Patent Publication Number: US-8122746-B2

Title: Electromechanical cylinder plug

Description:
CLAIM FOR PRIORITY AND CROSS-REFERENCE TO RELATED APPLICATIONS  
     This application is a divisional of Applicant&#39;s Ser. No. 08/720,070 filed in the U.S. Patent &amp; Trademark Office on 27 Sep. 1996, and assigned to the assignee of the present invention. This application also makes reference to, incorporated the same herein, and claims all benefits accruing under 35 U.S.C. §§119 and 120 from provisional applications entitled Electromechanical Cylinder Plug earlier filed in the United States Patent &amp; Trademark Office on the 29 Sep. 1995 and duly assigned Ser. No. 60/004,594, and filed in the United States Patent &amp; Trademark Office on the 12 Feb. 1996 and duly assigned Ser. No. 60/011,764. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to access security systems generally, and more particularly, to electromechanical locks and to the plugs and cylinders of electromechanical locks. 
     BACKGROUND ART 
     In an effort to both control and monitor access, state-of-the-art contemporary access security systems have begun to electrically couple the hardware of individual locks to a central, or host, computer. This enables the systems at a minimum, to monitor the operation of each lock and more commonly, to additionally control access to the space guarded by each lock by the expedient of controlling, or at least regulating operation of individual locks. Although some systems rely simply either wholly, or partially, upon recognition of a code borne by a pass, or credential, that contains a memory (e.g., a magnetic strip or embedded memory chip) bearing a code unique to the pass, more elaborate systems such as the ELECTRONIC SECURITY SYSTEM of R. G. Hyatt, Jr., et al. disclosed in U.S. Pat. No. 5,140,317 issued on 18 Aug. 1992, use both an electronic lock mechanism and an electronic key, both of which are provided with a microprocessor and a memory storing an identification code. More recent efforts such as the DUAL CONTROL MODE LOCK of T. J. DiVito, et al., U.S. Pat. No. 5,423,198 issued on 13 Jun. 1995, endeavors to further enhance access security by first having the blade of a key bearing the correct profile and bitting transmit an enable signal upon insertion into the keyway of a particular rekeyable locking mechanism, and then having a second coded signal electromagnetically displace one or more pin tumbler stacks to enable rotation of the plug relative to the cylinder. 
     It has been my observation that these access security systems tend to require complete replacement of each previously installed locking mechanism. I have found that this is not always feasible because some locks have a cylinder formed as an integral part of the secured item (e.g. a hospital drug cart), while other items and areas lack sufficient space to accommodate replacement of an existing mechanical lock with the larger volume of a contemporary electromechanical lock. Moreover, contemporary electromechanical lock systems typically require that each lock be electrically wired into a network with either a source of power or a data or control bus. While this is possible with many architectural applications and with secured items such as a coin box of a pay telephone, in other situations I have found that either the remote location of the lock, the difficulty in stringing the necessary wiring, or customs in the particular industry concerning placement of a lock on the secured item, or area, make the installation of an electromechanical lock that is wired into a network impractical. 
     I have also noticed that both the expense of the complete replacement of each locking mechanism and the expense of the replacement electromechanical locking system have limited the market for such systems to users where either enhanced security is paramount (e.g., hospital drug cabinets) or excess system costs are not a disadvantage because the user (e.g. a regulated utility such as a telephone company that installs electromechanical locks on the coin boxes of its pay telephones) is able to claim an annual return based upon the cost of savings generated by the system. I have discovered that although both classes of users would be able to attain the same level of security from less elaborate systems, the willingness of such users to readily bear these costs as well as the ages old illusion of security concomitant with expense, has hidden the possibility of improving upon current access security systems. 
     Moreover, I have found that despite their innate complexity, many contemporary electromechanical lock systems are able to provide only a single level of access security; thus the cost of equipping each user to use a particular lock remains the same—each user must have the same expensive battery powered microprocessor controlled key, despite the fact that different users of that lock may have different levels of access via that lock. Loss or damage of the microprocessor controlled key can not, in my observation, be minimized by the owner of the lock. Furthermore, electromechanical locking systems tend, because of their excessively elaborate designs, to be unique to their manufacturers. Accordingly, users become captive to their initially selected manufacturer. Consequently, other potential classes of users subject to considerations of costs for replacement of existing locks, costs of the replacement systems as well as costs of operation of the replacement and costs of periodic repair and maintenance, have been denied the benefits of less expensive electromechanical locking systems able to provide the same level of access security, despite the fact that security is also a paramount concern of such users (e.g. a prison or other governmentally funded institution). 
     SUMMARY OF THE INVENTION 
     It is therefore, one object to the present invention to provide a more sophisticated electromechanical locking mechanism. 
     It is another object to provide a plug suitable to readily convert an existing locking mechanism into an electromechanical locking mechanism. 
     It is still another object to provide a replacement plug able to incorporate an locking mechanism into an electromechanical locking system. 
     It is yet another object to provide an electromechanical locking system able to accommodate a hierarchy of access security requirements. 
     It is still yet another object to provide lock components enabling retrofitting of an existing locking mechanism with an electromechanical locking mechanism, without requiring replacement of all of the components of the existing locking mechanism. 
     It is a further object to provide lock components enabling conversion of an existing locking mechanism into an electromechanical locking system, by replacing less than all of the components of the existing locking mechanism. 
     It is a still further object to provide an electromechanical plug that, with a minor alteration of a lock&#39;s cylinder, enables the lock to be incorporated into an electromechanical locking system. 
     It is a yet further object to provide an electromechanical lock able to be set to a plurality of operationally locked, unlocked, and partially bypassed conditions. 
     It is a still yet further object to provide an electromechanical plug that enables each lock to be individually set, either locally or remotely, to grant access to a secured item or area in response to any one of a plurality of keys providing a plurality of different keys levels of operational access. 
     It is also an object to provide an electromechanical locking mechanism having its electronic circuits and all of its electromechanical actuating elements incorporated wholly into the body of a plug. 
     It is an additional object to provide an electromechanical locking mechanism that is amenable for use both as one lock within an electrical network of electromechanical locks and alone independently of any host electrical power or control network. 
     It is a still additional object to provide a drop-in substitute plug able to convert contemporary cylindrical locks into electromechanical locks able to provide a plurality of different levels of access security. 
     These and other objects may be achieved with a hierarchically adaptable lock using a removable cylindrical plug rotatably held with a lock cylinder of a locking mechanism. The plug has an exposed terminal face base perforated by a keyway and a distinct electrical contact aperture. The plug contains either a mechanical locking mechanism, such as a rekeyable tumbler stack, and an electrical operator, or simply a key retaining mechanism and an electrical operator, wholly within the cylindrical exterior surface of the plug. The opposite base of the plug operationally supports a tailpiece able to rotate a cam and position a bolt of the locking mechanism. After insertion of a blade of a properly bitted and profiled key, electrical power, or alternatively electrical power and a data signal superimposed upon the electrical power, may be transmitted from electrical circuits of the key to the electrical operator within the plug. Activation of the electrical operator within the plug, in conduction with correct displacement of the mechanical locking mechanism, or in the embodiments constructed without a mechanical locking mechanism, simply activation of the electrical operator, enables rotation of the plug within the cylinder as torque is manually applied to the blade of the key. An electronic memory, or an electronic memory and an electronic logic circuit wholly contained within the plug, may be electrically interposed between the electrical operator and the electrical contacts receiving power, or power and data signals, from the key. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more complete appreciation of this invention, and many of the attendant advantages thereof, will be readily apparent as the same becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings in which like reference symbols indicate the same or similar components, wherein: 
         FIG. 1  is an exploded perspective view showing the details of a structure able to support several alternative embodiments of a lock constructed according the to principles of the present invention; 
         FIG. 2  is a top detailed view of an electrical operator of a type suitable for use in the embodiments shown in  FIG. 1 ; 
         FIG. 3  is an enlarged cross-sectional detail view showing the structure of a first embodiment of a lock constructed according the to principles of the present invention; 
         FIG. 4  is a top detailed view of one armature of an electrical operator of a type suitable for use in the embodiments shown in  FIG. 1 ; 
         FIGS. 5A and 5B  are two enlarged cross-sectional detailed views showing two different operational positions of the structure of a second embodiment of a lock constructed according to the principles of the present invention; 
         FIG. 5C  is a side cross-sectional view of another embodiment, showing one phase of the operation of the lock; 
         FIG. 5D  is a side cross-sectional view of the embodiment illustrated in  FIG. 5C , showing another phase of the operation of the lock; 
         FIG. 5E  is a side cross-sectional view of one design for a motor suitable for use in the embodiments shown in  FIGS. 5A ,  5 B,  5 C and  5 D; 
         FIG. 5F  is a plan cross-sectional view taken along sectional line VF-VF′ in  FIG. 5E , of one detail of the motor shown in  FIG. 5C ; 
         FIG. 6  is a top detailed view of an armature for another electrical operator of a type suitable for use in the embodiment shown in  FIG. 1 ; 
         FIG. 7  is an enlarged cross-sectional detailed view showing the structure of the embodiment incorporating the armature illustrated in  FIG. 6 ; 
         FIG. 8A  is an exploded perspective view of another alternative embodiment constructed according to the principles of the present invention; 
         FIG. 8B  is an upper plan view of the embodiment illustrated in  FIG. 8A ; 
         FIG. 8C  is a front elevational view of the embodiment illustrated in  FIG. 8A ; 
         FIG. 8D  is a side elevational view of the embodiment illustrated in  FIG. 8A ; 
         FIG. 8E  is a rear elevational view of the embodiment illustrated in  FIG. 8A ; 
         FIG. 8F  is a cross-sectional view of an electrical operator of a type suitable for use in the embodiment illustrated in  FIG. 8A ; 
         FIG. 8G  is a cross-sectional view showing the assembly of the lock illustrated in  FIG. 8A ; 
         FIG. 8H  is an exploded perspective view of another alternative embodiment constructed according to the principles of the present invention; 
         FIG. 9  is an upper plan cross-sectional view illustrating some of the details of the embodiments of  FIG. 1 ; 
         FIG. 10  is a front elevational view illustrating some of the details of the embodiments of  FIG. 1 ; 
         FIG. 11  is a side cross-sectional elevational view illustrating some of the details of the embodiments of  FIG. 1 ; 
         FIG. 12  is a rear elevational view illustrating some of the details of the embodiments of  FIG. 1 ; 
         FIG. 13  is an enlarged cross-sectional detailed view showing the structure of an alternative embodiment constructed according to the principles of the present invention; 
         FIG. 14  is an oblique perspective view of an assembled alternative embodiment constructed according to the principles of the present invention; 
         FIG. 15  is a cross-sectional detailed view showing the structure of an alternative embodiment constructed according to the principles of the present invention; 
         FIG. 16  is an oblique view showing details of a case for a logic circuit that may be incorporated into several of the embodiments of the present invention; 
         FIG. 17  is an oblique view showing details of an alternative embodiment of a case for a logic circuit that may be incorporated into several of the embodiments of the present invention; 
         FIG. 18  is a block diagram illustrating circuits for both a key and a lock, constructed according to the principles of the present invention; 
         FIG. 19  is a diagrammatic view illustrating one configuration of a hierarchical lock cylinder system practiced according to the principles of the present invention; 
         FIG. 20  is a diagrammatic view illustrating a second configuration of a hierarchical lock cylinder system practiced according to the principles of the present invention; 
         FIG. 21  is a diagrammatic view illustrating a third configuration of a hierarchical lock cylinder system practiced according to the principles of the present invention; and 
         FIG. 22  is a diagrammatic view illustrating one configuration of a hierarchical lock cylinder system practiced according to the principles of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     Turning now to the drawings,  FIG. 1  provides an exploded perspective view of a cylindrical camlock  100  of the type in general use for securing access to cabinet doors, drawers and coin boxes. The principles illustrated by camlock  100  are however, readily suitable for other types of locks. As shown in the various views of  FIGS. 1 through 18 , a camlock is assembled with an elongate, cylindrical plug  101  inserted inside the cylindrical cavity  102   d  of cylinder shell, or body,  102 . Typically, lock  100  is constructed with end plate  68  at the terminal end of cylinder  102 , recessed to receive face plate  72  of plug  101  so that the exposed surface of plug  101  lies flush with the face of plate  72 . Absent such key retaining components (i.e., those components of the plug that  3  retain the shank of a key (e.g., such as bitted key  200 ) within the keyway while the plug is rotated from its rest position relative to the shell  102 ) of the locking mechanism as cylindrical pins  101   b  and sidebar  101   g , plug  101  should be sized to freely rotate around an axis that is parallel to the longitudinal axis of cavity  102   d . Plug  101  contains an axially elongated keyway passage  101   a  shown in the front, cross-sectional and rear views of  FIGS. 10 ,  11  and  12 , respectively, extending  8  axially through the exposed front plate  72  of cylindrical plug  101 . Keyway passage  101   a  is configured to accommodate reciprocal insertion of the blade of a key  200  that has been correctly profiled to conform to the profile of keyway  101   a . Although not essential to the practice of all embodiments of the principles of this invention, plug  101  may also contain a mechanical locking mechanism such as a set of pin tumblers  101   b  of the type mentioned in U.S. Pat. Nos. 3,722,240 and 3,499,303 to Oliver. Pin tumblers  101   b  are biased by springs  101   e  into the bottom of corresponding pin chambers  82  by corresponding separate springs  101   e  restrained within the body of plug  101  by coverplate  101   f  fitted snugly into an axially extending slot  101   y  adjacent to the exterior circumferential surface of plug  101 . 
     Plug  101  also contains sidebar  101   g  tapered into an acute (frequently blunted), axially extending bearing edge  101   h  partially recessed into a slot  102   a  formed axially along the exterior circumferential surface of cylinder  102 . Sidebar  101   g  is typically biased radially outwardly by one or more springs  101   k  so that the leading axially extending edge  101   h  of sidebar  101   g  protrudes into  101   a  beveled slot  102   a  of a cylinder  102  encasing plug  101  after the complete plug  101  has been installed into cylinder  102 . Pins  101   b  are cut in this particular embodiment with a groove  101   d . When the blade of a mechanical key that has been bitted to correctly displace pins  101   b  radially outwardly from keyway  101   a  within their corresponding chambers  82  is inserted with the cuts of the land of the key precisely matching the coding (axial separation between the upper and lower portions of pins  101   b ) of pins  101   b , then slots  101   d  will align with the legs, or pegs,  101   m  of the sidebar  102   g . When rotational torque is manually applied to the key by the user, the beveled edges of slot  102   a  enables sidebar  101   g  to move radially inwardly and away from groove  102   a  against the bias of springs  101   k  slightly, but enough to allow plug  101  to rotate within cylinder  102 , thus concomitantly rotating tailpiece  101   q  which, in turn, rotates a movable cam  103  or other member engaged by tailpiece  101   q . In other applications, cam  103  may be connected to and, upon rotation of plug  101  and its tailpiece  101   q , draw a bolt and thereby permit access to a secured item or into a secured area. Other embodiments allow a tailpiece  101   q  with a particular shape to drive a clutch, cam or linkage. 
     The user may then rotate the key until plug  101  is aligned with a key extraction point where alignment between chambers  82  and the corresponding tumbler pins  101   b  allow the bias of springs  101   k  to force sidebar  101   g  radially outwardly until beveled edge  101   h  mates with slot  102   a , and thus permits withdrawal of key  200  from keyway  101   a . A cylinder lock of this type may have two or more grooves, or slots  102   a  spaced arcuately apart to provide several arcuately separate points at which a key may be extracted from plug  101 . When pins  101   b  are engaged in the properly manufactured corresponding cuts in the blade of the key and each of pins  101   b  is correspondingly radially displaced outwardly within its chamber, and legs, or pegs,  101   m  of sidebar  101   g  engage corresponding circular grooves  101   d  formed in some, or all, of pins  101   b  as those pins  101   b  are forced radially outward by the bits of the key. The interengagement of pegs  101   m  and grooves  101   d  prevents radial movement of pins  101   b  and the concomitant release of the blade of the key within keyway  101   a ; the blade may only be extracted from keyway  101   a  when beveled edge  101   h  of sidebar  101   g  is correctly aligned with groove  102   a . It should be noted that features of mechanical lock and key mechanisms other than those mentioned in U.S. Pat. Nos. 3,722,240 and 3,499,303 to Oliver may be used in the practice of the instant invention. 
     A release assembly such as a reciprocating solenoid coil  106   b  driving blocking armature  106   a  shown in greater detail in  FIGS. 2 and 3 , or a rotary motor  108   b  driving blocking armature,  08   a  shown in greater detail in  FIGS. 4 and 5A  and  5 F, or the reciprocating solenoid coil  107   b  of blocking armature  107   a  shown in greater detail in  FIGS. 6 and 7 , resides within (typically cylindrical) chamber  80 . The open distal end of chamber  80  is intersected by a circumferential groove  101   l  which may partially, or completely, encircle the exterior circumferential surface of plug Coil  106   b  has a centrally located hole  106   f  for receiving shaft  106   d  while detent  106 A passes either sidewall  106   e  of blocking armature  106   a . Armature  106   a  forms the radially outward distal end of solenoid coil  106   b , and is radially outwardly biased by spring  106 D so as to extend radially upwardly into the path of groove  101   l  and thereby engage detent  106 A. Release assemblies  106 ,  107 , and  108  are electrically connected to an electronic logic and control circuit  104   b  encapsulated within an electrically insulated casing  104  formed to define an outer sector of cylindrical plug  101 . Power, or power, protocol, identification and control data may be transmitted from a key inserted into keyway  101   a  via electrical conductor  104   x , extending between an aperture  101   n  in the faceplate of plug  101  and the electrical conductor (e.g., a local ground return) formed by the electrically conducting parts forming keyway, respectively, and corresponding input ports to circuit  104   b . Electrical leads  104   m ,  104   n , extend between a pair of output ports of circuit  104   b  and either solenoid coil  106   c  of blocking armature  106   a , or solenoid coil  107   c  of blocking armature  107   a , or motor coils  108   c  of rotary stepping motor  108   a.    
     The electrical power or alternatively, electrical power, operational protocol, identification and control data passes through aperture  101   n  via conductor  104   x  when casing  104  is properly positioned within cavity  101   p . Pegs  101   s  enter corresponding receptacles in casing  104  and position casing  104  relative to plug  101 . When casing  104 , and its electronic circuit, are seated within plug cavity  101   p , casing  104  is contained within the larger diameter of plug  101 , so that the combined plug assembly formed by plug  101  and electronic circuit casing  104  are easily and tightly received within the interior of lock cylinder  102 . Blocking armature  106   a ,  107   a  or  108   a , may be rendered ineffective at limiting or preventing rotation of plug  101  within cylinder  102  and thus considered to be mechanically bypassed until the installation of a cooperating member clip  105 E or  106 E, respectively within slot  102   c  with the respective detent  106 A,  107 A disposed within through aperture  102   b . A selected one of cooperating member clips  105 E or  106 E installs circumferentially around cylinder  102  and is seated within a conforming circumferential groove  102   c  when blocking detent  105 A or  106 A is engaged through slot  102   b . When installed properly, blocking detent  105 A or  106 A extends through slot  102   b  and sufficiently into the exposed recess  106   c , or slot  107   c ,  108   c  in the distal end of the corresponding one of armatures  106   a ,  107   a ,  108   a , and as plug  101  rotates within cylinder  102 , blocking detent  105 A,  106 A travels through groove  101  around the circumference of plug  101 . The shafts  106   d ,  107   d  or  108   d  respectively of blocking armatures  106   a ,  107   a  or  108   a  are made of a magnetically attracted material such as iron or steel. When an unidirectional electrical current is applied through the particular winding  106   b ,  107   b ,  108   b , the corresponding shaft  106   d ,  107   d ,  108   d  will either axially reciprocate (i.e., radially through its corresponding chamber  82 ) along axis A or incrementally rotate (e.g., by ninety degrees within its corresponding chamber  82 ) around axis A and thereby alter the positional relation between blocking detent  106 A or  107 A relative to the corresponding blocking armature  106   a ,  107   a  or  108   a.    
     In the embodiment illustrated by  FIGS. 2 and 3 , cooperating member clip  106 E and blocking armature  106   a  are used as a set to form electromechanical release mechanism  106 . When clip  106 E is inserted into groove  101 P with detent  106 A protruding through slot  102   b , compression spring  106 D will hold armature  101   a  radially outwardly from the coaxial void  106   f  formed by coil  106   b , so that cavity  106   c  will surround detent  106 A. Consequently, sidewalls  106   e  will stand between detent  106 A and circumferential groove  102 P, thereby blocking rotation of plug  101  within cylinder  102 . Assuming that mechanical key cuts (i.e., the “bitting” along the shank of a conventional mechanical key  200 ) correspond with the coding of mechanical pins  101   b , insertion of a key (not shown) into keyway  101   a  and manual rotation of the key in any direction is blocked by obstruction of detent  106 A by stopface  106   e ; application of power to coil  106   b  via contact  104   x  and controller  104 , and a responsive reciprocally downward movement of the magnetically attracted blocking armature  106   a  along axis A toward coil  106   b  enables the straight edge  106 F of blocking detent  106 A to clear the upper edge of stopface  106   e  and to pass freely in that direction within groove  101 P. When power is discontinued to coil  106   b , spring  106 D will then return blocking armature  106   a  to its extended position, thereby again blocking rotation of plug  101  in any direction due to obstruction of detent  106 A by sidewall  106   e . If detent  106 A is within groove  101   l  and is not axially aligned with cavity  106   c  when application of electrical power is withdrawn from coil  106   b , continued manual rotation of the key will cause angular edge  107 B of detent  106 A to engage a slight chamber on the upper edge of armature  106   a  at  106   h ; camming action of edge  106 B will force armature  106   a  to axially reciprocate inwardly within its chamber  80  until detent  107 A is again engaged by the return outward reciprocating movement of armature  107   a  under the bias of spring  107 D. When detent  106 A is coaxially aligned with cavity  106   c , springs  101   k  force edge  101   h  of sidebar  101   g  radially reciprocate outwardly from grooves  101   d  and into groove  102   a , thereby enabling manual withdrawal of the key from keyway  101   a.    
     Turning now particularly to  FIGS. 4 ,  5 A,  5 B,  5 C,  5 D,  5 E and  5 F, when cooperating member clip  106 E and blocking armature assembly  106   a  are used as a set to form release mechanism  108 , clip  106 E will rest within cavity  108   c , defined by two mirror image and spaced apart sidewalls  108   e  in blocking armature  108   a  while plug  101  is in the locked position relative to cylinder  102  with edge  101   h  of sidebar  101   g  resting within groove  102   a . Blocking armature  108   a  is coaxially mounted upon the shaft of a stepping motor  108 A. As represented in  FIGS. 5A ,  5 B,  5 C and  5 D, the stepping motor has a single coil  108   b ; the embodiment shown in  FIGS. 5E and 5F  use a pair of coaxial coils  108   b . The entire motor assembly is encased in a can  108   j  that is in turn, fitted into cylindrical hole Preferably, stepping motor  108 A rotates by ninety degrees in response to application of electrical current to coil, or coils  108   b . Referring now to  FIG. 5A , assuming that upon manual insertion of a key within keyway  101   a , mechanical key cuts along the shank of the key correspond to coding of the row of mechanical pins  101   b , rotation of the key in either direction is blocked by engagement of detent  106 A with sidewalls  108   e  of cavity  108   c  in blocking armature  108   a . Turning now to  FIG. 5B , application of power to solenoid coil  108   b  and an accompanying rotation of blocking armature  108   a  around axis A relative to coil  108   b  in response to flow of the current, enables the straight lowermost edge  106 F of blocking detent  106 A to pass through gap  108   h  between opposite sidewalls  108   e  of cavity  108   c  and to pass freely into groove  101 X, thereby enabling rotation of plug  101  within cylinder  102 . When the key is withdrawn from keyway  101   a , blocking armature  108   a  will remain in its current position, thereby blocking rotation of plug  101  in either direction if the current position is as shown in  FIG. 5A  with sidewalls  108   e  interposed between groove  101   l  and detent  106 A. If however, the current position of blocking armature  108   a  is as shown in  FIG. 5B  when the key is withdrawn, detent  106 A will be able to freely rotate through gaps  108   h  and into groove  101   l  when another key with the correct bitting is inserted into keyway  101   a . If tab  106 A and cavity  108   g  are significantly misaligned when power is discontinued, then rotation of the plug  101  to the key extraction point where mechanical key retaining pins  101   b  may disengage from the key blade due to the movement of sidebar  101   g  into groove  102   a , will position small tapered edge  106 B to encounter chamber  108   g . As plug  101  is rotated farther, armature  108   a  is pushed into the void  108   f  coaxially defined by coil  107   b  until tab  106 A is again engaged by the return outward movement of armature  108   a . NMB Corporation currently manufactures a stepping motor, model number 03BJ-H001-F9 of a type that is sufficiently minaturized to serve in this embodiment. This model uses two separately wound coils  108   b . Application of electrical current to the coils incrementally steps the armature  108   a  to align with the energizied ferrous fingers  108   n  mounted upon the casing and the ferrous fingers  108   p  mounted upon the ferrous divider  108   q . An electrical insulator  108   k  is mounted on shaft  108   d  to serve as a divider. Reversal of electrical polarity to the coils will cause a reversal of the direction of rotation of armature  108   a . Preferrably, each application of power to the coils will initiate a ninety degree rotation so that sidewall  108   e  will either block passage of detent  106 A into groove  101   l , or the alignment of slot  108   h  with detent  106 A will accommodate passage of detent  106 A into groove  101  and thus enable rotation of plug  101  within cylinder  102 . 
     Turning briefly now to  FIGS. 6 and 7 , when cooperating member clip  107 E and blocking armature  107   a  are used as a set to form release mechanism  107 , detent  107 A of clip  107 E will engage stopface  107   e  on blocking armature  107   a , if plug  101  is rotated in one direction. Assuming that the mechanical key cuts (i.e., the “bitting” along the shank of a conventional mechanical key) correspond with the mechanical pin coding, rotation in one direction is blocked by stopface  107   e  and requires application of power to coil  107   b  and a responsive reciprocally downward movement of the magnetically attracted blocking armature  107   a  toward coil  107   b  so that the straight edge  107 F of blocking detent  107 A clears the upper edge of stopface  107   e  and passes freely in that direction within groove  101 P. When power is discontinued to coil  107   b , then spring  107 D will return blocking armature  107   a  to its extended position, thereby blocking rotation of plug  101  in one direction due to obstruction of stopface  107   e  by detent  107 A, while plug  101  is free to rotate in the opposite direction through groove  101   e . If plug  101  is rotated in this opposite direction far enough, angular edge  107 B will engage a slight chamber on the upper edge of armature  107   a  at  107   h ; camming action of edge  107 B forces armature  107   a  axially (radially within its chamber  80 ) inwardly until detent  107 A is again engaged by the return outward movement of armature  107   a  under the bias of spring  107 D. 
       FIGS. 8A through 8F  illustrate the structure of two different drop-in modifications of a contemporary lock, one without requiring alteration of cylinder  102 , and the second requiring a single radial hole into cylinder  102 . An elongate, cylindrical plug  101  is axially inserted inside the cylindrical cavity  102   d  of cylinder  102 . End plate  68  is recessed to receive faceplate  72  of plug  101 . Absent such components of the locking mechanism as cylindrical pins  101   b  and sidebar  101   g , plug  101  should be sized to freely rotate around an axis B that is parallel to the longitudinal axis of cavity  102   d . Plug  101  contains an axially elongated keyway passage  101   a  shown in the front, cross-sectional and rear views of  FIGS. 10 ,  11  and  12 , respectively, extending axially through exposed plate  72  of cylindrical plug  101 . Keyway passage  101   a  is configured to accommodate reciprocal insertion of the blade of a key (not shown) that has been correctly profiled to conform to the profile of keyway  101   a . Although not essential to the practice of all embodiments of the principles of this invention, plug  101  may also contain a mechanical locking mechanism such as a set of pin tumblers  101   b . Pin tumblers  101   b  are biased into the bottom of corresponding pin chambers  101   k  by corresponding separate springs  101   e  restrained within the body of plug  101  by coverplate  101   f ′ covering chambers  80 ,  82 , and fitted snugly into an axially extending slot  101   y  adjacent to the exterior circumferential surface of plug  101 . 
     Plug  101  also contains sidebar  101   g  tapered into an acute (frequently blunted), axially extending bearing edge  101   h  partially recessed into a beveled slot  102   a  formed axially along the exterior circumferential surface of cylinder  102 . Sidebar  101   g  is typically biased radially outwardly by one or more springs  101   k  so that the leading axially extending edge  101   h  of sidebar  101   g  protrudes into slot  102   a  of a cylinder  102  encasing plug  101  after the complete plug  101  has been installed into cylinder  102 . Pins  101   b  are cut in this particular embodiment with a groove  101   d , which may be made circular to accommodate rotation of pins  101   b  during insertion of a key. When the blade of a mechanical key that has been bitted to correctly displace pins  101   b  radially outwardly  6  from keyway  101   a  within their corresponding chambers  82  is inserted with the cuts of the land of the key precisely matching the coding (axial separation between the upper and lower portions of pins  101   b ) of pins  101   b , then slots  101   d  will align with the pegs  101   m  of the sidebar  102   g . When  9  rotational torque is manually applied to the key by the user, the beveled edges of slot  102   a  enables sidebar  101   g  to move radially inwardly toward plug  101  and away from groove  102   a  against the bias of springs  101   k  slightly, but enough to allow plug  101  to rotate within cylinder  102 , thus concomitantly rotating tailpiece  101   q  which, in turn, rotates a movable cam  103  or other member engaged by tailpiece  101   q.    
     The user may then rotate the key until plug  101  is aligned with a key extraction point where alignment between chambers  82  and the corresponding tumbler pins  101   b  allow the bias of springs  101   k  to force sidebar  101   g  radially outwardly until beveled edge  101   k  mates with slot  102   a , and thus permits withdrawal of the key from keyway  101   a . Two or more grooves, or slots  102   a  may be formed into the interior  102   d , spaced arcuately apart to provide several arcuately separate points at which a key may be extracted from plug  101 . When pins  101   b  are engaged in the properly manufactured corresponding cuts in the blade of the key and each of pins  101   b  is correspondingly radially displaced outwardly within its chamber  82 , and pins  101   m  of sidebar  101   g  engage corresponding circular grooves  101   d  formed in some, or all, of pins  101   b  as those pins  101   b  are  2  forced radially outward by the bits of the key. The interengagement of pegs  101   m  and grooves  101   d  prevents radial movement of pins  101   b  and the concomitant release of the blade of the key within  4  keyway  10   l  a; the blade may only be extracted from keyway  101   a  when beveled edge  101   h  of sidebar  101   g  is correctly aligned with groove  102   a.    
     A release assembly such as a reciprocating solenoid coil  105   b  driving blocking armature  105   a  resides coaxially within chamber  80 . Coil  105   b  has a centrally located hole  105   f  for receiving shaft  105   d  when electrical current passes through coil  105   b . Armature  105   a  forms the radially  9  outward distal end of solenoid coil  105   b , and is radially outwardly biased by spring  105 D so as to place a circumferential surface  105   k  to engage, and block, a corresponding pin  101   m  of sidebar  101   g . Release assembly  105  is electrically connected to electronic logic and control circuit  104   b  encapsulated within electrically insulated casing  104  formed to define an outer sector of cylindrical plug  101 . Power, or power, protocol, identification and control data may be transmitted from a key inserted into keyway  101   a  via electrical conductor  104   x , extending between an aperture  101   n  in the face plate  72  and the electrical conductor (e.g., a local ground return) formed by the electrically conducting parts forming keyway, respectively, or alternatively via two or more pairs of apertures  101   n  and electrical conductors  104   x , and corresponding input ports to circuit  104   b . Electrical leads  104   m ,  104   n , extend between a pair of output ports of circuit  104   b  and solenoid coil  105   c  of blocking armature  105   a.    
     Solenoid  105   b  enables an existing plug to be retrofitted simply by substituting solenoid  105   a  in chamber  80  for one of tumbler pins  101   b  and a concomitant re-bitting of the corresponding key to omit from the blade of the key any tooth corresponding to the cylinder occupied by solenoid  105   b , with application of electrical power to solenoid coil  105   b  radially forcing armature  105   a  radially outwardly against the compressive force of spring  101   e  in order to align groove  105   n  with peg  101   m . Alternatively, with a different location of groove  105   n , solenoid  105   b  may be wound to draw blocking armature radially downwardly into cylinder  80 , against the compressive force of a spring  105 D (not shown) positioned between blocking armature  101   a  and coil  105   b.    
     In a particular practice, the diameter of one of pin cylinders  80 ,  82  may not be sufficiently wide to accommodate a particular solenoid and will require reboring of the cylinder. The rebored plug can still be retrofitted into an already installed cylinder however, without the necessity of removing cylinder  102 . 
     Turning again to  FIGS. 13 and 17 , an existing plug and cylinder may also be modified with the addition of an electromagnetic release assembly  109  to the exterior of cylinder  102 , and by radially boring one or more aligned apertures  102   w ,  101   w  through cylinder  102  and into plug  101  to accommodate reciprocal passage of either one, or and array of blocking armatures  109   a . Power for solenoid coils  109   b  may be supplied and switched by a source of electrical power external to the lock cylinder plug  102  via two or more electrical leads  109 E and an external contact assembly  109 F which attaches circumferentially around the outside of the cylinder shell  102  and custom multiple spring loaded pin armatures  109   b  passing through the apertures  102   w  bored into the wall of cylinder shell  102  and entering into the corresponding blind apertures  101   w  bored into plug  101  to prevent rotation of plug  101  relative to cylinder shell  102  even after the blade of a correctly bitted key had precisely radially displaced the pin tumblers  101   b . Installation of contact assembly is made by spreading clip wings  109 H apart enough to allow them to pass around cylinder shell  102  to enable contact guide boss  109 J to seat into through aperture  102   w  and enter aperture  101   w , and wing male catch  109 G′ is firmly engages female catch  109 G. The harness  109 E is placed so as not to interfere with cam  103  and plug connector  109 F may be connected to an external power supply and switching device that is local to the site of the lock, or is connected to a power and control bus to multiple locks. 
     Power may alternately supplied along with data through plug face contacts  104   x  which is connected to printed circuit  104   b . Plug face contact  104   x  passes through face plate  72  from the cavity  101   p  to the outside exposed face of the plug via hole  101   n . In this version data and optionally power may be supplied by the user held door key. A logic circuit with a microprocessor, communication, memory and switching means will be contained in casing  104  and its circuit  104   b . When key means is presented and inserted in the lock and contacts on key means are in electrical contact with contacts  104 , a process of authentication and comparison of encoded data occurs. An agreement of data, will result in the logic circuit switching power to coil  109   b . In the event there is not an agreement of data then the lock remains in its normal state. 
     Turning now to  FIG. 18 , power for the coils  105   b ,  106   b ,  107   b  or  108   b  may be supplied and switched by a source of electrical power such a battery  202  carried by a doorkey  200  external to the lock cylinder plug  101  via one or more external contact assemblies  104   x ,  104   y  as are manufactured by a vendor such as Interconnect Devices, Inc. passing through external contact window  101   n , with contact  104   x  attached to printed circuit  104   b . The circuit board  104   b  is housed or encapsulated in circuit housing assembly  104  and is electrically connected to coil windings  105   b ,  106   b ,  107   b  or  108   b.    
     One hierarchy for a cylinder lock system is represented in  FIG. 19 , using a standard, mechanically bitted key  210  in conjunction with electromechanical key  200 . In this configuration, cylinder locks  211 ,  212  and  213  are stand-along locks of the type using release assemblies  105 ,  106 ,  107  or  108 , that can be opened and closed with electromechanical key  200 . Cylinder locks  214 ,  215  are electrically coupled to a host data and power bus and may be opened and closed with either key  200  or with mechanical key  210 , albeit the centrally located controller  220  controls, and overrides where desired, access through locks  214 ,  215  via power and data bus  222 . Cylinder locks  106 ,  107  are stand-alone mechanical locks and may be accessed by either the correct mechanical bitting of electromechanical key  200  or of mechanical key  210 . 
       FIG. 20  illustrates a second hierarchy of a cylinder lock system in which electromechanical key  200  providing its own electrical power is able to mechanically and electrically unlock and lock stand-alone electromechanical locks  211 ,  212 ,  213  of the types using release mechanisms  105 ,  106 ,  107 ,  108 , while a different electromechanical key  209  is able to unlock and lock cylinder locks  214 ,  215  controlled by a central controller  220  via a host power and data bus  222 . 
     With the configuration illustrated in  FIG. 21 , electromechanical key  200  is able to unlock and lock all of cylinders  211 ,  212 ,  213 ,  214 ,  215 ,  216  and  217 , and to set cylinder  213  into a bypassed state to enable mechanical key  209  to unlock and lock cylinder  213 . 
     In the configuration illustrated in  FIG. 22 , stand-alone locks  211 ,  212 ,  213  using a bypassable release mechanism such as  108 , may be set into a bypassed position by key  200  to allow a simple mechanically precisely bitted mechanical key  210  to unlock and lock these cylinders, while either the same key  200  or alternatively host controller  220 , is able to set locks  214 ,  215  into a condition enabling key  210  to unlock and lock those cylinders. Mechanical locks  216 ,  217  may be independently accessed by key  210 . 
     The foregoing details describe an electromechanical locking system using a plug constructed with a first base bearing a keyway providing a first electrical conductor and an orifice spaced-apart from and separated by a mass of the plug from said keyway; a second base separated by an axial length of the plug from said first base, said second base bearing a tailpiece for supporting a cam; an exterior surface extending between and engaging the first base and the second base; a locking mechanism responsive to a key inserted into said keyway to accommodate rotation of the plug relative to a cylinder surrounding the plug when the key while inserted into the keyway engages in a selected relation with the locking mechanism and engaging the cylinder absent the selected relation; a second electrical conductor terminating with an electrical contact exposed to an exterior of the first base through the aperture; an electronic logic circuit coupled to receive electrical power and data signals via the first and second electrical conductors, and generating control signals in dependence upon the electrical power and data signals; and an electrical operator having a distal member travelling in dependence upon the control signals between a first position relative to the exterior surface enabling rotation of the plug in relation to a cylinder surrounding the plug and a second and different position relative to the exterior surface obstructing the rotation of the plug in relation the cylinder. 
     The plug of this system is constructed with the locking mechanism, logic circuit and electrical operator simultaneously experiencing the rotation relative to the cylinder whenever the plug rotates relative to the cylinder. The plug is constructed with the locking mechanism, logic circuit and electrical operator being wholly within the cylinder and travelling with the plug whenever the plug moves relative to the cylinder. The plug is configured with the electrical operator maintaining the distal member within the plug with the distal member extended not beyond the exterior surface while the distal member is in the first position, and maintaining the distal member in engagement with the cylinder while the distal member is in the second position. The electrical operator maintains the distal member within the plug with the distal member extending not beyond the exterior surface while the distal member is in the first position, and moves the distal member radially between the first position inside the exterior surface and the second position radially beyond the exterior surface, in dependence upon the control signals. 
     Alternative construction of these features is possible without departing from the principles of the present invention. For example, the plug used in  FIG. 1  to illustrate the foregoing principles is described as having a tailstock configured to support a cam. In some configurations, the plug may be configured to drive either a locking mechanism or an electrical switch.