Device for detecting underinflation of a tire and for measuring the kinetic state of a vehicle wheel and the vehicle
First Claim
1. A device for detecting the underinflaion of the tire of a motor vehicle wheel and for measuring the kinetic state of the wheel and of the vehicle from the kinetic state of several wheels, comprising:
- electromagnetic sensor means fixed to said vehicle;
circuit means fixed to said wheel and rotating with said wheel wherein said circuit means periodically passes in front of said sensor means during rotation of said vehicle wheel;
a toothed wheel which rotates with said vehicle wheel and which contains a plurality of teeth with at least one of said teeth being constructed so that the electro-mechanical characteristics of said at least one tooth is modified by pressure drop in one of said tires of said motor vehicle wheels, wherein said toothed wheel generates a signal formed of successive pulses whose period is modified by the variation and the electrical characteristics caused by the pressure drop in one of said tires and by the speed and acceleration conditions of the rotation of said wheel and wherein said electromagnetic sensor detects said tooth wheel generated signal; and
means for computing the values of successive periods of said pulses and for computing the relative variation of said values from several periods wherein said means for computing outputs a signal indicating one of an acceleration, a deceleration and the state of underinflation of one of said tires according to said variation of said value from several periods.
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Accused Products
Abstract
Device for detecting the underinflation of a motor vehicle tire (1) serving also as a device for measuring the kinetic state of the wheel, characterized by the fact that it comprises in combination: a toothed wheel turning with the wheel (1) of the vehicle and whose electrical characteristics of at least one (6a) of the teeth (6) are modified by a pressure drop in one of the tires, an electromagnet (10) fixed to rotate and constituting an electromagnetic sensor in which the toothed wheel (4) generates a signal formed from successive pulses, and a computer (23) which computes the values of the successive periods, and which interprets their variation as an acceleration or deceleration or else as a state of underinflation of the tire according to the behavior of this variation.
13 Citations
6 Claims
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1. A device for detecting the underinflaion of the tire of a motor vehicle wheel and for measuring the kinetic state of the wheel and of the vehicle from the kinetic state of several wheels, comprising:
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electromagnetic sensor means fixed to said vehicle; circuit means fixed to said wheel and rotating with said wheel wherein said circuit means periodically passes in front of said sensor means during rotation of said vehicle wheel; a toothed wheel which rotates with said vehicle wheel and which contains a plurality of teeth with at least one of said teeth being constructed so that the electro-mechanical characteristics of said at least one tooth is modified by pressure drop in one of said tires of said motor vehicle wheels, wherein said toothed wheel generates a signal formed of successive pulses whose period is modified by the variation and the electrical characteristics caused by the pressure drop in one of said tires and by the speed and acceleration conditions of the rotation of said wheel and wherein said electromagnetic sensor detects said tooth wheel generated signal; and means for computing the values of successive periods of said pulses and for computing the relative variation of said values from several periods wherein said means for computing outputs a signal indicating one of an acceleration, a deceleration and the state of underinflation of one of said tires according to said variation of said value from several periods. - View Dependent Claims (2, 3, 4, 5, 6)
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Specification