Emergency Radio Warning System

• US 3,864,674 A
• Filed: 12/18/1972
• Issued: 02/04/1975
• Est. Priority Date: 12/18/1972
• Status: Expired due to Term

• Current Assignee: Robert Worsham, Stephen J. Martin
• Original Assignee: Robert Worsham, Stephen J. Martin
• Inventors: Martin, Stephen J., Worsham, Robert
• Primary Examiner(s): Yusko, Donald J.
• Application Number:
  US05/315,856
• Time in Patent Office: 778 Days
• Field of Search: 325/64,18 340/224,171,171PF,171R
• US Class Current: 340/530
• CPC Class Codes: G08B 25/016 Personal emergency signalling and security systems emergency non-personal manually actuated alarm activators G08B25/12

Abstract

A radio warning system includes emergency condition sensors for actuating respective radio transmitters which are modulated by identification generators to produce identification signals which contain one or more frequencies selected from groups of four frequencies in accordance with selected identifying binary coded decimal digits. A transmitted identification signal is detected by a radio receiver in a mobile unit or central dispatch location to operate a memory and a decimal display unit to indicate the existence and location of the emergency condition until reset by an operator. The transmitters are deactuated by a timing circuit after a predetermined period. Delay circuitry prevents operation of the memory and decimal display unit until the identification signal has been received for a predetermined continuous duration.

Claims

1. An emergency radio warning system comprising:

a sensor operable upon an emergency condition;

means operated by the sensor in response to an emergency condition for generating and transmitting a radio signal having a predetermined frequency;

means for modulating the generating and transmitting means with an identification signal having one or more simultaneously generated frequencies selected from a group of four frequencies in accordance with an identifying binary coded decimal digit;

said modulating means including one or more oscillator circuits, each having in circuit a tuning fork filter resonant at a respective selected frequency;

means for receiving the modulAted radio signal and detecting the identification signal;

said receiving and detecting means including four tuning fork filters resonant at the respective four frequencies; and

means responsive to the identification signal for displaying the decimal digit corresponding to the detected identification signal to indicate the location of the emergency condition.

2. A system as defined in claim 1 wherein said receiving and detecting means includes delay means for preventing the operation of the displaying means for a predetermined continuous duration of the presence of an identification signal.

3. An emergency radio warning system comprising:

a sensor operable upon an emergency condition;

means operated by the sensor in response to an emergency condition for generating and transmitting a radio signal having a predetermined frequency;

means for modulating the generating and transmitting means with an identification signal having one or more simultaneously generated frequencies selected from a group of four frequencies in accordance with an identifying binary coded decimal digit;

timing means for terminating the operation of the generating and transmitting means a predetermined duration after initiation of the operation of the generating and transmitting means;

means for receiving the modulated radio signal and detecting the identification signal;

said receiving and detecting means including four filter means for detecting the respective four frequencies, each of said four filter means being non-responsive to signals of less than a predetermined continuous duration;

memory means actuated by the identification signal for producing output signals corresponding to the identifying binary coded decimal digit until reset by an operator; and

means responsive to the output signals of the memory means for displaying the decimal digit corresponding to the identifying binary coded decimal digit to indicate the location of the emergency condition.

4. A system as defined in claim 3 which includes:

an arming circuit interposed between the sensor and the generating and transmitting means, said arming circuit including means for latching in response to the operation of the sensor to operate the generating and transmitting means;

means between the latching means and the transmitting means, operated by the timing means, for terminating the operation of the generating and transmitting means;

means for resetting the latching means; and

means for indicating the latched condition of the arming circuit.

5. A system as defined in claim 3 wherein:

each of the four filter means includes a tuning fork filter and delay means responsive to the output of a respective filter for producing a respective delayed signal after at least a predetermined continuous duration of the presence of an identification signal; and

the memory means includes four binary memory means each responsive to a respective delayed signal for producing an output signal.

6. An emergency radio warning system comprising a sensor operable upon an emergency condition;

means operated by the sensor in response to an emergency condition for generating and transmitting a radio signal having a predetermined frequency;

means for modulating the generating and transmitting means with an identification signal having one or more frequencies selected from a group of four frequencies in accordance with an identifying binary coded decimal digit;

means for receiving the modulated radio signal and detecting the identification signal;

said receiving and detecting means including four filter means for detecting the respective four frequencies, each of said four filter means being non-responsive to signals of less than a predetermined continuous duration;

memory means actuated by the identification signal for producing output signals corresponding to the identifying binary coded decimal digit until reset by an operator;

meAns responsive to the output signals of the memory means for displaying the decimal digit corresponding to the identifying binary coded decimal digit to indicate the location of the emergency condition;

a relay having normally open contacts for applying voltage from a source to the generating and transmitting means when a coil of the relay is energized;

a transistor having an emitter and collector connected in series with the coil and the source;

a resistor;

a first silicon controlled rectifier having its anode and cathode connected in series with the resistor and the source;

means connecting the sensor to a control electrode of the first silicon controlled rectifier for initiating conduction through the first silicon controlled rectifier in response to an emergency condition;

means connected across the resistor for biasing the base of the transistor into conduction in response to the conduction of the first silicon controlled rectifier to operate the generating and transmitting means;

a unijunction transistor timing circuit connected across the resistor;

a second silicon controlled rectifier having its anode and cathode connected between the base of the transistor and a reverse bias potential;

means connecting the unijunction transistor timing circuit to a control electrode of the second silicon controlled rectifier for terminating conduction of the transistor to terminate the operation of the generating and transmitting means; and

means actuated by an operator for momentarily interrupting the source.

7. An emergency radio warning system comprising a sensor operable upon an emergency condition;

means operated by the sensor in response to an emergency condition for generating and transmitting a radio signal having a predetermined frequency;

means for modulating the generating and transmitting means with an identification signal having one or more frequencies selected from a group of four frequencies in accordance with an identifying binary coded decimal digit;

timing means for terminating the operation of the generating and transmitting means a predetermined duration after initiation of the operation of the generating and transmitting means;

means for receiving the modulated radio signal and detecting the identification signal;

said receiving and detecting means including four filter means for detecting the respective four frequencies, each of said four filter means being non-responsive to signals of less than a predetermined continuous duration;

each of the four filter means including a tuning fork filter and delay means responsive to the output of a respective filter for producing a respective delayed signal after at least a predetermined continuous duration of the presence of an identification signal;

memory means actuated by the identification signal for producing output signals corresponding to the identifying binary coded decimal digit until reset by an operator;

said memory means including four binary memory means each responsive to a respective delayed signal for producing an output signal;

means responsive to the output signals of the memory means for displaying the decimal digit corresponding to the identifying binary coded decimal digit to indicate the location of the emergency condition; and

timing means responsive to the operation of a binary memory means for disabling the receiving and detecting means and for enabling the operation of the displaying means after the periods of operation of all the four delay means.

8. A system as defined in claim 7 wherein the timing means for disabling the receiving and detecting means and for enabling the displaying means includes:

a unijunction transistor timing circuit having a predetermined delay which is greater than the difference between the delays of any two of the four delay means;

means for sensing the operation of memory means to operate the unijunction timing circuit;

a relay having a contacT arm for normally engaging a first contact, said contact arm disengaging the first contact and engaging a second contact when a coil of the relay is energized, said contact arm connected to a voltage source, said first contact connected to the receiving and detecting means, said second contact connected to the displaying means;

a silicon controlled rectifier having its anode and cathode in series with the coil; and

means connecting an output of the unijunction transistor timing circuit to a control electrode of the silicon controlled rectifier for energizing the coil after the predetermined delay of the transistor timing circuit to disable the receiving and detecting means and for enabling the displaying means.

9. A sensing and transmitting system for generating a radio signal modulated by identification signals for identifying the location of an emergency condition comprising:

a sensor operable upon an emergency condition;

means operated by the sensor in response to an emergency condition for generating and transmitting a radio signal having a predetermined frequency;

means for modulating the generating and transmitting means with an identification signal having one or more simultaneously generated frequencies selected from a group of four frequencies in accordance with an identifying binary coded decimal digit;

said modulating means including one or more oscillator circuits each having in circuit a tuning fork filter resonant at a respective selected frequency; and

timing means for terminating the operation of the generating and transmitting means a predetermined duration after initiation of the operation of the generating and transmitting means.

10. A system as defined in claim 9 which includes:

an arming circuit interposed between the sensor and the generating and transmitting means, said arming circuit including means for latching in response to the operation of the sensor to operate the generating and transmitting means and to operate the timing means;

manual means for resetting the latching means; and

means for indicating the latched condition of the arming circuit.

11. A sensing and transmitting system for generating a radio signal modulated by identification signals for identifying the location of an emergency condition, comprising:

a sensor operable upon an emergency condition;

means operated by the sensor in response to an emergency condition for generating and transmitting a radio signal having a predetermined frequency;

means for modulating the generating and transmitting means with an identification signal having one or more frequencies selected from a group of four frequencies in accordance with an identifying binary coded decimal digit;

said modulating means including one or more oscillator circuits each having in circuit a tuning fork filter resonant at a respective selected frequency;

a relay having normally open contacts for applying voltage from a source to the generating and transmitting means when a coil of the relay is energized;

a transistor having an emitter and collector connected in series with the coil and the source;

a resistor;

a first silicon controlled rectifier having its anode and cathode connected in series with the resistor and the source;

means connecting the sensor to a control electrode of the first silicon controlled rectifier for initiating conduction through the first silicon controlled rectifier in response to an emergency condition;

means connected across the resistor for biasing the base of the transistor into conduction in response to the conduction of the first silicon controlled rectifier to operate the generating and transmitting means;

a unijunction transistor timing circuit connected across the resistor;

a second silicon controlled rectifier having its anode and cathode connected between the base of the transistor and a reverse bias potential;

means connecting the unijunction transistor timing cirCuit to a control electrode of the second silicon controlled rectifier for terminating conduction of the transistor to terminate the operation of the generating and transmitting means; and

means actuated by an operator for momentarily interrupting the source.

12. A receiving and displaying system which senses and displays an identifying decimal digit from a radio signal which is modulated by an identification signal containing one or more frequencies selected from a group of four frequencies in accordance with a binary coded decimal digit which corresponds to the identifying decimal digit to indicate the location of an emergency condition, comprising means for receiving the modulated radio signal and detecting the identification signal;

four filter means responsive to the respective four frequencies in the identification signal for producing parallel signals corresponding to the binary coded decimal digit;

each of said four filter means being non-responsive to signals of less than a predetermined continuous duration;

means responsive to the signals produced by the four filter means for displaying the identifying decimal digit to indicate the location of the emergency condition;

four memory means actuated by the respective signals from the four filter means for continuing the operation of the displaying means to display the decimal digit after the termination of the radio signal until reset by an operator; and

timing means responsive to the operation of a memory means for disabling the receiving and detecting means and for enabling the operation of the displaying means after the periods of operation of all the four delay means.

13. A system as defined in claim 12 wherein the timing means for disabling the receiving and detecting means and for enabling the displaying means includes:

a unijunction transistor timing circuit having a predetermined delay which is greater than the difference between the delays of any two of the four delay means;

means responsive to the actuating of any of the four memory means for operating the unijunction timing circuit;

a relay having a contact arm for normally engaging a first contact, said contact arm disengaging the first contact and engaging a second contact when a coil of the relay is energized, said contact arm connected to a voltage source, said first contact connected to the receiving and detecting means, said second contact connected to the displaying means;

a silicon controlled rectifier having its anode and cathode in series with the coil; and

means connecting an output of the unijunction transistor timing circuit to a control electrode of the silicon controlled rectifier for energizing the coil after the predetermined delay of the transistor timing circuit to disable the receiving and detecting means and to enable the displaying means.

14. A system as defined in claim 12 which includes:

four memory means actuated by the respective signals from the four filter means for continuing the operation of the displaying means to display the decimal digit after the termination of the radio signal until reset by an operator.

15. A system as defined in claim 12 wherein each of the four filter means includes:

a tuning fork filter, and a delay means between the respective filter and the displaying means for preventing the operation of the displaying means for a predetermined continuous duration of the presence of an identification signal.

16. A system as defined in claim 12 wherein each of the four filter means includes a tuning fork filter.