Patent ID: 6817235
Filing Date: 2004-11-16
Classification: B60C

Abstract:
A pneumatic tire air pressure monitoring device comprising:a. a valve stem mountable on the tire; wherein the valve stem has a pair of electrical contacts, a first valve stem electrical contact in series with a second valve stem electrical contact; b. a valve stem cap adapted to fit on the valve stem and having a pair of valve stem cap electrical contacts, a first valve stem cap electrical contact in series with a second valve stem cap electrical contact; wherein upon installation of the valve stem cap, the first valve stem electrical contact makes electrical connection with the first valve stem cap electrical contact and the second valve stem electrical contact makes electrical connection with the second valve stem cap electrical contact, wherein the circuit is interrupted when the first valve stem electrical contact is separated from the first valve stem cap electrical contact and the second valve stem electrical contact is separated from the second valve stem cap electrical contact, wherein the circuit restored when the first valve stem electrical contact is connected to the first valve stem cap electrical contact and the second valve stem electrical contact is connected to the second valve stem cap electrical contact, c. a battery in series with the circuit for powering the circuit; d. a pressure switch in series with the circuit having a lower resistance when the circuit is completed by the pressure switch and having an infinite resistance when the pressure switch opens the circuit; e. a sounder device in series with the circuit and producing sound when the circuit is completed by the pressure switch and remaining inactive when the pressures switch opens the circuit.