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PRIORITY CLAIM 
     This application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Application No. 61/508,248, filed Jul. 15, 2011, the disclosure of which is hereby incorporated by reference in their entirety. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to interchangeable core locks and to electronically-controlled interchangeable locks. 
     BACKGROUND OF INVENTION 
     Small format interchangeable core (SFIC) locks are widely known in the industry. The concept allows mechanical cylinders to be removed from lock housings by the use of a specially bitted mechanical control key and re-installed into different housings. This can be done quickly and eliminates the need to have the mechanical cylinders rekeyed or re-pinned. 
     A feature of the mechanical SFIC lock is a control element, such as a control sleeve, that includes features that selectively lock the lock within a housing, such as a radial projection, or lug, that extends into a groove formed on the interior of the locking housing to engage the interchangeable cylinder core into the locking housing and lock the cylinder in place. When a properly bitted control key is inserted into the keyway of the interchangeable core and rotated, the control sleeve is rotated with the plug of the cylinder core into a retracted position to withdraw the projection from the groove and release the interchangeable core from the lock housing, thereby allowing the core to be removed from the lock housing. Keys bitted for normal access at the SFIC lock are able to rotate the cylinder plug and open the lock but are not able to rotate the control sleeve with the plug. 
     When developing an electronic SFIC lock retrofit for existing SFIC housings, a feature must be provided to allow the same function of inserting and removing SFIC cores. That is, a control element and means for actuating the control element must be provided so that the SFIC lock can be locked within and removed from the lock housing. 
     One SFIC electronic cylinder is described in U.S. Pat. No. 6,604,394. The core described in the &#39;394 patent includes a control sleeve that is blocked from retracting by a spring biased blocking pin. Removal of the core requires a specially-shaped control key that has an extension on the key tip that, when the key is inserted into the cylinder, extends into the cylinder and raises the blocking pin out of the path of the control sleeve and allows the control sleeve to rotate in conjunction with the plug of the lock core to a retracted position. Normal access keys lack the extension on the key tip, and thus do not engage the control sleeve blocking pin when used to open the SFIC electronic cylinder. Like the normal access keys, the special control key must be programmed for access to the SFIC electronic cylinder in order to rotate the plug, but the engagement with the control sleeve is entirely a function of the mechanical portion of the key tip. No key programming is provided to differentiate the control key from the normal access key. 
     This mechanical approach to controlling rotation of the control sleeve represents a critical security flaw. Any normal access key programmed to operate the SFIC electronic cylinder could be used, in conjunction with picking tools able to raise the control sleeve blocking pin, to remove the core and leave the door unsecured. While the key and lock audit would capture the opening of the cylinder, there would be no subsequent audit of entries while the cylinder was removed from the door. 
     SUMMARY OF THE INVENTION 
     According to one aspect of the invention an electronic SFIC lock is configured so that the core locking features are electronically controlled, and keys can be electronically programmed to operate either as a normal user key or as a control key able to remove the SFIC cores. Thus, the same key will operate as a normal access key or as a control key, depending on how the key is programmed. 
     Because the control key is specially programmed, an audit event is captured and stored indicating that the core was removed. 
     Aspects of the invention embody a method for the electronic SFIC lock to operate normally in response to the presentation of a user key or to respond to the presentation of the electronic control key to facilitate the removal of the core from the housing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded perspective view of an electronically-controlled removable core lock embodying aspects of the present invention. 
         FIG. 2  is a front-end view of the removable core lock with a locking lug of a control sleeve in a retracted position (key not shown for clarity). 
         FIG. 3  is a bottom perspective view of the lock with the control sleeve retracted (key not shown for clarity). 
         FIG. 4  is a front-end view of the lock with the control sleeve in an extended position. 
         FIG. 5  is a bottom perspective view of the lock with the control sleeve in an extended position. 
         FIG. 6  is a side perspective view of the lock with the shell omitted and showing the control sleeve in the retracted position. 
         FIG. 7  is a side perspective view of the lock with the shell omitted and showing the control sleeve in an extended position. 
         FIG. 8  is a rear perspective view of the lock with the shell and the plug omitted showing the control sleeve in a retracted position and showing the side bar in an unlocked position. 
         FIG. 9  is a rear perspective view with the shell, plug, and side bar omitted and showing the control sleeve in a retracted position. 
         FIG. 10  is a rear perspective view with the shell, plug, and side bar omitted and showing the control sleeve in an extended position. 
         FIG. 11  is a rear perspective view with the shell and plug omitted, showing the control sleeve in an extended position and the side bar in a locked position. 
         FIG. 12  is a rear-end view with the shell, plug, and side bar omitted, showing the control sleeve in a retracted position. 
         FIG. 13  is a rear-end view with the shell, plug, and side bar omitted, showing the control sleeve in an extended position. 
         FIG. 14  is a partial perspective view of a key configured to operable in an electronically-controlled removable core lock embodying aspects of the present invention. 
         FIG. 15  is an end view of the key with the key body omitted from the drawing. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     An electronic SFIC lock embodying aspects of the invention includes a microcontroller and a motor that controls access by controlling operation of the lock. A key provides power and communication with the cylinder. The key and cylinder exchange secure communications as part of the authentication process to determine if the user is allowed access. The motor is coupled to a blocking actuator that controls a side bar that is engageable with a groove formed within the SFIC shell. When the side bar is engaged with the groove, it prevents rotation of the cylinder plug within the shell. When the cylinder core is presented with a properly authenticated key, the motor is activated to move the blocking actuator, so that the side bar can disengage from the groove, and the key can be used to rotate the cylinder plug. 
     In normal operations the motor-controlled blocking actuator and side bar interference are all that are required to allow or prevent the rotation of the cylinder plug to the unlocked position. 
     In accordance with aspects of the invention, the motor provides a secondary function. The secondary function of the motor and actuator allows removal of the cylinder core from the housing based on electronic signals from a properly authenticated control key. 
     In accordance with one embodiment of the lock, when the microcontroller receives the secure authentication message from the electronic control key to request release of the cylinder core from the housing, the microcontroller first causes the motor to drive the blocking actuator in a first direction to release the side bar so that it can be disengaged from the locking groove and thereby allow the user to rotate the cylinder core in the direction of unlock. The microcontroller then activates the motor in such a manner as to couple the control element to the cylinder plug, so that rotation of the plug moves the control element from a first position locking the core with respect to the housing (i.e., a core locking or lock position) to a second position releasing the lock core with respect to the housing (i.e., a core releasing or release position). In one embodiment, the microcontroller reverses the direction of the motor to drive a secondary element of the motor actuator, a control pin actuator, in the opposite direction. The secondary element of the motor actuator pushes down a control pin inside the cylinder plug (and rotatable with the cylinder plug) to extend it outward toward a control pin hole in an outer portion of the control sleeve. When the control pin is engaged with the control sleeve, by rotating the cylinder until the control pin is aligned with the control pin hole, the motor actuator pushes the control pin into the control pin hole, thereby coupling the control sleeve to the plug. The control sleeve can then be rotated, along with the plug, to the retracted position. With the control sleeve refracted, the cylinder core can be removed from the housing. 
       FIG. 1  shows an exploded perspective view of an electronically-controlled removable core lock  50  embodying aspects of the invention. Lock  50  includes a plug  2  disposed within a lower portion of a shell  1 . A printed circuit board (PCB) assembly  10 , which includes the microcontroller, is disposed in a top portion of the plug  2 . The microcontroller of the lock  50  may comprise a microprocessor in communication with memory, such as electronically erasable programmable read only memory (EEPROM), and is associated with functions related to the operation of the lock and a corresponding key, such as, comparing information, executing algorithms to effect operation of the lock, and storing information relating to authorization codes (e.g., control or access credentials), passwords, lock activation events (e.g., audit events, such as entry and core removal), and other data. The microcontroller may also include access control reader that receives signals from a key or other device. The signals may comprise authentication codes (e.g., access and/or control credentials) and may be received either via wires, or other conductors, or wirelessly. 
     The plug  2  includes a hollowed out portion that receives a motor assembly  8 . A plug front  3  is disposed on a front end of the plug  2 , and a contact housing  16 , holding contact elements  12 ,  13 , and  14 , is disposed within the plug front  3  and is attached to the plug front  3 . The plug front  3  is rotationally coupled to the plug  2  by a splined button  46  (see  FIGS. 10 and 12 ) that is pressed into a hole formed in the plug  2 . A drill plate  9  is disposed between the plug front  3  and the motor assembly  8 . A latch pin control collar  18  and a control sleeve  7  are disposed within the shell  1 , and the plug  2  extends through the collar  18  and sleeve  7 . The plug front  3 , motor assembly  8 , collar  18 , control sleeve  7 , and plug  2  are retained within the shell  1  by a plug retainer plate  5  that is secured to the shell  1  by means of screws  15 . 
     The plug  2  is coupled to a door latch or deadbolt mechanism via a cam or a tailpiece (not shown). A side bar  4 , that is radially biased by spring  21 , is disposed within a rear end of the plug  2 . The removable core assembly  50  is secured within a lock housing by a control element that can be selectively moved between a core lock position and a core release position. In one embodiment, the control element comprises the control sleeve  7 , which is electronically controlled in accordance with aspects of the present invention. 
     As shown in  FIGS. 8-13 , the control sleeve  7  includes a locking lug  31  that extends from a control sleeve slot  29  (see  FIG. 1 ) formed in the shell  1 . The removable core assembly  50  is secured within a housing when the control element is in the core lock position, for example, when the control sleeve  7  is in an extended position so that the locking lug  31  of the control sleeve projects from the shell  1  as shown in  FIGS. 4 and 5 . To remove the removable core assembly  50  from the housing, the control element must be moved from its core lock position to its core release position. In the illustrated embodiment, the control sleeve  7  is rotated to withdraw the locking lug  31  into the shell, thereby moving the control sleeve  7  from its core lock position to its core release position, thus permitting the lock assembly  50  to be removed from the housing. 
     An electronic key can be engaged with the contacts  12 ,  13 ,  14  through a key hole  28  formed in a front face of the shell  1 . Locking and unlocking of the lock assembly  50  is effected by controlling the side bar  4  disposed within the plug  2 . As shown in  FIGS. 8 and 11 , which are rear perspective views of the lock assembly  50  with the shell  1  and plug  2  omitted, the side bar  4  is arranged within the plug  2  in a generally radial orientation with the spring  21  urging side bar tip  40  radially outwardly into engagement with a groove (not shown) formed within the shell  1 . As shown in  FIG. 11 , when in the locked condition, inward radial movement of the side bar  4  is prevented by a blocking pin  20  that is urged by blocking pin spring  19  into the blocking position shown in  FIG. 11 . With the side bar extended so that the side bar tip  40  extends within the groove of the shell  1 , rotation of the plug  2  is prevented. When a properly programmed key is inserted into the key hole  28  to engage the contacts  12 ,  13 ,  14 , a motor assembly  8  that is controlled by the PCB assembly  10  causes a blocking pin actuator  36  to rotate from a first position in  FIG. 11  to a second position shown in  FIG. 8 . In the first position shown in  FIG. 11 , the blocking pin actuator  36  allows the blocking pin  20  to extend by the force of blocking pin spring  19  into a position that blocks radial inward movement of the side bar  4 . When the motor assembly  8  rotates the blocking pin actuator  36  (counter-clockwise in the illustrated embodiment), the blocking pin actuator  36  contacts the blocking pin  20  and pushes it against the spring  19  to the position shown in  FIG. 8 . With the blocking pin  20  pushed to the second position shown in  FIG. 8 , the side bar  4  is allowed to move radially inwardly as torque is applied to the plug  2  to force the plug tip  40  from the internal groove within the shell  1 , thereby allowing the plug  2  to be rotated. 
     Splined button  46  functions as an over-torque feature. If an unauthorized key or other instrument is inserted into the key hole  28  and twisted in an attempt to overcome the side bar  4 , the button  46  will shear, thereby allowing the plug front  3  to rotate independently of the plug  2 . With the plug front able to rotate independently of the plug  2 , torque applied to the plug front  3  by an unauthorized key will not be transmitted to the plug  2 . 
     The side bar  4 , blocking pin  20 , motor  8 , and blocking pin actuator  36 —along with the microprocessor—comprise components of an exemplary embodiment of an electronically-controlled plug locking mechanism configured to selectively permit or block rotation of the plug within the shell. 
     As noted, the illustrated lock assembly  50  is retained within a housing by means of the control sleeve  7  and the locking lug  31  of the control sleeve extending out of the shell  1  through the opening  29 . To remove the lock assembly  50  from the housing, the control sleeve  7  must be rotated to retract the locking lug  31  into the shell  1 . The control sleeve  7  is rotationally biased into the extended position by means of a bullet-nose pin  22  urged by a spring  23  against an angled camming recess  35  formed in the top rear surface of the control sleeve  7 . The bullet-nose pin  22  is urged axially forwardly by the spring  23  and, by engagement with the camming recess  35 , urges the control sleeve clockwise, as shown in  FIGS. 9-13 , to urge the locking lug  31  into the extended, locked position shown in  FIGS. 11 and 13 . 
     The lock assembly  50  may be removed from a housing using a properly programmed control key. When a properly programmed and authenticated control key is presented, first, the motor assembly  8  rotates the locking pin actuator  36  into contact with the blocking pin  20 , thereby allowing the side bar  4  to move axially inwardly into a retracted position as torque is applied to the plug  2 , thereby permitting the plug to be rotated. After the locking pin actuator  36  rotates into contact with the locking pin  20 , the plug  2  is partially rotated to drive the side bar tip  40  out of the internal groove formed in the shell  1  and push the side bar  4  down. The motor assembly  8  then reverses direction, and rotates a control pin actuator  37  into contact with a control pin  6  that is biased radially inwardly by a telescoping spring  17  disposed between a shoulder of the pin  6  and a washer  11  (see  FIGS. 9-13 ). Although the reverse rotation of the motor  8  also moves the blocking pin actuator  36  out of contact with the blocking pin  20 , the blocking pin  20  is prevented from returning to its blocking position by a side bar leg  44  extending from the bottom of the side bar  4  (see  FIG. 8 ). Rotation of the control pin actuator  37  pushes the control pin  6  radially outwardly, so that the control pin, which is rotatable with the plug  2 , will engage a control pin hole  32  formed in the control sleeve  7  when the plug  2  is rotated to align the control pin  6  with the control pin hole  32 . With the control pin  6  engaged into the hole  32  of the control sleeve  7 , the control sleeve  7  becomes coupled to the plug  2 , so that rotation of the plug  2  will also rotate the control sleeve  7 , thereby permitting the locking lug  31  to be retracted. The amount of rotation of the control sleeve  7  is limited by means of a hard stop projection  33  extending from the control sleeve  7  and engaged with a rectangular cut-out  30  formed adjacent the control sleeve slot  29  in the shell  1 . This is illustrated by comparison of  FIGS. 3 and 5 . 
     The motor  8 , control pin  6 , control pin actuator  37 , and the control pin hole  32 —along with the microprocessor—comprise components of an exemplary embodiment of an electronically-controlled control element coupling mechanism configured to electronically control coupling of the control element, such as control sleeve  7 , to the plug  2 . 
     In one embodiment, the lock assembly  50  includes a secondary feature for blocking rotation of the control sleeve  7 , which is known as a “dead-latch feature.” This feature comprises the latch pin control collar  18  having a latch pin recess, or relief area,  38  formed therein and a latch pin  24  that is biased radially inwardly by a spring  26 . The latch pin  24  and spring  26  are is secured within the shell  1  by a set screw  25 . The latch pin  24  includes a blocking collar  41  that, when in the position shown in  FIG. 7 , engages a blocking lug  34  extending from the control sleeve  7 , thereby preventing control sleeve  7  from being rotated into a retracted position. Rotation of the collar  18  into the position shown in  FIG. 6  causes the latch pin tip  42  of the latch pin  24  to extend into the latch pin recess  38  of the collar  18 , as urged by the spring  26 . With the latch pin  24  moved into this second position, as shown in  FIG. 6 , the blocking lug  34  of the control sleeve  7  is no longer engaged with the blocking collar  41  of the latch pin  24 , and the control sleeve  7  is thereby allowed to rotate into a retracted position. 
     The method described above to retract the control sleeve  7  and remove the core assembly  50  from the housing requires the user to initially rotate the cylinder plug  2  partially toward the unlock position. This operation rotates the latch pin control collar  18 , by means of the plug  2  engaging radial projections  39  (see  FIGS. 10 ,  12 ,  13 ) projecting radially inwardly from the inner circumference of the collar  18 , so that the spring loaded latch pin  24  extends into the relief area  38  of the collar  18 , thereby moving the blocking collar  41  on the latch pin  24  out of the path of the blocking lug  34  on the control sleeve  7 . This feature releases the control sleeve  7  to allow it to rotate with the plug  2  once the control pin  6  is engaged in the control pin hole  32  in the control sleeve  7 , as described previously. 
     The operation is only momentary. When power is lost by removing the key, the control pin actuator  37  resets and allows the control pin  6  to be reset by its spring  17  back inside the plug  2 , and the latch pin  24  is reset by its spring  26  after collar  18  is rotated back to the position of  FIG. 7 , to prevent rotation of the control sleeve  7 . 
     The latch pin  24  serves as a deadlatch security feature of the plug  2  to prevent manipulation of the control sleeve  7  by applying direct pressure to the control sleeve  7  and retracting it. 
     A key  60  configured for use with the lock assembly  50  is shown in  FIGS. 14 and 15 . The key  60  includes a body  62  and a keyway projection  66  (the key body  62  is omitted from  FIG. 15 ). The keyway projection  66  is configured to be inserted into the key hole  28  and defines an annular closed structure having an exterior shape that conforms to the shape of the key hole  28  and an interior shape that conforms to corresponding structure in the plug front  3 . The key  60  further includes three pins, or contact elements,  64  configured to engage the contacts  12 ,  13 ,  14  of the lock  50 . 
     The key includes a microcontroller disposed within the body  62 . The microcontroller of the key  60  may comprise a microprocessor in communication with memory, such as electronically erasable programmable read only memory (EEPROM) and is associated with functions related to the operation of the lock  50  and key  60 , such as, comparing information, executing algorithms to effect operation of the lock, and storing information relating to authorization codes (e.g., control or access credentials), passwords, lock activation events (e.g., audit events, such as entry and core removal), and other data. The microcontroller of the key  60  communicates with the microcontroller of the lock  50  via contact between the pins  64  of the key  60  with the contacts  12 ,  13 ,  14  of the lock  50 . During such communication, data and power are exchanged between the key  60  and lock  50 . 
     A key  60  and lock  50  have a unique authorization, or identification, codes programmed in the memories of the respective microcontrollers. When the key projection  66  is inserted into the key hole  28 , the key microcontroller sends an authentication code to the lock microcontroller, and the lock microcontroller performs a comparison to determine if the key  60  is authorized to open the lock  50 . If the key  60  is authorized to open the lock  50  (i.e., the key presents a valid access credential), the lock microcontroller and/or the key microcontroller sends a signal to the motor assembly  8  to actuate the blocking pin actuator  36  to move the blocking pin  20  (as described above), thereby allowing the side bar  4  to move down when torque is applied to the plug  2 , and thus the lock  50  can be opened. 
     The key  60  may include an indicator such as a light (LED) and/or beeper that indicates the status of the key. For example, the indicator may shine green if the key is authorized to open a lock and red if the key is not authorized to open a lock. 
     The key  60  may be programmed to implement a hierarchical lock system, where some keys are programmed to open certain locks—perhaps only one lock—and other keys may be programmed as master keys, thereby able to open several—perhaps all—locks in the system. 
     The key  60  may also be programmed as a control key able to remove a removable core from its housing. When the key projection  66  of a key  60  programmed as a control key is inserted into the key hole  28 , the key microcontroller sends an authentication code to the lock microcontroller. The lock microcontroller confirms that the key is an authorized control key (i.e., the key presents a valid control credential), and the lock microcontroller and/or the key microcontroller sends a signal to the motor assembly  8  to actuate the blocking pin actuator  36  to move the blocking pin  20  (as described above), thereby allowing the side bar  4  to move down when torque is applied to the plug  2 , and thus the lock  50  can be opened. After the plug  2  has been partially rotated, the lock microcontroller and/or the key microcontroller sends a signal to the motor assembly  8  to actuate the control pin actuator  37  to apply an outward axial force to the control pin  6 . A signal, such as a flashing LED on the key  60 , may be provided to indicate to the user that the control pin actuator  37  has been activated to engage the control pin  6 . The plug is then rotated in the opposite direction to align the control pin  6  with the control pin hole  32  to couple the control sleeve  7  to the plug  2 . The plug  2  is then rotated back in the first direction to retract the sleeve  7 , and the lock assembly  50  can be removed from its housing. 
     While the present invention has been described and shown in considerable detail with reference to certain illustrative embodiments, including various combinations and sub-combinations of features, those skilled in the art will readily appreciate other embodiments and variations and modifications thereof as encompassed within the scope of the present invention. Moreover, the descriptions of such embodiments, combinations, and sub-combinations is not intended to convey that the inventions requires features or combinations of features other than those expressly recited in the claims. Accordingly, the present invention is deemed to include all modifications and variations encompassed within the spirit and scope of the following appended claims.

Summary:
An electronic small format interchangeable core (“SFIC”) lock is configured so that core locking features are electronically controlled, and keys can be electronically programmed to operate either as a normal user key able to open the lock or as a control key able to open the lock and to remove the SFIC cores. The same key will operate as a normal access key or as a control key, depending on how the key is programmed.