On-board tire pressure indicating system
First Claim
1. A system for providing inflation pressure information from a rotating pneumatic tire comprising means defining a reference dimension which is of circumferential extent and which rotates with the tire, means, related to inflation of the tire, defining an inflation measurement dimension which is of circumferential extent which rotates with the tire and sensor means including a Hall effect sensor which does not rotate with the tire and which is disposed in sensing relationship to the first-mentioned means and the second-mentioned means, said sensor means further comprising means for sensing via said Hall effect sensor said reference dimension, means for sensing via said Hall effect sensor said measurement dimension, and means for correlating the sensed measurement and reference dimensions to provide inflation pressure information for the tire.
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Accused Products
Abstract
An on-board tire pressure indicating system comprises for each tire of a vehicle, a receiver disposed adjacent the rotating wheel on which the tire is mounted. On the wheel is a transmitter which comprises three magnets, spaced apart in a general circumferential sense, and lying on essentially the same radius. As the wheel rotates, the magnets repeatedly sweep past the receiver, which generates a pulse at the passage of each magnet. Two of the three magnets are disposed in a predetermined fixed circumferential spacing on the wheel. The third magnet is selectively positioned in a circumferential sense relative to the other two magnets in accordance with the pressure in the tire. The time between the two fixed magnet pulses corresponds to a reference measurement dimension while the time between the selectively positioned magnet'"'"'s pulse and the one of the two fixed magnet'"'"'s pulse corresponds to an inflation pressure measurement dimension. The ratio of the two measurement dimensions is essentially independent of the rotational speed of the wheel and tire. The signals from the sensor are supplied to electronic circuitry which performs the ratio of the sensed inflation measurement dimension to the sensed reference measurement dimension, and it is this ratio which is indicative of the actual inflation pressure. The electronics operates on a multiplex basis, sampling each wheel sensor in a repetitive sequence.
26 Citations
14 Claims
- 1. A system for providing inflation pressure information from a rotating pneumatic tire comprising means defining a reference dimension which is of circumferential extent and which rotates with the tire, means, related to inflation of the tire, defining an inflation measurement dimension which is of circumferential extent which rotates with the tire and sensor means including a Hall effect sensor which does not rotate with the tire and which is disposed in sensing relationship to the first-mentioned means and the second-mentioned means, said sensor means further comprising means for sensing via said Hall effect sensor said reference dimension, means for sensing via said Hall effect sensor said measurement dimension, and means for correlating the sensed measurement and reference dimensions to provide inflation pressure information for the tire.
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14. A system for providing inflation pressure information from a rotating pneumatic tire comprising means defining a reference dimension which is of circumferential extent and which rotates with the tire, means, related to inflation of the tire, defining an inflation measurement dimension which is of circumferential extent and which rotates with the tire, and sensor means which does not rotate with the tire and which is disposed in sensing relationship to the first-mentioned means and the second-mentioned means, said sensor means comprising means for sensing said reference dimension, means for sensing said measurement dimension, and means for correlating the sensed measurement and reference dimensions to provide inflation pressure information for the tire, in which said means, related to inflation of the tire, comprises the combination of an elastomeric member disposed in a leakproof manner in a hole in a wheel on which the tire is mounted and a needle passing through a hole in said member and serving to communicate pressure from the tire to produce the inflation measurement dimension, said member having a neck extending from said member into the pressurized zone cooperatively defined by the wheel and tire, and said hole and said needle passing through said neck, and said neck having a sealing contact with respect to the outside of the needle.
Specification