US3636542A - Portable photoresponsive intrusion alarm - Google Patents

Abstract

An intrusion alarm with a self-contained power source having a trigger circuit with means for adjusting its standby level and means receiving available ambient light which when blocked causes the circuit level to rise and provide a triggering signal. An alarm signal circuit with a gated semiconductor is energized by the trigger signal provided to the gate of the semiconductor. The intrusion alarm may be modified for connection to an outside source and may be provided with a remotely positioned signal generator.

Description

United States Patent Apple 1 1 Jan. 18, 1972 [54] PORTABLE PHOTORESPONSIVE INTRUSION ALARM [72] Inventor: Joseph H. Apple, Alexandria, Va.

[73] Assignee: AMF Incorporated [22] Filed: Oct. 15, 1969 [21] Appl. No.1 866,649

[52] 11.5. CI. ..340/258 B, 340/258 D, 340/276, 340/228 5 [51] Int. Cl. ..G08b 13/18 [5%] Field 01 Search .340/258, 258 B, 258 D, 296, 340/228 S, 283; 250/221 [56] References Cited UNITED STATES PATENTS 3,536,923 10/1970 Tellerman ..340/258 X 3,555,532 1/1971 White et al. .340/228 S X 3,560,950 2/1971 Peters ..340/258 3,011,163 11/1961 Britt ..340/274 3,041,592 6/1962 Schmidt ..340/276 3,226,705 12/1965 Kaufman et a]... ..340/276 X 3,234,535 2/1966 Schordine ....340/276 X 3,284,787 11/1966 Voig et al... ....340/276 UX 3,329,946 7/1967 Robbins ..340/258 3,390,388 6/1968 Kahl, Jr. et al. ....340/258 3,498,047 3/1970 McLeod et al ..250/221 X Primary ExaminerDonald J. Yusko Assistant ExaminerMichael Slobasky Attorney-George W. Price and Charles .1. Worth [57] ABSTRACT An intrusion alarm with a self-contained power source having a trigger circuit with means for adjusting its standby level and means receiving available ambient light which when blocked causes the circuit level to rise and provide a triggering signal. An alarm signal circuit with a gated semiconductor is energized by the trigger signal provided to the gate of the semiconductor. The intrusion alarm may be modified for connection to an outside source and may be provided with a remotely positioned signal generator.

12 Claims, 5 Drawing Figures PATENTEU JAN 8 9 2SWEET 1UF 2 FIG.2

INVENTOR. JOSFPH H. APPLE BY 2 2 g AGE/V7 PATENIED Jun 8 I72 31636542 SHEET 2 0r 2 3i FIG. 3

FIG. 4

Hi'gi 0 48 49 N I.\'Vl-..'\"1'f)k. JOSEPH H. 4/27 5 AGENT PORTABLE lPI'IOTORESPONSIVE INTRUSION ALARM This invention relates generally to protective devices and more particularly to intrusion alarms.

There are available many alarm or break-in devices which vary from expensive sophisticated systems to simple mechanical devices to be mounted on a door jamb and triggered by unauthorized opening of the door. For the most part, these protective devices are fixed installations which are periodically set for operation and deactivated during interim periods. Others of these devices may be set up, when required, in any room of a building where a source of power is readily available.

An object of the present invention is to provide a portable photoresponsive protective device with a self-contained power source.

Another object of the present invention is to provide the foregoing device having means for adjusting the standby level of the circuit for the available light in the area the alarm is to be used.

And another object of the present invention is to provide the foregoing device which is easily set for operation and relies on the shock effect of a sudden loud persistent signal in a relatively dark and quiet environment to scare away an intruder.

Still another object of the present invention is to provide the foregoing device which is relatively simple and inexpensive to manufacture, is of a rugged and reliable construction, and is easily set up for use.

And still another object of the present invention is to provide the foregoing device with a remotely located signal generator.

The foregoing and other objects and advantages will appear more fully hereinafter from a consideration of the detailed description which follows, taken together with the accompanying drawing wherein several embodiments of the invention are illustrated by way of example. It is to be expressly understood, however, that the drawings are for illustration purposes only and are not to be construed as defining the limits of the invention.

FIG. 1 is an elevational view, with the cover removed to show the internal operating parts, of an intrusion alarm made in accordance with the present invention.

FIG. 2 is a circuit diagram of the novel device of FIG. 1.

FIGS. 3, 4 and 5 are circuit diagrams of various modifications of the novel device for providing signal generating means remotely located therefrom.

Referring now to the drawings, a case is provided with asidewall 11, and afront wall 12 and arear wall 13 extending from opposite edges of the sidewall. Atop wall 14 and aremovable bottom wall 15 extend from thesidewall 11 between the front andrear walls 12 and 13, and aninternal wall 16 is provided in spaced substantially parallel relationship between the top and bottom walls thereby dividing the area within thecase 10 into acircuit chamber 17 and abattery chamber 18 which normally are closed by the cover of the case that has been removed in the drawings. Thesidewall 11 and the cover (not shown) are formed to provide tracks to permit thebottom wall 15 to be slid away from thefront wall 12 and thereby open as an access into thebattery chamber 18.

Ameter 20 extends through and is connected to thetop wall 12. Acontrol 21 to set the novel device is mounted on therear wall 13 and has anexternal knob 22 for operation. An externally operated on/olf switch 23 also is mounted on therear wall 13 and connects a signal generator means 24 to one side of a self-contained low level DC power source, in this instance, batteries B in thechamber 18. The signal generator means 24, which in this instance is a horn to provide an audible signal, is mounted in thechamber 17 to thesidewall 11 which is provided with a plurality ofsmall openings 25 forming a grillwork so the audible signal is not muffled.

Thefront wall 12 is provided with an opening orwindow 26 for passage of light to a light-responsive element orphotocell 27 which is mounted on a printedcircuit board 28 in the front end of thecircuit chamber 17. The printedcircuit board 28 is supported in slots in the upper andinternal walls 14 and I6, and mounts atransistor 40, anadjustable resistance 41,resistors 42 and 46, adiode 43 and an S.C.R. 44 in addition to the photocell 27 (see FIG. 2).

The usual types ofbattery contacts 31 and 32 are supported by the front andrear walls 13 and 12, respectively, at opposite ends of thebattery chamber 18. Thecontact 31 is provided with awire conductor 33 which extends through an opening 35 in the rear end of thewall 16 and is connected to the main or set"control 21. Similarly, thecontact 32 is provided with awire conductor 34 which extends through anopening 36 in the front end ofwall 16 and is connected to the circuit provided by theboard 28. Aharness 29 or plurality of wire conductors are provided in thechamber 17 to conductively connect themeter 20,control 21,switch 23 and horn orsignal generator 24 to the circuit of theboard 28.

Referring now to FIG. 2, the main or set"control 21 is comprised of an on/offswitch 37, connected on one side to thebattery contact 31 by thewire conductor 33, and a variable resistance orpotentiometer 39. The other side ofswitch 37 is connected to one side ofswitch 23 which is connected to the horn or signal generating means 24. Thevariable resistance 39 connectsline 38 to the base oftransistor 40 and to one side of thephotocell 27 which is connected on the other side to thewire conductor 34. Therefore, the variable resistance orpotentiometer 39 and thephotocell 27 form a resistance voltage divider which is manually adjustable and light-responsive to control the base bias oftransistor 40.

Thewire conductor 34, which is connected to one side of thephotocell 27, is connected to the cathode of the S.C.R. 44 which is anode connected by aconductor 45 to thehorn 24. Aresistance 46 is provided to also connect theconductor 34 to the emitter oftransistor 40 and gate of S.C.R. 44. Anadjustable resistance 41 connects theline 38 to the collector of thetransistor 40 and to one side of themeter 20 which is connected on the other side to theline 38 by theresistance 42. Adiode 43 is connected across the resistance connections of themeter 20 to prevent meter damage. The adjustability ofresistance 41 is to provide a resistance equal to theresistance 42 and the internal resistance of themeter 20.

In operation, withswitches 23 and 37 open, thecase 10 is positioned to face a source of light which passes through the opening 26 in thefront wall 12 and impinges upon thephotocell 27 establishing its standby resistance or resistance level in the circuit. Theknob 22 is pulled out or away from thecase 10 connecting battery current to openswitch 23, to one side of themeter 20 acrossresistance 42, to the other side of the meter and the collector of thetransistor 40, and to thepotentiometer 39. Theknob 22 is then rotated to position the wiper of thepotentiometer 39 to provide the required bias to the base of thetransistor 40 so the level of conduction of the transistor establishes the proper collector current as is indicated on themeter 20. The emitter voltage oftransistor 40 provided to the gate of the S.C.R. 44 is below the value required to fire the S.C.R.

The alarm is now conditioned to be set for operation, and theswitch 23 is closed to connect one side of the battery B to the horn oraudible signal generator 24 which is unoperated or open-circuited because the S.C.R. 44 is not conducting. The novel alarm is now fully set for operation and will remain so, unless triggered, until it is shut off by pushingknob 22 inwardly to reopenswitch 39 and/or byopening switch 23.

When the alarm is set, an intruder interrupting the light which was passing through the opening 26 in thefront wall 12 and impinging on thephotoresponsive element 27 causes the resistance of the photoresponsive element to increase. This change in the resistance voltage divider, formed by theelement 27 and the potentiometer orvariable resistance 39 causes the bias of the base of thetransistor 40 to increase. The increased base bias results in higher collector current, which increases the reading ofmeter 20, and higher emitter voltage which now provides an adequate gate signal and fires the S.C.R. 44.

With the S.C.R. 44 conducting, thehorn 24 is connected by a closed circuit across the battery B and is, thereby, energized to generate an audible signal which will continue as long as electrical power is available, or until one or bothswitches 23 and 37 are opened.

The novel alarm may be modified in various ways without departing from the spirit and scope of the present invention. For example, while it is preferable to use batteries to provide a self-contained DC power supply, for extended continuous use an external AC to DC converter may be connected to thebattery terminals 31 and 32.

In some instances it may be desirable to provide a signal remote from the device. To accomplish this, the intrusion alarm is provided with a receptacle orsocket 47 in place of or conductively connected in parallel with thesignal generator 24.

As shown in FIG. 3, one side of thesocket 47 is connected to theswitch 23 and the other is connected to theconductor 45. The leads 51 of a remotely positioned signal generator means 50 are plugged into thesocket 47. Thus, the remote signal generator means 50 will be energized to provide an audible and/or a visible signal when the S.C.R. 44 starts to conduct. Arelay 48, of any suitable type may be used to control the remote signal generator means 50.

As shown in FIG. 4, therelay 48 is connected between theswitch 23 and theconductor 45 while the normally open contacts are provided in one of the connections to thesocket 47. When the S.C.R. 44 starts to conduct, therelay contacts 49 close and theremote signal generator 50 is energized.

Alternatively, theremote signal generator 50 may be con nected to a separate power source; either AC or DC. As shown in FIG. 5, one of theleads 51 is connected to aseparate power source 52. While therelay 48 is still connected between theswitch 23 and theconductor 45, therelay contacts 49 are each connected to a different one of the terminals of thesocket 47. When the S.C.R. 44 starts to conduct, therelay 48 will close and conductively connects itscontacts 49 to each other. This provides current to theremote signal generator 50 from the second orseparate power source 52.

In essence, the circuitry of an intrusion alarm made in accordance with the present invention is comprised of a trigger circuit, a signal circuit, ameter 20, and amain switch 37 provided by the set"control 21 providing power when closed to the two circuits and the meter. The trigger circuit comprises the triggersignal output transistor 40 and a voltage divider bias loop formed by thepotentiometer 39, which is adjustable to establish the standby level of the trigger circuit, and thephotocell 27, which causes the trigger circuit to provide an output signal in response to a reduction of light after the standby level of the trigger circuit has been set. The signal circuit includes the signal generating means, is manually connected and disconnected from the DC power source, and is controlled by the S.C.R. 44. The signal generating means may be theaudible signal generator 24 and/or theremote signal generator 50.

Although several embodiments of the invention have been illustrated and described in detail, it is to be expressly understood that the invention is not limited thereto. Various changes may also be made in the design and arrangement of the parts without departing from the spirit and scope of the invention as the same will now be understood by those skilled in the art.

I claim:

1. In a portable intrusion alarm, the combination comprismg:

a hollow case with a window at one end for passing available external ambient light therethrough, having a self-contained DC power source therein and a movable wall portion providing access to said DC power source;

a signal circuit within said case and connected on one side to said DC power source, including means when energized for generating an alarm signal and a gated semiconductor which when triggered to conduct causes said signal generating means to be energized;

a trigger circuit within said case and connected on one side to said DC power source, including an output transistor connected to the gate of said semiconductor and a voltage divider connected to said transistor and providing a bias thereto;

said transistor when biased above a standby level providing a gate signal triggering said semiconductor;

said voltage divider including manual means for adjusting the bias to said transistor to a standby level for the amount of available external light passing through said window and photoresponsive means adjacent said window causing the bias to said transistor to increase above such a standby level when at least part of the available external light is blocked from said window; and

switch means connected to the other side of each of said circuits and said DC power source, and establishing both of said circuits when closed.

2. The intrusion alarm in accordance with claim I, wherein:

a meter is connected to said trigger circuit providing a visual indication of the level of the bias to said transistor.

3. The intrusion alarm in accordance with claim I, wherein:

said switch means is a manual switch device operable between an open position and a closed position;

said manual means of said voltage divider is a variable resistance device;

said manual switch and variable resistance device being fixedly mounted within said case and having a common operating means extending outwardly through said case.

4. The intrusion alarm in accordance with claim 3, wherein:

said common operating means is movable axially to operate one of said devices and is rotatable to operate the other.

5. The intrusion alarm in accordance with claim 3, wherein:

said switch means further includes a manually operable on/off switch circuit connected between said manual switch device and said signal generating means, and when off disabling only said signal generating means when said manual switch device is closed.

6. The intrusion alarm in accordance with claim I, wherein:

said alarm signal generating means generates an audible signal and is fixedly mounted inside said case; and

said case having a plurality of openings therethrough in the immediate vicinity of said signal generating means thereby minimizing mufl'ling of the audible signal by said case.

7. The intrusion alarm in accordance with claim I, and said alarm signal generating means comprising:

a receptacle fixedly mounted in said case and having a pair of terminals open to the outside thereof;

one of said pair of terminals being connected to said semiconductor and the other being connected to said switch means;

a signal generator to be positioned remote from said case and having a pair of conductors extending therefrom and insertable into said receptacle each conductively engaging a difierent one of said terminals.

8. The intrusion alarm in accordance with claim 7, wherein:

said alarm signal generating means further includes an audible signal generator circuit connected in parallel with said terminals between said switch means and said semiconductor;

said audible signal generator being fixedly mounted within said case; and

said case having a plurality of openings therethrough in the immediate vicinity of said audible signal generator thereby minimizing the muffling of the audible signals generated.

9. The intrusion alarm in accordance with claim 7, and said alarm signal generating means further comprising:

relay means connected between said semiconductor and said switch means; and

said relay means providing normally open contacts in the connection to one of said terminals and causing said contacts to close when said semiconductor is triggered to conduct.

10. The intrusion alarm in accordance with claim 9, wherein:

said alarm signal generating means further includes an audible signal generator circuit connected in parallel with said relay between said switch means and said semiconductor;

said audible signal generator being fixedly mounted within said case; and

said case having a plurality of openings therethrough in the immediate vicinity of said audible signal generator thereby minimizing the muffling of the audible signals generated.

11. The intrusion alarm in accordance withclaim 1, and

said alarm signal generating means comprising:

a receptacle fixedly mounted in said case and having a pair of tenninals open to the outside thereof;

relay means connected between said semiconductor and said switch means;

said relay means providing normally open contacts each connected to a different one of said terminals and causing said contacts to close when said semiconductor is triggered to conduct;

a signal generator to be positioned remote from said case and having a pair of conductors extending therefrom of which one is insertable into said receptacle to conductively engage one of said terminals and the other is adapted for connection to a separate electrical power source; and

another conductor insertable at one end into said receptacle to conductively engage the other of said terminals and adapted at its other end for connection to the separate electrical power source.

12. The intrusion alarm in accordance with claim ll,

wherein:

said alarm signal generating means further includes an audible signal generator circuit connected in parallel with said relay between said switch means and said semiconductor;

said audible signal generator being fixedly mounted within said case; and

said case having a plurality of openings therethrough in the immediate vicinity of said audible signal generator thereby minimizing the muffling of the audible signals generated.

Claims (12)

1. In a portable intrusion alarm, the combination comprising: a hollow case with a window at one end for passing available external ambient light therethrough, having a self-contained DC power source therein and a movable wall portion providing access to said DC power source; a signal circuit within said case and connected on one side to said DC power source, including means when energized for generating an alarm signal and a gated semiconductor which when triggered to conduct causes said signal generating means to be energized; a trigger circuit within said case and connected on one side to said DC power source, including an output transistor connected to the gate of said semiconductor and a voltage divider connected to said transistor and providing a bias thereto; said transistor when biased above a standby level providing a gate signal triggering said semiconductor; said voltage divider including manual means for adjusting the bias to said transistor to a standby level for the amount of available external light passing through said window and photoresponsive means adjacent said window causing the bias to said transistor to increase above such a standby level when at least part of the available external light is blocked from said window; and switch means connected to the other side of each of said circuits and said DC power source, and establishing both of said circuits when closed.

2. The intrusion alarm in accordance with claim 1, wherein: a meter is connected to said trigger circuit providing a visual indication of the level of the bias to said transistor.

3. The intrusion alarm in accordance with claim 1, wherein: said switch means is a manual switch device operable between an open position and a closed position; said manual means of said voltage divider is a variable resistance device; said manual switch and variable resistance device being fixedly mounted within said case and having a common operating means extending outwardly through said case.

4. The intrusion alarm in accordance with claim 3, wherein: said common operating means is movable axially to operate one of said devices and is rotatable to operate the other.

5. The intrusion alarm in accordance with claim 3, wherein: said switch means further includes a manually operable on/off switch circuit connected between said manual switch device and said signal generating means, and when off disabling only said signal generating means when said manual switch device is closed.

6. The intrusion alarm in accordance with claim 1, wherein: said alarm signal generating means generates an audible signal and is fixedly mounted inside said case; and said case having a plurality of openings therethrough in the immediate vicinity of said signal generating means thereby minimizing muffling of the audible signal by said case.

7. The intrusion alarm in accordance with claim 1, and said alarm signal generating means comprising: a receptacle fixedly mounted in said case and having a pair of terminals open to the outside thereof; one of said pair of terminals being connected to said semiconductor and the other being connected to said switch means; a signal generator to be positioned remote from said case and having a pair of conductors extending therefrom and insertable into said receptacle each conductively engaging a different one of said terminals.

8. The intrusion alarm in accordance with claim 7, wherein: said alarm signal generating means further includes an audible signal generator circuit connected in parallel with said terminals between said switch means and said semiconductor; said audible signal generator being fixedly mounted within said case; and said case having a plurality of openings therethrough in the immediate vicinity of said audible signal generator thereby minimizing the muffling of the audible signals generated.

9. The intrusion alarm in accordance with claim 7, and said alarm signal generating means further comprising: relay means connected between said semiconductor and said switch means; and said relay means providing normally open contacts in the connection to one of said terminals and causing said contacts to close when said semiconductor is triggered to conduct.

10. The intrusion alarm in accordance with claim 9, wherein: said alarm signal generating means further includes an audible signal generator circuit connected in parallel with said relay between said switch means and said semiconductor; said audible signal generator being fixedly mounted within said case; and said case having a plurality of openings therethrough in the immediate vicinity of said audible signal generator thereby minimizing the muffling of the audible signals generated.

11. The intrusion alarm in accordance with claim 1, and said alarm signal generating means comprising: a receptacle fixedly mounted in said case and having a pair of terminals open to the outside thereof; relay means connected between said semiconductor and said switch means; said relay means providing normally open contacts each connected to a different one of said terminals and causing said contacts to close when said semiconductor is triggered to conduct; a signal generator to be positioned remote from said case and having a pair of conductors extending therefrom of which one is insertable into said receptacle to conductively engage one of said terminals and the other is adapted for connection to a separate electrical power source; and another conductor insertable at one end into said receptacle to conductively engage the other of said terminals and adapted at its other end for connection to the separate electrical power source.

12. The intrusion alarm in accordance with claim 11, wherein: said alarm signal generating means further includes an audible signal generator circuit connected in parallel with said relay between said switch means and said semiconductor; said audible signal generator being fixedly mounted within said case; and said case having a plurality of openings therethrough in the immediate vicinity of said audible signal generator thereby minimizing the muffling of the audible signals generated.

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