Vehicular tire air pressure measuring system
First Claim
1. An air pressure measuring system for measuring the pressure of air in a tire on a moving vehicle comprising:
- an air pressure transducer mounted on a wheel, said transducer comprising a tubular housing having a first end in communication with the interior volume of a tire on said wheel, a piston slidably positioned within said tubular member, a spring between said piston and a second end of said tubular member, first and second magnetic elements fixed to the first and second ends of said tubular member respectively and a third magnetic element fixed to said piston to move therewith,a magnetic sensor mounted on a vehicle and spaced from the path of rotation of said air pressure transducer, said sensor having an output for providing signals in response to movement of said first, second and third magnetic elements past said sensor, andelectronic processing and display means coupled to said sensor output for measuring the time intervals between passage of said first, second, and third magnetic elements past said sensor, for calculating air pressure from said time intervals, and for visually displaying said air pressure.
2 Assignments
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Accused Products
Abstract
A system for measuring the pressure of air in the tires of a moving vehicle including a wheel mounted transducer, a chassis mounted sensor, and a chassis mounted electronic processing unit for converting sensor signals to tire pressure indications. The transducer includes two fixed magnetic elements and a movable magnetic element positioned between the fixed elements. Tire air pressure moves the movable element against a spring so that its position indicates the pressure. The sensor generates a signal each time a magnetic element passes by it and these signals are coupled to the processing unit. The processing unit measures the time intervals between the passage of the first and second fixed element and calculates pressure from the ratio of time periods. The ratio makes the pressure calculation independent of vehicle speed. The processing unit also multiplexes the outputs of multiple sensors to provide sequential readout of tire pressures and locations.
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Citations
5 Claims
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1. An air pressure measuring system for measuring the pressure of air in a tire on a moving vehicle comprising:
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an air pressure transducer mounted on a wheel, said transducer comprising a tubular housing having a first end in communication with the interior volume of a tire on said wheel, a piston slidably positioned within said tubular member, a spring between said piston and a second end of said tubular member, first and second magnetic elements fixed to the first and second ends of said tubular member respectively and a third magnetic element fixed to said piston to move therewith, a magnetic sensor mounted on a vehicle and spaced from the path of rotation of said air pressure transducer, said sensor having an output for providing signals in response to movement of said first, second and third magnetic elements past said sensor, and electronic processing and display means coupled to said sensor output for measuring the time intervals between passage of said first, second, and third magnetic elements past said sensor, for calculating air pressure from said time intervals, and for visually displaying said air pressure. - View Dependent Claims (2, 3, 4, 5)
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Specification