US3239830A - Power line alarm responsive to plural current interruptions in a predetermined time - Google Patents

Description

March 8, 1966 R, sc n- 3,239,830

POWER LINE ALARM RESPONSIVE TO PLURAL CURRENT INTERRUPTIONS IN A PREDETERMINED TIME Filed Dec. 24, 1959 2 Sheets-Sheet 2 INVENTOR ROBERT T SCH/W77 ATTORNEYS United States Patent 3,239,830 POWER LINE ALARM RESPONSIVE TO PLURAL CURRENT INTERRUPTIONS IN A PREDETER- MINE!) TIME Robert T. Schmitt, 15554 Mercury Drive,

Grand Haven, Mich. Filed Dec. 24, 1959, Ser. No. 462 7 Claims. (Cl. 340-310) This invention relates to a universal, emergency alarm system. More particularly, it relates to an alarm system for use in conjunction with the community electrical power system.

This application is a continuation-in-part of United States patent application Serial No. 836,378, filed August 27, 1959, by Robert T. Schmitt for Universal Emergency Alarm System, now abandoned.

The need and problem of alerting the people of a community to a national and local emergency situation has become most acute within recent years. Advancements in weather forecasting and sighting have made possible the giving of advance notice to communities of hurricane and tornado conditions. For this a warning system is needed. Advancements in nuclear energy warfare and in intercontinental ballistic missiles also make necessary a community warning system.

Attempts have been made to solve this problem. Thus, in many communities there have been provided sirens at strategic locations within the community, which sirens are under the control of the local police or of the local civil defense authorities. Of course, giving warning by means of public announcements over radio and television is also being done.

However, none of these ways of alerting and warning a community are as effective as desired. A substantial share of the population of a local community may not have their radio and television sets turned on at the time a local emergency is announced. This is especially true at night. Many people are such sound sleepers that the sound of sirens in the distance will not awaken them. Then, too, in many communities the siren is also used to summon volunteer firemen with the result that a large proportion of the population of these communities are not likely to attach any more significance to the sound of sirens than that volunteer firemen are being summoned. Hence, there is still a need for a community warning system which will reach into the home of every individual within the community and which will have special significance to the effect that a local or national emergency is at hand.

One approach to this problem of alerting all of the people in a community to a local or national emergency is to utilize the community electrical power system. This approach is feasible, and, indeed, has been suggested before, because there are few homes, if any, which do not have connections to the community electrical power system. The solutions to this problem which have been proposed and which are based on this approach are unsatisfactory, however, for a variety of reasons. A chief reason is that the devices used are too complicated and thus too expensive for community-wide acceptance. An other reason is the chance of failure of the devices proposed. Still another reason is that spurious interruptions of electrical current in community electrical power systems, which may be the result of natural causes such as lightning and the like, and the result of mechanical causes such as automatic relays and overload switches in the electrical system, actuate the warning devices to give false warnings frequently enough to make such devices unreliable.

A general object of this invention is to provide an Patented Mar. 8, 1965 emergency alarm system which can be placed in every house and building in a community and which is actuated by purposeful interruptions in the community electrical power system.

A specific object of this invention is to provide a warm ing system which is simple in operation and in structure.

Another specific object of this invention is to provide a home alarm device which will give warning of local and national emergencies and which need be merely plugged into a convenient electrical outlet in the home.

These and other objects which may appear as this specification proceeds are achieved by this invention which shall be described in the context of the drawings which form a material part of the disclosure. A brief listing of the drawings is as follows.

FIG. 1 is a perspective view of the outside of a preferred embodiment of the warning device of this invention.

FIG. 2 is a schematic diagram of the electrical circuitry involved in the preferred embodiment of the warning device of this invention.

FIG. 3 is a top perspective View of a portion of an alternative embodiment of this invention.

FIG. 4 is a circuit diagram of the alternative embodiment shown in FIG. 3.

The drawings broadly disclose an alarm actuating circuit which is operable merely upon the line cord thereof being plugged into a suitable wall socket connected to the community electrical power supply system. The heart of the unit is a switch responsive to a predetermined number, greater than one, of interruptions in the community electrical power supply for completing the circuit between an electrical power supply source and an electrically operated alarm. The power source may be batteries or the community electrical power supply. The alarm can be a bell, buzzer, light, radio and the like, even including sirens. Means are provided for resetting the switch in the event of spurious interruptions in the community power supply and in the event the emergency for which the alarm was given has ceased.

Interruption, as uesd in this application, means a decrease variation in the standard electrical power which can include cutting off the power entirely or substantially decreasing it to an amount necessary to cause the alarm device to operate in the desired manner.

Structure The drawings specifically disclose an alarm unit 10 comprising a housing or alarm box 11. Extending out from the alarm box 11 is a conventional two-wire electrical line cord 12 with plug. In addition there may be provided one or more two-wire electrical cables, such as cables 13 and 14, coupled as by Way of phone jacks and plugs to the electrical circuitry and components within the alarm box 11 and leading to various types of alarms. On an exposed face of the alarm box 11 there is provided a normally closed test switch 15 and an indicator light 17.

Within the box 11 there is provided an electrical switch component 18 and an automatic reset switch 19 (FIG. 2). There may also be included within the box 11 electrically operated alarm. means including battery powered alarm means. However, in the embodiment shown in the drawings, the alarm means are located externally of box 11. Also located within the box 11 are the various electrical leads and wiring for electrically connecting together the various components of the alarm system in the manner to be described in the paragraphs which follow.

The line cord 12 comprises a pair of electrical leads 20 and 21. Line cord lead 20 is connected to a first terminal of the test switch 15. The other line cord lead 21 is connected to a first end of a fuse 22.

The electrical switch component 18, which may be termed a step relay switch, comprises a rotatable switch arm 24 in combination with a relay solenoid 25 and a reset solenoid 26. The arm 24 is rotatable stepwise from one position or point to the next.

Preferably, it has a first position, a last position and a number of intermediate positions. These positions are indicated in the drawings by contacts 27, 28, 29, 30, 31, 32 and 33 with contact 27 being at the first position and contact 33 being at the last position. When current flow through the relay solenoid 25 is interrupted, the switch arm 24 moves from one contact to the next, proceeding stepwise with each current interruption from contact 27 to contact 33. However, when electrical current flows through the reset solenoid 26, the switch arm 24 returns to its first position at contact 27.

Contacts 28, 29 and 30, it will be observed, are electrically connected together by jumper wires 34 and 53. Moreover, contacts 31 and 32 are electrically connected together by a jumper wire 54.

Relay solenoid 25 has two terminals, the first one of which is connected by electrical lead 35 to the second terminal of the test switch 15, the second one of which is connected by electrical lead 36 to the second end of the fuse 22. Also connected as by electrical leads 37 and 38 to said first terminal of the relay solenoid 25 is the switch arm 24.

Reset solenoid 26 likewise has a first terminal and a second terminal. The first terminal thereof is connected as by way of electrical leads 39 and 40 to said second terminal of relay solenoid 25. The second terminal thereof is connected as by way of electrical lead 41 to the contact 33 of the electrical switch component 18.

The indicator light 17, preferably of the neon type, has a first and a second terminal, the first of which is connected by electrical lead 42 to the contact 27 and the second of which is connected as by electrical leads 43 and 40 to said second terminal of the relay solenoid 25.

The automatic reset switch 19 comprises a resistance type heater element 56, a variable resistor 57 and a normally open, heat sensitive switch arm 58 with a contact 59. One terminal of the heater element 56 is electrically connected to the switch arm 58 and as by an electrical lead 60 to contact 28 of the step relay switch component 18. The other terminal of the heater element 56 is electrically connected to one terminal of the variable resistor 57. The other terminal of the variable resistor 57 is electrically connected as by electrical leads 61, 39, 40 and 36 and the fuse 22 to the line cord lead 21. The contact 59 is electrically connected as by an electrical lead 62 to the second terminal of the reset solenoid 26. When current flows through the heater element 56, heat is generated, thereby causing the heat sensitive switch arm 58 to move towards its contact 59. When a predetermined temperature has been reached, which is a function of time, the switch arm 58 will touch the contact 59. By suitable adjustment of the variable resistor 57, the time involved for the switch arm 58 to strike the contact 59, once current starts to flow through the heater element 56, can be regulated.

The alarm cable 13 depicted in FIG. 1 extends to a 110 volt A.C. powered alarm. The cable 13 comprises a pair of electrical leads 46 and 47 (FIG. 2). The electrical lead 46 is connected via electrical lead 40 to said second terminal of the relay solenoid 25 while the electrical lead 47 is connected to the contact 31. Connected across these leads 46 and 47 outside of the box 11 (or inside of the box in other embodiments) may be a buzzer or bell 48, a light 49 and the like.

The alarm cable 14 depicted in FIG. 1 extends to a battery powered alarm, and includes a pair of electrical leads 50 and 47 (FIG. 2). The lead 47 of the alarm cable 14 is electrically common to the lead 47 of the alarm cable 13 because of the common connection to the contact 31 of the electrical switch component 18.

Hence, separate leads are not shown although in actual practice separate leads would be used. The lead 50 is electrically connected as by way of electrical lead 38 to the switch arm 24. Connected across the leads 47 and 50 outside of the box 11 (or inside of the box in other embodiments) is a battery powered alarm such as a battery and bell 51 in series, a battery and light 52 in series, and the like.

Operation To use the alarm unit 10, the same is placed at a convenient location and the line cord 12 plugged into any suitable electrical outlet associated with the community electrical power supply system, whereby the relay solenoid 25 is energized. At this point, if switch arm 24 happens to be on contact 27, the indictaor lamp 17 will light up. If switch arm 24 happens to be on contacts 28, 29 and 30, the reset switch 19 will be closed after a predetermined period of time has elapsed, causing the reset solenoid 26 to be energized and thereby causing switch arm 24 to be in contact with position contact 27, lighting the indicator lamp 17. In other words, when alarm unit 10 is plugged in, it will automatically reset itself to contact 27 by means of the time delay switch 19 if the arm 24 happens to be resting on contacts 28, 29, or 30.

If a volt A.C. powered alarm such as the bell 48, light 49 and the like is to be used, the alarm cable 13 therefrom is plugged into the appropriate jack in the box 11. If a battery powered alarm is to be used instead, the alarm cable 14 therefrom is plugged into the appropriate jack in the casing 11. Usually, the two types of alarms will not be used together. However, such can be done and for that reason both alarm cables 13 and 14 are shown plugged into the suitable jacks of the alarm unit 10 in FIG. 1. If the arm 24 happens to be on contacts 31 or 32 after the unit 10 is plugged in, then the alarms will sound. By pushing the test switch 15 one or more times, the switch arm 24 is advanced to its contact 33 at which point the reset solenoid 26 is energized. This causes arm 24 to return to its first position contact 27, thereby lighting indicator lamp 17. Thus, in any event, the warning system is now in operation.

When it is determined that a national or local emergency exists, the electrical utilities in the affected areas are notified as by direct telephone. Immediately, the power plant operators interrupt the power a predetermined number of times. In the embodiment shown, the predetermined number is four. However, this number may be more and less than four, but it will always be greater than one. Preferably, however, it is four or more because in many communities, the relay and overload mechanisms associated with the community power system may create in normal operation up to three momentary interruptions in electrical power to the community. Hence, five or more contact positions in the electrical switch component 18 are preferred wherefore the electrical power is preferably interrupted four or more times when it is desired to give warning of a national or local emergency.

With each interruption of the community electrical power supply, the relay solenoid 25 is de-energized and the switch arm 24 advances from one contact to the next. When, as in the case of the embodiment shown in the drawings, four momentary interruptions have occurred, the switch arm 24 will be in touch with its contact 31 whereby the electrical circuit of the 110 volt A.C. powered alarms 48 and 49 is completed. The audible and visual alarm is thereby given. The individual receiving the alarm can immediately head for shelter and turn on his radio to a local or Conelrad frequency for information as to the nature of the emergency. This entire procedure can take place within a matter of seconds.

When the national or local emergency ceases, or after any predetermined period of time, the power station operator again momentarily interrupts the electrical power to the community a predetermined number of times which, in the case of the embodiment shown in the drawings, is two. With each interruption, the relay solenoid 25 is de-energized, causing the switch arm 24 to advance from one contact to the next. In advancing from contact 32 to contact 33 the circuit of the 110 volt operated alarms 48 and 49 and the circuit of the battery operated alarms are broken. When the switch arm 24 touches the last contact 33, the circuit of relay solenoid 26 with the 110 volt, community power supply is completed and solenoid 26 is energized. The switch arm 24 thereupon is returned to its first contact position and into touch with its contact 27 whereupon the indicator light 17 commences to glow. The alarm unit is then ready for the giving of another alarm.

As already indicated, spurious interruptions in the power supply to the local comunity may occur. When such happens, the switch arm or armature 24 will, of course, move out of touch with its first contact 27 to the next contact 28, and possibly even from the contact 28 to contacts 29 and 30 depending upon the number and timing of the spurious interruptions. However, because the contacts 28, 29 and 30 are connected together by the jumper wires 53 and 34 and electrically connected to the reset switch 19 by the lead 60, the circuit of the heater element 56 is completed. After the predetermined period of time as established by the variable resistor 57 has elapsed, the reset switch arm 58 will close, causing the reset solenoid 26 to be energized and thus the switch arm 24 to be returned into position in touch with the first position contact 27. Thus, the alarm device is completely automatic and once plugged in will always maintain itself in its proper position. This is especially important in that without the automatic reset feature, it is conceivable that a power company might heve several spurious interruptions during the night, causing the switch arm 24 in all alarm units to advance to position 29 or 30. Then if an actual emergency were to arise before the public had a chance to reset their alarm units 10, the normal interruption procedure from the power company would carry arm 24 past the alarm actuating contacts 31 and 32, thus causing the device to be unable to give the necessary alarm.

The period of time or delay time in which the reset switch arm 58 closes is selected with the period of time needed to give an alarm with this invention in mind. The delay time should be at least slightly greater than the period of time needed by the power plant operator to interrupt the community power supply the prescribed number of times. Generally speaking, the delay time will be about fifteen to thirty seconds. With delay time selected, the variable resistor 57 is adjusted until the delay 0 time condition is met. This is a factory adjustment.

As can be seen, the number (n) of interruptions and the number (n+1) of positions through which the switch arm 24 must move before completing the 110 volt circuit or the battery circuit of the alarm means is selected according to the number of spurious interruptions as would likely occur between resettings. Generally speaking, the number (n+1) is greater than one. Preferably, the number (n) is four. However, it may be five and greater. In addition, the number m of contact positions from the n+1 contact position to the contact position at which the solenoid 26 circuit is completed can be any number. In the embodiment shown, it is two. Preferably, it is the last contact position of which the switch arm 24 is inherently capable of reaching. Hence, there may be more than one contact position for the switch arm 24 between the n+1 contact position at which the alarm electrical circuits are completed and the contact at which the reset solenoid 26 electrical circuit is completed. From the foregoing, it will be apparent that the switching position represented by contact 27 may aptly be termed an inactive or reset position, the switching positions represented by contacts 28, 29, and 30 may be termed active switching position preceding the alarm-actuating switching positions, the switching positions represented by contacts 31 and 32 may be termed the alarm-actuating positions, and the switching position represented by contact 33 may be termed an active switching position succeding the alarm-actuating positions.

It is contemplated that a spurious interruption in the community power system or in portions thereof may occur just before alarm is to be given and within the time delay period established by the time delay switch 19. Hence, as a saftey factor, the jumper wire 54 between contacts 31 and 32 of the embodiment of FIG. 2 is provided. In other embodiments, wherein more than two contact positions for the switch arm 24 are involved between the contact 31 and the like and the contact 33 and the like, the electrical lead 47 may be connected to more than one of these intermediate contacts. Hence, if the switch arm 24 prior to the giving of the emergency signal is resting on, for example, contact 28, and the power plant operator interrupts the community power supply the prescribed number of times, n, in this instance four, the switch arm 24 will still complete the electrical circuit of the 110 volt A.C. operated alarm and of the battery powered alarms as the case may be. By providing the contact for completing the circuit of the reset solenoid 26 at the end of the series of contact positions of the switch arm 24, when the emergency is over and the power plant operator interrupts the community power supply the prescribed number of times, m, for turning off the alarms and for resetting the alarm box, the switch arm 24 regardless of whether it be on the contact 31 or 32 will nevertheless come into contact with the last position contact 33, thereby energizing the reset solenoid 26 and returning the switch arm 24 to its first position contact 27.

A simplified embodiment of this invention is shown in FIGS. 3 and 4. Turning first to FIG. 4, the connection to the power line is once again shown as 20, 21. The test switch 15 is normally closed and, when opened, interrupts the current normally supplied to the coil 25 of switch 18. Switch 18 is shown in detail in FIG. 3 and consists basically of a block riding in a U-shaped track 102 and movable therein from left to right in the perspective of FIG. 3. A spring 104 biases block 100 to the left, but a pawl 106 engaging teeth 108 of block 100 prevents the block 100 from moving to the left. The coil 25 of the switch acts as a solenoid which holds the core 110 to the left when current is supplied to the coil 25. A spring 112 attached to the core 110 tries to pull the core 110 to the right, but is overpowered by coil 25 as long as current fiows through coil 25. The core 110 terminates in a pawl 114 which is biased in a downward direction in FIG. 3 by suitable biasing means (not shown). When the core 110 is withdrawn into the coil 25 as far as it will go, the edge 116 of pawl 114 rests on the surface of plate 118 as shown in FIG. 3 and is prevented thereby from engaging the teeth 120 of block 100. If the electric current through coil 25 is now cut off, the spring 112 pulls core 110, and with it pawl 114, to the right, until edge 116 of pawl 114 rides over the edge 122 of plate 118 and, being biased in a downward direction, drops down to engage the teeth 120 of block 100. After engaging the teeth 120, pawl 114 continues its travel to the right under the influence of spring 112 until it is prevented from further movement to the right by hitting edge 124 of plate 118.

The block 100 carries on its upper surface a contact strip 126 which is preferably convex so as to engage corresponding contact strips 128 mounted on the inside of the cover 130 of the device 10. The electrical connections to strips 126 and 128 areshown in FIG. 4, from which it will be readily apparent that strip 126 is in effect the movable contact of a multi-position switch 18, whereas contacts 128 are the fixed contacts of the same multi-position switch 18. (The cover 130 and strips 128 are shown in phantom lines in FIG. 3 so as not to obscure the remainder of the mechanism.) The size of the teeth 120 and the distance between the edges 122 and 124 of plate 118 are so designed that each time a power failure occurs, the pawl 114 will move block 100 to the right by exactly the distance between the centers of two adjacent contacts 128. Appropriate stops (not shown) are provided in channel 102 so that if block 100 is moved as far to the left in FIG. 3 as it will go, it is in such a position that when the cover 130 is affixed to the device 10, contact strip 126 will be in contact with contact strip 128a. The first power interruption will cause contact strip 126 to move into engagement with contact strip 12%; the second power interruption will cause it to move into contact with strip 1230, etc. In each instance, movement to the left of block 100 under the influence of spring 104 is prevented by pawl 106 engaging teeth 108 of the block 100. If less than 11 power interruptions occur, electric power will be supplied through wire 132 to the coil 134. The coil 134 is wrapped around the shank 136 of pawl 106. The shank 136 is made of bimetal strip, and the coil 134 is so designed that it will gradually heat up when traversed by current, so that when it is energized, it will cause the bimetal strip 136 to heat up and distort downwardly in FIG. 3, thus disengaging the pawl 106 from teeth 108. When the pawl 106 has become completely disengaged from teeth 108, spring 104 is free to return block 100 to its initial leftmost position where contact strip 126 is in contact with contact strip 128a on cover 130. Thus, it will be seen that the thermal latch 106, 134, 136, together with spring 104 performs the same function as the reset coil 26 of the embodiment of FIG. 2. An alarm buzzer 138 may also be provided for purposes of testing or for alarm purposes if the device is not connected to any outside alarm system. The output 46, 47, 50 of the device of FIG. 4 serves the same purpose as the output of like numbers of the circuit of FIG. 2.

In operation, successive power failures at short intervals will cause pawl 114 to engage teeth 120 of block 100 and move it to the right step by step so that contact strip 126 successively comes in contact with each of the contact strips 128. If a sufficient number of power failures occur before coil 134 has had time to heat the metal strip 136 sufficiently to cause pawl 106 to snap out of engagement with teeth 108, strip 126 will eventually come in contact with contact strip 128e and will cause the alarm to sound. At the same time, the circuit of coil 134 is cut and the device can no longer reset itself until further current interruptions cause the device to move to the final contact strip 128g at which the alarm is deenergized and power is returned to coil 134 so as to cause the devise to reset itself.

Thus, there is presented a simple and yet most effective and practical alarm system. Its inherent simplicity leads to speed in notifying the public of emergency situations. The alarm box is small, compact, and simple in structure. The alarm box, therefore, can be readily manufactured at economical prices. Hence, it should be possible for each home to have several alarm units.

The alarm actuating unit 10, once the line cord 12 is plugged into any suitable electrical outlet, is constantly on duty, day and night. There is nothing to adjust and no tubes to burn out. No maintenance is required. All that is needed is an occasional glance at the alarm box to make certain that the indicator light 17 is glowing.

A major advantage of the alarm system of this invention is that no periodic mass testing is needed. Each individual can test his own alarm boxes by merely pushing the test switch to interrupt the electrical power to the alarm box the prescribed number of times.

Still another major advantage is that the alarm box can be installed anywhere either indoors or out wherever community power is available. The system is the simplest yet devised for alerting motorists or pedestrians on the streets and highways who might not have their radios on or other indicating devices to alert them. Moreover,

the alarm box can be used to operate air raid sirens and other public alarm or indicator devices in any emergency.

These and other advantages will be apparent to those in the exercise of ordinary skill in the art upon reading the foregoing description. In addition, this invention may be embodied in several forms without departing from the spirit or essential characteristics thereof. Consequently, the embodiments just described are illustrative and not restrictive since the scope of the invention is defined by the appended claims rather than by the description preceding them.

I claim:

1. In a community alarm system responsive to a predetermined number of interruptions of the community power supply within a predetermined time, a movable member, a movable contact mounted on said movable member, biasing means biasing said movable member in said direction, latch means for preventing movement of said movable member in said first direction, advancing means engageable with said movable member and biased for movement in a second direction, electromechanical means connected to said community power supply for holding said advancing means out of engageemnt with said movable member when said community power supply is energized, a plurality of fixed contacts successively engageable by said movable contact upon movement of said movable member, limit means for limiting movement of said movable member by said advancing means to the distance between two of said fixed contacts each time said community power supply is deenergized, and time delay means operative to release said latch if less than said predetermined number of power interruption occur within said predetermined time.

2. An electrical alarm system for connection with a community power system for giving warning of local and national emergencies, which comprises: stepping switch means responsive to at least n interruption of electrical current in said power system, it being a predetermined number greater than 1, said switch means including movable arm means connected to the first side of said power system, said switch means further including contact positions from a first position to at least an n+1+m position, m being a predetermined whole number, alarm means connected to the n+1 position contact and to the second side of said power system, relay solenoid means connected across said power system for stepping said arm through the contact positions in response to interruptions of said electrical current, and reset means for automatically returning said arm to said first position from any of said n positions upon prolonged contact therewith.

3. An electrical alarm system for connection with a community power system for giving warning of local and national emergencies, which comprises: stepping switch means responsive to at least n interruptions of electrical current in said power system, It being a predetermined number greater than 1, said switch means including movable arm means connected to the first side of said power system and further including contact positions from a first position to at least an n+l+m position, m being a predetermined whole number, alarm means connected to the n+1 position contact and to the second side of said power system, relay solenoid means connected across said power system for stepping said arm through the contact positions in response to interruptions of said electrical current, a reset solenoid for returning said arm means to said first position, said reset solenoid having a first connection to said second side of said power source, a normally open thermal time delay switch connected in series with all of the n position contacts, said reset solenoid having a second connection to said time delay switch and to said n+1+m position contact whereby the movable arm isreset from the n+1+m position and from said it positions upon prolonged contact with any of the latter.

4. An electrical alarm system for connection with a community power system for giving warning of local and national emergencies, which comprises: stepping switch means responsive to at least 72 interruptions of electrical current in said power system, It being a predetermined number greater than 1, said switch means including movable arm means connected to the first side of said power system and further including contact positions from a first position to at least an n+1-l-m position, m being a predetermined whole number, alarm means connected to the w+l position contact and to the second side of said power system, relay solenoid means connected across said power system for stepping said arm through the contact positions in response to interruptions of said electrical current, a reset solenoid for returning said arm means to said first position, said reset solenoid having a first connection to said second side of said power source, a normally open thermal time delay switch connected in series with all of the n position contacts, said reset solenoid having a second connection to said time delay switch and to said rr-i-l-l-m position contact whereby the movable arm is reset from the n+1+m position and from said n positions upon prolonged contact with any of the latter, and indicator means connected between said first position contact and said second side of said power source for signaling the presence of said arm means at said first contact position.

5. An electrical alarm system for connection with a community power system for giving warning of local and national emergencies, which comprises: stepping switch means responsive to at least n interruptions of electrical current in said power system, 17 being a predetermined number greater than 1, said switch means including movable arm means and further including contact positions over which said arm means may move from a first position to at least an n+1+m position, 771 being a predetermined whole number, a self-contained source of electrical energy connected at a first side to the n+1 position contact of said switch means, electrically operated alarm means connected between the second side of said source and said movable arm means, relay solenoid means connected across said power system for stepping said arm through the said contact positions in response to interruptions of said electrical current, a reset solenoid having a first connection to said second side of said power system, a normally open thermal time delay switch connected in series with all of the 71 position contacts of said switch means, said reset solenoid having a second connection to the said time delay switch and to said n+1+m position contact whereby the movable arm is reset from the n+1+m position and from said it positions upon prolonged contact with the latter.

6. An electrical alarm system for connection with a community power system for giving warning of local and national emergencies, which comprises: stepping switch means responsive to at least it interruptions of electrical current in said power system, it being a predetermined number greater than 1, said switch means including movable arm means and further including contact positions over which said arm means may move from a first position to at least an 7z+l+m position, m being a predetermined whole number, a self-contained source of electrical energy connected at a first side to the n+1 position contact of said switch means, electrically operated alarm means connected between the second side of said source and said movable arm means, relay solenoid means connected across said power system for stepping said arm through the said contact positions in response to interruptions of said electrical current, a reset solenoid having a first connection to said second side of said power system, a normally open thermal time delay switch connected in series with all of the n position contacts of said switch means, said reset solenoid having a second connection to the said time delay switch and to said n+1+m position contact whereby the movable arm is reset from the n-l-l-I-m position and from said It positions upon prolonged contact with the latter, and indicator means connected betwen said first position contact and said second side of said power source for signaling the presence of said arm means at said first contact position.

7. An alarm system responsive to a predetermined number of successive interruptions of a community power supply, comprising: selector switch means having at least four successive switching positions, including an inactive rest position, at least two active switching positions and at least one alarm-actuating position; means connected to said community power supply for moving said selector switch means through the said successive switching positions in response to corresponding successive interruptions in said community power occurring in a predetermined time sequence; reset means for automatically returning said selector switch means to its said inactive rest position from any of said active switching positions which precede said alarm-actuating position of said community power supply remains energized longer than a predetermined time interval following one or more of said interruptions; said reset means including a normally open thermal time delay switch coupled to said power supply and having a time delay period slightly longer than said predetermined time sequence of power interruptions; and said reset means further operating through a direct electrical connection with any of said active switching positions which succeed said alarm-actuating position to effect automatic and undelayed return of said selector switch means to its said inactive rest position from any of such succeeding active switching positions.

References Cited by the Examiner UNITED STATES PATENTS 1,356,626 10/1920 Hulit 340-157 1,710,126 4/1929 Vaughan etal. 340 157 1,920,806 8/1933 Rich 340167 2,094,733 10/1937 Byrnes 340164 2,811,712 10/1957 Saunders 340 310 X 2,912,676 11/1959 Canto 61:31. 340164 FOREIGN PATENTS 257,937 11/1927 Great Britain.

519,688 4/1940 Great Britain.

351,523 8/1937 Italy.

360,084 6/1938 Italy.

NEIL C. READ, Primary Examiner.

ELI I. SAX, IRVING L. SRAGOW, Examiners.

Claims (1)

1. IN A COMMUNITY ALARM SYSTEM RESPONSIVE TO A PREDETERMINED NUMBER OF INTERRUPTIONS OF THE COMMUNITY POWER SUPPLY WITHIN A PREDETERMINED TIME, A MOVABLE MEMBER, A MOVABLE CONTACT MOUNTED ON SAID MOVABLE MEMBER, BIASING MEANS BIASING SAID MOVABLE MEMBER IN SAID DIRECTION, LATCH MEANS FOR PREVENTING MOVEMENT OF SAID MOVABLE MEMBER IN SAID FIRST DIRECTION, ADVANCING MEANS ENGAGEABLE WITH SAID MOVABLE MEMBER AND BIASED FOR MOVEMENT IN A SECOND DIRECTION, ELECTROMECHANICAL MEANS CONNECTED TO SAID COMMUNITY POWER SUPPLY FOR HOLDING SAID ADVANCING MEANS OUT OF ENGAGEMENT WITH SAID MOVABLE MEMBER WHEN SAID COMMUNITY POWER SUPPLY IS ENERGIZED, A PLURALITY OF FIXED CONTACTS SUCCESSIVELY ENGAGEABLE BY SAID MOVABLE CONTACT UPON MOVEMENT OF SAID MOVABLE MEMBER, LIMIT MEANS FOR LIMITING MOVEMENT OF SAID MOVABLE MEMBER BY SAID ADVANCING MEANS TO THE DISTANCE BETWEEN TWO OF SAID FIXED CONTACTS EACH TIME SAID COMMUNITY POWER SUPPLY IS DEENERGIZED, AND TIME DELAY MEANS OPERATIVE TO RELEASE SAID LATCH IF LESS THAN SAID PREDETERMINED NUMBER OF POWER INTERRUPTION OCCUR WITHIN SAID PREDETERMINED TIME.

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