Abstract:
A locking device for controlled, reversible security using a control key to set the lock&#39;s accessibility to multiple individual keys, thus providing complete control of security. The control key has hierarchy over the individual key(s). Rotating the control key from the first to a second position prevents the core from being actuated by the individual key(s), thus activating a blocking function by which the lock can only be operated by the control key. Returning the control key from the second position back to the first position allows the control key to be removed ( the blocking function is still active). When the control key is rotated from the first to a third position, the core can be operated by the individual key(s), thus inactivating the blocking function. Returning the control key from the third position to the first position allows removal of the control key (blocking function remains inactive).

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    The present application derives priority from U.S. provisional application No. 60/383,021 for “CONTROLLED ACCESS LOCK”; Filed: May 23, 2002; Applicant: Thomas, M. Koluch. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The present invention relates to locking devices for providing secure entry by use of keys and, more particularly, to a controlled-access lock that allows dual-control by a user key as well as a control key to give complete owner control and security within an immediate time frame.  
           [0004]    2. Description of the Background  
           [0005]    There is a commercial need to provide controlled key-access security using a control key that sets a lock&#39;s accessibility to individual keys, thus providing the owner/operator of a premises with complete control of security. For example, if a tenant key is lost or stolen, the landlord typically must have the door lock replaced at significant expense. This situation is especially acute in multiple-unit buildings such as apartments and office buildings. Electronic key systems now exist to allow an owner to selectively permit one key card to open each lock and not the other key cards. However, these systems are cost prohibitive for many business and residential applications. There currently is no mechanical lock equivalent to provide a cost-effective solution.  
           [0006]    There have, however, been a few prior efforts to develop a mechanical controlled-access lock. For example, pin tumbler locks which may be rekeyed without removing the tumblers, and therefore rekeyed without a locksmith, are known. U.S. Pat. No. 1,565,556 of Fremon, issued Dec. 15, 1925, and U.S. Pat. No. 2,603,081, of Pelle, issued Jul. 15, 1952 disclose locks which must be removed from the lock assembly in which they have been assembled in order to effect rekeying. Therefore, while those locks may not require a locksmith for rekeying, rekeying would not ordinarily be attempted by someone who is not mechanically inclined. U.S. Pat. No. 5,921,121 to Tang issued Jul. 13, 1999 shows an adjustable key-type spring pin lock cylinder. By turning an adjusting lever ( 10 ) the owner can select one of two keys to open the lock. A lock which may be rekeyed from the exterior by a reset key which adjusts the positioning of the tumblers is disclosed, for example, in U.S. Pat. No. Re. 28,319 of Kerr, which was reissued on Jan. 28, 1975 (original patent issued on Sep. 4, 1973). The &#39;319 Kerr Patent discloses an axial pin tumbler lock which includes a number of pin tumbler sets that extend circumferentially about the lock, each of the tumbler sets including three axially-extending tumblers. One set of circumferentially-extending tumblers is rotated relative to the other two sets by the reset key to form new combinations of three tumblers for each tumbler set, thereby rekeying the lock. The reset key must be inserted into the lock in the same angular position relative to the lock that it was in when it was last withdrawn from the lock, otherwise the lock can not be rekeyed. In order to facilitate proper introduction of the reset key, the &#39;319 Kerr Patent suggests that the front of the lock be marked with indicia to identify the positions of the axial tumbler sets. However, such indicia may distinguish the exterior appearance of the lock from a non-rekeyable lock of the same type and thereby suggest that the lock may be re-keyed.  
           [0007]    All of the foregoing prior art examples require modification of the entire lock or some special outward indica. Also, the size of the existing designs make their use in common padlocks prohibitive. Furthermore, the control key merely activates the blocking or re-keying mechanisms in these other designs as opposed to actually opening the lock, and thus control keying is extremely limited in the existing patented designs.  
           [0008]    It would be greatly advantageous to provide a main body lock assembly that can be used in existing commercial and residential locks and padlocks containing removable main bodies that allow controlled, reversible security using a control key to set the lock&#39;s accessibility to multiple individual keys. The control key should act to limit the lock&#39;s accessibility, but remain completely functional in operating the lock at all times.  
         SUMMARY OF THE INVENTION  
         [0009]    It is, therefore, an object of the present invention to provide a main body assembly for commercial and residential locks and padlocks that allows controlled, reversible security using a control key to set the lock&#39;s accessibility to multiple individual keys, thus providing the owner/operator complete control of security.  
           [0010]    It is another object to provide a main body assembly for commercial and residential locks and padlocks as described above that simplifies installation, thereby allowing a broad range of existing locks to be retrofitted without necessitating a total lock replacement.  
           [0011]    It is another object to provide a main body assembly for commercial and residential locks and padlocks as described above in which the control key serves to limit the lock&#39;s accessibility, and yet remains completely functional in operating the lock itself.  
           [0012]    In accordance with the above-described objects, disclosed herein is a configuration for a locking device for controlled, reversible security using a control key to set the lock&#39;s accessibility to multiple individual keys, thus providing complete control of security. The control key has hierarchy over the individual key(s). Rotating the control key from the first to a second position prevents the core from being actuated by the individual key(s), thus activating a blocking function by which the lock can only be operated by the control key. Returning the control key from the second position back to the first position allows the control key to be removed ( the blocking function is still active). When the control key is rotated from the first to a third position, the core can be operated by the individual key(s), thus inactivating the blocking function. Returning the control key from the third position to the first position allows removal of the control key (blocking function remains inactive).  
           [0013]    Two embodiments of the locking device are disclosed. Both embodiments are based on a main body assembly that is uniform in size to match existing assemblies, thereby allowing retrofit of existing locks. In both embodiments, the lock can be operated by multiple “A” or individual key(s), or by a “Z” key, which is a control key. These keys are inserted and removed from a core with a cylinder in a first position. The Z key has hierarchy over the A key(s). Rotating the Z key from the first to a second position prevents the core from being actuated by the A key(s), thus activating a blocking function. At this point, the lock can only be operated by the Z key. Returning the Z key from the second position back to the first position allows the Z key to be removed from the core (the blocking function is still active). When the Z key is rotated from the first to a third position, the core can be operated by the A key(s), thus inactivating the blocking function. Returning the Z key from the third position back to the first position allows for removal of the Z key from the core (blocking function remains inactive).  
           [0014]    The preferred embodiment accomplishes the foregoing with a main body assembly including a shell-housing, a first set of tumblers and a second set of tumblers all loaded into corresponding bore(s) in the shell, a stationary drive pin, and a cylinder including a core and a multi-piece sleeve. This allows use of multiple individual keys and a single control (or master) key. An individual key inserted into the core aligns the gaps (or breaks) between the first tumblers and the second tumblers with a first shear line allowing rotation of the core and operation of the lock. When the control key is inserted into the core it aligns the gaps/breaks between the first tumblers and the second tumblers with a second shear line such that rotation of the control key to a first position allows for insertion and removal of the individual keys, and to a second position activates a blocking function preventing use of the individual keys, and to a third position that disables the blocking function. An alternate embodiment is also disclosed that is based on the operations of locking pins. Both embodiments are easily re-keyable.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]    Other objects, features, and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiment and certain modifications thereof when taken together with the accompanying drawings in which:  
         [0016]    [0016]FIG. 1 is a part-sectional view of the main body according to a preferred embodiment of the present invention with blocking function, at the front, inactivated in first position.  
         [0017]    [0017]FIG. 2 is a part-sectional view of the main body of FIG. 1 with blocking function, at the rear, inactivated in first position.  
         [0018]    [0018]FIGS. 3A and 3B are a bottom view and end view, respectively, of the main body of FIGS. 1 &amp; 2 showing one stationary drive pin.  
         [0019]    [0019]FIG. 4 is a side view of the cylinder with blocking function, at the front, inactivated.  
         [0020]    [0020]FIGS. 5A and 5B are a side view and perpendicular sectional view, respectively, of the core uniformly recessed across all bores with the blocking function at the front.  
         [0021]    FIGS.  6 A-D are a top view, bottom view and end view, respectively, of the multi-piece sleeve.  
         [0022]    [0022]FIG. 7 is an isometric view of the top portion of the multi-piece sleeve.  
         [0023]    [0023]FIG. 8 is a part-sectional view with A key inserted, of the main body of FIGS.  1 - 3 B, with blocking function inactivated in first position.  
         [0024]    [0024]FIG. 9 is a part-sectional view with control key (Z) inserted, of the main body of FIGS.  1 - 3 B, with blocking function inactivated in first position.  
         [0025]    [0025]FIG. 10 is a part-sectional view as shown in FIG. 9 with blocking function activated in first position.  
         [0026]    [0026]FIG. 11 is a bottom view of the multi-piece sleeve bottom portion with the blocking function inactivated in the first position.  
         [0027]    [0027]FIG. 12 is a bottom view of the multi-piece sleeve as shown in FIG. 11, with the blocking function partially activated and approaching the second position.  
         [0028]    [0028]FIG. 13, is a bottom view of the multi-piece sleeve as shown in FIG. 12, with blocking function activated and in the second position.  
         [0029]    [0029]FIG. 14, is a bottom view of the multi-piece sleeve as shown in FIG. 13, with blocking function activated and approaching the first position.  
         [0030]    [0030]FIG. 15, is a bottom view of the multi-piece sleeve as shown in FIG. 14, with blocking function activated and in the first position.  
         [0031]    [0031]FIG. 16 is a part-sectional view with A key inserted, as shown in FIG. 10, with blocking function activated in first position.  
         [0032]    [0032]FIG. 17 is a bottom view of the multi-piece sleeve bottom portion with the blocking function activated and in the first position.  
         [0033]    [0033]FIG. 18 is a bottom view of the multi-piece sleeve bottom portion as shown in FIG. 17, with the blocking function partially activated and approaching the third position.  
         [0034]    [0034]FIG. 19 is a bottom view of the multi-piece sleeve bottom portion as shown in FIG. 18, with the blocking function inactivated and in the third position.  
         [0035]    [0035]FIG. 20 is a bottom view of the multi-piece sleeve bottom portion as shown in FIG. 19, with the blocking function inactivated and approaching the first position.  
         [0036]    [0036]FIG. 21 is a bottom view of the multi-piece sleeve bottom portion as shown in FIG. 20, with the blocking function inactivated and in the first position.  
         [0037]    [0037]FIGS. 22A and 22B are a side view and perpendicular sectional view, respectively, of the core uniformly recessed across all bores with the blocking function at the rear.  
         [0038]    [0038]FIG. 23 is a part-sectional view with control key (Z) inserted, as shown in FIG. 2, with blocking function activated in first position.  
         [0039]    [0039]FIGS. 24A &amp; 24B are a bottom view and end view, respectively, of the multi-piece sleeve bottom portion (degree of rotation less than ±90 degrees).  
         [0040]    [0040]FIGS. 25A &amp; 25B are a bottom view and end view, respectively, of the main body showing two stationary drive pins.  
         [0041]    [0041]FIGS. 26A &amp; 26B are a top view and end view, respectively, of the multi-piece sleeve top portion showing a channel.  
         [0042]    [0042]FIGS. 27A, 27B,  27 C &amp;  27 D are a bottom view, top view and end view, respectively, of the multi-piece sleeve showing one bore.  
         [0043]    [0043]FIGS. 28A &amp; 28B are a side view and perpendicular sectional view, respectively, of the core with blocking function at the rear and showing a shorter longitudinal recess as compared to FIGS. 5A &amp; B.  
         [0044]    [0044]FIGS. 29A &amp; 29B are a top view and end view, respectively, of the top portion of the multi-piece sleeve  26  with the bore offset.  
         [0045]    [0045]FIGS. 30A &amp; 30B show the core as in FIGS. 28A &amp; 28B, with a blocking function that is offset.  
         [0046]    [0046]FIGS. 31A &amp; 31B are a bottom view and end view of the main body with the stationary drive pin offset compared to FIGS. 3A &amp; 3B and showing one stationary drive pin.  
         [0047]    [0047]FIGS. 32A &amp; 32B are a bottom view and end view of the main body, respectively, with the stationary drive pins offset compared to FIGS. 25A &amp; B and utilizing two stationary drive pins.  
         [0048]    [0048]FIGS. 33A, 33B and  33 C are a top view, bottom view and end view, respectively, of the single piece sleeve.  
         [0049]    [0049]FIGS. 34A, 34B and  34 C are a top view, bottom view and end view, respectively, of the single piece sleeve (degree of rotation less than ±90 degrees).  
         [0050]    [0050]FIGS. 35A and 35B are a side view and perpendicular sectional view, respectively, of the core uniformly recessed across all bores and through to the rear of the core with the blocking function at the front.  
         [0051]    [0051]FIGS. 36A, 36B and  36 C are a top view, bottom view and end view, respectively, of the single piece sleeve depicting a shorter longitudinal length as compared to FIGS.  33 A-C.  
         [0052]    [0052]FIGS. 37A, 37B and  37 C are a top view, bottom view and end view, respectively, of the single piece sleeve depicting a shorter longitudinal length as compared to FIGS.  34 A-C (degree of rotation less then ±90 degrees).  
         [0053]    [0053]FIGS. 38A &amp; 38B are a side view and perpendicular sectional view, respectively, of the core with blocking at the front showing a shorter longitudinal recess as compared to FIGS. 35A, B.  
         [0054]    [0054]FIGS. 39A and 39B are a side view and end view, respectively, of a core retaining pin.  
         [0055]    [0055]FIGS. 40A and 40B are a bottom view and end view, respectively, of the multi-piece sleeve&#39;s bottom portion (configuration of channel is mirror-image of FIGS.  6 A-D).  
         [0056]    [0056]FIGS. 41A and 41B are a bottom view and end view, respectively, of the single piece sleeve (configuration of channel is mirror-image of FIG. 33A-C).  
         [0057]    [0057]FIG. 42 is a part-sectional view of the main body according to an alternate embodiment of the invention with the blocking function inactivated in first position.  
         [0058]    [0058]FIG. 43 is an exploded part-sectional view of the rear portion of the main body as in FIG. 42 and the short, medium and long locking pins with the blocking function inactivated.  
         [0059]    [0059]FIG. 44 is a perpendicular sectional view in the first position with blocking function inactivated.  
         [0060]    [0060]FIG. 45 is a part-sectional view of the cylinder.  
         [0061]    [0061]FIG. 46, as shown in FIG. 42, has A key inserted with the blocking function inactivated in first position.  
         [0062]    [0062]FIG. 47, as shown in FIG. 46, has Z key inserted with the blocking function inactivated in first position.  
         [0063]    [0063]FIG. 48, as shown in FIG. 47, has the blocking function activated in first position.  
         [0064]    [0064]FIG. 49 is an exploded part-sectional view of the long, medium and short locking pins.  
         [0065]    [0065]FIG. 50 is a perpendicular sectional view with Z key inserted and rotated to the second position with the blocking function activated.  
         [0066]    [0066]FIG. 51, as shown in FIG. 46, has A key inserted with the blocking function activated in first position.  
         [0067]    [0067]FIG. 52 is a perpendicular sectional view in the first position with the blocking function activated.  
         [0068]    [0068]FIG. 53 is a perpendicular sectional view with Z key inserted and rotated to the third position with the blocking function inactivated.  
         [0069]    [0069]FIG. 54 is a perpendicular sectional view with A key inserted and rotated to the second position with the blocking function inactivated.  
         [0070]    [0070]FIG. 55 is a perpendicular sectional view in the first position with the blocking function inactive and showing a medium locking pin having detents.  
         [0071]    [0071]FIG. 56, as shown in FIG. 43, with the blocking function inactivated showing medium locking pin having detents.  
         [0072]    [0072]FIG. 57, as shown in FIG. 47, with the blocking function activated with medium locking pin having detents in first position. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0073]    A preferred main body assembly in accordance with the invention is shown in FIG. 1 and is designated generally by numeral  10 . The main body assembly includes a shell  12  that houses all of the components as presented in FIG. 1. The components are comprised of tumblers  14  and tumbler springs  16  housed in bores  18  in shell  12  (see also FIGS. 3A &amp; 3B), a stationary drive pin  20 , and a cylinder  22  (see also FIG. 4).  
         [0074]    As best seen in FIG. 4, the cylinder  22  is comprised of a core  24  encircled by a multi-piece sleeve  26 , the sleeve being a hollow cylindrical component comprised of at least two pieces: a top portion  36  and a bottom portion  42 . Referring back to FIG. 1, the core  24  houses a plurality of drive tumblers  28  in bores  30  which are machined into core  24 , and also houses a core retaining pin  31  (see also FIG. 5B). As seen in FIG. 5A, the core  24  is also defined by a keyslot  23  which accepts the keys (not shown). FIG. 5B is a side view of the core  24  which illustrates the recess in which multi-piece sleeve  26  is seated. Note that the upper recess closely conforms to the top sleeve portion  36 , but the lower recess is longer than the bottom sleeve portion  42  to provide room for a shift.  
         [0075]    Referring back to FIG. 1, the multi-piece sleeve  26  is separated from the core  24  by a first shear line  32 , and is separated from the main body  12  by a second shear line  34 . The sleeve upper portion  36  also has bores  38  (see FIGS. 6A &amp; 6B) to accept both the drive tumblers  28  and tumblers  14 .  
         [0076]    As seen in FIGS. 6C &amp; 6D and  7 , the multi-piece sleeve  26  has a guide channel  40  formed in one or both of the upper portion  36  and/or lower portion  42 , the channel  40  being shown in the lower portion  42  in the illustrated embodiment. The guide channel  40  further comprises an entrance/exit channel  44 ; ramps which are referred to as inclines  46 ,  48 ; and barriers  50 . Referring back to FIG. 1, the stationary drive pin  20  is fixed to the main body  12  and extends into the channel  40  of the multi-piece sleeve  26 .  
         [0077]    The operation of the controlled-access lock according to the present invention will now be described with reference to FIGS.  8 - 16 . The controlled-access lock allows dual-control by a user key A as well as a control key Z.  
         [0078]    As seen in FIG. 8, when the A key(s) is inserted into the core  24  (directly into an initial first position), it aligns the gaps/breaks between the drive tumblers  28  and the tumblers  14  with shear line  32 .  
         [0079]    As seen in FIG. 9, when the Z key is inserted into the core  24  (first position only), it aligns the gaps/breaks between both the drive tumblers  28  and tumblers  14  with shear line  34 . As the Z key is rotated the entire cylinder  22  (inclusive of core  24  and multi-piece sleeve  26 ) rotates. This is due to the gaps/breaks between both the drive tumblers  28  and tumblers  14  being in alignment with shear line  34  and not in alignment with shear line  32 .  
         [0080]    As seen in FIG. 10, rotation of the Z key to a second position causes the bottom portion of the multi-piece sleeve  42  to shift forward due to the stationary drive pin  20  engaging the incline  46  in the channel  40  of the bottom portion of the multi-piece sleeve  42 . Thus, use of the Z key to initiate this shift in the bottom portion of the multi-piece sleeve  42  activates the blocking function by which the A key(s) is inoperable.  
         [0081]    [0081]FIGS. 11, 12,  13 ,  14  and  15  depict the various positions of the stationary drive pin  20  with respect to the incline  46  as the Z key is rotated from the first position (see FIG. 11) to the second position (see FIG. 13) and back to the first position (see FIG. 15), thereby activating the blocking function.  
         [0082]    With combined reference to FIGS. 5A &amp; 5B, the lower recess in core  24  accepts the forward longitudinal shift in the bottom portion of the multi-piece sleeve  42  thereby rotatably locking the core  24  to the multi-piece sleeve  26  and making the A key(s) inoperable. Normally the A key(s) would be allowed to rotate the core  24 , however due to the activated blocking function, the A key(s) is inoperable as seen in FIG. 16.  
         [0083]    To deactivate the blocking function, the Z key is inserted in the core  24  (thereby aligning the gaps/breaks between drive tumblers  28  and tumblers  14  with shear line  34  (see FIG. 10) and is rotated from a first position to a third position and back to the first position. Rotating the Z key to the third position causes the bottom portion of the multi-piece sleeve  42  to slide back to the rear as seen in FIG. 9 (as before, the stationary drive pin  20  engages the incline  48  in the channel  40  of the bottom portion of the multi-piece sleeve  42 ), and this deactivates the blocking function.  
         [0084]    [0084]FIGS. 17, 18,  19 ,  20  and  21  show the position of the stationary drive pin  20  with respect to the incline  48  as the Z key is rotated from the first position (FIG. 17) to the third position (FIG. 19) and back to the first position (FIG. 21), thereby deactivating the blocking function.  
         [0085]    Afterward, the Z key is removed and the A key(s) is inserted aligning the gaps/breaks between the drive tumblers  28  and tumblers  14  to shear line  32  (FIG. 8). This allows the A Key(s) to rotate the core  24  thus operating the lock. Longitudinal movement of the bottom portion of the multi-piece sleeve  42  can only occur when the cylinder  22  is rotated (Z key). This is due to the stationary drive pin  20  engaging the inclines  46 ,  48  within the channel  40 . The inactivated blocking function is best seen in FIGS. 1, 11, with the cylinder  22  in the first position. Notice that the stationary drive pin  20  rests in the channel  40  with a barrier  50  to the rear of the stationary drive pin  20  thus isolating it from an adjacent channel  40 . This barrier  50  prevents unwanted forward longitudinal movement of the bottom portion of the multi-piece sleeve  42 , insuring that the blocking function remains inactive until otherwise determined by the rotation of the Z key. FIG. 17 shows the barrier  50  preventing unwanted longitudinal backward movement of the bottom portion of the multi-piece sleeve  42 , thus insuring that the blocking function remains active.  
         [0086]    [0086]FIGS. 11 and 17 also reveal an entrance/exit channel  44  which is used to remove the cylinder  22  from the main body  12 . Notice in FIG. 11 that the entrance/exit channel  44  is not exposed to the stationary drive pin  20 , thereby preventing removal of the cylinder  22 . FIG. 17 reveals that the entrance/exit channel  44  is exposed to the stationary drive pin  20  thus allowing for the cylinder&#39;s removal.  
         [0087]    It should be understood that the foregoing description is for illustrative purposes and obvious variations will occur to those skilled in the art. For example, the blocking function can be placed to the rear of the core  24  rather than the front of the core  24 . In this case, the bottom portion of the multi-piece sleeve  42  would have to slide to the rear of the core  52  to activate the blocking function as opposed to the front of the core  24 . This is easily accomplished by relocating the stationary driving pin  20  from position  54  to position  56  (see FIGS. 3A &amp; 3B). Also, a core  52  with a cutout located at the rear of the core  52  will have to be used as illustrated in FIGS. 22A and 22B which are a side view and perpendicular sectional view, respectively, of the core  52  uniformly recessed across all bores with the blocking function at the rear.  
         [0088]    [0088]FIG. 23 is a part-sectional view with control key (Z) inserted, as shown in FIG. 2, with blocking function activated in first position. FIG. 2 depicts the blocking function, at the rear, in the inactive state while FIG. 23 depicts the active state.  
         [0089]    For any lock, in which the ± rotation is less than ±90 degrees, such as padlocks, only one stationary drive pin  20  is needed, used in conjunction with either bottom portions of multi-piece sleeves  42 ,  60  (FIGS. 6C &amp; 6D). FIGS. 24A &amp; 24B are a bottom view and end view, respectively, of the multi-piece sleeve bottom portion (degree of rotation less than ±90 degrees). However, some main bodies will require the use of two stationary drive pins  20 ,  58  (each 180 degrees apart), depending on the amount of ± degrees (0 degree equals first position) that the Z key can be rotated. If the degree of rotation exceeds ±90 degrees (i.e. mortise cylinders), then two stationary drive pins  20 ,  58  (located in the main body  62 ) are necessary, used in conjunction with the bottom portion of multi-piece sleeve  42  (of FIGS. 6C &amp; 6D). FIGS. 25A &amp; 25B are a bottom view and end view, respectively, of the main body showing two stationary drive pins  20 ,  58 .  
         [0090]    Also, an additional channel  64  (including entrance/exit channel  66 ) formed into the top portion of the multi-piece sleeve  68  will be needed to accept the stationary drive pins  20 ,  58 . FIGS. 26A &amp; 26B are a top view and end view, respectively, of the multi-piece sleeve top portion showing a channel  64 . The reason for the second stationary drive pin  58  is to ensure that one of the two stationary drive pins  20 ,  58  will always be extended into the channel  40  of the bottom portion of the multi-piece sleeve  42  controlling its longitudinal movement at all times, regardless of the rotational position of the Z key.  
         [0091]    It is also noteworthy that the top portion of the multi-piece sleeve  36 ,  68 , as demonstrated, interacts with all of the drive tumblers  28  and tumblers  14  (FIGS. 26A &amp; 26B). This does not have to be the case. The same goal can be achieved by using a multi-piece sleeve  70  that interacts with a minimum of one drive tumbler  28  and tumbler  14 . For example, this can be achieved by using the multi-piece sleeve  70  of FIGS. 27A, 27B,  27 C &amp;  27 D, which are a bottom view, top view and end view, respectively, of the multi-piece sleeve  70  showing one bore  74 . FIGS. 28A &amp; 28B are a side view and perpendicular sectional view, respectively, of the matching core  72  with blocking function at the rear and showing a shorter longitudinal recess as compared to that of FIGS. 5A &amp; B. Additionally, the bore  74  in the top portion of the multi-piece sleeve  76  is shown at the center of the sleeve  76  (see FIGS. 27A &amp; 27B). The bore  78  can be offset from the center of the sleeve  80 , and FIGS. 29A &amp; 29B are a top view and end view, respectively, of the top portion of the multi-piece sleeve  80  with the bore offset. If the bore  78  is offset, the cut-out in the back portion of the core  82  (FIGS. 30A &amp; 30B) will also have to be offset the same amount to accommodate the longitudinal movement of the bottom portion of the multi-piece sleeve  84 . The stationary drive pins  20 ,  58  would also have to be relocated within the main body  83  to accommodate the offset, and FIGS. 31A &amp; 31B are a bottom view and end view of the main body with the stationary drive pin  20  offset (as compared to FIGS. 3A &amp; 3B). Note that FIGS. 31A &amp; 31B show one stationary drive pin, while FIGS. 32A &amp; 32B are a bottom view and end view of the main body  83 , respectively, with two offset stationary drive pins  20 ,  58 .  
         [0092]    Another design modification can be achieved by replacing the multi-piece sleeve with a single piece sleeve  86 ,  88  (FIGS. 33A, 33B and  33 C are a top view, bottom view and end view, respectively, of the single piece sleeve  86  with degree of rotation greater than ±90 degrees, and FIGS. 34A, 34B and  34 C are a top view, bottom view and end view, respectively, of the single piece sleeve with degree of rotation less than ±90 degrees) used with a matching core  90  (FIGS. 35A and 35B are a side view and perpendicular sectional view, respectively, of the matching core  90  uniformly recessed across all bores and through to the rear of the core with the blocking function at the front). Alternatively, single piece sleeves  86  or  88  can be used. FIGS. 36A, 36B and  36 C are a top view, bottom view and end view, respectively, of the single piece sleeve  92  depicting a shorter longitudinal length as compared to FIGS.  33 A-C. FIGS. 37A, 37B and  37 C are a top view, bottom view and end view, respectively, of the single piece sleeve  94  depicting a shorter longitudinal length as compared to FIGS.  34 A-C (degree of rotation less then ±90 degrees). In either case, the single piece sleeves  92  or  94  are used with a matching core  96  (FIGS. 38A &amp; 38B are a side view and perpendicular sectional view, respectively, of the matching core  96  with blocking at the front showing a shorter longitudinal recess as compared to FIGS. 35A, B). This modification still provides the same locking and unlocking functions as previously detailed. However, the single piece sleeve allows for the use of only one stationary drive pin  20  regardless of the control key&#39;s degree of rotation. The design modification is achieved by using a single piece sleeve  86 ,  88  along with a matching core  90  that interacts with all of the drive tumblers  28  and tumblers  14  (FIGS.  33 A-C,  34 A-C; note the depicted longitudinal slot  98  that accommodates all drive tumblers  28  and tumblers  14 ). The same can also be achieved by using a single piece sleeve  92 ,  94  with a matching core  96  that interacts with a minimum of one drive tumbler  28  and tumbler  14  (FIGS.  36 A-C,  37 A-C, note the longitudinal slot  100  that accommodates one drive tumbler  28  and tumbler  14 ). Thus, although a separate single piece sleeve would be required to accommodate either a less than or greater than ±90 degree of rotation, the matching core would not require modification to accommodate the rotational requirements. (Note: FIGS.  35 A-B and  38 A-B show cores  90 ,  96  with the blocking function to the front of the cores  90 ,  96 ). The cores  24 ,  52 ,  72 ,  82 ,  90  and  96  used in the previous examples utilize a core retaining pin  31 , and FIGS. 39A and 39B are a side view and end view, respectively, of a core retaining pin  31 . The core retaining pin  31  prevents forward longitudinal movement of the core. It also captures the single piece sleeve  86 ,  88 ,  92  and  94  preventing rear longitudinal movement.  
         [0093]    All previous examples refer to the fact that first position allows for insertion and removal of the keys, that the second position activates the blocking function and that the third position disables the blocking function. These positions do not specify direction of rotation (i.e. clockwise, counterclockwise). The direction of rotation (blocking function active or inactive) can be reversed by substituting the bottom portion of the multi-piece sleeve  42  (see FIGS. 6C &amp; 6D) with a sleeve  102  having a channel design that is a mirror image. FIGS. 40A and 40B are a bottom view and end view, respectively, of the multi-piece sleeve&#39;s bottom portion in which the configuration of channel  40  is the mirror-image of FIGS. 6C &amp; 6D. Likewise, for the single-piece sleeve  86  of FIGS.  33 A-C, the direction of rotation (blocking function active or inactive) can be reversed by substituting the single piece sleeve  86  (see FIGS.  33 A-C) with a sleeve  104  having a channel design that is a mirror image. Thus, FIGS. 41A and  41 B are a bottom view and end view, respectively, of a single piece sleeve  104  in which the configuration of channel  40  is the mirror-image of that of FIGS.  33 A-C.  
         [0094]    Rather than a multi-piece sleeve  26  with both upper and lower portions  36 ,  42  as described above, FIGS.  42 - 57  illustrate an alternate embodiment that is based on the operations of locking pins. The alternate embodiment includes a main body assembly as shown in FIG. 42 designated generally by numeral  110 . FIGS. 42, 43 and  44  depict a longitudinal and transverse view, respectively, of the main body  112  revealing all components. The components housed by the main body  112  include tumblers  114 , tumbler springs  116 , stationary driver  118 , stationary driver retainer  120  and cylinder  122 . The cylinder  122  consists of a sleeve  124  and core  126  (FIG. 45). The core  126  houses the drive tumblers  128 , long locking pin  130 , detent pin  132 , detent pin spring  134 , detent pin sleeve  136  and the detent pin retainer  138 . The core  126  is separated from the sleeve  124  by a shear line  140  (FIG. 42). The sleeve  124  is a hollow cylindrical component (having a smaller inside diameter at the rear) which houses the short locking pin  142 , medium locking pin  144  and is separated from the main body  112  by a second shear line  146 . The sleeve  124  has a channel cut into its rear section. The stationary driver  118  is fixed to the main body  112  (held in place by the stationary driver retainer  120 ) and extends into the channel of the sleeve  124  (FIG. 44).  
         [0095]    When the A key(s) is inserted into the core  126  (first position only), it aligns the gaps/breaks between the drive tumblers  128  and the tumblers  114  with shear line  140  (FIG. 46). When the Z key is inserted into the core  126  (first position only), it aligns the gaps/breaks between both the drive tumblers  128  and tumblers  114  with shear line  146  (FIG. 47). With the Z key still inserted into the core  126  and rotated to the second position, the core  126  and sleeve  124  (cylinder  122 ) rotate together. This is due to the gaps/breaks between both the drive tumbler  128  and tumblers  114  aligning with shear line  146  and not aligning with the second shear line  140  (FIG. 48). The rotation of the Z key to the second position causes the locking pins  148  (FIG. 49) to shift, thus extending them through shear line  140  located between the core  126  and the sleeve  124  (FIGS. 48, 50). This shift then locks the core  126  and sleeve  124  together (FIG. 48) thus activating the blocking function. Rotating the Z key from the second position back to the first position keeps the blocking function activated and allows for the removal of the Z key and insertion of the A key(s) into the core  126  (FIGS. 51, 52). With the A key(s) inserted, the gaps/breaks between the drive tumblers  128  and tumblers  114  are aligned with shear line  140  (FIG. 51). Normally, the A key(s) would be allowed to rotate the core  126 , but due to the blocking function being activated, the A key(s) is inoperable (FIG. 51). With the Z key inserted into the core  126 , the gaps/breaks between the drive tumbler  128  and tumblers  114  are aligned with shear line  146  (FIG. 48). Rotating the Z key to the third position, the core  126  and sleeve  124  (cylinder  122 ) rotate together (FIGS. 47, 53). The rotation of the Z key to the third position causes the locking pins  148  to shift (opposite direction) thus aligning them so that the gaps/breaks between them are aligned with the shear line  140  (FIG. 47) and inactivating the blocking function. Rotating the Z key from the third position back to the first position keeps the blocking function inactive and allows the removal of the Z key and the insertion of the A key(s) into the core  126  (FIG. 46). With the A key(s) inserted, the gaps/breaks between the drive tumblers  128  and the tumblers  114  are aligned with the shear line  140  (FIG. 46). The A key(s) is now allowed to rotate the core  126  (FIG. 54).  
         [0096]    FIGS.  55 - 57  illustrate a variation on the alternate embodiment of FIGS.  42 - 54  which includes placement of a second detent pin  150 , a second detent pin spring  152 , a second detent pin retainer  154  and a second detent pin sleeve  156  acting on the new medium locking pin  158  housed in a new sleeve  159 . This new medium locking pin  158  is designed to accept the second detent pin  150  (FIGS. 55, 56), thereby ensuring that the new medium locking pin  158  remains extended through the shear line  140  between the core  126  and the new sleeve  159  thus generating greater strength when the blocking function is activated (FIG. 57).  
         [0097]    Having now fully set forth the preferred embodiments and certain modifications of the concept underlying the present invention, various other embodiments as well as certain variations and modifications of the embodiments herein shown and described will obviously occur to those skilled in the art upon becoming familiar with said underlying concept. It is to be understood, therefore, that the invention may be practiced otherwise than as specifically set forth in the appended claims.