Patent Abstract:
An actuator for an electronic door lock includes a stationary first magnet assembly, a beam, and a second magnet assembly. The first magnet includes at least one magnet stationarily positioned within the electronic door lock. The beam is movable relative to the first magnet assembly to a first position and a second position. The second magnet assembly is connected to the beam and is configured to be magnetically repulsed away from the first magnet assembly. The repulsion of the second magnet assembly maintains the beam in either the first or second position until the beam is selectively actuated therefrom.

Full Description:
BACKGROUND 
     The present invention relates to a door lock, and more particularly to an actuator for an electronic door lock. 
     Electronic door locks typically include a mechanical lock and an electronic control for authorizing the use of the mechanical lock. A portion of the mechanical lock secures the door to the door frame. The electronic control may include, for example, a reader that permits data to be read from a coded medium such as a magnetic card, proximity card, or memory key. When a card or key with valid data is presented to the electronic control, the control permits an outer handle or door knob to operate a shaft of the mechanical lock by actuating a prime mover to either release a latch that was preventing the handle or knob from turning, or engage a clutch that couples a shaft of the handle or knob to the shaft of the mechanical lock. 
     The mechanical lock and electronic control components (including the prime mover and latch/clutch) of electronic door locks are commonly powered by alkaline batteries which typically have a service life of between about two to three years. This limited battery service life necessitates changing the batteries several times over the service life of the door lock; a process that increases the operating costs of businesses which employ the electrical locks. Many electronic locks utilize a piezoelectric bender as the prime mover to actuate the clutch or latch. Electronic door locks used in certain commercial and hospitality applications are commonly cycled between an office or free passage mode (used during the work day or peak traffic periods to permit entry through the door without the user first presenting a card or key to the reader), and a challenge mode which requires the user to present the card or key to the reader to gain entry through the door. To permit unchallenged entry through the door in the office mode, a conventional electronic door lock uses energy from the batteries to activate and maintain the engagement of the piezoelectric bender with the clutch. This energy drain reduces the service life of the batteries. 
     SUMMARY 
     An actuator for an electronic door lock includes a stationary first magnet assembly, a beam, and a second magnet assembly. The first magnet includes at least one magnet stationarily positioned within the electronic door lock. The beam is movable relative to the first magnet assembly to a first position and a second position. The second magnet assembly is connected to the beam and is configured to be magnetically repulsed away from the first magnet assembly. The repulsion of the second magnet assembly maintains the beam in either the first or second position until the beam is selectively actuated therefrom. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view an electronic door lock including a low energy piezoelectric actuator. 
         FIG. 2A  is a perspective view of one embodiment of the actuator and a clutch disposed in a portion of the door lock with the clutch in a locked position. 
         FIG. 2B  is a perspective view of the actuator and clutch of  FIG. 2A  with the clutch in an unlocked position. 
         FIG. 3A  is a schematic end view of one embodiment of magnets used in the actuator. 
         FIG. 3B  is a schematic end view of another embodiment of the magnets used in the actuator. 
         FIG. 4  is a perspective view of another embodiment of the actuator. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  is a schematic view of an electronic door lock  10  including a low energy clutch  12 . The door lock  10  is disposed in a door  14 . The door lock  10  includes a latch mechanism  16 , an outer escutcheon  18 , an inner escutcheon  20 , and an inner rosette  21 . The outer escutcheon  18  includes an outer handle or knob  22  and a reader  24 . The inner rosette  21  connects to the inner handle or knob  26 . The inner escutcheon  20  has a control circuit  28 , and batteries  30 . Additionally, the door lock  10  includes an actuator  31 , a handle shaft  32  and a lock shaft  34 . The latch mechanism  16  includes a body  36  and a bolt and/or latch  38 . 
     The electronic lock  10  extends through the door  14  between an interior side and an outer side thereof. The door  14  can be part of a vehicle or part of a residential/commercial/hospitality structure. The clutch  12 , latch mechanism  16 , outer escutcheon  18 , and inner escutcheon  20 , can be partially housed within a mortise in the door  14 . The electronic lock  10  includes the outer escutcheon  18  which extends from the outer side of the door  14 , and the inner escutcheon  20  and inner rosette  21  which extend from the interior side of the door  14 . 
     The outer escutcheon  18  is adapted with the reader  24  to receive a coded medium such as a magnetic card, proximity card, or memory key. The outer handle  22  rotatably projects from the lower portion of the outer escutcheon  18 . Interfacing a portion of the outer escutcheon  18  on the interior portion of the door  14  is the inner escutcheon  20 . The inner escutcheon  20  houses the control circuit  28  and batteries  30  therein. The inner handle  26  rotatably connects through the rosette  21  to the lock shaft  34  which is rotatably mounted to extend through the rosette  21  into the clutch  12 . In one embodiment, the rosette  21  houses the actuator  31  which selectively connects to the clutch  12 . The actuator  31  is a beam with one or more magnets and can be actuated, for example, by piezoelectric, electrostatics, or electromagnetically. The lock shaft  34  connects to the body  36  of the latch mechanism  16 . The body  36  actuates or allows the latch and/or bolt  38  to be actuated out of a door frame (not shown) when unlocked. When the latch mechanism  16  is locked, the body  36  retains the latch  38  in the door frame. The clutch  12  selectively couples the lock shaft  34  with the handle shaft  32  when actuated by the actuator  31 . The handle shaft  32  is rotatably mounted in the outer escutcheon  18  and extends therethrough to connect with the outer handle  22 . 
     When the electronic lock  10  (and hence the latch mechanism  16 ) is in a locked state, the handle shaft  32  can be rotatably actuated by the user&#39;s depressing or rotating the outer handle  22 . However, the rotation of the handle shaft  32  is independent of the lock shaft  34  which is disposed adjacent to, and is not in contact with, the handle shaft  32 . Thus, the latch mechanism  16  does not respond to the user&#39;s rotation of the outer handle  22  and the electronic lock  10  remains locked. 
     The reader  24  is electrically connected to the control circuit  28  which can be activated to supply power through wiring to the actuator  31  adjacent the clutch  12 . The batteries  30  also provide power for the components of the electronic lock  10  including the reader  24 , control circuit  28 , and can supply power to the clutch  12 . 
     When the control circuit  28  is programmed for an office or free passage mode, the latch mechanism  16  for the electronic door lock  10  enters (and is maintained in) an unlocked state, allowing the user to swing the door  14  open without first having to present a valid key card (or other coded medium) to the reader  24 . More particularly, as the control circuit  28  initially enters the office mode, the control circuit  28  piezoelectrically, electrostatically, or electromagnetically actuates a movable beam of the actuator  31  to move the beam from a first position, in which the beam is disengaged from or does not engage the clutch  12  sufficiently to couple it between the shafts  32  and  34 , to a second position, in which the beam engages and moves the clutch  12  to couple the lock shaft  34  with the handle shaft  32 . The coupling of the shafts  32  and  34  via the clutch  12  allows the shafts  32  and  34  to be rotated together to unlock the latch mechanism  16 . 
     Once in the first or second position, the actuator  31  can be electrically or magnetically deactivated yet the beam can be maintained in either position by one or more magnet(s) which are oriented around the beam and one or more magnet(s) arranged on the beam so as to exert a force (generated by magnetic repulsion of the magnets) on the beam and thereby deflect and hold the beam in the first or second position. In one embodiment, the magnetic repulsion is sufficient to overcome a bias force on the clutch  12  which attempts to disengage the clutch  12  from coupling engagement between the shafts  32  and  34 . In this manner the beam is magnetically maintained in the second engaged position while the electronic door lock  10  is in the office mode or is maintained in the first locked position. 
     For the electronic lock  10  and latch mechanism  16  to enter the unlocked state when the control circuit  28  is programmed for a challenge mode, a valid key card (or other coded medium) must first be presented to the reader  24  by the user. The reader  24  signals the control circuit  28  which electrically or magnetically actuates the beam of the actuator  31  to temporarily move the beam from the first locked position to the second engaged position. In the second engaged position, the beam temporarily engages and moves the clutch  12  between the shafts  32  and  34  to couple the shafts  32  and  34  together. 
     After the user to swings the door  14  open, a sufficient period of time has elapsed since the key card was presented to the reader  24  by the user, or some other condition precedent occurs, the control circuit  28  actuates the beam back to the first locked position from the second engaged position thereby decoupling the shafts  32  and  34  and locking the latch mechanism  16 . In both the office mode and challenge mode, the actuation of the beam to and from the first locked position and second engaged position overcomes the magnetic repulsion holding the beam of the actuator  31  in both positions. 
     Because no energy from the batteries  30  is required to hold the beam in the first position or the second position in either the office mode or the challenge mode, the actuator  31  draws very small amounts of power from the batteries  30 . Human (user) torque can also be used to rotate the handle shaft  32  and lock shaft  34  after the shafts  32  and  34  are coupled by the clutch  12  in addition to (or in place of) a drive assembly powered by the batteries  30 . The reduced draw on the batteries  30  during operation increases the service life of the batteries  30 , and thereby, decreases the operating costs associated with replacement of the batteries  30 . 
     The configuration of the electronic lock shown in  FIG. 1  is exemplary, and therefore, neither the arrangement of the lock components nor the type of components illustrated are intended to be in any way limiting.  FIG. 1  simply illustrates an embodiment of an electronic lock that would benefit from the low energy clutch disclosed herein. In another embodiment, the actuator could be adapted to release a latch that was preventing the outer handle and handle shaft from turning in the second position to allow the electronic door lock to be unlocked and the door opened by the user. 
       FIG. 2A  is a perspective view of one embodiment of the actuator  31  and clutch  12  disposed in the rosette  21  with the clutch  12  in the first locked position.  FIG. 2B  is a view of the actuator  31  and clutch  12  of  FIG. 2A  with the clutch  12  in the second unlocked position. The clutch  12  includes a pawl  40 , a plunger  42 , and a bias spring  44 . The rosette  21  includes a mounting plate  46 . The lock shaft  34  includes a blind hole  48 . The actuator  31  includes a frame  50 , a first magnet  52 , a second magnet  54 , a mounting plate  56 , wiring  58 , the beam  60 , a third magnet  62 , a first linkage  64 , a pivot arm  66 , a pivot pin  68 , and a second linkage  70 . 
     In  FIGS. 2A and 2B , the handle shaft  32  has been removed to better illustrate the components of the clutch  12 . In the embodiment shown, the handle shaft  32  is co-axially aligned with and rotatably mounted adjacent the lock shaft  34 . The handle shaft  32  has a cavity (not shown) which rotatably receives an end portion of the lock shaft  34  therein. The pawl  40  is disposed adjacent an end of the handle shaft  32 . A slot, blind hole or camming surface (not shown) within the cavity in the handle shaft  32  selectively receives the plunger  42  portion of the clutch  12  when the plunger  42  is not engaged by the pawl  40 . The rotatable lock shaft  34  houses the plunger  42  and bias spring  44 . More particularly, the plunger  42  and bias spring  44  are movably received in the blind hole  48  in the lock shaft  34 . The mounting plate  46  surrounds the lock shaft  34  and receives the pawl  40 . The pawl  40  is selectively engaged by the actuator  31  to move within the mounting plate  46  to engage the plunger  42 . 
     The hollow generally rectangular frame  50  of the actuator  31  is mounted to the mounting plate  46  adjacent the handle shaft  32  and lock shaft  34 . Sidewalls of the frame  50  have been removed to illustrate components of the actuator  31 . The first and second magnets  52  and  54  are fixedly connected to the sidewalls (not shown). The mounting plate  56  is connected to a lower end portion of the frame  50 . The mounting plate  56  receives the beam  60 . The frame  50  is adapted to receive wiring  58  which electrically connects to the beam  60  (which can be a piezoelectric, electrostatic, or an electromagnet assembly). The beam  60  extends within the frame  50  and is movable between the first and second magnets  52  and  54 . The third magnet  62  is mounted to the beam  60  adjacent the first and second magnets  52  and  54  such that the third magnet  62  is movable between the first and second magnets  52  and  54  along with the beam  60 . The beam  60  connects to the first linkage  64  which extends generally laterally away from the frame  50  to connect to the pivot arm  66 . The pivot arm  68  rotates about the pivot pin  70  which is secured to the mounting plate  56 . The pivot arm  68  connects to the second linkage  70 . The second linkage  70  selectively engages the pawl  40  portion of the clutch  12  to move the pawl  40  into engagement with the plunger  42 . 
     In  FIG. 2A , the actuator  31  does not engage the pawl  40  portion of the clutch  12 . Therefore, the pawl  40  is biased (by a spring or other means not shown) into engagement with the plunger  42  portion of the clutch  12 . The engagement of the pawl  40  with the plunger  42  overcomes the bias of the bias spring  44  to force the plunger  42  downward into the blind hole  48 . The engagement of the pawl  40  with the plunger  42  also disengages the plunger  42  from the slot or blind hole in the lock shaft  32  (not shown) thereby decoupling the shafts  32  and  34  from one another. 
     As illustrated in  FIG. 2A , the magnetic repulsion of the third magnet  62  from the first and second magnets  52  and  54  deflects and holds the beam  60  in the first position. More particularly, the magnetic repulsion of the third magnet  62  from the first and second magnets  52  and  54  deflects the beam  60  generally away from the lock shaft  34  thereby causing the first linkage  64  to pivot the pivot arm  66  generally toward the frame  50 . With the pivot arm  66  pivoted in this manner, the second linkage  70  is disengaged from (or does not engage the pawl  40  with sufficient force to overcome the bias on the pawl  40 ) the pawl  40  which is biased downward into engagement with the plunger  42 . 
     When current is supplied through the wiring  58  to the beam  60  the beam  60  which is illustrated as a piezoelectric assembly mechanically deflects. The deflection of the beam  60  overcomes the magnetic repulsion of the third magnet  62  from the first and second magnets  52  and  54  and the beam  60  moves between the first and second magnets  52  and  54  from the first position of  FIG. 2A  to the second position illustrated in  FIG. 2B . More specifically, the movement of the beam  60  generally toward the lock shaft  34  moves the first linkage  64  to pivot the pivot arm  66  generally toward the pawl  40 . The rotation of the pivot arm  66  engages the second linkage  70  with the pawl  40  thereby overcoming the bias on the pawl  40  and moving the pawl  40  outward away from the plunger  42 . The outward movement of the pawl  40  away from the plunger  42  allows the bias spring  44  to bias the plunger  42  outward from the lock shaft  34  into the slot or blind hole in the lock shaft  32  (not shown) thereby coupling the shafts  32  and  34  together. In one embodiment, the polarity of the current applied to the beam  60  or electro-magnet assembly (not shown) can be reversed to move the beam  60  back between the first and second magnets  52  and  54  from the second position ( FIG. 2B ) to the first position ( FIG. 2A ). In this manner the movement of the beam  60  from the first position to the second position is reversible to lock and unlock the latch mechanism  16  ( FIG. 1 ). 
     When the beam  60  is in either the first position or the second position (the second position would be utilized if the electronic lock  10  is in the office mode setting), the magnetic repulsion of the third magnet  62  from the first and second magnets  52  and  54  maintains or mechanically stabilizes the beam  60  in the deflected position without current having to be applied from the batteries  30  ( FIG. 1 ). Thus, power need only be drawn from the batteries  30  ( FIG. 1 ) when the beam  60  is actuated from the first position to the second position (or visa versa). The configuration and arrangement of the actuator  31  and clutch  12  shown in  FIGS. 2A and 2B  merely represent one embodiment of these components, therefore, the components shown are exemplary. In another embodiment, the frame of actuator  31  can be generally cylindrical in shape and can be mounted inside the inner door handle, outer door handle, handle shaft, or lock shaft. 
       FIG. 3A  is an end view of the actuator  31  illustrating one arrangement of the magnets  52 ,  54  and  62  including the orientation of poles of each magnet  52 ,  54  and  62 .  FIG. 3A  illustrates the beam  60  magnetically deflected to the first locked position and the second unlocked position (indicated with dashed lines). 
     In one embodiment the actuator  31  includes the hollow generally rectangular frame  50  which connects to the first and second magnets  52  and  54  and extends around the beam  60 . The beam  60  extends through an open end of the frame  50  to connect to the first linkage  64  ( FIGS. 2A and 2B ). A lower end of the frame  50  connects to the mounting plate  56  which receives the beam  60 . The first and second magnets  52  and  54  generally interface one another from opposing sidewalls of the frame  50  and are generally aligned along a mechanical neutral axis N of the beam  60 . More particularly, the portion of the beam  60  which connects to the mounting plate  56  aligns generally with the mechanical neutral axis N. In either the first position or the second position, the beam  60  is deflected along its length such that the portion of the beam  60  which the third magnet  62  is mounted around is disposed at a distance from the neutral axis N. More particularly, the beam  60  is deflected into either the first position or the second position by the magnetic repulsion of the third magnet  62  from the first and second magnets  52  and  54 . When the beam  60  is actuated from the first position to the second position (or visa versa), the beam  60  and third magnet  62  pass through the neutral axis N between the first and second magnets  52  and  54 . 
       FIG. 3A  schematically illustrates one possible arrangement of the magnets  52 ,  54 , and  62  poles used to generate the magnetic repulsion of the third magnet  62  from the first and second magnets  52  and  54 . The arrangement disposes the north pole of the first magnet  52  adjacent the north pole of the third magnet  62  and the south pole of the second magnet  54  adjacent the south pole of the third magnet  62 . This arrangement generates the magnetic repulsion that deflects and holds the beam  60  because the magnets  52 ,  54 , and  62  are dipolar and the first pole of the third magnet  62  has the same polarity as the adjacent-most pole of the first magnet  52  and the second pole of the third magnet  62  has the same polarity as the adjacent-most pole of the second magnet  54 . 
       FIG. 3B  schematically illustrates another possible arrangement of the magnets  52 ,  54 , and  62  poles used to generate the magnetic repulsion of the third magnet  62  from the first and second magnets  52  and  54 . In  FIG. 3B , the third magnet  62  is comprised of two magnets, a fourth magnet  62   a  mounted to the beam  60  adjacent the first magnet  52  and a fifth magnet  62   b  mounted to the beam  60  adjacent the second magnet  54 . The magnets  52 ,  54 ,  62   a , and  62   b  are oriented such that they extend longitudinally into the frame  50 , therefore, only the north poles of each magnet are visible to the observer. The arrangement shown generates magnetic repulsion that deflects and holds the beam  60  because the magnets  52 ,  54 ,  62   a  and  62   b  are oriented such that the first pole (north pole in this embodiment) of the fourth magnet  62   a  has the same polarity as the adjacent most pole (north pole in this instance) of the first magnet  52  and the first pole (north pole in this instance) of the fifth magnet  62   b  has the same polarity as the adjacent most pole (north pole in this instance) of the second magnet  54 . 
       FIG. 4  shows another arrangement of the actuator  31  in either the first position or the second position. The actuator  31  includes a stationary member  72  which extends from the mounting plate  56 . The actuator  31  also includes a first magnet  74  and a second magnet  76  in addition to the beam  60 . 
     The member  72  extends from the mounting plate  56  to cantilever over the neutral axis N of the beam  60 . The first stationary magnet  74  connects to the member  72  and has poles which are co-aligned with the neutral axis N. The beam  60  movably extends from the mounting plate  56 . The second magnet  76  is connected to the end portion of the beam  60  adjacent the cantilevered portion of the member  72  and first magnet  74 . The poles of the second magnet  76  are arranged to generate magnetic repulsion of the second magnet  76  from the first stationary magnet  74 . For example, the arrangement of the magnets  74  and  76  disposes the north pole of the first magnet  74  adjacent the north pole of the second magnet  76 . This arrangement generates the magnetic repulsion that deflects and holds the beam  60  in the first and second position. 
     Additional magnet arrangements that result in magnetic repulsion deflecting and maintaining a beam in desired position(s) are within the spirit and scope of the invention. Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.

Technology Classification (CPC): 8