System for detecting underinflated tire in a rolling vehicle
First Claim
1. An advisory system for detecting and indicating immediately a selected difference in rotational speed of a pair of load bearing wheels of a vehicle comprisingfirst and second signal generating means associated respectively with first and second vehicle wheels, each including wheel speed transducer means coupled to a wheel, for producing a continuous DC voltage wheel speed signal which is proportional in linear relation to the rotational speed of the wheel;
- electric comparator means for producing an output signal responsive immediately to a selected difference between two DC voltage input signals applied thereto;
electrically operated fault signaling means responsive to an output signal from said comparator means;
means applying as input signals to said comparator means a first DC voltage wheel speed signal generated by said first signal generating means, and a second DC voltage wheel speed signal generated by said second signal generating means;
said comparator means producing an output signal to activate said fault signaling means, when one of said wheel speed signals changes by a selected DC voltage increment relative to the other of said wheel speed signals, said one wheel speed signal functioning as a triggering signal and said other wheel speed signal functioning as a reference signal.
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Abstract
The speeds of two wheels are detected by means of wheel speed transducers associated with each wheel, each producing a DC voltage signal proportional to the respective wheel speed. The circuit includes two electric comparators, each having two inputs and one output, each output controlling a fault indicator in the form of an incandescent light. The two inputs for each comparator are the two produced DC voltage signals; and each comparator is identified with one transducer which provides a triggering wheel speed signal, with the other transducer providing a reference wheel speed signal. Sensitivity resistors provide a positive bias on the reference signal input to each comparator. Normally the two wheel speed signals are the same; however, when a triggering wheel speed signal increases a selected amount relative to the reference wheel speed signal, responsive to an underinflated tire, the associated comparator switches to activate the fault light to indicate an underinflated tire.
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Citations
21 Claims
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1. An advisory system for detecting and indicating immediately a selected difference in rotational speed of a pair of load bearing wheels of a vehicle comprising
first and second signal generating means associated respectively with first and second vehicle wheels, each including wheel speed transducer means coupled to a wheel, for producing a continuous DC voltage wheel speed signal which is proportional in linear relation to the rotational speed of the wheel; -
electric comparator means for producing an output signal responsive immediately to a selected difference between two DC voltage input signals applied thereto; electrically operated fault signaling means responsive to an output signal from said comparator means; means applying as input signals to said comparator means a first DC voltage wheel speed signal generated by said first signal generating means, and a second DC voltage wheel speed signal generated by said second signal generating means;
said comparator means producing an output signal to activate said fault signaling means, when one of said wheel speed signals changes by a selected DC voltage increment relative to the other of said wheel speed signals, said one wheel speed signal functioning as a triggering signal and said other wheel speed signal functioning as a reference signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A method for detecting an underinflated load bearing wheel of a vehicle comprising the steps:
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producing first and second DC voltage signals proportional in amplitude, respectively, to the changing rotational speeds of first and second vehicle wheels; feeding said first and second DC voltage signals as two inputs to each of independent first and second comparators; calibrating each of said comparators to produce an output signal when its first input is more positive than its second input; feeding said first voltage signal as a triggering input to said first comparator, and as a reference input to said second comparator; feeding said second voltage signal as a triggering input to said second comparator, and as a reference input to said first comparator; applying a selected positive bias voltage to each of said reference signals, said bias voltage being the equivalent of a wheel speed voltage signal representing the minimum difference in rotational speed to be detected, whereby a triggering signal must exceed its respective reference signal by the magnitude of said bias voltage to produce said comparator output signal; detecting output signals from said comparators as indications that one vehicle wheel is rotating faster than the other because of relative underinflation of the one wheel;
an output signal from said first comparator indicating an increase in rotational speed of, and underinflation of, said first wheel; and
an output signal from said second comparator indicating an increase in rotational speed of, an underinflation of, said second wheel. - View Dependent Claims (20, 21)
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Specification