US 5,963,128 AGranted

Remote tire pressure monitoring system

AssigneeSchrader-Bridgeport International, Inc.

InventorStephen McClelland

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Abstract

A system which monitors a vehicle's tire pressures and displays real-time pressure values on a dashboard display while the vehicle is on the road. An electronic unit with pressure sensor, roll switch, reed switch, tilt switch, battery and control electronic, mounted to the valve stem inside each tire uses the pressure sensor to periodically measure the tire pressure, and uses a transmitter to transmit the measured pressure values, via RF transmission, to a dashboard mounted receiver. The receiver controls a display which indicates to the driver the real-time tire pressure in each wheel. the display also indicates an alarm condition when the tire pressure falls below certain predefined thresholds. The pressure values are compensated for temperature changes inside the tire, and also may be compensated for altitude changes.

Claims18

Dependent claims

In a vehicle having at least two wheels with tires mounted thereon, a remote tire pressure monitoring system comprising, for each of said tires:

a pressure sensor for sensing a pressure of said tire, and providing tire pressure measurements accordingly;
a radio transmitter for transmitting said tire pressure measurements via radio transmissions;
a control circuit, connected to said pressure sensor and said radio transmitter, for controlling operation of said pressure sensor and said radio transmitter, including control of a periodicity of operation of said pressure sensor and said radio transmitter;
a roll switch, connected to said control circuit and having at least first and second states, for monitoring a state of motion of said vehicle;
and
a power supply for providing power continuously to said control circuit;
wherein, in response to said first state of said roll switch, said control circuit causes said pressure sensor and said radio transmitter to operate at a first periodicity, and in response to said second state of said roll switch, said control circuit causes said pressure sensor and said radio transmitter to operate a second periodicity that is more frequent than said first periodicity.

4 more elements

In a vehicle having at least two wheels with tires mounted thereon, a remote tire pressure monitoring system comprising, for each of said tires:

a pressure sensor for sensing a pressure of said tire, and providing tire pressure measurements accordingly;
a radio transmitter for transmitting said tire pressure measurements via radio transmissions;
a control circuit, connected to said pressure sensor and said radio transmitter, for controlling operation of said pressure sensor and said radio transmitter, including control of a periodicity of operation of said pressure sensor and said radio transmitter;
a tilt switch, connected to said control circuit and having at least first and second states, for monitoring a mounting state of said tire;
and
a power supply for providing power continuously to said control circuit;
wherein, in response to one of said first and second states of said tilt switch, said control circuit causes said radio transmitter to output an alarm indicative of an unsatisfactory mounting state of said tire.

4 more elements

In a vehicle having at least two wheels with tires mounted thereon, a remote tire pressure monitoring system comprising, for each of said tires:

a pressure sensor for sensing a pressure of said tire, and providing tire pressure measurements accordingly;
a radio transmitter for transmitting said tire pressure measurements via radio transmissions;
a control circuit, connected to said pressure sensor and said radio transmitter, for controlling operation of said pressure sensor and said radio transmitter, including control of a periodicity of operation of said pressure sensor and said radio transmitter;
a magnetically-activated switch, connected to said control circuit and responsive to presence of a magnetic field, for placing said magnetically-activated switch in a first state, wherein, in response to said first state of said magnetically-activated switch, said control circuit causes said radio transmitter to transmit an identification signal uniquely identifying said tire;
a power supply for providing power continuously to said control circuit;
a roll switch, connected to said control circuit and having at least first and second states, for monitoring a state of motion of said vehicle, wherein, in response to said first state of said roll switch, said control circuit causes said pressure sensor and said radio transmitter to operate at a first periodicity, and in response to said second state of said roll switch, said control circuit causes said pressure sensor and said radio transmitter to operate a second periodicity that is more frequent than said first periodicity;
and
a tilt switch, connected to said control circuit and having at least first and second states, for monitoring an angle at which said tire is mounted, wherein, in response to one of said first and second states of said tilt switch, said control circuit causes said radio transmitter to output an alarm indicative of an unsatisfactory mounting state of said tire.

5 more elements

Dependencies are inferred from the claim text.