US3207850A - Alarm system with personally concealable radio-frequency transmitter - Google Patents

Description

D. s. FOREMAN 3,207,850 ALARM SYSTEM WITH PERSONALLY CONCEALABLE RADIO-FREQUENCY TRANSMITTER Filed Oct. 25, 1962 Sept. 21, 1965 OSCILLATOR MODULATOR TRANSMITTER L2 L L! BATTERY E BATTERY E BATTERY DETECTOR DISCRIMINATOR AMPLIFIER B PHONE- LINE PHONE-STATION MESSAGE ACTIVATOR SELECTER PLAYER C TELEPHONE LINES FIE.1

INVENTOR.

DAVIS SIDNEY REMAN AGENT often is not in a position to signal the alarm.

United States Patent 3,267,850 ALARM SYSTEM WITH PERSONALLY CONCEAL- ABLE RADiO-FREQUENCY TRANSMITTER Davis Sidney Foreman, RED. 2, Ahele Park, Putnam Valley, N.Y. Filed Oct. 23, 1962, Ser. No. 232,413 1 Claim. (Cl. 1795) This invention relates to alarm systems and more particularly to holdup or armed robbery alarm systems wherein the alarm is reported by telephone to a central oifice from which assistance or interception forces are dis patched,

Prior inventors have described alarm systems of varying complexity that are connected to burglary or fire sensing systems and which, when actuated, summon the telephone operator, relay a prerecorded message indicating the type of trouble and the exact location where assistance is required.

The prior art devices were and are physically connected to the power supply and telephone system of the protected premises. Both the trouble-sensing and the alarm- "transmitting systems may therefore be easily rendered tected premises may be easily isolated.

Further in cases of armed robbery or holdup the victim In cases where the alarm system consists of fixed buttons, treadles or similar signaling devices, criminals knowing the position of such signaling devices, take the precaution of restricting the movements of the victim in sensitive areas in order to prevent actuation of such fixed-position signaling devices.

It has also been proposed to use ultrasonic generators directly connected to remotely located alarm sensing devices for activating centrally located automatic alarm systems. Such systems possess major shortcomings as holdup alarms. In order to generate a signal audible to the sensing system of a distantly located automatic alarm, considerable power must be expended and due to the basic acoustic properties of ultrasonic signals, damping and baffiing effects limit the distance and direction at which such signals can be detected.

It is an object of this invention to provide an alarm system having an alarm-signaling unit independent of external power supplies and which upon actuation can transmit the alarm to an automatic alarm receiver and disseminator located at some distance from the premises being protected.

It is another object of this invention to provide an alarm system whereby the alarm signaling unit transmits its information in such a manner that natural phenomena such as lightning or man-made phenomena such as stray radio waves cannot generate spurious alarms.

It is a further object of this invention to provide alarm systems which are capable of generating several different alarms such as holdup, burglary, fire or medical emergency, and can send the proper prerecorded alerting message to the central dispatching station.

Other objects of this invention include the provision of omni-directional alarm-signal generators that can be secreted on the person of the possible victim for unobstrusive alarm signaling, alarm signal receiver/disseminators responsive to said generated signal which can automatically activate the telephone line, initiate a dialing sequence and will start an intelligence-imparting sequence when the telephone circuits are completed and the telephone line is answered by an assistance dispatching agency.

3,207,850 Patented Sept. 21, 1965 Other objects and advantages will be apparent from the description and drawings and the appended claim in which the invention in its several aspects is set forth.

FIG. I is a schematic diagram showing the entire alarm .system of the present invention.

This invention, according to its major aspects, contemplates the use of small battery-powered radio transmitter which is carried or otherwise disposed upon the person of a probable victim and which, upon activation, will generate a characteristic or coded radio signal. This signal is detected by a radio receiver tuned to this characteristic or coded signal. The receiver may be located at a considerable distance from the transmitter and is provided with power and telephone lines independent from the power lines and phone lines of the premises where the transmitter is located. The receiver will, automatically upon receipt of the signal, establish telephone communication either with the telephone company for alerting enforcement agencies or directly with the police or the law enforcement agencies and will start playing a prerecorded message over the telephone lines stating the need for assistance, type of assistance required, and location where the assistance is needed.

From the objects and statements of invention, it will be seen that this invention is directed to a general purpose alarm system wherein a radio alarm signal is generated at one location and received at another location from which it is automatically disseminated 'by telephone to institute a train of aid-summoning activities.

The invention will best be understood. by refernece to the drawings where FIG. I shows, by block diagrams, the general components of the alarm system where A is the alarm activator/transmitter unit consisting of an alarm switch 11, an oscillator circuit 12, a modulating circuit 13, for the oscillator and a transmitter 14, fitted with suitable antenna 15. The oscillator circuits 12, modulating circuits 13, and transmitter 14, are all powered by battery 16. In order that minimum drain be put upon the battery, it is preferred that the above electronic circuits be based on transistors and similar semiconductors including tunnel diodes. Such circuits are well-known to the art but are only incidental to the invention since circuits based on tubes are also operative. The latter circuits may require larger batteries which would make the unit more conspicuous and less portable.

The modulating circuits 13 are designed to modulate the basic signal of the oscillator either with an audio frequency to provide musical notes or cords or the signal from the oscillator 12 may be characteristically pulsed by modulating circuit 13 or it may be both tone and pulse modulated. The modulated signal is then transmitted by the transmitter and an antenna 15 either via amplitude modulation or frequency modulation. The latter is preferred since random electrical noises or static have the least effect on such signals. It is preferred to transmit the alarm signal at frequencies in the range above one magacycle (mc.).

At such frequencies only relatively low power is required to radiate signals sufiicient to span the distance from an endangered premise wherein the transmitter is located to preferred locations for the receiver/disseminator unit described below. Another advantage for transmitting at the frequencies above one me. and preferably between 200 and 500 me. is that at such frequencies the transmitters radiate from the resonant elements themselves which serve as antenna 15, thereby avoiding large, elaborate and visible antennae. One such commercially available transistorized transmitter unit, generating a tone-modulated and pulsed signal is small enough to be contained, together with its battery power supply within a conventional cigarette pack. Such miniature oscillating, modulating, and transmitting circuit combinations are described in detail in reference books on telemetry systems including Telemetry Systems by Mayo, Wells and Borden, and also The Air Forces Telemetry and Transducer Handbook and its supplement.

In FIG. 1, B represents the receiver/ discriminator unit having detector circuits 21, demodulating, filtering and discriminating circuits 22, and an amplifier 23.

The detector is tuned to receive the transmitted radiowave signal generated by activator/transmitter and the discriminator circuits are designed to identify the characteristic radiowave form of such signal and to filter out all others. The proper signal is then amplified to initiate operation of the disseminator C.

The disseminator unit C consists of mechanical and electronic units including a phone-line activator 31, a phone-station selector 32, message player 33 of similar device for indicating the type of alarm and the location requiring assistance.

Receiver B, since it is continually on a standby basis is preferably powered by the conventional power lines 34, but it can be powered by rechargeable batteries. The disseminator C similarly receives its power via the power lines and transmits the desired information via a conventional telephone circuit D.

The electronic circuits in receiver/discriminator unit B for detecting the :alarm signal from transmitter A, discriminating and identifying it from spurious signals and static, and amplifying the signal to operative levels for the components of unit C utilize the various conventional electronic circuits intended for such purposes. Such circuits are well-known in the art. The specific features of such circuits form no part of this invention beyond functioning in their intended capacity as detecting, discriminating and amplifying means.

The telephone line-activator element of this invention may be either external to the telephone circuit or with the permission of the telephone company, directly connected into the circuits leased from the telephone company. Such directly connected devices will be referred to hereinafter as internal devices.

When the line-activator is external to the telephone circuits it may operate by releasing the spring-loaded disconnect-switch on which the telephone hand-piece normally rests when the line is inactive. Releasing this button activatesthe line and permits the dialing mechanism at the telephone central ofiice to become engaged in the circuit and dailing may then commence. Such external line-activators may be operated by spring-powered latches released by solenoids or motors in response to the signal from the amplifier 23. Such external phoneline activators are disclosed in many previous patents including U.S. 2,478,514 wherein the hand-piece is lifted by a spring-actuated cradle and thereby removing the weight from the cradle-switch and establishing the circuit. U.S. Patent 2,878,315 discloses a device where the depressed switch-plunger is released by a motor driven arm. U.S. Patents 2,371,051, 2,811.584, and 2,866,850 disclose the release of the depressed switch by solenoidactuated arms.

Internal telephone circuit-activators include mechanical or electronic switches for completing the telephone circuit in response to the signal from the amplifier 23. Such internal telephone circuit activators, since they may be connected in the phone circuits only with he permission of the phone company, may take advantage of all of the special emergency-alerting circuits utilized by the telephone companies. These include specially modulated ringing circuits that activate automatic-switching devices and provide direct connection to central emergency headquarters. Such priority circuits are described or mentioned as parts of U.S. Patents #2,'919,307 and #2,923,772. A multi-purpose central office discriminator system is embodied in the disclosure of U.S.

2,831,178 which affords special priority to alarm systems in conjunction with telephone systems.

The phone-station selector device 32 can be any of the many external dialing devices. Many of these consist of releases for the detents or latches which hold pre-positioned spring-tensioned telephone dialing mechanisms. Upon release, the dial returns to the normal position thereby dialing the operator. Several such devices have been described in the art in U.S. Patents 2,371,051, 2,811,584, and 2,878,315.

Other external dialing devices are based on precoded mechanical means for turning the dial in proper sequence or rapidly making and breaking the telephone circuit by pressing and releasing the cradle-switch in simulation of the dialing pulses. Such devices are known to the art and are exemplified and described in detail in U.S. Patents 2,161,525, 2,478,514, 2,830,119 and 2,952,740.

Further, by renting some of the newer types of card dialing telephones from the telephone company once the dialing sequence is initiated. The card in the mechanism determines the party to be summoned. Such auto matic dialing of specific numbers is especially valuable where medical aid or private patrol agencies are to be summoned by the alarm system of this invention or where special numbers are required for summoning the police or the authorities. 1

Internal dialing devices are legion and includes in addition to the card dialing phone mentioned above a host of devices that are connected to the telephone circuit to dial special numbers by simulating the dialing sequence via coded perforated or magnetic tapes or that directly signal and engage the aforementioned priority-switching circuits that are provided by the telephone company for direct connection with the police, fire, hospital and private patrol agency dispatching services.

The intelligence-imparting device of this invention includes a prerecorded message either on a phonograph disc or on a tape, preferably an endless-belt magnetic tape, and an appropriate reproducer or player for such prerecorded message. The player depending on whether the disseminator unit is internal or external Will reproduce the spoken message by electrical impulses in the case of an internal disseminator and by sound impulses in the case of external units.

Many types of recording and assorted players are available and are easily adapted to function in the alarm system of this invention.

The player mechanism may be designed to send a single message or it may utilize the plurality of channels available on commercial tape-player decks to transmit one of several messages. The choice of channel and the message thereon may be an instance to be determined by the type of emergency or several transmitters in a locality within the radius of a receiver/discriminator may each send their own distinctive signals, the discriminator identifying and activating each channel and the message thereon in response to the distinctive signal. Such a multi-message information disseminating device and associated switching circuits is described in U.S. Patent 2,905,762 where a combined fire and burglar alarm system incorporating distinctive messages for each type of alarm is described.

The alarm system of this invention will now be specifically described in connection with the specific embodiment where the transmitter is a commercial tone-modulated FM transmitter operated in the range 230-300 mc. and incorporating a pulsing circuit for identifying and limiting the transmission sequence. This unit, weighing less than two ounces together with its associated battery can generate a signal that is easily received and identified at a radius of over half a mile.

One such transmitter is manufactured by the Telectron Company of Fort Lauderdale, Florida, for use with automatic gauge door-openers. The receiver/amplifier combination, matched to this type of transmitter, is described in US. Patent 2,931,956. It is designed to detect and discriminate tone-modulated FM signals and to amplify such signals to a level suificient to operate switches controlling electrical equipment. The disseminator unit of this embodiment is essentially the device of US. Patent 2,371,051 modified so that the burglar and fire detection devices are eliminated. The messages is contained on an endless magnetic tape on an appropriate player instead of the phonograph record of the reference.

When the transmitter is activated by pressing and switch 11 mounted on top of the miniaturized activator/transmitter A, it is activated and generates a signal. The receiver/discriminator B detects the signal, amplifies it and the amplified signal activates a solenoid which releases the arm depressing the cradle-switch of the telephone thereby activating the phone circuit. Further, the solenoid releases a dial-engaging finger, permitting the pre positioned spring-tensioned dial to return to its normal position and thereby dialing the operator. The tape player is also started by the amplified signal and the endless tape repeats a prerecorded message such as A holdup is going on at 000 South North Street. Send police at once. The message is constantly repeated to the operator until the lines is disconnected. The device can be reset after help has arrived.

in an experimental trial using the simple equipment described above, the alarm signal was transmitted over a distance of 200 yards from a store where the transmitter was located to a closet in a building where the receiver/disseminator unit and a telephone were located.

The police received the recorded message as switched to them by the telephone companys operator and radio cars were dispatched. The police arrive at the threatened premises within 4 minutes of the original transmission. Road blocks in the area were completed within 5 minutes after the switch was achieved.

A similar transmitter, receiver, and disseminator system was connected to a card dialing telephone and an internal connection was made whereby the telephone circuits were completed and the card number-dialing sequence was initiated in response to the signal from the amplifier. Within thirty-five seconds the dialed number was being rung. When answered by the aide to the doctor whose number was dialed, the message received was Doctor, medical emergency, Mrs. Jane Doe, your patient now at home at 000 North South Street, Apt. 30. Superintendent has key, chronic diabetic, medical emergency. The entire sequence, from pressing the alarm switch on the transmitter to completion of the notation of the message by the doctors aide was accomplished within one minute.

Among the many advantages afforded by the present invention are the ability of the general apparatus to serve many functions. mit alarms, reporting hold-up or armed robbery, the apparatus can, as indicated above, summon assistance for the bed-ridden. Further by connecting the activating switch to a simple watch movements, the apparatus could be adapted to report the failure of night watchmen on their appointed rounds. Failure of the watchman to periodically inactivate the watch would activate the transmitter to send an alarm, either to the police or to a patrol agency informing them that the watchman at the protected premises was in trouble.

Another variation of the apparatus would be its modification for the transmission of fire alarms from untended summer homes. Such summer homes are usually equipped with party-line telephones which, although used only 3 or 4 months a year, are on a standby basis at all In addition the ability to transtimes. Because such telephones are party lines it is difficult for the telephone operator to identify the exact premises at which the emergency is located if there is no positive identification provided. Fire or burglary de- 5 tecting devices connected to the alarm switch of the transmitter can cause the transmission of alarms via the standby party-line telephone with messages to indicate the type of trouble and its location.

It will be noted that although the alarm system of this invention is referred to as consisting of four distinct units, i.e., the transmitter/modulator, the receiver/discriminator, the disseminator and the telephone, the entire system need consist only of two separate devices. They are the self-contained transmitter/modulator with its associated power supply preferably in miniature form, and the rest of the apparatus in a single device with either internal or external telephone connections.

The advantages of the invention lies in the portability of transmitter and the fixed, direct connection to the constantly attended sources of assistance provided by the telephone system and its direct lines to police and other emergency services.

I claim:

An alarm system comprising, in combination:

25 a radio-frequency transmitter concealable :on the person of an operator and energizable to generate a continuous-wave radio-frequency signal for transmission to a location remote from said operator while being provided with switch means concealable on the person of the operator for energizing said transmitter;

a modulator connected with said transmitter for imparting a characteristic modulation to said continuous-wave radio-frequency signal;

radio-frequency receiver disposed at said location and tuned to said radio-frequency signal;

modulation-discriminator means at said location and connected with said receiver for detecting said characteristic modulation of said radio-frequency signal;

activator means at said location energizable by said modulation-discriminator means upon the detection thereby of only said characteristic modulation even in the presence of other radio-frequency signals of similar frequency for open-circuiting a telephone line and dialing thereover a predetermined subscriber number to connect said telephone line with an as sistance-dispatching agency; and

player means at said location actuable by said activator means for transmitting over said telephone line a prerecorded message requesting assistance from said agency.

References Cited by the Examiner UNITED STATES PATENTS OTHER REFERENCES Popular Mechanics, April 1950, pages 133-136 and 248.

DAVID G. REDINBAUGH, Primary Examiner.

Images