Tire inflation valve with pressure indicator

Claim 1

A tire inflation valve and air pressure indicating device comprising an elongated rigid main stem having an axial bore extending therethrough and open at its respective inner and outer ends, a normally closed tire valve mounted in the outer end portion of said main stem, an external cylindrical sleeve mounted on the main stem in concentrically spaced relation and in sealed relation to the stem, a piston slidably and sealingly mounted in the space between the stem and sleeve, spring means within the sleeve to bias the piston in one direction, an air chamber in the space between the sleeve and stem in communication with the bore through the main stem thereby communicating air pressure in the tire with the air chamber for moving the piston against the spring means, said sleeve being transparent to enable visual observation of the movement of the piston and graduated scale means on the sleeve associated with the piston to indicate air pressure within the tire, said stem including an inner flange, said sleeve having an inner end seated on the flange and a sealing gasket between the inner end of the sleeve and the flange, and air passages extending radially from the interior bore of the stem to the air chamber immediately outwardly of the inner end of the sleeve, said spring means being a calibrated coil spring between the piston and the outer end of the sleeve.