Abstract:
The invention is directed at an electronic lock assembly which is operable by a suitably programmed electronic key. The electronic lock assembly includes a cylinder type locking mechanism, where a solenoid and plunger is provided to electronically lock and unlock a key cylinder, thereby selectively allowing rotation of the key cylinder for operation of the locking mechanism. To prevent rotation of the key cylinder and loading of the solenoid plunger prior to the solenoid receiving an authorized signal to retract the plunger, a stop mechanism is provided which only allows rotation of the key cylinder in predetermined coordination with operation of the solenoid.

Description:
TECHNICAL FIELD 
     This invention relates to an electronic lock assembly which is operated by inserting of an authorized electronic key. Rotation of the lock cylinder is inhibited until operation of the lock assembly is desired. Once the key is rotated, the key cannot be removed from the lock cylinder until the lock cylinder is rotated back to its original position, thereby giving the electronic lock the feel of a mechanical lock. 
     BACKGROUND OF THE INVENTION 
     In many environments, such as apartment houses, multi-family dwellings, condominiums or the like, the transient nature of residents present problems in using conventional locking mechanisms in association with a door having a latch which is operable from both sides of the door by means of a handle or the like. In such environments, keys usable to unlock conventional lockable latching mechanisms are easily replicated, thereby potentially compromising the security provided by the lockable latching mechanism. As tenants or occupants move from such an environment, a key or copy of the key can be retained, though the former tenant or occupant is no longer entitled to access thereto. Similarly, if maintenance or repair procedures require access by other personnel, maintaining security may again be compromised if keys are duplicated or not returned by the repair or maintenance personnel. Thus, security standards in such environments may require that the lock be removed in its entirety and replaced, or the lockable latching mechanism is swapped with another mechanism from another unit to ensure security. Another alternative is to have the lockable latching mechanism re-keyed such that the previous key will not operate the mechanism. In each of these situations, the replacement, re-keying or swapping of the lockable latching mechanism is costly, both in terms of expense and/or personnel resources, and/or presents a time consuming and inefficient process for ensuring security. 
     Attempts have therefore been made to provide enhanced security by providing an electronic lock which employs a programmable processor which can be programmed to only allow operation of the lock if a valid key is used. Thus, upon a tenant or occupant leaving a premises, the electronic lock can simply be reprogrammed so that the old key will not operate the lock, thereby eliminating the need to replace or re-key the lock. Although electronic locks using card readers, key pads or contact activated data ports are known, various deficiencies in such electronic lock assemblies have been found, and such systems have generally been cost prohibitive or complex, thereby limiting widespread use in such environments. 
     SUMMARY OF INVENTION 
     Based upon the foregoing, the present invention is directed at an electronic lock assembly which is operable by a suitably programmed electronic key. The electronic lock assembly includes a cylinder type locking mechanism, where a solenoid and plunger is provided to electronically lock and unlock a key cylinder, thereby selectively allowing rotation of the key cylinder for operation of the locking mechanism. To prevent rotation of the key cylinder and loading of the solenoid plunger prior to the solenoid receiving an authorized signal to retract the plunger, a stop mechanism is provided which only allows rotation of the key cylinder in predetermined coordination with operation of the solenoid. 
     These and other aspects of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective exploded schematic view showing an electronic deadbolt locking mechanism according to an embodiment of the invention; 
     FIG. 2 is a perspective schematic view of a cylinder housing assembly; 
     FIG. 3 is an exploded perspective view of the cylinder housing assembly as shown in FIG. 2; 
     FIG. 4 is a side elevational view of the cylinder plug according to this embodiment; 
     FIG. 5 is a cross sectional view taken along line  5 — 5  in FIG. 4; 
     FIG. 6 is an exploded view of the solenoid and plunger according to this embodiment; 
     FIG. 7 is a side elevational view of a sidebar according to this embodiment; 
     FIG. 8 is a cross sectional view taken along line  8 — 8  in FIG. 7; 
     FIG. 9 is an exploded respective view of the outside cylinder housing and cylinder plug according to this embodiment of the invention; 
     FIG. 10 is an alternate exploded perspective view of the outside housing and cylinder plug as shown in FIG. 9; 
     FIG. 11 is a perspective view of an electronic key useable to operate the electronic lock assembly according to the invention; and 
     FIG. 12 is an alternate embodiment of the invention showing a modified outside housing assembly  30 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Turning now to FIG. 1, the present invention will be described in conjunction with an electronic deadbolt assembly. As shown in FIG. 1, the deadbolt assembly may include a face plate  12 , which will normally be visible from the edge of the door. A front case  14  may be joined to the front plate  12 , and a rear case  16  is provided in telescopic adjustable relationship to the front case  14 . A deadbolt  18  is provided in slideable relationship within the front case  14 , and is coupled to a swivel generally indicated at  20 . The swivel mechanism  20  may include a pair of ears  22  connected to a link  24 . The link  24  is connected to the bolt  18  in a suitable fashion, and operation of the deadbolt  18  between a fully extended position and a retracted position is provided by means of a spindle  26  in a known fashion. In general, spindle  26  is engaged between inner and outer cylinders, wherein upon rotation of the cylinders, spindle  26  rotates to cause corresponding movement of the swivel  22  and link  24  and movement of bolt  18  between extended and retracted positions. The structures of the front case  14 , rear case  16  and operation of the deadbolt is typical, and details of this construction and operation may be modified in accordance with known mechanisms. 
     The deadbolt assembly  10  as shown in FIG. 1 further comprising an outside housing assembly  30 , which includes an outside rose  32  and a lock cylinder or cylinder plug  34 , which will be described in more detail hereafter. The cylinder plug  34  includes a keyway  36 , into which an electronic key  130  is inserted for operation of the deadbolt assembly  10 . The deadbolt assembly  10  further comprises an inside turn assembly generally designated  50 , over which an inside rose  52  is positioned. A thumbturn  54  is coupled to inside turn assembly  50  such that operation of the thumbturn  54  will in turn cause rotation of the thumbturn extension  56  rotating, in turn, an outwardly extending portion  58  which engages spindle  26  in the deadbolt assembly. Thus, upon rotation of the thumbturn  54  on the interior of the door, rotation of the thumbturn extension  56  will in turn cause rotation of extension  58  so as to operate spindle  26  causing corresponding extension or retraction of the deadbolt  18  in a known fashion. The deadbolt  18  in its extended position engages a strike  60  positioned on the doorjamb, and an associated strike box  62 . A strike reinforcer  64  may be provided to enhance the structural integrity and security of the deadbolt latch. 
     It should be recognized that operation of a thumbturn in conjunction with the inside turn assembly  50  to selectively extend or retract the deadbolt  18  is generally known, and will not be described further. 
     Turning now to FIGS. 2 and 3, the outer housing assembly is shown in more detail. The outside housing assembly  30  includes a cylinder housing cap  70  having a hole  71  through which the cylinder plug  34  is exposed at the outside of the lock assembly. In this manner, keyway  36  will be exposed on the exterior of the lock assembly for access by an electronic key. The cylinder plug  34  is dimensioned to extend within a cylinder outside housing  72 , and is selectively rotatable within cylinder outside housing  72  by means of an authorized electronic key positioned within keyway  36 . The cylinder outside housing  72  is removed from FIG. 2 for clarity of other elements situated within housing  72 . After insertion of the cylinder plug  34  into housing  72 , the rearward or opposing end of cylinder plug  34  disposed opposite keyway  36  engages a cylinder tailpiece  74  which is retained thereon by a retaining ring  76 . The cylinder tailpiece  74  engages the swivel  26  associated with the deadbolt latch assembly as described in FIG.  1 . In this manner, rotation of the cylinder plug  34  will in turn cause rotation of the swivel  26  and extends and retracts the deadbolt  18  as previously described. There also may be provided in association with the rearward end of the cylinder plug  34  a pick cap  78  which helps to prevent picking or tampering with the lock assembly. 
     Within the outside cylinder housing  72  is positioned a solenoid assembly generally indicated at  80 , including a solenoid plunger  82  which is spring biased to an outward position by means of solenoid spring  84 . As seen in FIG. 6, the solenoid assembly  80  may comprise a supporting frame  81  in association with a solenoid bobbin  83  to which electrical connection is made via pins  85 . The bobbin  83  is inserted and retained therein through an opening in the frame  81 . Other suitable configurations to provide solenoid assembly within the lock architecture would be recognized by those of ordinary skill, and are contemplated by the invention. Associated with the solenoid  80  is a flex assembly  86  which includes a flexible electrical connecting interface  88 , which carries electrical signals to a microprocessor housed within the inside turn assembly  50  as described with reference to FIG.  1 . The flex assembly  86  also couples power to the solenoid  80  from a battery power source housed within inside turn assembly  50  via clip (not shown) positioned at the end of flexible electrical connecting interface  88 . An electrical connecting board or stiffener  92  is provided to support various components in conjunction with the flex assembly  86 , including an LED  94 , a ground clip  96  and a data transfer spring  98 . A light pipe  100  is associated with the LED  94  to transmit light from LED  94  to the exterior of the electronic lock through an aperture  102  formed in the cylinder housing cap  70 . The LED will provide information to the user, as to whether an authorized key is being used (green indicating light), or whether an unauthorized key has been inserted into the electronic lock assembly (red indicating light) as an example. The LED  94  can be multi-colored to allow various light signaling indications to the user. The ground clip  96  electrically grounds the assembly to the outside cylinder housing  72  when the flex and solenoid assembly is inserted into the outside cylinder housing  72 . The data transfer spring  98  extends to be electrically coupled in association with a cylinder pin assembly  104  which is housed in association with the cylinder plug  34 . The cylinder pin assembly  104  extends to a position to be accessible at the front face of the cylinder plug  34  when positioned therein, through an access hole  106 . Preferably, the cylinder pin assembly  104  extends to be flush with the front face of cylinder plug  34 . In operation, when an electronic key is inserted into keyway  36 , a contact pin  146  associated with the electronic key contacts the cylinder pin assembly  104  which is in electrical wiper contact with the data transfer spring  98  to communicate data from the electronic key through the flex assembly  86  to the microprocessor. If an authorized key is used, the microprocessor will in turn send a signal through the flex assembly  86  to the solenoid assembly  80  to selectively withdraw the solenoid plunger  82  against the force of bias spring  84 . 
     As only an Authorized electronic key will provide data to initiate actuation of the solenoid by the microprocessor, rotation of the cylinder plug is otherwise prevented by a rotation preventing member or sidebar  110 . The sidebar  110  includes a sidebar spring  112  which biases the sidebar  110  into engagement with the cylinder plug  34 , to prevent rotation of the cylinder plug  34  until actuation of the solenoid and withdrawal of the plunger  82 . Sidebar spring  112  may comprise one or more of many types of springs and is not limited to the leaf spring type shown. Although not shown, a pair of coil springs could also be used as the sidebar spring  112 . As seen in FIGS. 4 and 5, the cylinder plug  34  includes an elongated slot  120  into which a bottom portion of the sidebar  110  is positioned. As seen in FIG. 8, the bottom portion of the sidebar comprises a contoured point  116 , which is substantially matched to engage the slot  120  formed in the plug cylinder  34 . As shown in FIG. 8, the contoured point  116  maybe provided with angled portions, which in this embodiment are approximately 45°, to substantially match the configuration of the slot  120 , which in this embodiment is formed as an approximate 90° angled slot as seen in FIG.  5 . Upon attempting rotation of the cylinder plug  34 , and due to the configuration of the slot  120  in association with the bottom portion  116  of the sidebar  110 , the sidebar  110  will be urged outwardly from the slot  120  against bias spring  112 . To prevent such movement of the sidebar  110  unless an authorized key is inserted into the cylinder plug  34 , the plunger  82  of the solenoid engages the slot  114  formed in the side portion of the sidebar  110 . As seen in FIG. 8, the slot  114  may also be configured to have angled sides at approximately 45°, into which the plunger  82  is positioned in its normally extended position. When the plunger  82  is positioned within the slot  114 , the sidebar  110  is not able to move outwardly relative to the slot  120  formed in the cylinder plug  34 . Thus, rotation of the cylinder plug  34  is prevented, thereby effectively locking the deadbolt mechanism, and not allowing retraction of the deadbolt  18  accordingly. When an authorized electronic key is inserted into the cylinder plug  34 , and a data signal is generated by a microprocessor to actuate the solenoid  80 , the plunger  82  is withdrawn from the slot  114  for a predetermined period of time. As a user rotates the authorized electronic key, the sidebar  110  will be urged out of the slot  120  in the cylinder plug  34  against the force of the bias spring  112 , to thereby selectively allow rotation of the cylinder plug and actuation of the deadbolt mechanism to retract the deadbolt  18  and allow opening of the door. After actuation of the deadbolt mechanism by an authorized electronic key, the cylinder plug  34  is rotated back to its initial position, and the sidebar spring  112  urges sidebar  110  back into slot  120  in the cylinder plug  34  and the solenoid plunger  82  into slot  114 , to thereby lock rotation of the cylinder plug at the home position until further actuation. 
     In this embodiment of the invention, upon insertion of an authorized electronic key into the cylinder plug  34 , the microprocessor will withdraw the solenoid plunger from the slot  114  for a predetermined amount of time. It may be desirable to provide a short delay occurring between actuation of the solenoid and return of the plunger to its normally extended position. The microprocessor may therefore be programmed to cause retraction of the plunger to accommodate a slight delay which may occur between insertion of an authorized electronic key and the user rotating the cylinder plug  34  for actuation of the deadbolt mechanism. If the user does not rotate the cylinder plug  34  after insertion of an authorized electronic key, the system will time out and the plunger will return to its normally extended position to engage slot  114  and lock the mechanism accordingly. 
     With respect to the electronic lock assembly as previously described, it is desirable to selectively prevent rotation of the cylinder plug  34  prior to withdraw of the solenoid plunger  82  from its rotation inhibiting position with respect to the cylinder plug  34 . In this manner loading of the solenoid plunger  82  prior to the solenoid assembly  80  receiving a signal to retract the plunger  82  is prevented. Proper operation of the lock assembly is thereby facilitated, and no undue forces are applied to these mechanisms which could cause damage or limit the useful life of the mechanism. Turning to FIG.  9  and FIG. 10, an embodiment of a stopped mechanism to accomplish this objective is shown with respect to the outside housing assembly  30  and cylinder plug  34 . In this embodiment, the cylinder plug  34  is formed with an opening  150  formed in the cylinder plug  34  to accommodate a ball bearing  152  therein, with ball bearing  152  movable within the opening  150 . Referring back to FIG. 5, the opening  150  is seen to extend from an outer surface of the cylinder plug  34  to a position in which a portion of opening  150  intersects with the key way  36  formed in cylinder plug  34 . In this manner, upon introduction of the ball bearing  152  into opening  150 , a portion of ball bearing  152  can extend into key way  36 . As seen in FIG. 10, the outside housing  30  is also formed to include a groove  154 , positioned to cooperate with the ball bearing  152  upon assembly of the cylinder plug  34  with housing  30 . Upon assembly of the cylinder plug  34  into housing  30  with ball bearing  152  positioned within opening  150 , it should be recognized that ball bearing  152  is moveable between an intersecting position with respect to key way  36 , and a non-intersecting position when bearing  152  is fully positioned within the groove  154  formed in housing  30 . In this manner, upon insertion of an electronic key  130  into key way  36 , the key will interact with ball bearing  152  to force bearing  152  into engagement with the groove  154  formed in housing  30 . When bearing  152  is forced into engagement with groove  154 , rotation of the cylinder plug  34  is inhibited prior to withdrawal of the solenoid plunger  82  from its rotation inhibiting position. As seen in FIG. 11, the electronic key  130  includes an outwardly extending portion  137  which is inserted into the key way  36  in a normal fashion. A slot or dimpled portion  138  is formed within portion  137 . Upon full insertion of key  130  into key way  36  the dimple portion  138  mates with the ball bearing  152  to allow movement of ball bearing  152  out of groove  154 . In this way, upon full insertion of the key  130  into key way  36 , so as to actuate the solenoid assembly  80  and retract solenoid plunger  82  as previously described, the ball bearing  152  will be relieved from a outwardly bias position created by interference from key  130  by means of the dimpled portion  138  to allow rotation of the cylinder plug  34  to operate the lock mechanism. 
     In an alternative embodiment of the present invention as shown in FIG. 12, the stop mechanism according to the invention is comprised of an opening or hole  160  formed in a sidewall of the housing  30  into which ball bearing  152  is positioned and spring biased by means of a spring  164  and retaining cap  166  into the intersecting position within opening  150  in the cylinder plug  34  as previously described. In this embodiment, upon insertion of key  130  into key way  36 , the key will again intersect with a portion of ball bearing  152  to force it into engagement with a portion of the housing  30  to thereby prevent rotation of the cylinder plug  34  in a manner similar to the previous embodiment. Upon full insertion of key  130 , and seating of the ball bearing within a dimpled portion  138  as previously described, rotation of the cylinder plug  34  is enabled. The seating of the ball bearing  152  within a dimpled portion  138  prevents withdrawal of the key  130  from cylinder plug  34 . Accordingly, the key cannot be removed from the lock cylinder until the lock cylinder is rotated back to its original position allowing ball bearing  152  to be pushed radially outward and allowing removal of key  130 . This locking feature thereby gives the electronic lock assembly the feel of a mechanical lock. As with this embodiment, it should be recognized that other suitable stop mechanisms configurations are possible to selectively prevent rotation of the cylinder plug  34  prior to retraction of the solenoid plunger  82  in the desired manner. Such alternate stop mechanisms are contemplated and within the scope of the present invention. 
     It should also be recognized that in both embodiments of the invention the ball bearing will prevent the key  130  from being removed from the keyway  36  after rotation of the cylinder plug  34  from its home position in operating the lock assembly as described above. Upon rotation of the cylinder plug  34 , the ball bearing  152  will be seated within the dimpled portion  138  of key  130 , such that  130  cannot be removed from the cylinder plug  34  until it is back in its home position, and ball bearing is moveable out of dimpled portion  138 . 
     Whereas the invention has been shown and described with reference to particular embodiments thereof, it should be realized that there maybe many modifications, substitutions or alterations thereto, which are encompassed within the scope of the invention. The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows: