VEHICLE BRAKE LIGHT CONTROL SYSTEM

• US 3,846,749 A
• Filed: 02/01/1973
• Issued: 11/05/1974
• Est. Priority Date: 02/01/1973
• Status: Expired due to Term

• Current Assignee: Renwick E. Curry
• Original Assignee: Renwick E. Curry
• Inventors: Curry, Renwick E.
• Primary Examiner(s): Yusko, Donald J.
• Assistant Examiner(s): Leimer, K.
• Application Number:
  US05/328,798
• Time in Patent Office: 642 Days
• Field of Search: 340/62,72
• US Class Current: 340/467
• CPC Class Codes: B60Q 1/444 with indication of the braking strength or speed changes, e.g. by changing shape or intensity of the indication B60Q1/1407, B60Q1/442, B60Q1/447 take precedence

Abstract

A vehicle brake light control system, useful in an automobile, for example, which system causes the brake lights of the vehicle to flash on at a rate dependent on the sum of the deceleration of the vehicle and the derivative of such deceleration when the vehicle is decelerating without the application of the vehicle brakes, to remain on continuously when the brakes are applied and the vehicle deceleration is below a predetermined threshold level, and to flash off at a rate dependent on the sum of the vehicle deceleration and its derivative when the brakes are applied and the vehicle deceleration exceeds such predetermined threshold level.

Claims

1. A vehicle brake light control system comprising means for producing a voltage representative of the deceleration of a vehicle;

means responsive to said deceleration voltage for producing a pulsed signal having pulse repetition rate dependent on the sum of said deceleration voltage and the derivative thereof;

threshold means responsive to said deceleration voltage for producing a threshold signal when said deceleration voltage exceeds a predetermined threshold level;

means for producing a braking signal when the brakes of said vehicle are applied;

brake signal actuation circuit means responsive to said pulsed signal, said threshold signal and said braking signal for flashing on the brake light system of said vehicle at a rate dependent on the repetition rate of said pulsed signal when said vehicle is in a first state wherein it is decelerating without the application of said vehicle brakes, for turning on said brake light system when said vehicle is in a second state wherein said brakes are applied and said vehicle is decelerating at a level below said threshold level, and for flashing off said brake light system at a rate dependent on the repetition rate of said pulsed signal when said vehicle is in a third state wherein said brakes are applied and the vehicle is decelerating at a level which exceeds said threshold level.

2. A vehicle brake light control system in accordance with claim 1 wherein said pulse repetition rate is proportional to said sum;

and said flashing on rate and said flashing off rate are proportional to said pulsed signal repetition rate.

3. A vehicle brake light control system in accordance with claim 1 and further including means for adjusting said predetermined threshold level.

4. A vehicle brake light control system in accordance with claim 1 wherein said deceleration voltage producing means is an accelerometer.

5. A vehicle brake light control system in accordance with claim 1 wherein said deceleration voltage producing means includes means for producing a voltage dependent on the velocity of said vehicle;

and means for differentiating said voltage to produce a voltage proportional to the derivative of said velocity.

6. A vehicle brake light control system in accordance with claim 1 wherein said deceleration voltage producing means includes a hydraulic brake line actuator;

and a pressure transducer responsive to the actuator for producing a voltage representative of the deceleration of said vehicle.

7. A vehicle brake light control system in accordance with claim 1 wherein said pulsed signal producing means includes an operational amplifier responsive to said deceleration voltage for producing an output voltage;

a voltage-controlled oscillator responsive to said output voLtage for producing a trigger signal; and

a pulse forming circuit responsive to said trigger signal for producing said pulsed signal.

8. A vehicle brake light control system in accordance with claim 7 wherein said operational amplifier includes amplifier means;

a first resistance-capacitance circuit connected at the input of said amplifier and responsive to said deceleration voltage;

a second resistance-capacitance circuit connected in a feedback loop between the output and the input of said amplifier, whereby said amplifier produces an output voltage when said vehicle is decelerating, said voltage being dependent on the sum of said deceleration voltage and its derivative.

9. A vehicle brake light control system in accordance with claim 7 wherein said pulse forming circuit is a one-shot multivibrator circuit.

10. A vehicle brake light control system in accordance with claim 1 wherein said brake light actuation means includes logic circuitry for producing a first pulsed signal when said vehicle is in said first decelerating state, a constant signal when said vehicle is in said second decelerating state, and a second pulsed signal when said vehicle is in said third decelerating state, said second pulsed signal being the inverse of said first pulsed signal;

and switching means responding to said logic circuitry for actuating said brake light system in accordance with said first pulsed signal, said constant signal, or said second pulsed signal when said vehicle is decelerating.

11. A vehicle brake light control system in accordance with claim 10 wherein said logic circuitry, includes an array of AND gates responsive to said pulsed signal, said braking signal and said threshold signal so as to produce said first pulsed signal, said constant signal, or said second pulsed signal when said vehicle is decelerating;

and an OR gate responsive to the production of said first pulsed signal, said constant signal, and said second pulsed signal to apply one of said signals to said switching means when said vehicle is decelerating.

12. A vehicle brake light control system in accordance with claim 11 wherein said switching means is a transistor and the output of said OR gate is applied to the base thereof to cause said transistor to actuate the brake light system of the vehicle.