Abstract:
A hierarchical lock system includes a first cylinder lock having a cylindrical plug, rotatable, reciprocating tumbler pins, a slider disposed within the plug and a side bar that cooperates with the cylinder plug, the slider, and the tumbler pins to control rotation of the lock. A second cylindrical lock includes a cylindrical plug, reciprocating tumbler pins, a slider, and a side bar that cooperates with the cylindrical plug and the slider. A first key is configured to open both the first and second locks by elevating and rotating the tumbler pins, and moving the slider to an unlocked position with respect to the side bar. A second key is able to open only the second cylindrical locks by elevating but not rotating the tumbler pins and by moving the slider to an unlocked position with respect to the side bar.

Description:
CROSS REFERENCE OF RELATED APPLICATION 
   This application claims priority from U.S. Provisional Application No. 60/894,792 filed Mar. 14, 2007, the disclosure of which is hereby incorporated by reference. 

   FIELD OF THE INVENTION 
   This invention relates to cylinder locks having tumbler pins which, when operated with the proper keys, are positioned to permit operation of the lock, and particularly to security locks arranged in systems where different cylinders offer varying degrees of physical security, and can be operated by keys in a hierarchical arrangement. 
   BACKGROUND OF INVENTION 
   Customers of security lock systems have recognized the importance of having high security mechanisms on vulnerable doors. The protection offered by these cylinders more than justifies their cost. However the expense to equip all the doors in a facility with modern high security cylinders often offsets the potential benefit of having high security cylinders on nonessential doors. Many customers choose to install and maintain two different master key systems, one for the high security doors and one for the common, less critical doors, thus having more keys to manage and carry for access. 
   This has lead to the development of so-called hierarchical lock systems. A hierarchical lock system includes one or more high security cylinders, typically installed on critical, high-risk doors, and associated lower security cylinders installed on less critical doors. The lower security cylinders are “associated” with the high security cylinders in the sense that a high-security master key, capable of operating the high security cylinder, is also capable of operating each of the associated lower security cylinders. Lower security keys for operating the associated lower security cylinders are not, however, capable of operating the high security cylinders with which the cylinders are associated. Each lower security cylinder may also have one or more associated cylinders of still lower security. And any key capable of operating cylinders at one security level is also capable of operating associated cylinders at lower levels, but the keys constructed to operate only lower security cylinders cannot operate higher security cylinders with which the lower security cylinders are associated. 
   In the context of this description, a standard security cylinder is a cylinder having fewer security features than a high security cylinder. The standard security cylinder is not necessarily the cylinder with the fewest security features within any particular hierarchical scheme. 
   Several lock manufacturers currently make cylinders that can be arranged into systems with different levels of physical security. As the industry produces new and higher security products it is necessary to develop standard security lock cylinders (i.e., non-high security cylinders) that will interface into systems with the newer high security cylinders and be operated by the high security keys. Notwithstanding improvements in the well worked lock art, there remains a need for lock cylinders which offer different levels of protection against criminal attack or other unauthorized entry and which can be arranged into one hierarchical keying schedule. Such lock mechanisms should also resist contemporary lock picking techniques, and it is desirable that the dimensions of the lock not exceed conventional cylinder size. It is equally important that the components and the lock assembly can be economically mass produced. 
   PRIOR ART 
   In U.S. Pat. No. 4,103,526, Serko, Jr teaches a cylinder that has interconnected rotating pins. Insertion of a proper angularly bitted key into the key plug causes the tumbler assemblies to elevate and rotate to predetermined releasing positions wherein a split line of each tumbler assembly is aligned with a shear line between the plug and the shell and each pin tumbler is free to separate from its associated driver to permit rotation of the key plug to an unlocked position. Emhart Industries, Inc. (Berlin, Conn.) introduced this cylinder into the lock market as the high security cylinder in a two-level hierarchical keying system. The corresponding standard security cylinder is a common pin cylinder with conically-shaped pin tips and keys having conventional, straight bittings. The standard security keys will not operate the high security cylinder which requires that the pin tumblers be elevated and rotated, but, the high security key will position the common pins in the standard security cylinder. There are no additional security enhancements in the standard security cylinder. 
   In German patent DE 2828343, Perkut shows a pin tumbler cylinder with two axial sliding pins located beside the key way. The pins are positioned by ribs extending from the side of the key. This cylinder has been manufactured by Gebr. Grundmann Gesellschaft m.b.H., (Herzogengerg, Austria) and sold as the high security cylinder in a hierarchical keying system. The standard security cylinder is manufactured without the axially sliding pins, and the standard security key for the standard security cylinder does not have the side ribs to position the sliding pins in the high security cylinder. The high security key will operate both the high security cylinder and the standard security cylinder, because the standard security cylinder has a key way that is designed to accept the wider key of the high security design. 
   In U.S. Pat. Nos. 4,356,713, 4,393,673 and others, Widen introduced a high security sidebar locking cylinder that could be used in a hierarchical keying system. In one product, the standard security cylinder uses only common pin tumblers, and does not utilize the side pins that are in the high security cylinder. The standard security key will only operate in the standard security cylinder. The high security key will operate both levels of cylinders. 
   In U.S. Pat. No. 5,419,168, the disclosure of which is incorporated herein by reference, Field discloses a hierarchical system of locks wherein each key is provided with at least one unique bitting surface that engages a complementarily shaped tumbler pin tip to cause the tumbler pin to rotate and be positioned at a predetermined location. In one system, one high security key is provided with bittings to rotate the tumbler pins in a lock that is able to determine the rotational position of the tumbler pins. The high security key may also operate a standard security cylinder—which does not determine the rotational position of the tumbler pins—by positioning a tumbler pin at its proper elevation in the cylinder. The standard security key, which has at least one different bitting from the high security key, will operate the standard security cylinder (in which the tumblers do not have to be rotated). The standard security key will not, however, operate the high security cylinder, because the bitting does not properly rotate the tumbler pins to their unlocking locations. 
   Cylinders which read the rotational positioning of the tumbler pins require that the tumbler pins be individually rotated to a predetermined position to permit rotation of the plug or barrel. Such cylinders can be operated only by a key which is bitted so as to rotate the tumbler to the predetermined position. On the other hand, lock cylinders which do not have a mechanism which reads or differentiates between rotational positions of the pins can be operated by any key which is bitted so as to position the pins at their proper elevation and permit rotation of the plug or barrel, regardless of the rotational position to which the key moves the pins. 
   In U.S. Pat. Nos. 6,477,875 and 6,945,082, the disclosures of which are incorporated herein by reference, Field et al. teach lock cylinders that require the precise elevational and rotational positioning of rotating pins and the proper axial positioning of a reciprocating, sliding sidebar blocking mechanism (referred to as a slider) before their plugs will turn. The unique key that operates the cylinder has a portion of a rib configured to cooperate with the slider in the cylinder. The slider provides hierarchical key system differentiation by allowing master keying possibilities on the slider contact areas. It provides an additional bitting member and enhanced security against picking and manipulation. Some examples of slider contact surfaces on the slider are illustrated in U.S. Pat. No. 6,945,082, FIG. 8 at reference numbers 721,713. Also, some examples of slider engaging projections on keys are illustrated in U.S. Pat. No. 6,945,082, FIG. 14a at reference numbers 4007, 4008. 
   The slider and side key bitting also reduces the need for manufacturing as many cylinders of differing key ways to produce a large master keyed system, as the slider mechanism expands the master keying capability of the cylinders without relying on different key sections to reject improperly configured keys. 
   SUMMARY OF THE INVENTION 
   Against this background, the primary object of this invention is to provide an improved locking cylinder of the general kind indicated in the opening paragraph, that will fit into a hierarchical arrangement of cylinders providing a cost effective solution to supplement high security cylinders and keys of the kinds described in U.S. Pat. Nos. 6,477,875 and 6,945,082. 
   Aspects of the invention are embodied in a lock which comprises a cylindrical plug having an axis and an axially-extending keyway adapted to receive a conforming key. The lock also includes tumbler pin assemblies disposed within tumbler pin holes that are formed in the cylindrical plug and which are adapted to control rotation of the cylindrical plug with respect to a shell. Each tumbler pin assembly is reciprocally moveable within an associated tumbler pin hole, and engagement of the tumbler pin assemblies by the biting of a properly configured key inserted into the keyway will position the tumbler pin assemblies within their associated tumbler pin holes so as to permit the cylindrical plug to rotate with respect to the shell. A sidebar is coupled with the cylindrical plug and has an outer end that is engageable with a sidebar groove formed in the wall of a bore formed in the shell. When engaged with the sidebar groove, the sidebar blocks rotation of the cylindrical plug with respect to the shell. A slider is disposed with respect to the cylindrical plug and is adapted to move axially relative to the cylindrical plug, when engaged by a properly configured key inserted into the keyway, from a first position in which the slider interferes with the sidebar to block the sidebar from moving radially inwardly toward the axis of the cylindrical plug to a second position in which the slider does not interfere with the sidebar. With the slider moved to the second position, the sidebar is permitted to move radially toward the axis of the cylindrical plug so that the sidebar disengages from the sidebar groove and permits the cylindrical plug to rotate within the bore formed in the shell. The lock is unlocked when the tumbler pin assemblies are positioned so as to permit the cylinder plug to rotate and the slider is moved to its second position so as to permit the sidebar to move radially inwardly and disengage from the sidebar groove. 
   Other aspects of the invention are embodied in a hierarchical lock system which includes a first cylinder lock having a rotatable cylinder with an axis and a keyway, a movable sidebar for controlling rotation of the cylinder, rotatable reciprocating tumblers for controlling rotation of the cylinder and movement of the sidebar, and a slider adapted to be engaged by a key inserted into the keyway for controlling movement of the sidebar. The system further includes a second cylinder lock having a rotatable cylinder with an axis and a keyway, a movable sidebar for controlling rotation of the cylinder, reciprocating tumblers for controlling rotation of the cylinder, and a slider adapted to be engaged by a key inserted into the keyway for controlling movement of the sidebar. The system also includes a dual level key adapted to open both the first and second cylinder locks and a single level key adapted to open the second cylinder lock but not the first cylinder lock. 
   Other aspects of the invention are embodied in a set of keys which includes a first key comprising a key blade adapted to fit into the keyways of the first and second cylinder locks described above and constructed and arranged to (1) elevate the tumblers of the first cylinder lock to positions which allow the cylinder of the first cylinder lock to rotate, (2) rotate the tumblers of the first cylinder lock to orientations which unblock the sidebar of the first cylinder lock, and (3) elevate the tumblers of the second cylinder lock to positions which allow the cylinder of the second cylinder lock to rotate. The blade of the first key is further constructed and arranged to engage the sliders of the first and second cylinder locks and move each slider parallel to the axis of the cylinder to unblock the sidebar of the first and second cylinder locks. The set of keys also includes a second key which comprises a key blade adapted to fit into the keyways of the first and second cylinder locks and constructed and arranged to elevate the tumblers of the second cylinder lock to positions which allow the cylinder of the second cylinder lock to rotate. The blade is further constructed and arranged to engage the slider of the second cylinder lock and move the slider parallel to the axis of the cylinder to unblock the sidebar of the second cylinder lock. The second key is not adapted to rotate the tumblers of the first cylinder lock and is therefore unable to open the first cylinder lock. 
   Other objects, features, and characteristics of the present invention, including the methods of operation and the function and interrelation of the elements of structure, will become more apparent upon consideration of the following description and the appended claims, with reference to the accompanying drawings, all of which form a part of this disclosure, wherein like reference numerals designate corresponding parts in the various figures. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a left-hand exploded perspective view of a standard security cylinder of the present invention; 
       FIG. 2  is a right-hand exploded perspective view of the cylinder shown in  FIG. 1 ; 
       FIG. 3  is a front view of the cylinder shown in  FIG. 1 ; 
       FIG. 4  is a right-hand exploded perspective view of a prior art high security cylinder; and 
       FIG. 5  is a front view of the cylinder shown in  FIG. 4 . 
       FIG. 6A  is a perspective view of a key adapted to elevate tumbler pins and to engage and move a slider. 
       FIG. 6B  is a perspective view of a key adapted to elevate and rotate tumbler pins and to engage and move a slider. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIGS. 1 ,  2  and  3  show the new and novel cylinder of this invention. This new cylinder can be used as a standard security cylinder and can be operated by keys of the type disclosed in U.S. Pat. No. 6,945,082. As described in more detail below, the cylinder of  FIGS. 1-3  can be operated without rotating the pin tumblers into proper positions, but includes a sidebar and blocking slider arrangement which controls operation of the cylinder. Without the mechanism to read precisely rotated pins of the prior art, the cylinder of the present invention has a reduced cost to manufacture, while the sidebar/slider mechanism offers additional security over prior art standard security cylinder designs. 
     FIGS. 4 and 5  are prior art high security cylinders of the type manufactured by Medeco Security Locks, Inc. of Salem, Va. and which are disclosed in U.S. Pat. No. 6,477,875. As with the cylinder shown in  FIGS. 1 ,  2 , and  3 , the cylinder of  FIGS. 4 and 5  can also be operated by keys of the kinds disclosed in U.S. Pat. No. 6,945,082. This allows for two types of cylinders, one with standard security and one with high security to be arranged in a hierarchical system with keys that operate both levels. 
     FIG. 1  is an exploded, perspective view of the standard security cylinder of the present invention showing the left hand side of the components.  FIG. 2  shows the same components from the right hand side. They illustrate one configuration of a cylinder body or shell  10 . The shell  10  has an axial bore  11  in which a cylindrical plug  20  fits and can rotate. The plug  20  is held in place by a retainer  60 . In the plug  20  and the shell  10  are tumbler pin holes  23  and  13 , respectively, in which pin sets, or tumbler pin assemblies, of various bottom pins  50 , top pins  58 , and springs  56  are positioned. Arrangements of spring loaded pins provide master keying capability and are well known in the lock art. The pins  50  have conical tips  52 , and can be properly positioned to permit rotation of the plug  20  within the shell  10  merely by being elevated to the correct position by a key having the proper bitting pattern. Rotation of the pins  50  is not necessary, and the biting of the key need not be angularly chiseled or skewed. 
   A sidebar  30  is positioned in a cavity  21  formed in the side of the plug  20 . The sidebar  30  has a beveled projection  31  that extends into an axial sidebar groove  12  formed in the sidewall of the axial bore  11  in the shell  10 . The sidebar  30  is urged radially outwardly from the rotational axis of the plug  20 , for example, by springs  38 , so that the beveled projection  31  is urged into engagement with the sidebar groove  12 . The plug  20  cannot be rotated to unlock the lock until the sidebar  30  is moved radially toward the rotational axis of the plug  20 , and the beveled projection  31  is disengaged from the sidebar groove  12 . 
   A slider  40  is positioned adjacent the sidebar  30  and has at least one tab  41  that is engaged by a side  34  of the sidebar  30  to prevent the sidebar  30  from moving radially out of engagement from the sidebar groove  12 . The slider  40  is biased axially, for example, by a spring  48 , toward the front end of the plug  20 . A proper key (described below) inserted into a keyway  36  has a projection that engages a contact surface  42  on the slider  40  to move the slider  40  axially so as to align slider opening(s)  32  formed in the side  34  of the sidebar with the tab(s)  41  of the slider  40 . 
   As the plug  20  is turned under control of the key, the beveled projection  31  moves in the sidebar groove  12 , and this action forces the sidebar  30  to move radially into the plug  20 . The radial movement of the sidebar  30  with respect to the slider  40  and the plug  20  is enabled by the alignment of the slider opening(s)  32  with the tab(s)  41 . 
   As explained in U.S. Pat. Nos. 6,477,875 and 6,945,082, the slider contact areas on the key engage the contact surface  42  on the slider  40  and position the slider to an exact axial location. When the slider  40  is in this operating position, the slider tab  41  is aligned with the slider opening  32 , and the sidebar  30  can move far enough to allow rotation of the plug  20 . Thus, the slider  40  controls the release of the sidebar  30 . 
     FIG. 3  is a front view of the standard security cylinder, illustrating the plug  20  disposed within the shell  10  and the conical tip  52  of a bottom pin  50  and the contact surface  42  of the slider  40  extending into the keyway  36 . 
     FIG. 4  is an exploded view of a prior art high security cylinder which may be used in a hierarchical lock system in conjunction with the standard security cylinder of  FIGS. 1-3 . Rotating or twisting tumbler locks with side bar control of the tumblers and keys for operating such locks are well known in the prior art and have been manufactured and sold by Medeco Security Locks, Inc. of Salem, Va. for over twenty years. Examples of such cylinders can be found in the following patents assigned to Medeco Security Locks, Inc.: U.S. Pat. No. 3,499,302 Spain et al (1970) U.S. Pat. No. 3,722,240 Spain et al (1973), U.S. Pat. No. 4,635,455 Oliver (1987), U.S. Pat. No. 5,289,709 Field (1994), U.S. Pat. No. 5,419,168 Field (1995), U.S. Pat. No. 5,570,601 Field (1996), U.S. Pat. No. 5,615,565 Field (1997), and U.S. Pat. No. 6,023,954 Field (2000). With the addition of a slider, controlling the sidebar as shown in U.S. Pat. Nos. 6,477,875 and 6,945,082, the security of these cylinders is further enhanced. 
     FIGS. 4 and 5  illustrate one configuration of a cylinder body or shell  110 . The shell has an axial bore  111  in which the plug  120  fits and can rotate. The plug  120  is held in place by a retainer  160 . A sidebar  130  is positioned in a cavity  121  in the side of the plug  120 . The sidebar has a beveled projection  131  that extends into a sidebar groove (not shown) formed in the side wall of the axial bore  111  in the shell  110 . Sidebar legs  133  project radially inwardly from the sidebar  130 . A slider  140  is positioned adjacent the sidebar  130 . Additionally the high security level cylinder has drill resistant inserts  170  in the cylinder to provide attack protection. 
   In the plug  120  and the shell  110  are tumbler pin holes  123  and  113 , respectively, in which tumbler pin assemblies of various chisel pointed bottom pins  150 , top pins  158 , and springs  156  are positioned. Arrangements of spring loaded pins are well known in the lock arts, and they can provide master keying capability. The tips  152  of the rotating pins  150  are chisel pointed, and when a correctly bitted key is inserted into the plug, the springs push the pins into the angled cuts on the keys, as explained in the Medeco patents listed above. This action causes the pins to elevate and rotate to an exact location. In the side of the pins is at least one sidebar leg slot  153  designed to accept a leg  133  of a sidebar  130 . 
   As a plug is turned under control of a key (not shown), the beveled projection  131  moves in the sidebar slot, and this action forces the sidebar  130  into the plug  120  against a biasing force, such as springs  138 . Proper rotation of the pins  150  aligns the sidebar leg slot  153  on each pin  150  with one of the sidebar legs  133  and allows the sidebar leg  133  to fit into the pin. In one side of the sidebar there is at least one slider opening  132 , and on the slider  140  there is at least one slider tab  141  that extends upwards behind the sidebar  130 . The slider is spring loaded and is positioned axially in the plug by the key as it is inserted into the cylinder. As explained in U.S. Pat. Nos. 6,477,875 and 6,945,082, the slider contact areas on the key engage the contact surface  142  on the slider  140  and position the slider  140  to an exact axial location with respect to the sidebar  130 . When the slider is in this operating position, the slider tab  141  is aligned with the slider opening  132 , and the sidebar  130  can move far enough to allow rotation of the plug  120 . Both the alignment of the pins and the slider control the release of the sidebar so as to permit rotation of the plug  120 . 
     FIG. 5  is a front view of the prior art high security level cylinder, illustrating the plug  120  disposed within the shell  110  and the chiseled tip  152  of a bottom pin  150  and the contact surface  142  of the slider  40  extending into the keyway  136 . 
   Keys for use in the hierarchical lock system of the present invention are shown in  FIGS. 6A and 6B .  FIG. 6A  shows a key  200  with a bow  202  and a key stop  204  with a blade  206  extending from the key stop  204 . Blade  206  includes bitting  210  and a profile, for example, defined by a longitudinal rib  208 , which conforms to the keyway of a lock. Key  200  includes standard straight bitting  210 , which will elevate the tumblers but will not rotate the tumblers. Key  200  further includes a longitudinally extending cutout  212  having a contact surface  214  defined at an end thereof. The key  200  shown in  FIG. 6A  will operate the locks of the type shown in the  FIGS. 1 ,  2 , and  3 . That is, the bitting  210  will elevate the tumbler assemblies, and the contact surface  214  will contact the projection  42  of the slider  40  and move the slider to a non-interfering position with respect to the sidebar  30 . Key  200  will not operate the locks shown in  FIGS. 4 and 5 , as those locks require that the tumbler pins be elevated and rotated, which key  200  is incapable of doing. Key  220  shown in  FIG. 6B  also includes a bow  222  and a key stop  224  from which the key blade  226  extends. The key blade includes a profile, for example, defined by longitudinal rib  228 , and bitting  230 . A longitudinal cutout  232  extends along a portion of the blade  226  and ends in a contact surface  234 . The bitting  230  of the blade  220  is chiseled, so that, when the biting engages a complementarily chiseled tumbler pin, the biting will elevate and rotate the pin. Accordingly, the key  220  shown in  FIG. 6B  will operate the locks shown in  FIGS. 4 and 5 . In addition, key  220  will also operate the locks shown in  FIGS. 1 ,  2 , and  3 . Thus, in a hierarchical lock system, key  220  is a master key, while the key  200  is a subordinate key. 
   Thus, the standard security cylinder shown in  FIGS. 1 ,  2 , and  3  can be operated by a key having the correct bitting to properly elevate the pin tumblers  50  and the correct slider-engaging rib to axially position the slider  40  with the slider tab(s)  41  aligned with the slider opening(s)  32  formed on the sidebar  30 . Both high security keys, having chiseled, angular or skewed bittings, and standard security keys, having non-angled bittings, can operate the standard security cylinder. On the other hand, the high security cylinder shown in  FIGS. 4 and 5  can only be operated by a key having the correct bitting to properly elevate and rotate the pin tumblers  150  and the correct slider-engaging rib to axially position the slider  140  with the slider tab(s)  141  aligned with the slider opening(s)  132 . Thus, only the high security key, with chiseled, angular bitting, will operate the high security lock of  FIGS. 4 and 5 . 
   Thus, the standard security cylinder of the present invention provides a security enhancement over prior art standard security cylinders which require only the proper elevational positioning of the pin tumblers to permit operation of the cylinder. The standard security cylinder of the present invention also requires the proper positioning of the slider with respect to the sidebar. This security enhancement of the standard security cylinder of the present invention is accomplished without the expense and complexity of prior art high security cylinders which require elevational positioning and rotation of the pin tumblers in addition to the proper positioning of the slider. 
   Accordingly, the standard security cylinder of  FIGS. 1-3  and the high security cylinder of  FIGS. 4 and 5  could form lower and upper levels, respectively, of a two-level hierarchical lock system. Alternatively, the standard security cylinder of  FIGS. 1-3  and the high security cylinder of  FIGS. 4 and 5  could form mid and upper levels, respectively, of a three-level hierarchical lock system, with a prior art standard security cylinder operable upon the proper elevation of the pin tumblers forming the lower level of the system. 
   While the present invention has been described and shown in considerable detail with disclosure to certain preferred embodiments, those skilled in the art will readily appreciate other embodiments of the present invention. Accordingly, the present invention is deemed to include all modifications and variations encompassed within the spirit and scope of the following appended claims.