Security System And Lock Therefor

Abstract

A security system includes a lock for securing a door and an alarm to signal when the door is ajar. The lock has a latch bolt which projects into a keeper in the door frame and an operating mechanism for retracting the latch bolt. A key operated locking device when locked prevents the operating mechanism from retracting the latch bolt. When the key operated locking device is unlocked with the proper key to enable the latch bolt to be retracted, a switch closes to deactivate the alarm long enough to enable one to open the door, pass through the door opening, and then close the door.

Description

BACKGROUND OF THE INVENTION

This invention relates in general to security systems and more particularly to a security system having an alarm to signal security breaks at a locked door and means for deactivating the alarm when authorized personnel unlock the door.

The operators of many large office buildings, warehouses, and the like employ security personnel to patrol the buildings and prevent unauthorized entry. This is quite expensive, and by reason of this fact, many buildings of recent construction have electical security systems for maintaining surveillance over doors at critical locations therein and for controlling the locks which secure those doors. These systems are usually provided with key operated switches in the door jambs to deactivate the alarm system for a short interval of time so that authorized personnel can pass through the doors without triggering the alarm. Usually the switches activate a time delay which deactivates the alarm for about 20 seconds --time enough for the individual to unlock the door, pass through the door opening, and then close the door again. These systems are quite bothersome to those who use them, since two key locks must be operated to pass through each door.

SUMMARY OF THE INVENTION

One of the principal objects of the present invention is to provide a security system which enables authorized personnel to pass through doors without setting off an alarm and with minimum inconvenience. A further object is to provide a security system of the type stated which utilizes locks of current construction having easily performed modifications. An additional object is to provide a lock suitable for use in a security system of the type stated. These and other objects and advantages will become apparent hereinafter.

The present invention is embodied in a security system having an alarm and a lock for securing a door. The lock may be released by release means which further operates means for deactivating the alarm so that authorized personnel can pass through the door without triggering the alarm. The invention also resides in the lock itself. The invention also consists in the parts and in the arrangements and combinations of parts hereinafter described and claimed.

DESCRIPTION OF THE DRAWINGS

In the accompanying drawings which form part of the specification and wherein like numerals and letters refer to like parts wherever they occur.

FIG. 1 is a perspective view of a door connected with an alarm and having a lock constructed in accordance with and embodying the present invention;

FIG. 2 is a perspective view of a hinge used on the door illustrated in FIG. 1;

FIG. 3 is an exploded perspective view of one of the locks forming part of the present invention;

FIG. 4 is an elevational view, partially broken away, of the latch assembly for the lock illustrated in FIG. 3;

FIG. 5 is a sectional view in elevation showing another lock forming part of the present invention; and

FIG. 6 is an electrical schematic view showing the lock of FIG. 5 connected with an alarm.

DETAILED DESCRIPTION

Referring now to the drawings (FIG. 1), a secrrity system has a door D which is hung on and swings away from a door frame 2 having a strike jamb 4 and a hinge jamb 6. The door D is actually hung on hinges 8 and 10 which are attached to the hinge jamb 6. The hinges 8 are conventional full mortise hinges, while the hinge 10, besides being a full mortise hinge, is also so-called contact hinge which completes several electrical circuits when closed. The door D is provided with a lock L, while the strike jamb 4 is fitted with an apertured strike or keeper 12 which the lock L engages and thereby prevents opening of the door D.

The contact hinge 10 (FIG. 2) is disclosed in U.S. Pat. No. 3,659,063, and for purposes of this discussion it is sufficient to note that the hinge 10, like the conventional hinges 8, has leaves 14 and 16, but that the leaf 14 has four contacts 18a, 18b, 18c, and 18d, while the other leaf 16 has four spring loaded contactors 20a, 20b, 20c and 20d which align with and engage the contacts 18a, 18b, 18c and 18d, respectively, when the hinge 10 is closed. However, when the hinge 10 opens, the contacts 18 separate from their respective contactors 20. The contacts 18 and contactors 20 are set in dielectric bushings 22 which insulate them from the hinge leaves 14 and 16 and from one another. Thus, the hinge 10 when closed can complete four different electrical paths or lines.

The contractors 20a, b of the contact hinge 10 are connected with an alarm A such that alarm A will be actuated when the contactors 20a, b are separated from their respective contacts 18a, b, thereby breaking an electrical circuit through the contacts 18a, b and contactors 20a, b. The alarm A is located in a security office or at some other place remote from the door D. During normal business hours the alarm A may be deactivated, but after business hours it is set to maintain surveillance over the door D. Thus, when the door D is opened, the alarm A will be actuated, provided the alarm A is set to operate.

The lock L is a standard unit-type lock which is modified such that when it is unlocked a switch is activated to temporarily inactivate the alarm A. The lock L includes (FIG. 3) a latch assembly 30 and a pair of knob assemblies 32 and 34.

The latch assembly 32 (FIGS. 3 and 4) is located in the door D directly opposite from the keeper 12 and has a face plate 36 which is set into the edge of the door D such that its outside face is flush with the edge surface of the door D. Fastened to the face plate 36 and projected into the door D therefrom is a bolt housing 38 which houses a spring loaded latch bolt 40. When the door D is closed, the latch bolt 40 aligns with and projects into the apertured keeper 12 or the strike jamb 4, and the spring loading is such that the latch bolt 40 is urged outwardly beyond the face plate 38. Thus, unless retracted, the latch bolt 40 will prevent the door D from opening. Projected in the opposite direction from the housing 38 are a pair of guide plates 42 joined at their ends by spaced apart connecting portions 44 (FIG. 4). Between the guide plates 42 is an actuating stem 46 which is somewhat shorter than the guide plates 42 and projects into the bolt housing 38 where it interlocks with latch bolt 40. The connection is such that the actuating stem 46, when moved toward the connecting portions 44 at the ends of the guide plates 42, will draw the latch bolt 40 into the housing 38 a sufficient distance to enable the latch bolt 40 to be withdrawn completely from the keeper 12. Nevertheless, the connection permits independent movement of the latch bolt 40 with respect to the actuating stem 46 so that the bolt 40 can be depressed into the housing 38 upon striking the keeper 12, without causing the actuating stem 46 to move toward the connecting portions 44 on the guide plates 42. The actuating stem 46 is provided with a noncircular aperture 48 having generally vertical margins at its upper and lower ends.

Attached to the ends of the guide plates 42 located remote from the bolt housing 38 is a switch housing 50 (FIGS. 3 and 4) containing a switch 52 which has an operating blade 54 located in the path of the actuating stem 46. The blade 54 is positioned such that when the activating stem 46 is moved far enough to retract the latch bolt 40 from the keeper 12, the actuating stem 46 will also engage the blade 54 and cause it to close the switch 52. The switch 52 is connected to the alarm A through the contacts 18c and 18d and the corresponding contactors 20c and 20d of the contact hinge 10 (FIG. 2). When closed, the switch 52 triggers a time delay in the alarm A, and this time delay deactivates the alarm A for a short interval of time, such as 20 seconds. Thus, during this interval the door D may be opened without setting off the alarm A.

The knob assembly 32 (FIG. 3) includes a circular mounting plate 60 which is fastened firmly against one face of the door D. The plate 60 carries a handle or knob 62 which is capable of rotating in the plate 60, and the knob 62 has an operating spindle 64 secured firmly to it. The spindle 64 projects through the noncircular aperture 48 in the actuating stem 46 and has a pair of longitudinally extending edges positioned adjacent to the upper and lower vertical margins of the aperture 48. Thus, when the spindle 64 is rotated in either direction by turning the knob 62, the actuating stem 46 is driven toward the hinge jamb 6 and the latch bolt 40 is withdrawn from the keeper 12. The knob 62 and its spindle 64 coupled with the actuating stem 46 constitute operating means for retracting the latch bolt 40.

The knob 62 contains a locking mechanism 66 (FIG. 3) which is operated by a key 68 and may be moved by key 68 between locked and unlocked positions. When the lock mechanism 66 is in its locked position, it interlocks with the mounting plate 60 and prevents the knob 62 from rotating. When the lock mechanism 66 is in the unlocked position, the knob 62 is free to rotate in the mounting plate 60 and thereby turn the spindle 64.

The knob assembly 34 (FIG. 3) also includes a mounting plate 70 which is fastened against the opposite face of the door D. The mounting plate 70 carries a handle or knob 72 which is capable of rotating relative to the mounting plate 70. The inner end of the knob 72 has a socket which receives the end of the spindle 64 projecting from the other knob 62, the fit being such that the spindle 64 and knob 72 will rotate together so that when one is turned, the other is also. The knob 72 contains an operating disk 74 which is connected with the lock mechanism 66 in the knob assembly 32 and when turned will move the lock mechanism 66 between its locked and unlocked positions.

Aside from the switch housing 50, and the switch 52 housed therein, the lock L is a conventional unit-type lock, with the one illustrated being currently sold under the trademark KWIKSET.

OPERATION

When security precautions are in effect, the alarm A is set such that when the alarm circuit through the contacts 18a, b of the contact hinge 10 is broken, the alarm A will be activated and will thereby signal a security violation at the door D. The alarm circuit is, of course, broken by opening the door D for then the contactors 20a, b will separate from their respective contacts 18a, b. Consequently, anyone opening the door D when security precautions are in effect will set off the alarm A, provided the alarm A is not temporarily deactivated.

Authorized personnel, that is anyone possessing a key 68 which fits the lock mechanism 66, may pass through the door D without activating the alarm A. In particular, when the proper key 68 is inserted into the lock mechanism 66 and turned to move the lock mechanism 66 to its unlocked position, the knob 62 may then be turned to withdraw the latch bolt 40 from the keeper 12 and thereby release the door D from the strike jamb 4. Before the latch bolt 40 is completely withdrawn from the keeper 12, that end of the activating stem 46 located remote from the latch bolt 40 will engage the operating blade 54 of the switch 52 and close the switch 52. Since the switch 52 is connected to the alarm A through the engaged contacts 18c, d and contactors 20c, d of the contact hinge, the completion of the deactivating circuit results in a signal at the alarm A, and this signal deactivates the alarm A for a prescribed duration of time. Usually the alarm A is deactivated just long enough for a person to open the door D, pass through the door opening, and then close the door D.

Consequently, authorized personnel can open the door D without any inconvenience whatsoever, even when the alarm A is set to detect security violations.

MODIFICATION The present invention may also be utilized with more sophisticated security systems such as the one disclosed in U.S. patent application, Ser. No. 296,561, filed Oct. 11, 1972 by Francis C. Peterson. In that security system a standard mortise lock provided with an auxiliary latch is modified such that it may be monitored and operated from a remote location. However, once the alarm system is set, the door secured by the lock cannot be opened even by authorized personnel, without setting off the alarm. By incorporating the principal of the present invention into the lock, the foregoing problem is overcome. Sometimes separate key operated switches are provided in these systems for deactivating the alarm long enough to permit passage through the door opening.

In the modified security system (FIGS. 5 and 6) the door D is provided with a mortise lock M having a case 80 and a face plate 82 across the front of the case 80. Projecting from the face plate 82 for entry into the keeper 12 on the strike jamb 4 is a spring loaded latch bolt 84 which moves between retracted and extended positions, but is urged toward its extended position by a spring 85. The face plate 82 also has an auxiliary latch 86 projecting from it, and the auxiliary latch 86 controls the position of a locking lever 88. The auxiliary latch 86 is urged to an outwardly projecting position and assumes this position when the door D is open. In that position, the auxiliary latch 86 permits the locking lever 88 to rise above the path of the latch bolt 84 so that the latch bolt 84 can be retracted. However, when the door D is closed, the auxiliary latch bears against and is depressed by the face of the keeper 12, and when so depressed allows the locking lever 88 to fall behind the latch bolt 84. Consequently, the latch bolt 84 cannot be retracted when the auxiliary latch 86 is depressed. This prevents someone from slipping a thin object such as a plastic credit card between the face plate 82 and the keeper 12 for the purpose of forcing the latch bolt 84 to its retracted position.

The locking lever 88 pivots about a pin 90 located near the rear of the case 80 and is further provided with an actuating arm 92 which projects through the back wall of the case 80 and into a switch housing 94 fastened to that back wall. The housing 94 carries a switch 96 having an operating blade 98 which is engaged by the actuating arm 92 of the locking lever 88. As the locking lever 88 moves between its upper and lower positions, the actuating arm 92 also moves and operates the switch 96, causing it to open and close. Thus, the switch 96 maintains surveillance over the position of the locking lever 88, and the position of the locking lever 88 determines the security of the lock M.

The latch bolt 84 is retracted by either one of two levers 100, 102, and these levers, in order to move the latch bolt 84, lift the locking lever 88. The lever 100 is operated by a pair of handles or knobs (not shown) which are exposed on each face of the door D and are connected by means of a split spindle 106. Actually the spindle 106 extends through hubs 108, and when these hubs 108 are turned by the spindle 106, they cam the lever 100 such that it retracts the latch bolt 84. The other lever 102 is operated by a cylinder-type locking mechanism 110 which is threaded into the case 80. The locking mechanism 110 has a tumbler cylinder 112 in it, and this cylinder is normally prevented from rotating by the lock tumblers. However, when the key is inserted into the tumbler cylinder 112, it frees the cylinder 112 for rotation. On its back end the tumbler cylinder 112 is fitted with an actuating tab 114 which engages the operating lever 102 and moves that lever such that it retracts the latch bolt 84. Thus, the latch bolt 84 may be retracted by turning the lock cylinder 110 or the door knobs. The tab 114 coupled with the lever 102 constitute operating means for retracting the latch bolt 84.

The door knob on the same side of the case 80 as the lock cylinder 110 may be locked against rotation by a solenoid 120 which is mounted on the switch housing 94 and has its armature 121 connected to a linkage 122 which extends into the case 80. The actual connection is effected by means of a connecting pin 123. The linkage 122 is in turn connected to a locking dog 124 which shifts toward and away from the hubs 108. The hub 108 which is operated by the knob 104 on the same side of the lock M as the lock cylinder 110 has a groove 125 for receiving the locking dog 124. When the solenoid 120 is energized and its armature 121 retracted, the locking dog 124 will be urged into the groove 125 in the hub 108 and hence will prevent the knob associated with that hub from rotating. On the other hand, when the solenoid 120 is not energized, a spring therein will force the armature 121 outwardly, and likewise, the locking dog 124 will move away from the hub 108 so as to free the hub 108 and its knob 104 for rotation. The electrical current for energizing the solenoid 120 is derived from a remote source and passes through the contacts 18a, d and contactors 20a, d of the contact hinge 10.

The switch housing 90 also contains a switch 126 provided with an operating blade 128 which lies in the path of the connecting pin 123 for the armature 121 of the solenoid 120. The switch 126 is positioned such that it is opened and closed by the pin 123 the armature 121 moves between extended and retracted positions.

The switch 96 is closed when the locking lever 88 is in its lower position, that is when it blocks the latch bolt 84 and is open when the locking lever 88 is in its upper position. The switch 126, on the other hand, is closed when the armature 121 for the solenoid 120 is retracted, in which case the knob 104 is prevented from rotating, and is open when the armature 121 is extended. Moreover, the two switches 96 and 126 are connected in series and are further connected to the alarm A through the contacts 18c, d and contactors 20c, d of the contact hinge 10 (FIG.6). Should the circuit through the switches 96 and 126 be broken, the alarm A will sound indicating that a security violation has occurred at the door D. The following conditions will result in an open circuit and hence an alarm signal:

1. The door D is ajar -- circuit broken at contacts 18c, d and contactors 20c, d.

2. Locking dog 124 withdrawn from the groove 125 in the hub 108 so that rotation knobs 104 will withdraw latch bolt 84-circuit broken at switch 126.

3. Locking lever 88 in upper position in which case it does not block latch bolt 84-circuit broken at switch 96. Mounted within the case 80 adjacent to operated by locking mechanism 110 is still another switch 130 having an operating blade 132 which lies in the path of the actuating tab 114. Moreover, the operating blade 132 is positioned to that side of the operating lever 102 which is engaged by the actuating tab 114 in order to retract the latch bolt 84. Thus, as the tab 114 rotates toward the operating lever 102 it will close the switch 130 and thereafter will engage the operating lever 102 and shift that lever such that it lifts the locking lever 88 and retracts the latch bolt 84.

The switch 130 is connected to the alarm A through the contacts 18b, d and contactors 20b, d of the contact hinge, and when closed triggers a time delay which deactivates the alarm A for a short duration, that is long enough to enable one to open the door D, pass through the door opening, and then close the door D.

This invention is intended to cover all changes and modifications of the example of the invention herein chosen for purposes of the disclosure which do not constitute departures from the spirit and scope of the invention.

Claims

What is claimed is:

1. In a security system including a door which opens from a door frame having a strike thereon, an alarm connected with the door for signalling when the door is open, and a lock for securing the door in a closed position, the lock including a latch blot which is normally urged beyond the edge of the door for engagement with the door frame to secure the door in a closed position, and movable operating means engageable with the latch bolt to retract the latch bolt when the operating means is moved, the latch bolt being retractable independently of the operating means to enable the latch bolt to retract upon engaging the strike of the door frame without moving the operating means; the improvement comprising switch means connected to the alarm for deactivating the alarm for a limited time when said switch means is operated, the switch means being operatiedby the operating means when the operating means is moved such that it retracts the latch bolt.

2. The structure according to claim 1 wherein the operating means includes a key-operated locking device.

3. The structure according to claim 2 and further characterized by a hinge having one leaf fastened to the door frame, and another leaf fastened to the door, and contact means carried by the leaves for completing an electrical circuit between the switch and the alarm when the door is closed.

4. The structure according to claim 1 wherein the operating means further includes a stem connected with the latch bolt and a handle engageable with the stem for retracting the latch bolt when the handle is turned, the switch being positioned in the path of the stem so that it is operated by the stem as the latch bolt is retracted.

5. The structure according to claim 4 wherein the operating means further includes a key operated locking mechanism for preventing rotation of the handle.

6. The structure according to claim 1 wherein the operating means includes a key operated tumbler cylinder having a tab which rotates as the cylinder is turned and retracts the latch bolt, the switch means being located in the path of the tab and being operated by the tab as the cylinder is turned.

7. The structure according to claim 1 wherein the operating means includes a handle which is exposed outside the door and when turned withdraws the latch bolt; and wherein a key operated locking device is in the handle and prevents the handle from rotating when in a locked condition.

8. The structure according to claim 7 wherein the operating means further includes a stem and the handle is connected with the stem such that when the handle is turned the stem is moved and the latch blot is retracted; and wherein the switch is engaged and operated by the stem.

9. The structure according to claim 1 wherein the key operated locking device includes a lock cylinder secured to the case and having a rotatable tumbler cylinder which rotates in the lock cylinder and receives the key; and wherein the operating means includes a tab which is fastened to the tumbler cylinder and rotates with the tumbler cylinder, the switch being in the path of tab and being operated by the tab as the tumbler cylinder rotates.

10. A security system for a door hinged to a door frame having a strike thereon, said security system comprising an alarm, a lock having a retractable latch bolt which is normally urged outwardly beyond the edge of the door to project into the strike and thereby secure the door, the latch bolt having a face which engages the strike as the door closes and causes the latch bolt to be retracted momentarily, a manually operated mechanism engageable with the latch bolt to retract the latch bolt, the latch bolt being retractable independently of the manually operated mechanism so that the latch bolt does not move the manually operated mechanism when so retracted; means for actuating the alarm when the door is opened, and switch means actuated by the manually operated mechanism and connected to the alarm for deactivating the alarm for a limited time when the latch bolt is retracted by the manually operated means.

11. A security system according to claim 10 and further characterized by a hinge for supporting the door on the door frame having contacts and contactors thereon, the switch means being connected to the alarm through contacts and contactors of the hinge.

12. A security system according to claim 11 wherein at least some of the contacts and contactors of the hinge break when the door is opened and the breaking of said contacts and contactors actuates the alarm if the alarm has not been deactivated by the switch means.

13. A security system according to claim 10 wherein the operating mechanism includes a key operated lock having a rotatable cylinder which is rotated by a key inserted therein, and a tab on the cylinder, the switch means being in the path of the tab so that the tab operates the switch means as the tab is rotated by the cylinder to retract the latch bolt.

14. A security system according to claim 10 wherein the operating mechanism includes a stem projected beyond the latch bolt in the direction the latch bolt moves, the stem being connected with the latch bolt such that when the stem is moved away from the edge of the door from which the latch bolt projects, the latch bolt is retracted and such that the latch bolt can be retracted without moving the stem, a spindle projected through the stem and having edges which contact the stem and move the stem as the spindle is turned, and at least one handle connected firmly to the stem and exposed at the exterior of the door for turning the stem.

15. A security system according to claim 10 and further comprising a second manually operated mechanism engageable with the latch bolt to retract the latch bolt, the second manually operated mechanism including a handle exposed at the exterior of the door; a dogging mechanism engageable with the second manually operated mechanism to dog the second mechanism and prevent it from retracting the latch bolt, and another switch means operable by the dogging mechanism for monitoring the position of the dogging mechanism.

16. A security system according to claim 10 and further comprising a locking lever movable between a blocking position wherein it prevents retraction of the latch bolt and a release position wherein it permits the latch bolt to retract, an auxiliary latch which is located opposite the strike and depressed by the strike when the door is closed, but when the door is open extends beyond the strike, the auxiliary latch when extended holding the locking lever in its release position and when depressed allowing the locking lever to move to its blocking position, and additional switch means operated by the locking lever for monitoring the position thereof.