Abstract:
The present application discloses a tire and wheel combination for a vehicle comprising a wheel comprising a rim; a tire comprising an annular side wall, an interior surface, wherein the tire is mounted on the rim; and a foam support insert comprising a compressible annular main body, wherein the annular main body comprises a central bore configured to received the wheel rim, and having an outer diameter that is greater than the inner diameter of the interior surface of the tire and being compressed and mounted inside the air cavity of the tire and circumferentially secured to the interior surface of the tire, wherein the foam support insert further comprises a first foam insert having a different foam density than the annular main body, and the foam insert is coupled to the main body and configured with regular or irregular geometric design; wherein the tire and wheel combination is not air tight sealed and filled with pressurized air, and vehicle comprising such combination.

Description:
RELATED APPLICATION 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/154,937 filed Feb. 24, 2009, which is incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The present disclosure relates generally to the field of inserts for vehicle tires, such as model vehicle tires and radio controlled (RC) model vehicle tires. More specifically, the disclosure relates to a foam insert for an RC vehicle. Such RC vehicles may be used for rock crawling. 
         [0003]    Some RC vehicles are designed for rock crawling, requiring navigation over obstacles and extremely uneven, rocky surfaces. RC vehicles typically include an insert to maintain the shape of the tire instead of air pressure, as is generally used for larger vehicles. Because proper traction and tire behavior is so important to overcoming these obstacles, it is desirable to provide tire inserts for such an RC vehicle that allow the tire to be flexible enough to conform to the shape of the terrain to provide adequate traction while still being firm enough to provide enough support for the tires. 
         [0004]    It would be desirable to provide an improved foam insert for RC model vehicles. 
       SUMMARY OF THE INVENTION 
       [0005]    One embodiment of the application relates to a tire and wheel combination for a vehicle comprising a wheel comprising a rim; a tire comprising an annular side wall, an interior surface, wherein the tire is mounted on the rim; and a foam support insert comprising a compressible annular main body, wherein the annular main body comprises a central bore configured to received the wheel rim, and having an outer diameter that is greater than the inner diameter of the interior surface of the tire and being compressed and mounted inside the air cavity of the tire and circumferentially secured to the interior surface of the tire, wherein the foam support insert further comprises a first foam insert having a different foam density than the annular main body, and the foam insert is coupled to the main body and configured with regular or irregular geometric design; wherein the tire and wheel combination is not air tight sealed and filled with pressurized air. In one aspect of the tire and wheel combination, the main body of the foam support insert comprises two or more layers of foam of different density. In one variation, the two or more layers of foam are concentric layers or coaxially arranged layers. In another variation, the two or more layers of foam are of the same width (or thickness) or of different width (or thickness). In another aspect of the tire and wheel combination, the main body comprises an inner layer of foam coupled together and sandwiched between at least two outer layers of foam, wherein the inner layer of foam has a different foam density than the outer layers of foam. In another aspect, the outer layers of foam have lower foam density than the inner layer of foam, or wherein the outer layers of foam have higher foam density than the inner layer of foam. In one variation of the above, the outer layers of foam comprise of a visco-elastic polyurethane foam, and the inner layer of foam comprises of conventional urethane foam. In another aspect of the combination, the main body comprises a plurality of openings arranged symmetrically or asymmetrically and coaxially with the foam support insert, and the openings configured to receive the first foam insert comprising a first set of multiple elongated foam inserts having higher density and stiffness than the main body. In another variation, the elongated foam inserts have generally oval, square or triangular cross-section profile. In another aspect, the above combination further comprises a second set of foam inserts on the outer periphery of the main body of the foam support insert, wherein the second set of foam inserts comprise of the same or different foam density than the first set of foam inserts. 
         [0006]    In each of the above aspects and variations, the foam inserts comprise of a coaxial single integral body comprising multiple regular or irregular geometric protrusions, wherein the single integral body is coupled to the main body and forms the inner bore of the main body of the foam support insert. In a particular variation, the main body and the foam insert form two concentric shaped doughnut forms, with the main body forming an inner coaxial body and the support insert forming an outer coaxial body. In a particular variation, the single integral body comprises of a higher density foam than the foam of the main body. In another variation, the geometric protrusion(s) of the single integral body is a regular star shaped having at least two protrusions, or two star-shaped arms. In another variation, the geometric protrusions of the single integral body is a regular star shaped having at three, four, five, six, seven or at least eight protrusions. In a particular variation of each of the above, the foam density of the main body and the density of the foam insert is about 1.70 to about 15 lbs/cu. ft, and wherein the foam indentation force deflection (IFD) of the main body is about 6 to about 30 and the foam indentation force deflection (IFD) of the foam insert is about 18 to 45 and up. In a particular variation, the main body has a foam density of about 1.5 to 2.5 lbs/cu. ft and the IFD of about 6 to 24, and the foam insert has a foam density greater than about 2.5 to about 15 lbs/cu. ft. In a variation of each of the above, the main body and the foam inserts are made from open-cell foam, closed-cell foam, urethane foam, visco-elastic polyurethane foam, polymethacrylimide foam, polyvinylchloride foam, polypropylene foam, polyethylene foam, urethane foam, latex foam and combinations thereof. In another variation of each of the above, the wheel is formed from a rigid material selected from aluminum, brass, steel and hard plastics and combinations thereof. 
         [0007]    In another embodiment, there is provided a foam support insert for inserting in a tire and wheel combination of a vehicle, wherein the foam support insert comprising a compressible annular main body, wherein the annular main body comprises a central bore configured to received the wheel rim, and having an outer diameter that is greater than the inner diameter of the interior surface of the tire and being compressed and mounted inside the air cavity of the tire and circumferentially secured to the interior surface of the tire, wherein the foam support insert further comprises a first foam insert having a different foam density than the annular main body, and the foam insert is coupled to the main body and configured with regular or irregular geometric design. In one variation of the above, the main body comprises a plurality of openings arranged symmetrically or asymmetrically and coaxially with the foam support insert, and the openings configured to receive the first foam insert comprising a first set of multiple elongated foam inserts having higher density and stiffness than the main body. In one aspect of the above, the elongated foam inserts have generally oval, square or triangular cross-section profile. In another aspect of the above, the foam support insert further comprises a second set of foam inserts on the outer periphery of the main body of the foam support insert, wherein the second set of foam inserts comprise of the same or different foam density than the first set of foam inserts. In a variation of each of the above, the foam inserts comprise of a coaxial single integral body comprising multiple regular or irregular geometric protrusions, wherein the single integral body is coupled to the main body and forms the inner bore of the main body of the foam support insert. In one variation of the above, the single integral body comprises of a higher density foam than the foam of the main body. In a particular variation, the geometric protrusion(s) of the single integral body is a regular star shaped having at least four protrusions. In another variation of the above, the foam density of the main body and the density of the foam inserts are about 1.70 to about 15 lbs/cu. ft. In another variation, the foam density of the main body is about 1.5 to 2.5 lbs/cu. ft, and the foam density of the foam insert is greater than about 2.5 to about 15 lbs/cu. ft. 
         [0008]    In another embodiment, there is provided a method for maintaining the traction of a vehicle while driving of the vehicle in rough terrain, the method comprising equipping the vehicle with a tire and wheel combination comprising: a wheel comprising a rim; a tire comprising an annular side wall, an interior surface, wherein the tire is mounted on the rim; and a foam support insert comprising a compressible annular main body, wherein the annular main body comprises a central bore configured to received the wheel rim, and having an outer diameter that is greater than the inner diameter of the interior surface of the tire and being compressed and mounted inside the air cavity of the tire and circumferentially secured to the interior surface of the tire, wherein the foam support insert further comprises a first foam insert having a different foam density than the annular main body, and the foam insert is coupled to the main body and configured with regular or irregular geometric design; wherein the tire and wheel combination is not air tight sealed and filled with pressurized air. In one variation of the method, the vehicle is an RC vehicle. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    These and other features, aspects, and advantages of the present invention will become apparent from the following description, appended claims, and the accompanying exemplary embodiments shown in the drawings, which are briefly described below. 
           [0010]      FIG. 1  is an isometric view of a radio-controlled vehicle including tires with a foam insert according to an exemplary embodiment. 
           [0011]      FIG. 2  is an exploded view of a tire assembly including a foam insert according to an exemplary embodiment. 
           [0012]      FIG. 3  is a front view of a foam insert for a tire according to an exemplary embodiment. 
           [0013]      FIG. 4  is an exploded view of the foam insert of  FIG. 3 . 
           [0014]      FIG. 5  is an isometric view of a foam insert for a tire including a second set of inserts according to another exemplary embodiment. 
           [0015]      FIG. 6  is a partially exploded view of the foam insert of  FIG. 5 . 
           [0016]      FIG. 7  is an isometric view of a foam insert for a tire including a second set of inserts according to another exemplary embodiment. 
           [0017]      FIG. 8  is a partially exploded view of the foam insert of  FIG. 7 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0018]    The invention is described in more detail hereinafter with reference to exemplary embodiments. In the figures, for the sake of clarity, the same reference numerals are used for similar components in different embodiments. 
         [0019]    Referring to  FIG. 1 , a radio controlled model vehicle  10  is shown according to an exemplary embodiment. The vehicle  10  is configured to be controlled via radio waves from a handheld controller. The vehicle  10  preferably comprises a substantially chassis or frame  12 . An aerodynamically shaped shell or body  13 . The body  13  may include a multitude of vehicular detailing. The detailing may be three dimensional merely surface ornamentation or indicia. Such detailing may be functional or may simply simulate similar functional elements on larger vehicles. 
         [0020]    The frame  12  is coupled to a multitude of wheels  20  (generally four) with a suspension  14 . According to a one embodiment, each of the wheels  20  has a suspension  14 . One or more motors  16  provide power to the vehicle  10  and turn the wheels  20 . Each wheel  20  or pair of wheels  20  (e.g., the pair of front wheels and the pair of rear wheels) may also be coupled to a steering assembly  18 . By providing the wheels  20  for the vehicle  10  with a suspension  14  and or steering assembly  18 , the vehicle  10  is better able to maneuver the wheels  20  and traverse over relatively rough terrain. 
         [0021]    Referring now to  FIG. 2 , a wheel  20  for an RC vehicle  10  is shown according to an exemplary embodiment. The wheel  20  comprises a rim  22  that receives a tire  24 . The rim  22  is formed from a relatively rigid material such as a metal (e.g., aluminum, brass, steel, etc.) or a polymer (e.g., nylon). The wheel  20  is coupled to the axle that is driven by the motor  16 . The tire  24  is formed from a resilient material such as rubber and is coupled to the rim  22 . According to various exemplary embodiments, the tire  24  may be affixed to the rim  22  with an adhesive, with a mechanical connection (e.g., by being trapped between two portions of the rim), or any other suitable fastening method known in the art. 
         [0022]    The tire  24  includes annular side walls  26  that are coupled to the rim  22  and a tread portion  28  that extends around the periphery of the tire  24  and contacts the surface upon which the vehicle  10  is driven. The tire  24  is configured to flex and deform so that the tread  28  can better conform to the surface upon which the vehicle  10  is driven. However, unlike tires on larger vehicles, the tires  24  on most RC model vehicles  10  are not filled with pressurized air. Instead, a foam support insert  30  is provided within the tire  24 , between the tire  24  and the rim  22 . The foam support insert  30  is a compressible body that allows the tire to deform  24  but prevents excessive deformation such as “bottoming out” such that the rim  22  may come within close proximity of contacting the driving surface. According to one embodiment, the foam support insert  30  is formed from a closed-cell foam such as a urethane foam. While the circumferential wall is referred to in this disclosure as the tread or tread portion  28 , it should be understood that the raised tread pattern of the vehicle wheel  20  may extend around the surface of the wheel onto the sidewalls  26  as well. 
         [0023]    Referring now to  FIGS. 3-4 , a foam support insert  30  is shown according to an exemplary embodiment. The foam support insert  30  includes a main body  32  and one or more elongated inserts  40 . The main body  32  is an annular body (e.g., donut-shaped, ring-shaped, etc.) that includes a central bore  34  that is configured to receive the wheel rim  22 . The foam support insert  30  may have an outer diameter that is less than the diameter of the tread portion  28  of the tire  24  such that there is a gap between the foam support insert  30  and the tread portion  28 . According to another exemplary embodiment, the foam support insert  30  may have an outer diameter that is equal to or even greater than the diameter of the tread portion  28  of the tire  24 . As such, the foam support insert  30  may be compressed when it is inserted between the rim  22  and the tire  24 . Compressing the foam support insert  30  within the tire  24  induces a pre-load such that the foam exerts a constant force outward on the tire  24 . 
         [0024]    The main body  32  may comprise two or more layers or laminae. As shown in  FIGS. 3-8 , in a preferred embodiment, the main body  32  comprises two outer layers  36  and an inner layer  38 . The outer layers  36  and the inner layer  38  may be approximately the same thickness or may have different thicknesses. The outer layers  36  may have a different stiffness and different density than the inner layer  38  or the outer layers  36  may have different stiffness and different density compared to each other. For example, the outer layers  36  may be formed from a relatively stiff foam to support the sides of the tread portion  28  and the side walls  26 , while the inner layer  38  may be formed from a relatively soft foam. In a preferred embodiment, the outer layers  36  are formed of a visco-elastic polyurethane foam, commonly known as a “memory foam”, while the inner layer  38  is formed from a stiffer conventional urethane foam. Memory foam allows the tire  24  to flex more over obstacles and rough terrain does not expand back to its original shape as quickly as conventional urethane foam. This reduces the likelihood that the vehicle  10  will bounce or hop when crossing rough terrain. 
         [0025]    According to various exemplary embodiments, the layers  36  and  38  may be coupled together with a wide variety of suitable fastening methods such as adhesives, hook and loop fasteners, or mechanical fasteners, or the like. While  FIGS. 3-8  illustrate a foam support insert having a main body with only three layers, it should be understood that, according to other exemplary embodiments, the foam support may have more or fewer layers. For example, the main body may have 2, 3, 4, 5, 6 or more layers of foam, wherein the different layers of foam may have the same or different foam density. 
         [0026]    A plurality of through openings  42  (e.g., holes, apertures, cavities, etc.) are provided in the main body  32  that are configured to receive corresponding inserts  40 . The inserts  40  extend laterally, through the layers  36  and  38  and allow a user to selectively alter the compression behavior of the foam support insert  30  (e.g., to allow the vehicle  10  to traverse various terrains). According to a preferred embodiment, the inserts  40  are relatively dense and stiff compared to the main body  32 . The inserts  40  create localized areas of stiffness in the foam support insert  30 . Therefore, when the vehicle is traversing a rough or uneven surface, such as when the tire is in contact with a rock or a boulder, for example, the portions of the tread portion  28  of the tire  24  radially aligned with the inserts  40  do not compress toward the rim  22  as much as the intermediate portions. The uneven compression distorts the tread portion  28  and helps the tire  24  better grip the driving surface and propel the vehicle  10 , maintaining traction and allowing the vehicle to continue traversing over the terrain. 
         [0027]    By combining a relatively stiff insert  40  with a relatively soft main body  32 , advantages from both types of foam are realized. The inserts  40  provide a support for the tire  24  in both a radial direction (e.g., from the rim  22  out to the tread portion  28 ) and in an axial direction (e.g., by pushing against the side walls  26 ). The soft main body  32  on the other hand absorbs shock and reduces the effect of any “bounce” from the stiff inserts  40 . 
         [0028]    As shown in  FIGS. 3-4 , according to one exemplary embodiment, the inserts  40  have a generally triangular cross-section profile. The inserts  40  are arranged symmetrically about the inner bore  34  of the main body  32 , oriented to form outwardly-facing wedges. The wedge shape of the triangular inserts  40  effectively resists compression from a radial force directed inward (e.g., from the driving surface due to the weight of the vehicle  10 ). 
         [0029]    According to one exemplary embodiment, the openings  42  in the main body  32  are formed with a die-cutting operation. The original material occupying the openings (e.g., the removed portions of the outer layers  36  and inner layer  38 ) may not be disposed of and may instead be provided to the user along with the inserts  40 . In this way, the user may customize the foam support insert  30  by inserting into the openings  42  the original material, the inserts  40  or even nothing at all. For instance, a user may only use inserts  40  in some of the openings  42  while using the original material  42  in other openings  42 . 
         [0030]    While the foam support insert  30  of  FIGS. 3-4  is shown comprising six equally spaced triangular inserts  40  and corresponding openings  42 , it should be understood that a number of variations are possible. For instance, as shown in  FIGS. 5-8 , the inserts  40  and openings  42  may be generally pill-shaped. A greater or fewer number of inserts  40  and openings  42  may be provided. For instance, the foam support insert  30  may include eight inserts  40  and openings  42  as shown in  FIGS. 5-8 . According to still other exemplary embodiments, the inserts may not be equally spaced and may instead be provided in groups spaced around the main body  32 . The openings  42  may be located such that they are surrounded by the main body  32 , may extend inward from the outer periphery of the main body (as shown in regards to openings  46  in  FIG. 6 ), or may extend outward from the inner bore  34 . 
         [0031]    Referring now especially to  FIGS. 5-6 , according to still other exemplary embodiments, a foam support insert  30  may include a first set of inserts  40  and openings  42 , and a second group of inserts  44  that are received in a second group of openings  46 . The second inserts  44  may be formed of the same material as the first inserts  44  or may be a different material. 
         [0032]    According to a preferred embodiment, the second inserts  44  have a generally pentagonal cross-section profile. The second inserts  44  are received in corresponding openings  46  (e.g., grooves, hollows, cut-outs, etc.) provided about the periphery of the main body  32 . The second inserts  44  are generally offset from the first inserts  40 . By placing the second inserts  46  closer to the periphery of the main body  32  and, therefore, closer to the tread portion  28  of the tire  24 . The second inserts  46  then effect the deformation of the tire  24  differently than the first inserts  40  as the vehicle  10  traverses the uneven terrain. 
         [0033]    Referring now to  FIGS. 7-8 , according to still another exemplary embodiment, a foam support insert  30  may include a first set of inserts  40  and openings  42  similar to those shown in  FIGS. 5-6 , and a second set of openings  48 . The second openings  48  are similar to the openings  46  shown in  FIGS. 5-6 , but do not extend through all the layers of the main body  32 . Instead, the openings  48  are provided only in the middle layer  38 . According to other exemplary embodiments, openings may be provided in only the outer layers  36  and not the middle layer  34 . Such an incomplete opening  48  may receive a similarly shortened insert or may be left open, as shown in  FIGS. 7-8 . 
         [0034]    Similarly, the openings  42  for the inserts  40  may only extend part of the way through the main body  32 . For instance, openings  42  may only extend through one of the outer layers  36  and the middle layer  38  and not through the opposite outer layer  36 . The inserts  40  received in the shortened openings  42  would likewise be shorter than the overall depth of the main body  32 . Such a shortened insert  40  may be desirable, for example, to encourage a different deformation near the outside sidewall  26  of the tire  24  or the inside sidewall  26 . 
         [0035]    Referring now to  FIGS. 9-10 , according to yet another exemplary embodiment, the inserts  40  may be formed as a single integral body, joined together by a ring  41 . In a preferred embodiment, the ring  41  forms the inner bore  34  as shown in  FIGS. 9 and 10  and receives the rim  22 . 
         [0036]    By forming the inserts  40  as a single body, the assembly of the foam support insert  30  is made easier. Instead of fitting multiple inserts  40  into multiple openings  42 , the single body can be easily nested within the main body  32 . Further, the ring  41  helps to support the inserts  40  and reduces the likelihood that they will flex or twist relative to the main body  32 . Still further, the ring  41  supports the inserts  40  such that can better resist a radial force (e.g., compression from the tire  24 ), therefore creating a larger difference between the stiffness of the areas of the foam support insert  30  proximate to the inserts  40  and the stiffness of the main body  32  between the inserts  40 . 
         [0037]    According to other exemplary embodiments, an additional laminate piece, similar to main body  32 , or an additional solid foam piece may form another concentric body within the ring  41  to form the bore  34 . The ring  41  may also be formed on the outside edge of the inserts  40  and lie proximate to the inside surface of the tread portion  28  of the tire  24 . 
         [0038]    As used herein, the terms “approximately,” “about,” “substantially”, and similar terms are intended to have a broad meaning in harmony with the common and accepted usage by those of ordinary skill in the art to which the subject matter of this disclosure pertains. It should be understood by those of skill in the art who review this disclosure that these terms are intended to allow a description of certain features described and claimed without restricting the scope of these features to the precise numerical ranges provided. Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or alterations of the subject matter described and claimed are considered to be within the scope of the invention as recited in the appended claims. 
         [0039]    It should be noted that the term “exemplary” as used herein to describe various embodiments is intended to indicate that such embodiments are possible examples, representations, and/or illustrations of possible embodiments (and such term is not intended to connote that such embodiments are necessarily extraordinary or superlative examples). 
         [0040]    The terms “coupled,” “connected,” and the like as used herein mean the joining of two members directly or indirectly to one another. Such joining may be stationary (e.g., permanent) or moveable (e.g., removable or releasable). Such joining may be achieved with the two members or the two members and any additional intermediate members being integrally formed as a single unitary body with one another or with the two members or the two members and any additional intermediate members being attached to one another. 
         [0041]    The term “foam support insert” is used herein to refers to the insert having a main body  30  that may be inserted and mounted inside the air cavity of a tire. The term “insert” or “foam insert” refers to the insert such as the foam inserts  40  that comprises a part of the “foam support insert” and may be inserted into the main body of “foam support insert.” The “insert” or “foam insert” has a different foam density than the “foam support insert.” In a preferred aspect, the foam insert has a higher density than the foam support insert and is more resilient and stiffer than the foam support insert. 
         [0042]    The term “indentation for deflection” or “IFD” is defined according to the Joint Industry Standards and Guidelines for foams as the amount of force, in pounds, required to indent a fifty square inch, round indentor foot into a predefined foam specimen a certain percentage of the specimen&#39;s total thickness. The IFD measures the firmness of the foam based on a physical property, the IFD. Typically, the IFD at 25% deflection use (pounds/50 insq. on 20″×20″×4″) ranges about 6 to about 45 and higher. 
         [0043]    References herein to the positions of elements (e.g., “top,” “bottom,” “above,” “below,” etc.) are merely used to describe the orientation of various elements in the accompanying drawings. It should be noted that the orientation of various elements may differ according to other exemplary embodiments, and that such variations are intended to be encompassed by the present disclosure. 
         [0044]    It is important to note that the construction and arrangement of the foam inserts as shown in the various exemplary embodiments is illustrative only. Although only a few embodiments have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter described herein. For example, elements shown as integrally formed may be constructed of multiple parts or elements, the position of elements may be reversed or otherwise varied, and the nature or number of discrete elements or positions may be altered or varied. The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. Other substitutions, modifications, changes and omissions may also be made in the design, operating conditions and arrangement of the various exemplary embodiments without departing from the scope of the present invention.