An automatic shut-off air pressure valve for tires, said valve comprised of:
- an inflation valve stem, wherein said inflation valve stem is mounted on an outer wall of a conventional tire rim and in fluid communication with an interior cavity of said tire through an orifice penetrating said tire rim for providing a conduit for receiving supply air from a compressed air source;
- a discharge valve stem, said discharge valve stem located adjacent to said inflation valve stem, wherein said discharge valve stem comprises an interior chamber, said interior chamber defined by a lower plate and an inner wall of said discharge valve, an upper chamber, said upper chamber defined by an upper plate, said inner wall, and said lower plate, and in fluid communication with said interior chamber:
- and wherein said discharge valve vents air from within said interior chamber when said air is in excess of a pre-determined air pressure:
- said disc shaped lower plate of said valve body assembly further comprises a spring, said spring biasing an upper surface of said lower plate against said lower surface of said disc shaped lower plate;
- said spring having one end biased against said upper plate and the other end on said upper surface of said disc shaped lower platean
- an interconnecting means for placing said tire inflation valve stem and said discharge valve stem in fluid communication, wherein said interconnecting means is an orifice defined b an outer wall of said inflation stem and said interior wall of said discharge valve stem;
- and
- a discharge prevention means for preventing discharge of air from said discharge valve stem while said tire is in operation;
- and wherein fluid communication from said interior chamber to the atmosphere through said discharge valve vents is blocked by a valve body assembly when air within said interior chamber is below a pre-determined pressure, and wherein said valve body assembly is comprised of a head, said head having an upper and lower surface, a downwardly extending shaft having a first end opposite a second end, said first end connected to said lower surface, a disc shaped lower plate having an upper and lower surface, said upper surface connected to said second end;
- and wherein said valve body assembly is held in position within said discharge valve stem by an interior wall of said discharge valve stem and said upper plate and said disc shaped lower plate said lower surface of said head rests against said upper surface of said upper plate when fluid pressure in said discharge valve body is not in excess of said spring's rated bias strength.