Digital circuit for conditioning the operation of a motor vehicle upon the tested motor ability of the operator

A digital circuit for the prohibition of operation of a motor vehicle by an intoxicated person may be fabricated by combining an ignition switch with an engine locking and unlocking means, timing means, sensing means and an indication means. The normal ignition circuit of a motor vehicle is interrupted by an engine locking and unlocking means. A timing signal is generated by the timing means in response to signals received from a clock and a sensing means which in turn is responsive to the performance of the operator in a motor ability test such as the ability to maintain a predetermined amount of steady pressure on a brake pedal. If the operator is successfully performing the test, an indication means produces a first cognizable signal which indicates a successful performance. After the operator has successfully performed the test for a predetermined duration as determined by the count stored in a register, a second cognitive signal is produced by the indication means which indicates that the operator is qualified to operate the vehicle. The normal ignition circuit is then completed by the engine locking and unlocking means in response to the timing signal. The motor vehicle may then be started in the conventional fashion.

BACKGROUND OF THE INVENTION 
1. Field of Invention 
The present invention is a digital circuit for prohibiting the improper 
operation of a vehicle by a physically unfit operator and specifically 
concerns a circuit for prohibiting the improper operation of a vehicle by 
such an unfit operator in which a steady control task is imposed on the 
operator for a designated period of time as a means of evaluating his 
fitness to operate the vehicle. 
2. Description of the Prior Art 
The operation of a vehicle, such as an automobile, requires that the 
vehicle operator be in a mentally and physically stable condition at all 
times. The ability of a vehicle operator to operate a vehicle is affected 
by the influence of alcohol, overwork, imperfect health, drugs, and other 
temporarily disabilitating agents. The operation of a vehicle under such 
mentally and physically abnormal conditions is extremely dangerous to the 
person and property of both the operator and the public at large. Devices 
for determining the unfitness of such operators to operator a vehicle, and 
for prohibiting the operation of the vehicle involved, has been proposed 
in the past. In conventional devices of this type, the vehicle operator is 
given, as a test, appropriate tasks to perform before starting the vehicle 
into motion. The engine may be started only if the operator shows a 
sufficient response to the test. Conventional tasks have required the 
demonstration of an ability to perform simple calculations, tasks which 
test reflex characteristics or other movement reactions. Among such tasks 
used for testing, it is known that a steady control task is able to 
relatively accurately evaluate the fitness of a vehicle operator, and that 
is is particularly suited for the detection of temporary disability due to 
the influence of alcohol or other similarly intoxicating drugs. The term 
"steady control task" refers to a task which requires the continuous 
maintenance of a designated exertion of a bodily force or position for a 
predetermined period of time by the vehicle operator, such as, for 
example, the maintenance of a uniform foot pressure on an operating pedal, 
such as a brake, clutch, or gas pedal. 
In conventional circuits employing a steady control task, evaluation of 
force to determine whether it is within the acceptable range is extremely 
complicated and the evaluating circuit typically requires a complex 
frequency measuring circuit and other such analysis and disposition 
circuits. This increases the cost of the system, and also increases the 
number of possible sources of system malfunction. The mandatory 
characteristics required in a device, which prohibits the improper 
operation of a vehicle due to temporary operator disability, is consistent 
and uniform performance, and high reliability. It is clear that the main 
problem for this type of device is that since its main function is to 
selectively disable the operation of the vehicle and since the evaluating 
device must be used in order to start the engine, such a device must have 
an extraordinarily high degree of reliability. What is needed then is a 
steady control task apparatus or circuit for prohibiting the improper 
operation of a vehicle due to temporary disability of the vehicle 
operator. The device must be characterized by simplicity, low cost and a 
high degree of reliability. 
BRIEF SUMMARY OF THE INVENTION 
The present invention is a digital circuit for prohibiting operation of a 
vehicle by a person failing to perform a predetermined motor ability test. 
The present invention comprises an ignition switch, an engine locking and 
unlocking means, a clock, a timing means, a sensing means, a counting 
means and a logic indication means. The ignition switch is coupled to a 
source of electrical power. The engine locking and unlocking means is 
coupled to the ignition switch and is employed for selectively coupling a 
starting signal to the vehicle in response to an indicator signal. The 
timing means is coupled to the engine locking and unlocking means and 
generates a plurality of validity signals in response to coincidence 
between a performance signal and the clock signals. The sensing means is 
coupled to the timing means and generates the performance signal in 
response to the performance of the person on the selected motor ability 
test. The counting means accumulates the plurality of validity signals. 
Finally, the logic indication means is coupled to the timing means and 
counting means, and generates at least one indicator signal in response to 
the plurality of validity signals and the accumulated count within the 
counting means. The timing means of the present invention may generate the 
validity signal according to the success of the person in performing a 
steady control task for a predetermined time duration or count. 
The method of the present invention is a circuit for conditioning the 
operation of a motor vehicle upon the performance of the vehicle operator 
on a motor ability test comprises the steps of sensing the force exerted 
by the vehicle operator in a steady control task. The duration of time in 
which the force is continually maintained within a predetermined range is 
measured by storing a count from a coincidence clock in a register or 
counting means. The coincidence clock generates a count whenever the force 
is maintained within a predetermined range during a clock interval. A 
plurality of cognizable signals indicating that the force is being 
maintained with in the predetermined range and for a predetermined 
duration is generated. An indicator signal used to actuate an engine 
locking means for selectively permitting conventional initiation of the 
motor vehicle is then generated when the motor ability test is 
successfully completed. 
The method of the present invention includes the case wherein the step of 
measuring the duration of time includes counting the plurality of 
cognizable signals and wherein the step of generating the validity signal 
includes terminating the generation of the plurality of cognizable signals 
and comparing the number of counted cognizable signals with a 
predetermined reference number to generate the indicator signal when the 
counted number and reference number match. Otherwise, the count of 
cognizable signals is reinitialized.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The present invention is a circuit for prohibiting the improper operation 
of a vehicle by a temperarily disabled vehicle operator. The circuit 
contains a sensing means which detects as an electronic on/off signal, a 
task performed by the vehicle operator in which the operator continuously 
maintains a designated holding force for a predetermined period of time. A 
timing means generates, according to the on/off signals of the sensing 
means, a plurality of validity signals during the time in which the 
designated holding force is maintained. The counting means accumulates the 
counts. The logic indication means generates an indicator signal when the 
accumulated count reaches a predetermined duration. An engine locking and 
unlocking means closes the normally open conventional ignition circuit to 
permit starting of the vehicle. The indication means may include a 
cognitive feedback signal to the vehicle operator both as to the status of 
his performance during the test as well as his ultimate successful or 
unsuccessful performance. 
The present invention is particularly advantageous in that: (1) the holding 
force employed in the steady control task is detected as an electronic 
on/off signal; (2) the timing means is a circuit which is activated 
according to this on/off signal; and (3) the locking and unlocking means 
is activated to permit operation of the vehicle only when the vehicle 
operator has satisfactorily performed the steady control task for a 
predetermined period of time. The present invention and its various 
embodiments may be better understood by referring to FIG. 1. 
FIG. 1 illustrates one embodiment of the present invention. Movable contact 
12 of sensing means 10 may be coupled to one of the input terminals of an 
and gate 18. The input terminal of and gate 18 is supplied with voltage 
from a positive terminal of a battery through a resistor 19. When sensing 
means 10 is in an "off" state, an input signal is received by and gate 18. 
When sensing means 10 is in an "on" condition, in which movable contact 12 
has made contact with one of fixed contacts 14a or 14b, and gate 18 is 
grounded and the input signal is interrupted. The other input terminal of 
and gate 18 is coupled to a pulse generator or clock 20 which sends clock 
pulses possessing a fixed period to and gate 18. Clock 20, which contains 
a universally known oscillating circuit and frequency dividing circuit, 
sends one pulse every few seconds, chosen according to design choice, to 
one of the input terminals of and gate 18. The output of and gate 18 is 
coupled to a counter 22. In the embodiment shown in FIG. 1, counter 22 is 
comprised of a well known binary counter using multiple flip-flops coupled 
serially in four states, FF1, FF2, FF3 and FF4. Counter 22 counts the 
clock pulses generated by clock 20 while and gate 18 is receiving an input 
signal from sensing means 10. 
The output of and gate 18 is also coupled to an indicator 26 capable of 
producing a cognizable signal through another and gate 24. Indicator 26 
typically is comprised of an incandescent lamp which is installed within 
the operator's vision. The vehicle operator is able to observe the 
flashing of indicator lamp 26 while he is successfully performing the 
constant task test. A reset circuit 30, well known to the art, is coupled 
to and gate 24 through a change over circuit 28 comprised in turn of two 
flip-flops. Before the steady control task is performed, reset circuit 30 
causes terminal 28a of changeover circuit 28 to send out an output signal. 
This condition continues until a changeover or validity signal, as 
described below, is fed into changeover circuit 28. Furthermore, the 
output voltage from alternator 32 is coupled through an inverter 33 to a 
third input terminal of and gate 24. Before the engine of the vehicle is 
started, alternator 32 has no output voltage as a result, and gate 24 
receives an input signal through inverter 33. Accordingly, during the 
successful performance of the steady control task, and gate 24 causes 
indicating lamp 26 to flash every time an output signal is generated from 
and gate 18. By watching indicating lamp 26 and counting the number of 
times it flashes, the vehicle operator is able to determine the number of 
clock pulses sent from clock 20 to counter 22 while he is successfully 
maintaining the predetermined amount of force as measured by sensing means 
10. 
One example construction of the sensing member 10 is shown in FIG. 2 
wherein like reference numerals are applied to like elements or parts. 
As shown, a metallic casing 200 forms at the lower end a fluid pressure 
conducting pipe 202 having male threads 204 therearound and provided with 
a flare coupling 206 for introduction of the fluid pressure. This fluid 
pressure or oil-hydraulic pressure conducting pipe 202 is communicated 
with a fluid pressure chamber 208 defined by a rubber made diaphragm 210 
which is supported at the lower side by a support plate 212 in chamber 208 
while being sandwitched of its circumferential portion between casing 200 
and a metallic bushing 214. On metallic bushing 214, is securely supported 
on electrode 216 through an insulator 218, which electrode 216 extends 
into an upper chamber 220 defined above diaphragm 210. FIG. 3 shows the 
position of electrode 216 wherein its lower end is spaced a predetermined 
distance from diaphragm 210 as no fluid pressure acts in chamber 208. 
At the lower end of electrode 216, is supported a radially extending fixed 
contact element 222 formed integral with electrode 216. 
In chamber 220 above diaphragm 210, is provided a movable contact element 
224 formed integral with diaphragm 210. This movable contact 224 is in the 
shape of a bottomed cylinder positioned as surrounding above fixed contact 
element 222, and is composed of a cylindrical portion with the bottom 
being secured to diaphragm 210, and a cap-like disc 226 having a central 
opening 228 through which electrode 216 extends. By means of a spring 230 
disposed between a washer 232 and disc 226, both movable contact 224 and 
disphragm 210 are biased in the direction to compress fluid pressure 
chamber 208. Washer 232 is disposed in such manner as to make electrical 
contact with part of bushing 214. 
Diaphragm 210 is normally urged by spring 230 through movable contact 224 
in the direction to compress chamber 208, however diaphragm 210 is 
restrained of its further downward movement beyond the position shown. 
Support plate 212 forms apertures 212a for communication of fluid pressure 
in chamber 208. Casing 200 is caulked around its upper circumference 200a 
thereby to secure bushing 214. 
It is arranged that when diaphragm 210 is in its normal position without 
deformation as shown while fluid pressure in chamber 208 is maintained 
below a predermined level, fixed contact element 222 is in contact with 
the lower side surface of disc plate 226. 
This sensing member will operate as follows. 
When fluid pressure to be sensed is fed into chamber 208 through conducting 
pipe 202, fixed contact element 222 will remain in contact with disc plate 
226 under the influence of spring 230 biasing diaphragm 210 into the 
position shown, until the fluid pressure attains a predetermined value. 
Thus, a circuit is made through electrode 216, fixed contact element 222, 
disc plate 226, spring 230, washer 232, bushing 214 and casing 200, so 
that sensing member 50 is in the state of "on". 
When the fluid pressure within chamber 208 exceeds the predetermined level, 
diaphragm 210 is deflected upward against spring 230 to move movable 
contact element 224 upward, thus disc 226 is moved away from fixed contact 
element 222 so that sensor now issues an "off" signal. 
As the fluid pressure further increases to exceed a further predetermined 
value, the deflection of diaphragm 210 will increase accordingly so that 
bottom of cylindrical portion 224a integral with diaphragm 210 will come 
into contact with electrode 216, thus the output signal from sensor will 
again become "on". 
Hence it is possible to provide"off" signals as long as the fluid pressure 
is within a predetermined range, and "on" signals when the fluid pressure 
is otherwise. 
The contents of counter 22 appear as one input to and gate 35. In the 
embodiment shown in FIG. 1, the outputs of flip-flops FF2 and FF4 are 
directly coupled to the input terminals of and gate 35, while the output 
of FF3 is coupled to one input terminal of and gate 32 through an inverter 
34. Accordingly, it is seen that and gate 35 will generate an output 
signal when the binary value of the contents of counter 22 is 1010 or 
1011. Clearly, any other number may be chosen by appropriately configuring 
the connection between counter 22 and and gate 35. A binary value of 
"1010" indicates a decimal value of 10 and a binary value of "1011" 
indicates a decimal value of 11. Thus, these binary values indicate that 
either 10 or 11 pulses have been sent from clock 20 to counter 22. The 
number of pulses sent to counter 22 is 9 or less or 12 or more, no output 
is generated by and gate 35. As will be described below, unless the 
vehicle operator terminates the constant task performance test when the 
count is either 10 or 11, the counter is reset to its initial state 
without the production of a validity signal and the constant task test 
must be attempted again. 
The output terminal of and gate 35 is coupled to one of the input terminals 
of and gate 36. The other input terminal of and gate 36 is coupled to 
sensing means 10 through an inverter 38. When sensing means 10 is 
generating an "off" signal, a false signal is coupled to and gate 36 
through inverter 38. Only when sensing means 10 is generating an "on" 
signal, will and gate 36 receive a true signal through inverter 38. When 
the vehicle operator terminates the steady control test, sensing means 10 
is switched "on," and and gate 36 will receive a true input signal. 
Accordingly, if the vehicle operator terminates the steady control test 
and the number of pulses registered by counter 22 is 10 or 11, the output 
signal generated by and gate 35 will also be true. Thus and gate 36 will 
generate a validity signal. The output terminal of and gate 36 is coupled 
to changeover circuit 28. Changeover circuit 28 switches its output signal 
from terminal 28a to 28b and responds to a true input signal from and gate 
36. Thus, and gate 24 will generate a false output and lamp 26 will remain 
extinguished. 
Output terminal 28b is coupled to one input terminal of and gate 40. 
Furthermore, the other input terminal of and gate 40 is coupled through 
inverter 33 to alternator 32. The output terminal of and gate 40 is 
coupled to a relay circuit 42 which forms an engine locking means and may 
include a thyristor, resistor and other well known buffer circuitry to 
translate the signal from and gate 40 at an appropriate form for use in 
relay circuit 42. Additional modifications and alterations may be made in 
order to couple the logic state output of and gate 40 to circuit 42 
according to principles well known to the art. When a true output is 
generated by and gate 40, a relay coil 44 is energized and a normally open 
relay contact 46 is switched "on". Relay contact 46 of relay circuit 42 is 
interposed between the ignition switch 48 and starter motor 50. Circuit 42 
will prevent the starting of the engine as long as no true output is 
generated by and gate 40. The output of and gate 40 is also coupled to an 
indicator 52, typically an incandescent lamp. And gate 36 has an output 
indicative of the contents of counter 22 at the time at which the vehicle 
operator terminates the steady control test. If the test has been 
terminated at the predetermined count, and gate 36 will generate a true 
output, otherwise the output of and gate 36 is false. 
After the engine has been started in the conventional manner, alternator 32 
generates a disabling signal which is coupled to and gates 24 and 40 
through inverter 33. The disabling signal will close both gates. 
The output of sensing means 10 is coupled to the reset terminal of each 
flip-flop, FF1, FF2, FF3 and FF4 of counter 22 via a delay circuit 54. 
Delay circuit 54 has a short time delay, such as approximately one tenth 
to two tenths of a second and is faster than the normal reaction times of 
the vehicle operator. Yet the time delay of circuit 54 is substantially 
greater than any of the logic response times within the circuit shown in 
FIG. 1. When sensing means 10 sends out an "on" signal, such as when the 
vehicle operator terminates the test, the contents of counter 22 are 
cleared after the delay time has elapsed. This delay time is necessary in 
order to insure that there is sufficient time for and gate 36 to test the 
contents of counter 22 through and gate 35. It will be noted that when the 
vehicle operator is unable to maintain the designated holding force during 
the steady control task, thereby causing movable contact 12 of sensing 
means 10 to make contact with one of fixed contacts 14a or 14b, the 
contents of counter 22 will automatically be reset requiring the 
reinitiation of performance on the steady control task. 
The operation of the circuit as shown and described in FIG. 1 can be 
understood as follows. Before the engine is started, contact 46 of engine 
locking circuit 42 is in an "off" or open position. Thus, even if ignition 
switch 48 is turned to the "start" position, no current is supplied to 
starter motor 50 and it is impossible to start the engine. Furthermore, 
reset circuit 30 has sent a reset signal to changeover circuit 28 and the 
contents of counter 22 have been reset to 0000. 
Under these conditions, when ignition switch 48 is turned to a position 
which activates the circuit of FIG. 1, each of the devices are supplied 
with a source of electrical current and clock 20 begins its internal 
oscillations. The vehicle operator applies a foot pressure to the brake 
pedal and controls the foot pressure such that lamp 26 begins to flash at 
intervals equal to the period of clock pulses from clock 20. The force of 
the vehicle operator's foot is detected by sensing means 10. Maintaining 
movable contact 12 of sensing means 10 in an "off" state causes sensing 
means 10 to send out an "off" signal. 
Successful performance of the steady control task as reflected in an "off" 
signal from sensing means 10 supplies and gate 18 with an input signal. 
The clock pulses from clock 20 are then counted by counter 22. The 
registration of counts in counter 22 is indicated by lamp 26 through gate 
24, so that the vehicle operator is able to confirm the successful 
performance of his steady control test. If the steady control holding 
force of the vehicle operator changes, causing sensing means 10 to be 
switched "on," counter 22 is reset and the test must be reinitiated. 
The vehicle operator is presented with the task of counting the number of 
times indication is made by lamp 26, that is the number of pulses counted 
by counter 22, until a designated value is reached. In the embodiment 
shown in FIG. 1, the number of counts has been arbitrarily chosen at 10 or 
11. The vehicle operator must count the number of times indicator lamp 26 
flashes as well as applying a steady force to the brake pedal. The number 
of flashes of indicator 26 has reached a designated number, the vehicle 
operator terminates the steady control test. Termination of the steady 
control test causes sensing means 10 to send out an "on" signal. This 
signal is sent to and gate 36. 
And gate 36 also receives a signal based on the contents of counter 22 at 
this time. Counter 22 is not reset by virtue of the delay introduced by 
delay circuit 54. And gate 36 generates an output signal only if the 
contents of counter 22 have a decimal value of 10 or 11. Thus, contact 46 
of engine locking circuit 42 is switched "on" and is maintained in this 
position. Since lamp 52 is lit at this time, the vehicle operator is able 
to determine that the results of his performance on the steady control 
task were favorable. Under these conditions, if the vehicle operator turns 
ignition switch 48 to the starter terminal, he may operate starter motor 
50 and start the engine in the conventional fashion. After the engine has 
started, alternator 32 generates an output voltage thereby closing and 
gates 24 and 40. Thus, lamps 26 and 52 are extinghished. 
It would also be possible with the present invention to positively 
eliminate the improper operation of the vehicle by requiring the vehicle 
operator to perform a more complex calculating operation, in which he may 
count the number of flashes of an indicating lamp during each of several 
steady control tasks in which he must continuously maintain a 
predetermined holding force for a predetermined duration. 
Indicators 26 and 52 may be constructed with red or green incandescent 
lamps, with warning buzzes or any other cognizable signal. Furthermore, it 
would also be possible to construct sensing means 10 as a load cell 
installed in the brake or clutch system. Finally, an engine locking 
circuit could also be constructed such that it controls the supply of 
current to the ignition coil rather than the starter motor as shown in 
FIG. 1. 
Many further embodiments and modifications may be made to both of the 
embodiments of the present invention as shown in FIG. 1 without departing 
from the spirit and scope of the present invention.