Composite valve stem

Claim 1

As a new article of manufacture: A pressure-indicating composite valve stem for mounting in the valve stem opening of a tubeless tire rim, comprising: i. a central rigid tubular stem member at least 4 cm. long, the outer end of which is adapted to removably receive a valve core assembly, and the inner end of which terminates approximately at the tire rim as said composite valve stem is mounted in said valve stem opening, said tubular member having a lateral port through the wall thereof for lateral passage of air, ii. a barrel housing about a portion of said tubular member intermediate the ends of said member, said barrel housing being characterized in that it a. terminates at its inner end at least 1.5 cm. from the inner end of said tubular member so that at least 1.5 cm. of the inner end of said tubular member projects free of said barrel housing, b. defines an annular elongated cavity surrounding said tubular member, said lateral port of said tubular member being in communication with said cavity near the inner end thereof, c. has an annular band window of transparent material spaced from the outer end of said barrel housing and located in the outermost three-fifths of the length of said housing, iii. a unitary elastic body a. having an outer portion which annularly surrounds and is firmly bonded both to the exterior surface of the projecting inner end of said tubular member throughout at least most of said projecting length as well as to the exterior surface of at least about one-fifth of the length of said barrel housing adjacent said inner end of said tubular member, the bonding of said elastic body being such as to form a hermetic seal over the junction at said inner end of said barrel housing and said tubular member, b. said elastic body additionally having a neck portion and an enlarged head portion aligned and projecting from the inner end of said tubular member, with a central port through said neck and head portions aligned with the inner end of said tubular member and communicating therewith, said composite valve stem in all portions thereof other than the head portion of said elastic body being of a total diameter and character adaptable to be pressed through said valve stem opening, said elastic body in its portion nearest the inner end of said tubular member and adjacent the neck portion being sufficiently greater in size than said valve stem opening to be subjected to stretching and compression forces as the same is pressed through said valve stem opening but expanding thereafter to its normal size, said neck portion of said elastic body being of a size sufficiently greater than said valve stem opening to remain under such compression as to form a hermetic seal between it and the rim when lodged in said valve stem opening, said head portion of said elastic body being abutted against one side of the tire rim at said valve stem opening when said neck portion is lodged in said valve stem opening, and iv. a pressure-indicating assembly within said cavity defined by said barrel housing, said assembly comprising a. a ring piston annularly about said tubular member, b. mechanical means pressing said piston toward the inner end of said cavity, said mechanical means being yieldable under pressure to allow sliding motion of said piston within at least the inner two-fifths of the length of said cavity, at least the inner end walls of said cavity within which said piston is slidable being hermetically tight and in communication with said lateral port, c. a sleeve-like visual pressure-indicator fixed to said piston and viewable through the window of said barrel housing, said pressure-indicator being color coded to indicate normal and subnormal pressures for glance visual reading through said window, d. movable seal means for sealing against air escape between said slidable piston and said tubular member as well as between said slidable piston and said barrel housing, e. means to stop outward sliding movement of said piston short of passing said window in said housing, f. means to stop inward movement of said piston short of said lateral port in said tubular member, and g. means permitting atmospheric air passage from and to the outer end of said cavity as said piston slides therein.