Valve cap assembly

A valve cap assembly for being attached to an air valve and removably covering an end of the air valve includes a hoop, a cap, and an arched tether connecting the hoop and the cap. The hoop attaches the valve cap assembly to the air valve. The cap removably covers the end of the air valve to protect the end of the air valve. Both the hoop and the cap form a dependable interference fit between the hoop or cap and the valve stem to retain the hoop on the valve stem and to retain the cap covering the end of the air valve on the air valve. The cap includes one or more longitudinal protrusions that form the interference fit.

FIELD OF THE DISCLOSURE

The disclosure relates generally to caps for protecting the exposed ends of air valves on pneumatic tires, and in particular, to a valve cap assembly that removably attaches the cap to the air valve.

BACKGROUND OF THE DISCLOSURE

An air valve for a pneumatic tire of a bicycle, automobile, or other wheeled vehicle is used to inflate the tire through a hollow stem extending from the tire to an exposed end. A valve disposed in the end of the stem is opened to flow pressurized air into the tire and then re-closed to retain tire pressure.

An air valve is provided with a removable cap placed over the upper end of the stem to protect the valve during use of the wheeled vehicle. The cap also prevents road dirt and debris from interfering with proper operation of the valve.

Some bicycle tires are typically inflated to 5.5-9.0 Bar (80-130 PSI), which requires at least weekly filling during the riding season. The cap must be removed to inflate the tire. Loss of the cap after inflating the tire is common, whether by misplacing the cap or by forgetting to place the cap back on the air valve.

Caps that are tethered to a wheel spoke or to the air valve of a bicycle are available that reduce the risk of loss of the cap after inflating the tire. See, for example, the tethered cap device disclosed in Wilson, U.S. Pat. No. 5,195,561. The Wilson cap has protrusions that interact with external threads on the air valve. Protrusions can extend into the valleys between adjacent threads and so make the cap difficult to remove from the air valve.

Yet other known caps may come off the valve stem while the bicycle is being ridden, or have tethers that are too short and stretching the tether requires so much force that the entire cap device may be pulled off the air valve. Thus there is a need for an improved removable valve cap assembly that more reliably retains the cap and the valve cap assembly on the valve stem when riding the bicycle, while still allowing easy placement of the cap on the air valve and easy removal of the cap off the air valve.

SUMMARY OF THE DISCLOSURE

Disclosed is a valve cap assembly that is attached to an air valve and includes a cap that removably covers an end of the air valve of a pneumatic wheeled vehicle, a hoop that attaches to the air valve, and a tether joining the cap and the hoop. Both the cap and the hoop include interference features that dependably retain the hoop and cap on the air valve.

The cap includes protrusions that form interference fits with the air valve while the cap is over the end of the air valve. The protrusions extend in a longitudinal direction along the air valve for a distance substantially greater than the interference.

The interference features are deformed by the valve stem to generate forces applied by the cap and the hoop to the stem that resist axial movement of the cap and hoop along the valve stem.

Embodiments of the tether include an arch or curved portion that extends along a side of the air valve when the cap is placed over the end of the air valve but can be stretched or “flattened” to enable the cap to be removed from the air valve or reinstalled onto the air valve.

Other objects and features of the disclosure will become apparent as the description proceeds, especially when taken in conjunction with the accompanying drawing sheets illustrating one or more illustrative embodiments.

DETAILED DESCRIPTION

FIGS. 1-4illustrate a valve cap assembly10in accordance with this disclosure, andFIGS. 5-7illustrate the valve cap assembly attached to a Presta type air valve V.

The valve cap assembly10includes a cap12, a hoop14, and a flexible tether16connecting the cap and the hoop. The illustrated valve cap assembly is formed as a one-piece, homogeneous body from a thermoplastic elastomer such as a thermoplastic polyurethane. The elastomer has sufficient elasticity to enable the cap and hoop to attach to and be retained on the air valve by interference fits with the air valve as described in more detail below.

The hoop14slides on the air valve V to attach the valve cap assembly10to an air valve.FIG. 5illustrates the hoop attaching the valve cap assembly to an air valve V of a bicycle. The tether16retains the cap12with the hoop even when the cap is not placed over the end of the air valve.

FIGS. 6 and 7illustrate placing the cap12on the end of the air valve V. The cap12is a hollow member having an open end that receives the end of the air valve into the cap as shown inFIG. 6. The tether16enables the cap and hoop to be selectively placed closer apart and further apart from one another as needed to move and place the cap on the air valve or to remove the cap from the air valve.

FIG. 7illustrates the cap12covering the end of the air valve V. The cap receives a sufficient length of the air valve within the cap to secure the cap to the end of the air valve. The cap when covering the end of the air valve is spaced closely from the hoop14help resist entry of water, road dirt and the like into the cap.

Attachment of the valve cap assembly to the air valve V is described next.

To attach the valve cap assembly10to the air valve V, the hoop14is placed over the end of the air valve. The cap12is then placed over the hoop and the cap is used to push the hoop along the air valve until the end of the air valve is fully received inside the cap. This positions the hoop in its final installed position along the air valve as shown inFIG. 5. As will be explained in more detail below, both the cap and hoop have interference features that help hold the cap and hook to the air valve with interference fits while the bicycle is being ridden.

A detailed description of the valve cap assembly10is provided next.

FIGS. 8-10illustrate the hoop14. The hoop includes a tubular body18extending along and axisymmetric about an axis20that defines a radial direction perpendicular to the axis and a longitudinal direction parallel with the axis. The body includes a first end22and a longitudinally spaced apart opposite second end24. A through-hole26extends from the first end to the second end and extends along and is surrounded by an annular inner surface28of the body (“annular” meaning extending completely around and being spaced from an axis to define a passage or hole).

The inner surface28defines a first portion30of the through-hole26extending axially from the second end24, a second portion32extending axially from the first portion towards the first end22, and a third portion34extending axially from the second portion to the first end22.

A first portion of the inner surface28facing and defining the through-hole first portion30is a radiused surface36whereby the diameter of the through-hole26increases extending through the first portion30towards the second end24. A second portion of the inner surface28facing and defining the through-hole second portion32has a narrowed throat is a constant diameter surface38whereby the through-hole26has a constant diameter throughout the second portion. A third portion of the inner surface28facing and defining the through-hole third portion34is a frustum-shaped surface40whereby the diameter of the through-hole26decreases extending through the third portion from the first end22.

A protrusion42extends radially from the inner surface28into the through-hole26, and extends longitudinally along the entire inner surface third portion40from the first end22to the inner surface second portion38. The protrusion extends circumferentially along the inner surface third portion essentially the thickness of the protrusion and extends radially to an outer surface44that has the same radius as the inner surface second portion38. The protrusion blends into the inner surface second portion38, that is, there is no radial discontinuity of the inner surface28where the protrusion intersects the second inner surface second portion.

The hoop body18includes a radially enlarged collar46at the body second end24. The collar extends longitudinally from the second end to about even with the start of the inner surface third portion40. The tether16is attached to a collar portion48that is radially aligned with the hoop protrusion42, that is, a plane extending from the axis20through the protrusion would intersect the collar portion48.

The hoop14further includes an external rib52(see alsoFIG. 3) extending away from the body18and attached to the collar portion48. The rib is generally triangle-shaped and includes a first side radially aligned with the protrusion40and extending radially along the collar portion, a second side extending longitudinally along the outside of the body18from the collar portion to the body first end22, and a third side52extending from the body first end22to the collar portion48. The thickness of the rib is about equal to the thickness of the protrusion40.

FIGS. 11 and 11Ais a more detailed view illustrating the hoop14being attached to the air valve V shown inFIG. 5, the hoop being at its installed position. The air valve is a Presta type air valve, Presta and Schrader type air valves being the most common air valve types used in bicycling. The illustrated air valve includes an externally threaded valve stem S and a reduced diameter valve assembly A disposed at the free end of the air valve. The valve stem has a standard 6V1 external thread; a table of standard bicycle air valve thread types per ISO 4570 is listed in Table 1:

As illustrated inFIG. 11, the hoop14is attached to the valve stem S with the end22of the hoop facing towards the free end of the valve stem V.

The radiused inner surface first portion36enables the hoop14to slide onto and over the valve stem external threads without hanging up regardless of manufacturing variations in the threads. The lack of radial discontinuity at the transition of the inner surface second portion38to the hoop protrusion42enables the protrusion to slide onto the valve stem external threads without hanging up against the valve stem.

The constant diameter inner surface second portion38is sized to form an interference fit with the valve stem S that reliably retains the hoop14on the valve stem at its installed position. The radial interference fit between the inner surface second portion and the valve stem is 0.25 millimeters (about one-hundredth of an inch). Radial expansion of the inner surface second portion38is resisted by the combined radial thicknesses of the hoop body18and the collar46to maximize the elastic force applied by the inner surface second portion against the valve stem. And as best shown inFIG. 11A, the constant diameter inner surface second portion48has a longitudinal length of about 1.412 millimeters (about 0.0556 inches) that is about equal to twice the thread pitch to assure the full interference fit is generated by the threads and is not effectively reduced by interactions with the thread valleys.

In other possible embodiments the inner surface second portion48may extend a longitudinal length about equal to three times the thread pitch (for example, 3.87 millimeters (about 0.152 inches) if attached to an 11V1 thread type).

The valve stem S also extends through the inner surface third portion40whereby the hoop protrusion28also forms an interference fit with the valve stem. Radial deflection of the hoop protrusion is resisted by the inner surface third portion40as well as the stiffening rib50so as to apply increased elastic force by the protrusion42as compared to that applied if the rib were absent.

The longitudinal length of the hoop protrusion42is about 1.5 times the thread pitch to assure the full interference fit is generated between the threads and the protrusion and is not effectively reduced by interactions with the thread valleys. The hoop protrusion stiffens the side of the hoop14and applies a force to the facing side of the valve stem S.

Furthermore, the combined longitudinal length of contact of the hoop protrusion42and the inner surface second portion38along the valve stem S assists in resisting rotational displacement of the hoop relative to the valve stem that might lessen resistance to the hoop sliding off the valve stem. Forces applied to the hoop urging relative rotation of the hoop relative to the valve stem can be generated by tension applied by the tether16to the hoop14or applied to the hoop by the user pulling on the cap12while removing the cap from the air valve V.

FIGS. 12 and 13illustrate the cap12. The cap is hollow and extends from an open end54to a closed end56. The cap includes an elongate tubular member58disposed at the open end of the cap and closed by an end wall60at the closed end of the cap. The tubular member extends along and is axisymmetric with an axis62. The cap axis defines a radial direction perpendicular to the axis, a longitudinal direction parallel with the axis, and a circumferential direction about the axis. The tubular member includes an annular inner surface64that surrounds and defines a through-hole66extending along the axis.

The through-hole66is configured to receive the end of the Presta air valve V shown inFIG. 11. The inner surface64includes a uniform diameter inner surface first portion68that surrounds and defines a uniform diameter through-hole portion70.

The cap12further includes a first pair of protrusions that include a first protrusion72and second protrusion74, and a second pair of protrusions that include a third protrusion76and a fourth protrusion78. As seen inFIG. 12, each protrusion has a rounded cross-section, extends a circumferential distance along the inner surface first portion68, and extends radially into the through-hole66from the inner surface first portion68. Each protrusion is also longitudinally elongate and extends longitudinally along substantially the length of the inner surface portion68for a distance substantially greater than the circumferential distance the protrusion extends along the inner surface first portion68.

The first pair of protrusions72,74face each other and are angularly spaced 180 degrees apart from one another along the axis62, and the second pair of protrusions76,78also face each other and are angularly spaced 180 degrees apart from one another. The first set of protrusions are angularly spaced 90 degrees apart from the second set of protrusions about the axis62whereby the four protrusions are equally angularly distributed about the axis.

The end wall60is attached to the tubular member and closes the adjacent end of the tubular member58. The end wall60extends radially outwardly from the tubular member to define an exposed circular rim80(see alsoFIG. 1). The tether16is attached to a portion of the rim.

Referring back toFIGS. 1 and 3, the tether16is shown in those figures in an unstressed or unstretched state. The tether includes a molded-in intermediate arched or curved portion82that holds the cap12and the hoop14closer together when the valve cap assembly is unstressed as compared to when the arch is forced to extend along a straight line as can be seen comparingFIG. 5andFIG. 6. In the illustrated embodiment the arch is formed to normally follow a substantially semi-circular path.

As shown inFIG. 6, the tether16can be elastically stretched to “flatten” the arch82and enable tether to extend substantially its fully developed linear length when placing the cap12on the end of the air valve V. After the cap is placed on the end of the air valve, the elasticity of the tether enables the tether to “unflatten”, restoring the arch in the tether as shown inFIG. 7. There is sufficient remaining tension in the tether as shown inFIG. 7whereby the arch urges the cap and the hoop14towards each other to assist in maintaining the tight clearance between the cap and hoop as shown inFIG. 7.

FIG. 14is a sectional view ofFIG. 7illustrating the cap12over the end of the air valve V. The end of the air valve is received in the cap through-hole66. The cap annular inner surface64surrounds the end of the air valve and the uniform diameter inner surface portion68has sufficient longitudinal length to cover about seven times the thread pitch (or about 5.6 millimeters [about 0.22 inches]).

Each of the first pair of cap protrusions72,74extend radially into the cap through-hole66a distance to generate at least a 0.25 millimeter interference fit between the cap and the air valve stem S.

In the illustrated cap the interference fit generated by the first pair of protrusions is sufficient to retain the cap on the air valve while riding the bicycle. Each of the second pair of cap protrusions76,78extend radially into the cap through-hole66a lesser distance than the first pair of cap protrusions to generate a smaller interference fit with the valve stem to maintain alignment and resist cocking of the cap while on the air valve V. In other possible cap embodiments, the cap protrusions may extend radially into the cap through-hole the same distances.

As shown inFIG. 14, the tether16is connected to the cap12and the hoop14so that when the cap is covering the air valve V the tether extends axially along one side of the air valve, and the tether is aligned radially with the first pair of cap protrusions72,74. This enables a user to squeeze the cap for removing the cap along the sides of the cap radially aligned with the second pair of cap protrusions76,78without obstruction from the tether. The user can squeeze the cap with opposing fingers and can press up against the cap rim80to assist in sliding the cap off the air valve.

Because the cap protrusions72-74are longitudinally elongate members, they essentially slide along the tops of the external threads of the air valve V without being caught between the thread valleys. This enables the cap to be placed on and off the air valve V without catching the external threads and therefore without having to yank the cap off the air valve to overcome catching of the cap protrusions with the external threads.

The cap protrusions72-74being longitudinally elongate and circumferentially spaced apart from one another enable air flow between the protrusions along the air valve V that prevents a vacuum or suction being generated that can resist a user attempting to place the cap on the air valve V or attempting to remove the cap from the air valve.

Presta-type air valves may have a uniform-diameter stem having an externally threaded stem portion adjacent the valve A and a smooth, unthreaded stem portion extending from the threaded stem portion to the tire. With such valves, the hoop can be located along the unthreaded stem portion when in its installed position, and the cap, when on the end of the air valve, can extend from the end of the air valve, past the threaded stem portion, and to the unthreaded stem portion. The cap protrusions can extend longitudinally far enough and be sized to form interference fits with both the externally threaded portion of the valve and the unthreaded portion of the valve. Each cap protrusion may extend a constant radial distance along its entire longitudinal length, or the radial distance may differ for the cap portion that will face the threaded portion of the valve as compared to that for the cap portion that will face the unthreaded portion of the valve when the cap is covering the end of the valve.

FIG. 15illustrates a second embodiment valve cap assembly110attached to and covering an end of a Schrader type air valve Vs. The construction of the cap, hoop, and tether of the valve cap assembly110is similar to that of the first embodiment valve cap assembly but the cap and hoop are modified to fit over and form interference fits with both the threaded valve stem portion St and the unthreaded valve stem Ss of the air valve Vs. In this embodiment the cap protrusions define a 0.32 millimeter (about 0.013 inch) radial interference fit between the cap protrusions and the valve stem when the cap is covering the end of the air valve.

While this disclosure includes one or more illustrative embodiments described in detail, it is understood that the one or more embodiments are each capable of modification and that the scope of this disclosure is not limited to the precise details set forth herein but include such modifications that would be obvious to a person of ordinary skill in the relevant art including (but not limited to) changes in material selection, size, interference fit and length of interference fit, number, arrangement, and cross-sectional profile of the cap protrusions or hoop protrusions (including but not limited to, circular, concave, convex, trapezoidal, and rectangular cross-sections), the length, shape, and flexibility of the tether, as well as such changes and alterations that fall within the purview of the following claims.