Patent Publication Number: US-8109122-B2

Title: Programmable lock having incidental change control

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation application of U.S. application Ser. No. 12/116,592, filed on May 7, 2008, now U.S. Pat. No. 7,802,455 which claims the benefit of U.S. Provisional Application No. 60/916,367, filed May 7, 2007, the disclosures of which are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates generally to cylinder locks, and more particularly to a programmable cylinder lock that controls changing of the lock configuration, including incidental of accidental configuration changes. 
     Pin and tumbler locks are known that can operate with one of a set of user keys, and can be reconfigured without disassembling the lock, as disclosed in US Patent Publication 2004 -0221630, the disclosure of which is incorporated herein by reference. The lock shows a changeable lock assembly with a plug that rotates within a housing, with a series of pins and tumbler, that when aligned at the interface between the plug and the housing, permit rotation of the plug to lock and unlock a latch or catch. One or more change balls are included in the one or more pin chambers, which can move between the pin chamber and the blind hole formed in the side of the plug, to configure the lock with different keys of a set of user keys, depending upon the configuration of the one or more change balls in either the pin chamber or the blind hole. 
     With this lock, a phenomenon known as incidental keying can occur. In one circumstance of incidental keying, a user key that operates the lock may be used wherein, while being rotated, the key is being pulled axially in the key removal direction, which can cause a raised contour position in an adjacent pin chamber to incidentally or accidentally raise a change ball up into a change member and then into a corresponding retainer cavity when the plug is rotated to the user position. In another circumstance, an unauthorized user key can have a particular pin position with a contour cut that is slightly higher than that of the authorized user key, so that the unauthorized user key with the slightly higher contour height can incidentally or accidentally cause the change ball to be lifted out of the pin chamber and trapped in the driver chamber as the plug begins to rotate to the second rotated or programming position. When the plug arrives at the change position, the change ball is driven down into the retainer cavity, causing incidental or accidental re-keying, because now the lock will not operate with the original authorized user key. 
     Thus, it would be desirable to provide a lock, and particularly a lock that permits rapid programming of the tumbler pins or other pins to a different configuration to operate with a different user key, without disassembling the lock or re-pinning (exchanging) the tumbler pins, which reduces or eliminates incidental or accidental re-keying of the lock. 
     SUMMARY OF THE INVENTION 
     The present invention provides a cylinder lock for operating a bolt, a latch or other closure mechanism, which can be programmed for use with one of a plurality of user keys without disassembling the lock or exchanging or re-pinning the tumbler pins, with elimination or reduction of incidental or accidental re-keying of the lock. 
     The present invention relates to a programmable cylinder lock assembly that can be reconfigured to operate with a user key selected from a set of keys, without disassembling the lock. The lock assembly includes: a set of keys comprising a plurality of user keys; a housing having a cylindrical bore with an inner surface and a plurality of driver chambers intersecting the bore surface; a plurality of drivers, each driver being movable within one driver chamber and having a means for urging the drivers toward the inner surface; and a plug having a cylindrical periphery and rotatably mounted within the bore so as to form a shear surface at the interface of the inner surface, the plug being rotatable from a key insertion position to an operating position, and to a programming position. The plug has a keyway configured to receive a key selected from the set of keys, a plurality of tumbler chambers intersecting the plug periphery and the keyway, each tumbler chamber being aligned with a corresponding one of the plurality of driver chambers when the plug is at the key insertion position so as to form a corresponding pin chamber, and at least one retainer cavity disposed within the plug, spaced apart from a corresponding one of the plurality of tumbler chambers, and being alignable with the corresponding driver chamber when the plug is at the programming position. The lock assembly further includes a plurality of tumblers, each tumbler being movable within a corresponding one of the plurality of tumbler chambers, and at least one lock configuration change member, movable within the lock between at least a first position within the corresponding pin chamber or the corresponding driver chamber, and a second position within the corresponding at least one retainer cavity. 
     The lock further includes a means for isolating the at least one retainer cavity from the corresponding driver chamber when the plug is in the programming position, having a first position of condition that prevents movement of the change member from the corresponding driver chamber into the at least one retainer cavity, and movement of the change member out of the at least one retainer cavity and into the corresponding driver chamber, and a second position that permits or allows such movements. 
     One embodiment of the isolating means comprises a cavity carriage movably positioned within the plug, within which the at least one retainer cavity is formed, the cavity carriage movable relative to the plug between a first aligned position wherein the at least one retainer cavity is aligned with the corresponding driver chamber, where the change member can be moved between the at least one retainer cavity and the corresponding driver chamber when the plug is in the programming position, and a second non-aligned position wherein the at least one retainer cavity is not aligned with the corresponding driver chamber, and the change member can not be moved between the at least one retainer cavity and the corresponding driver chamber when the plug is in the programming position. 
     In one such embodiment, a surface of the cavity carriage forms a portion of the periphery of the plug, wherein the at least one retainer cavity and the opening into the cavity are both formed into the surface of the cavity carriage. 
     In another embodiment, the cavity carriage is disposed within a channel formed within the plug and below or inboard the outer periphery of the plug, wherein the at least one retainer cavity is formed into the cavity carriage, and an opening into the at least one retainer cavity is formed within the outer periphery of the plug. In another such embodiment, the cavity carriage moves by rotation within a first channel of the plug around an axis of the cavity carriage. In another such embodiment, the cavity carriage moves axially within a second channel along an axis of the cavity carriage. 
     Another embodiment of the isolating means comprises an obstruction associated or integral with the plug, being moveable relative to the plug between a first position that does not block the opening into the at least one retainer cavity formed into the plug, when the plug is in the programming position, and a second position that blocks or obstructs the opening, to prevent movement of the change member from the corresponding driver chamber into the retainer cavity. 
     In one embodiment, the obstruction is a member that blocks a portion of the opening of the at least one retainer cavity when disposed in the second position. In another embodiment, the obstruction forms a part of the plug periphery, and moves tangentially between the first position and the second position. In yet another such embodiment, the obstruction moves axially between the first position and the second position. 
     Another embodiment of the present invention can include a means for displacing the at least one change member from the second position within the at least one retainer cavity to the corresponding driver chamber when the lock is in the programming position. 
     The configuration of the lock for operation with a user key is associated with the positioning of the at least one change members in either the corresponding pin chamber or the corresponding retainer cavity. 
     The cavity carriage of the lock can optionally have a change slot that intersects a portion of the at least one retainer cavity and can include a change tool that can be manipulated within or engaged in the change slot, whereby the change member can be moved from the second position within the at least one retainer cavity. 
     The invention also relates to a programmable lock assembly that can further be configured for operation with a temporary access key, associated with a main user key of the set of keys, for temporarily operating the lock. The main user key can be configured alternatively to cancel operation with the associated temporary user key, or to continue allowing operation with the associated temporary user key, when the main user key is again inserted into and operates the lock. Suchlock assembly uses a means for positioning a temporary lock configuration change member within the lock for establishing the temporary lock configuration. 
     The present invention also relates to a lock kit, comprising: a) a programmable lock assembly including a set of keys, as described herein; b) instructions for use; c) optionally a change tool; and d) a means for securing together the lock assembly, the optional change tool, and the instructions. 
     The present invention relates to a method for moving a change member from the corresponding pin chamber to the corresponding retainer cavity of the lock assembly, comprising the steps of: a) inserting a key having at least one contour position configured to raise a change member disposed in the pin chamber, up into the corresponding driver chamber; b) rotating the plug to the programming position while the at least one change member is in the driver chamber; and c) moving the cavity carriage from its second position to its first position, whereby the change member is moved from the driver chamber into the retainer cavity. 
     The present invention relates to a method for moving a change member from the corresponding pin chamber to the corresponding retainer cavity of the lock assembly, comprising the steps of: a) inserting a key having at least one contour position configured to raise a change member disposed in the pin chamber, up into the corresponding driver chamber; b) rotating the plug to the programming position while the at least one change member is in the driver chamber; and c) moving an obstruction from its second position to its first position, whereby the change member is moved from the driver chamber into the retainer cavity. 
     The present invention also relates to a method for moving a change member from the corresponding retainer cavity to the corresponding driver chamber, comprising the steps of: a) inserting a key operable to rotate the plug to the programming position; b) rotating the plug to the programming position; c) moving the cavity carriage from its second position to its first position; d) displacing the at least one change member from the retainer cavity into the corresponding driver chamber; e) rotating the plug to the key insertion position while the at least one change ball is in the driver chamber, thereby disposing the change ball in the pin chamber; f) optionally moving the cavity carriage from the first position to its second position; and g) removing the inserted key. 
     The present invention also relates to a method for moving a change member from the corresponding retainer cavity to the corresponding driver chamber, comprising the steps of: a) inserting a key operable to rotate the plug to the programming position; b) rotating the plug to the programming position; c) moving the obstruction from its second position to its first position; d) displacing the at least one change member from the retainer cavity into the corresponding driver chamber; e) rotating the plug to the key insertion position while the at least one change ball is in the driver chamber, thereby disposing the change ball in the pin chamber; f) optionally moving the cavity carriage from the first position to its second position; and g) removing the inserted key. 
     The present invention also relates to a method for programming a lock operable with a first user key, to be operated by a second user key, without disassembling the lock, the method comprising the steps of: a) providing a set of keys comprising at least a first user key and a second user key, and a programming key, each of the keys having a contour edge, the second user key having a different contour edge than the first user key at at least one of the corresponding pin chamber positions; b) inserting the programming key into the keyway and rotating the plug to the programming position; c) moving the cavity carriage from its second position to its first position; d) displacing the at least one change member from the corresponding retainer cavity into the corresponding driver chamber; e) rotating the plug to the key insertion position while the at least one change member is in the corresponding driver chamber; f) optionally moving the cavity carriage from its first position back to its second position; and g) removing the programming key, thereby configuring the lock into a reset configuration. The method can further comprise the steps of: h) inserting the second user key while the lock is in the reset configuration, wherein at least one change member is displaced from the corresponding tumbler chamber into a corresponding driver chamber; i) rotating the plug to the programming position while the at least one change member is in the corresponding driver chamber; j) moving the cavity carriage from its second position to its first position, whereby the change member moves from the driver chamber to the corresponding retainer cavity, and k) rotating the plug back to the first position wherein the lock is configured for operation by the second user key. 
     In another aspect of the invention, the plug of the lock is configured to permit rotation in a first direction to an operating position when using a user key, and in an opposite direction to a programming position when using a programming key, which permits reconfigurating or programming of the lock for use with a different user key. The lock cannot be rotated to the programming position with the user keys. 
     In another aspect of the invention, the configuration of the lock can be changed to operate with a second user key, and subsequently with a third user key, of the set of keys solely in response to insertion of the second user key, and subsequently the third user key, and rotation of the plug to the operating position. The reconfigured lock then cannot be operated by the first user key, and subsequently the second user key, respectively. 
     The present invention therefore relates to a key-operated, programmable lock that can operate the lock with any one of a plurality of user keys, and is programmable with a programming key to reconfigure the lock to operate with another one of the plurality of user keys, without disassembling the lock. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with a general description of the invention given above, and the detailed description of the embodiments given below, serve to explain the principles of the invention. 
         FIG. 1  shows a perspective, exploded view of an embodiment of a programmable lock of the present invention. 
         FIG. 2  shows a perspective, assembled view of the same programmable lock. 
         FIG. 3  shows a set of keys, a change tool and a cavity carriage employed in the programmable lock. 
         FIG. 4  shows a lateral sectional view of the cavity carriage through line  4 - 4  of  FIG. 2 . 
         FIG. 5  shows a longitudinal sectional view of the programmable lock through line  5 - 5  of  FIG. 2 . 
         FIG. 6  shows a lateral sectional view of the programmable lock through line  6 - 6  of  FIG. 2 . 
         FIG. 7  shows the lock with a first user key inserted in the keyway. 
         FIG. 8  shows the first user key partially rotating the plug in the lock. 
         FIG. 9  shows the first user key rotating the lock to a programming position. 
         FIG. 10  shows a sectional view of the lock taken through line  10 - 10  in  FIG. 9 . 
         FIG. 11  shows the lock shown in  FIG. 10  after depressing inward the cavity carriage. 
         FIG. 12  shows the lock returned to the key insertion position, with the first user key removed, and a programming key inserted into the keyway. 
         FIG. 13  shows the programming key rotating the plug to the programming position. 
         FIG. 14  shows a sectional view of the lock taken through line  14 - 14  in  FIG. 13 . 
         FIG. 15  shows the lock of  FIG. 14  after depressing inward the cavity carriage, to deposit change balls into the cavity carriage. 
         FIG. 16  shows the lock of  FIG. 15  after the cavity carriage is released outward. 
         FIG. 17  shows the lock of  FIG. 16  upon initial engaging of a change tool into the slot of the cavity carriage. 
         FIG. 18  shows the lock of  FIG. 17  after the change tool has moved the cavity carriage inward. 
         FIG. 19  shows the lock of  FIG. 18  after the change tool has displaced change balls out of the cavity carriage. 
         FIG. 20  shows the lock of  FIG. 19  after the change tool and cavity carriage are released outward. 
         FIG. 21  shows the lock of  FIG. 20  after the change tool has been removed from the cavity carriage. 
         FIG. 22  shows the lock of  FIG. 21  in perspective view. 
         FIG. 23  shows the lock of  FIG. 22  after the programming key has rotated the lock to the key insertion position. 
         FIG. 24  shows the lock of  FIG. 23  with the programming key withdrawn, and a second user key inserted. 
         FIG. 25  shows the lock of  FIG. 24  where the second user key has rotated the plug to the programming position. 
         FIG. 26  show the lock of  FIG. 25  after depressing inward the cavity carriage, just before certain change balls drop into the cavity carriage. 
         FIG. 27  shows a sectional view of the lock of  FIG. 26 , after the change balls have dropped into the cavity carriage. 
         FIG. 28  shows a perspective view of the lock after the second user key has rotated the plug back to the key insertion position. 
         FIG. 29  shows the lock with a second embodiment of a cavity carriage. 
         FIG. 30  shows a horizontal sectional view of the cavity carriage through line  30 - 30  of  FIG. 29 . 
         FIG. 31  shows the lock of  FIG. 30 , with the cavity carriage rotated to a second position. 
         FIG. 32  shows a vertical sectional view of the lock of  FIG. 31 , with the programming key inserted and the plug rotated to the programming position. 
         FIG. 33  shows the lock of  FIG. 32  with the change tool inserted partly into the slot and the cavity carriage rotated to the first position. 
         FIG. 34  shows the lock of  FIG. 33  after the change tool has displaced change balls out of the cavity carriage. 
         FIG. 35  shows the lock with a third embodiment of a cavity carriage 
         FIG. 36   a  shows a horizontal sectional view of the lock and the third cavity carriage through line  36   a - 36   a.    
         FIG. 36   b  shows an exploded view of a portion of  FIG. 36   a.    
         FIG. 37  shows a section view of the lock through line  37 - 37  of  FIG. 35 , after the programming key has been inserted and the plug rotated to the programming position. 
         FIG. 38  shows the lock of  FIG. 37  after depressing inward the cavity carriage, with the change balls partially dropping into the cavity carriage. 
         FIG. 39  shows the lock of  FIG. 38  after the cavity carriage is released outward, with the change balls deposited into the cavity carriage. 
         FIG. 40  shows a lateral sectional view of another embodiment of the programmable lock wherein the longitudinal bore is formed to intersect a portion of the periphery of the plug. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As used herein, the phrase “disassembly of the lock” means the removal of the plug from the bore of the housing and removal of the tumbler pins from the tumbler chambers of the plug, or the removal of an access panel in the housing and removal of the driver pins and tumbler pins. 
     As used herein, the term “isolating” means the temporary separation of a pin within one chamber or cavity of the lock from another chamber or pin. 
     As used herein, the term “integral” means a part or element of a lock that is formed as a unit with the other parts or elements of the lock assembly, which can not be separated from the other parts or elements of the lock assembly without disassembly of the lock, and in particular disassembly of the plug from the housing. 
     A first embodiment of a programmable lock assembly of the present invention is shown in  FIGS. 1 through 28 . This embodiment shows a programmable lock assembly that can be programmed to operate with one of a plurality of user keys. 
       FIGS. 1 and 2  show the lock assembly that includes a housing  20  having a cylindrical barrel portion  21  and a stack portion  22 . The barrel portion  21  has a cylindrical bore that runs through the length of the barrel portion  21  to form an inner surface  23 . A plurality of driver chambers  24  are formed along the length of the stack portion  22 , and intersect the inner surface  23 . The plurality of driver chambers typically includes 5, 6, 7, 8 or 9 such chambers. In the illustrated embodiment, each of the driver chambers  24  has substantially the same diameter, and are aligned transverse to the centerline  100  that passes through the longitudinal center of the barrel portion  21 . The plurality of driver chambers  24  corresponding to pin chambers  1  through  7  may be denoted herein after as driver chambers  124 ,  224 ,  324 ,  424 ,  524 ,  624  and  724 , respectively. 
     The plug  10  of the lock has a cylindrical periphery  12  that is formed or machined to allow the plug  10  to be mounted rotatably within the inner surface  23  of the housing, such that the centerline of the plug is aligned along the centerline  100  for the housing barrel  21 . A cylindrical shear surface is formed at the interface between the periphery  12  of the plug  10  and the inner surface  23  of the housing  20 . A shear line or arc  80  forms a portion of the shear surface, at the intersection of the driver chambers  24  with the bore  23  (see  FIG. 10 ). 
     The lock  1  generally operates under the well-known principle that, provided none of the lock hardware (such as the lock drivers and tumblers, discussed hereinafter) span across the shear line or shear arc  80 , then the plug  10  is free to rotate within the bore in either direction, and the lock operates to open a latch, a bolt or other means of securing a door or other device being secured closed by the lock. On the other hand generally, if a driver or a tumbler spans across the shear line  80 , then the plug  10  is prevented from rotating within the bore in one or both directions, as shown herein after. 
     The plug  10  has a keyway  11  which has been bored or machined out of the plug  10  to provide a passageway for an associated key  40 , such as one of the keys shown in  FIG. 3 . Typically, the keyway  11  extends longitudinally from the front face  33  of the plug toward the rear. The cross sectional shape of the keyway  11  typically remains constant along the longitudinal axis  100  of the plug  12 , and is configured to receive a corresponding shaft portion  67  of a key  40  that has a complementary cross sectional shape along its longitudinal length, as is well-known and practiced conventionally in the lock industry. 
     The plug  10  comprises a plurality of tumbler chambers  13  that penetrate from the plug periphery  12  through the body of the plug  10  to intersect the keyway  11 . The tumbler chambers  13  lie generally in a plane that extends through the keyway  11 . As shown in the illustrated embodiment, the tumbler chambers  13  are generally of the same diameter, and are equally spaced and aligned along the longitudinal length of the plug  10 . Each tumbler chamber  13  is formed or machined along a centerline  300  that intersects and is perpendicular to the axial centerline  100  of the plug. When the tumbler chambers  13  of the plug  10  are axially aligned with the driver chambers  24  of the stack portion  22 , the plug  10  is in a first rotated position with respect to the housing  20 . The plurality of tumbler chambers  13  corresponding to pin chambers  1  through  7  may be denoted herein after as driver chambers  113 ,  213 ,  313 ,  413 ,  513 ,  613  and  713 , respectively. 
     The latch or rear end of the plug can be provided with a means of securement, such as machined threads  31 , which can extend from the end of the housing  20 , and can receive a correspondingly-threaded cap  30  to secure the plug  10  within the housing  20 . A latch  34  can be retained by the cap  30  for engaging a recess or bolt (not shown) to unlock the object, such as a door, padlock, etc., in which the cylinder lock is installed. A spring-loaded stop pin  37  that is secured to or within a bore in the rear end of the plug, engages a hole in the latch  34  to limit the rotation of the latch  34  relative to the plug. The latch can also be a lazy cam latch, and described in U.S. Pat. No. 7,290,418, the disclosure of which is incorporated herein by reference in its entirety. 
     The lock  1  also comprises a plurality of lock hardware elements, comprising a plurality of tumblers  25 , drivers  27 , driver springs  28 , and at least one, or a plurality as shown, of change members  26 . Typically, each pin chamber, formed from an aligned tumbler chamber  13  and corresponding axially aligned driver chamber  24  when the plug  10  is in its first or key insertion position, includes, in sequence, one tumbler  25 , optionally a change member  26 , one driver  27  and one driver spring  28 . The tumblers  25  are generally pencil-shaped, consisting of a cylindrical body with a tapered or conical end. Each tumbler  25  is moveable axially along and within the tumbler chamber  13 , and positioned with the tapered end extending into the keyway  11  when no key is inserted. The plurality of tumblers  25  corresponding to pin chambers  1  through  7  may be denoted herein after as tumblers  125 ,  225 ,  325 ,  425 ,  525 ,  625  and  725 , respectively. 
     Each driver  27  is positioned within driver chamber  24  of the stack portion  22  of the housing, and is moveable axially along and within the driver chamber  24 . The driver  27  typically has a cylindrical body. A driver spring  28  biases the driver  27  toward the inner surface  23  of the housing  20 . The plurality of drivers  27  corresponding to pin chambers  1  through  7  are noted herein after as drivers  127 ,  227 ,  327 ,  427 ,  527 ,  627  and  727 , respectively. The driver spring  28  is typically made of a tempered stainless steel to prevent material deformation upon multiple cycles of compression and extension. Preferably, the spring material is a non-metallic stainless steel wire of about size 008, and is available as part number C108x008x520 from W.B. Jones Spring Co., Inc., of Wilder, Ky. A planar lid  29  can be secured in position to the top of the stack portion  22  to retain the hardware elements after these have been loaded into the pin chambers. 
     The change member  26  is illustrated as a spherical ball. The spherical shape of the change member  26  allows rolling movement within the driver chambers  24 , tumbler chambers  13 , and other passageways in the lock, and projects the same cross-sectional shape (circular) regardless of its orientation. The spherical shape of the change member  26  eliminates corners or edges that can obstruct its free movement, and minimizes wear. A barrel- or cylindrical-shaped change member can be used in a lock of the present invention, although it may have a tendency to tilt or tumble within a chamber and against edges of the change slot, which can increase the potential of becoming lodged within the chamber and jamming the lock. For the purpose of describing succeeding embodiments of the present invention, the change member will hereinafter be referred to as the change ball  26 . 
     As shown in  FIGS. 1 and 2 , the plug  10  has a plurality of openings  16  machined into the periphery  12  of the plug  10 . The openings  16  are of substantially the same circular cross section, and are shown aligned along and disposed perpendicularly to the longitudinal axis of the plug. The plurality of openings  16  are equally spaced, whereby each opening  16  in the periphery  12  is axially aligned and circumferentially displaced from the tumbler chambers  13 . Typically the diameter or minimum size of the opening  16  is larger than, and typically just slightly larger than, the diameter or maximum size of the change ball  26 . The diameter of the opening  16  is smaller than, and typically slightly smaller than, the diameter of the corresponding driver pin. 
     A cavity carriage  50  is illustrated with a cylindrical shaped body  52  that is configured to be disposed and moveable within a cylindrical bore  19  formed in the plug  10 . As illustrated, the bore  19  is formed in the face  33  of the plug, although in other embodiments, the bore opening can be formed in the rear end of the plug. Although the illustrated cavity carriage  50  and its complementary-shaped bore  19  are shown having a circular cross sectional shape, other shapes such as rectilinear and oval can be used in embodiments where the movement of the cavity carriage within the bore is axial. A captured spring  51  biases the axially moveable cavity carriage  50  forward toward the front of the plug. The bore  19  is formed parallel to the axis of the plug, and intersects the plurality of openings  16   
     The cavity carriage  50  is integral with the plug and lock assembly, and can not be separated or removed from the bore  19  without disassembling the plug  10  from the housing. The cavity carriage  50  also has a plurality of retainer cavities  56  formed into the surface and along its length. The retainer cavities  56  are substantially the same size, and are shown formed perpendicular to the longitudinal axis of the cavity carriage and having a circular cross section. The plurality of retainer cavities  56  are equally spaced, and has a pitch, or distance between adjacent retainer cavities, equivalent to the pitch of the driver chambers  24 . The cavity carriage  50  moves within the bore  19  between a first position wherein the plurality of retainer cavities  56  are aligned axially with the corresponding plurality of driver chambers  24  when the plug  10  is rotated to the programming position, and a second position wherein the plurality of retainer cavities  56  are out of alignment with the plurality of driver chambers  24 , and typically when the spring  51  has biased the cavity carriage  50  within the bore  19  toward the front  33  of the plug. The cavity carriage  50  can move axially between the first and second positions substantially independent of the position of the plug  10  within the housing  20 . 
     The cavity carriage  50  has an elongated flat or groove  57  formed in a proximal end of the cavity carriage  50 , in a direction perpendicular to the longitudinal axis, and through the outer periphery of the carriage body as shown. The flat  57  is configured to receive a securing pin  58  that also passes through and is partially retained in a securing hole  59  formed in the periphery of the plug  10 . The relationship between the securing pin  58  and the flat  57  is sliding, such that the portion of the securing pin  58  extending into the flat  57  restrains the cavity carriage  50  from rotation within the bore  19 , and from longitudinal movement beyond a first stop position of the securing pin  58  against the first wall  55   a  of the flat  57 , and beyond a second stop position of the securing pin  58  against the second wall  55   b  of the flat  57 , as shown  FIG. 6 .  FIG. 5  also illustrates the cavity carriage  50  having retainer cavities  56  that are not in axial alignment with the openings  16  or the driver chambers  24  when in its illustrated second position extending toward the front of the lock. One can see that pressing the cavity carriage rearward, which compresses spring  51 , can bring the retainer cavities  56  into axial alignment with the openings  16  in the periphery  12  and the driver chambers  24 . 
     The depth of the bore or cavity of the retainer cavity  56  formed into the cavity carriage  50  is at least as deep as, and typically slightly deeper than, the diameter or maximum size of the change ball  26 . In a typical embodiment, the retainer cavities  56  comprise a means for preventing entry of the drivers  27  therein when the plug is in the programming position and the cavity carriage  50  is depressed into its first or communication position, which permits communication of the change ball between the driver chamber and the retainer cavity. The means for preventing entry of the drivers can comprise the retainer cavities  56  having an opening in the periphery of the cavity carriage  50  that is sized smaller than the drivers  27 , to prevent a driver from dropping into an open retainer cavity  56  when in its communication position. More typically, and often concurrently, the opening  16  in the periphery of the plug  10  is likewise sized smaller than the drivers  27 , to prevent a driver from dropping into an opening  16  when the plug is rotated to the programming position. 
     Also shown in  FIGS. 1 ,  3 ,  4  and  6 , the cavity carriage  50  has a change slot or groove  54  that is formed into the periphery of the cavity carriage  50 , substantially parallel to the axial centerline. The change slot  54  extends from the front head or button end  53 , toward and through one or more of the plurality of retainer cavities  56 . The change slot  54  also extends through a portion of the plurality of retainer cavities  56 . In the illustrated embodiment, the change slot  54  is formed through the centers of the aligned retainer cavities  56 . Typically, the change slot  54  has a radial depth that is at least the same as or slightly more than the depth of the retainer cavities  56 . 
     The change slot  54  is configured to accommodate a blade  61  of a separate change tool  60  that is shown in  FIGS. 1 and 3 . The height of the blade  61  is configured so that the top  65  of the blade aligns proximate with, or slightly below, the periphery  12  of the plug when the blade  61  is inserted into the slot  54 , as shown in  FIG. 19 . The configuration of the change slot  54  allows the inserted change tool  60  to be manipulated therein, to raise any and all change balls  26  contained within the retainer cavity  56  at its center of weight and to its maximum height relative to the retainer cavity  56 . The blade  61  can have a linear upper edge extending along a portion that registers with some or all of the at least one retainer cavities when disposed in its second position fully inserted within the change slot  54 . Alternatively, the blade can have a non-linear or curved upper edge, provided that each position along the edge that registers with all of the retainer cavities can raise the change ball, or member, to a position that allows it to be moved into the corresponding driver chamber. The change slot  54  is typically configured with a minimum width that accommodates the width of the blade  61 , while maintaining effective lifting of the change balls  26 . The width of the change slot  54  is typically about 0.020 inches (about 0.50 mm) or less. Typically the slot has a rectangular cross sectional shape. 
     The lock  1  is associated with a set of keys  40 , a subset portion of which is illustrated in  FIG. 3 . The subset of keys  40  can include a first user key  140 , a second user key  240 , and a programming key  540 . Each of the keys has a shaft portion  47  having a contour edge that comprises a plurality of contour landings  48  that define a plurality of contour positions. In the illustrated embodiment, the contour edge has one contour position corresponding to each of the pin chambers of the lock  1 . Each contour landing  48  is generally flat and parallel with the axis of the key shaft  67 . When any of the keys  40  are inserted fully into the keyway  11  of the plug  10 , the contour positions  1  through  6 , identified as contour positions  41 ,  42 ,  43 ,  44 ,  45 , and  46 , respectively, align with the pin chambers  1  through  6 , respectively. The shaft  67  of a key  40  can be formed or machined to a specific depth at each contour position. The length of each contour landing  48  should be sufficiently long to prevent a tumbler  25  from beginning to descend or ascend prematurely off the end of the contour landing  48  when inserting or withdrawing the key  40  from the keyway  11 . At the same time, the sloped transition portions  49  between adjacent contour landings  48  should be sufficiently shallow in slope to allow the plurality of positioned tumblers  25  to easily run up and down the length of the contour of a key  40  as the key is being inserted into or withdrawn from the keyway  11 . 
     In the illustrated embodiment, the six contour positions  41 ,  42 ,  43 ,  44 ,  45 , and  46  may be denoted herein after as  141 ,  142 ,  143 ,  144 ,  145 , and  146 , respectively, for the first user key  140 ; as  241 ,  242 ,  243 ,  244 ,  245 , and  246 , respectively, for the second user key  240 ; and likewise for the programming key  540 . 
     As is well known in the lock industry, the depth of a contour cut is typically made in relation with the height of the tumbler in the corresponding pin chamber. In the illustrated embodiments, the tumblers are shown having equal lengths (heights) in the tumbler chamber, to assist in illustrating the principals of the present invention. Typically, however, the heights of the various tumblers in the lock will vary, and therefore the corresponding contour cuts of the keys are cut to accommodate the tumbler lengths, as well as the height of the change member in the pin chamber. 
     In the present invention, as illustrated in the Figures, the depth of the cut (or said differently, the height) of the contour is also made in relation to the diameter or height of the change ball  26  associated therewith. That is, if a particular key is intended to raise a change ball  26  above the shear line  80  of the lock, then that key&#39;s corresponding contour position should be cut to a shallow depth (a raised contour) accordingly, which can raise at least the centerline of the change ball  26  above the shear line  80 . In the illustrated embodiments, each user key  140  and  240  has a contour edge that can comprise one or more raised contours  61   a  and  61   b , one or more lowered contours  62   a  and  62   b , and typically a combination of raised and lowered contours. In the present invention, the height of a particular contour position for a user key, for example the first user key ( 140 ) or the second user key ( 240 ), will indicate the key&#39;s ability to raise a change ball  26  above the shear line  80  within that particular pin chamber. For example, the second contour position  142  of first user key  140  has a generally shallow cut (a raised contour position  61   b ), and the second contour position  242  of the second user key  240  has a generally deep cut (a lower contour position  62   b ). The shallow cut (raised contour  61   b ) of the second contour position  142  of user key  140  will allow key  140  to raise any change ball  226  in the second pin chamber  213  above the shear line  80  and into second driver chamber  224 . Conversely, the generally deep cut (lower contour  62   b ) of the second contour position  42  on the second user key  240  will be insufficient to raise the change ball  226  out of the second tumbler chamber  213 . Also, the generally deep cut in the fourth contour position  44  (lowered contour  62   b ) of the first user key  140  does not allow that key to raise a change ball  426  out of the fourth tumbler chamber  413 , whereas the generally shallow cut in the fourth contour position  44  (raised contour  61   b ) of second user key  240  is sufficient to raise at least the centerline of the change ball  426 , and typically the entire change ball, above the shear line  80  and into fourth driver chamber  424 . These principles will be further illustrated in a description of the operation of the key herein after. 
     In the description above, it should be understood that a key configuration that allows a user key to raise a change member to above the shear line  80  also raises the top end of the tumbler  25  to proximate the shear line. This ensures that the change member is displaced into the driver chamber  24 , and that no hardware member (specifically, neither the driver nor the tumbler) in the pin chamber spans the shear line at the key insertion position of the plug, particularly when the change member is in its second position in the retainer cavity, so that the plug can rotate within the housing to the operating position. 
     The lock  1  shown in  FIGS. 2 and 5  is in a null configuration, wherein each of the change balls  26  are disposed in their first positions in the corresponding first six pin chambers  1 - 6 , designated as PC 1 , PC 2 , PC 3 , PC 4 , PC 5 , and PC 6 , respectively. A seventh pin chamber, PC 7 , includes only a driver and a tumbler. In each pin chamber, the change ball  56  resides between the tumbler  25  and the driver  27 . While in the null position, a first user key  140  shown in  FIG. 3  from a set of user keys is inserted as shown in  FIG. 7 . The raised contour positions  1 ,  2  and  6  of user key  140  raise the corresponding tumblers  125 ,  225 , and  625  within the tumbler chambers, which in turn raise the corresponding change balls  126 ,  226  and  626  to a position where their centerlines are clearly above the shear line  80  and within corresponding driver chambers  124 ,  224  and  624 . The remaining change balls  326 ,  426  and  526  have also been raised by their corresponding tumblers, but only to a height wherein they remain within their corresponding tumbler chambers  13 . 
     It can be observed that none of the hardware (drivers  27 , tumblers  25  or change members  26 ) span across the shear line  80  of any of the pin chambers. Thus, as the key  140  starts rotating the plug into a first direction (clockwise, looking at the front of the lock) as shown in  FIG. 8 , change balls  126 ,  226  and  626 , become isolated within the corresponding driver chambers  24 , while change balls  326 ,  426 , and  526  remain within their corresponding tumbler chambers and rotate with the plug  10 . When the rotating plug  10  arrives at the programming position shown in  FIGS. 9 and 10 , the driver chambers  24  have aligned with the opening  16  in the periphery of the plug. 
     As shown in  FIG. 10 , disposed below the openings  16  in the plug is the cylindrical body  52  of the cavity carriage  50 . Each change ball  126 ,  226  and  626  is biased by their corresponding drivers  27  and driver springs  28  against the outer surface of the cylindrical body  52  along the opening of the slot  54 , and between the openings to the retainer cavities  56 . As long as the cavity carriage  50  remains in the second position, biased forward by the spring  51 , communication of the change ball  26  between the driver chamber  24  and the retainer cavity  56  is prevented. That is, the change ball can not move from the driver chamber into the retainer cavity. However, as soon as the cavity carriage  50  is forced rearward against the biasing spring  51 , such as by depressing end  53 , the plurality of retainer cavities  56  align axially with the openings  16  in the plug periphery and with the driver chambers  24 , to allow the change balls  126 ,  226  and  626  to move by the force of the driver springs  28  into the corresponding retainer cavities  156 ,  256  and  656 , as shown in  FIG. 11 . 
     When the first key  140  is used to rotate the plug back to the key insertion position, and key is removed, the lock is then said to be configured for the first user key, with change balls  126 ,  226  and  626  disposed in their second positions within the corresponding retainer cavities, and change balls  326 ,  426  and  526  disposed in the corresponding pin chambers. Consequently, change balls disposed in the driver chambers when the plug is in the programming position, can only be moved into the retainer cavities by movement of the cavity carriage  50  into its first, aligned position. 
     The lock illustrated can be reprogrammed to operate with a different user key by changing the arrangement of change balls between the pin chambers and retainer cavities. In the illustrated embodiment, a programming key  540  is used to rearrange the positioning of the change balls  26  between the several pin chambers PC 1 -PC 6  and the several retainer cavities  156  through  656 . It will also be apparent that the same first user key  140  can be used to reprogram the lock, in place of the programming key, whenever the lock is configured for operation with the first user key (meaning, the first user key can not be used to operate the lock, or to reprogram the lock, when the lock is configured for operation with the second user key  240  or any other user key). 
     Referring to  FIGS. 12 through 23 , the lock  1  is programmed to operate with the first user key  140 , since the change balls from the 1 st , 2 nd  and 6 th  pin positions correspond with raised contour positions  41 ,  42  and  46  on first user key  140 . When programming key  540  is inserted into the keyway as shown in  FIG. 12 , the programming contour positions  64  (see  FIG. 3 ) across each and all of the contour positions of the programming key causes all the change balls  326 ,  426  and  526  disposed in the corresponding pin chambers to be raised out of the tumbler chambers  13  and substantially into the driver chambers  24 . It can be observed that none of the hardware (drivers  27 , tumblers  25  or change members  26 ) span across the shear line  80  of any of the pin chambers. Thus, when the programming key  540  rotates the plug to the programming position shown in  FIG. 13 , the change balls  326 ,  426  and  526  become isolated within the corresponding driver chambers  24 . When the rotating plug  10  arrives at the programming position shown in  FIGS. 13 and 14 , the change balls  126 ,  226  and  626  are disposed in the respective retainer cavities  56 , and the change balls  326 ,  426  and  526  disposed in the driver chamber  24  and isolated from the retainer cavities  56  by the cavity carriage  50  in its non-aligned position. 
     When employing a programming key to reprogram the lock, the lock is typically first placed into a reset position, by moving all of the change balls into their corresponding retainer cavities  56 . As shown in  FIGS. 15 , this is accomplished by manipulating the cavity carriage  50 , typically by depressing the end  53  rearward against the biasing spring  51 , to place the cavity carriage into its first, aligned position, and each of the retainer cavities into alignment and communication with the corresponding driver chambers. In this position, the remaining change balls  326 ,  426  and  526  are forced by driver springs  28  down into the retainer cavities  356 ,  456  and  556 . 
     When the cavity carriage is released back to its biased second, non-aligned position shown in  FIG. 16 , the lock is said to be in a “lockout” configuration. If the programming key  540  were to be removed in this configuration, then none of the authorized user keys of the set of keys would be able to operate the lock, because each of the user keys has at least one contour position that is a lowered contour position. Use of that user key when the lock is in the lock-out configuration will fail to raise the drive corresponding to that lowered contour position to a height sufficient to align with the shear line  80 . Rather, that driver will span across the shear line, and the plug will not rotate, and hence the lock will not operate. 
     From the lockout configuration shown in  FIG. 16 , the lock can be temporarily returned to the null configuration, mentioned previously and shown in  FIG. 2 . This is accomplished by bringing the cavity carriage  50  into its first alignment position with respect to the driver chambers  24 , and using a change tool  60 , also shown in  FIG. 3 , to raise each and all of the change balls  26  to a position where at least their centerlines are displaced out of their corresponding retainer cavities  56  and into the driver chambers  24 . In  FIG. 17 , the tip  66  of the change tool  60  is placed into the slot  54  at the end  53 . The tip  66  is shown having a first leading beveled portion and a second trailing beveled portion, configured to raise a change member a first axial distance and a second axial, respectively, within the retainer cavity. The leading beveled portion has a somewhat blunted profile, to transfer longitudinal force from the change tool into both longitudinal and vertical (lifting) force vectors upon the curved surface of the change ball or other change member. As the change tool  60  is manipulated rearwardly, the leading bevel portion of the tip  66  first engages change ball  126  disposed in its retainer cavity  156 , and the vertical or lifting force vector partially raises the change ball within retainer cavity against the inside wall of the cylindrical bore  19 , while the longitudinal force vector acts upon the change ball  50  within the retainer cavity to move the cavity carriage  50  longitudinally in the rearward direction, against the biasing force of the spring  51 , until the cavity carriage  50  arrives at its first, aligned position with respect to the driver chambers shown in  FIG. 18 . Typically, a stop means, such as the pin  59  in groove  57  of cavity carriage  50 , can be provided to prevent the cavity carriage  50  from moving further rearward beyond the aligned position. Once the cavity carriage has engaged the stop means, further manipulation of the change tool  60  into the length of the slot  54  forces the tip  66  followed by the blade  51  to both be inserted into and to occupy the space within each and all of the retainer cavities  56 , and to scoop and lift each and all of the change balls  26 , in succession, up and onto the top edge  65  of the change tool  60 . The height of the top edge  65  raises each and all of the change balls  26  to a height where at least the centerline of the ball is raised into the corresponding driver chamber  24 , as shown in  FIG. 19 . With the change tool  60  fully inserted into the slot  54  and occupying the space within each retainer cavity  56 , the manipulation and rearward force applied to the change tool  60  can be released, whereby the biasing spring  51  forces the cavity carriage  50  with the inserted change tool  60  to its non-aligned position, as shown in  FIG. 20 . In this position, as shown in  FIGS. 21 and 22 , the change tool  60  can be withdrawn, whereby the change balls  26  remain isolated in the driver chambers from the retainer cavities  56 , since the cavity carriage  50  is in its non-aligned position and the change balls  26  rest in the openings  16  of the plug and upon the peripheral surface of the cavity carriage  50  disposed between the adjacent retainer cavities  56 . 
     It can be understood, viewing  FIG. 22 , that if the user were to depress the button end  53 , the cavity carriage  50  would be manipulated axially into its first, aligned position, and all of the change balls  26  would move back into their corresponding retainer cavities  56 . 
     To reprogram the lock for use with a second user key, the plug is rotated back to the key insertion position shown in  FIG. 23 , placing all the change balls  26  back into their corresponding pin chambers. Upon removal of the programming key  540 , the lock now has been returned to the null position, with all the change balls  26  back into their corresponding pin and tumbler chambers, as shown in  FIG. 2 . 
     From the null lock configuration, any of the authorized user keys of the set of keys including the first user key  140  (again) and second user key  240  can be inserted into the lock and manipulated to the programming position to reconfigure the lock for that particular user key.  FIGS. 24-28  show the steps for configuring the lock from the null configuration, where either user key can be inserted and the plug rotated, to a configuration for operation by the second user  240  key, wherein the first key  140  can not operate the lock. In  FIG. 24 , the raised contour positions on user key  240  raise the change balls in the first, fourth and sixth pin chambers into the corresponding driver chambers, where they are isolated when the plug  10  is rotated to the programming position shown in  FIG. 25 . The change balls  126 ,  426  and  626  remain in the driver chambers because the cavity carriage  50  is biased to its non-aligned position within the plug. Upon manipulation of the button  53  rearward, as shown in  FIG. 26 , the retainer cavities  56  align with the driver chambers  24 , and the force of the driver springs  28  move the change balls  126 ,  426  and  626  into the corresponding retainer cavities of the cavity carriage  50 , as shown in  FIG. 27 . The change balls  126 ,  426  and  626  can be isolated into their corresponding retainer cavities  156 ,  456  and  656  either by releasing the force on the cavity carriage  50  to allow movement to its non-aligned position, or by rotating the plug back to the key insertion position, shown in  FIG. 28 , while depressing the end  53 . Once returned to the key insertion position, the lock is then said to be configured for the second user key  240 , with change balls  126 ,  426  and  626  disposed in their second positions within the corresponding retainer cavities, and change balls  226 ,  326  and  526  disposed in the corresponding pin chambers. 
     A second embodiment of the lock is shown in  FIGS. 29-34 . The embodiment is otherwise the same as the first embodiment, except that the cavity carriage  150  of the second embodiment moves within the bore  19  in rotational movement, instead of the axial movement of the first embodiment. The cavity carriage  150 , shown in  FIG. 29 , has a cylindrical shaped body  152  that is configured to be disposed and moveable rotationally within a cylindrical bore  19  formed in the plug  10 . The cavity carriage  150  has a plurality of retainer cavities  156  formed into the surface of the cavity carriage and along its length and a slot  154 , similar to those described for the first embodiment of cavity carriage  50 . The cavity carriage  150  rotates within the bore  19  between a first position, shown in  FIGS. 30 and 33 , wherein the plurality of retainer cavities  156  are aligned axially with the corresponding plurality of driver chambers  24  when the plug  10  is rotated to the programming position, and a second position, shown in  FIGS. 31 and 32 , wherein the corresponding plurality of retainer cavities  156  arc not aligned with the plurality of driver chambers  24 , typically wherein the openings into the retainer cavities face or are oriented within the body of the plug  10 . Alignment of the retainer cavities and the driver chambers typically means that the openings register to permit movement of the change ball therebetween. When not in alignment, the central axes of the respective driver chambers and retainer cavities are typically non-parallel, and the respective openings of the retainer cavities are not coextensive with the driver chamber. 
     The cavity carriage  150  has a rounded groove  157  formed in the outer periphery of the cavity carriage  150 , extending radially about 90° around the circumference of the carriage  150 . The groove  157  is configured to receive the securing pin  58 , shown in  FIG. 29 , that passes through and is partially retained in a securing hole  59  formed in the plug  10 . The relationship between the securing pin  58  and the groove  157  is sliding, such that the portion of the securing pin  58  residing within the groove  157  restrains the cavity carriage  150  from longitudinal movement within the bore  19 , while permitting rotation of the carriage  150  within the bore  19  in a range of about 90°. 
       FIG. 30  is a sectional view of the lock of  FIG. 29 , taken through the cavity carriage  150 , showing the cavity carriage  150  rotated in a position where the retainer cavities  56  are in axial alignment with the openings  16  in the periphery of the plug  10 .  FIGS. 31 and 32  show the cavity carriage  150  within the bore  19  rotated to its second, non-aligned position, with the slot  154  oriented perpendicular to or away from the axis of the opening  16  in the plug periphery  12 .  FIG. 32  also shows the lock in a configuration wherein the programming key  540  has been inserted and rotated in the plug when all of the change balls  26  were originally in the corresponding pin chambers.  FIG. 33  shows the lock just after the cavity carriage  150  has been rotated within the bore  19  to its second or aligned position, wherein each of the retainer cavities  156  are aligned with and open to receiving the change balls  26  that are driven down out of the driver chambers  24  by the driver springs  28 , placing the lock into the reset configuration. The opening of the slot  154  in the end  153  serves as a convenient opening into which the tip  166  of the change tool  160 , or some other wedge means, can be inserted as a lever to rotate the cavity carriage  150  to the first communication position. Typically, the groove  157  and pin  58  cooperate so that the rotation to the communication position stops when the slot  54  is oriented parallel to the opening  16  in the plug periphery  12 . 
       FIG. 33  also illustrates the step of raising any of the change balls  26  from the retainer cavity  156  into the corresponding driver chamber  24 . The tip  166  of the change tool  160  is inserted into the end of the slot  154 , and then manipulated, as previously described for the first embodiment, to successively raise each of the change balls  26  out of the retainer cavities  156  as the change tool blade  161  is moved into and through each successive retainer cavity  156  along the length of the slot  154 . From this position, the change balls  26  can be isolated into the driver chambers  24  by moving the retainer cavities  156  out of alignment with the driver chambers  24 , either by rotating the plug  10  away from the programming position, or by manipulating the change tool  160  to rotate the cavity carriage  150  within the bore  19  away from the opening  16  in the plug periphery, as shown in  FIG. 31 . As explained earlier, movement of the change balls  26  back to the pin chambers places the lock back into a null configuration. 
     In a similar way, the lock of the second embodiment can be reset using the change tool  160  and the operable user key  40  when the lock is configured for operation by the operable user key  40 , such as the lock configuration for the second user key  240  shown in  FIGS. 27 and 28 . In that circumstance, all the change balls  126 ,  426  and  626  would be raised out of their respective retainer cavities  156  by the inserted change tool  160 , while the change balls  226 ,  326 , and  526  are already within their corresponding tumbler chambers  13 . 
     During normal lock operation and use, the cavity carriage  150  would be positioned in its non-aligned position shown in  FIGS. 31 and 32 , to avoid incidental keying and accidental reconfiguring of the active change balls disposed in the pin chamber, into their corresponding retainer cavities  156 . The cavity carriage  150  would only require rotation to its aligned position, shown in  FIGS. 29 and 33 , when the user intended to move change members  26  into, or out of, the corresponding retainer cavities  156 , for re-programming the lock. 
     A third embodiment of the lock is shown in  FIGS. 35-39 . The embodiment is otherwise the same as the first embodiment, except that the cavity carriage  250  of the third embodiment cooperates with a stationary, integral change tool  260  disposed within the plug  10 . The cavity carriage  250 , shown in  FIG. 35 , has a cylindrically-shaped body  252  that is configured to be disposed and moveable within the cylindrical bore  19 . Although the illustrated cavity carriage  250  and its complementary-shaped bore  19  are shown having a circular cross sectional shape, other shapes such as rectilinear and oval can be used. 
     The cavity carriage  250  has a plurality of aligned retainer cavities  256  formed into the surface and along its length. The retainer cavities  256  are of substantially the same size, and have a pitch between adjacent retainer cavities  256  equivalent to the pitch of the driver chambers  24 . The retainer cavities  256  differ however from the retainer cavities  56  of the earlier embodiment, in that the retainer cavity  256  has a centerline angled from vertical or orthogonal (perpendicular to the axis), forming sidewalls of elliptical or oval cross section. The retainer cavities  256  slant slightly rearward, away from the end  253 , as the cavity descends from its opening  297  toward the centerline  400  of the body  252  to a bottom  299 , as shown in  FIGS. 36   a  and  36   b . The retainer cavity  256  therefore has a slanted or angled sidewall  298 , relative to the centerline  400  of the body  252 . The shape of the retainer cavity  256  is conveniently round, although other shapes are usable. The diameter or minimum size of the retainer cavities  256  is at least slightly larger than the diameter or maximum size of the change ball  26 . 
     The cavity carriage body  252  also has a slot  254  formed into the body  252 , oriented substantially parallel to, and typically along, the axial centerline  400 . The slot  254  is illustrated as extending from inboard of the front end  253 , toward and through a portion of the plurality of retainer cavities  256 , and through the rear end  289  of the body  252 . The slot  254  extends forward toward the front  53  sufficiently to accommodate the stationary tool  260  when the cavity carriage  250  is depressed, as shown in  FIG. 38 . The change slot  254  has a radial depth that is greater than the depth of the bottom  299  of the retainer cavities  256 , to also accommodate the stationary tool  260 , described below. The change slot  254  is typically configured with a minimum width that accommodates the width of the stationary tool  260 , and is typically about 0.020 inches (about 0.50 mm) or less. 
     Cooperating with the slanted retainer cavities  256  and disposed within the change slot  254  is the stationary tool  260 . The stationary tool  260  is configured as a shaped blade that is disposed within the change slot  254 , and has a plurality of rectilinear pockets  261  defined by teeth  262 , each tooth having a front-facing edge  263  and a rear-facing edge  264 . The stationary tool  260  is biased against the rear wall  219  of the bore  19  by a biasing means shown as a spring  251  that is captured between the flange  265  at the rear end of the stationary tool  260 , and the rear face  289  of the cavity carriage  250 . The spring  251  biases the cavity carriage  250  towards its second, non-aligned position, shown in  FIG. 37 , and is compressed when the cavity carriage  250  is manipulated rearward to its first, aligned position shown in  FIG. 38 . The biasing force of the spring  251  disposes the stationary tool  260  in a position wherein each of the pockets  261  align with and are open toward the corresponding driver chambers  24  when the plug is in the programming position, as shown in each of the  FIG. 37-39 . 
     The cavity carriage  250  moves within the bore  19  between a first position wherein the openings  297  to the plurality of slanted retainer cavities  256  are aligned with the plurality of driver chambers  24 , shown in  FIG. 38 , when the plug  10  is rotated to the programming position, and a second position wherein the openings  297  to the slanted retainer cavities  256  are out of alignment with the plurality of driver chambers  24 , shown in  FIG. 37 , when the cavity carriage  250  has been biased within the bore  19  toward the front of the plug by spring  251 . The cavity carriage  250  can move longitudinally between the first and second positions substantially independent of the rotational position of the plug  10  within the housing  20 . 
     The cavity carriage  250  has an elongated flat  257  that cooperates with the securing pin  58  disposed in the hole  59  to control the range of longitudinal movement of the cavity carriage  250  between its first and second longitudinal positions, as described for the first embodiment. 
     One can see that pressing the cavity carriage rearward against compressing spring  251  brings the retainer cavities  256  into alignment with the openings  16  in the periphery  12  and the driver chambers  24 . If a change ball  26  is disposed within the driver chamber  24  when the carriage  250  is in the second, non-aligned position, as shown in  FIG. 37 , the rim edge  294  defining the opening  297  blocks the change ball  26  from passing into the slanted retainer cavity  256 . In that same position, when the carriage  250  is moved to the first, aligned position, shown in  FIG. 38 , the rim edge  294  moves away from the opening  16  in the plug, allowing the change ball  26  to begin passing through the opening  16 , and down along the slanted wall  298  of the retainer cavity  256 . As the force F is released, and the carriage  250  is biased forward to the non-aligned position shown in  FIG. 39 , the descending change ball  26  will continue passing through the opening  16  in the plug, both within the pocket  261  between adjacent teeth  262  of the stationary tool  260 , and down along the slanted sidewalls  298  of the retainer cavity  256 , ultimately passing completely to the bottom  299  within the retainer cavity  256  and to the bottom of the pocket  261  of the stationary tool  260 . 
     If a change ball  26  is disposed within the bottom  299  of the slanted retainer cavity  256  as shown in  FIG. 39 , then movement out of the retainer cavity is accomplished by manipulating the carriage  250  rearward, as shown in  FIG. 38 . The slanted sidewalls  298  exert both longitudinal and vertical (upward) force upon the change ball  26 , causing the change ball to move against and up along the forward surfaces  263  of teeth  262 , eventually emerging through the opening  297  of the retainer cavity  256  and opening  16  in the periphery of the plug, and into driver chamber  24 , as shown in  FIG. 38 . To isolate the change balls  26  in the corresponding driver chambers  24 , the plug  10  is rotated away from the programming position while depressing or holding the carriage  250  in its aligned position, since merely releasing the carriage  250  would cause the change balls  26  to be driven back down into the corresponding retainer cavities  256 . 
     In alternative embodiments of the present invention, the bore  19  and the cavity carriage  50 ,  150  and  250  can be disposed on the opposed side of the plug, whereby rotation of the plug to the programming position is in the counter clockwise direction. 
     Another embodiment of the lock is shown in  FIG. 40 . The embodiment is otherwise the same as the first embodiment and/or the third embodiment, except that the cylindrical bore  319  for the cavity carriage  350  is formed to intersect the periphery  12  of the plug, thereby exposing a portion of the cavity carriage  350  directly through the periphery  12  of the plug. The portion of the body  252  of the cavity carriage  350  exposed through the periphery  12  of the plug is shaped to be flush with the periphery so that the plug and cavity carriage assembly can rotate within the housing. 
     In other embodiments of the present invention, a method is provided for using the lock by providing a means for rapidly changing the internal configuration of the drivers, tumblers and change balls of the lock to program the lock to operate, typically exclusively, with one user key of a set of user keys. The method of using the rapidly-changeable lock does not require disassembly, or removal of the plug from the housing, or re-pinning of the tumbler pins. The method involves inserting a programming key into the keyway of the lock that is configured to operate with a first user key. The inserted programming key provides for rotation of the plug in an opposite direction, to a programming position. The programming key also provides that any change ball disposed within the pin chambers is forced up into its respective driver chamber, and is subsequently deposited within its respective retainer cavity. In the programming position, the change balls remain isolated in the driver chambers. Next, the cavity carriage is manipulated, depending upon the embodiment used, either by depressing or rotating, or otherwise moving, the cavity carriage from its non-communicating position, into a communicating position, allowing the change ball to move from the driver chamber into the retainer cavity. 
     The method can also include moving the change member or ball from the retainer cavity back to the pin chamber, substantially as described in the above description. 
     The embodiments of a programmable lock assembly can be used in a variety of locking devices. These locking devices include both commercial and residential locks, and include by example, knob locks, deadbolt locks, and padlocks. The operation of a typical knob lock can include the use of the operable key both to unlock and lock the door knob by turning a latch that is secured to the latch end of the plug, or to provide only for unlocking of the latch. In the later embodiment, the latch typically unlocks the door knob, which can then turn or rotate by hand, and thereby operate an elongated bolt that engages and disengages the jamb of the door or other object that is being locked. The operation of a typical dead-bolt lock includes the use of the operable key to unlock and rotate a latch that drives an elongated bolt to engage and disengage the jamb of the door or other object that is being locked. These locks are well-known to one skilled in the art. 
     An advantage of the present lock assembly that employs a means for isolating the retainer cavities from the driver chambers when the plug is in the programming position, is that the programming key can operate as a master key. Master keys are used to operate or “open” the lock and unlatch the door or other device being secured closed by the lock, regardless of the user configuration of the lock and of which user key is operable. In the now conventional lock embodiments described in the aforementioned US Patent Publication 2004-0221630, a master shim can be disposed in the driver/tumbler pin stack directly beneath the change member. The master shim is shaped as a flattened disc, typically having a thickness less than its diameter, and typically having a diameter substantially the same as the diameter of the driver pins. When a master key is inserted, the top edge of the tumblers are raised to the shear line, and any master shim and any and all change members in the pin stack positioned above the tumbler are raised into the driver chamber. When the lock is operated and the plug is rotated to the programming position, the master shims, due to their larger size, block the change members in the driver chambers from dropping into the corresponding retainer cavities. Without the master shims, use of the master key would place the lock into the “lockout” configuration. Use of the master shims allows the master key to open any lock in a particular facility system without reconfiguring the driver/tumbler stack of the lock. 
     However, in the lock embodiments of the present lock assembly, the isolating means in its first position prevents the spontaneous movement of a change member or ball from moving from the driver chamber into the corresponding retainer cavity. Therefore, even though the programming key raises all of the change members in the pin chambers above the shear line, and as such acts as a master key, the lock will not spontaneously be placing into lockout configuration when the plug is rotated to the programming position, due to the isolating means. Manipulating or placing the isolating means into its second position selectively allows the change members to be moved into the retainer cavities to place the lock into its lock-out position. 
     Nevertheless, in alternative embodiments of the lock assembly, one or more master pins or shims can be installed within one or more of the plurality of pin chambers, typically one or more of the most rearward pin chambers. The addition of one or more master pins in the lock assemblies adds additional master keying capacity. 
     While the invention has been disclosed by reference to the details of preferred embodiments of the invention, it is to be understood that the disclosure is intended in an illustrative rather than in a limiting sense, as it is contemplated that modifications will readily occur to those skilled in the art, within the spirit of the invention and the scope of the appended claims.