Two-key locking system
[451 Apr. 15, 1975 1 TWO-KEY LOCKING SYSTEM v [75] inventor: John D. McLaughlin, Raleigh, NC.  
 [73] Assignee: Ellock International, Inc., Raleigh,  
 [22] Filed: Mar. 28, 1974 [21] Appl. No.: 455,750  
 [52] U.S. Cl. 70/280; 317/134; 340/274 [51] Int. Cl E05b 47/02 [58] Field of Search 70/280; 317/134; 340/274 [56] References Cited UNITED STATES PATENTS 2/1955 Schampel 70/280 9/1964 Durant 70/107 Priniary ExaminerAlbert G. Craig, Jr. Attorney, Agent, or Firm--Prutzman, Hayes, Kalb &amp; Chilton tween open and closed positions and locking members associated with each closure is provided with electrically actuated locking and unlocking coils operable for driving the locking member between its locking and unlocking&#39;positions; a first control switch in the central control area and a second control switch in series with and remotely located from the first switch. The control switches are key-actuated and electrically connected through a security switch unit to the unlocking coil for actuation thereof upon closing of the first and second switches to drive the locking member to its unlocking position. A holding circuit is operatively associated with the locking coil and activated in response to&#34; movement of the locking member to its unlocking position and movement of the access closure to an open position. The locking coil is conditioned for actuation upon return of the access closure to its closed position. The security switch unit is operatively controlled from the interior of the secure area and controls the operation of the holding circuit. The security unit is operative to interrupt both the locking and unlocking circuits to secure the secure area by preventing key-actuated operation of the locking member and controlling operation of an alarm system.  
 12v Claims, 3 Drawing Figures 1 TWO-KEY LOCKING SYSTEM BRIEF SUMMARY OF THE INVENTION The present invention relates generally to security systems for controlling access to restricted areas such as motel rooms or selected areas of buildings such as bank vaults, areas of high danger and the like. More particularly, the invention is concerned with a new and improved electrical key-actuated security locking system whereby only an authorized individual or class of individuals is able to gain access to the interior of a specified area.  
  An object of the present invention is to provide a new and improved security locking system particulary adapted for use with a central control area and a remote secure area to which access is limited. Included in this object of the provision for double key switches within both the central control area and the remote secure area, the switches being operatively interconnected so that actuation of both switches is required in order to gain access to the interior of the secure area.  
  Another object of the present invention is to provide a new and improved electrical key-actuated security locking system of the type described that provides a central control over the primary access switch to a remote secure area without hampering egress from the area-Included in this object is the provision for automatic door locking as an authorized person either enters or leaves the secure area.  
  Still another object of the present invention is to provide a security locking system of the type described that includes a security device manually controlled from within&#39;the interior of the remote secure area to prevent access thereto even by a person using a duplicate of the authorized key.  
  A further object of the present invention is to provide a new and improved electrical key-actuated security locking system wherein the actuation of two keyoperated switches in different locations provides an unlocking function in order to gain access to a remote secured area and wherein an automatic holding circuit is provided to assure automatic locking of the door to the secured area when the door closes. Included in this object is the provision for an automatic holding circuit that is activated in response to opening of the door so that the automatic locking of the door will occur as soon as the door reaches its closed position.  
  A still further object of the present invention is to provide a new and improved security locking system of the type described that includes a service bypass system &#39;to bypass the key-actuated switches to permit servicing of the remote secure area. However, included in this object is the provision for a security switch that is operable from the interior of the secure area to prevent actuation of the service bypass as well as access to the secure area by a person using the correct key in the double key switches.  
  Still another object of the present invention is to provide a locking system that includes a bolt having a manually operable feature that will permit unlocking and relocking of a secure area by a person within that area in the event of a power failure. Additionally, the system provides an emergency bypass at the central control area to bypass the security latch in the event of an emergency condition such as the illness of a person within the remote secure area.  
  A still further object of the present invention is to provide a security unit within the key-actuated security locking system that is operable to activate an alarm system upon operation of the key-actuated switches by an unauthorized person.  
  Other objects will be in part obvious and in part pointed out in more detail hereinafter.  
  These and related objects are accomplished in accordance with the present invention by providing a new and improved electrical key-actuated security locking system comprised of a control area, a remote secure area including an access closure movable between open and closedpositions, a power source and a locking member associated with the closure and movable between a locking position and an unlocking position to permit movement of the access closure into and out of its closed position. The system further includes electrically actuated locking and unlocking means operable for driving and locking member between its locking and unlocking positions. A first switching means is provided at the central control area connected to the power source. A second key-actuated switching means is connected in series with and is remotely located from the first switching means. The second switching means is electrically connected to the unlocking means through a security unit for actuation of the unlocking means upon closing of the first and second switching means. A holding circuit means is provided in operative association with the locking means and is activated in response to&#39;movement of the locking member to its unlocking position and movement of the access closure to an open position to condition the locking means for activation upon return of the access closure to its closed position. The security unit is also disposed intermediate the second switching means and the unlocking means and completes the circuit therebetween. The security unit includes switches that control the operation of the holding circuit means from the interior of the secure area and are adapted to interrupt both the locking and the unlocking circuits to secure the secure area by preventing key-actua&#39;ted operation of the locking member and operation ofan alarm system.  
  A better understanding of the invention will be obtained from the following detailed description and the accompanying drawing which set forth an illustrative embodiment indicative of the way in which the principles of the invention are employed.  
 BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:  
  FIG. 1 is a block diagram flow sheet of a typical arrangement for .the security locking system of the present invention;  
 FIG. 2 is a sectional view, partially broken away and partially in section, of a bolt latch suited for use in the system of FIG. 1&#39;, and  
  FIG. 3 is a schematic of a circuit diagram for the electrically operated security locking system of FIG. 1.  
 DESCRIPTION OF A PREFERRED EMBODIMENT registration desk of a motel and a remote secure area 12 such as an individual motel room or an entire restricted area of a building. As will be appreciated, multiple isolated secure areas can be controlled from the central control area with separate controls located in each of these areas. However, for purposes of illustration and ease of understanding, only one such remote area 12 will be discussed in detail.  
  As shown, the control area is provided with a first control for each area, such as a first key control 14 or similar control that is operable solely by the attendant within the central control area. Where the control is key actuated, the attendant can operate the control and then give the key to an authorized person allowed within the restricted area. That person may then proceed to the particular remote secure area 12 where the key can be used to actuate a second key control 16. The second key control is connected in series with the first control 14 through a security switching unit 18 to an unlocking unit 20 of the system. The security unit 18 is normally in a closed circuit condition since it is adapted for manual operation from the interior of the secure area so that, during normal operation, activation of the relatively remote controls 14 and 16 will immediately effect operation of the unlocking unit 20. The security switching unit 18 also controls an automatic holding or, arming portion 22 of the locking system such that, as the unlocked door to the secure area is opened, a locking unit 24 is automatically activated for locking the door as soon as the door returns to its closed position.  
  The security system of the present invention additionally includes a number of interior controls over the unlocking operation of the remote secure area. These controls are generally designated at 26 and permit a person within the interior of the secure area to activate the unlocking mechanism 20 to permit access by persons other than those in possession of the authorized key. Thus, the interior control 26 can operate in a manner similar to the dual key controls 14 and 16 and will provide both an unlocking and an automatic relocking of the door to the secure area. The interior control 26 includes a second aspect, preferably by a separate control means, namely that of providing an interruption between the dual key controls and the unlocking and locking units. A person within the interior of the secure area can control the operation of the security switching unit 18 so-as&#39;tov interrupt the circuit between the dual key controls and the unlocking unit 20 and automatically and simultaneously close the circuit between the dual key controls and an alarm system 28. In this manner, if a person attempts to operate the dual key controls 14 and 16, the security switching unit 18 will direct the signal to the alarm system 28. Further, as will be discussed in greater detail in connection with FIG. 2, a person within the interior of the secure area can manually unlock and lock the doorto the secure area so that the door can be readily unlocked and opened in the event of a total power failure.  
  It is another feature of the system that a service bypass 30 of the key controls is provided within the central control area 10. The service bypass 30 is manually controlled at the central control area 10 and operates through the security switch unit 18 to actuate the unlocking unit 20 for the remote secure area. Thus, maid service or the like can be provided to each remote area via the service bypass 30 without using the key controls 14 and 16. However, if a person within the interior of the secure area operates the security switch unit 18 so as to close the circuit to the alarm 28, the service bypass 30 is also connected to the alarm system and operation of the service bypass will be ineffective to operate the unlocking mechanism but instead will actuate the alarm system 28.  
  Since the security switch unit 18 is effective to interrupt both the key controls and the service bypass, an emergency bypass 32 is also provided within the central control area 10 in the event of a total emergency. The emergency bypass 32 connects directly to the unlocking unit 20 and is useful in the event the person within the secure area is incapacitated and has moved the security switch unit 18 to the alarm condition thereby rendering the dual key control system and the service bypass system ineffective to unlock the door to the secure area.  
  As will be appreciated, the dual control system permits ready access to a secure area by an authorized person. At the same time, an attendant in the central control area has full control over access via the dual control system and can render it ineffective even while a person is within the secure area. Such action by the attendant still permits persons within the area to leave and have the door automatically locked behind them. Further, persons within the secure area have manual control over the security switch unit and can use it as a night latch to prevent actuation of the unlocking and locking units except under total emergency conditions. Further, the locking system is provided with an automatic holding or arming circuit that holds the locking unit in a ready state and automatically effectuates locking of the security area whenever the door is closed.  
  Referring now to FIG. 2, there is illustrated a bolt latch construction which incorporates both the unlocking and locking features of the system of the present invention. In the particular embodiment illustrated, a bolt housing or enclosure 40 is shown as mounted within a wall, frame or the like 42 adjacent a closure 44 such as a door, window or the like. The bolt housing 40 is preferably constructed of a relatively heavy material with only a manual operating lever or knob 46 on the bolt 48 exposed through an elongated slot 50 for manual unlatching and relatching of the locking mechanism. As shown, tubular guides 52, 54 can be inserted in the respective frame 42 and closure 44 in coaxial alignment for slidably receiving the latching bolt 48. The guides are positioned so as to be in longitudinal alignment when the door or other closure 44 is in its closed position and such guides and the latching bolt itself are preferably made of a non-magnetic material to prevent location thereof by magnets or similar detecting apparatus. Within the bolt housing 40 there is provided an unlocking coil 56 in the form of a solenoid coil that operates on a metal rod or plunger 58 fixedly secured to the bolt 48 for movement therewith. Thus, upon activation of the unlocking solenoid coil 56, the rod 58 and bolt 48 are drawn to the left as viewed in FIG. 2, to fully retract the bolt 48 from the guide 54 implanted within the movable closure 44. Similarly, a locking coil 60 which might also be in the form of a solenoid may also be arranged so as to operate on the same metal plunger 58 to draw the plunger and bolt to the right, as viewed in FIG. 2, to effect the locking operation.  
  A cam member 62 fixedly secured to the bolt and plunger operates on the leaf 64 of a snap action switch 66 to sense the position of the bolt in either its locked or its unlocked position. A more detailed explanation of the functioning of the switch 66 will be provided in connection with the circuit diagram of FIG. 3. As will be noted, the bolt 48 may also be provided with a tubular sleeve 68 which is positioned so as to prevent axial displacement thereof but is sufficiently free of the main portion of the bolt to permit its rotation relative to the bolt 48. Thus, if an unauthorized person attempts to cut through the bolt 48, the sleeve 68 will simply rotate about the bolt giving little or no resistance to the operation of the saw, thus defeating the action of the unauthorized person.  
  Referring now to FIG. 3 of the drawing, one embodiment of a circuit diagram is shown therein as including an electrical power supply 80 which can be either alternating or direct current. For simplicity of description, the line 82 connected to the power source 80 will be referred to as the ground or return line. However, as will be appreciated, various components could be individually grounded to a common chassis and still operate as described. In the particular embodiment illustrated, the system includes three snap action switches controlled by and responsive to the position of the door or closure 44. Switches 84 and 86 are in a normally closed position when the door is closed and in an open position when the door is open. However, switch 88 leading to the automatic holding relay 22 operates in the opposite fashion so that the circuit is normally open when the door is in the closed position and will close as the door moves out of its closed position. Accordingly, the circuit diagram of FIG. 3 illustrates the position of the circuit with the door in its closed and locked condition.  
  As mentioned, the first key control 14 is located within the central control area and can be at a motel registration desk or the like. The control switch 14 is, in the preferred embodiment, a key-actuated switch lock that can take the form of a cylinder lock which controls an electrical switch mounted on the rear of the lock. Alternatively, the lock may be of a magnetic or electronic nature. The switch lock 14 is preferably of a SPST type and is configured so that the key can only be removed when the switch is in ;the on position. Thus, the key is held in the switch control 14 when in the of position and movement of the lock so as to move the switch to its on position will close the circuit from the power. source through the snap action door control switch 84 to the second key control 16 located in the remote secure area 12. The control person or attendant within the central control area can remove the key from thefirst key control switch 14 and give it to the authorized person allowed into the restricted or secure area 12. Alternatively, the control 14 could be a manually operated switch not requiring a key so long as it is controlled within the central control area 10. In either event, operation of the first control 14 will permit an authorized person to then proceed to the remote secure area 12 and use the key provided by the attendant to close the second key-actuated switch lock 16.  
  When the key is inserted into the second control switch lock 16, turned to complete the circuit and the pressure of turning the key is released, the key should automatically snap return to its original position since the lock in the remote secure area preferably should be spring loaded and the key can only be removed from control 16 after the lock has snapped back to its original position. This action will complete the circuit between the power source 80 and the unlocking coil 56 which is connected to the return or ground line 82. Thus, the actuation of the dual control switch locks 14 and 16 and the resultant energization of the unlocking coil 56 causes the bolt 48 to travel to the left as viewed in FIG. 2 and the door or other closure 44 to the secure area 12 to be unlocked. Since the snap action switch 66 mounted within the bolt enclosure 40 is controlled by the movement of the cam 62 carried by the bolt 48, the switch 66 is released to move to its closed position as the bolt 48 moves to its unlocked position. This effects an extension of the ground or return line 82 to the ground side of the door responsive switch 88 that is still in its open condition.  
  As the unlocked door is opened, the switch 84 positioned in series between controls 14 and 16 and the switch 86 in line with coil 60 move to their open position while the door control switch 88 connected directly to the power source 80 moves to its closed position, thus completing the circuit through the coil 90 of the automatic holding or arming relay 22. This relay is of the DPDT type and the energization of the relay coil 90 is effective to draw the wiper 92 toward terminal 94 operatively associated with the energized line 96 and simultaneously draw the common pole or wiper 98 toward terminal 100 connected to switch 86 and locking open switch 86, the circuit is not completed through the locking coil 60 and the coil remains inactive until the door is moved to its closed position.  
  The closing of door 44 permits the door control snap action switch 88 to move to its open position, thus breaking the circuit through that switch to the relay 22. However, the circuit through the relay is not broken since the cam operated switch 66 remains closed and the switching connection 102 of the security switch unit 18 permits current flow through line 96 to coil of the holding or arming relay 22. As mentioned, the snap action door control switch 86 controlling energization of coil 60 of the locking solenoid is in its open position when the door is open and the closing of the door will move the switch 86 to a closed position and allow the current to pass therethrough to energize the coil 60. This in turn will cause the bolt 48 to move to its locked position and, as the bolt moves, the cam 62 secured thereto operates on the leaf 64 of switch 66 to drive the snap action switch 66 to its open position, thus breaking the return for the holding circuit on the relay coil 90. This action allows the relay 22 to return to its original position, as illustrated, turning off the automatic arming or holding relay 22. As can be seen, the dual control switches 14 and 16 are effective to unlock the door in the remote secure area. The opening of the door activates the automatic holding circuit for the locking mechanism which automatically locks the door as soon as the door returns to its closed position.  
  .Within the locked secure area 12 there is provided a manually operated, momentary, normally opened push switch 104 which completes the circuit between the coil 56 of the unlocking solenoid and the closed switching connection 102 of the security unit 18. Thus a person within the security area 12 need merely push the switch 104 to its closed position to activate the unlocking coil 56 and effect unlocking of the access door. The release of the momentary, push switch 104, of course, breaks the circuit, thus placing the system in the same unlocked condition as is accomplished by means the dual controls 14 and 16. Thus, the bolt 48 is moved to the left, as viewed in FIG. 2, to its unlocked position and the cam 62 releases the snap action switch 66 for movement toward a closed circuit position. As soon as the door is open, the snap action switch 88 controlling .the relay 22 is moved to its closed position to activate the automatic arming circuit in identically the same manner as described hereinbefore. Thus, as will be appreciated, the system of the present invention provides ready unlocking from within the secure area coupled with automatic locking of the secure area each time the door or closure thereto is moved to its closed position regardless of whether the door is unlocked from the inside or the outside of the secure area.  
  It is an advantageous feature of the present invention that the security system described herein includes a se curity switch unit 18 which, in the case of a motel, might be considered to be a night latch to permit a person within the secure area to prevent access to the area without his permission. The security disconnect 18 takes the form of a DPDT switch that is controlled from the interior of the secure area and comprised of switching connections 102 and 106. As mentioned hereinbefore, the switching connection 102 of the unit 18 permits unlocking of the door from the interior of the secure area and also provides for a closed circuit condition through the automatic arming or holding relay 22 of the automatic locking mechanism. Similarly, switching connection 106 completes the circuit between the controls 14 and 16 and the unlocking coil 56. However, assoon as a person within the interior of the secure area 12 manually actuates the security unit 18 so as to move the switches 102 and 106 out of their illustrated positions, the switch 102 moves to an open circuit position and the switch 106 closes the circuit between the control switches 14 and 16 and the alarm system 28. Thus, if a person with a stolen or duplicate key attempts to enter the secure area after the night latch has been actuated, the circuit to the alarm system will be closed by the key, thus activating the alarm system. Similarly the person within the secure area cannot actuate the unlocking coil 56 by means push button switch 104 without first deactivating the security switch unit 18 by moving switches 102 and 106 to the positions illustrated in FIG. 3.  
  When it is necessary to service the remote secure area, the attendant manning the central control area can notify the service organization, such as the maid service of a motel, that service is required within a specific area. This is accomplished by simply closing the DPDT switches 110 and 112 located at the central control area 10. This will activate an appropriate signal such as the indicator light 114. The attendant at the desk thereby also energizes the line to a manual probe switch 116 located at the secure area. Actuation of probe switch 116 bypasses the dual key control to complete the circuit to the security switch unit 18 and effect energization of the coil 56 of the unlocking solenoid. As will be appreciated, the operation of the service bypass can be rendered ineffective by a person within the secure area by simply opening the circuit at the security unit 18. For example, a person within a motel room could open the security switch unit 18 so as to prevent a maid from entering the room while the person within the room was still sleeping. The switching of the security unit to the open condition not only completes the circuit to the alarm 28 but also gives the person within the restricted area a dead bolt protection.  
  If a person within a secure area becomes incapacitated or if other emergency conditions arise, the attendant at the central control area would be capable of unlocking the door to the secure area by means of the emergency bypass switch 32. This is provided by a direct line to the coil 56 of the unlocking solenoid that is controlled solely by a momentary, normally open push button type switch 32 located within the central control area 10. This switch is preferably mounted within a locked cabinet within the control area and is used only under appropriate emergency conditions.  
  As mentioned, the bolt 48 used to lock the secure area may be provided with a protruding knob 46 that is accessible from inside the secure area to provide a manual bypass of the electrically operated system in the event of total power failure. In this way, a person within the secure area can unlock the door and the door can be unlocked or locked as needed by persons remaining within the secure area.  
  As will be appreciated by person skilled in the art, various modifications, adaptations and variations of the foregoing specific disclosure can be made without departing from the teachings of the present invention.  
 1 claim:  
  1. An electrical key-actuated security locking system comprising a control area; a remote secure area including an access closure movable between open and closed positions; a power source; a locking member associated with said closure and movable between a locked condition and an unlocked condition to permit movement of said access closure into and out of its closed position; locking and unlocking circuits including electrically actuated means for driving said member between its locked and unlocked conditions; said unlocking circuit including a first switching means at said control area connected to said power source and a second switching means in series with and remotely located from said first switching means, said second switching means being key-actuated and electrically connected to said electrically actuated means for driving said locking member to its unlocked condition upon closing of said first and second switching means; holding circuit means operatively associated with said locking circuit and activated in response to movement of said locking member to said unlocked condition and movement of said access closure to an open position to condition said electrically actuated means for driving the locking member to its locked condition upon return of said access closure to said closed position; and a security switch controlling the operation of said holding circuit means and being adapted to interrupt both said locking and unlocking circuits to secure said secure area by preventing key-actuated operation of said locking member, said security switch being operatively controlled from the interior of said secure area.  
  2. The system of claim 1 wherein said first switching means is key-actuated and said system includes an alarm operatively connected to said first and second key-actuated switching means by said security switch upon interruption of said unlocking circuit by actuation of said security switch from within said secure area.  
  3. The. system of claim 1 wherein said first switching means is key-actuated and said locking and unlocking circuits include separate locking and unlocking means for driving said locking member.  
  4. The system of claim 1 wherein the unlocking circuitincludes an unlocking coil and the electrically actuated means includes a plunger operable by the coil and drivably connected to the locking member, said unlocking circuit including a closure-responsive switch for interrupting said circuit upon movement of said closure out of its closed position.  
  5. The system of claim I wherein said holding and locking circuits include a cam-operated switch responsive to the movement of the locking member into and out of its locked condition for completing and interrupting said holding and locking circuits.  
  6. The system of claim 5 wherein said locking circuit includes a fisst closure-responsive switch operative upon movement of the closure out of its closed position for activating the holding circuit and a second closureresponsive switch operative upon movement of said closure into its closed position for activating the locking circuit for driving the locking member to its locked condition.  
  7. The system of claim 1 including an alarm adapted to be operatively connected to said first and second switching means upon interruption of the circuits by said security switch.  
 8. The system of claim I wherein the unlocking circuit includes a bypass at the control area connected to the means for driving the locking member to its unlocked condition to permit service access to the remote secure area, said security switch being capable of interrupting said unlocking circuit to prevent service access.  
  9. The system of claim 1 wherein the unlocking circuit includes a bypass operatively controlled from the interior of the secure area for driving the locking member to its unlocked condition to permit access to the remote secure area, said security switch being capable of interrupting said unlocking circuit to prevent said bypass controlled access.  
  10. The system of claim 1 including an emergency bypass controlled at the control area and directly connecting the power source with unlocking circuit beyond the security switch to defeat interruption by said security switch.  
  11. The system of claim 1 wherein said locking member includes means controlled from within said secure area for manually moving said locking member into and out of its locked condition.  
  12. The system of claim 1 wherein the locking and unlocking circuits include locking and unlocking solenoid coils and the electrically actuated means includes aplunger operable by the coils and drivably connected to the locking member, said unlocking circuit including a closure responsive switch for interrupting said circuit upon movement of said closure out of its closed position. said holding circuit including a relay operable for energizing said locking coil upon return of the closure to its closed position, and an alarm operatively connected to said first and second switching means upon interruption of said unlocking circuit by said security switch.