Patent Publication Number: US-8117876-B2

Title: Programmable lock cylinder assembly

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to lock cylinder assemblies. More particularly, the present invention relates to a lock cylinder assembly that may be reprogrammed without removing the cylinder plug. 
     When reprogramming a lock cylinder using a traditional cylinder design, the user is required to remove the cylinder plug from the cylinder body and replace the appropriate pins so that a new key can be used to unlock the cylinder. This typically requires the user to remove the cylinder mechanism from the lockset and then disassemble the cylinder to some degree to remove the plug and replace the pins. This requires a working knowledge of the lockset and cylinder mechanism and is usually only performed by locksmiths or trained professionals. Additionally, the process usually employs special tools and requires the user to have access to pinning kits to interchange pins and replace components that can get lost or damaged in the reprogramming process. 
     SUMMARY OF THE INVENTION 
     In at least one aspect, the present invention provides a programmable lock cylinder assembly comprising: a lock housing having a body defining a tubular opening and a cylinder plug having a body mounted for rotation within the tubular opening. The cylinder plug includes a keyway extending therein. A set of rack pins are positioned in the cylinder plug and moveable between a locked position wherein the cylinder plug is rotationally locked relative to the housing and an unlocked position wherein the cylinder plug is rotational relative to the housing. A set of tongue pins are positioned in the cylinder plug and extend across the keyway. Each tongue pin is selectively engagable with a respective rack pin. A re-combinating member is engaged with the tongue pins and moveable between a first position wherein the tongue pins are engaged with the rack pins and a second position wherein the tongue pins are disengaged from the rack pins. A reset actuator is positioned within the cylinder plug and moveable between an engaged position wherein the re-combinating member position is locked relative to the cylinder plug and a non-engaged position wherein the re-combinating member position is moveable relative to the cylinder plug. 
     In another aspect, the present invention includes at least a first subset of rack pins and a second subset of rack pins. The first subset of rack pins have at least two operable bitting configurations and the second subset of rack pins have a different bitting configuration such that the lock cylinder assembly is master keyable. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded isometric view of a programmable lock cylinder assembly according to a first embodiment of the invention. 
         FIG. 2  is an assembled isometric view of the programmable lock cylinder assembly of  FIG. 1  with a key inserted therein. 
         FIG. 3  is an isometric view similar to  FIG. 2  with the lock housing removed and the sidebar shown translucently. 
         FIG. 4  is a right-side isometric view of the lock cylinder plug with the re-combinating sidebar shown translucently. 
         FIG. 5  is a left-side isometric view of the lock cylinder plug with the locking sidebar removed. 
         FIG. 6  is a top isometric view of the lock cylinder plug with the top cover removed. 
         FIG. 7  is a cross-sectional view along line  7 - 7  in  FIG. 2  with the lock cylinder assembly in a home position. 
         FIG. 8  is an isometric view of the lock cylinder assembly as shown in  FIG. 7 . 
         FIG. 9  is an isometric view of a rack pin in accordance with a first embodiment of the invention. 
         FIG. 10  is a cross-sectional view similar to  FIG. 7  with a key inserted into the lock cylinder assembly. 
         FIG. 11  is an isometric view of the lock cylinder assembly as shown in  FIG. 10 . 
         FIG. 12  is a cross-sectional view similar to  FIG. 7  with a key inserted into the lock cylinder assembly and the cylinder plug rotated to an unlock position. 
         FIG. 13  is an isometric view of the lock cylinder assembly as shown in  FIG. 12 . 
         FIG. 14  is a cross-sectional view illustrating the relative position of a user key to the reset actuator during normal operation. 
         FIG. 15  is a cross-sectional view similar to  FIG. 14  illustrating the engagement of a reset key with the reset actuator. 
         FIG. 16  is a side elevational view of a key illustrating both a user key configuration and a reset key configuration. 
         FIG. 17  is a top down cross-sectional view of the lock cylinder assembly with a reset key positioned in the keyway and the reset actuator moved to a reset position. 
         FIG. 18  is a cross-sectional view illustrating a reset key engaging the reset actuator. 
         FIG. 19  is a cross-sectional view similar to  FIG. 7  with a current reset key inserted into the lock cylinder assembly. 
         FIG. 20  is a cross-sectional view similar to  FIG. 19  with the current reset key inserted into the lock cylinder assembly and the cylinder plug initially rotated. 
         FIG. 21  is a cross-sectional view similar to  FIG. 19  with the reset key inserted into the lock cylinder assembly and the cylinder plug rotated to a reset position. 
         FIG. 22  is an isometric view of the lock cylinder assembly as shown in  FIG. 21 . 
         FIG. 23  is a cross-sectional view similar to  FIG. 21  with the reset key removed. 
         FIG. 24  is a top down cross-sectional view similar to  FIG. 17  with the reset key removed and the reset actuator moved to a reset locked position. 
         FIG. 25  is a cross-sectional view similar to  FIG. 21  with a new reset key inserted into the lock cylinder assembly. 
         FIG. 26  is a top down cross-sectional view similar to  FIG. 17  with the new reset key inserted and the reset actuator moved to the reset position. 
         FIG. 27  is a cross-sectional view similar to  FIG. 25  illustrating rotation of cylinder plug with the new reset key inserted therein from the reset position to the home position. 
         FIG. 28  is a cross-sectional view similar to  FIG. 27  illustrating the reprogrammed cylinder plug in the home position with the new reset key removed. 
         FIG. 29  is an exploded isometric view of a programmable lock cylinder assembly according to another embodiment of the invention. 
         FIG. 30  is an assembled isometric view of the programmable lock cylinder assembly of  FIG. 29  with a key inserted therein. 
         FIG. 31  is an isometric view similar to  FIG. 30  with the lock housing removed. 
         FIG. 32  is a left, top isometric view of the lock cylinder plug with the housing removed. 
         FIG. 33  is an isometric view of a key with a re-combinating sidebar and tongue pins of the present embodiment positioned relative thereto. 
         FIG. 34  is a left-side isometric view of the lock cylinder. 
         FIG. 35  is a left-side isometric view of the lock cylinder plug with the locking sidebar removed. 
         FIG. 36  is a right-side isometric view of the lock cylinder plug with the re-combinating sidebar removed. 
         FIG. 37  is a cross-sectional view of the lock cylinder assembly of  FIG. 29  in a home position. 
         FIG. 38  is an isometric view of the lock cylinder assembly as shown in  FIG. 37 . 
         FIG. 39  is a cross-sectional view similar to  FIG. 37  with a key inserted into the lock cylinder assembly. 
         FIG. 40  is an isometric view of the lock cylinder assembly as shown in  FIG. 39 . 
         FIG. 41  is a cross-sectional view similar to  FIG. 37  with a key inserted into the lock cylinder assembly and the cylinder plug rotated to an unlock position. 
         FIG. 42  is an isometric view of the lock cylinder assembly as shown in  FIG. 41 . 
         FIG. 43  is a cross-sectional view similar to  FIG. 39  with a key inserted into the lock cylinder assembly. 
         FIG. 44  is a cross-sectional view similar to  FIG. 34  with a reset key inserted into the lock cylinder assembly. 
         FIG. 45  is an isometric view of a reset key. 
         FIG. 46  is an end elevation view of the reset key of  FIG. 45 . 
         FIG. 47  is an end elevation view similar to  FIG. 46  and illustrating the configuration of a user key. 
         FIG. 48  is a cross-sectional view similar to  FIG. 44  with the current reset key inserted into the lock cylinder assembly and the cylinder plug rotated to a reset position. 
         FIG. 49  is a cross-sectional view similar to  FIG. 48  with the reset key removed. 
         FIG. 50  is a top down cross-sectional view of the lock cylinder assembly with a reset key positioned in the keyway and the reset actuator moved to a reset position. 
         FIG. 51  is an end view of the lock cylinder assembly of  FIG. 50 . 
         FIG. 52  is a cross-sectional view similar to  FIG. 48  with a new reset key inserted into the lock cylinder assembly. 
         FIG. 53  is a top down cross-sectional view similar to  FIG. 51  with the new reset key inserted and the reset actuator moved from the locked reset position. 
         FIG. 54  is a cross-sectional view similar to  FIG. 52  illustrating rotation of cylinder plug with the new reset key inserted therein from the reset position toward the home position. 
         FIG. 55  is a cross-sectional view similar to  FIG. 54  illustrating the reprogrammed cylinder plug in the home position with the new reset key removed. 
         FIG. 56  is an isometric view of a locking sidebar in accordance with an alternative embodiment of the invention. 
         FIGS. 57 and 58  are isometric views of rack pins in accordance with alternative embodiments of the invention. 
         FIGS. 59-63  are isometric views illustrating engagement of the locking sidebar of  FIG. 56  with the rack pins of  FIGS. 57 and 58  in various positions. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Although the invention is illustrated and described herein with reference to specific embodiments, the invention is not intended to be limited to the details shown. Rather, various modifications may be made in the details within the scope and range of equivalents of the claims and without departing from the invention. 
     A programmable lock cylinder assembly  10  in accordance with a first embodiment of the invention is illustrated and described with reference to  FIGS. 1-28 . Referring to  FIGS. 1-9 , the programmable lock assembly  10  generally comprises a lock housing  20  and a cylinder plug  40 . The lock housing  20  includes a body  22  defining a generally tubular opening  24  extending the length thereof. The tubular opening  24  is configured to receive the cylindrical body  42  of the cylinder plug  40  and may include a shoulder  26  about the opening  24  which engages a flange  44  on one end of the cylinder plug  40 . Referring to  FIG. 2 , the cylinder plug  40  preferably extends out the opposite end of the housing  20  and is configured for connection to an output mechanism (not shown) for transmitting force from the cylinder plug  40  to one or more elements connected to the lock cylinder assembly  10 . The output mechanism can take a number of different forms, including without limitation, a lever, drive shaft, coupling, cam, or other element mounted to the lock cylinder assembly  10 . The present lock cylinder assembly may be utilized in any desired application. In the illustrated embodiment, a snap ring  30  engages a groove  46  in the cylinder body  42  to retain the lock cylinder assembly  10  in the assembled state illustrated in  FIG. 2 . 
     Referring to  FIGS. 1 and 7 , the housing body  22  includes a pair of tapered groove  25  and  27  extending along the inside surface of the opening  24 . As explained in greater detail hereinafter, a sidebar  80  extends from the cylinder plug  40  and engages the tapered groove  25  to maintain the cylinder plug  40  rotationally locked relative to the housing  20  unless a proper key is positioned in the keyway  39  of the cylinder plug  40 . The tapered groove  27  facilitates reprogramming of the lock cylinder assembly  10 , as described in more detail hereinafter. 
     Referring to  FIGS. 1 and 8 , the housing body  22  may include a plurality of through bores  29  which align with rack pin bores  41  of the cylinder plug  40  when the cylinder plug  40  is positioned in a home position. The through bores  29  are configured to receive a portion of an associated rack pin  60 , as described hereinafter, to further maintain the cylinder plug  40  rotationally locked relative to the housing  20  unless a proper key is positioned in the keyway  39  of the cylinder plug  40 . Desirably, through bores  29  are provided on the upper and lower surfaces, in the illustrated orientation, such that the lock cylinder assembly  10  may be provided with upper and lower rack pins, if desired, for operation with a key having teeth on its upper and lower surfaces. 
     Referring to  FIGS. 1 ,  3  and  5 - 8 , the rack pin bores  41  extend substantially parallel to the keyway  39  of the cylinder plug  40 . Each rack pin bore  41  is configured to receive and guide the axial movement of a rack pin  60 . Each rack pin bore  41  desirably extends completely through the cylinder plug  40  such that the associated rack pin  60  may be configured to be moved upward or downward into engagement with an associated through bore  29 , however, such is not required. Alternatively, the rack pin bores  41  may only extend from one surface of the cylinder plug body  42 , or may even be completely internal within the cylinder plug body  42  such that the rack pins do not extend from the cylinder plug  40 . 
     Referring to  FIGS. 1 ,  3 ,  5  and  7 , a sidebar opening  48  extends through a side surface of the cylinder body  42  in communication with the rack pin bores  41 . The sidebar opening  48  is sized to receive a sidebar  80  such that a tapered portion  84  of the sidebar  80  is radially extendable from the cylinder plug  40 . In the home position illustrated in  FIG. 7 , the tapered portion  84  extends from the cylinder plug  40  and is engaged in the tapered groove  25  to rotationally lock the cylinder plug  40  relative to the housing  20 . One or more springs  86  are positioned between a rail portion  82  of the sidebar  80  and internal portions  49  of the cylinder body  42  to bias the sidebar radially outward. 
     The sidebar  80  is prevented from being moved radially inward, and thereby unlocking the lock, by the rack pins  60  unless a proper key is positioned in the keyway  39 . An exemplary rack pin  60  is illustrated in  FIG. 9 . The exemplary rack pin  60  includes an elongate body  62  generally having a width slightly less than the width of an associated rack pin bore  41  such that the rack pin  60  is axially movable therein. In the present embodiment, an end  68  of the rack pin  60  has a reduced width and is configured to be received in a corresponding housing through bore  29 . The rack pin  60  includes a plurality of engagement passages  66  which facilitate programming of the lock cylinder assembly  10  as will be described in more detail hereinafter. 
     The rack pin  60  also includes a sidebar notch  64  configured to receive the rail portion  82  of the sidebar  80 . As illustrated in  FIG. 7 , the rack pin body  62  generally has a thickness such that the rack pin body  62  contacts the sidebar rail portion  82  and prevents radial movement of the sidebar  80 . When a proper key  150  is inserted in the keyway  39 , the rack pin  60  is moved axially, as described below, such that the sidebar notch  64  is aligned with the sidebar rail portion  82  as shown in  FIG. 10 . With each rack pin  60  so aligned, the sidebar  80  is movable radially inward. In the present embodiment, the sidebar  80  does not automatically move radially inward, but instead is biased radially outward as explained above. Referring to  FIG. 12 , with the proper key  150  inserted, the rack pins  60  are disengaged from the through bores  29  and the sidebar notches  64  are properly aligned, such that rotation of the key  150  causes the tapered portion  84  of the sidebar  80  to ride up the tapered groove  25  as the sidebar rail portion  82  is received in the notches  64 . The lock cylinder assembly  10  is in an unlocked condition such that the cylinder plug  40  is rotatable relative to the housing  20 . Rotation of the cylinder plug  40  actuates the output mechanism. When the key  150  is rotated back to the home position, the sidebar  80  automatically extends radially into engagement with the tapered groove  25 . When the key  150  is removed, the rack pins  60  return to the home position wherein the notch  64  is no longer aligned with the sidebar rail portion  82  and the sidebar  80  is prevented from moving radially inward. 
     To facilitate axial movement of the rack pins  60  in response to an inserted key, each rack pin  60  is associated with a tongue pin  90  which extends perpendicular to the rack pin  60  across the keyway  39 . Each tongue pin  90  includes a tongue  92  that is selectively engagable with one of the engagement passages  66  of the rack pin  60  through an opening  65  in the back of the rack pin  60  (see  FIGS. 8-10 ). In the present embodiment, the engagement passages  66  have a serrated configuration and the tongues  92  have a corresponding inverted triangular configuration, however, other complementary configurations may also be utilized. 
     In the present embodiment, a spring  78  or the like extends between a top cover  70  and the respective tongue pin  90  to bias the tongue pin  90  downward. When the tongue pin  90  is engaged with a corresponding rack pin  60 , the spring  78  thereby biases the rack pin  60  toward the locked position wherein the rack pin end  68  extends into the housing though bore  29  and the notch  64  is not aligned with the sidebar rail portion  82 . The present top cover  70  includes an inward spring mount  74  depending from its body  72  for each spring  78 . As shown in  FIG. 6 , the cylinder body  42  desirably includes a spring bore  43  for each spring  78  and mount  74  and a channel  45  configured to receive the top cover body  72 . The spring bores  43  may be formed integrally with the rack pin bores  41  as illustrated. The top cover  70  also includes a depending portion  76  configured to cover and retain a reset actuator  120  positioned within a cavity  47  of the cylinder body  42 . 
     In the present embodiment, a re-combinating sidebar  100  is utilized to control the selective engagement between the tongue  92  and the engagement passage  66 , as described in more detail below. Referring to  FIGS. 1 ,  4 ,  6  and  7 , the re-combinating sidebar  100  includes a plurality of shaft portions  102 , each configured to be received in an alignment notch  94  of a corresponding tongue pin  90 . A tapered bar  104  extends perpendicular from the shaft portions  102  and is connected thereto by bridging members  106 . The cylinder body  42  includes a plurality of vertical slots  51 , each configured to receive a corresponding shaft portion  102  with a tongue pin  90  engaged therewith. Each vertical slot  51  terminates in a horizontal slot  53  configured to receive a corresponding bridging member  106  and thereby guide radial movement of the re-combinating sidebar  100 . A horizontal opening  50  extends through the side of the cylinder body  42  and is in communication with the vertical slots  51  such that the tapered bar  104  may extend radially outwardly from the cylinder plug  40 . A plurality of springs  108  or the like are positioned between the cylinder body  42  and the tapered bar  104  such that the re-combinating sidebar  100  is biased radially outward. 
     Referring to  FIG. 7 , during normal operation, the re-combinating sidebar  100  is maintained in a radially inward position such that each tongue  92  of the tongue pins  90  remains engaged with the intended engagement passage  66  of the corresponding rack pin  60 . With reference to  FIGS. 1 ,  6 ,  17  and  18 , a reset actuator  120  is engagable between the cylinder body  42  and the re-combinating sidebar  100  to maintain the re-combinating sidebar  100  in this radially inward, normal operation mode. The reset actuator  120  includes an actuator body  122  with a reset contact  124  depending therefrom. A front face of the actuator body  122  includes two bores  126  and  128 . Each bore  126 ,  128  is configured to receive a post  103  extending rearward from rearward most shaft portion  102 A (see  FIG. 17 ). In the normal operating mode, the post  103  is received in inward bore  126 , as shown in phantom in  FIG. 6 , and thereby maintains the re-combinating sidebar  100  in the radially inward, normal operating position. A spring  130  or the like engages a mount  132  on the rear side of the actuator body  122  and biases the reset actuator  120  toward the re-combinating sidebar  100 , thereby maintaining the post  103  engaged within the bore  126  unless an proper reset key  150 ′ is positioned in the keyway  39 . 
     Referring to  FIGS. 14-16 , the present embodiment of the invention utilizes two distinct types of keys, namely a user key  150  and a reset key  150 ′. Both keys  150 ,  150 ′ include a plurality of teeth and notches  152 , but the reset key  150 ′ includes a protruding tip  154 ′ compared to the tapered tip  154  of the user key  150 . As shown in  FIG. 14 , during normal operation, a user inserts a user key  150  and the tapered tip  154  remains clear of the actuator reset contact  124 . The actuator  120  remains biased by the spring  130  toward the re-combinating sidebar  100 , thereby maintaining the post  103  engaged within the bore  126 . As such, the re-combinating sidebar  100  is maintained in the inward position and each tongue  92  remains engaged with the previously programmed engagement passage  66 . A user can insert a proper user key  150  which will engage the tongue pins  90  which in turn will move the rack pins  60  axially such that the rack pin notches  64  are aligned with the sidebar rail portion  82 . The lock cylinder assembly  10  may be utilized in a normal manner as described above. 
     If a user desires to reprogram the lock cylinder assembly  10  without disassembling the lock cylinder assembly, the user may insert a proper reset key  150 ′. Insertion of the reset key  150 ′ will cause the protruding tip  154 ′ to engage the actuator reset contact  124  and thereby disengage the post  103  from the bore  126  as illustrated in  FIGS. 15 and 17 . As explained below, reprogramming of the lock cylinder assembly  10  requires rotation of the cylinder plug  40 . As such, inserting an improper key, even if such engages the actuator reset contact  124 , will not allow reprogramming because the improper key will not properly move the rack pins  60  and the cylinder plug  40  will not be rotatable. 
     Having generally described the components of the lock cylinder assembly  10 , reprogramming thereof will now be described with reference to  FIGS. 15-28 . To reprogram the lock cylinder assembly  10 , the user inserts a current reset key  150 A′ into the keyway as illustrated in  FIGS. 15-19 . By “current”, it is meant that the reset key  150 A′ has a tooth and notch  152  configuration which matches the currently programmed configuration of the lock cylinder assembly  10 . When the current reset key  150 A′ is inserted, the key  150 A′ engages each of the tongue pins  90  and moves the respective rack pins  60  to the unlock position shown in  FIG. 19  wherein each notch  64  is aligned with the sidebar rail portion  82 . The protruding tip  154 ′ of current reset key  150 A′ also engages the actuator reset contact  124  and thereby disengages the reset actuator  120  from the post  103 . Even though the reset actuator  120  is disengaged, the re-combinating sidebar  100  remains inward, and thereby maintains each tongue  92  engaged with the respective engagement passage  66 , because the tapered bar  104  is in contact with the inside surface of the housing opening  24 . 
     The current reset key  150 A′ is then rotated in the direction of arrow A in  FIG. 20 . While clockwise rotation is illustrated in the present embodiment, the invention is not limited to such. For example, the tapered groove  27  may be positioned in the upper right quadrant of the housing body  22 , in which case the plug cylinder  40  would be rotated counter-clockwise for reprogramming, or in any other desired position. As with normal operation, the sidebar tapered portion  84  rides up the tapered groove  25  as the sidebar rail portion  82  is received in the notches  64 . Rotation of the key and cylinder plug  40  in the direction of arrow B in  FIG. 21  is continued until the tapered bar  104  is aligned with the tapered groove  27  in the housing  20 . The springs  108  bias the re-combinating sidebar  100  radially outward as the tapered bar  84  enters the tapered groove  27 . As the re-combinating sidebar  100  moves radially outward, each tongue pin  90  is also moved in the direction of arrow C in  FIG. 21  such that the tongues  92  disengage from the respective engagement passages  66 . The rack pins  60  stay aligned with the sidebar  80  based on the engagement of the rail portion  82  in each of the notches  64 . 
     Referring to  FIGS. 23 and 24 , the current reset key  150 A′ is removed whereby the top springs  78  bias the tongue pins  90  to a lower most position wherein the tongues  92  are not aligned with any of the engagement passages  66 . Additionally, when the current reset key  150 A′ is removed, the actuator reset contact  124  is no longer engaged and the spring  130  biases the reset actuator  120  toward the re-combinating sidebar  100 . With the re-combinating sidebar  100  in the outward reprogram position, the post  103  engages in the outer bore  128 , thereby locking the re-combinating sidebar  100  in such outward reprogram position. This prevents a user from insert a regular user key (non-reset key) and trying to return the cylinder plug  40  to the home position. Additionally, because the tongues  92  do not align with any engagement passages, a user would not be able to insert an object into the keyway to try to bypass the reset actuator  120  as the tongues  92  would contact the body  62  of the rack pins  60  and prevent the re-combinating sidebar  100  from moving inward. 
     To complete the reprogramming, it is necessary for the user to insert a new reset key  150 B′ as illustrated in  FIGS. 25 and 26 . By “new”, it is meant that the reset key  150 B′ has a tooth and notch  152  configuration which matches the configuration of the intended or new user key to which the lock cylinder assembly  10  is to be programmed. When the new reset key  150 B′ is inserted, each of the tongue pins  90  is moved to a desired position relative to a respective rack pin  60 . Additionally, the protruding tip  154 ′ of the new reset key  150 B′ engages the actuator reset contact  124  and disengages the reset actuator  120 . 
     The new reset key  150 B′ is rotated in the reverse direction, as indicated by arrow D in  FIG. 27 , which causes the tapered bar  104  to ride up the tapered groove  27  and move the re-combinating sidebar  100  radially inward. As the re-combinating sidebar  100  moves radially inward, the tongue pins  90  move in the direction indicated by arrow E, thereby engaging each tongue  92  with a corresponding engagement passage  66  based on new reset key  150 B′ tooth and notch  152  configuration. 
     Once the cylinder plug  40  is returned to the home position as illustrated in  FIG. 28 , the key  150 B′ is removed. Upon removal, the reset actuator  120  is biased toward the re-combinating sidebar  100  such that post  103  is received in bore  126 , thereby locking the re-combinating sidebar  100  and the associated tongue pins  90  in position. The reprogrammed lock cylinder assembly  10  may thereafter be operated in a normal manner with user keys  150  having the new configuration. 
     A programmable lock cylinder assembly  210  in accordance with a second embodiment of the invention is illustrated and described with reference to  FIGS. 29-55 . Referring to  FIGS. 29-38 , the programmable lock assembly  210  generally comprises a lock housing  220  and a cylinder plug  240 . The lock housing  220  includes a body  222  defining a generally tubular opening  224  extending the length thereof. The tubular opening  224  is configured to receive the cylindrical body  242  of the cylinder plug. Referring to  FIG. 30 , the cylinder plug  240  preferably extends out the opposite end of the housing  220  and is configured for connection to an output mechanism (not shown) for transmitting force from the cylinder plug  240  to one or more elements connected to the lock cylinder assembly  210 . The output mechanism can take a number of different forms, including without limitation, a lever, drive shaft, coupling, cam, or other element mounted to the lock cylinder assembly  210 . The present lock cylinder assembly may be utilized in any desired application. In the illustrated embodiment, a snap ring  230  engages a groove  246  in the cylinder body  242  to retain the lock cylinder assembly  210  in the assembled state illustrated in  FIG. 30 . 
     Referring to  FIGS. 29 and 37 , the housing body  222  includes a pair of tapered grooves  225  and  227  extending along the inside surface of the opening  224 . As in the previous embodiment, a sidebar  280  extends from the cylinder plug  240  and engages the tapered groove  225  to maintain the cylinder plug  240  rotationally locked relative to the housing  220  unless a proper key is positioned in the keyway  239  of the cylinder plug  240 . The tapered groove  227  facilitates reprogramming of the lock cylinder assembly  210 , as described in more detail hereinafter. 
     Referring to  FIGS. 29 and 38 , the housing body  222  may include a plurality of through bores  229  which align with rack pin bores  241  of the cylinder plug  240  when the cylinder plug  240  is positioned in a home position. The through bores  229  are configured to receive a portion of an associated rack pin  60 , as described hereinafter, to further maintain the cylinder plug  240  rotationally locked relative to the housing  220  unless a proper key is positioned in the keyway  239  of the cylinder plug  240 . Desirably, through bores  229  are provided on the upper and lower surfaces, in the illustrated orientation, such that the lock cylinder assembly  210  may be provided with upper and lower rack pins, if desired, for operation with a key having teeth on its upper and lower surfaces. 
     Referring to  FIGS. 29 ,  32 ,  34  and  38 , the rack pin bores  241  extend substantially parallel to the keyway  239  of the cylinder plug  240 . Each rack pin bore  241  is configured to receive and guide the axial movement of a rack pin  60 . The rack pins  60  are substantially the same as the rack pins  60  of the previous embodiment as shown in  FIG. 9 . Each rack pin bore  241  desirably extends completely through the cylinder plug  240  such that the associated rack pin  60  may be configured to be moved upward or downward into engagement with an associated through bore  229 , however, such is not required. Alternatively, the rack pin bores  241  may only extend from one is surface of the cylinder plug body  242 , or may even be completely internal within the cylinder plug body  242  such that the rack pins do not extend from the cylinder plug  240 . 
     Referring to  FIGS. 29 ,  32 ,  34  and  35 , a sidebar opening  248  extends through a side surface of the cylinder body  242  in communication with the rack pin bores  241 . The sidebar opening  248  is sized to receive a sidebar  280  such that a tapered portion  284  of the sidebar  280  is radially extendable from the cylinder plug  240 . In the home position illustrated in  FIG. 37 , the tapered portion  284  extends from the cylinder plug  240  and is engaged in the tapered groove  225  to rotationally lock the cylinder plug  240  relative to the housing  220 . One or more springs  286  are positioned between a rail portion  282  of the sidebar  280  and internal portions  249  of the cylinder body  242  to bias the sidebar radially outward. 
     The sidebar  280  is prevented from being moved radially inward, and thereby unlocking the lock, by the rack pins  60  unless a proper key is positioned in the keyway  239 . The rack pins  60  of the present embodiment have the same configuration as the exemplary rack pin  60  illustrated in  FIG. 9 , but may have other configurations. As explained above, each rack pin  60  also includes a sidebar notch  64  configured to receive the rail portion  282  of the sidebar  280 . As illustrated in  FIG. 37 , the rack pin body  62  generally has a thickness such that the rack pin body  62  contacts the sidebar rail portion  282  and prevents radial movement of the sidebar  280 . When a proper key  350  is inserted in the keyway  239 , the rack pin  60  is moved axially, as described below, such that the sidebar notch  64  is aligned with the sidebar rail portion  282  as shown in  FIG. 39 . With each rack pin  60  so aligned, the sidebar  280  is movable radially inward. In the present embodiment, the sidebar  280  does not automatically move radially inward, but instead is biased radially outward as explained above. Referring to  FIG. 41 , with the proper key  350  inserted, the rack pins  60  are disengaged from the through bores  229  and the sidebar notches  64  are properly aligned, such that rotation of the key  350  causes the tapered portion  284  of the sidebar  280  to ride up the tapered groove  225  as the sidebar rail portion  282  is received in the notches  64 . The lock cylinder assembly  210  is in an unlocked condition such that the cylinder plug  240  is rotatable relative to the housing  220 . Rotation of the cylinder plug  240  actuates the output mechanism. When the key  350  is rotated back to the home position, the sidebar  280  automatically extends radially into engagement with the tapered groove  225 . When the key  350  is removed, the rack pins  60  return to the home position wherein the notch  64  is no longer aligned with the sidebar rail portion  282  and the sidebar  280  is prevented from moving radially inward. 
     To facilitate axial movement of the rack pins  60  in response to an inserted key, each rack pin  60  is associated with a tongue pin  290  which extends perpendicular to the rack pin  60  across the keyway  239 . Each tongue pin  290  includes a tongue  292  that is selectively engagable with one of the engagement passages  66  of the rack pin  60  through an opening  65  in the back of the rack pin  60  (see  FIG. 36 ). In the present embodiment, the engagement passages  66  have a serrated configuration and the tongues  292  have a corresponding inverted triangular configuration, however, other complementary configurations may also be utilized. 
     In the present embodiment, each tongue pin  290  has a circular body portion  294  opposite the tongue  292 . The circular body portion  294  is configured to be received in a corresponding circular bore  310  of the re-combinating sidebar  300  as described hereinafter. The corresponding circular configurations guide the tongue pins  290  as they move up and down in the bores  310 . Other corresponding shapes other than circular may also be utilized. 
     Referring to  FIGS. 36 and 37 , a detent  295  is provided in each circular body portion  294  and is configured to receive a spring  278  or the like extends between a top cover  270  and the respective tongue pin  290  to bias the tongue pin  290  downward. When the tongue pin  290  is engaged with a corresponding rack pin  60 , the spring  278  thereby biases the rack pin  60  toward the locked position wherein the rack pin end  68  extends into the housing though bore  229  and the notch  64  is not aligned with the sidebar rail portion  282 . As shown in  FIG. 32 , the cylinder body  242  desirably includes an open area  243  configured to receive the body of the re-combinating sidebar  300  which includes the bores  310 . 
     In the present embodiment, the re-combinating sidebar  300  is utilized to control the selective engagement between the tongue  292  and the engagement passage  66 , as described in more detail below. Referring to  FIGS. 29 ,  32 ,  33  and  37 , the re-combinating sidebar  300  includes a body portion  302  which defines the bores  310 . A key contact surface  311  is provided between each adjacent pair of the bores  310 , the key contact surfaces  311  spaced from the body portion  302  such that a sidebar keyway  312  is defined between the contact surfaces  311  and the body portion  302 , as shown in  FIG. 29 . The tongue pins  290  extend across the sidebar keyway  312  such that they are engaged when a key  350  is inserted therein. A tapered bar  304  extends perpendicular from the body portion  302  opposite the bores  310 . Guide members  306  extend from each end of the body portion  302  and are configured to be received in guide slots  251  in the cylinder body  242  (see  FIG. 36 ). Positioning of the guide members  306  in the respective guide slots  251  guides radial movement of the re-combinating sidebar  300 . The tapered bar  304  extends radially outwardly from the open area  243  of the cylinder plug  240 . A spring  308  or the like is positioned within each guide slot between the cylinder body  242  and the tapered bar  304  such that the re-combinating sidebar  300  is biased radially outward. 
     Referring to  FIG. 37 , during normal operation, the re-combinating sidebar  300  is maintained in a radially inward position by engagement of the tapered bar  304  with the inside surface  224  of the housing  220 . In the radially inward position, each tongue  292  of the tongue pins  290  remains engaged with the intended engagement passage  66  of the corresponding rack pin  60 . With reference to  FIGS. 41 and 42 , even if a user key  350  is inserted into the keyway  239  and the cylinder plug  230  is rotated, for example, to a position where the tapered bar  304  is circumferentially aligned with the tapered groove  227 , contact of the key contact surfaces  311  of the sidebar  300  against the shank of the user key  350  prevents the sidebar  300  from moving radially outward, thereby maintaining the sidebar  300  in the normal operation mode. As will be described in more detail hereinafter, the reset key  350 ′ has a thinned shank portion, such that a clearance is defined between the key shank  351 ′ and the key contact surfaces  311  and the sidebar  300  is free to be urged radially outward, thereby disengaging the tongue pins  290  from the rack pins  60 . 
     Referring to  FIGS. 29 ,  36 ,  50  and  51 , a reset actuator  320  is positioned between the cylinder plug  240  and the sidebar  300  and is configured to maintain the sidebar  300  in a radially outward position during resetting. The reset actuator  320  includes an actuator body  322  with a reset contact  324  extending therefrom. An upper surface of the actuator body  322  includes a block  326  configured to engage a portion of the sidebar  300 . A post  328  extends from the actuator body  322  and is configured to receive a spring  330  or the like such that the reset actuator  320  is spring biased within a groove in the plug cylinder  240 , as shown in  FIG. 36 . As shown in  FIGS. 50 and 53 , the sidebar body portion  302  includes a notch  303  which defines a radially inner shoulder  305  and a radially outer shoulder  307 . The block  326  engages the inner shoulder  305  when the sidebar  300  is locked in the resetting position as will be described. The spring  330  or the like biases the actuator  320  to this position once the cylinder plug  240  has been rotated to the reset position by an appropriate reset key and the sidebar  300  has been moved radially outward. The reset actuator  320  is biased toward engagement with the inner shoulder  305  until a proper reset key  350 ′ is positioned in the keyway  239 . 
     Referring to  FIGS. 45-47 , the present embodiment of the invention utilizes two distinct types of keys, namely a user key  350  and a reset key  350 ′. Both keys  350 ,  350 ′ include a plurality of teeth and notches  352 , but the reset key  350 ′ includes a protrusion  354  adjacent where the key shank  351 ′ meets the key head  353 . Additionally, as explained above, the shank  351  of the user key  350  is thicker compared to the shank  351 ′ of the reset key  350 ′ such that the user key  350  does not allow the sidebar  300  to move radially outward. Additionally, due to the thicker shank  351  of the user key  350 , the key contact surface  311  will block entry of a user key  350  when the cylinder plug  240  is in the reset position as shown in  FIG. 51 . 
     Having generally described the components of the lock cylinder assembly  210 , normal operation and reprogramming thereof will now be described with reference to  FIGS. 37-55 . The lock cylinder assembly  210  is shown in  FIGS. 37  and  38  in an originally assembled configuration with each tongue pin  290  engaged with a respective rack pin  60  such that a key biting is defined for each rack pin  60 . In the locked position shown, the springs  278  bias the tongue pins  290 , and thereby the rack pins  60  to a lower position wherein the sidebar rail portion  282  is misaligned with the rack pin notches  64 . As such, the sidebar tapered portion  284  engages the tapered groove  225  and the rack pin body portions  62  engage the housing bores  229 , thereby preventing rotation of the cylinder plug  240  relative to the housing  220 . 
     To operate the lock cylinder assembly  210  in normal operation, an appropriate user key  350  is inserted into the keyway  239  as shown in  FIGS. 39 and 40 . As the user key  350  is inserted, the teeth and notches  352  engage the respective tongue pins  290 , thereby raising the rack pins  60  to an unlocked position wherein the notches  64  are all aligned with the sidebar rail portion  282  and the rack pin body portions  62  are disengaged from the housing bores  229 . 
     The user then turns the user key  350  as illustrated in  FIGS. 41 and 42 . Since the sidebar rail portion  282  is aligned with the notches  64 , the sidebar tapered portion  284  rides up the tapered groove  225  as the sidebar rail portion  282  is received in the notches  64 . The plug cylinder  240  is freely rotated relative to the housing  220 . As explained above, even if the plug cylinder  240  is rotated such that the tapered bar  304  is circumferentially aligned with the tapered groove  227 , contact of the key contact surfaces  311  of the sidebar  300  against the shank  351  of the user key  350  prevents the sidebar  300  from moving radially outward, as shown in  FIG. 43 . As such, the tongue pins  290  are maintained in engagement with the rack pins  60 . 
     If a user desires to reprogram the lock cylinder assembly  210  without disassembling the lock cylinder assembly, the user may insert a proper reset key  350 ′ as shown in  FIG. 44 . As explained below, reprogramming of the lock cylinder assembly  210  requires rotation of the cylinder plug  240 . As such, inserting an improper key, i.e. one not having the proper biting, will not allow reprogramming because the improper key will not properly move the rack pins  60  and the cylinder plug  240  will not be rotatable. 
     To reprogram the lock cylinder assembly  210 , the user inserts a current reset key  350 A′ into the keyway. By “current”, it is meant that the reset key  350 A′ has a tooth and notch  352  configuration which matches the currently programmed configuration of the lock cylinder assembly  210 . When the current reset key  350 A′ is inserted, the key  350 A′ engages each of the tongue pins  290  and moves the respective rack pins  60  to the unlock position shown in  FIG. 44  wherein each notch  64  is aligned with the sidebar rail portion  282 . The current reset key  350 A′ is then rotated in the direction of arrow A in  FIG. 48 . While counterclockwise rotation is illustrated in the present embodiment, the invention is not limited to such, as illustrated above. As with normal operation, the sidebar tapered portion  284  rides up the tapered groove  225  as the sidebar rail portion  282  is received in the notches  64 . Rotation of the key and cylinder plug  240  is continued until the tapered bar  304  is aligned with the tapered groove  227  in the housing  220 . The springs  308  bias the re-combinating sidebar  300  radially outward as the tapered bar  304  enters the tapered groove  227 . As the re-combinating sidebar  300  moves radially outward, each tongue pin  290  is also moved in the direction of arrow B in  FIG. 48  such that the tongues  292  disengage from the respective engagement passages  66 . The rack pins  60  stay aligned with the sidebar  280  based on the engagement of the rail portion  282  in each of the notches  64 . 
     Referring to  FIGS. 49 and 50 , the current reset key  350 A′ is removed whereby the top springs  278  bias the tongue pins  290  to a lower most position wherein the tongues  292  are not aligned with any of the engagement passages  66 . Additionally, as shown in  FIG. 50 , when the current reset key  350 A′ is removed, the reset actuator  320  is no longer engaged by the protrusion  354  of the reset key  350 ′ and the spring  330  biases the reset actuator  320  such that the actuator block  326  engages the inner shoulder  305 , thereby maintaining the re-combinating sidebar  300  in the radially outward, reprogram position. As explained above, a user is prevented from inserting a regular user key (non-reset key) and trying to return the cylinder plug  240  to the home position by the sidebar key contacting surfaces  311  extending within the keyway  239  as shown in  FIG. 52 . Additionally, because the tongues  292  do not align with any engagement passages, a user would not be able to insert an object into the keyway to try to bypass the reset actuator  320  as the tongues  292  would contact the body  62  of the rack pins  60  and prevent the re-combinating sidebar  300  from moving inward. 
     To complete the reprogramming, it is necessary for the user to insert a new reset key  350 B′ as illustrated in  FIGS. 52 and 53 . By “new”, it is meant that the reset key  350 B′ has a tooth and notch  352  configuration which matches the configuration of the intended or new user key to which the lock cylinder assembly  210  is to be programmed. When the new reset key  350 B′ is inserted, each of the tongue pins  290  is moved to a desired position relative to a respective rack pin  60 . Additionally, the protrusion  354  of the new reset key  350 B′ engages the actuator reset contact  324  and disengages the reset actuator block  326  from the inner shoulder  305 , instead aligning the block  326  with the outer shoulder  307 . Accordingly, the re-combinating sidebar  300  is free to move radially inward. 
     The new reset key  350 B′ is rotated in the reverse direction, as indicated by arrow C in  FIG. 54 , which causes the tapered bar  304  to ride up the tapered groove  227  and move the re-combinating sidebar  300  radially inward. As the re-combinating sidebar  300  moves radially inward, the tongue pins  290  move in the direction indicated by arrow D, thereby engaging each tongue  292  with a corresponding engagement passage  66  based on new reset key  350 B′ tooth and notch  352  configuration. 
     Once the cylinder plug  240  is returned to the home position as illustrated in  FIG. 55 , the key  350 B′ is removed. Upon removal, the reset actuator  320  remains received within notch  303  against the outer shoulder  307  with the re-combinating sidebar  300  maintained in the radially inward position by contact of the tapered bar  304  against the housing inside surface  224 . The reprogrammed lock cylinder assembly  210  may thereafter be operated in a normal manner with user keys  350  having the new configuration. 
     Referring to  FIGS. 56-63 , an alternative embodiment of the invention will be described. The lock cylinder assembly is substantially the same as in one of the previous embodiments, but further includes master key capability. The master key capability is achieved utilizing a master locking sidebar  80 ′ and master rack pins  60 A′ and  60 B′, as described in more detail hereinafter. In all other respects, the lock cylinder assemblies of the present invention work in the same manner as described above. 
     Referring to  FIG. 56 , the master locking sidebar  80 ′ includes a tapered portion  84  and a rail portion  82 ′. In the present embodiment, the rail portion  82 ′ is segmented rather than a continuous rail. The rail portion  82 ′ has a height A and is configured to be received in notches  64 ′ in the rack pins  60 A′ and  60 B′. Master bar tongues  88  are provided along the sidebar  80 ′ and are configured to align with the engagement passages  66 ′ in the master rack pins  60 A′ and  60 B′. 
     Referring to  FIG. 57 , master rack pin  60 A′ includes a body  62  with a sidebar notch  64 A′ configured to receive the sidebar rail portion  82 ′. The master rack pin  60 A′ also includes a series of engagement passages  66 ′ configured to receive the tongue pin tongues  92  as in the previous embodiment and to also receive the master bar tongues  88 . The height of the notch  64 A′ is equal to the rail portion height A plus the height X of one of the engagement passages  66 ′. As such, as illustrated in  FIGS. 59 and 60 , the rail portion  82 ′ will be received in the notch  64 ′ based on two different key configurations, one being one bitting away from the other. 
     Referring to  FIG. 58 , master rack pin  60 B′ includes a body  62  with a sidebar notch  64 B′ configured to receive the sidebar rail portion  82 ′. The master rack pin  60 B′ also includes a series of engagement passages  66 ′ configured to receive the tongue pin tongues  92  as in the previous embodiment and to also receive the master bar tongues  88 . The height of the notch  64 A′ is equal to the rail portion height A plus the height  2 X of two of the engagement passages  66 ′. However, to prevent the toothing of rack pin  60 A′ from also working in rack pin  60 B′, the passage  66 ′ two above the notch  64 B′, is blocked by a blocker  67  therein. As such, as illustrated in  FIGS. 61 and 62 , the rail portion  82 ′ will be received in the notch  64 ′ based on two different key configurations, one being two bittings away from the other, however, it will not be receivable base on only one bitting difference as the master bar tongue  88  will contact the blocker  67 . Other variations in the size and bitting arrangement may also be utilized. 
     By including various combinations of the master rack pins  60 A′ and  60 B′ in the lock cylinder assembly, such can be master keyed in various manners. An illustrative master keying system is described in U.S. Pat. No. 6,516,644 which is incorporated herein in its entirety. 
     While preferred embodiments of the invention have been shown and described herein, it will be understood that such embodiments are provided by way of example only. Numerous variations, changes and substitutions will occur to those skilled in the art without departing from the spirit of the invention. Accordingly, it is intended that the appended claims cover all such variations as fall within the spirit and scope of the invention.