METHOD OF AND MEANS FOR CONTROLLING TRAFFIC
First Claim
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1. A method of indicating the deviation of vehicle speed from the set speed of a speed zone, comprising the steps of generating an electrical signal proportional in frequency to vehicle speed;
- generating and transmitting from a point external to the vehicle a signal the frequency of which indicates the set speed; and
comparing the vehicle speed indicating signal frequency and the set speed indicating signal to initiate a warning signal when the vehicle speed is outside of the limits of the set speed.
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Abstract
Method of indicating to the driver of a vehicle whether he is exceeding a speed limit as he passes through various areas, the vehicle containing a generator which produces a frequency of voltage in proportion to the vehicle speed and including means which can either be set by the operator or which are set by a radio signal or the like at the area concerned, the device including a comparator which actuates an alarm if the actual speed is outside of the limit set, whether the speed is below or above the set limit.
12 Citations
7 Claims
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1. A method of indicating the deviation of vehicle speed from the set speed of a speed zone, comprising the steps of generating an electrical signal proportional in frequency to vehicle speed;
- generating and transmitting from a point external to the vehicle a signal the frequency of which indicates the set speed; and
comparing the vehicle speed indicating signal frequency and the set speed indicating signal to initiate a warning signal when the vehicle speed is outside of the limits of the set speed.
- generating and transmitting from a point external to the vehicle a signal the frequency of which indicates the set speed; and
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2. The method of claim 1 which includes the additional steps of generating and transmitting an additional signal from a point external to the vehicle;
- and initiating the warning signal upon reception of the additional signal.
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3. Apparatus for indicating deviation of vehicle speed from the set speed of a speed zone, comprising:
- vehicle mounted means for generating an electrical signal proportional in frequency to vehicle speed;
a plurality of resistors;
a switching transistor;
alarm means controlled by the transistor;
a plurality of stationary transmitters, one transmitter being provided for each speed zone, each transmitter having a fixed frequency and different frequencies being provided for different set speeds;
a plurality of relay means, one relay means being associated with each resistor, the relay means being operative so that only one relay is energized at any time, the energized relay placing the corresponding resistor in series connection with the generating means and the transistor;
a vehicle mounted receiver for receiving the signal from the transmitter of the zone in which the vehicle is located; and
a frequency selector circuit responsive to the receiver output for energizing the one of the relay means corresponding to the set speed of the zone.
- vehicle mounted means for generating an electrical signal proportional in frequency to vehicle speed;
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4. Apparatus according to claim 3 further including a second plurality of resistors and a manually controlled switch for placing any one of the second plurality of resistors in parallel connection with the one of the resistors which is in series connection with the generating means and the transistor.
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5. Apparatus according to claim 3 further including a second switching transistor, and an additional relay having a normally closed contact in series connection with the alarm means, at least one of the relay means being operative when energized to disconnect the first transistor from the alarm means and connect the first transistor in series with the additional relay, to connect the alarm means to a power supply whereby the alarm means is operative so long as the first transistor is not conductive, and to place one of the resistors in series connection between the generating means and the second transistor whereby the second transistor is biased to a conducting state energizing the alarm means whenever vehicle speed exceeds a set speed.
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6. Apparatus according to claim 3 further including an additional relay means energized by the selector circuit, the additional relay operating independently of the plurality of relay means and being operative to place an additional variable resistance parallel connection with the one of the variable resistances selected by the plurality of relay means.
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7. Apparatus according to claim 3 further including a plurality of indicator lamps, the means for selecting including means to energize the one of the lamps corresponding to the selected set speed.
Specification