Abstract:
A combined valve stem and pressure gauge that is permanently supported relative to the rim of a pneumatic tired vehicle to indicate by color at all times whether the air pressure in the tire is at a recommended level, or whether the tire is under inflated or over inflated. The invention permits air under pressure to be introduced into the tire to inflate the latter to the recommended level.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     Combined valve stem and pressure gauge. 
     2. Description of the Prior Art 
     A major object of the present invention is to provide a combined valve stem and pressure gauge that permits air under pressure to be introduced into the tire as required, with the valve stem preferably removably supporting a cap on the free outer end thereof, and the invention when the cap is either in place on the stem or removed therefrom visually indicating by color whether the air pressure in the tire is at a recommended level, or whether the tire is under inflated or over inflated. 
     Another object of the invention is to supply a combined valve stem and pressure gauge that is simple and easy to mount on the rim of a vehicle, has simple mechanical structure, can be fabricated from standard commercially available materials, and is sufficiently inexpensive as to encourage the widespread use thereof. 
     A further object of the invention is to furnish valve stems and pressure gauges that are particularly useful on dual pneumatic tired wheel assemblies to assure that each tire is inflated to a recommended pressure to assure equal distribution of the load of the vehicle between the dual tires. 
     Yet another object of the invention is to assure, by visual inspection only, that all tires on a vehicle are inflated to a recommended level, and by so doing obtaining maximum mileage from the tires at a minimum cost. 
     SUMMARY OF THE INVENTION 
     The combined valve stem and pressure gauge includes a tubular rubber jacket that has first and second end portions. The first end portion is so shaped as to sealingly engage an opening in the rim of a vehicle on which a pneumatic tire is mounted or if desired may be secured to an inner tube when the latter is used. A transparent tube is permanently disposed in the jacket, with a first end of the tube serving to hold an apertured end cap in a fixed position in the jacket. A substantial portion of the transparent tube projects outwardly from the jacket, with this portion terminating in a second ring shaped end. 
     An air inlet tube is longitudinally disposed in the transparent tube. The air inlet tube has a first end portion that extends through the apertured end cap and defines an annulus shaped space therewith. The second end portion of the air inlet tube includes a flange and an externally and internally threaded shell, which second end portion is outwardly disposed from the second end of the transparent tube. The shell has a conventional air inlet valve threaded into the interior thereof. 
     The exterior threaded surface of the shell has an opaque internally threaded sleeve mounted thereon that holds the flange in abutting contact with the second end of the transparent tube. The portion of the transparent tube between the second end of the tubular jacket and the adjacent end of the sleeve provides a window through which the colors of the pressure indicating member of the invention is visible. 
     The pressure indicating member includes a central tube that on a first end develops into a head of enlarged transverse cross section. The central tube is slidably mounted on the air inlet tube. First and second elongate, concentric, resilient sleeves that are radially spaced from one another extend towards the end cap. The free end of the first sleeve is secured to the end cap, and the free end of the second sleeve to the air inlet tube. 
     The first and second sleeves and head cooperate to define an air chamber into which air can flow from the tire through an annulus space in the end cap defined in the aperture through which the air tube extends. A helically wound precision spring encircles the first sleeve. The spring has a first end anchored to the end cap and a second end to the head. 
     The second end of the tube develops into an elongate, cup shaped, cylindrical body that has a central band of yellow on the exterior thereof that is of the same width as the window. First and second bands of red are situated on opposite sides of the yellow band. An internally threaded cap is provided that engages external threads on the shell that are outwardly disposed from the sleeve. 
     The tire is inflated in a conventional manner by use of the air inlet valve and air inlet tube. Pressurized air from the tire flows through the annulus into the air chamber to force the pressure indicating member longitudinally away from the end cap. The helical spring tends to restrain such longitudinal movement. 
     As air flows into the confined space the helical spring is tensioned to allow movement of the pressure indicating member. When the yellow band is transversely aligned with the window, the tire is inflated to a recommended pressure. This recommended pressure is the pressure at which the manufacturer of the tire considers best for optimum mileage. If the tire is over inflated a portion of the first red band will show in the window as well as a part of the yellow band. Likewise, if the tire is under inflated all or a part of the second red band will show in the window. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     FIG. 1 is a perspective view of the combined tubeless valve stem and pressure gauge invention mounted on the rim of a pneumatic tired wheel; 
     FIG. 2 is a side elevational view of the invention; 
     FIG. 3 is a first longitudinal cross sectional view of the invention, with the color indicating portion thereof disposed to visually show that the tire is inflated to the recommended pressure; 
     FIG. 4 is a second longitudinal cross sectional view of the invention, with the color indicating portion thereof disposed to visually show that the tire is under inflated; and 
     FIG. 5 is a transverse cross-sectional view of the invention taken on the line 5--5 of FIG. 3. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The invention A as may best be seen in FIGS. 1 and 3 is permanently mounted on an automotive rim C by engaging an opening B in the latter and when so mounted visually indicates by color whether the air in a tire D mounted on the rim is at the manufacturer&#39;s recommended pressure or over or under inflated. 
     The invention A, as best seen in FIGS. 2 and 3, includes an opaque tubular jacket E that has first and second ends 10 and 12. The jacket E adjacent the first end develops into a grooved bead 14 that engages the opening B. Jacket E has an internal body shoulder 16 adjacent the first end 10 thereof. 
     An end cap 18 is provided that seats on the body shoulder 16. The cap 18 includes a neck 20 through which a longitudinal aperture 22 extends. The neck 20 has an external circumferential groove 24 defined thereon. 
     A transparent tube F is provided that has first and second ends 26 and 28, with the first end 26 being in abutting contact with the end cap 18. 
     An air inlet member G is longitudinally disposed within the tube F. The air inlet member includes a first elongate tube 26 that has first and second ends 28 and 30. The second end 30 develops into a second axially aligned tube 32. The second tube 32 on the end most remote from the first tube 26 develops into a flange 34 from which an externally and internally threaded cylindrical shell 36 projects. A spring-loaded externally threaded air inlet valve H of conventional present day design is disposed in shell 36 and in engagement with the internal threads therein. 
     An opaque cylindrical shell J is secured to the second end 28 of the transparent tube F and longitudinally spaced from the second end 12 of jacket E to provide a cylindrical window 38 in the transparent tube F. 
     A pressure indicating member K is longitudinally disposed in the transparent tube F. The pressure indicating member K includes a third tube 40 that is slidably movable on the first tube 26. The third tube F has first and second ends 40a and 40b. The first end 40a develops into a head 42 from which first and second concentric resilient side walls 44 and 46 extend. The second end 40b develops into an elongate cylindrical body 48 that has a circumferential yellow band 50 defined thereon that is the same width as the length of the window F. First and second red bands 52 and 54 are defined on body 48 on opposite sides of red band 50. 
     The free end of the first and second side wall 44 and 46 are secured to the end cap 18 and first tube 26, as may best be seen in FIG. 3. An elongate compressed helical spring 56 encircles the second side wall 54 and has a first end 58 in engagement with groove 24. The first end 58 grips the free end of second side wall 46 to secure the same to end cap 18. A second end 60 of the spring 56 is in engagement with the head 42. 
     The first and second side walls 44 and 46 are resilient and may stretch longitudinally. The first and second side walls 44 and 46 cooperate to define a confined space 62 therebetween that is in communication with an annulus space 64. The first tube 26 is of smaller transverse cross section than the aperture 22 and cooperates to define the annulus space 64 therewith. 
     The valve H permits pressurized air to flow into the interior of the tire D through the first tube 26. The spring 56 at all times tends to prevent the pressure indicating member K moving longitudinally away from the rim C. However, when air flows into the confined space 62 through annulus 64, the spring 56 is deformed longitudinally and the pressure indicating member K moves longitudinally relative to the window 38. The spring is calibrated and is of such strength that when air in the confined space 62 has reached the recommended pressure set by the manufacturer for inflation of the tire D, the body 38 is so disposed that the yellow band 50 thereon is transversely aligned with the window 38. It will be apparent, as viewed in FIG. 3, that if the tire D has excessive air pressure therein the pressure indicating member K will move upwardly to the extend that at least a portion of the red band 52 is visible through the window 38. 
     Likewise, if the tire is underinflated, the spring 56 will contract and move the pressure indicating member K downwardly as viewed in FIG. 3 to the extent that at least a portion of the second red band is visible. The invention A is illustrated as having an internally threaded cap L mounted on the externally threaded portion of the shell 36 that projects outwardly beyond the sleeve J. 
     The use and operation of the invention has been described previously in detail and need not be repeated.