Abstract:
A single piece valve extension support for vehicles with dualled tires and wheels using inflation valve extensions on the inner wheel. The valve extension support, made from a compressible elastomeric foam material, has an orifice through which the valve extension can pass. The valve extension support is inserted in the vent hole of the outer wheel, compressing the foam elastomeric material and generating an interference fit with the vent hole. The valve extension support is compressed around the valve extension passing through its&#39; orifice. In this way, the valve extension support is able to dampen vibration that can lead to fatigue cracks in the inflation valve assembly, causing loss of air pressure in the inner dual tire and wheel assembly. Retention flanges on either side of the wheel prevent accidental removal of the valve extension support.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to dual wheel structures on vehicles, such as those found on tractor-trailers, and more particularly to a valve extension support for use in dual wheel applications that dampens vibration of a valve extension attached to the inflation valve of the inner dual wheel. 
     In wheel applications where wheels are dualled on an axle, it is often necessary to increase the length of the inflation valve associated with the inner wheel so that it can be more easily accessed from the outside of the vehicle to allow for proper monitoring and adjustment of the inner tire&#39;s air pressure. The most common method for lengthening the inflation valve is to use an inflation valve extension. Typically, the inflation valve extension takes the form of a small diameter metal tubular device that attaches to the end of the inflation valve of the inner wheel and extends outward through a vent hole in the outer wheel. 
     Unfortunately, the weight of the inflation valve extension, coupled with the high rotational speeds of wheels in service, increases the vibration magnitude and stress on the inner wheel&#39;s inflation valve during service. This leads to fatigue cracks in the inflation valve, often resulting in a loss of tire pressure that may in turn lead to tire damage and/or poor fuel economy. 
     Hence, there is a need for a device that can be used to dampen the vibration of an inflation valve fitted with a valve extension installed on an inner dual wheel. Preferably, the device should fit various wheel designs, be easily installed and removed, remain secured after installation, be lightweight, allow access to the end of the inflation valve assembly, and be resistant to a variety of environmental conditions. 
     BRIEF SUMMARY OF INVENTION 
     A valve extension support of the present invention may be used with dualled wheels, where the outer wheel has a vent hole that the valve extension protrudes through. The valve extension support includes a deformable substantially cylindrical main body formed from elastomeric foam material and having inboard and outboard ends. The valve extension support is deformable between three states: an undeformed state, an installed state, and an installation state. The main body has a cross-sectional dimension larger than the vent hole in the undeformed state, but is deformable to be disposed through the vent hole in the installed state. The main body has an associated outboard retention flange at or towards one end, and an associated inboard retention flange at or towards the other end. The outboard flange has a plan view cross-sectional dimension larger than the vent hole in the undeformed and installed states. The inboard retention flange has a cross-sectional dimension larger than the vent hole in the undeformed state and in the installed state, but may be deformed to be smaller than the vent hole in the insertion state. In this manner, the valve extension support may be inserted into the vent hole, and remains deformed while in the vent hole. The main body has a passage passing therethrough that is adapted to grip the valve extension in the installed state due to the deformation of the main body from being “squeezed” in the vent hole. 
     Once installed, the inboard and outboard retention flanges are disposed on opposite sides of the outboard wheel. The two retention flanges are preferably spaced such that the outboard wheel is not laterally squeezed between the flanges, thereby allowing the valve extension support to be easily oriented in a variety of positions relative to the vent hole. The two retention flanges may be substantially identical, or may be different. There may be an optional valve end recess on one or both sides of the valve extension support to provide clearance for monitoring air pressure. 
     With the retention flanges on both ends of the valve extension support, the valve extension support device is safely retained in the vent hole, such that vibration and motion of the wheel in normal operation should not cause the valve extension support to become dislodged from the outboard wheel. The interference compression fit of the valve extension support device in the vent hole also prevents it from becoming dislodged is service. 
     The valve extension support device can be removed by pushing or pulling it out of the vent hole. Sufficient force must be exerted to overcome the interference fit and collapse the appropriate retention flange. 
     The valve extension support should be made from a low density elastomeric foam material, preferably of a heat resistant closed cell type with ultraviolet light and ozone inhibitors. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows a dualled wheel assembly with a valve extension support according to the present invention. 
     FIG. 2 shows one embodiment of the valve extension support according to the present invention. 
     FIG. 3 shows another embodiment of the valve extension support according to the present invention. 
     FIG. 4 shows a plan view of the valve extension support of FIG. 2, but with a slot type orifice. 
     FIG. 5 shows a sectional view through section line A—A of FIG.  4 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to FIG. 1, an inner dual wheel  10  and inner dual tire  12  are shown mounted on a vehicle, over the axle end components such as the brake drum  30 , hub  32 , and wheel studs  34 . Also shown is the corresponding outer dual wheel  20  and outer dual tire  28 , mounted such that one of the vent holes  22  of the outer wheel  20  aligns with the inflation valve  14  of the inner wheel  10 . As shown, it is typical for the inflation valve  14  to extend in a general axial direction toward, and possibly through, a vent hole  16  in the inner wheel  10 . An inflation valve extension  40  is attached to the end of the inflation valve  14 , in a manner well known in the art. The inflation valve extension  40  passes through the corresponding vent hole  22  in the outer wheel  20 , so as to allow for proper monitoring and adjustment of the air pressure of the inner tire  12 . 
     The valve extension support  50  of the present invention is inserted into the vent hole  22  of the outer wheel  20 , and generally surrounds the valve extension  40  in that area. It is intended that the valve extension support  50  grip the valve extension  40  in the area proximate the vent hole  22  of the outer wheel  20 , thereby minimizing the motion of the valve extension  40  relative the inner and outer wheels  10 , 20 . 
     The valve extension support  50  includes a generally cylindrical main body  60 , an orifice  52  forming a passage through the main body  60 , a inner retention flange  70 , and an outer retention flange  80 . The retention flange  70  is disposed proximate one end of the main body  60 . The retention flange  70  should be larger in cross section than the vent hole  22  in at least one direction when viewed along the axis of the valve extension support  50 . At the back of the retention flange  70  may be a retention lip surface  74  that cooperates with the backside disc face  24  of the outer wheel  20  so as to prevent the valve extension support  50  from coming out of the wheel vent hole  22  during operation of the vehicle. Behind the retention flange  70  may be a relief groove  76  that allows the retention flange  70  to collapse when pushed into the wheel vent hole  22 . The leading edge  72  of the retention flange  70  should preferably be a chamfered, tapered or radiused to ease installation of the retention flange  70  through the vent hole  22  of the outer wheel  20 . 
     As shown in FIG. 2, the outer retention flange  80  may be substantially identical to the inner retention flange  70 , with a corresponding retention lip surface  84  and groove. Alternatively, as shown in FIG. 3, the outer retention flange may take a different configuration. The purpose of the outer retention flange  80  is to help prevent the valve extension support  50  from being pushed too far through the wheel vent hole  22  during installation or in the installed state. It is intended that the retention lip surface  84  contact the outside disc face  26  of the outer dual wheel  20  when the valve extension support  50  is pushed into the wheel vent hole  22 , thereby preventing over-insertion of the valve extension support  50 . 
     As shown in FIG. 2, the orifice  52  may take the form of a centrally located hole; alternatively, the orifice may take the form of a slit, slot, or the like that allows for passage of the valve extension  40  through the main body  60  of the valve extension support  50 . It is intended that the interior surfaces of the orifice  52  form around the valve extension  40  when the valve extension support  50  is installed in the wheel vent hole  22  of the outer dual wheel  20 , as discussed further below. 
     The valve extension support  50  is made from a compressible elastomeric foam material, such as closed-cell an elastomeric foam material made from polyolefin or other suitable material. The elastomeric foam material has significant spring-back to allow the valve extension support  50  to return to its nominal shape in a variety of environmental conditions. In addition, the elasticity of the material generates the compressive fit that grips the valve extension  40  and aids in retention of the device  50  in the vent hole  22 , as discussed further below. 
     The body  60  of the valve extension support  50  is larger in cross-sectional size than the vent hole  22  in its undeformed state. This size difference provides an interference fit between the valve extension support  50  and the wheel vent hole  22  and compresses the elastomeric material of the valve extension support  50 . The resistance of the main body  60  of valve extension support  50  to this compression helps to keep the valve extension support  50  properly installed through the vent hole  22 . Further, and more directly related to the prime benefit of the present invention, compression of the valve extension support  50  aids in gripping the valve extension tube  40  to dampen vibration. 
     To install the valve extension  40 , the valve extension  40  is passed through the orifice  52  of the valve extension support, and the valve extension support  50  is pressed into the wheel vent hole  22 . More particularly, the leading edge  72  of the valve extension support  50  is directed towards and then through the vent hole  22 . As the leading edge  72  passes through the vent hole  22 , the inner retention flange  70  is temporarily deformed. When the inner retention flange  70  passes the vent hole  22 , ending the insertion state, the inner retention flange  70  should substantially return to its undeformed configuration on inboard side of wheel  20 . However, the main body  60  is now engaged by the vent hole  22 . The difference in cross-sectional size between the main body  60  and the vent hole  22  causes the main body  60  to be compressed, as discussed above. This compression of the valve extension support  50  in the installed state causes compression of the interior surfaces of the orifice  52  against the valve extension  40 . As the valve extension  40  is substantially surrounded radially within the orifice  52 , with the main body  60  of the valve extension support  50  compressed against the valve extension  40  and disposed between the valve extension  40  and the edges of the vent hole  22 , the relative radial motion of the valve extension  40  is quite restricted with respect to the vent hole  22 . This compression-formed radial restriction results in a substantial reduction or dampening of the vibration induced in the valve extension  40 . To complete the installation, the valve extension  40 , with the valve extension support  50  gripped thereto, may then be screwed or otherwise attached to the inflation valve  14 . Alternatively, the valve extension may be connected to the inflation valve  14  first, and then the valve extension support  50  placed around the valve extension  40  and inserted into the vent hole  22  by moving the valve extension support inward along the valve extension  40 . 
     By virtue of its geometry and elastomeric properties, the orifice  52  in the valve extension support  50  does not restrict the orientation of the inflation valve  14  to a specific position relative to the valve extension support  50  or the vent hole  22  of the outer wheel  20 . Therefore, precise alignment of the valve extension  40  is not required. Thus, the valve extension  40  may extend along a line that is not coincident with either the centerline of the vent hole  22 , or the valve extension support  50 . 
     The valve extension support  50  acts to reduce the vibration magnitude of the inflation valve assembly when the wheels are in motion. This vibration dampening results in increased service life of the inflation valve  14  fitted with a valve extension  40 . The valve extension support  50  of the present invention can be installed and removed easily in a number of wheels due to the elastomeric foam material and design geometry. The valve extension support  50  of the present invention is also lightweight and preferably resistant to a variety of environmental conditions. 
     The valve extension support  50  may incorporate an optional valve end recess  56  or pocket to allow for easier access to the inflation valve extension  40 . The recess  56  also helps reduce the weight of the valve extension support  50 . The foam material may be reinforced to prevent tearing in the valve end recess  56  during installation and removal from the outer wheel vent hole  22 . 
     While not required, it is preferred that the distance between the retention lip surfaces  74 , 84  be greater than the section thickness of the wheel disc at the vent hole  22 , leaving a clearance gap between the retention flange  70  and the backside disc face  24 , and possibly another gap between the retention flange  80  and the outside disc face  26 . These clearance gaps allow the valve extension support  50  to be installed into a variety of wheels without regard for the specific disc section thickness of the wheel  20  in the area of the vent hole  22 . In addition, these clearance gaps allow for installation without regard for the relative angles of the vent hole  22 , the valve extension  40 , and the longitudinal axis of the valve extension support  50 . This clearance also provides relief for displaced material when the valve extension support  50  is compressed in the wheel vent hole  22 , minimizing the shrink of the valve end recess  56 , and thus keeping the distal end of the valve extension  40  (relative to the inner tire  12 ) readily accessible. 
     For valve extension supports  50  intended to be installed from one direction, the retention flanges  70 , 80  may be different, with the outer flange  80  being larger than the inner flange, as shown in FIG.  3 . On the other hand, for valve extension supports  50  intended to be installed from either direction, the retention flanges  70 , 80  may be identical, as shown in FIG. 2, thereby facilitating installation in the “reverse” direction. 
     The present invention may, of course, be carried out in other specific ways than those herein set forth without departing from the essential characteristics of the invention. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.