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Publication numberUS3745551 A
Publication typeGrant
Publication dateJul 10, 1973
Filing dateAug 12, 1970
Priority dateAug 12, 1970
Publication numberUS 3745551 A, US 3745551A, US-A-3745551, US3745551 A, US3745551A
InventorsSmith L
Original AssigneeSmith L
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Alarm apparatus and method
US 3745551 A
Abstract  available in
Images(3)
Previous page
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Claims  available in
Description  (OCR text may contain errors)

United States Patent 1 1 Smith 1 1 3,745,551 1 1 July 10, 1973 ALARM APPARATUS AND METHOD [54] 3,537,094 10/1970 Hawkins et a1. 340/276 X 3,286,250 11/1966 Teitelbaum 340/276 [761 Invent mug! l 3400 Carly" 3,074,049 l/1963 Saliba 61 al. 340/276 x Spring Road, Falls Church, 3,544,987 12/1970 McMann, Jr. et al. 340/276 x [22] Filed: Aug. 12, 1970 Primary ExaminerJohn W. Caldwell [21] Appl' 631ll Assistant Examiner-Scott F. Partridge Attorneywilfred G. Caldwell [52] US. (31. 340/276, 340/274 [51] Int. Cl. G08b 13/08 58 Field 6: Search 340/274, 276, 221, [571 ABSTRACT 63, 149 R, A portable or fixed servicealarm device that clamps 147 R onto a door, wherein; when occupant is absent, the violated alarm sounds each time the door is opened for 60 1 References Cited seconds and then shuts off; provides an unobvious indi- UNlTED STATES PATENTS cation of a past violation from the outside of the door; 3,234,532 2/1966 Rogers 340/213 when p is Present, the Sound cannot be quieted 3,634,846 l/ 1972 Fogiel 340/274 without a key; at all times, a doorbell is'present, but not 3,581,300 5/1971 Eloranta 340/2131 attached, at the outside of the door for the convenience 3,530,455 9/1970 Ressler 340/274 of anyone wishing to gain admittance. 3,281,810 10/1966 Thornberg et a1. 340/213 3,550,121 12/1970 Porter, Sr. IMO/213.1 X 16 Claims, S'Drawing Figures c h 1 f NONLINEAR LATCHING EJE E CONDUCTOR CONDUCTOR coNDucToR GENERATOR TURN ON ['15 1 '1 i'T xo SHEET 2 U? 3 INVENTOR= LY LE DOUGLAS SMITH PATENTEDJWL 1 0 I975 SHEET 3 UP 3 FIGURE 3 INVENTOR LYLE DOUGLAS SMITH 1 ALARM APPARATUS AND METHOD BACKGROUND OF THE INVENTION Presently known alarm systems have little utility for tenants of apartment dwellings. The use of the conventional alarm device is usually prohibited by the apartment management because of the impediment'to maintenance personnel and the illegal and disturbing sound level duringtesting and accidental or false triggering of the alarm. If permission is given, spare keys and instructions for disabling the alarm must be given to the apartment management, thus, lessening security because of the possibility of lost keys and dishonest personnel.

Important objectives of the invention are to provide:

1. A device primarily, but not exclusively, designed for tenants of apartment dwellings with features that overcome restrictions imposed on tenants by apartment managements, civil statutes pertaining to disturbing the peace, and consideration for ones neighbors.

2. A device primarily designed to protect personnel, and, secondarily property. 3. A self-contained device capable of being installed by any person,regardless of mechnical aptitude, in about seconds and incorporating battery replacement with very little effort.

4. A device in which the operating capability and battery condition are automatically tested and reported when the normal operating sequence is performed.

5. A device that cannot be inadvertently operated in a mode contrary to restrictions imposed by management, civil statute and good taste.

6. A device economically practical because of low initial cost, low operating cost, transferability to new lodgings, and being of a quality appliance nature capable of many years of trouble-free and reliable service.

7. A device with the three security modes of ATTENDED ALARM (tenant remaining in apartment);

UNATTENDED ALARM (tenant away from apartment);

MEMORY ALARM (a silent recorder of a violation;

and a security related, but convenience oriented, mode of:

DOORBELL (memory alarm interrogating function,

as well as being a convenient doorbell).

SUMMARY OF THE INVENTION The invention shifts emphasis from protecting property to protecting tenants from harm by indicating that the apartment has been violated and the intruder may still be present, or is being violated and appropriate action must be taken.

This new philosophy enables the design of a device that eliminates the disadvantages of the conventional alarm. An explanation of the operation of the invention will make the advantages of the invention clear. For simplification, it is assumed that the apartment is inaccessible except through the door. If the tenant is in his apartment and wishes protection from a sneak intruder, he turns the key operated number 1 switch of the invention to attended mode and removes the key to any inconspicuous location. If there is a knock on the door, the door can be opened without triggering the alarm by holding a push button depressed during the time the door is opened. If the door is opened without the push button being depressed, a penetrating, but not illegally loud, sound is emitted and cannot be quieted without the key operated switch being switched to memory mode. Most intruders should make a rapid departure; if not, the tenant is at least forewarned and can take appropriate action.

To prevent triggering of the attended mode by maintenance or management personnel when the tenant is away, the invention (switched .to attended mode) will not allow the tenant to leave without triggering. However, after triggering, the key operated switch is immediately switched to memory mode. The tenant has unavoidably tested the invention and battery condition, and leaves taking the key with him.

Upon returning, the tenant can tell by pushing his doorbell (attached to or an integral part of the alarm device) if the door has been opened, in his absence. If he hears the alarm sound for as long as he holds the button depressed, it indicates that the memory is still in operation and he can be certain that the door hasnot been opened. If he hears the alarm sound only momentarily and fades away (bell-like) with each depression of the button, he should not proceed without checking with the apartment manager to find whether maintenance personnel have been, or are, in his apartment, and then take appropriate action if needed. Assuming the alarm sound is not heard, the tenant opens the door and the device automatically and silently turns off enabling the doorbell characteristics to return.

When the tenant is leaving, an additional action may.

be taken, in another embodiment, to protect his property in his absence. After turning the key operated number 1 switch to memory, thenumber 2 key operated switch is set to the unattended mode position (ON). Then the tenant leaves, closing the door behind him. From now on, whenever the door is opened, the alarm will sound for seconds and then will quiet and reset itself. Therefore, regardless of whether or not his doorbell indicates a violation, he himself will violate his alarm and will be required to use his key to turn off the 60 second alarm. The purpose of the 60 second alarm condition is to provoke an intruder into leaving immediately for obvious reasons when the door is first opened and still provide access to maintenance or management personnel without providing them with a key. The 60 seconds of annoyance will help maintenance and management personnel remember the incident later when the tenant asks them if someone is in or has been in his apartment. It is wise to inquire before entering, for if the doorbell indication shows that the door has been opened, an intruder (other than maintenance) could still be there.

It should now be apparent that the method and apparatus of thisinvention is applicable to other security locations, such as top-secret rooms or buildings, storage closets, filing cabinets, and the like.

With foregoing in mind, it is an object of the invention to provide a combination attended-memory alarm type indicator. Another object of the invention is the provision of such an apparatus which automatically signals'if left in the attended mode, thereby serving to indicate its alarm capabilities, as well as to alert the'user to shift the key to the memory position. v

A further object of the invention is the-provision of a method primarily for protecting a person, as contrasted with prior art methods for protecting only personal property. A further object of the method is to insure that the user operates the device properly,-and is aware of its operational state.

Yet another object of the invention is to provide a circuit absolutely capable of minimum power drain, although maintaining the apparatus continuously in an operational state in one of the various modes. A feature of the invention resides in the fact that the circuit is switched off from the memory mode when the door is opened and at the users option may be programmed to the attended mode. other features include the doorbell.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram to illustrate the principles of the invention, and broadly depicts the various circuits and switching techniques employed,

FIG. 2 shows the complete electrical diagram of the invention to carry out the features of the various embodiments thereof, and

FIG. 3 shows the mechanical relationships between the alarm housing, doorbell housing, adjustable bracket, doorframe and door.

The method of the invention is most easily understood if the objectives and the abbreviated circuit of FIG. 1 are described separately. The Sound Emitter A cannot sound unless one of the three paths to ground are conducting. The first path is through one half of the Double-Pole Double-Throw (DPDT) Key Operated Switch B and then through the Latching Conductor C. The Latching Conductor C is only latched ON when one half of the DPDT Key Operated Switch D is switched to the position shown and the Normally Closed Door Actuating Switch E is allowed to close by the opening of the-door being protected.

It can now be seen that a person on the inside of the door will be warned instantly if his door is opened, unless he holds depressed the Normally Closed Authorized Admittance Push Button Switch F, used to answer a knock at the door while still having the device in a ready condition.

Once the Latching Conductor C is turned on, it latches and cannot be unlatched unless the one half of the DPDT Key Operated Switch D is switched to the opposite position, and the door closed, and once again opened, causing a single pulse from the Pulse Generator G to unlatch the Latching Conductor C.

It can now be seen that if the person on the inside of the door opens his own door in order to leave, he is automatically latching the Latching Conductor C and causing Sound Emitter A to sound; however, with his key, he switches one half of the DPDT Key Operated Switch (D) to the opposite position, readying the Latching Conductor C to accept a turn off pulse from Pulse Generator G the next time the door is opened. Simultaneously, the other half (B) of the DPDT Key Operated Switch disconnects the Sound Emitter A, except through Normally Open Doorbell Switch H, causing Sound Emitter A to go silent.

The person now leaves, closing the door behind him, and taking the key with him. When he returns, he pushes the normally Open Doorbell Switch H, and the path is now completed between Sound Emitter A and the still latched Latching Conductor C, causing sound for as long as he holds the Normally Open Doorbell Switch H closed. He now knows, by the continuous sound from Sound Emitter A, that the door has not been opened since his departure, because Latching Conductor C is still latched.

When he, thereafter, opens the door, Pulse Generator G generates a single pulse which automatically unlatches Latching Conductor C. Now, if someone pushes Normally Open Doorbell Switch H, the only path to ground for Sound Emitter A is through Nonlinear Conductor I, which allows full conduction momentarily but then tapers down to nothing. The effect is to now give Sound Emitter A a bell-like quality, distinctly different from its continuous sound, each time the Normally Open Doorbell Switch H is depressed.

A third path to ground may be provided for Sound Emitter A through the 60-Second Conductor J and the Single-Pole/Single-Throw (SPST) Key OPerated Switch K. The 60-Second Conductor J is turned ON by a single pulse from Pulse Generator G whose operation has already been described in application to the Latching Conductor C. However, the pulse turns the 60- Second Conductor J ON simultaneously with turning the Latching Conductor C OFF. It can now be seen that the last action the person takes before closing the door to leave is to switch the SPST Key Operated Switch K to the unattended mode position (ON). Now, in addition to the action of Latching Conductor C when the door is next opened, the 60-Second Conductor J turns ON Sound Emitter A for 60 seconds, then automatically turns off, and resets again for the next opening of the door. I

The functions and operations of the invention are accomplished by the following described circuit (FIG. 2). The total circuit of the invention is composed of various sub-circuit arrangements. The total circuit is most easily understood if the sub-circuits are described separately.

SOUND EMITTER ARRANGEMENT The circuit and transducer may be a single sealed plastic unit, sold under the trade name of Sonalert (reference no. 1 of list presented infra).

MODE SELECTOR ARRANGEMENT Key operated switch 2A and 2B (gauged together) selects either memory mode M position or attended alarm mode A position. These switches preferably comprise a single switch, but are considered separately tdsimplify the circuit description.

TURN ON ATTENDED ALARM ARRANGEMENT Key operated switch 28 provides continuity between the gate 3 of PUT 4 and ground (or battery negative) through the normally closed momentary contact push button switch 5 and the normally closed (when the door is opened) microswitch 6. In other words, switch 6 closes when the door is opened. PUT 4 turns ON because the anode 7 is more than 0.7 volts higher in potential than the gate 3. The path to ground for the current, causing sound emitter l to sound, is through diode 40 and PUT 4.

TURN OFF MEMORY ARRANGEMENT Resistors 8 and 9 provide charging current for capacitor 10 when PUT 4 is conducting, provided key operated switch 28 is in memory mode M position and normally closed momentary contact push button switch 5, or normally open (when the door is closed) microswitch 6 is in an open state. PUT 4 turns OFF when the charged capacitor 10 discharges to ground through normally closed momentary contact push button switch 5 and the normally closed (when the door is open) microswitch 6, thus, reverse biasing PUT 4 to accomplish turn OFF.

REMOTE ACTUATING ARRANGEMENT It will now be appreciated that the invention may be used as an indicating device for areas having more than a single access, each of which may require guarding. Thus, as many normally open switches as may be desired can be connected in parallel with the switch 5 and 6, as shown by switch 11, with takeoff leads l2 and 13 provided for additional switches. Thus, the windows and doors of a house, for example, could be used to turn off the memory whenever any access is violated. Similarly, if the device is in the attended alarm, the opening of any closure would latch on the sound emitter 1.

AUTHORIZED ADMITTANCE ARRANGEMENT MEMORY MAINTENANCE CURRENT ARRANGEMENT Resistor 14 provides current flow to PUT 4 when the' key operated switch 2A is switched from the sound emitter 1, position A, to the memory mode M position, therefore, preventing unavoidable turn OFF of PUT 4.

EXTRANEOUS NOISE SUPPRESSION ARRANGEMENT Capacitor 15 provides a short circuit for noise potentials between the anode 7 and the gate 3 that could randomly turn ON and OFF PUT 4.

DOORBELL ARRANGEMENT When the memory PUT 4 (programmable unijunction transistor) is turned OFF and normally open push button switch 16 (doorbell, if desired) is pushed, the path to ground for the current causing sound emitter l to sound is through diode 17, capacitor 18 and diode 19. The current rushes into capacitor 18 and then immediately tapers to zero (the effect is a bell-like sound). When normally open push button switch 16 is released, the voltage at gate 20 of PUT 23 falls to the negative side of the capacitor 18 through resistor 21. Capacitor 18 cannot discharge through resistor 21, being blocked by diode 17, therefore, a more than 0.7 volt positive potential exists between the anode 22 and gate 20 of PUT 23 causing it to conduct and discharge the stored current atthe positive plate of the capacitor through resistor 24 (used to protect PUT 23 from .excessive current flow) to the negative plate of the capacitor. The cycle is repeated each time normally opened push button switch 16 is activated.

DOORBELL ALTERNATIVE ARRANGEMENT To save expense, diode l7, resistor 21, PUT 23 and resistor 24 may be removed without changing the effect of the doorbell 16 the first time it is pushed; however, once the capacitor 18 is charged, sound emitter 1 goes silent, therefore, succeeding depressions of the doorbell button 16 would pass only the amount of current needed to offset leakage of capacitor 18. If a resistor with a value of no less than 220K ohm is paralleled with 60-SECOND TIMER ARRANGEMENT Sound emitter 1 will sound whenever SPST key operated switch 25 is switched to the unattended mode position (ON) and PUT 26 is latched on. To analyze how PUT 26 latches ON, assume that SPST key operated switch 25 is closed, DPDT key operated switch 28 is in memory mode M, normally closed push button switch 5 is closed and door actuated switch 6 is open (door closed). The anode 28 and the gate 27 of PUT 26 are at supply potential because of resistors 29 and 8, re-

spectively. If door actuated switch 6 is closed, there is a momentary low impedance path to ground for gate 27 of PUT 26 through capacitor 30. (Resistor 9 keeps capacitor 30 in a discharged low impedance condition, but does not provide adequate conduction to turn on PUT 26.) During this short period of time, gate 27 is more than 0.7 volt'negative in respect to anode 28, therefore, PUT 26 latches on. When PUT 26 is latched on, both anode 28 and gate 27 remain at near cathode 38 potential, therefore, the path to ground for the current causing sound emitter 1 to sound is through diode 31, PUT 26, SPST key operated switch 25 and diode 19. Because anode 28 of PUT 26 is now at the same potential as the cathode 43 of PUT 32, a voltage divider, consisting of resistor 33 and resistor 34, has come into effect between supply voltage and cathode 43 of PUT 32. The potential at the gate 35 of PUT 32 has fallen from supply potential to half supply potential. PUT 32 does not turn on, however, because capacitor 36 requires 60 seconds to charge through resistor 37'to a level bringing anode 39 over 0.7 volts positive in respect to the gate 35.

When the firing potential is reached, PUT 32 conducts causing the stored energy in capacitor 36 to re- .verse bias PUT 26, therefore, unlatching it. Because resistor 37 cannot supply adequate latching current for 60-SECOND TIMER ALTERNATIVE ARRANGEMENT To save expense, at a considerable loss of performance, the entire 60-second conductor portion may be removed and the operational characteristics changed to provide sound from sound emitter 1 whenever. the door is open (and only during the open period) provided SPST key operated switch 25 is switched to the unattended (ON) mode position. The actions of the doorbell circuit, memory circuit and attended alarm circuit, will not be affected by this change. The simplest way to explain the wiring changes is'to assume all of the 60-second conductor components are nonexistent except diode 31, resistor 9 and SPST key operated switch 25, and these three components are free of any circuit connection. The anode of diode 31 is connected to the moving contact of DPDT key operated switch 28. The cathode of diode 31 is connected to the junction of door actuated switch 6, remote switch line 12, and capacitor 10. The line that is now shorting diode 31 is removed. Capacitor 10 is then reconnected from the cathode of diode 31 to the anode of diode 31. Resistor 9 is connected from the anode of diode 31 to supply voltage. The SPST key operated switch 25 is connected between the cathode of diode 31 and the junction of sound emitter 1, push button switch 16 and position A of the DPDT key operated switch 2A. The modification of the circuit is now complete, position M of the DPDT key operated switch 28 need not be connected to any point.

SUBCIRCUIT INTERACTION SUPPRESSION ARRANGEMENT POWER SUPPLY ARRANGEMENT Battery 41 and battery 42 are in series to provide a total of 18 volts supply voltage.

The above described circuit achieves absolute minimal current drain, such that the batteries 41 and 42 may operate the circuit in the memory mode and unattended mode for periods substantially corresponding to their shelf life, and then the batteries may be replaced at minimal cost because they are conventional nine volt transistor radio batteries. Also, even if for some reason the circuitry is left inadvertently in the attended mode, it is calculated that the alarm would sound for several days. In order to achieve this unusual type of efficient operation, the following components have been suecessfully used:

Ref. No. Com- Manuof ponent facturer Stock No. Value Price FIG. 2

1 Sonalert Mallory S0628 5.50

2A and switch Smith I038 DPDT 2.73

28 k3 operated 4 P T GE Dl3Tl .79

5 switch Switch- 103 SPDT .60

pushbutton craft 6 Micro- Micro- 82- SPDT 2. l5

switch switch 2RW863-A2 8 resistor 10K l 0 9 resistor I OMEG l0 I0 capacitor Centralab CKI04 .l mfd .60

1 I much N.C.

14 resistor 220K l0 l5 capacitor lCgntra- CKI04 .l mfd .60

a [6 switch Switch- 103 SPDT .60

craft l7 diode GE lN9l4 .30

18 capacitor S rague Tel307 50 mfd .72

19 diode O E 1N9l4 .30

21 resistor 330K .10

23 PUT GE DI3TI .79

24 resistor 500 ohm I0 25 switch .Smith 1038 DPDT 2.73

It?! operated 26 P T GE D13T1 .79

29 resistor 33K I0 30 CEl02 .00! mfd .18

capacitor Centralab 8 31 diode GE lN9l4 .30 32 PUT GE Dl 3T2 1.58 33 resistor IMEG I 0 34 resistor l MEG l 0 36 capacitor Cornell MPY2W2 2 mfd 1.47

Dubilier 37 resistor 44 MEG .IO 40 diode GE IN9I4 .30 41 battery Eveready 216 9 volt .49 42 battery Eveready 2l6 9 volt .49

Total 25.1 I

From the foregoing description, it may be appreciated that the circuit of FIG. 2 could signal the local desk in an apartment house or even the local police department over electrical leads in order that the premises could be checked to determine whether the entry was unauthorized. Naturally, the user would enter and switch the mode or otherwise disable the remote actuated alarm signal, but even in the absence of a remote alarm, the device positively signals illegal entry or entry by someone other than the user, and thus eliminates the problem of guessing whether an assailant lies in wait or whether or not the apartment was violated regardless of whether it was left locked or unlocked.

The packaging of the device (FIG.'3) is preferably a box A of any composition with dimensions of 6 inches long, 3% inches wide, and 2 inches deep that houses all the electronics of the alarm except the doorbell switch B, and a similar box C with dimensions of 3 inches long, 2 inches wide and 1 inch deep that contains the doorbell switch B. The two boxes are connected together by an adjustable tempered steel bracket D that allows the total assembly J to be adjustedto and clamped over the top or side of an open door E. The bracket D can be adjusted from We inch to 1 inch to accommodate most usually encountered door thicknesses. The bracket D conceals and protects the bell wires from tampering and possible damage should the tolerance between the door E and the doorframe F be too close. The inside of the bracket D and the back of the large box A are coated with a rubbery material to provide additional protection for the wires and a nonslipping grip on the door E by the assembly J. After installation (which usually takes about 15 seconds), the door should close easily.

From the outside of the door, the part of the assembly I that is seen is the doorbell button box C which is attached to a thin but strong L-shaped piece of steel (bracket D) which disappears between the door E and the doorframe F. Inside the door, the bracket D is attached to the large box A by finger manipulated locks G which allow the assembly to be adjusted by use'of slots I, but not disassembled. The microswitch actuator H protrudes through the large box A and bracket D and is restrained by the doorframe F when the door E is closed. When the door opens, the microswitch actuator H is no longer restrained by the doorframe F as when the door E is closed, and the contacts close causing the proper electronic reaction. It can be seen that this arrangement, without modification, is only applicable to doors which open to the inside, however, this is practically always the case.

What is claimed is:

1. Signalling apparatus for guarding a closure against undesirable penetration via an access comprising in combination memory means actuable to a first condition upon violation of the closure access; interrogatable circuit means comprising sound emitter means and switching means; said sound emitter means responsive to said memory actuable means for indicating past violation of the closure access when interrogated via the switching means; and means including the sound emitter means responsive to said actuable means in a second condition for immediately indicating present violation of the closure access without requiring interrogation.

2. The apparatus of claim 1 wherein the memory means comprises a door or window actuated switch and on ON-OFF device.

3. The apparatus of claim 2 wherein the switching means comprises a manual switch deployed externally of the closure in a first path for interrogating the memory means and operating the sound emitter means accordingly.

4. The apparatus of claim 3 comprising timer means in a second path for operating the sound emitter means for a predetermined length of time; and means connecting the timer means to the door or window actuated switch to activate the sound emitter means by actuation of said switch.

5. The apparatus of claim 3 wherein at least a portion of the switching means comprises a third path for actuating the sound means and further comprising current limiting means connected in said third path to modify the sound of the sound emitter means.

6. The apparatus of claim 1 comprising key operated switching means selectively operable to a memory mode or an attended mode; said key operated switching means respectively establishing at least partly separate paths between the memory means and the sound emitter means; and said manual switch being in the memory mode separate path.

7. Signalling apparatus for guarding a closure having an egress comprising first switching means actuable upon violation of the egress; sound emitter means; cir cuit means for connecting the sound emitter means to be activated upon switching of the first switching means; memory means actuable upon switching of the first switching means; further switching means precluding operation of the sound emitter means until the memory means is interrogated; and means accessible without violation of the egress for interrogating the memory means.

8. The apparatus of claim 7 comprising means connected in circuit with the sound emitter ,means for changing its sound.

9. The apparatus of claim 8 further comprising timing means and third switching means for operating the sound emitter means whenever the egress is violated.

10. The method of safeguarding access to a closure comprising the steps of: deploying a signalling vice within the closure; locating an interrogating switch externally of the closure; connecting the switch with a memory circuit; interconnecting the memory circuit, a switch actuable by violation of the closure, and the signalling device; and modifying the sound from the signalling device for one of the conditions of violation or non-violation of the access to the closure to be detected upon interrogation of the memory by actuation of the external switch.

11. The method of claim 10 wherein the modifying step comprises establishing a path for the signalling device by way of current control means to modify the sound from the signalling device if the switch actuable by violation of the closure is actuated.

12. The method of claim 11 comprising the further step of: establishing an attended signalling path for the signalling device via the memory for energization of the signalling device if the switch actuable by violation of the closure is actuated; and disabling the connecting of a switch with a memory circuit and the interconnecting the memory circuit, a switch actuable by violation of the closure, and the signalling device.

13. The method of claim 1 1 further comprising establishing another path for actuating the signalling device when the switch actuable by violation of the closure is actuated; and timing the last mentioned actuating of the signalling device for a predetermined period of actuation.

14. The method of detecting unauthorized violations of a closure upon opening an access thereto, comprising the steps of: v

locating a switch for operation to a first position upon opening the access and to a second position upon closing the access;

switching a key switch to an attended alarm position and opening the access to latch a latching device and sound an alarm; switching said key switch to a memory position to quiet the alarm and closing the access to leave the latching device latched; unlatching the latching device upon subsequent opening of the access but without sounding the alarm; and interrogating the latching device via the alarm from a further switch external to the closure to determine if the closure had been violated since the key switch was switched to the memory position.

15. The method of claim 14 wherein the interrogating step includes modifying the alarm sound if the closure had been violated.

16. The method of claim 14 including the further step of: sounding the alarm for a predetermined period upon violation of the closure.

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4284981 *May 19, 1980Aug 18, 1981Black Robert BSensor alarm and support
US4611200 *Oct 24, 1984Sep 9, 1986Stilwell Fred WPortable battery powered smoke detector and clock
US5072212 *Dec 17, 1990Dec 10, 1991Sorenson Gary REntry alarm
US5321390 *Sep 28, 1992Jun 14, 1994John Manufacturing LimitedSensor switch
US9522650 *Jul 10, 2014Dec 20, 2016Vasil W. TurjancikMicro motion warning device with none false alarm systems
Classifications
U.S. Classification340/546, 340/691.8
International ClassificationG08B13/02, G08B13/08
Cooperative ClassificationG08B13/08
European ClassificationG08B13/08