Vehicle danger indicating system

• US 3,921,127 A
• Filed: 12/05/1974
• Issued: 11/18/1975
• Est. Priority Date: 12/07/1973
• Status: Expired due to Term

• Current Assignee: Henri Billottet, Jean-Raymond Narbaits-Jaureguy
• Original Assignee: Henri Billottet, Jean-Raymond Narbaits-Jaureguy
• Inventors: Narbaits-Jaureguy, Jean-Raymond, Billottet, Henri
• Primary Examiner(s): Habecker, Thomas B.
• Application Number:
  US05/529,942
• Time in Patent Office: 348 Days
• Field of Search: 340/32
• US Class Current: 340/901
• CPC Class Codes: G08G 1/164 Centralised systems, e.g. external to vehicles

Abstract

A system for indicating danger to a vehicle comprises a fixed part on the ground in the form of sensors which are arranged along a traffic lane and which are capable of detecting a vehicle situated in their zones of sensitivity. Such a signal, termed a presence signal, is transmitted to a centralised master control circuit via all the preceding sensors and in each sensor through which it passes it triggers a signal which gives the distance between the vehicule and the sensor. This signal is received by another vehicle situated in the zone of sensitivity of the transmitting sensor. When compared with a signal which indicates a socalled safe distance, the first signal triggers a danger indicator when this is necessary.

Claims

1. A system for indicating danger to a vehicle, travelling along a traffic lane, particulary when the distance between said concerned vehicle and another in front thereof is substantially lessening, comprising fixed means associated with said traffic lane for detecting the presence of vehicles on said lane, said fixed means having means for transmitting said presence information, means aboard vehicles for receiving said presence information and deriving therefrom whether said presence information comes from a vehicle in front of said concerned vehicle and means for generating a safety signal when said presence information as a pulse is within a signal of predetermined length corresponding to a predetermined safety distance from said concerned vehicle.

2. A system as claimed in claim 1 comprising fixed means having a plurality of sensors associated with said traffic lane, said sensors being distributed along said lane, a master control device emitting synchronising pulses for triggering said sensors sequentially and said triggering resulting in a sensitivity zone around said sensors in which a vehicle can be detected, transmitting means in said sensors for transmitting a presence signal relating to a vehicle in such sensitivity zone to the said master control device via all the preceding sensors in turn, and said presence signal triggering said sensors as it passes therethrough, receiving means aboard vehicles adapted to receive said signals transmitted by said sensors, said means comprising means for discriminiating between said received signals derived from said synchronising pulses and said received signals derived from said presence signals, a safety pulse generator means for generating said danger signal when said presence signal from a vehicle in front of that concerned is within a predetermined distance from said concerned vehicle and means for displaying said danger signal.

3. A system as clAimed in claim 2, wherein said receiving means aboard said vehicle comprises means for sensing the speed of said vehicle, means for sensing external conditions relating to said lane, both said means feeding to said safety pulse generator delivering said danger signal as a function of the speed of said vehicle and said external conditions.

4. A system as claimed in claim 1 wherein said receiving means aboard said vehicle includes a watch device having an indicator which is fed directly by said synchronising pulses.

5. A system as claimed in claim 4 wherein said watch device includes further a warning indicator which is fed via a complemented AND circuit by said synchronising pulses and by pulses proportional to the speed of said vehicle which are supplied by said speed sensing means, said warning indicator indicating that said vehicle is travelling at a speed considered to be too low, being possibly zero.

6. A system as claimed in claim 1 wherein said receiving means comprises at least one circuit for discriminating between said synchronising pulses and said presence pulses on the basis of one of their differing characteristics, length and frequency as the case may be.

7. A system as claimed in claim 2 comprising a plurality of sensors, said saisors having each a transmitter, a receiver, and a transit channel for transmitting said presence signal from another sensor situated behind and regenerating it as it passes therethrough, sais signal triggering said transmitter of said sensor and means for determining the delay between said signal and the synchronising pulse applied to the said sensor for deriving the distance separating said vehicle from said sensor.

8. A system as claimed in claim 5 wherein a vehicle situated in the zone of sensitivity of a sensor receives the signals indicating the presence of another vehicle which has been detected by another sensor and transmits and re-emits them.

9. A system as claimed in claim 2 wherein said discriminating means comprises a circuit for separating said synchronising pulses and a circuit connected to said latter for separating said presence signals said circuits including a double differentiation circuit receiving a signal from a sensor, a first monostable which is triggered by the positive-going peaks delivered by said double differentiation circuit, a first input of a AND circuit connected to say first monostable, a second input of said AND circuit receiving the negative-going peaks from said double differentiation circuit, a second double differentiation circuit which is connected to the output of said first monostable circuit, a diode and a second monostable so connected that said second monostable circuit is triggered by the negative-going peaks from said second double differentiation circuit and second AND circuit which is connected to the output of the said second monostable circuit and receives at its other input said negative-going peaks from said first double differentiating circuit said first AND circuit supplying a pulse corresponding to a synchronising pulse and said second AND circuit supplying a pulse corresponding to a presence pulse.

10. A system as claimed in claim 3 wherein said safety pulse generator comprises, a first monostable circuit (70) which is triggered by said synchronising pulses a first integrator circuit (3900) having means for selecting said external data and supplying a sawtooth signal the slope of which is proportional to said external data, a second integrator circuit fed with said speed pulses (313) and supplying a DC voltage proportional to said speed of said vehicle, an intersection circuit connected to said previous circuits and which supplies short, negative-going pulses, a second monostable circuit which is triggered by said synchronising pulses and is blocked by said negative-going pulses and which delivers at its output rectangular pulse signals the length of which is proportional both to said speed of said vehicle and to said selected external conditions.

11. A system as claimed in claim 10 wherein said first integrator circuit (3900) comprises a plurality of capacitors (702, 703, 704) in parallel, the terminals of which are capable of being selected by a moving contact 705 in accordance with said external conditions which need to be taken into consideration.

12. A system as claimed in claim 10 wherein said safety pulse generator includes further a device for resetting to zero at each synchronising pulse.

13. A system as claimed in claim 4 wherein the time of operation of said monostable circuits is less than the repetition period of said synchronising pulses.

14. A system as claimed in claim 5 wherein said watch device comprises, a first monostable circuit which is triggered by said speed pulses, a gate circuit which is connected to said monostable circuit and which, when open, allows through said synchronising pulses a second monostable circuit (92) which is triggered by said synchronising pulses, an integrator circuit which supplies a sawtooth signal an intersection circuit which has an adjustable threshold to set a minimum speed for said vehicle, the intersection between said threshold and said sawtooth signal producing a train of negative going pulses a third monostable circuit triggered by said train of negative pulses and having an output feeding a warning indicator.

15. A system as claimed in claim 14 comprising further a fourth monostable circuit which is triggered by said synchronising pulses and supplies a pilot light directly.

16. A danger indicating system for vehicles substantially as described with reference to the appended figures.