Abstract:
An emergency-stop warning unit and a method for the control thereof, serve for reducing the severity and chance of rear-end collisions. The invention utilizes a deceleration or collision impact sensor and vehicle electric power-source to turn on the white Reverse-Light upon high deceleration of the vehicle, providing the follow-on vehicle with an early warning of an emergency stop or actual collision impact. The Reverse-Light, in an unexpected circumstance, provides a self-explanatory, sharp, clear and timely warning to the following driver to initiate a defensive action.

Description:
RELATED APPLICATIONS 
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     FEDERAL SPONSORED 
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     MICOFICHE APPENDIX 
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     BACKGROUND OF THE INVENTION 
     In many rear-end collisions between vehicles, an extra distance of a fraction of a yard could have prevented the collision impact and the injury. This extra distance is lost at the beginning of the emergency stop, when the following driver fails to recognize the severity of the deceleration of the vehicle ahead. The following driver is wasting a precious second before initiating the full emergency braking capability of the vehicle. An early, clear, specific, and instinctively understood warning signal, based on the actual deceleration of the vehicle utilizing the Brake-Lights in combination with the Reverse-Lights, provides such a warning. 
     BRIEF SUMMARY OF THE INVENTION 
     An emergency-stop warning unit and a method for the control thereof, serve for reducing the severity and chance of rear-end collisions. The invention utilizes a deceleration or collision impact sensor, and a vehicle electric power-source, to turn on the white Reverse-Light upon high deceleration of the vehicle, for a period sufficient to put the following driver on notice of an emergency condition. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG.  1 . General view of a vehicle and the location of the major elements. 
     FIG.  2 . Deceleration Sensor connection to the Brake-Lights line and Reverse-Lights line. 
     FIG.  3 . Deceleration Sensor, using a conductive liquid in an elongated sealed hollowed tube with two conductive contacts. 
     FIG.  4 . Deceleration Sensor, using a pendulum with a conductive surface and two conductive brushes. 
     FIG.  5 . Deceleration Sensor, using a mass and a spring with a conductive surface on the mass and two conductive brushes. 
     FIG.  6 . Deceleration Latching circuit, to hold the warning signal after termination of the deceleration until power is removed from the Brake-Lights. 
     FIG. 7. 1 G Deceleration sensor One-Shot circuit, to hold the warning signal after collision impact for a given selectable time, using a single switching relay and 2 diodes. 
     FIG. 8. 1 G Deceleration sensor One-Shot circuit, to hold the warning signal after collision impact for a given selectable time, using dual switching relay. 
    
    
     DETAILED DESCRIPTION 
     An emergency-stop warning unit, and a method for the control thereof, serve for reducing the severity and chance of rear-end collisions. The invention utilizes a deceleration or collision impact sensor and a vehicle electric power-source, to turn on the white Reverse-Light upon high deceleration of the vehicle, for a period sufficient to put the following driver on a notice of an emergency condition. 
     An electric line is connected to the Brake-Light line to provide electric power when a lead vehicle uses the brakes. When the lead vehicle is subjected to a high deceleration above 0.2 G ( 0.2 of Gravity, approximately 2 meters per second square) as result of an emergency-stop or a collision impact with another object, a deceleration sensor shorts the Brake-Lights power to the Reverse-Lights line. The combination of the Brake-Lights and the Reverse-Lights indicates to a following driver that the vehicle ahead is in a process of an extreme deceleration that requires a defensive action such as changing lane, or stopping his or her vehicle as rapidly as possible. 
     The deceleration sensor may be made of a sealed hollowed tube with a conductive liquid inside. The tube is positioned in an angle pointing in the direction of the front end of a vehicle and in an 11 to 90 degrees above the horizontal level. (FIG. 3.) In normal inactive condition the conductive liquid will be at the bottom of the sealed hollowed tube. When the vehicle is subjected to deceleration, the liquid flows up the slope to the top end of the tube. At the top end of the tube there are two contacts that in a normal condition are isolated from one another. When the conductive liquid reaches the top end, it shorts the two contacts and creates a path from one contact to the other, and permits the flow of power from the Brake-Lights line, that is connected to one contact, to the other contact that is connected to the Reverse-Lights line. If the deceleration is above the minimum deceleration required to activate the deceleration sensor, the liquid is captured at the sealed top and the sensor remains engaged. When the deceleration declines below 0.2 G, the liquid slides back to the bottom, and the contact opens between the Reverse-Lights and the Brake-Lights. 
     The same deceleration sensor can be made by using a pendulum or a mass and a spring that measures deceleration of 0.2 G or above. Another way is to use the oil pressure in the braking system is above a given pressure as indication of deceleration. 
     The deceleration sensor is housed in a package or a case. A marking on the package or the case indicates the way to install the deceleration sensor. The marking includes an arrow that should point to the front end of the vehicle when fully installed, and a line indicating the horizontal level. The package or the case is mounted in the vehicle with the horizontal level mark on the deceleration sensor package aligns with the vehicle horizontal level. When installed, the sensor deceleration measuring capability is pointing forward toward the front end of the vehicle. The deceleration sensor is secured to the vehicle by a magnet, screws or adhesive material. 
     The combination of Reverse-Lights and Brake-Lights will demand the attention of a following driver to take the appropriate defensive action when the warning condition exists. 
     In the above configuration, once the lead vehicle is at deceleration below 0.2 G, the Reverse-Light is extinguished, and approaching vehicles are unaware that the vehicle ahead is actually at a full stop and not just applying the brakes. An extra latching circuit using a diode and a relay are used to sustain the warning signal, until the power to the Brake-Lights is removed. The diode is used to insure that only the power from the Brake-Lights line will latch the latching relay and be routed to the Reverse-Lights line and not the other way around. 
     In a different scenario after a collision impact, the lead driver might not have used the brakes or had removed his or her leg from the brake pedal accidentally and the special warning signal is extinguished. To avoid this possibility a second deceleration sensor designed to detect deceleration above 1 G is connected to a one-shot pulse generator that maintains an engaged condition of up to 30 seconds after the one-shot is triggered. Deceleration sensor of 1 G is obtained when the angle of the sensor to the horizontal level is 45 degrees. The one-shot circuit turns on a relay that provides power to the Reverse-Light and the break light for the duration of the one-shot engaged period regardless if the driver ever applied the brakes, or remove the leg from the brake pedal. The line to the Reverse-Lights line, and the line to the Brake-Lights line, are routed via different switching, or are separated by two diodes. FIG.  7  and FIG.  8 . The purpose of the two diodes or the separate switches is to prevent a permanent short between the Reverse-Lights line and the Brake-Lights line. 
     When the vehicle climbs or descents a steep grade, the deceleration sensor engages at a different deceleration value. Climbing, the sensor engages at higher value of deceleration, but it is easier to stop the vehicle going up the grade. Down the grade, the sensor engages at a lower value but this is proper, because the sensor becomes more sensitive and it is harder to stop going down the grade. On a bumpy road going down the grade, false alarms might be initiated. For such off-road conditions, increasing the angle up from the horizontal level can make a correction of the deceleration sensor, to insure proper operation. 
     A relay means an electrical mechanical relay or a solid state relay. G is the earth gravity as a measurement of deceleration or acceleration.