Patent Document

RELATED APPLICATION 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/159,057, filed Mar. 10, 2009, which is incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The present disclosure relates generally to the field of weighted wheel assembly for vehicle, such as wheel assembly for radio controlled (RC) model vehicles. More specifically, the disclosure relates to adjustable and removable weights for wheels for an RC vehicle that may be used for rock crawling. 
         [0003]    Some RC vehicles are designed for rock crawling, requiring navigation over obstacles and extremely uneven, rocky surfaces. Such vehicles are often driven up steep slopes, sometimes approaching a vertical orientation. To maintain stability and reduce the likelihood that the vehicle will tip over, rock crawling vehicles are generally designed with a low center of gravity. RC rock crawling vehicles may have their centers of gravity further lowered by weighting the wheels. Wheels for RC rock crawling vehicles are often weighted with the addition of lead weights, such as lead weights made for balancing tires or lead shot. The weights are usually attached to the outer periphery of the wheel rim, requiring the removal of the tire and any foam tire supports before the weights are added. Further, such weights are often crudely attached to the rim, such as with tape. Using such weights, therefore, represents a time consuming and involved process. Additionally, it is also difficult to change the number or types of weights, requiring the complete removal and re-taping of the weights, along with the removal of the tire. 
         [0004]    It would be desirable to provide an improved adjustable weighted wheel assembly for RC model vehicles. 
       SUMMARY OF THE INVENTION 
       [0005]    One embodiment of the present application relates to a wheel assembly comprising: a wheel comprising a main body, a substantially cylindrical wall, a front hub face and a back hub face comprising a central portion connecting a hub to an outer rim, wherein the front hub face or the back hub face comprise a socket for receiving a removable weight, wherein the socket or the weight is configured with a stop for preventing the weight from dislodging from the socket; a back hub face comprising a back central portion connecting the hub to the back outer rim; and the wheel assembly comprising at least one fastener for securing the weigh in the socket on the main body of the wheel. In one variation of the wheel assembly, the socket or the weight is configured with the stop to prevent the weight from moving in an axial direction toward the back face of the wheel. In another variation, the socket is configured with the stop to prevent the weight from moving in an axial direction toward the front face of the wheel. In one variation as used herein, the fastener may comprise of screws, O-rings, clips, spring loaded clips, brackets, magnets, etc . . . In another variation, the weight may further comprise the “fastener” or may itself be fastened, wherein the weight may be threaded and screwed into the socket having matching threads. In one aspect of the wheel assembly, the socket comprises of at least one, two, three, four, five or six sockets for receiving a plurality of weights, and wherein the weights are secured in the sockets with at least one fastener. In another variation, the wheel assembly comprises seven, eight, nine, ten or more sockets. In a particular embodiment, the socket is a concentric socket adapted to retain a weight. The weight may comprise of one or more weights that may be inserted in the socket, and the weight may be configured in the similar or different shape, dimension and configuration as the socket. In a particular embodiment, the fastener is an O-ring coupled to the socket for securing the weight in the socket. In another aspect, the fastener is a threaded fastener. In one variation of the above, the fastener further comprises a retaining member coupled to the fastener for retaining the weight in the socket. In another aspect, the retaining member is a substantially coaxial annular member, square member or rectangular member where at least a portion of the retaining member overlaps with the socket opening to retain the weight. In another aspect, the wheel assembly comprises at least one fastener for retaining the weight in the socket. In yet another aspect, the fastener is a spring loaded retainer that retains the weight in the socket. In a particular aspect of the above, the fastener comprises a spring loaded retainer comprising an engaging element and a biasing member for retaining the weight in the socket. In another aspect, the cylindrical wall further comprises a through hole allowing air to pass through. In one variation, the through hole is coupled with an adjustable air release valve for regulating the flow of air through the through hole. In another aspect, the fastener comprises a quick-change threaded faster coupled with a retainer member for retaining the weight in the socket. In one variation, the cylindrical wall is concave. In a particular variation, the main body comprises a first portion and a second portion configured to provide a variable width of the main body, wherein the first and second portion is configured with one or more removable spacers between the first portion and the second portion for adjusting the width of the main body. 
         [0006]    In another embodiment, there is provided a wheel assembly comprising: a wheel comprising a main body, a substantially cylindrical wall, a front hub face comprising a central is portion connecting a hub to an outer rim, wherein the front hub face comprises a plurality of sockets for receiving a plurality of removable weights, a back face comprising a back central portion connecting the hub to the back outer rim, wherein the back face further comprising a stop for preventing the weights from moving in an axial direction toward the back face of the wheel; the rim comprising a front bead lock fastened to the front hub face of the main body of the wheel for securing the inside edge of a tire to the rim, and a back bead lock fastened to the back face of the main body for securing the inside edge of the tire to the rim; the wheel assembly comprising at least one fastener for securing the weighs in the sockets on the main body of the wheel, and further comprising a central insert comprising a central opening and configured to be axially adjustable and secured with the central opening of the wheel. In a particular embodiment, the central insert is configured with complementary thread on the central opening of the wheel and adjustable to move the central insert in a variable axial position. In one variation, the central insert is coupled to the hub with a plurality of adjustable threaded fasteners for adjusting and changing the distance between the front wheels or the distance between the back wheels. 
         [0007]    In another embodiment, there is provided a method for maintaining stability of a vehicle for traversing off road terrain, the method comprising the lowering of the central gravity of the vehicle by incorporating a wheel assembly comprising a front hub face comprising a plurality of sockets for receiving a plurality of removable weights. In one variation of the method, the wheel assembly comprises: a wheel comprising a main body, a substantially cylindrical wall, a front hub face comprising a central portion connecting a hub to an outer rim, wherein the front hub face comprises a plurality of sockets for receiving a plurality of removable weights, a back face comprising a back central portion connecting the hub to the back outer rim, wherein the back face further comprising a stop for preventing the weights from moving in an axial direction toward the back face of the wheel; the rim comprising a front bead lock fastened to the front hub face of the main body of the wheel for securing the inside edge of a tire to the rim, and a back bead lock fastened to the back face of the main body for securing the inside edge of the tire to the rim; and the wheel assembly comprising at least one fastener for securing the weighs in the sockets on the main body of the wheel. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    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. 
           [0009]      FIG. 1  is an isometric view of a radio-controlled vehicle. 
           [0010]      FIG. 2  is an exploded view of a tire assembly including a foam insert and an adjustable weighted vehicle wheel assembly according to an exemplary embodiment. 
           [0011]      FIG. 3  is an exploded view of a weighted rim according to an exemplary embodiment. 
           [0012]      FIG. 4  is a front view of the weighted rim of  FIG. 3  with one of the removable weights and the associated retainers removed. 
           [0013]      FIG. 5  is a side view of the weighted rim of  FIG. 3 . 
           [0014]      FIG. 6  is a cross-section of the weighted rim of  FIG. 5  taken along line  7 - 7  showing a retention system for a weight according to an exemplary embodiment. 
           [0015]      FIG. 7  is a detailed cross-section of the weighted rim of  FIG. 7 . 
           [0016]      FIG. 8  is a cross section of the weighted rim of  FIG. 5  taken along line  9 - 9  showing the interaction of a retention system with a weight according to an exemplary embodiment. 
           [0017]      FIGS. 9A-9C  are cross-section views taken along line  10 - 10  showing a hex core insert coupled to the rim according to several different embodiments to adjust the distance between wheels. 
           [0018]      FIGS. 10A and 10B  are front and rear isometric view of a weighted rim for a wheel according to an exemplary embodiment. 
           [0019]      FIG. 11  is a cross-section view of the weighted rim of  FIG. 10A  taken along line  11 - 11 . 
           [0020]      FIG. 12  is a side view of an adjustable width rim according to an exemplary embodiment. 
           [0021]      FIG. 13  is an exploded isometric view of the adjustable width rim of  FIG. 12 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0022]    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. 
         [0023]    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. 
         [0024]    The frame  12  is coupled to a multitude of wheels  20  (generally four) with a suspension  14 . According to 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 provided 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. 
         [0025]    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. 
         [0026]    The tire  24  includes an annular side wall  26  that is coupled to the rim  22  and a tread  28  that is configured to contact 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 vehicles, such as an RC model vehicle  10  are not filled with pressurized air. Instead, a foam support  29  is provided within the tire  24 , between the tire  24  and the rim  22 . The foam support  29  is a is compressible body that allows the tire  24  to deform 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  29  is formed from a closed-cell foam such as a urethane foam. 
         [0027]    Referring now to  FIGS. 3-7 , a rim  22  is shown according to an exemplary embodiment that is configured to receive a plurality of weights  50  to selectively increase the mass of the wheel  20  and lower the center of gravity of the vehicle. The rim  22  comprises a main body  30 , bead locks  40  coupled to the main body  30 , removable weights  50 , and a central insert  60 . 
         [0028]    The main body  30  comprises a cylindrical wall  32  surrounding a hub  34 . The hub  34  includes a central opening  36  that receives the vehicle axle  15 . A multitude of sockets  38  (e.g., hollows, openings, slots, cavities, bores, etc.) are provided in the hub  34  between the central opening  36  and the cylindrical wall  32 . The sockets  38  receive weights  50  and reduce the mass of the rim  22  when the weights  50  are absent be reducing the amount of material comprising the hub  34 . 
         [0029]    According to an exemplary embodiment, the main body  30  is formed from a metal such as aluminum. The main body may be formed in a variety of ways, including by machining or by casting. According to other exemplary embodiments, the main body may be formed or an injection molded polymer. 
         [0030]    As shown in  FIG. 10A-11  through holes  33  may be provided through the cylindrical wall  32 . Through holes  33  allow air to pass through the cylindrical wall between the outside atmosphere and the interior of the tires  24 . Referring especially to  FIG. 11 , according to one exemplary embodiment, the through hole  33  is an L-shaped channel with a radial portion  44  and an axial portion  46 . A separate threaded hole  47  intersects the through hole  33  and receives a set screw  48 . The set screw  48  may be advanced into the threaded hole such that it is disposed partially in the through hole  33 , partially or completely obstructing the flow of air through the through hole  33 . In this way, a user may adjust the set screw  48  and control or fine tune the amount of air that is allowed to pass through the cylindrical wall between the outside atmosphere and the interior of the tires. 
         [0031]    Bead locks  40  are coupled to either end of the main body  30 , trapping the inside edges  27  (e.g., “beads”) of the tire  24  in a groove  42  formed between the bead locks  40  and the main body  30 . The bead locks  40  are generally annular bodies that are aligned with the cylindrical outer portion of the main body  30  without obscuring or covering the hub  34 . According to an exemplary embodiment, the bead locks are each coupled to the main body  30  with fasteners, such as socket-headed threaded fasteners  70 . 
         [0032]    Weights  50  may be selectively inserted and retained in the sockets  38  to increase the mass of the wheel  20  and lower the center of gravity of the vehicle. By lowering the center of gravity, the stability of the vehicle  10  is increased and the severity of the slope (i.e., slopes approaching vertical) may be overcome by the vehicle  10 . In one particular embodiment, six weights  50  may be inserted into six corresponding sockets  38  provided symmetrically about the hub  34 . To keep the wheel  20  balanced, two, three, four or six weights  50  may be added symmetrically to the rim  22 . For example, if two weights  50  are used, they are inserted to sockets  38  opposite of each other. By allowing a different amount of weights  50  to be added to the rim  22 , a user may fine tune the mass of the wheel  20 . 
         [0033]    In one embodiment, the weights  50  are inserted into the sockets  38  from one side of the rim  22  (e.g., the outboard side of the rim  22 ). The weights  50  may be inserted into the main body  30  before the wheels  20  are coupled to the vehicle axle  15  or after the wheels  20  are mounted. The movement of the weights  50  in the axial direction is limited by a stop, such as a ledge  39  (e.g., protrusion, rim, lip, etc.) extending inward from the side walls of the socket  38 . The weights  50  are held in place by retainers, shown in  FIG. 3  as threaded fasteners  72 . The threaded fasteners  72  engage threaded openings  74  in the hub  34  proximate to the sockets  38  such that the heads of the fasteners  72  overlap the sockets  38  on either side of the threaded opening  74  and restrict the movement of a weight  50  inserted into the socket  38 . Therefore, each fastener  72  helps to retain weights  50  in two sockets  38  and each weight  50  is retained by two fasteners  72 . In this way, a missing fastener  72  that is lost (i.e. due to insufficient tightening) or simply not coupled to the hub  34  does not allow any weights  50  to fall or be shaken loose from a socket  38 . Rather, up to three fasteners  72 , provided they are in alternating openings  74 , may be absent while still retaining all the weights  50 . 
         [0034]    According to other exemplary embodiments, each fastener  72  may only retain one weight  50 , as shown in  FIGS. 10A and 10B . According to other exemplary embodiments, an annular retaining member similar to the bead locks  40  and concentric with the bead locks  40  may be coupled to the hub  34  (e.g., with a screw) such that it overlaps the sockets  38  and retains the weights  50  in the sockets  38 . According to still other exemplary embodiments, the outboard bead lock  40  may extend inward such that it overlaps the sockets  38  and retains the weights  50  in the sockets  38 . 
         [0035]    According to yet another exemplary embodiment, referring to  FIGS. 5-8 , a spring-loaded retainer  80  may be provided to retain the weights  50  in the sockets. As shown best in  FIGS. 7-8 , the retainer  80  comprises an engaging element, such as a ball bearing  82  and a biasing member, shown as a coil spring  84 . The ball bearing  82  and the spring  84  are housed in shaft or bore  86  that extend from the outer cylindrical wall  32  of the main body to one of the sockets  38  formed in the hub  34 . The end of the bore  86  proximate to the socket  38  is chamfered or otherwise shaped such that the opening  87  in the socket  38  has a diameter that is smaller than the diameter of the bore  86 . The bore  86  is at least partially threaded and receives a correspondingly threaded member such as a set screw  88 . The spring  84  is compressed between the set screw  88  and the ball bearing  82 . The spring  84  biases the ball bearing  82  towards the socket  38  and extends partially through the opening  87 . Because the ball bearing  82  has a diameter that is larger than the diameter of the opening  87 , only a portion of the ball bearing  82  is allowed to extend into the socket  38  while the ball bearing  82  is still retained in the bore  86 . 
         [0036]    The weight  50  received in the socket  38  includes a groove  76  (e.g., notch, channel, trough, concavity, slot, etc.) that is generally aligned with the opening  87  and the ball bearing  82 . When the weight  50  is inserted into the socket  38 , the ball  82  is pushed out of the socket  38 . Once the weight  50  is fully seated (e.g., contacting the ledge  39 ), the groove  76  is aligned with the opening  87  and the ball bearing  82  is biased back out through the opening  87  by the spring  84 . The ball  82  engages the groove  76  to retain the weight  50  in the socket  38 . 
         [0037]    According to an exemplary embodiment, the weights  50  are cylindrical bodies formed of a metal. The weights  50  may be formed from a variety of metals or alloys including, but not limited to, such as aluminum, steel, brass, tungsten, or lead. A user may use several different is sets of weights  50  of different materials to add a desired amount of mass to the rim  22 . For instance, weights of a relatively dense material such as lead may be used to increase the mass of the rim more than weights of a less dense material such as aluminum. According to other exemplary embodiments, a user may mix weights formed of different materials. For example, a user may use weights of two different materials in alternating sockets to add a mass that is in between the mass that would be added with all weights of either of the materials. 
         [0038]    Referring now especially to  FIGS. 3 ,  9 A,  9 B and  9 C, an insert  60  is coupled to the hub  34  proximate to the central opening  36 . According to an exemplary embodiment, the insert is coupled to the hub  34  with removable threaded fasteners. The insert  60  includes a central opening  62  (e.g., hollow, bore, recess, etc.) and a socket  64  that are each aligned with the central opening  36  in the hub  34  and are separated by an inwardly extending ledge  66  (e.g., lip, protrusion, etc.). When the wheel  20  is coupled to the axle  15 , the insert  60  receives a coupler  19  to rotationally lock the wheel  20  to the axle  15 . A threaded end  17  of the axle  15  extends through the central openings  36  and  62 . A fastener such as a nut (not shown) is threaded onto the threaded end  17  until it is seated on the ledge  66  to axially couple the wheel  20  to the axle  15 . 
         [0039]    The distance between the two wheels  20  on the axle  15  may be adjusted by changing the relative distance between the ledge  66  and the rear of the main body  30  of the rim  22 . To this end, different inserts  60  may be provided to change the width of vehicle  10  (e.g., the distance between the front wheels  20  or between the rear wheels  20 ). With a relatively deep insert  60  ( FIG. 9A ) the distance  68 A between the ledge  66  and the rear of the main body  30  is shorter than the distance  68 C between the ledge  66  of a relatively shallow insert  60  and the rear of the main body  30  ( FIG. 9C ). An insert  60  of an intermediate depth has an intermediate distance  68 A between the ledge  66  and the rear of the main body  30 . According to an exemplary embodiment, using deep inserts  60  ( FIG. 9A ) instead of a shallow inserts  60  ( FIG. 9C ) increases the wheel-to-wheel width of the vehicle by approximately 0.5 inches. Such a flexibility in wheel-to-wheel width is desirable in competitions involving rock crawling vehicles  10  where a wider distance between the front wheels  20  is desirable for increased stability, while a narrower distance between rear wheels  20  is desirable for increased maneuverability around markers and obstacles. 
         [0040]    While the weights  50  are shown in the FIGURES as cylindrical bodies, according to is other exemplary embodiments, the weights may be a wide variety of other shapes (i.e., prismatic, cubic, spherical, bullet-shaped, etc.). The weights may be solid, as shown in the FIGURES, or may be at least partially hollow. 
         [0041]    The main body  30  may be configured to have a variable width. Reducing the width of the main body  30  in turn reduces the space between the beads  27  of the tire  24 . This creates a bulge on the side walls  26 . Narrowing the rim  22  may allow the vehicle  10  to have better traction. Narrowing the rims  22  also pulls the inside of the tires  24  inward, allowing more turning while avoiding the suspensions links. 
         [0042]    According to one exemplary embodiment, shown in  FIGS. 12-13 , the main body  30  comprises a first portion  92  and a second portion  94 . One or more removable spacers  90  are provided between the first portion  92  and the second portion  94  to vary the overall width of the rim  22 . As shown, the spacers  90  may be individual washer-shaped bodies that are provided concentrically with fasteners  70  to couple one of the bead locks  40  to the second portion  94  of the main body. The fasteners  70  pass through openings  93  in the bead lock  40  and first portion  92  of the main body and through the removable spacers  90  to engage threaded holes  95  in the second portion  94 . The second portion  94  includes a series of bosses  96  (e.g., projections, etc.) that form sockets  38  for the removable weights  50  and locate the spacers  90 . The first portion  92  interlocks with the bosses  96  to prevent rotation of the first portion relative  92  to the second portion  94 . Preventing rotation of the first portion relative  92  to the second portion  94  avoids applying a damaging torque the tire  24 . 
         [0043]    While  FIGS. 12-13  show a rim with a series of six stacks of cylindrical spacers, with each stack including four spacers, it should be appreciated that many variations are possible. For instance, instead of separate stacks of spacers, the spacers could be annular members similar in shape to the first portion  92  of the main body or the bead locks  40 . According to still other exemplary embodiments, more or fewer spacers of varying thicknesses may be provided to allow a user to achieve a wide range of rim widths. 
         [0044]    As utilized 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 is 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. 
         [0045]    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). 
         [0046]    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. 
         [0047]    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. 
         [0048]    It is important to note that the construction and arrangement of the wheel assembly 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.

Technology Category: 1