Signal warning system for motor vehicle

A signal warning system for use with an automotive vehicle as to the application of the vehicle's deceleration in excess of a predetermined speed sensed by the system, thereby continuously flashing a lamp thereof for warning a following car.

BACKGROUND OF THE INVENTION 
This invention relates to a signal warning system and more particularly to 
automatic signal warning system capable of producing a signal to warn 
following vehicles of deceleration in excess of a predetermined rate. 
Large numbers of automobiles commonly follow closely behind each other at 
high rates of speed on today's modern highways and expressways. If one 
automobile decelerates, brakes or backs up in an unexpected manner, the 
following cars often collide in a series of rear end chain reaction 
collisions. These chain reaction collisions result because drivers of the 
following cars fail to anticipate the decleration, stopping or backing up 
of an automobile several cars ahead in the line. By the time a first car 
immediately ahead of a second automobile begins to decelerate, the driver 
of a third car does not have insufficient time in which to react and stop 
his vehicle. Consequently, it is not unusual for a large number of cars to 
be involved in a series of rear end collisions which results in serious 
personal injuries and extensive property damage. 
To employ warning systems on the rear of automobiles is the most common 
form of prior art used to solve the problem described above. The warning 
system lights warn a following driver that the car immediately ahead is 
slowing down or braking. However, the warning signal of a car further 
ahead is obscured by the cars immediately ahead of a following car and can 
not warn a following driver of a sudden slowdown or stop in the line of 
cars further ahead. Also, the signals of the warning systems are energized 
by the slightest pressure on a brake pedal. An over-reaction to the signal 
by following drivers results in an unnecessary amount of sudden breaking 
which lessens the effectiveness of the warning system as a warning of 
rapid deceleration. The effectiveness of the signal warning systen is 
still further reduced since the location and size of the light vary 
greatly from vehicle to vehicle, and oftentimes a tail light is used as 
well as a brake light. 
SUMMARY OF THE INVENTION 
Therefore, it is the main object of this invention to provide an improved 
signal warning system which is readily visible for warning cars several 
positions behind a vehicle that the vehicle is rapidly, decelerating, 
braking or backing up. 
Another object of this invention is to provide a simple, easily operated 
signal warning system which is actuated by deceleration in excess of a 
predetermined rate without incurring false signalling. 
A further object of this invention is to provide a warning signal system 
which is employed by a driver when stopped along a highway and when 
entering heavy or high speed traffic.

DETAILED DESCRIPTION OF THE INVENTION 
Referring to FIG. 1, a basic conceptual model of the fundamental functional 
element of preferred embodiments of this invention is shown, which 
illustrates: a speed sensoring circuit 20 and an ignition sensoring 
circuit 30 are respectively connected to the two input terminals of AND 
gate 10, while the output terminal of AND gate 10 is coupled to a timing 
circuit 40. A cable (not shown) connected to a speedometer is supplied to 
the speed sensoring circuit 20. A signaling circuit 50 is coupled to the 
output terminal of timing circuit 40, thereby causing the lamp thereof to 
flash. 
In FIG. 2, the speed sensoring circuit 20 includes a comparator IC1, a 
variable resistor SVR1, a capacitor and a rectifier. The comparator IC1 
operates as a voltage comparator. It compares the voltage signal from the 
negative terminal thereof, which generates with a variable resistor SVR1, 
with the reference signal from the positive terminal thereof. When the 
voltage signal from the negative terminal of the comparator IC1 
corresponds with the reference signal from the positive terminal thereof, 
the comparator IC1 outputs a low state signal at the output terminal 
thereof. Oppositely, if the two voltage signals do not correspond, the 
comparator IC1 outputs a high state signal. 
The alternating current output from the generator G is supplied to a 
rectifier. The rectifier is simultaneously oriented to one side of 
capacitor C1 and one terminal of resistor R1. One side of capacitor C2 and 
one terminal of variable resistor SVR1 are commoned together to the other 
terminal of resistor R1. The variable resistor SVR1 is connected to the 
negative terminal of comparator IC1 for adjusting and setting the 
predetermined value. A resistor R2 and a resistor R3 are connected in 
series between the positive source and the ground potential. The 
intermediate node 60 is coupled to the positive terminal of comparator IC1 
in order to provide a fixed reference voltage thereat. 
In the ignition sensoring circuit 30 there is a node 61 between the 
ignition coil L2 and the breaker point L3, which is coupled through 
capacitor C5, resistor R14, diode and resistor R20 to the positive 
terminal of the comparator IC4. A resistor R18 and a resistor R19 are 
coupled in series between node 62 and the ground potential. A intermediate 
node 63 is connected to the negative terminal of comparator IC4. A 
capacitor C7 and a variable resistor SVR2 is coupled together to the 
positive terminal of comparator IC4. Variable resistor SVR2 is used to 
allow capacitor C7 to slowly discharge therethrough. Comparator IC4 
functions to compare the voltage at positive terminal to the voltage at 
negative terminal. If the voltage at positive terminal exceeds the voltage 
at negative terminal then there are high state signals outputted from 
comparator IC4. If the voltage at positive terminal is less than the 
voltage at negative terminal then there are low state signals outputted 
from comparator IC4. 
The AND gate 10 whose two input terminals respectively connected to the 
output terminals of speed sensoring circuit 20 and ignition sensoring 
circuit 30 is provided, while the output terminal thereof is coupled to 
node 64. 
The timing circuit 40 is used as a timer as well as an oscillator. 
A resistor R5 interconnects node 64 and node 65. A resistor R6 and a 
capacitor C3 are connected in series between node 65 and the ground 
potential. A diode D5 is reservely coupled between node 65 and the 
negative terminal of comparator IC2. A resistor R7 interconects the 
positive source and the positive terminal of comparator IC2. A series of 
resistors R7 and R8 are connected between the positive source and the 
ground potential. A intermediate node 66 is coupled to the positive 
terminal of comparator IC2. 
The comparator IC2 which functions as a timer, outputs a train of pulses 
whose each duration approximately around 1.1 seconds in high and low 
states thereunder when it is enabled. A diode D16 is reservely provided 
between nodes 67 and 65. A capacitor is connected between node 67 and the 
ground potential. A series of resistors R9 and R10 interconnect the 
positive source and the ground potential and a intermediate node 68 is 
coupled to the positive terminal of comparator IC3. A resistor R12 is 
provided between nodes 66 and 68. A resistor R11 is coupled between nodes 
67 and 68. 
The comparator IC3 which functions as an oscillator, outputs a train of 
pulses, each having a duration of approximately 0.23 seconds in high and 
low states thereunder when it is activated. 
Two input terminals of AND gate 11 are respectively connected to the output 
terminals of comparator IC2 and IC3, while the output terminal of AND gate 
11 is supplied to one of the input terminals of AND gate 12. The AND gate 
12 whose two input terminals respectively supplied to node 64 and the 
output terminal of AND gate 11 is provided, while the output terminal of 
which is coupled to a transistor Q1 via resistor R13. 
A relay Ry interconnects the positive source, a light L1 and the transistor 
Q1 whose collector terminal being coupled. A diode D7 whose cathode 
terminal and anode terminal respectively connected to the positive source 
and the collector terminal of transistor Q1, is provided in parallel with 
the relay Ry. Lead A of the relay Ry can be coupled to a brake light, a 
tail light or a indicating light. 
The operation of signal warning system will now be fully described. While a 
car is being driven at a predetermined speed (i.e., 60 km/hour), the speed 
sensoring circuit 20 and the ignition sensoring circuit 30 are normally 
kept on high and low state at the output terminals thereof, respectively. 
If a speed below 60 km/hour caused by the deceleration is being sensed, 
the ignition sensoring circuit 30 is, accordingly, of high state at the 
output terminal thereof, but the speed sensoring circuit 20 is changed 
into low state at the output terminal thereof so that the timing circuit 
40 is not activated to cause the light L1 to be dimmed. 
As the signal is of high state at the output terminal of comparator IC1 
caused by that the speed above 60 km/hour is being sensed, and the brake 
pedal is depressed, the signal supplied from the output terminal of 
comparator IC4 is of high state to enable the timing circuit 40 and 
results in activating of the transistor Q1 and affecting of the relay Ry, 
thereby causing the light L1 to be continuously flashed. 
In compliance with the statue, the invention has been described in language 
more or less specific as to structural features. It is to be understood, 
however, that the invention is not limited to the specific features shown, 
since the circuits herein disclosed comprise a preferred form of putting 
the invention into effect. The invention is, therefore, claimed in any of 
its forms or modifications within the proper scope of the appended claims, 
appropriately interpreted in accordance with the doctrine of equivalents.