Tire pressure sensor

Abstract

A tire pressure monitoring and reporting instrument is mounted within a valve stem and has a valve cap. A single circuit can be provided having an LED, a sounder, a battery and a switch. A dual stage system, or a continuously variable system can be implemented by using a dual stage pressure switch or a continuously variable pressure switch. The battery may be housed within the cap and electrical contacts between the cap and stem allow discontinuation of the circuit or changing of the battery.

1 . 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 in open circuit in series;    b. a valve stem cap adapted to fit on the valve stem and having a valve stem cap electrical contact; wherein upon installation of the valve stem cap, the valve stem electrical contact completes the open circuit in series forming a closed circuit in series;    c. a battery in series with the circuit for powering the circuit;    d. a pressure switch in series with the circuit having a low resistance when the circuit is completed by the pressure switch and having 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 pressure switch opens the circuit.    
     
     
         2 . The device of  claim 1  wherein the battery is located within the valve cap.  
     
     
         3 . The device of  claim 1  wherein both the battery and the sounder is located within the valve cap.  
     
     
         4 . The device of  claim 1  wherein the pressure switch is two-stage and produces two stage resistance leading to two levels of warning sound corresponding to preset levels of air pressure.  
     
     
         5 . The device of  claim 1  wherein the pressure switch is continuously variable and produces continuously variable resistance leading to continuously variable levels of warning sound corresponding to air pressure.  
     
     
         6 . The device of  claim 1  wherein the pressure switch is in the valve stem.  
     
     
         7 . The device of  claim 1  wherein the pressure switch is a variable resistance pressure switch.  
     
     
         8 . The device of  claim 1  wherein the pressure switch is a discrete resistance pressure switch.  
     
     
         9 . A tire pressure monitoring device comprising: 
 a. a valve stem mountable on the tire; wherein the valve stem has a pair of electrical contacts in open circuit in series;    b. a valve stem cap adapted to fit on the valve stem and having a valve stem cap electrical contact; wherein upon installation of the valve stem cap, the valve stem electrical contact completes the open circuit in series forming a closed circuit in series;    c. a battery in series with the circuit for powering the circuit;    d. a pressure switch in series with the circuit having a low resistance when the circuit is completed by the pressure switch and having an infinite resistance when the pressure switch opens the circuit;    e. a lamp in series with the circuit and lighting when the circuit is completed by the pressure switch, and remaining inactive when the pressures switch opens the circuit.    
     
     
         10 . The device of  claim 9  wherein the battery is located within the valve cap.  
     
     
         11 . The device of  claim 9  wherein both the battery and the lamp are located within the valve cap.  
     
     
         12 . The device of  claim 9  wherein the pressure switch is two-stage and produces two stage resistance leading to two levels of warning lamp brightness corresponding to preset levels of air pressure.  
     
     
         13 . The device of  claim 9  wherein the pressure switch is continuously variable and produces continuously variable resistance leading to continuously variable levels of lamp brightness corresponding to air pressure.  
     
     
         14 . The device of  claim 9  wherein the pressure switch is in the valve stem.  
     
     
         15 . The device of  claim 9  wherein the pressure switch is a variable resistance pressure switch.  
     
     
         16 . The device of  claim 9  wherein the pressure switch is a discrete resistance pressure switch.  
     
     
         17 . 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 in open circuit in series;    b. a valve stem cap adapted to fit on the valve stem and having a valve stem cap electrical contact; wherein upon installation of the valve stem cap, the valve stem electrical contact completes the open circuit in series forming a closed circuit in series;    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 wireless transmitter receiving tire pressure data in the form of circuit voltage across the pressure switch and transmitting tire pressure data to a wireless receiver.    
     
     
         18 . The device of  claim 17  wherein the battery is located within the valve cap.  
     
     
         19 . The device of  claim 17  wherein both the battery and the wireless transmitter are located within the valve cap.  
     
     
         20 . The device of  claim 17  wherein the pressure switch is two-stage and produces two stage resistance leading to two levels of wireless transmitter readings corresponding to preset levels of air pressure.  
     
     
         21 . The device of  claim 17  wherein the pressure switch is continuously variable and produces continuously variable resistance leading to continuously variable levels of wireless transmitter readings corresponding to air pressure.  
     
     
         22 . The device of  claim 17  wherein the pressure switch is a variable resistance pressure switch.  
     
     
         23 . The device of  claim 17  wherein the pressure switch is a discrete resistance pressure switch.  
     
     
         24 . The device of  claim 17  wherein the pressure switch is in the valve stem.