US3623088A

US3623088A - Alarm system with manually selectable time delay

Info

Publication number: US3623088A
Application number: US843446A
Authority: US
Inventors: Ronald C Peterson
Original assignee: Peterson Design Co Inc
Current assignee: Peterson Design Co Inc
Priority date: 1969-07-22
Filing date: 1969-07-22
Publication date: 1971-11-23
Anticipated expiration: 1988-11-23

Abstract

An alarm system for detecting the presence of either an intruder or a fire, having a general purpose relay connected to a sensing circuit and operative in conjunction with a transformer power supply to energize an alarm either immediately or, in conjunction with a time delay relay, after a predetermined delay period has expired. A selector switch coupled to both the general purpose relay and the time delay relay controls the system to cause the alarm to be energized either immediately after an intruder (or fire) is sensed or after the termination of the predetermined delay period beginning at the time of entry of the intruder.

Description

United States Patent XX X n m m 4 6 Q7W7A0 5Q3Q3 0 0 4 4 3 3 mn m mm "may!" mid r i3 wMwHC 45579 66666 99999 HHHHH 829 29324 92995 57030 58007 33333 c n l y m n m m c mo 1m 7 Pn .0 ll m a n n 23 mmmnam 3 V wa R JNP 0. de m N mm P .L ng 6 emia m p as 1 AFPA 11]] 2 [253 7 2247 l .llll

Primary Examiner--.lohn W. Caldwell Assislan! Examiner-William M. Wannisky AnorneyMarshall A. Lerner Washington, D.C.

[54] ALARM SYSTEM WITH MANUALLY ABSTRACT: An alarm system for detecting the presence of tive in conjunction immediately or, in conjunction with a tim predetermined delay period has expire coupled to both the general purpose relay and the time del 4 4 7M M 2/ 2 I 3 ol o u b4 .8 60 766 n .0 w mmm 3 Mn 7 m m 2 new w mm m 4 m m 3 m m h m M M I. I o C d L M h F l l 1 0 5 5 l .l.

274, 280, 256, 420; 335/236 controls the system to cause the alarm to be energized either or after the period beginning at immediately after an intruder (or fire) is sensed termination of the predetermined delay the time ofentry of the intruder.

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PATENTEDHUV 23 I97! 3,623,088

SHEET 1 UP 2 INVI'INTUR Ronald C. PCferSon MWALUM ATTORNIz'Y PATENTEDxuv 23 |97| SHEET 2 [IF 2 INVEN'I'OR Ron 0 Id C. Pe fersnn FIG. 6.

MWPWJU A W ATT( )RNI'IY Heat Sensor Of her Sensors ALARM SYSTEM WITH MANUALLY SELECTABLE TIME DELAY BACKGROUND OF INVENTION 1. Field of Invention The present invention relates to an alarm system and more particularly to a system for activating an alarm immediately intruder has entered the protected premises (or after a fire is sensed) or after a predetermined delay, beginning the moment of entry of the intruder, has expired. The delay feature enables authorized personnel to enter the premises and deactivate the system prior to the energization of the alarm.

2. Description of the Prior Art In the field of alarms, numerous prior art devices have been employed to signal the presence of unauthorized personnel or of a fire. Such devices have generally been unsatisfactory for use in residential and decorative commercial interiors. The defects in such devices are characterized by a high rate of false alarms and ease of defeat of intruders with knowledge of the alarm systems weaknesses. In addition, such systems are complex, inconvenient to operate, and expensive to install.

One such prior art system utilizes a key-operated lock to permit authorized personnel to enter and leave the protected premises without energizing the alarm. Such locks are usually mounted on the alarm housing or installed in the doorway of the premises. They have not, however, provided adequate protection since they are easily picked.

Still other prior art devices are mountable on the doors of the protected premises. Such devices have proven unsatisfactory in view of the fact that they may be easily short circuited and rendered inoperative by forcing moisture through apertures in the housing.

Further prior art systems which are currently gaining popularity utilize capacitive, sonic, ultrasonic, and photoelectric sensing techniques. Such devices, however, are sensitive to environmental conditions and are not completely reliable over a wide range of conditions of temperature and humidity. In addition, they are subject to electrostatic and mechanical disturbances as well as powerline voltage fluctuations and other transient voltages.

Some systems utilize automatic telephone dialing equipment. Such systems are becoming increasingly undesirable due to the high incidence of false alarms.

SUMMARY OF THE INVENTION The general purpose of this invention is to provide an alarm system for protecting residential or decorative commercial premises which embraces all the advantages of similarly employed prior art devices and possesses none of the aforedescribed disadvantages. To attain this, the present invention provides a general purpose latching relay coupled to a sensing device and a time delay relay. A selector switch controls the system to energize the alarm either immediately upon the entry of unauthorized personnel or after the termination of a predetermined delay period. The purpose of the selection of the two modes of operation is to provide protection for the premises when authorized personnel are inside the premises as well as when no authorized personnel are inside the premises. The selector switch may be set to energize the alarm immediately upon the entry of an intruder when authorized personnel are inside the premises. However, in order to avoid the immediate energization of the alarm when authorized personnel enter the premises, the selector switch may be set, prior to leaving the premises, to the Away" position. Under such conditions, such authorized personnel may enter the premises and reach the selector switch and deactivate the system prior to the energization of the alarm. Thus, the sounding of a false alarm is prevented. The alarm is further disguised as a small speaker case to prevent its identification by unauthorized personnel.

According to the present invention, one terminal of a standard l 17 volt AC house current power supply is connected to a selector switch having two ganged contacts and three switch positions for each contact. One switch position is open circuited and causes disengagement of the entire system. The selection of a second switch position, referred to as the ln" position, causes the alarm to sound immediately upon the sensing of unauthorized personnel. The selection of a third switch position, referred to as the "Away" position, causes the alarm to sound after the termination of a predetermined time period beginning at the instant the premises are entered. Both the In" and Away" terminals of the selector switch associated with one of the contacts are coupled to one end of the primary winding of a standard stepdown transformer. The other end of the winding is connected to the second terminal of the AC power supply. The In" and Away" terminals associated with this first contact of the selector switch are coupled to one terminal of a general purpose latching relay having two ganged contacts and two terminals, each associated with one of said contacts. In" and "Away" terminals are also connected to the armature contact of a time delay relay.

The stationary contact of the time delay relay is connected to the Away" terminal associated with the second contact of the selector switch. The In terminal associated with this second contact of the selector switch is connected to the armature associated with the first stationary contact of the general purpose latching relay as well as the control element of the time-delay relay. The other end of the control element of the time-delay relay is connected to the second terminal of the AC power supply. I

The second contact of the selector switch is connected to one terminal of an alarm mechanism. The alarm mechanism is preferably an alarm bell. However, the alarm may be any other standard alarm device. The second terminal of the alarm device is connected to the second terminal of the AC power supply.

The secondary of the transformer circuit is connected in series to the solenoid of the general purpose latching relay. The sensing devices are connected in series in the secondary circuit of the transformer. .The sensing device is preferably a standard shunt magnetic switch having two elements with one element containing a permanent magnet. One element may be mounted on the door of the premises and the other element is mountable on the door post so that when the door is closed, the elements are in juxtaposition with one another. When the door is opened, the contacts are closed. A heat-sensing device for detecting fires may be coupled in parallel with the shunt magnetic sensor in the transformer secondary circuit. The magnetic sensing and heat-sensing devices are both well known in the art.

The second stationary contact of the general purpose latching relay is coupled to the solenoid of the general purpose latching relay. The armature associated with the second contact is coupled to the secondary circuit and effectively latches the secondary circuit causing a remaining closed loop once the sensing contacts are closed.

When the selector switch is in the "Off" position, the system is completely passive and inoperative. If a user is inside the premises and desires to have the alarm sound immediately upon entry of any unauthorized personnel, the selector switch is set to the ln" position. The primary circuit of the transformer is thus energized. Upon the opening of the door of the premises, the magnetic sensors close the secondary circuit thereby energizing the solenoid of the general purpose latching relay. Both arrnatures are thereby activated to close both contacts of the general purpose latching relay. The closure of the first contact causes the alarm to be in series with the AC power supply thereby causing the alarm to sound a warning immediately. The closure of the second contact latches the relay and causes the circuit to remain closed until the selector switch is turned to the Off position.

If the user wishes to leave the premises, the selector switch may be set to the Away" position prior to leaving. The user may depress the shunt pole of the magnetic sensor before opening the door. The sensor contacts remain open even after the user ceases to depress the shunt pole. After the door is closed the shunt pole is automatically released by the action of the magnet and the system is armed.

Upon the opening of the door, the sensor contacts are closed thereby closing and latching the contacts of the general purpose relay in the same manner that the contacts are closed when the selector switch is in the In" position. Power is supplied from the AC source to the control element of the time delay relay through the Away contact of the selector switch through the first armature of the general purpose latching relay. If the person entering the premises is an unwanted intruder, after the termination of the delay period of the time delay relay, the contacts of the time delay relay are closed. Power is thus supplied from the AC source to the alarm bell through the Away" contact of the selector switch associated with the first armature, through the contacts of the time delay relay and through the away contacts of the selector switch associated with the second armature to the energizing mechanism of the bell. In the event that the door is opened by some authorized personnel who presumably is familiar with the location of the selector switch of the system, such personnel may proceed immediately to the switch and manually turn it to the Off position prior to the termination of the delay period. Thus a false alarm is avoided. Similarly, turning the system from Away" to In" will simultaneously turn the unit off, disengage the latching relay, and turn the unit back on.

The action of the selector switch is thus that if the switch is operated too quickly, as in a panic state of an intruder, the relay will not have time to disengage and the system will continue to operate until disconnected from a power supply.

Thus the system is operative to sense immediately the presence of an unwanted intruder when the selector is in the In position. When the selector switch is in the "Away" position, the system is operable to detect the presence of an intruder after the termination of the period of the time delay. In the event that the door of the premises is opened by some authorized person, such a person may proceed to the selector switch and manually turn it to the 01? or in" position to prevent the sounding of a false alarm.

In a second embodiment, the sensors are arranged in series in the secondary circuit. All the contacts of the sensors are in the normally closed position and the solenoid of the general purpose latching relay is normally activated and latched. The stationary contact with which the first armature of the latching relay is associated is open circuited and the other stationary contact associated with the same armature is coupled to the In" and "Away" terminals associated with the first armature of the selector switch.

In the operation of the second embodiment, the contacts of the sensors are all normally closed and the solenoid of the latching relay is normally energized. In the event that one of the contacts is opened, indicating the presence of an intruder of the sensing of a fire, the secondary circuit is opened and the solenoid of the latching relay is deenergized The first armature of the latching relay is released from the open-circuited terminal and makes contact with the terminal coupled to the In and Away" terminals associated with the first armature of the selector switch. The operation of the circuit is the same as that of the first embodiment in all other respects.

Accordingly, an object of the present invention is to provide signalling means.

Another object of the present invention is to provide burglar and fire alarm means.

Another object of the present invention is to provide means to protect residential or decorative commercial premises from an intruder or a fire.

Yet another object of the present invention is to provide means to sound an alarm immediately upon the entry of unauthorized personnel into the premises sought to be protected.

Still another object of the present invention is to provide alarm means which may be anned prior to leaving the premises such that upon reentry, the alarm is not energized until the termination of a predetermined delay period.

Thus another object of the present invention is to provide alarm means capable of being set to be energized immediately upon the entry or" an intruder when authorized personnel are on the premises sought to be protected. It further has the capacity of being set prior to the ieaving of authorized personnel to be energized upon reentry into the premises after the termination of a predetermined delay period. It thereby permits such authorized personnel to deactivate the system prior to the termination of the predetermined delay period to thereby avoid false alarms.

Another object of the present invention if to provide tamper-proof alarm means characterized by ease of installation and operation, and insensitivity to wide ranges of environmental conditions.

Yet another object of the present invention is to provide highly reliable and inexpensive alarm means which is devoid of locks and other such means which are subject to tampering.

Still a further object of the present invention is to provide flexible alarm means operable to sense various physical parameters and mountable in such a manner as to camouflage its function from unauthorized personnel.

Other objects, advantages and novel features of the present 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 of the alarm housing; and

FIG. 2 is a view in perspective of the rear panel of the housing; and

FIG. 3 is a view of a shunt magnetic sensor and attendant magnet; and

FIG. 4 is an exploded view of the contents of the alarm housing; and

FIG. 5 is a circuit diagram of the preferred embodiment; and

FIG. 6 is a partial circuit diagram of a second embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG. 1, there is shown casing I0 for the alarm system having a speaker grille 11. In the preferred embodiment the casing is designed to have the appearance of a household item such as a stereo speaker. The casing, however, may be designed to be compatible with any interior decor. The selector switch 12 is mounted on casing 10 so as to be manually adjustable.

FIG. 2 is a rear view of housing 10 having back panel 13 which furnishes protection for the unit. Power for the system is supplied from a standard house current AC source through cord 14. Binding

posts

15 and 16 provide interface between sensor circuitry and the rest of the system. Power outlet 17 is coupled in parallel to the alarm circuitry located within casing I0 and permits the coupling of an alarm located in a remote area to the system.

The magnetic sensor having a shunt feature used in the preferred embodiment is shown in FIG. 3. The magnetic switch is housed in container 18 and is operative in conjunc tion with a fixed magnet housed in container 19. A shunt pole 20 is provided on container 18 and

terminals

21 and 22 are connected to internal contacts of the sensor in housing 18. One of the containers is mounted on a door of the premises sought to be protected. The other is mounted on the doorpost so that the two containers are in juxtaposition when the door is closed. Under such circumstances, the internal contacts are open and the system is in a passive state. When the door is opened, the internal contacts are closed and the alarm system, which will be explained subsequently, is energized. In order to leave the premises without closing the sensor contacts, the shunt pole is depressed and the door is opened. The effect of depressing the shunt pole while opening the door is to prevent the sensor contacts from closing. Once the door is closed, the shunt pole is released and the sensors are armed. Such devices are well known in the art and are exemplified by the line of shunt magnetic switches manufactured by the Alarm Device Manufacturing Company.

FIG. 4 shows an arrangement of the components of the system on a chassis 24 which is secured to the wooden base of the housing 10. The chassis is secured to the housing by means of screws, adhesives, or any other standard securing means. A time delay relay 25 is mounted on the chassis. The time delay relay may be any switching device having a delay control element such as a resistance-capacitive network, an air dashpot, a unijunction diode in connection with a resistance-capacitive network, an elongated thermal contact, a bimetallic contact type, or a motor drive. Such time delay relays are well known in the art.

A power transformer 26 is also mounted on the chassis. Such a transformer is well known in the art and may be a class II foot-mounted step-down transformer employing a l I0-l20 volt AC primary winding and a 24 volt center tap AC secondary winding. The contacts of the selector switch 12 and the alarm are in the primary circuit of the transformer. The sensor circuit is in the secondary winding.

A general purpose latching relay 27, mounted on chassis 24, is operative to implement the logic circuitry. Relay 27 may be a standard relay employing a ferro-magnetic core and movable contacts. A thermostatically operated switch 28 is mounted on chassis 24. Switch 28 is operative to energize the alarm when a fire is sensed. The underside of selector switch 12 is shown mounted on the cabinet. A warning device such as bell 29 may be mounted on the side of cabinet as shown in FIG. 4. Any standard prior art bell may be used. However, in the preferred embodiment, the bell is a 75 decibel rated underdome vibrating alarm bell.

FIG. 5 is a circuit diagram of the preferred embodiment of the present invention. Power is supplied from a standard 117 volt AC power supply applied through socket 35 to armature 36 of selector switch 12. Armature 36 is ganged with armature 37 of the selector switch. The selector switch may be set to the 011" position by manually moving armatures 36 and 37 to make contact with

terminals

38 and 39 respectively. The selector switch may be set to the In" position by manually moving armatures 36 and 37 to make contact with terminals 49 and 41 respectively. Similarly, the selector switch may be set to the Away" position by manually moving armatures 36 and 37 to make contact with terminals 42 and 43.

In" terminal 40 and Away" terminal 42 of the selector switch 12 are coupled to the primary winding 50 of transformer 26.

Terminals

40 and 42 are further connected to ter minal 60 of the general purpose latching relay 27 as well as armature 70 of the time delay relay 25. The in" terminal 41 of selector switch 12 is also connected to terminal 61 of general purpose latching relay 27. The Away terminal 43 ofselector switch 12 is connected to terminal 71 of time delay relay 25.

General purpose latching relay 27 contains

armatures

63 and 64 ganged to operate in unison. As shown, armature 63 connects

terminals

60 and 61 when in the closed position and armature 64 connects

terminals

62 and 65 when in the closed position. The movement of

armatures

63 and 64 is controlled by solenoid 66 and terminal 62 is connected to solenoid 66 for latching purposes whenever the solenoid is energized. Terminal 60 is connected to the primary of transformer 26 and terminal 61 is connected to control element 73 of time delay relay 25 Solenoid 66 is connected to secondary winding 51 of transformer 26.

Terminals

62 and 65 are also connected in the secondary circuit for latching purposes. Heat sensor 28 is connected in the secondary circuit in parallel with a magnetic sensor. Heat sensor 28 contains armature 80 and terminals 81. When a predetermined allowable temperature is sensed, armature 80 is activated to close the secondary circuit at terminal 81.

Magnetic sensor element 18 contains an armature 83 which closes the secondary circuit at terminal 22 when

elements

18 and 19 are separated, unless shunt pole is depressed. Element 19 contains a permanent magnet 84 which attracts armature 83 to cause it to be in the normally open position. A mechanical spring 85 urges the armature toward the closed position when

elements

18 and 19 are separated. Shunt pole 20 contains a clip 87 which engages armature 83 when depressed prior to the separation of

elements

18 and 19, thereby preventing armature 83 from closing the secondary circuit at terminal 22. When

elements

18 and 19 are again brought together upon the closing of the door on which they are mounted, permanent magnet 84 attracts armature 83 away from shunt pole 20. Armature 83 is thereby released from clip 87 of shunt pole 20 and the sensors are armed to close the secondary circuit upon the subsequent separation of

elements

18 and 19 by the opening of the door on which they are mounted.

Control element 91 of alarm bell 29 is connected at terminal 93 to the main power supply 35. The other terminal 92 of control element 91 is connected to armature 37 of selector switch 12.

Terminals

94 and 95 are connected in parallel with

tenninals

92 and 93 to accommodate any of the warning device.

In the embodiment of the invention shown in FIG. 6, the sensors are arranged in series in the secondary circuit. Armature 83 of the magnetic sensor is normally coupled to terminal 88 which is coupled in series with heat sensor 28 (shown in block diagram form). Other sensors may be connected in series in the secondary circuit as shown. Terminal 60 of the latching relay is open-circuited and terminal 60A is coupled to the selector switch. The construction of the embodiment of FIG. 6 is similar to that of FIG. 5 in all other respects.

In the operation of the circuit shown in FIG. 5, armatures 36 and 37 are initially set to the Off" position to engage

terminals

38 and 39. Under such circumstances, the system is totally deenergized. When a user is inside the premises and desires to have the alarm sound immediately upon the entry of an intruder, the selector switch is set to the In" position by manually moving contacts 36 and 37 to engage terminals 40 and 41 respectively. If an intruder opens the door of the premises,

elements

18 and 19 of the magnetic sensor, which are mounted on the doorpost and door respectively, are separated. Permanent magnet 84 no longer exerts a magnetic force on armature 83 and spring 85 causes armature 83 to close the secondary circuit at terminal 22. The closure of the secondary circuit causes the solenoid 66 of the latching relay 27 to be energized thereby causing

armatures

63 and 64 to engage

terminals

60 and 62 respectively. The coupling of armature 64 to terminal 62 latches the relay. The coupling of armature 63 to terminal 60 causes the application of power from source 35 via terminal 41, armature 37 and terminal 92 to control element 91 of alarm 29. Thus, the alarm is sounded.

It will be appreciated that in the event that the temperature in the vicinity of the system exceeds the allowable limits, armature of heat sensor 28 will close the secondary circuit at tenninal 81 to thereby cause the circuitry to operate in a similar manner to energize the alarm. Thus, the alarm is energized immediately upon the opening of the door or the activation of the heat sensor when the selector switch is in the In" position.

In order to arm the system before leaving the premises, the selector switch 12 is shifted to the Away position so that armatures 36 and 37 engage contacts 42 and 43 respectively. Before leavingthe premises, the shunt pole 20 of magnetic sensor element 18 is depressed and the door is opened thereby separating

elements

18 and 19. The magnetic force of bar magnet 84 on armature 83 is released and spring urges armature 83 toward terminal 22. However, since shunt pole 20 is depressed, armature 83 is engaged by clip 87 and does not close the secondary circuit. When the door is closed upon leaving the premises, the magnetic force of magnet 84 is effective to urge armature 83 toward bar magnet 84 and release it from clip 87 of shunt pole 20. The user is thus able to leave the premises with the system armed without setting off the alarm.

in the event that an intruder enters the premises, spring 85 urges armature 83 toward terminal 22 to thereby close the secondary circuit. Solenoid 66 of relay 27 is energized and armature 64 latches the relay when in contact with terminal 62. Armature 63 closes the circuit at terminal 60 thereby applying power to the control element 73 of the time delay relay 25 from power source 35 via armature 36, terminal 42, terminal 60, and armature 63. After the termination of the predetermined time delay, armature 70 engages terminal 71 causing the application of power to the control element 91 of alarm 29 from the power source 35 via armature 36, terminal 42, armature 7G, terminal 71, terminal 43, armature 37, and terminal 92. It will be appreciated that in the event that heat sensor 28 detects a temperature in the vicinity of the system which is in excess of the allowable limitations, armature 80 engages terminal 81 and closes the secondary circuit to ultimately cause the sounding of the alarm in a similar manner. The user, upon entering the premises, however, may proceed directly to the selector switch and turn it to the Off" position to prevent the sounding of a false alarm.

in the embodiment shown in FIG. 6, the contacts of all of the sensors are arranged in series and the solenoid 66 is thus normally energized. Armature 64 thus engages terminal 62 and relay 27 is latched. Armature 63 engages open-circuited terminal 60. When an intruder or a fire is sensed, the sensor contacts are opened and the solenoid 66 is deenergized. Armatures 63 and 64 are thus coupled to terminals 60A and 62A respectively. Relay 27 becomes unlatched and the connection of armature 63 to terminal 60A causes the activation of the alarm in the same manner as it is activated in the first embodiment.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. For example; the sensors need not be heat sensors or magnetic sensors. The system may be adapted to be operable in conjunction with any other kind of sensor. Furthermore, although the preferred embodiment discloses a bell alarm, any other form of alarm or utilization device may be coupled to the system at

terminals

94 and 95. The system may be used in conjunction with an audiovisual utilization means or any visual display device to indicate the presence of an intruder or the sensing of a fire. in addition, the system may be used as a signalling device operative to energize any utilization device either immediately after an event or after a predetermined delay period has expired. The event need not be an undesirable event such as the presence of an intruder or the detection of a fire.

it is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. Alarm means for producing a warning signal either immediately after the premises sought to be protected are entered by unauthorized personnel or after the termination of a delay period during which authorized personnel may either leave the premises without the alarm system being armed until said authorized personnel has left said premises or enter said premises and adjust said alarm means to prevent the system from generating a false alarm comprising:

A power source:

first switching means coupled to said power source and settable to select a first mode of operation wherein the warning signal is produced immediately after the premises sought mode be protected are entered by unauthorized personnel, said first switching means comprising a plurality of manually selectable ganged armatures and a plurality of sets of terminals each associated with one of said armatures with each terminal of each of said plurality of sets of terminals associated with a different MODE of operation;

a sensor for sensing the occurrence of an undesired event;

a second switching means having a contact element coupled to said first switching means and a control element coupled to said sensor;

third switching means of a time delay type having a contact element coupled to said first switching means and a control element coupled to said second switching means and operative to activate said contact element of said third of means of a time delay type after the termination of a predetermined delay period during which said control element OF said third switching means is energized to permit authorized personnel to either leave said premises without said alarm system being armed until said authorized personnel has left said premises or enter said premises and adjust said alarm means to prevent said system from generating a false alarm; and

alarm means coupled to said first switching means to produce the warning signal immediately upon the occurrence of the undesired event when said first switching means is set to said first mode of operation, and to produce the warning signal after the termination of a delay period when said first switching means is set to said second mode of operation.

2. The system as described in claim 1 further containing a plurality of sensors in parallel with said sensor and wherein said control element of said second switching means is normally deenergized when no warning signal is being produced.

3. The system as described in claim 2 wherein at least one of said sensors is a magnetic sensor switch.

4. The system as described in claim 3 wherein said magnetic sensor switch contains a shunt pole arrangement which is operable to prevent the closing of said magnetic switch.

5. The system as described in claim 1 further containing a plurality of sensors in series with said sensor and wherein said control element of said second switching means is normally energized when no warning signal is being produced.

6. The system as described in claim 5 wherein at least one of said sensors is a heat sensor.

7. The system as described in claim 5 further containing a transformer having a primary winding coupled to said first switching means and a secondary winding coupled in series between one of said sensors and said control element of said second switching means 8. The system as described in claim 7 further containing a housing camouflaged as a small stereo speaker.

9. Signalling means for producing a signal either immediately after a specified event or after the termination of a delay period subsequent to the occurrence of the event comprising:

a power source;

first switching means coupled to said power source and settable to select a first mode of operation wherein the signal is produced immediately after the occurrence of the undesired event or a second mode of operation wherein the signal is produced after the termination of a delay period, said first switching means comprising a plurality of manually selectable ganged armatures and a plurality of sets of terminals each associated with one of said armatures with each terminal of each of said plurality of sets of terminals associated with a different mode of operation;

a sensor for sensing the occurrence of the specified event;

second switching means having a contact element coupled to said first switching means and a control element coupled to said sensor;

third switching means of a time delay type having a contact element coupled to said first switching means and a control element coupled to said second switching means and operative to activate said contact element of said third switching means of a time delay type after the termination of a predetermined delay period during which said control element of said third switching means is energized; and

a utilization device coupled to said first switching means to produce the signal immediately upon the occurrence of the specified event when said first switching means is set to said first mode of operation, and to produce the signal after the termination of a delay period when said first switching means is set to said second mode of operation.

10. The system as described in claim 9 further containing a plurality of sensors in parallel with said sensor and wherein said control element of said second switching means is normally deenergized when no signal is being produced.

11. The system as described in claim 10 wherein said second switching means comprises a relay. and said control element of said second switching means comprises a solenoid, and said contact element comprises a plurality of ganged armatures and a plurality of terminals each associated with one of said armatures, with at least one of said armature and terminal combinations operable to latch said second switching means.

12. The system as described in claim 10, wherein said third switching means of a time delay type is of the elongated thermal contact type.

13. The system as described in claim 9 further containing a plurality of sensors in series with said sensor and wherein said control element of said second switching means is normally energized when no signal is being produced.

14. The system as described in claim 13 wherein at least one of said sensors is a magnetic sensor switch.

15. The system as described in claim 14 wherein said mag netic sensor switch contains a shunt pole arrangement which is operable to prevent the closing of said magnetic switch.

16. The system a described in claim 13 wherein said first switching means comprises a plurality of manually settable ganged armatures and a plurality of sets of terminals each associated with one of said armatures with each terminal associated with a different mode of operation.

17. The system as described in claim 13 wherein said second switching means comprises a relay, and said control element of said second switching means comprises a solenoid, and said contact element comprises a plurality of ganged armatures and a plurality of terminals each associated with one of said annatures, with at least one of said armature and terminal combinations operable to latch said second switching means.

18. The system as described in claim 31 wherein said third time delay switching means is of the elongated thermal contact type.

19. The system as described in claim 13 wherein said utilization device comprises an audiovisual device.

i i i i i

Claims

1. Alarm means for producing a warning signal either immediately after the premises sought to be protected are entered by unauthorized personnel or after the termination of a delay period during which authorized personnel may either leave the premises without the alarm system being armed until said authorized personnel has left said premises or enter said premises and adjust said alarm means to prevent the system from generating a false alarm comprising: a power source; first switching means coupled to said power source and settable to select a first mode of operation wherein the warning signal is produced immediately after the premises sought to be protected are entered by unauthorized personnel, said first switching means comprising a plurality of manually selectable ganged armatures and a plurality of sets of terminals each associated with one of said armatures with each terminal of each of said plurality of sets of terminals associated with a different mode of operation; a sensor for sensing the occurrence of an undesired event; a second switching means having a contact element coupled to said first switching means and a control element coupled to said sensor; third switching means of a time delay type having a contact element coupled to said first switching means and a control element coupled to said second switching means and operative to activate said contact element of said third switching means of a time delay type after the termination of a predetermined delay period during which said control element of said third switching means is energized to permit authorized personnel to either leave said premises without said alarm system being armed until said authorized personnel has left said premises or enter said premises and adjust said alarm means to prevent said system from generating a false alarm; and alarm means coupled to said first switching means to produce the warning signal immediately upon the occurrence of the undesired event when said first switching means is set to said first mode of operation, and to produce the warning signal after the termination of a delay period when said first switching means is set to said second mode of operation.

7. The system as described in claim 5 further containing a transformer having a primary winding coupled to said first switching means and a secondary winding coupled in series between one of said sensors and said control element of said second switching means.

8. The system as described in claim 7 further containing a housing camouflaged as a small stereo speaker.

9. Signalling means for producing a signal either immediately after a specified event or after the termination of a delay period subsequent to the occurrence of the event comprising: a power source; first switching means coupled to said power source and settable to select a first mode of operation wherein the signal is produced immediately after the occurrence of the undesired event or a second mode of operation wherein the signal is produced after the termination of a delay period, said first switching means comprising a plurality of manually selectable ganged armatures and a plurality of sets of terminals each associated with one of said armatures with each terminal of each of said plurality of sets of terminals associated with a different mode of operation; a sensor for sensing the occurrence of the specified event; second switching means having a contact element coupled to said first switching means and a control element coupled to said sensor; third switching means of a time delay type having a contact element coupled to said first switching means and a control element coupled to said second switching means and operative to activate said contact element of said third switching means of a time delay type after the termination of a predetermined delay period during which said control element of said third switching means is energized; and a utilization device coupled to said first switching means to produce the signal immediately upon the occurrence of the specified event when said first switching means is set to said first mode of operation, and to produce the signal after the termination of a delay period when said first switching means is set to said second mode of operation.

11. The system as described in claim 10 wherein said second switching means comprises a relay, and said control element of said second switching means comprises a solenoid, and said contact element comprises a plurality of ganged armatures and a plurality of terminals each associated with one of said armatures, with at least one of said armature and terminal combinations operable to latch said second switching means.

12. The system as described in claim 10 wherein said third switching means of a time delay type is of the elongated thermal contact type.

15. The system as described in claim 14 wherein said magnetic sensor switch contains a shunt pole arrangement which is operable to prevent the closing of said magnetic switch.

16. The system as described in claim 13 wherein said first switching means comprises a plurality of manually settable ganged arMatures and a plurality of sets of terminals each associated with one of said armatures with each terminal associated with a different mode of operation.

17. The system as described in claim 13 wherein said second switching means comprises a relay, and said control element of said second switching means comprises a solenoid, and said contact element comprises a plurality of ganged armatures and a plurality of terminals each associated with one of said armatures, with at least one of said armature and terminal combinations operable to latch said second switching means.

18. The system as described in claim 13 wherein said third time delay switching means is of the elongated thermal contact type.