Patent ID: 7251994

Claim:
A tire pressure indicating apparatus comprising: a plurality of concentric cylindrical parts including: a) a base providing an internal female thread and an annular guide groove positioned between opposing inner and outer walls, to inner wall providing an annular inner sealing groove, the outer wall providing an annular outer sealing groove; b) a flexible diaphragm positioned within the guide groove with an annular inner diaphragm wall terminating within the inner scaling groove and an annular outer diaphragm wall terminating within the outer sealing groove; c) a valve body engaged at a proximal end thereof within the base, an annular lip of the valve body securing the inner diaphragm wall within the inner sealing groove; d) an axially movable indicator sleeve positioned between the inner and outer walls of the diaphragm; e) a cover engaged with the base, the cover enclosing the diaphragm, the indicator sleeve and a medial portion of the valve body, an annular lip of the cover securing the outer diaphragm wall within the outer sealing groove; f) a coil spring compressively engaged between to cover and a flange of the indicator sleeve; the inner wall of the base providing a bore joining a central space of the base with the guide groove, thereby exposing one side of the diaphragm to air pressure within the central space of the base and an interior space of the valve body; the apparatus further comprising a pin release engaged within the valve body and extending in adjacency to the female thread in a position for opening a valve threadedly engaged with the female thread; and an air valve engaged within a distal end of the valve body for accepting air flow into the valve body and central space of the base; whereby, with air pressure within the base and valve body superior to atmospheric air pressure, the diaphragm depresses the spring to drive the indicator sleeve into a transparent portion of the cover; and whereby, with air pressure within the base and valve body inferior to atmospheric air pressure, the spring drives the indictor sleeve into an opaque portion of the cover thereby revealing a medial portion of the valve body visible through the transparent portion of the cover.