Abstract:
A combination mechanical and electronic lock system for use in cuffs and various other locking applications is disclosed. In the preferred embodiment, the lock is configured to receive a matching key that transmits a code that disengages the electronic lock from the mechanical lock so that the mechanical lock can be manually opened by the user. When implemented in a handcuff, for example, the mechanical lock includes a single lock mechanism and a double lock mechanism; and at least one electronic lock configured to selectively unlock at least a portion of the mechanical lock upon receipt of the proper digital code from the cuff key. The power needed to operate the electronic lock, preferably a solenoid or other actuator, is received directly or indirectly from the cuff key so that the cuff need not possess a battery.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
       [0001]    This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/805,127 filed Jun. 19, 2006, which is hereby incorporated by reference herein for all purposes. 
     
     TECHNICAL FIELD 
       [0002]    The invention generally related to a restraint system using electronic locks. In particular, the invention relates to handcuffs or shackles that incorporate a combination of mechanical locks and electronic locks for use with an electronic key. 
       BACKGROUND 
       [0003]    Since the invention of handcuffs in the early twentieth century, defeating its locking mechanism has posed a threat to law enforcement and the public more generally. Escaped prisoners are typically desperate to avoid recapture and may resort to violence in the process of fleeing authority. Cases in which prisoners have freed themselves from standard cuffs are all too common. 
         [0004]    The design of the common cuff lock has changed little in seventy-five years and is well understood by those who seek to defeat it. In addition, the standard cuff key possesses a generic design and can be used to open most any set of handcuffs or leg restraints. Compounding the problem is the ready availability of the handcuff keys. Handcuff keys can be easily and inexpensively purchased at any American gun show, sporting goods store, or through the Internet. 
         [0005]    Criminals have also learned to breach or bypass standard cuff locks even when in prison or jail. Cuff keys may be smuggled into the prison or a facsimile of a key hand crafted using a wide variety of materials on hand including scrap metal, paper clips, hairpins, toothbrushes, wood, and bone, for example. 
         [0006]    There is therefore a need for a restraint system that employs a lock mechanism that is tamper-proof and a key that is both unique and difficult to improvise. 
       SUMMARY 
       [0007]    The invention features a combination mechanical and electronic lock system for use in cuffs and various other lock applications. In the preferred embodiment, the cuff is configured to receive a matching cuff key that transmits a code that disengages the electronic lock from the mechanical lock so that the mechanical lock can be manually opened by the user. The cuff, for example, comprises a mechanical lock including a single lock mechanism and a double lock mechanism; and at least one electronic lock configured to selectively unlock at least a portion of the mechanical lock upon receipt of the proper passcode from the cuff key. The power needed to operate the electronic lock, preferably a solenoid or other actuator, is received directly or indirectly from the cuff key so that the cuff need not possess a battery. 
         [0008]    The cuff may include a solid state memory device, for example, to store at least one passcode for comparison with the received passcode from the cuff key. Additional passcodes may be uploaded to the cuff to permit different keys access to the cuff or different levels of access to the cuff. The cuff may also be configured to receive and retain a serial number identifying the key used to open or unlock the cuff. Similarly, the cuff may be uploaded with a black list passcode specifying a passcode that is not authorized to unlock the electronic lock. The passcode is preferably a digital code which can be processed with a digital micro-processor. 
         [0009]    In another embodiment of the invention, the lock includes a cuff housing; a ratchet pivotably coupled to the housing; a lock mechanism configured to restrict rotation of the ratchet about the cuff housing; an electronic lock configured to restrict or otherwise prevent the lock mechanism from being unlocked without the appropriate electronic key; and a processor configured to: store at least one passcode; receive a passcode from a key; and unlock at least one of the one or more electronic locks if the received passcode matches the stored passcode. The lock mechanism may include what are referred to as a single lock mechanism and a double lock mechanism. The electronic lock may include a first electronic lock and a second electronic lock. The first electronic lock generally restricts movement of the single lock mechanism, and the second electronic lock restricts the movement of at least the double lock mechanism. 
         [0010]    The single lock mechanism generally includes a pawl that is biased onto the ratchet. The teeth of the pawl and ratchet are engaged in such a manner that the ratchet cannot be opened or otherwise removed from a prisoner&#39;s wrist without the appropriate electronic key. The pawl can only be pulled away from the ratchet with a lifter arm when acted on by a key. The first electronic lock includes an actuator that prevents the lifter arm from disengaging the pawl from the ratchet when locked, and permits the lifter arm to disengage the pawl from the ratchet when unlocked. The double lock mechanism includes a bolt configured to prevent the pawl from disengaging the ratchet when locked, and permit the pawl to disengage the ratchet when unlocked. The second electronic lock includes an actuator configured to prevent the bolt from disengaging the pawl when the second electronic lock is locked, and permit the bolt to disengage the pawl when unlocked. As discussed above, the power required to drive the one or more actuators is derived from the key since the lock has no internal power source. 
         [0011]    In another embodiment, the invention features an electronic lock having at least one actuator coupled to a mechanical lock; memory configured to store at least one passcode; and a processor configured to: receive a passcode from a key; compare the received passcode to the stored passcode; and activate the at least one actuator to unlock the mechanical lock, if the received passcode matches the stored passcode. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    The present invention is illustrated by way of example and not limitation in the figures of the accompanying drawings, and in which: 
           [0013]      FIG. 1  is a pair of electronic shackles; 
           [0014]      FIG. 2  is an exemplary electronic cuff, in accordance with one embodiment of the present invention; 
           [0015]      FIG. 3  is an exemplary electronic cuff key, in accordance with one embodiment of the present invention; 
           [0016]      FIG. 4  is a partial cross section of an electronic cuff in a single lock configuration, in accordance with one embodiment of the present invention; 
           [0017]      FIG. 5  is a partial cross section of an electronic cuff as the single lock is disengaged, in accordance with one embodiment of the present invention; and 
           [0018]      FIG. 6  is a partial cross section of an electronic cuff in a double lock configuration, in accordance with one embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0019]    The preferred embodiment of the present invention is an electronic restraint system including an electronic shackle or cuff and corresponding electronic key. Illustrated in  FIG. 1  is an electronic shackle  100  for enhancing the restraint of an individual and the safety of law enforcement personnel. The shackle  100  includes a pair of metal cuffs  102  or manacles adapted to encircle and confine the wrist or ankle of a person in the custody of law enforcement, this person being referred to herein as a prisoner. Each cuff  102  includes a cheek plate  104 , ratchet  106  pivotably attached to the cheek plate by means of hinge  109 , and a primary keyway  120  configured to receive a cuff key. The cheek plate  104  conceals a pawl with teeth  130  that engage the teeth  108  of the ratchet  106 . The cuffs  102  are flexibly coupled together with a chain  110  or bolt and swivel eyes  112  to bind the prisoner&#39;s wrists or ankles together. 
         [0020]    Referring to  FIG. 2 , each cuff  102  comprises a cheek plate  104  of hardened-steel for housing one or more mechanical and electronic locks, a ratchet  106  rotatably attached to the cuff housing by means of a pivot point  109 , a primary keyway  120  sized to receive a cuff key to disengage a single lock mechanism and double lock mechanism, and a secondary keyway  220  sized to receive the pin of a cuff key to engage the double lock mechanism. In accordance with some embodiments, the cuff further incorporates one or more electronic locks including a first electronic lock  260  and a second electronic lock  270 , each of which is electrically coupled to a passcode processor  250  protectively concealed within the cuff. 
         [0021]    Illustrated in  FIG. 3  is an exemplary cuff key  300 , which functions at both a mechanical level and an electrical level to open the electronic restraint system. In the preferred embodiment, the lower portion  310  of the cuff key comprises a form of barrel key with a hollow, cylindrical shaft  312  and a rectangular tooth or bit  316 . The barrel  310  is sized to fit within the primary keyway  120  and over a protrusion  122  that juts into the primary keyway from the inside of the cuff. The rectangular tooth or bit  316  is configured to turn within the cuff housing and unlock the single lock and double lock mechanisms. In addition, the upper portion of the cuff key includes an eye hole  322  and a pin  320  adapted to engage the double lock mechanism and the second electronic lock when inserted into the second keyway  220 . The central portion of the cuff key includes a passcode generator  350  for communicating an internal passcode to the cuff as well as a battery  360  configured to provide operational power to the passcode generator  350 , the passcode processor  250 , the first electronic lock  260 , and the second electronic lock  270 . 
         [0022]    Illustrated in  FIG. 4  is a partial cross section of a cuff with the single lock mechanism engaged (i.e., locked) and the double lock mechanism disengaged (i.e., unlocked). The cuff includes a housing defined by wall  402 , a ratchet  106 , a pawl  410  with spring  412 , a lifter arm  420 , and a bolt  430 . Consistent with a conventional cuff with the single lock engaged, the spring  412  continually biases the pawl  410  downward toward the ratchet  106 . The pawl  410 , however, may be raised upward when the ratchet  106  is closed if and when the slopped faces of the ratchet&#39;s teeth  108  are forced from right to left. As such, the single lock mechanism of the present embodiment allows the ratchet  106  to freely rotate in a closing direction (counter-clockwise about hinge  109 ) toward the housing to enable law enforcement personnel to quickly immobilize a prisoner&#39;s wrist or ankle, for example. Due to the asymmetric shape of the teeth on the ratchet and pawl, however, the single lock mechanism generally prevents the ratchet  106  from rotating in an opening direction (clockwise) unless the single lock mechanism is first disengaged with the cuff key  300 . 
         [0023]    Illustrated in  FIG. 5  is a partial cross section of a cuff  102  as the single lock is disengaged. To mechanically disengage the single lock, the cuff key is inserted into the first keyway  120  and the key turned clockwise to engage a flange  423  on the lifter arm  420 . When turned beyond about 135 degrees, the key&#39;s bit  316  pulls the lifter arm  420  away from the ratchet  106  in a generally upward direction. When a torque sufficient to compress the spring  412  is applied, the lifter arm  420  pivots counter-clockwise about its axis  422 , which causes the distal end at the right to push the pawl  410  upward away from the ratchet. 
         [0024]    The preferred embodiment of the cuff further includes a double lock mechanism for added security. Illustrated in  FIG. 6  is a partial cross section of a cuff with both the single lock mechanism and double lock mechanism engaged. The double lock is engaged by inserting the cuff key&#39;s pin  320  into the secondary keyway  220  to push the bolt  430  to the right into a position directly between the pawl  410  and housing wall  402 , thereby preventing the pawl from being lifted away from the ratchet  106 . As such, the pawl  410  is held in place to prevent the ratchet  106  from either opening (loosened) or closing (tightened) until the double lock is subsequently disengaged. To disengage the double lock, the same cuff key used for the single lock is inserted into the primary keyway  120  and turned counter clockwise (opposite direction needed to unlock the single lock mechanism), which pushes the bolt  430  back to the left when the key&#39;s bit  316  engages a flange  630  on the bolt  430 . When pushed back to its initial station, the bolt  430  is once again clear of the pawl  410  to permit the pawl to retract from the ratchet  106 . 
         [0025]    The cuff  102  of the preferred embodiment further includes a first electronic lock  260  and a second electronic lock  270 . The first and second electronic locks are configured to cooperate with and reinforce the single and double lock mechanisms, respectively. Both electronic locks are connected to the passcode processor  250  configured to compare the passcode received from a key to a stored passcode before disengaging the electronic locks. The passcode is communicated to the processor  250  by means of one or more electrical contacts  314  in the cuff key&#39;s bit  316  and corresponding electrical contacts in one or more of the keyway  120 ,  220 . When the first electronic lock  260  is engaged, for example, the single lock mechanism can only be opened when the processor  250  receives the proper security code from a cuff key inserted into the primary keyway  120 . The electronic cuff cannot, therefore, be opened by a standard cuff key even though it possesses the same physical shape and dimensions as the electronic cuff key  300  depicted in  FIG. 3 . 
         [0026]    The first electronic lock  260  is automatically engaged when the single lock mechanism is engaged (i.e., when the ratchet engages the pawl), and automatically disengaged when the proper key is inserted and/or turned clockwise in the primary keyway  120 . Similarly, the second electronic lock  270  is automatically engaged when the double lock mechanism is engaged via the second keyway  220  (i.e., when the bolt is slid behind the pawl), and automatically disengaged when the proper key is inserted and/or turned counter-clockwise in the first keyway  120 . 
         [0027]    Referring to  FIG. 4  again, the first electronic lock  260  includes a first actuator while the second electronic lock  270  includes a second actuator, both of which are connected to the passcode processor  250 . In the preferred embodiment, the actuators are electromagnetic solenoids although various other types of linear and rotary actuators known to those skilled in the art may be employed. The first actuator includes a coil  450  and a retractable projection  452 . When engaged, the projection  452  extends into the path of the lifter arm  420 , thereby preventing the lifter arm from pulling the pawl  410  away from the ratchet  106 . 
         [0028]    Referring to  FIG. 5  again, if and when the first electronic lock is disengaged, the processor  250  applies a power signal to the first solenoid  260 , which causes the projection  452  to be temporarily retracted. When retracted, the lifter arm  420  may be turned counter-clockwise and the pawl  410  lifted. Without the proper key, the projection  452  remains extended to prevent a key from turning the lifter arm  420  to open the ratchet. 
         [0029]    Referring to  FIG. 6  again, the second solenoid  270  also includes an electromagnetic coil  460  and a projection  462  adapted to physically obstruct the bolt  430  from sliding in an unlocking direction without the proper cuff key. If and when the second electronic lock is disengaged, the processor  250  applies a power signal to the second solenoid  270 , which causes the projection  462  to be retracted from a recess in the bolt. With the projection  462  clear of the bolt  430 , the bolt may be manually slid to the left and clear of the pawl  410 . Without the proper key, the projection  462  secures the bolt  410  to prevent a key from disengaging the second lock mechanism. 
         [0030]    In accordance with some embodiments, the power to actuate the first and second solenoids is provided by the cuff key  300 , which includes a portable energy source including one or more batteries  360 . The power signal may be transmitted serially after the passcode is transmitted to the cuff  102 , transmitted in parallel via a second channel operably coupling the key and passcode processor, or communicated to the cuff via a capacitive or inductive link. The cuff  102  in the preferred embodiment, however, does not include any internal energy source. 
         [0031]    The passcode processor  250  in the preferred embodiment is a solid state micro-processor such as a Programmed Integrated Circuits (PIC), for example. The processor authenticates the passcode by comparing the passcode received from the key to one or more approved passcodes retained in on-board memory in the cuff&#39;s passcode processor  250 , for example. A passcode is preferably a 256 or 512 bit digital code or combination representing an alphanumeric string of characters. The passcode may be stored to on-board memory when the cuff is manufactured; programmably written to memory using an erasable programmable read-only-memory (EPROM), for example; or a combination thereof. 
         [0032]    The set of passcodes with which the cuff  102  can be opened may consist of a single passcode associated with one or more keys, or comprise multiple passcodes associated with different geographic areas or the different levels of a law enforcement organization. For example, there may be a first passcode associated with the key of an officer; a second passcode associated with a local law enforcement department, a third passcode associated with a county law enforcement department; a fourth passcode associated with a state law enforcement department; or any combination of the above. This avoids the problems associated with the universal key in traditional cuffs. The preferred embodiment also isolates problems due to lost keys, for example, since the loss of a key used in one police department does not affect another department using a different passcode. 
         [0033]    In some embodiments, the cuff  102  is further adapted to retain a black list including passcodes that are barred from unlocking the cuff, thereby providing a mechanism for neutralizing the passcodes associated with keys that are lost or stolen, for example. The authorized passcodes and black list codes may be periodically uploaded to the cuff using a docking station, such as a cradle maintained by the law enforcement office or manufacturer. 
         [0034]    The electronic cuff key  300  in the preferred embodiment comprises a traditional skeleton key or barrel key with one or more bits  316  having one or more electrical contacts  314 ; a memory for retaining one or more passcodes; a processor  350  or circuit board for generating the passcode; one or more batteries  360  or other power source; and a cylinder  370  to house the batteries. The key  300  should be sufficiently large to prevent a stolen key from being easily concealed by a prisoner during a pat-down search, for example. This may be effectively achieved using a key with two or more AA or AAA batteries, for example. The key may have assigned to it a unique serial number that is also communicated to the cuff each time the cuff is unlocked. 
         [0035]    In some embodiments, the cuff key  300  includes a miniature recharging apparatus in the key, the recharging apparatus being consistent with the recharger used in hands-free headsets for cellular phones. A light emitting diode may be used as a low battery charge level indicator, and/or an audible alert used to notify the user of a low battery charge level or malfunction. When low, the batteries can then be recharged with a AC to DC converter, which could save the law enforcement departments the expense of replacing batteries. 
         [0036]    In some embodiments, the key and/or cuff includes a light emitting diode (LED) whose light level can be used to indicate to law enforcement personnel whether the first or second locking mechanism has been properly engaged and/or disengaged. Similarly, the cuff key  300  and/or cuff  102  may include an audible alarm for generating a beep to indicate when the electronic cuff is locked and/or unlocked. 
         [0037]    In some additional embodiments, the cuff  102  is adapted to measure, record, and upload information about the cuff and key usage. Information indicating the degree to which the cuff is locked may also be recorded to enable law enforcement to reconstruct the conditions under which cuff was applied to a prisoner. That is, the cuff  102  is adapted to indicate the position of the ratchet relative to the housing, thus indicating how much or how little pressure was used to constrain the prisoner&#39;s wrist within the cuff. The position of the ratchet may be measured and recorded in terms of the number and position of the ratchet teeth  108  that engage the pawl  410  when the cuff is secured in the single or double locked position. The information may further include a timestamp and the information periodically uploaded to a cradle or docking station, for example. 
         [0038]    The information recorded by the cuff for subsequent download may further include the serial number of the previous one or more keys used to unlock the cuff. This information may then be stored in the cuff and retrieved if necessary to identify which key was used to unlock the cuff, determine the identity of the person to whom the key was assigned, and whether the individual with the key was authorized to unlock the cuff. 
         [0039]    The preferred embodiment of the invention herein is intended for use in a cuff or other restraint system. One skilled in the art, however, will appreciate that the invention is also applicable to numerous other locking applications including automobiles, homes, gates, filing cabinets, lock boxes, safes, chests, briefcases, padlocks, and trigger locks, for example. 
         [0040]    Although the description above contains many specifications, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the presently preferred embodiments of this invention. 
         [0041]    Therefore, the invention has been disclosed by way of example and not limitation, and reference should be made to the following claims to determine the scope of the present invention.