder (not shown) that are coupled to the lock assembly  118  and enable locking members therein to be extended and/or retracted. 
     As described herein, an electronic drive may be coupled to the handle assembly  116  and/or the lock assembly  118  and enable remote and/or automatic locking and unlocking of the sliding door panel  106  without use of the thumbturn or key cylinder. The electronic drive is configured to be mounted within any number of door panel thickness, for example, panel thickness as small as 1½ inches, although other panel thickness are also contemplated herein. Additionally, the electronic drive may be coupled to any number of different types of lock assemblies  118  so it is adaptable to existing designs as a retrofit, as well as new designs as they come on the market. Accordingly, as home and commercial electronic lock systems are ever increasingly implemented and utilized, a single electronic drive may be used across a wide variety of door types and lock assembly types. 
       FIG.  2 A  is a side view of an electronic drive  200  coupled to a lock assembly  202  for use with the sliding door assembly  100  (shown in  FIG.  1   ).  FIG.  2 B  is a rear view of the electronic drive  200  coupled to the lock assembly  202 . Referring concurrently to  FIGS.  2 A and  2 B , the lock assembly  202  is a mortise-style door lock that is known in the art. That is, the lock assembly  202  is configured to couple to a rotatable thumbturn (not shown) and/or key cylinder (not shown) at a drive tail opening  204  so that rotation of the thumbturn or key cylinder rotates a component of the lock assembly  202  that extends and/or retracts locking elements  206  from a housing  210 . This allows the locking elements  206  to extend and retract through a faceplate  208 . In the example, the lock assembly  202  is AmesburyTruth&#39;s Nexus Series mortise lock that is a two-point or a multi-point lockset for sliding doors. In other examples, the lock assembly  202  may be AmesburyTruth&#39;s Gemini Series two-point mortise lock or a single-point mortise lock such as AmesburyTruth&#39;s 537 series, 555 series, 597 series, 840 series, 957 series, 1326 series, 2310 series, 2320 series, and 2321 series lock sets. In still other examples, the lock assembly  202  may be AmesburyTruth&#39;s P3000 series multi-point lock system. It is to be appreciated that the electronic drive  200  may be used with any number of lock assemblies  202  (e.g., AmesburyTruth&#39;s lock sets described above, any other lock set, or any other lock set from other manufacturers) that actuate the locking element  206  via a rotating motion R of an actuator. All of AmesburyTruth&#39;s locks are available from AmesburyTruth™ of Sioux Falls, S. Dak., by Amesbury Group, Inc. 
     In the example, the electronic drive  200  is configured to couple to the lock assembly  202  and enable actuation of the lock assembly  202  without use of the traditional thumbturn or key cylinder. However, the electronic drive  200  still enables use of the thumbturn or key cylinder as required or desired, for example, it still enables a drive tail to extend into the opening  204  for actuation of the lock assembly  202 . One challenge with the automation of door locks (e.g., providing an electronic motor for actuation thereof) is that doors are known to come in a wide variety of sizes (e.g., height, width, and thickness). As such, there are many known different styles and shapes of lock assemblies and designing for each and every different lock assembly with an electronic motor is undesirable. For example, one type of electronic motor configuration for a first lock assembly may not work in a second lock assembly because the door thickness is too small to accommodate the configuration. Additionally, with many different lock assembly configurations, the number of products and stock keeping units increase often exponentially, thereby decreasing manufacturing, shipping, and/or invoicing inefficiencies. Accordingly, the electronic drive  200  is configured to be used with many different types of lock assemblies  202  without significant or any changes thereto. This not only increases manufacturing efficiencies as existing mechanical door locks can still be used, but the electronic drive  200  enables for existing door locks to be upgraded with automated actuators as required or desired. 
     In the example, the electronic drive  200  includes a motor drive unit  212  with a pair of link bars  214  extending therefrom. The ends of the link bars  214  are coupled to a driven disk  216  that engages with the lock assembly  202  so the electronic drive  200  can actuate the lock assembly  202 . In one example, the driven disk  216  directly couples to an actuator component of the lock assembly  202 . In other examples, the driven disk  216  couples to the drive tail (not shown) of the thumbturn and or key cylinder such that the driven disk  216  drives movement thereof. In either configuration, the opening  204  of the lock assembly  202  is left unimpeded so that manual actuation of the lock assembly  202  may still occur via a drive tail extending therethrough. In the example, the faceplate  208  of the lock assembly  202  may be extended so that the motor drive unit  212  can be supported on the lock assembly  202 . This enables the lock assembly  202  and the electronic drive  200  to be installed into the door as a single unit. In other examples, the motor drive unit  212  need not couple to the faceplate  208  of the lock assembly  202  and may include its own faceplate (not shown) so it can be mounted separately on the door. In the example, the electronic drive  200  can be positioned below the lock assembly  202  (as illustrated), or may be positioned above the lock assembly  202  as required or desired. 
     In operation, the lock assembly  202  can be operated from an interior side or an exterior side of the door by a handle assembly (e.g., the handle assembly  116  shown in  FIG.  1   ). To unlock from the interior side, a thumbturn (not shown) may be coupled to the lock assembly  202  by a drive tail within the opening  204  so that rotational movement of the thumbturn may extend or retract the locking elements  206 . In other examples, the thumbturn may be a thumb slide so that linear movement may induce corresponding rotation of the drive tail by a linkage system. To operate from the exterior side, a key rotating a key cylinder (not shown) may be coupled to the lock assembly  202  by a drive tail within the opening  204  so that rotational movement of the key cylinder may extend or retract the locking elements  206 . One example of a handle assembly is described in U.S. patent application Ser. No. 16/045,161, filed Jul. 25, 2018, entitled “ACCESS HANDLE FOR SLIDING DOORS,” and the disclosure of which is hereby incorporated by reference herein in its entirety. 
     Additionally or alternatively, the lock assembly  202  can be automatically actuated by the electronic drive  200 . By including the electronic drive  200 , the door is enabled to be locked and unlocked from either the exterior or interior side without use of a manual key within the key cylinder or the thumbturn. The electronic drive  200  is configured to motorize the locking and unlocking of the lock assembly  202  so that only a control element (e.g., a button or touch pad) needs to be actuated, thereby simplifying and automating door lock use for the user. Additionally, to provide security to the electronic drive  200 , access control authentication for the control element may be provided by a security device  218  (shown in  FIG.  2 A ). For example, the security device  218  may be a mobile device such as a phone or a key fob that can communicate with the electronic drive  200  by sending communication signals through wireless communication protocols (e.g., Bluetooth communication protocols). Accordingly, use of a physical key is no longer necessary to unlock the door. This enables multiple users (e.g., several members of a family) to each have access while reducing the risk of physical keys being lost or stolen. Additionally, controlled access (e.g., for one time access, a set number of uses, or a set day or time of day) can be set up so that users, such as dog walkers, house sitters, or cleaners, can have limited access through the door. Furthermore, records of who accessed the door and at what time may be compiled and/or stored. 
     The electronic drive  200  and the lock assembly  202  are configured to be mounted on a locking edge of the side stile. That is, the faceplate  208  is substantially flush with the surface of the door and the electronic drive  200  and the lock assembly  202  are at least partially recessed within the door. Since the electronic drive  200  can be used with any number of lock assemblies, as described in detail above, it is sized and shaped for use in a wide variety of door thicknesses. For example, the electronic drive  200  has a thickness T (shown in  FIG.  2 B ) that is approximately 1 inch, and as such, it is enabled for use in narrower doors that are about 1½ inch thick. Generally, sliding doors are known to have thicknesses as small as 1½-1¾ inches, and for comparison, the access handle described in U.S. patent application Ser. No. 16/045,161, filed Jul. 25, 2018, requires at least a 2¼ inch thick door panel because of the configuration and orientation of the components therein. In order to use the electronic drive  200  for different lock assemblies  202 , the length of the link bars  214  and the driven disk  216  are the only components that are required to be changed or modified so that various drive tail openings  204  of the lock assemblies  202  can be accommodated. 
     The electronic drive  200  may be battery operated or line voltage operated via the structure&#39;s power source as required or desired. In either configuration, an access system  220  may be electrically and/or communicatively coupled to the electronic drive  200  by wired or wireless protocols. For the battery operated configuration, the power supply (e.g., 4 AA batteries) may be disposed within the access system  220 . In the example, the access system  220  may include one or more device sensors configured to communicate with and detect the security device  218 , a control element (e.g., a touch pad, a button, an infrared beam, etc.) configured to activate the electronic drive  200  without requiring physical keys, a notification system configured to display at least one status condition, and one or more printed circuit boards that mechanically support and electrically connect one or more electronic components or electrical components that enable operation of the access system  220  described herein. For example, electronic/electrical components may include memory, processors, light emitting diodes (LED), antennas, communication and control components, etc., coupled to a printed circuit board. 
     In the example, the access system  220  may be a separate unit from the electronic drive  200  so that it can be mounted away from the lock assembly  202  and enable the sensors and antennas to function without interference. Furthermore, this configuration enables the control element to be positioned on the door and at a location that facilitates ease of use for the user. In other examples, the access system  220  may be integrated with a handle assembly, for example, the handle assembly  116  described above in  FIG.  1   . For example, the handle assembly may include the device sensor on an interior escutcheon, the control element on an exterior escutcheon, and the notification system on one or both of the interior escutcheon and the exterior escutcheon. This configuration enables for various handle styles to be used with the electronic drive  200  as required or desired. 
     To remotely operate the lock assembly  202 , the control element (e.g., mounted on the handle assembly) that is operatively coupled to the access system  220  and the electronic drive  200  may be used. When the control element is actuated, a signal is sent to the access system  220  to drive the electronic drive  200  and rotate the driven disk  216  to either lock or unlock the locking elements  206 . For example, based on the position of the motor drive unit  212 , the access system  220  can determine that the locking elements  206  are in a locked position, and thus, move the motor drive unit  212  so that the locking elements  206  are moved towards an unlocked position, or determine that the locking elements  206  are in an unlocked position, and thus, move the motor drive unit  212  so that the locking elements  206  are moved towards a locked position. The access system  220  may then also display one or more status conditions (e.g., “locked” or “unlocked”) of the electronic drive  200  at the notification system. Because the control element can be a single button actuator (e.g., a touch pad) that is disposed on the exterior side of the handle assembly, the electronic drive  200  is easy to operate. In order to lock and unlock the lock assembly  202 , a user need only to press the control element without having to enter an access code or have a physical key. In other examples, a button, a switch, a sensor, or other signal-sending device may be used in place of the touch pad as required or desired. However, for security and/or any other reasons, the access system  220  is configured to restrict control of the control element to only authorized users. This enables the access system  220  to prevent unauthorized access through the door, while still utilizing a single control element for ease of use. 
     To provide user authorization of the electronic drive  200  and the access system  220 , the security device  218  can be used. The security device  218  may be a mobile device such as a phone or a key fob that can wirelessly communicate with the access system  220 . Before using the electronic drive  200 , one or more security devices  218  can be linked (e.g., authenticated) with the access system  220  so that access through the door is restricted and not available to everyone. For example, a small aperture (e.g., the size of a paper clip) may be located within the access system  220  that enables access to a small button, and when pressed, begins the authentication process for the security device  218 . In one example, once the security device  218  is authenticated with the access system  220 , an authentication code can be stored in the security device  218  so that the access system  220  can search and determine if the security device  218  matches an authorized device when the control element is actuated. In other examples, any other authorization protocols may be used to link the security device  218  and the access system  220  as required or desired. 
     When the security device  218  includes key fobs for use with the access system  220 , the key fob may be pre-loaded with an authentication code that is uploaded to the access system  220  for subsequent authorization determinations. Authentication may also be provided by a dedicated computer application on the security device  218  (e.g., mobile phone) that can connect to the access system  220 . Use of the application enables an intuitive user interface to manage authenticated devices with the access system  220  and facilitate ease of use of the electronic drive  200 . 
     After the initial setup between the security device  218  and the access system  220 , access through the door is easy to operate via the control element. Additionally, the communication transmitted between the security device  218  and the access system  220  can be encrypted with high-level encryption codes and provide resistance to malicious intrusion attempts. In comparison with other systems (e.g., an electronic lock keypad), the user interface is greatly simplified with a control element and use of an application to manage the authenticated device(s). 
     In other examples, the access system  220  can be configured (e.g., through the user interface application) to temporarily enable the control element without requiring the security device  218 . This can enable third parties (e.g., repair people, dog walkers, movers, etc.) to have temporary access to the door as required or desired while still maintaining security of the electronic drive  200 . For example, the control element may be enabled for a predetermined number of uses, a predetermined date/time range for use, or a one-time only use without the security device  218  being present. In still other examples, the access system  220  may generate temporary authorization codes (e.g., through the user interface application) that can be sent to third parties for temporary access to the door. These temporary authorization codes may be enabled for a predetermined number of uses or a predetermined date/time range for use. 
     The access system  220  (e.g., via one or more antennas (not shown)) can have a predetermined range area (e.g., approximately 10 feet, 15 feet, 20 feet, etc.) such that the security device  218  must be present within the range area in order for the access system  220  to authorize the security device  218  and to be enabled for the operation of the electronic drive  200 . In some examples, the range area of the access system  220  may be user defined, for example, through the application user interface. By defining the range area of the access system  220 , the operation of the electronic drive  200  can be limited to only when the security device  218  is located proximate the access system  220 . This reduces the possibility of the control element being enabled after authorized users leave the door area or when authorized users are merely walking by the door. 
     In addition to the access system  220  detecting the presence of the security device  218 , the access system  220  also can determine a position of the security device  218  relative to the door so that the access system  220  is not enabled when authorized users are located on the interior side of the door. As such, an unauthorized user cannot lock and/or unlock the lock assembly  202  when an authorized user is inside and proximate the access system  220 . In the example, the access system  220  can determine whether the security device  218  is disposed on an exterior side of the door or disposed on an interior side of the door. 
     In operation, upon actuation of the control element, the access system  220  is configured to detect a presence of the security device  218  to verify that the security device  218  is within range; determine a position of the security device  218  relative to the access system  220  (e.g., on the interior or exterior side of the sliding door); and determine whether the security device  218  is authorized for use with the access system  220 . When there is an authorized device within range and adjacent to the exterior of the door, the access system  220  will engage the lock assembly  202  and lock or unlock the door. It should be appreciated that the access system  220  may perform any of the above operation steps in any sequence as required or desired. For example, the access system  220  may automatically search for the security devices  218  at predetermined time periods (e.g., every 10 seconds). Thus, the access system  220  can pre-determine whether an authorized device is present and outside of the door before the control element is actuated. In other examples, the access system  220  may first determine authorization of the security device  218  and then determine its relative position before enabling operation of the electronic drive  200 . 
     In some examples, the notification system of the access system  220  may provide an audible and/or visual indicator during the operation of the electronic drive  200 . This enables audible and/or visual feedback for users during control of the lock assembly  202  by the access system  220 . Additionally, although the door is described as having an interior and exterior side, these orientations are merely for reference only. Generally, the access system  220  and electronic drive  200  may be used for any door, gate, or panel that separates a controlled access area from an uncontrolled access area, whether it is inside a structure, outside of a structure, or between the inside and outside of a structure. Examples of systems that have similar operation with the access system  220  described herein (e.g., using the security device  218  to determine access and the locking/unlocking of the lock assembly  202 ) are U.S. patent application Ser. No. 16/045,161, filed Jul. 25, 2018, entitled “ACCESS HANDLE FOR SLIDING DOORS” and U.S. patent application Ser. No. 16/014,963, filed Jun. 21, 2018, entitled “GARAGE DOOR ACCESS REMOTE,” both disclosures of which is hereby incorporated by reference herein in there entireties. 
       FIG.  3 A  is a perspective view of the electronic drive  200 . As described above, the electronic drive  200  includes the motor drive unit  212 , the pair of link bars  214  extending therefrom, and the driven disk  216 . The motor drive unit  212  includes a housing  222  that may be coupled to the faceplate  208  (shown in  FIGS.  2 A and  2 B ) by one or more fasteners  224 . The housing  222  may be a two-piece housing that can snap-fit together and enable access to the components contained therein. Extending from an end portion  226  of the housing  222  are the pair of link bars  214 . The link bars  214  are disposed proximate a first side  228  of the housing  222  and offset from a centerline thereof. This position of the link bars  214  enables the driven disk  216  to be coupled to the lock assembly  202  (shown in  FIGS.  2 A and  2 B ) along its side and reduce the thickness T of the electronic drive  200 . Furthermore, the link bars  214  may include one or more dog-leg sections that enable the driven disk  216  to be positioned over the end portion  226  of the housing  222  and maintain the reduced thickness T of the electronic drive  200 . 
     The link bars  214  are configured to extend from and retract into (e.g., arrows  230 ,  232 ) the housing  222 . In the example, the link bars  214  are configured to move in opposite directions, and when one link bar retracts the other link bar is extending. The free end of each link bar  214  is coupled to the driven disk  216  at a pivot point  234 . The substantially linear movement  230 ,  232  of the link bars  214  induce a corresponding rotational movement  236  into the driven disk  216  so as to operate the lock assembly  202  (shown in  FIGS.  2 A and  2 B ) as required or desired. The driven disk  216  is configured to couple to the exterior of the lock assembly  202  (e.g., directly or via a drive tail) and also has an opening  238  so that a drive tail from a thumbturn or a key cylinder (both not shown) can still be used for manual lock assembly operation. 
       FIGS.  3 B and  3 C  are perspective views the electronic drive  200  with a portion of the housing  222  removed. Referring concurrently to  FIGS.  3 B and  3 C , the housing  222  defines an interior cavity  240  in which the motor drive unit  212  is disposed. Additionally, the housing  222  defines a longitudinal axis  242  that is substantially orthogonal to the end portion  226  of the housing  222 . The motor drive unit  212  includes a motor  244  that is configured to rotatably drive a motor shaft (not shown) extending substantially parallel to the longitudinal axis  242 . The motor  244  may be an off-the-shelf DC unit that includes an integral gear set  246  surrounded by a chassis  248  and is communicatively and/or electrically coupled to a printed circuit board (PCB)  250  supported within the housing  222 . The PCB  250  is configured to control operation of the motor  244  and/or provide feedback to other controller components (e.g., the access system  220  (shown in  FIGS.  2 A and  2 B )), and includes any number of components that enable this function and operation. For example, the PCB  250  may include one or more resistors, light emitting diodes, transistors, capacitators, inductors, diodes, switches, power supply, connectors, speakers, antennas, sensors, memory, processors, etc. In one example, a position sensor  251  may be included so as to determine a position of one or more components of the motor drive unit  212 . 
     In the example, the motor  244  is coupled to the driven disk  216  via a worm drive  252  and the pair of link bars  214  so that the motor  244  can drive rotation of the driven disk  216  about a first rotational axis  254 . The first rotational axis  254  is substantially orthogonal to the longitudinal axis  242 . The worm drive  252  includes a worm  256  coupled to the motor shaft and is rotatably driven by the motor  244 . The motor  244  can rotate the worm  256  in either direction (e.g., clockwise or counter-clockwise) so that the electronic drive  200  can both lock and unlock the lock assembly  202  (shown in  FIGS.  2 A and  2 B ). The worm  256  meshes with a worm gear  258  that is coupled to a clutch assembly  260 . The worm gear  258  and the clutch assembly  260  are supported on a spindle  262  that defines a second rotational axis  264 . The second rotational axis  264  is substantially parallel to and offset from the first rotational axis  254  and both are substantially orthogonal to the longitudinal axis  242 . Each link bar  214  is coupled to the clutch assembly  260  at pivot points  266  and the link bars  214  extend substantially parallel to the longitudinal axis  242 . As illustrated in  FIGS.  3 B and  3 C , the worm drive  252  is the gear arrangement that translates movement generated by the motor  244  to the driven disk  216 . Additionally or alternatively, any other gear arrangement that enables operation of the electronic drive  200  as described herein may be used as required or desired. 
     In operation, the electronic drive  200  couples to the lock assembly  202  and is configured to automatically extend and/or retract the locking elements therefrom. More specifically, upon the motor  244  driving rotation of the worm  256 , the worm gear  258  and the clutch assembly  260  rotate  268  about the second rotational axis  264  and the spindle  262 . The rotational movement  268  of the clutch assembly  260  drives opposing linear movement  230 ,  232  of the pair of link bars  214  along the longitudinal axis  242 . That is one link bar  214  moves in a first direction along the longitudinal axis  242  and the other link bar  214  moves in an opposite second direction along the longitudinal axis  242 . This linear movement of the link bars  214  translates the rotational movement  268  of the clutch assembly  260  into a corresponding rotation  236  of the driven disk  216  around the first rotational axis  254  for actuation of the lock assembly  202 . In the example, both the clutch assembly  260  and the driven disk  216  rotate in the same direction during operation. Furthermore, it is appreciated that since the pivot points  234 ,  266  rotate with the clutch assembly  260  and the driven disk  216 , respectively, this rotational movement not only linearly moves  230 ,  332  the link bars  214 , but also slightly translates  270  the link bars  214  away or towards each other as well. However, the linear movement  230 ,  232  distance is much greater than the translational movement  270  distance. 
     Additionally, the electronic drive  200  enables for the lock assembly  202  to be manually extended and/or retracted as required or desired. Accordingly, the electronic drive  200  is configured to enable manual rotation of a portion of the motor drive unit  212  without affecting operation of the automatic portion of the motor drive unit  212  as described above. In the example, the driven disk  216  may be coupled to a thumbturn and/or a key cylinder (both not shown) that are used to manually rotate  236  the driven disk  216  about the first rotational axis  254 . The rotational movement  236  of the driven disk  216  drives opposing linear movement  230 ,  232  of the pair of link bars  214  along the longitudinal axis  242  and this linear movement induces rotational movement  268  of the clutch assembly  260  about the second rotational axis  264  and the spindle  262 . However, the clutch assembly  260  is configured to prevent the rotational movement  268  to be transferred to the worm gear  258  so that the worm  256  is not manually rotated and undesirable wear is not induced into the motor  244  and the gear set  246 . The worm gear  258  and the clutch assembly  260  are described further below. 
       FIG.  4    is a perspective view of the motor drive unit  212  of the electronic drive  200  (shown in  FIGS.  3 A- 3 C ) with the driven disk  216  and housing  222  not shown for clarity. As described above, the motor drive unit  212  includes the motor  244  coupled to the worm  256  with both extending substantially orthogonal to the spindle  262 . Attached to the spindle  262  is the worm gear  258  and the clutch assembly  260  that has the link bars  214  extending therefrom. The worm  256  and the worm gear  258  from the worm drive  252 . The clutch assembly  260  includes an arm  272  that extends towards the PCB  250  (shown in  FIGS.  3 B and  3 C ) and engages with the position sensor  251  (shown in  FIG.  3 C ) so that the position of the clutch assembly  260 , and thereby, the lock assembly  202  (shown in  FIGS.  3 B and  3 C ), can be determined. The position sensor may be a mechanical switch, a magnetic sensor, or any other sensor that enables the position of the clutch assembly  260  to be determined. In the example, the arm  272  engages with a mechanical switch in order to provide feedback as to the position of the clutch assembly  260 . By using a mechanical switch, interference in the PCB  250  by magnetic fields (e.g., by a magnetic sensor) is reduced, and thereby, increases the performance of the electronic drive  200 . 
     In operation, after the clutch assembly  260  is rotated by the motor  244  to actuate the lock assembly  202  and extend or retract the locking elements, the motor drive unit  212  automatically returns to a centered neutral position. By returning to this position, the clutch assembly  260  is configured to rotate due to manual rotation (e.g., by the thumbturn or key cylinder) without rotating the worm gear  258  and inducing undesirable wear into the motor  244 . Additionally or alternatively, the worm drive  252  may be replaced by, or augmented by, any other mechanical linkage (e.g., drive bar, helical gears, spur gears, etc.) that enable the motor drive unit  212  to function as described herein. 
       FIG.  5    is an exploded perspective view of the clutch assembly  260  and the worm gear  258 . The worm gear  258  includes a first end defining a circumferential rack  274  that engages with the worm  256  and forms the worm drive  252  (both shown in  FIG.  4   ). An opposite second end of the worm gear  258  includes a drive hub  276  with at least one drive lug  278  extending therefrom. In the example, the drive hub  276  has two drive lugs  278  that are spaced approximately 180° from one another. The drive hub  276  and the drive lugs  278  are sized and shaped to be received in a first end of the clutch assembly  260  so as to drive rotation of the clutch assembly via the motor  244  (shown in  FIG.  4   ). 
     The clutch assembly  260  includes a clutch disk  280  that is coupled to a lost motion disk  282 . A first end of the lost motion disk  282  includes a driven hub  284  with at least one driven lug  286  extending therefrom. In the example, the driven hub  284  has two driven lugs  286  that are spaced approximately 180° from one another. The driven hub  284  is configured to receive at least a portion of the drive hub  276  of the worm gear  258 . However, when the drive hub  276  is engaged with the driven hub  284 , the lugs  278 ,  286  are not necessary engaged. The circumferential spacing of the lugs  278 ,  286  (e.g., each set being positioned at 180° from each other) enables the clutch assembly  260  to at least partially freely rotate relative to the worm gear  258  before the lugs  278 ,  286  engage. For example, the drive hub  276  or the driven hub  284  may freely rotate approximately 90° before the lugs  278 ,  286  engage with each other and rotational movement is transferred between the clutch assembly  260  and the worm gear  258 . 
     In the example, this free rotation between the hubs  276 ,  284  is enabled because in a centered neutral position, the drive lugs  278  are spaced approximately 90° from the driven lugs  286 . The free rotation enables for the worm gear  258  to return to the centered neutral position after extending or retracting (e.g., both rotation directions) the lock assembly  202  (shown in  FIGS.  2 A and  2 B ) without further rotating the clutch assembly  260 , and thereby, the lock assembly. Additionally, once the worm gear  258  is in the centered neutral position, manual rotation of the clutch assembly  260  (e.g., by the thumbturn or the key cylinder) in either rotation direction does not cause corresponding rotation of the worm gear  258 , and thereby, undesirable wear to the motor  244 . 
     The clutch disk  280  is coupled to the lost motion disk  282  by a tension system having a ball  288  and a spring  290 . This tension system enables the clutch assembly  260  to rotate as a single unit under typical operating conditions. However, if the motor  244  and/or the worm drive  252  binds up in a position other than the centered neutral position (e.g., in a position where the lugs  278 ,  286  are engaged or partially engaged), then the tension system releases the coupling between the clutch disk  280  and the lost motion disk  282  upon reaching a predetermined load value to reduce or prevent undesirable wear to the motor  244 . For example, if the worm gear  258  is in a position other than the center neutral position when the clutch assembly  260  is manually rotated (e.g., via use of the thumbturn or key-cylinder), once the manual rotation induces a predetermined load (e.g., greater than the pre-tensioning of the tension system) to the clutch disk  280 , then the tension system releases the coupling between the clutch disk  280  and the lost motion disk  282 . Once the clutch disk  280  is rotationally decoupled from the lost motion disk  282 , the lock assembly  202  can continue to be manually operable without inducing undesirable wear on the drive system components. After the manually induced load on the clutch disk  280  is released, then the tension system can return to rotationally coupling the clutch disk  280  together with the lost motion disk  282  as a single unit. 
     In the example, a first end of the clutch disk  280  includes one or more pockets  292  defined therein. The pockets  292  are sized and shaped to receive and engage the balls  288  that are engaged with the spring  290 . The spring  290  is received and engage within a corresponding recess  294  defined in a second end of the lost motion disk  282 . The spring  290  provides a tension force that secures the clutch disk  280  and the lost motion disk  282  together so they rotate as a single unit (e.g., the clutch assembly  260 ) and enable operation of the drive as described herein. However, once the tension force is overcome, the clutch disk  280  may at least partially rotate separately from the lost motion disk  282 . The second end of the clutch disk  280  couples to the link bars  214  (shown in  FIGS.  3 A- 3 C ) with the pivot points  266  and includes the arm  272  that facilitates determining the position of the clutch assembly  260  as described herein. 
     The clutch assembly  260  and the worm gear  258  are rotationally supported on the spindle  262  and secured in place by an E-clip  296 . A fastener  298  may be used to couple the clutch assembly  260 , worm gear  258 , and spindle  262  to the housing  222  (shown in  FIGS.  2 A and  2 B ). In an example, this spindle component assembly may be assembled separately from the rest of the components of the electronic drive  200  (shown in  FIGS.  3 A- 3 C ) so that the tension system can be more easily installed and compressed to pre-load the clutch assembly  260 . This can facilitate more efficiencies in the manufacturing process. 
       FIG.  6    is flowchart illustrating a method  300  of operating a lock assembly. The method  300  begins with actuating a control element of an access system (operation  302 ). Once the control element is pressed a signal is sent and received at the access system that controls operation of an electronic drive. Upon receipt of a signal, the access system detects a presence of a security device relative to the door (operation  304 ). If the access system detects that no security device is present within its range, then a status condition (e.g., an error indication) of the electronic drive may be indicated on the notification system (operation  306 ). 
     However, when the access system detects that there is a security device present, then the access system determines a position of the security device relative to the door (operation  308 ). If the access system determines that the security device is inside of the door, then a status condition of the electronic drive assembly may be indicated on the notification system (operation  306 ). However, when the security device is present and outside of the door, then the access system determines an authorization of the security device (operation  310 ). If the access system determines that the security device is unauthorized, then a status condition of the electronic drive may be indicated on the notification system (operation  306 ). 
     When the security device is positioned proximate the access system, located on the exterior of the door, and authorized to operate the electronic drive, the electronic drive can be operated and a status condition (e.g., a success indication) indicated on the notification system (operation  312 ). For example, the success indication can be a notification that the lock assembly is locking if originally unlocked or unlocking if originally locked. In some examples, operating the electronic drive can further include rotating a clutch assembly coupled to a pair of link bars, and after moving the lock assembly to one of a locked position and an unlocked position, returning the clutch assembly to a center neutral position. While operations  304 ,  308 ,  310  are illustrated as being in order in  FIG.  6   , it is appreciated that these operations may be performed at any time and in any order as required or desired. Once the lock assembly is to be locked or unlocked, the method  300  further includes sensing a position of the electronic drive by a sensor (operation  314 ). As such, when the lock assembly is locked, the access system operates the lock assembly to unlock (operation  316 ), and when the lock assembly is unlocked, the access system operates the lock assembly to lock (operation  318 ). 
       FIG.  7    is a perspective view of another motor drive unit  400  that can be used with the electronic drive  200  (shown in  FIGS.  3 A- 3 C ). Similar to the example described above in reference to  FIGS.  4  and  5   , the motor drive unit  400  includes a motor  402  coupled to a worm  404  with both components extending substantially parallel to the longitudinal axis of the drive housing (not shown) and extending substantially orthogonal to a spindle  406  that defines a rotational axis  408 . Attached to the spindle  406  is a worm gear  410  and a clutch assembly  412  that has two link bars  414  extending therefrom. The link bars  414  are coupled to a driven disk  416  that is rotatable about a rotational axis  418 . The worm  404  and the worm gear  410  form a worm drive  420 . The clutch assembly  412  includes an arm  422  oriented to engage with a position sensor (e.g., the sensors  251  shown in  FIG.  3 C ) so that the position of the clutch assembly  412  can be determined. For example, a rotational position of the clutch assembly  412  can be determined so that locking/unlocking operations can be performed by the electronic drive as described herein. 
     In operation, after the clutch assembly  412  is rotated by the motor  402  to actuate the lock assembly  202  (shown in  FIG.  2 A ) and extend or retract the locking elements, the motor drive unit  400  automatically returns to a centered neutral position. By returning to this position, the clutch assembly  412  is configured to rotate due to manual rotation (e.g., by the thumbturn or key cylinder) without rotating the worm gear  410  and inducing undesirable wear into the motor  402 . Additionally or alternatively, the worm drive  420  may be replaced by, or augmented by, any other mechanical linkage (e.g., drive bar, helical gears, spur gears, etc.) that enable the motor drive unit  400  to function as described herein. 
     Additionally, in this example, the configuration of the clutch assembly  412  is thinner along a direction  423  extending substantially parallel to and along the rotational axis  408 , when compared to the clutch assembly  260  described in  FIGS.  4  and  5    above. By reducing the thickness of the clutch assembly  412 , the thickness T of the housing of the electronic drive  200  (shown in  FIG.  2 B ) is further reduced. This increases the performance and efficiency of the electronic motor drive (e.g., manufacturing, installation, operation, etc.). 
       FIG.  8    is an exploded perspective view of the clutch assembly  412  and the worm gear  410  of the motor drive unit  400  (shown in  FIG.  7   ). The worm gear  410  includes a first end defining a circumferential rack  424  that extends at least partially around a perimeter of the gear  410  and engages with the worm  404  and forms the worm drive  420  (both shown in  FIG.  7   ). An opposite second end of the worm gear  410  includes a drive hub  426  with at least one drive lug extending therefrom. In the example, the drive hub  426  has two drive lugs that are spaced approximately 180° from one another and similar to the example described above in  FIG.  5   . The drive hub  426  and the drive lugs are sized and shaped to be received in a first end of the clutch assembly  412  so as to drive rotation of the clutch assembly via the motor  402  (shown in  FIG.  7   ). Additionally, an arm  428  may extend from the first end of the worm gear  410  and is oriented to engage with a position sensor (e.g., the sensors  251  shown in  FIG.  3 C ) so that a position of the worm gear  410  can be determined. For example, a rotational position of the worm gear  410  can be determined so that locking/unlocking operations can be performed by the electronic drive as described herein. 
     The clutch assembly  412  includes a clutch disk  430  that is coupled to a lost motion disk  432 . A first end of the lost motion disk  432  includes a driven hub  434  with at least one driven lug  436  extending therefrom. In the example, the driven hub  434  has two driven lugs  436  that are spaced approximately 180° from one another and similar to the example described above in  FIG.  5   . The driven hub  434  is configured to receive at least a portion of the drive hub  426  of the worm gear  410 . However, when the drive hub  426  is engaged with the driven hub  434 , the lugs are not necessary engaged. The circumferential spacing of the lugs (e.g., each set being positioned at 180° from each other) enables the clutch assembly  412  to at least partially freely rotate relative to the worm gear  410  before the lugs engage. For example, the drive hub  426  or the driven hub  434  may freely rotate approximately 90° before the lugs engage with each other and rotational movement is transferred between the clutch assembly  412  and the worm gear  410 . 
     The free rotation between the hubs  426 ,  434  is enabled because in the centered neutral position, the drive lugs are spaced approximately 90° from the driven lugs. The free rotation enables for the worm gear  410  to return to the centered neutral position after extending or retracting (e.g., both rotation directions) the lock assembly  202  (shown in  FIGS.  2 A and  2 B ) without further rotating the clutch assembly  412 , and thereby, the lock assembly. Additionally, once the worm gear  410  is in the centered neutral position, manual rotation of the clutch assembly  412  (e.g., by the thumbturn or the key cylinder) in either rotation direction does not cause corresponding rotation of the worm gear  410 , and thereby, undesirable wear to the motor  402 . Additionally, the rotational position of the clutch assembly  412  and the worm gear  410  can be determined by position sensors and the arms  422 ,  428  and enable operation of the system. 
     In this example, the clutch disk  430  is coupled to the lost motion disk  432  by a tension system having resilient spring fingers  438  of the lost motion disk  432  configured to engage with corresponding notches  440  within the clutch disk  430 . This tension system enables the clutch assembly  412  to rotate as a single unit under typical operating conditions. However, if the motor  402  and/or the worm drive  420  binds up in a position other than the centered neutral position (e.g., in a position where the lugs are engaged or partially engaged), then the tension system releases the coupling between the clutch disk  430  and the lost motion disk  432  upon reaching a predetermined load value to reduce or prevent undesirable wear to the motor  402 . For example, if the worm gear  410  is in a position other than the center neutral position when the clutch assembly  412  is manually rotated (e.g., via use of the thumbturn or key-cylinder), once the manual rotation induces a predetermined load (e.g., greater than the pre-tensioning of the tension system) to the clutch disk  430 , then the tension system releases the coupling between the clutch disk  430  and the lost motion disk  432 . Once the clutch disk  430  is rotationally decoupled from the lost motion disk  432 , the lock assembly  202  can continue to be manually operable without inducing undesirable wear on the drive system components. After the manually induced load on the clutch disk  430  is released, then the tension system can return to rotationally coupling the clutch disk  430  together with the lost motion disk  432  as a single unit. 
     In the example, a first end of the clutch disk  430  is recessed so that at least a portion of the lost motion disk  432  is disposed within. One or more notches  440  radially extend from the recess and are circumferentially spaced around the perimeter of the clutch disk  430 . The notches  440  are sized and shaped to receive and engage the spring fingers  438 . When the spring fingers  438  are engaged with the notches  440 , the spring fingers  438  provide a tension force that secures the clutch disk  430  and the lost motion disk  432  together so they rotate as a single unit (e.g., the clutch assembly  412 ) and enable operation of the drive as described herein. However, once the tension force is overcome (e.g., overcoming the biasing force of the fingers  438 ), the clutch disk  430  may at least partially rotate separately from the lost motion disk  432 . The second end of the clutch disk  430  couples to the link bars  414  (shown in  FIG.  7   ) and includes the arm  422  that facilitates determining the position of the clutch assembly  412  as described herein. Additionally, in this example, the thickness of the clutch assembly  412  along the rotation axis (e.g., the lost motion disk  432  received at least partially within the clutch disk  430  and the tension system being located towards the outer perimeter of the lost motion disk) enables the size of the electronic drive to be reduced. 
     The clutch assembly  412  and the worm gear  410  are rotationally supported on the spindle  406  and secured in place by an E-clip  442 . One or more fasteners  444  may be used to couple the clutch assembly  412 , worm gear  410 , and spindle  406  to the housing  222  (shown in  FIGS.  2 A and  2 B ). In an example, this spindle component assembly may be assembled separately from the rest of the components of the electronic drive  200  (shown in  FIGS.  3 A- 3 C ) so that the tension system can be more easily installed and compressed to pre-load the clutch assembly  412 . This can facilitate more efficiencies in the manufacturing process. 
       FIG.  9    is a front view of the lost motion disk  432  of the clutch assembly  412  (shown in  FIG.  8   ). The spring fingers  438  extend substantially circumferentially along an outer perimeter of the disk  432  and are formed by a slit  446  within the body of the disk  432 . The spring fingers  438  can release from, and subsequently recouple to, the clutch disk  430  (shown in  FIG.  8   ) as described above. As such, the spring fingers  438  can move in a substantially radial direction when the biasing force of the spring fingers  438  are overcome (e.g., overcoming the resilient force of the disk material) to decouple the disk  432  from the clutch disk  430 . The spring fingers  438  include a radially extending detent  448  that is shaped and sized to be received within the notches  440  of the clutch disk  430  (shown in  FIG.  8   ), and when the detent  448  and the notches  440  are engaged, the rotational movement is transferred between the lost motion disk  432  and the clutch disk  430 . In one example, the detent  448  may be formed by two oblique surfaces. 
     In the example, the spring fingers  438  are circumferentially aligned with the lugs  436  and there are two fingers  438  spaced approximately 180° apart from one another. By aligning the lugs  436  and the fingers  438  the release of the lost motion disk  432  more closely corresponds to the driven motion of the clutch assembly  412 . In other examples, the spring fingers  438  may be circumferentially offset from the lugs  436  as required or desired. 
     The materials utilized in the manufacture of the lock assemblies described herein may be those typically utilized for lock manufacture, e.g., zinc, steel, aluminum, brass, stainless steel, etc. Molded plastics, such as PVC, polyethylene, etc., may be utilized for the various components. Material selection for most of the components may be based on the proposed use of the locking system. Appropriate materials may be selected for mounting systems used on particularly heavy panels, as well as on hinges subject to certain environmental conditions (e.g., moisture, corrosive atmospheres, etc.). Additionally, the lock described herein is suitable for use with doors constructed from vinyl plastic, aluminum, wood, composite, or other door materials. 
     Any number of features of the different examples described herein may be combined into one single example and alternate examples having fewer than or more than all the features herein described are possible. It is to be understood that terminology employed herein is used for the purpose of describing particular examples only and is not intended to be limiting. It must be noted that, as used in this specification, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. 
     While there have been described herein what are to be considered exemplary and preferred examples of the present technology, other modifications of the technology will become apparent to those skilled in the art from the teachings herein. The particular methods of manufacture and geometries disclosed herein are exemplary in nature and are not to be considered limiting. It is therefore desired to be secured in the appended claims all such modifications as fall within the spirit and scope of the technology. Accordingly, what is desired to be secured by Letters Patent is the technology as defined and differentiated in the following claims, and all equivalents.