US3723876A - Emergency distress signaling system - Google Patents

Abstract

A system for addition to a conventional dispatched vehicle twoway radio communication system to enable an operator to notify a central dispatcher of an emergency condition arising after the operator leaves the vehicle. The system includes a unit which plugs directly into the microphone input of the conventional system and which is responsive to a signal transmitted from a portable transmitter carried by the operator for playing a prerecorded emergency message through the transmitter of the conventional radio system.

Description

United States Patent 1191 Seaborn, Jr.

[ Mar. 27, 1973 [54] EMERGENCY DISTRESS SIGNALING SYSTEM [76] Inventor: George C. Seaborn, Jr., 926 Warfield, Richardson, Tex.

[22 Filed: June 21,1971

[21] Appl. No.: 155,098

Primary Examiner-Robert L. Griffin Assistant Examiner-Barry L. Leibowitz AttorneyRichards, Harris & Hubbard [57] ABSTRACT A system for addition to a conventional dispatched vehicle two-way radio communication system to enable an operator to notify a central dispatcher of an emergency condition arising after the operator leaves 100 l C the vehicle. The system includes a unit which plugs directly into the microphone input of the conventional [56] I Reerences Cited system and which 18 responsive to a signal transmitted from a portable transmitter carried by the operator for UNITED STATES PATENTS playing a pre-recorded emergency message through the transmitter of the conventional radio system. 3,290,597 12/1966 Denny ..325/64 3,316,488 4/1967 Reynolds ..325/139X 7 Claims, 9 Drawing Figures g V? l [f 27535??? TRANSMITTER RECEIVER [DECODER-H DETECTOR/OWNER H i SQL 7% RESET CYCLING MESSAGE SWITCHING TIMERTIMER CIRCUIT TAPE 55 56 575a 29SOURCE 6 AUDIO PTT MIKE Patented March 27, 1973 1 3,723,876

5 Sheets-Sheet 1 INVENTORI GEORGE C. SEABORN, JR

ATTORNEYS EMERGENCY DISTRESS SIGNALING SYSTEM BACKGROUND OF THEINVENTION 1. Field of the Invention The invention relates to a dispatched vehicle radio communications system, and more particularly to an emergency assistance notification system for a conventional communication installation.

2. History of the Prior Art Two-way dispatched vehicle communication systems have been employed in many different fields. The foremost of these applications have been for police and other public safety and law enforcementorganizations although many others such as firemen, private security patrols, etc., use such communication systems extensively. In a two-way police radio system, the generally accepted practice is for a central dispatcher to notify an available patrol car unit of the existence of a need for assistance at a certain location. The patrol car proceeds to that location and then notifies the dispatcher of his arrival there. Once a police officer leaves the vehicle to investigate the need for assistance, his contact with the outside world, and in particular the dispatcher, no longer exists for all practical purposes. That is, if the officer encounters difficulty with handling the situation, for example, if he becomes involved with an armed belligerent, there is no way for him to notify anyone or seek help without returning to the patrol car. If the belligerent has obtained control of the situation and has subdued the police officer, there is absolutely nothing than can be done to summon further aid to the officers rescue. The present system seeks to lessen the danger of a single police officer investigating an incident and to more fully utilize the existing twoway communication system in a police car to notify the dispatcher of his need for aid. Previous systems which have sought to expand the effectiveness of an existing dispatched vehicle communication system, such as that shown in U. S. Pat. No. 3,290,597 to G. R. Denny et al., have required extensive modification of the mobile radio equipment. In the Denny et al patent, a police officer carries a portable transmitter unit which sends a distress signal to a special receiver integrated directly into a mobile vehicle radio. Reception of the distress signal activates the con ventional mobile transmitter and notifies the dispatcher of the need for aid. Systems of this type require extensive modification of the radio equipment which is carefully regulated by both federal and state agencies, such as the Federal Communications Commission. Extensive testing must be done before such equipment is approved for use. The present add-on system provides a simple plug-in addition to existing equipment, and requires no prior FCC approval before use. Further, the add-on equipment of the present invention can be used with conventional mobile systems and implements emergency signals without requiring replacement of existing radio.

BRIEF SUMMARY OF THE INVENTION An add-on emergency assistance radio signaling system for use with a conventional dispatched vehicle communication system which includes a vehicle mounted radio receiver and transmitter having a control head including a detachably connected microphone for communication with the central dispatcher. The emergency system comprises a connector having a first input terminal adapted for connection to the microphone of the conventional system. The

connector also has a second input terminal and an output terminal which is connected to the control head microphone input connection of the vehicle mounted transmitter. The connector couples both the first and second input terminals to the output terminal to permit normal usage of the microphone with the vehicle mounted transmitter. The system includes a normally unactuated pre-recorded emergency' assistance message player having an output connected to the second input terminal for coupling a message signal into the control head microphone input connection of the vehicle mounted transmitter to transmit the recorded message to the dispatcher. A portable radio transmitter is adapted for carriage by an operator and has a manually operated switch for actuating the transmitter in the event of the operators need for emergency assistance. A radio receiver detects the signals transmitted by the portable transmitter to operate means for actuating the pre-recorded emergency assistance message player to notify the dispatcher of the operator's need for emergency assistance.

BRIEF DESCRIPTION OF- THE DRAWINGS For a more complete understanding of the present invention and for further objects and advantages thereof, reference may now be had to the following description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a front view of the dashboard of an emergency vehicle showing the control head of a two-way radio incorporating the system of the present invention;

FIG. 2 is a perspective view of a portable embodiment of the present invention, having the cover of the case opened to show the contents;

FIG. 3 is a perspective view of a portable transmitter carried by an operator;

FIG. 4 is a block diagram of the system of the present invention;

FIG. 5 is a schematic diagram of the control equipment of the present invention;

FIG. 6 is a schematic diagram of the portable transmitter of FIG. 4; and

FIGS. 7-9 are schematic diagrams of alternate embodiments of triggering arrangements for the transmitter of FIG. 6.

DETAILED DESCRIPTION FIG. 1 shows a front view of the dashboard of a police patrol car or other emergency vehicle showing an under-dash mounted control head 10 for a conventional two-way radio system. The control head 10 includes an on-off switch 11 and volume and squelch control knobs I2 and 13, respectively. A pair of lamps 12a and 13a indicate, respectively, operation of the system receiver and transmitter. A conventional system includes amicrophone 14 having a push-to-talk switch 15 and acord 16. Thecord 16 is terminated by amulticontact microphone plug 17 which ordinarily is fitted into a control headmicrophone input connector 18. In certain radio systems, the microphone cord may be permanently attached to the control head. In such cases, a microphone input connector can be easily added to the control head.

The present system of the invention, as shown in its portable embodiment, includes acarrying case 19 which will be further discussed in connection with FIG. 2 below. Thecarrying case 19 has extending therefrom aflexible cord 21 terminated by amulti-contact plug connector 22 which is fitted into the control headmicrophone input connector 18 instead of themicrophone plug 17. The mike plug is, instead, connected to aninput connector 23 on the outside of thecarrying case 19. The system of the invention is now completely added-on to the existing conventional communication equipment and only requires activation of the controls on the outside of thecarrying case 19 for operation.

FIG. 2 shows a top perspective view of thecarrying case 19 with the cover open to show the equipment therein. Mounted within thelid 24 of thecarrying case 19 is a foldedantenna 25 for receiving signals from a portable transmitter unit and coupling those signals into areceiver 26 contained within thecarrying case 19. The signaling system of the invention could also be used with a removable antenna mounted upon the outside of the vehicle and plugged into thecarrying case 19. Thecase 19 also mounts apre-recorded message player 29, such as a cassette tape player, having an opening on itsfront surface 31 for receiving aprerecorded message cassette 32 which can be changed to vary the message. Also housed within thecarrying case 19 is acontrol circuit 28 which controls activation and timing of themessage player 29 and a portable operator-carriedtransmitter unit 33 stored within thecase 19 and which will be described more fully below in connection with FIG. 3.

The controls for the system of the invention are mounted on the outside of thecarrying case 19 and include an on-off-test switch 34, theinput connection 23 for the microphone of the system, atest switch 36, an on-off indicator lamp 37 and atest lamp 38. Thecarrying case 19 is also shown equipped with aclip 39 mounted to the outside surface for mounting theportable transmitter unit 33. I

Power for the system of the invention can be derived from either a battery mounted within thecase 19 or from the battery of the vehicle. In the latter case, a power cord and plug 30 extend from thecase 19 and may be inserted into the vehicle cigarette lighter socket or to a special connector leading directly to the vehicle battery.

FIG. 3 shows a perspective view of theportable transmitter unit 33. The transmitter includes conventional crystal controlled A.M. transmitter circuitry with an output power on the order of 100 milliwatts. The output of thetransmitter 33 is connected to a tape-type transmitting antenna 44 which can be easily threaded through the loops of an operators belt or disposed in any manner to extend the antenna to a substantial length. Thetransmitter 33 may be fixed to the loop of the operators belt with aclip 42 similar to the type used to clip a measuring tape to a workmans belt. Thetransmitter unit 33 includes an emergencyassistance actuation button 45 which is mounted within a recessedportion 46 on the surface of the housing to prevent accidental triggering of an emergency signal. Thetransmitter 33 has an on-off-test switch 40 for energizing the unit. The test position transmits a signal to thereceiver 26, of FIG. 2, and activates themessage player 29 and bile transmitter of the vehicle radio system. The carrier signal from the transmitter is amplitude modulated by a I high stability two-tone oscillator which produces an audio or sub-audio coded output signal.

A block diagram of the system of the present invention is shown in FIG. 4. The portion of the system enclosed within the carryingcase 19 of FIG. 1 includes thereceiver 26 and the foldedantenna 25. The signal transmitted by theantenna 44 ofportable transmitter 33 is two-tone modulated by anencoder 52. The signal from thereceiver 26 passes through adecoder 51 which operates in response to the same two tones as theencoder 52 produces to prevent inadvertent actuation by a spurious signal. The output of thedecoder 51 is fed to a detector/driver 53 which is connected to a latchingcircuit 54. Areset switch 55 is provided for resetting the system after use. The latchingcircuit 54 controls acycling timer 56 which operates amessage timer 57 to control a switchingcircuit 58. The switchingcircuit 58 performs two functions; first, it energizes thepre-recorded message player 29 and secondly, at the same time applies a signal to the pushto-talk lead of themicrophone input connection 18 to activate the mobile radio transmitter. This simultaneous actuation by the switchingcircuit 58 delivers the pre-recorded emergency message signal into the existing vehicle transmitter.

FIG. 5 is a schematic diagram of the timing and control circuitry of the present invention, and includes thedetector driver circuit 53, the latching circuit and reset 54 and 55, thecycling timer 56, themessage timer 57 and the switchingcircuit 58, all of FIG. 4. When a signal from the receiver and decoder is impressed upon input terminal 61, the signal is rectified and filtered by adiode detector 62 and capacitor 62A which applies a signal to the base of atransistor 63. Operation of thetransistor 63 supplies current to a latchingSCR 64. TheSCR 64 latches conductive until it is reset through a normally closedreset switch 55. Conduction of theSCR contact 64 applies current from asource 65 through the on-off switch 34 to aresistor 69 and acapacitor 71 forming an RC timing network in thecycle timer 56. When a sufficient value of voltage is reached on thecapacitor 71, atransistor 72 begins to conduct, which in turn energizes the base lead of atransistor 73. Current from thetransistor 73 begins to charge amessage timing capacitor 74 the voltage across which is applied to the base of atransistor 75. When the voltage on thetransistor 75 has reached a prescribed value, current is delivered to the base of atransistor 76 which in turn effects conduction of atransistor 77 to energize the coil of a switchingrelay 78. Operation of therelay 78 delivers current to the power input of a tape player throughcontacts 81 and ground to the push-to-talk lead of the control head microphone input connector through contacts 82. Ground is also applied throughcontacts 84 and acapacitor 85 to the base of thetransistor 72 to effect values in the RC network. Passage through one cycle by thetimer 56 energizes themessage timer 57, the period of which is controlled by thecapacitor 74 and resistor 74A and should be the time required to deliver a complete message from the tape, for example 8 seconds. At the end of the tape message, the switchingrelay 78 is released and not reactuated again untilthe cycling timer has passed through its 45 second period to reoperate themessage timer 57. It should be noted that once the latchingSCR 64 has been triggered, the system continues to cycle and periodically deliver messages until someone returns to the equipment and depresses the reset switch 67. Nothing which is done to theportable transmitter unit 33 can affect the periodic delivery of the recorded emergency message to the dispatcher.

FIG. 6 is a schematic diagram of the encoder and transmitter circuitry used in conjunction with the present invention, and includes anencoder 102 and a transmitter stage comprising acrystal oscillator 103 and a final amplifier 104. When the portabletransmitter power switch 40 is in the on" position, closing of theactuation switch 45 applies power to energize theencoder 102, thecrystal oscillator 103 and the final amplifier 104 to produce a radio frequency carrier signal as an output from thecrystal oscillator 103. The frequency of the RF signal is controlled by aquartz crystal 105.Resistors 106, 107 and 108 supply a bias voltage to atransistor 109 which provides amplification. A pair ofcapacitors 110 and 111 provide capacitive reactance to sustain the RF oscillations. A tuned LC circuit comprising avariable capacitor 112 and in.-ductor 113 is tuned to the transmitting RF signal.Inductors 113 and 114 serve as an air-wound transformer to provide a drive signal to afinal amplifier transistor 115. Thetransistor 115 is biased by aresistor 116. A pair ofcapacitors 117 and 118, together with an inductor 119, provide an impedance match between theamplifier transistor 115 and an output tank circuit comprising avariable capacitor 120 and aninductor 121.

Theinductors 121 and 122 act as an air-wound transformer to couple RF power from the output stage of the transmitter to anantenna 44.

Theencoder stage 102 comprises atransistor 123 which is biased by a pair ofresistors 124 and 125. Oscillation is sustained due to capacitive reactance from acapacitor 126. A pair of audio or sub-audio modulating frequencies are generated by two tunedtransformers 127 and 128. Individual modulating frequencies are determined by an LC tuned circuit, one on each of thetransformers 127 and 128. Transformer winding 129 andcapacitor 130 provide a tuned circuit for thetransformer 127 while transformer winding 121 andcapacitor 132 provide a tuned circuit for thetransformer 128. Both-transformers 127 and 128 are driven by atransistor 123 through aresistor 124 andwindings 133 and 134. Oscillation is sustained due to feedback through thetransformer windings 135 and 136 and acapacitor 126. Modulation is coupled from the twotransformers 127 and 128 to the transmitter throughwindings 137 and 138. The signal delivered to the input of the transmitter stage comprises two audio or subaudio tones and is employed to amplitude modulate the RF signal from the transmitter.

The complete system functions as follows after the system has been set up as shown in FIG. 1. Before an operator leaves the vehicle, he may desire to test the system by depressing the test switches 34 and 40 on the carryingcase 19 andtransmitter 33 to insure proper operation of the system. When the operator leaves the vehicle, he carries along with him theportable transmitter 33. If while the operator is investigating a situation at a distance from the car he encounters difficulty and needs assistance, he depresses theactuation button 45 on the side of thetransmitter unit 33 to transmit a two-tone coded, amplitude modulated carrier signal which is received by theantenna 25. Theantenna 25 is connected to thereceiver 26 which upon receiving the signal passes it through thedecoder 51. Two tuned circuits in the decoder discriminate the incoming signal, passing only the two coded signals, if present, through two logic AND gates to energize the detector/driver 53. Receipt of a signal from the transmitter then energizes the latchingcircuit 54 which starts thecycle timer 56 and themessage timer 57 to periodically deliver an emergency assistance message through the control head microphone input connection. The message is transmitted through the conventional radio system of the vehicle to notify the dispatcher of the existence of the need for aid. Because the operator had previously reported his position to the dispatcher when he arrived, there is generally no question of where the aid is needed. The system can be adapted to provide for emergency location of a vehicle which is transmitting a message.

Under certain circumstances, it may be difficult or impossible for an operator carrying theportable transmitter unit 33 to operate the distress signal without calling attention to the fact. Several embodiments of both automatic and secret actuation means have been included to provide means by which the portable transmitter may be actuated covertly.

FIG. 7 is a schematic diagram of a tilt operating mercury switch actuator which may be included within theportable transmitter 33. Asshown, a normallyunactuated mercury switch 201 is connected to the input of an energizing circuit. When the transmitter is in an upright position, mercury within theswitch 201 is near one end of the switch and there is an open circuit between the two internal contacts. When the transmitter is placed in a horizontal position, due perhaps to the person carrying the transmitter having assumed a horizontal position, themercury switch 201 closes to energize a time delay circuit through the input terminals A andB. A resistor 202 and acapacitor 203 provide an RC time constant so that when the voltage across thecapacitor 203 is great enough to overcome the base-emitter voltage of atransistor 204 and the break-down voltage of aZener diode 205, then base current flows into thetransistor 204. Base current places thetransistor 204 into a conductive state and current flows through aresistor 206 and theZener diode 205 to operate atransistor 207. When conducting,transistor 207 completes a circuit path between the input terminal A and the output terminal C which actuates the portable transmitter unit. Aresistor 208 serves to reduce leakage current through thetransistor 207 while themercury switch 201 is open in order to prolong portable battery life. Aresistor 209 provides a discharge path forcapacitor 203 when theswitch 201 is open. The time delay circuit comprising theRC network 202 and 203 prevents accidental actuation due to a temporary closure of the mercury switch which is not intended to operate the transmitter.

P16. 8 shows a magnetically actuated switch including areed switch 212 leading to a pair of output terminals. Placing amagnet 211, which may be mounted in the head of a ballpoint pen, near theswitch 212 causes amagnetic reed 213 to move toward the magnet thereby closing theterminals 214 and 215. This closure of theswitch 212 creates a closed circuit between-the output terminals D and E and actuates the transmitter.

FIG. 9 is a schematic drawing of a pressure actuated switch. Such a switch may be used to operate the transmitter in response to movement of a particular part of an operators body or an object, for example, removal or a revolver from its holster. The switch includes a pair of output terminals D and E. A positive pressure exerted upon themechanical switch 223 causes the terminals to close and complete the circuit between the output terminals. Completion of the circuit actuates the transmitter to transmit an alarm signal. The embodiment of the FIG. 9 switch is basically a remote push button for the portable transmitter.

It is to be understood that the embodiment shown of the invention above is of the portable variety and the system could be easily adapted to a permanent installation within a vehicle by mounting the equipment within thecase 19 at a convenient location under the dash of the vehicle.

Having described the invention in connection with certain specific embodiments thereof, it is to be understood that further modifications may now suggest themselves to those skilled in the art and it is intended to cover such modifications as fall within the scope of the appended claims.

What is claimed is:

1. A portable add-on emergency assistance radio signaling system for interconnection into a conventional dispatched vehicle communication system already present in a vehicle, said conventional dispatched vehicle communication system including a vehicle-mounted radio receiver and transmitter having a control head including a detachably connected microphone for communication with a central dispatcher, wherein said portable add-on emergency assistance radio signaling system comprises:

a portable add-on unit for being removably'electrically plugged in between said microphone and said control head to enable normal conventional usage of said microphone with said vehicle-mounted transmitter;

said add-on unit further including a normally unactuated pre-recorded emergency assistance message player having an output connected to the input of said control head; U

a portable radio transmitter adapted for carriage by an operator and having a switch operable to actuate said portable radio transmitter in the event of the operators need for emergency assistance, said portable radio transmitter generating a signal which is modulated by coded frequency tones; radio receiver mounted within said add-on unit receptive to signals transmitted by said portable transmitter and including means for decoding said coded frequenc tones; and I means within sat add-on unit IBSPOllSlVfilO reception of a signal from said portable transmitter by said receiver mounted in said portable add-on unit for both actuating said pre-recorded emergency assistance message player and for coupling a message signal into said control head to notify the dispatcher of the operator's need for emergency assistance.

2. An add-on emergency assistance radio signaling system as set forth inclaim 1 wherein said message player actuating means includes:

a timing circuit actuated in response to reception ofa transmitted signal by said receiver for energizing said player for a preselected period of time and then deactuating said player.

3. An add-on emergency assistance radio signaling system as set forth inclaim 1, wherein said message player actuating means includes:

a cycle timing circuit actuated in response to reception of a transmitted signal by said receiver, said circuit cyclically remaining actuated for a first preselected period of time and then deactuated for a second preselected period of time; and

a message timing circuit triggered in response to actuation of said cycle timing circuit and remaining actuated for a third preselected period of time of energizing said message player during the third preselected period and then cyclically repeating each time said cycle time is actuated.

4. An emergency assistance radio signaling system as set forth inclaim 1 wherein said message player actuating means includes a relay having a normally open contact set, one of said contacts being connected to a power source and the other being connected to the power input of said player, said relay being operated in response to reception of a signal from said portable transmitter by said receiver.

5. An emergency assistance radio signaling system as set forth inclaim 1 wherein said portable radio transmitter comprises:

a radio frequency transmitter including a crystal controlled oscillator for generating a carrier signal for said transmitter; an encoder for producing a plurality of preselected tones for amplitude modulating the carrier from said transmitter; and wherein said signal responsive means includes a decoder and gating means responsive to a transmitter carrier signal modulated by said plurality of preselected tones.

6. An emergency assistance radio signaling system as set forth inclaim 1 wherein said portable transmitter also includes:

means for actuating said transmitter upon disorientation of the transmitter body from a predetermined position for a preselected period of time.

' 7. An emergency assistance radio signaling system as set forth inclaim 1 wherein said portable transmitter also includes:

an actuation switch formed of magnetic material;

and

a movable magnet, said actuation switch being closed in response to proximity of said magnet to said switch. a

Claims (7)

1. A portable add-on emergency assistance radio signaling system for interconnection into a conventional dispatched vehicle communication system already present in a vehicle, said conventional dispatched vehicle communication system including a vehicle-mounted radio receiver and transmitter having a control head including a detachably connected microphone for communication with a central dispatcher, wherein said portable add-on emergency assistance radio signaling system comprises: a portable add-on unit for being removably electrically plugged in between said microphone and said control head to enable normal conventional usage of said microphone with said vehiclemounted transmitter; said add-on unit further including a normally unactuated prerecorded emergency assistance message player having an output connected to the input of said control head; a portable radiO transmitter adapted for carriage by an operator and having a switch operable to actuate said portable radio transmitter in the event of the operator''s need for emergency assistance, said portable radio transmitter generating a signal which is modulated by coded frequency tones; a radio receiver mounted within said add-on unit receptive to signals transmitted by said portable transmitter and including means for decoding said coded frequency tones; and means within said add-on unit responsive to reception of a signal from said portable transmitter by said receiver mounted in said portable add-on unit for both actuating said prerecorded emergency assistance message player and for coupling a message signal into said control head to notify the dispatcher of the operator''s need for emergency assistance.

2. An add-on emergency assistance radio signaling system as set forth in claim 1 wherein said message player actuating means includes: a timing circuit actuated in response to reception of a transmitted signal by said receiver for energizing said player for a preselected period of time and then deactuating said player.

3. An add-on emergency assistance radio signaling system as set forth in claim 1, wherein said message player actuating means includes: a cycle timing circuit actuated in response to reception of a transmitted signal by said receiver, said circuit cyclically remaining actuated for a first preselected period of time and then deactuated for a second preselected period of time; and a message timing circuit triggered in response to actuation of said cycle timing circuit and remaining actuated for a third preselected period of time of energizing said message player during the third preselected period and then cyclically repeating each time said cycle time is actuated.

4. An emergency assistance radio signaling system as set forth in claim 1 wherein said message player actuating means includes a relay having a normally open contact set, one of said contacts being connected to a power source and the other being connected to the power input of said player, said relay being operated in response to reception of a signal from said portable transmitter by said receiver.

5. An emergency assistance radio signaling system as set forth in claim 1 wherein said portable radio transmitter comprises: a radio frequency transmitter including a crystal controlled oscillator for generating a carrier signal for said transmitter; an encoder for producing a plurality of preselected tones for amplitude modulating the carrier from said transmitter; and wherein said signal responsive means includes a decoder and gating means responsive to a transmitter carrier signal modulated by said plurality of preselected tones.

6. An emergency assistance radio signaling system as set forth in claim 1 wherein said portable transmitter also includes: means for actuating said transmitter upon disorientation of the transmitter body from a predetermined position for a preselected period of time.

7. An emergency assistance radio signaling system as set forth in claim 1 wherein said portable transmitter also includes: an actuation switch formed of magnetic material; and a movable magnet, said actuation switch being closed in response to proximity of said magnet to said switch.

Images