Low tire pressure warning system

Claim 2

A low tire pressure warning system comprising: a tire pressure sensor constructed to be mounted within a tire on a wheel of a vehicle, the tire pressure sensor including a pressure switch coupled to a transmitter and a battery, and the pressure switch being constructed to connect the battery to the transmitter so as to activate the transmitter when pressure within the tire drops below a low value, the pressure switch and transmitter being located in a sensor enclosure with the pressure switch formed as an integral part of the sensor enclosure, the sensor enclosure hermetically sealed and internally pressurized to the low value; a receiver constructed to be mounted within the vehicle in communication with the transmitter; and a low tire pressure warning indicator coupled to the receiver so as to be activated when the receiver receives a signal from the transmitter.

Claim 3

A low tire pressure warning system as claimed in claim 1 wherein the sensor enclosure includes a flexible wall and the pressure switch includes a fixed electrical contact mounted adjacent an electrically conductive contact on the flexible wall.

Claim 4

A low tire pressure warning system as claimed in claim 1 wherein the flexible wall includes an electrically conductive portion formed integrally with the flexible wall.

Claim 5

A low tire pressure warning system as claimed in claim 3 wherein the sensor enclosure is a can and the flexible wall is a metal cover.

Claim 6

A low tire pressure warning system as claimed in claim 1 wherein the fixed electrical contact includes a metal dome mounted on a circuit board.

Claim 7

A low tire pressure warning system as claimed in claim 5 wherein the transmitter is mounted on the circuit board.

Claim 8

A low tire pressure warning system as claimed in claim 1 wherein the transmitter includes a coded signal generator.

Claim 9

A low tire pressure warning system as claimed in claim 1 wherein the transmitter includes an oscillator for producing a carrier and a pseudo random noise generator connected to the oscillator for modulating the carrier.

Claim 10

A low tire pressure warning system as claimed in claim 8 wherein the oscillator is a crystal oscillator.

Claim 11

A low tire pressure warning system as claimed in claim 8 wherein the receiver includes a pseudo random noise generator similar to the pseudo random noise generator in the transmitter for decoding only valid pseudo random noise coded signals transmitted by the transmitter.

Claim 12

A low tire pressure warning system as claimed in claim 10 wherein the transmitter includes a micropower transmitter.

Claim 13

A low tire pressure warning system comprising: a tire pressure sensor constructed to be mounted within a tire on a wheel of a vehicle, the tire pressure sensor including a pressure switch coupled to a transmitter and a battery, and the pressure switch being constructed to connect the battery to the transmitter so as to activate the transmitter when pressure within the tire drops below a low value; the tire pressure sensor including an internally pressurized sensor enclosure enclosing the pressure switch, the transmitter, and the battery and forming a portion of the pressure switch, the pressure switch including an electrically conductive flexible wall of the enclosure, and a fixed electrical contact mounted adjacent the flexible wall within the sensor enclosure so as to disengage the electrically conductive flexible wall when pressure within the tire drops below the low value and connect the battery to the transmitter, the transmitter being mounted within the sensor enclosure; a receiver constructed to be mounted within the vehicle in communication with the transmitter; and a low tire pressure warning indicator coupled to the receiver so as to be activated when the receiver receives a signal from the transmitter.

Claim 14

A low tire pressure warning system comprising: a tire pressure sensor constructed to be mounted within a tire on a wheel of a vehicle, the tire pressure sensor including a pressure switch coupled to a transmitter and a battery, and the pressure switch being constructed to connect the battery to the transmitter so as to activate the transmitter when pressure within the tire drops below a low value; the tire pressure sensor including an internally pressurized sensor enclosure enclosing the pressure switch, the transmitter, and the battery and forming a portion of the pressure switch, the pressure switch including an electrically conductive flexible wall of the enclosure, and a fixed electrical contact mounted adjacent the flexible wall within the sensor enclosure so as to disengage the electrically conductive flexible wall when pressure within the tire drops below the low value and connect the battery to the transmitter, the transmitter being mounted within the sensor enclosure; a receiver constructed to be mounted within the vehicle in communication with the transmitter; and a low tire pressure warning indicator coupled to the receiver so as to be activated when the receiver receives a signal from the transmitter.

Claim 15

A low tire pressure warning system as claimed in claim 12 wherein the transmitter includes a coded signal generator.

Claim 16

A low tire pressure warning system as claimed in claim 13 wherein the transmitter includes a micropower transmitter.

Claim 17

A low tire pressure warning system comprising: a tire pressure sensor constructed to be mounted within a tire on a wheel of a vehicle, the tire pressure sensor including a pressure switch coupled to a transmitter and a battery, and the pressure switch being constructed to connect the battery to the transmitter so as to activate the transmitter when pressure within the tire drops below a low value, the transmitter includes an oscillator for producing a carrier and a pseudo random noise generator connected to the oscillator for modulating the carrier, the tire pressure sensor including an internally pressurized sensor enclosure enclosing the pressure switch, the transmitter, and the battery with an electrically conductive flexible wall, and a fixed electrical contact mounted adjacent the flexible wall within the sensor enclosure so as to form the pressure switch and disengage the electrically conductive flexible wall when pressure within the tire drops below the low value and connect the battery to the transmitter; a receiver constructed to be mounted within the vehicle in communication with the transmitter for receiving the carrier, the receiver including a pseudo random noise generator similar to the pseudo random noise generator in the transmitter for decoding only valid pseudo random noise coded signals transmitted by the transmitter; and a low tire pressure warning indicator coupled to the receiver so as to be activated when the receiver receives a signal from the transmitter.

Claim 18

A low tire pressure warning system comprising: a tire pressure sensor constructed to be mounted within a tire on a wheel of a vehicle, the tire pressure sensor including a pressure switch coupled to a transmitter and a battery, and the pressure switch being constructed to connect the battery to the transmitter so as to activate the transmitter when pressure within the tire drops below a low value, the transmitter includes an oscillator for producing a carrier and a pseudo random noise generator connected to the oscillator for modulating the carrier, the tire pressure sensor including an internally pressurized sensor enclosure enclosing the pressure switch, the transmitter, and the battery with an electrically conductive flexible wall, and a fixed electrical contact mounted adjacent the flexible wall within the sensor enclosure so as to form the pressure switch and disengage the electrically conductive flexible wall when pressure within the tire drops below the low value and connect the battery to the transmitter; a receiver constructed to be mounted within the vehicle in communication with the transmitter for receiving the carrier, the receiver including a pseudo random noise generator similar to the pseudo random noise generator in the transmitter for decoding only valid pseudo random noise coded signals transmitted by the transmitter; and a low tire pressure warning indicator coupled to the receiver so as to be activated when the receiver receives a signal from the transmitter.

Claim 19

A low tire pressure warning system as claimed in claim 15 wherein the oscillator is a crystal oscillator.