Patent Abstract:
The present invention discloses a tire for a conventional rim, having two exterior sidewalls and two interior walls, and an annular tread portion with a center, an interior and an exterior surface. The first and second sidewalls extend radially from the tread portion. Each sidewall has a perimeter edge which is sized and configured to be coupled to a wheel hub. The first and second interior walls extend from substantially near the perimeter edge of the first and second sidewalls, respectively, to a predetermined location on the interior surface of the tread portion. The first and second interior walls being attached to the tread portion to transfer loads applied to the tire by alternatively flexing and compressing in response to the loads applied to the tire.

Full Description:
FIELD OF THE INVENTION 
     This invention pertains to motor vehicle tires, and more particularly to a tire having interlocking interior sidewalls. 
     BACKGROUND OF THE INVENTION 
     Conventional pneumatic tires are generally of a tubeless construction. A single puncture or hole in the outer sidewall or the tread will cause the tire to deflate, leaving the hapless driver to either change the tire if a spare is available, or refrain from using the automobile for risk of damaging the tire rim. Conventional tires typically have two exterior sidewalls without internal structural bracing. Such a tire is susceptible to lateral deformation due to high lateral loads associated with cornering too fast. This may lead to a blowout, thereby posing a safety risk, or reducing the life of the tire due to premature wear. 
     Prior solutions to the above-identified problems include the addition of an additional tire to the vehicle to increase the load carrying capacity of the tire, or increase the tire tread contact area with the surface for more stability. Although such solutions are effective at increasing vehicle load capacity and stability, they are not without their problems. First, adding at least one additional tire to a vehicle increases both the complexity and, therefore, the cost of the vehicle. Second, wider tire tread area may require a non-standard sized wheel hub and, therefore, is more expensive than a vehicle having a conventional sized wheel. Finally, such solutions may or may not increase the resistance of the sidewalls to lateral loads. 
     Therefore, there exists a need for a tire having increased load capacity, tread area and structural integrity to resist deformation, wherein such a tire is both cost effective and sized to fit conventional wheel hubs. 
     SUMMARY OF THE INVENTION 
     The present invention discloses a tire for a conventional rim, having two exterior sidewalls and two interior walls, and an annular tread portion with a center, an interior and an exterior surface. The first and second sidewalls extend radially from the tread portion. Each sidewall has a perimeter edge which is sized and configured to be coupled to a wheel hub. The first and second interior walls extend from substantially near the perimeter edge of the first and second sidewalls, respectively, to a predetermined location on the interior surface of the tread portion. The first and second interior walls being attached to the tread portion to transfer loads applied to the tire by alternatively flexing and compressing in response to the loads applied to the tire. 
     In a preferred embodiment, the tire has an annular tread portion having a center, an interior surface and an exterior surface. The tread portion has a first and a second region defined on the exterior surface of the tread portion forming a groove between the first and the second regions. The tire also includes a first and second sidewall extending radially from the tread portion, each of the sidewalls having a perimeter edge defining part of a bead portion. The tire also includes a first and a second interior wall. The first and second interior wall form a first and second bead, each bead is sized and configured to be coupled to a wheel hub. The first and second interior wall further include concave and convex regions extending on the wall therethrough to react to loads applied to the tire. The first and second interior wall extend diagonally from each of the respective beads to a predetermined location on the interior surface of the tread portion where each interior wall is attached to a region opposite. 
     In another embodiment, the tire may also include a traction ring embedded with studs, wherein the traction ring is sized and configured to be selectively attached between a groove separating the two tread regions. 
     In yet another embodiment, the tire has one annular tread portion with an interior and an exterior surface, a first and second sidewall extending radially from the tread portion, each sidewall having a perimeter edge forming part of a bead portion, sized and configured to be selectively coupled to a wheel hub, and a first and second interior wall, the first and second interior walls having varying radii of curvature forming concave and convex regions, the first and second interior walls forming a part of each of the respective beads. The first and second interior walls intersect one another above the tread portion forming at least three interior chambers. The first and second interior walls extend along a diagonal from the bead to the corresponding diagonal corner at the tread portion, where they are attached to the interior surface of the tread portion. 
     In still yet another embodiment, the tire has one annular tread portion, a first and second sidewall extending radially from the tread portion, each sidewall having a perimeter edge forming a part of a bead portion, sized and configured to be selectively coupled to a wheel hub, and a first and second interior wall, the first and second interior wall being joined at a center region of the tread portion. The first and second interior walls having varying radii of curvature forming concave and convex regions. The first and second interior walls forming a part of each of the respective beads. The first and second walls generally follow a diagonal from each respective bead to the center region of the tread portion. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The foregoing aspects and many of the attendant advantages of this invention will become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein: 
     FIG. 1 shows a cross sectional view of one embodiment of a tire for a vehicle constructed in accordance with the present invention. 
     FIG. 2 shows the tire of FIG. 1 with a portion of the tire cutaway for clarity and a traction ring disposed around the perimeter of the tire. 
     FIG. 3 shows a cross sectional view of an alternate embodiment of a tire constructed in accordance with the present invention. 
     FIG. 4 shows a cross sectional view of a second alternate embodiment of a tire constructed in accordance with the present invention. 
     FIG. 5 shows a cross sectional view of the tire of FIG. 1 as it would deflect under certain loading conditions. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIGS. 1 and 2 show one embodiment of a tire constructed in accordance with the present invention. The tire includes an annular tread portion  100  having a lateral tread region  102  and a medial tread region  104 . The portion of the tread  100  which contacts the ground surface may be provided in any of a number of configurations for this and all embodiments constructed in accordance with the present invention. The lateral  102  and medial  104  tread regions each include an inside  106 ,  108  and an outside  110 ,  112  region, respectively. The tread portion  100  is divided by a groove  114 . It should be noted that the terms “lateral” and “medial” are intended to be descriptive and not for purposes of limiting the invention. Thus, it should be understood that although the invention is described as having lateral and medial tread regions, other embodiments, such as a tire having more or less tread regions, are also within the scope of the present invention. 
     The tire also has a lateral exterior sidewall  116 , a medial exterior sidewall  118  opposite of the exterior sidewall  116 , a lateral interior sidewall  120 , and a medial interior sidewall  122 . The upper portion  124  of the medial exterior sidewall  118  and the upper portion  126  of the medial interior sidewall  122  define a medial bead  128 , sized and configured to be selectively coupled to a conventional rim  130 . Similarly, the upper portion  132  of the lateral exterior sidewall  116  and the upper portion  134  of the lateral interior sidewall  120  define a lateral bead  136 , sized and configured to be selectively coupled to a conventional rim  130 . A tire constructed in accordance with the present invention may be applied to rims of all sizes and configurations. Lateral exterior sidewall  116  and medial exterior sidewall  118  extend radially from each of the respective beads  136  and  128  to connect to the tread portion  100 , where a lower portion  154  of the lateral exterior sidewall  116  is connected to a lateral comer  156  of the tread portion  100  and a lower portion  158  of the medial exterior sidewall  118  is connected to a medial comer  160  of the tread portion  100 . 
     The lateral interior sidewall  120  generally extends diagonally from the lateral bead  136  to the respective opposite inside region  108  of the medial tread region  104  where it is attached thereto. The medial interior sidewall  122  generally also extends diagonally from the medial bead  128  to the respective opposite inside region  106  of the lateral tread region  102  where it is attached thereto. The interior sidewalls are configured to form two intersecting “S” patterns. The interior sidewalls  120 ,  122  have varying radii of curvature defining concave  138 ,  140  and convex  142 ,  144  regions, defining portions of conic shapes, in particular those regions may be said to be parabolic. These regions may be selectively designed to determine the path of flexing when loads are applied to the tire. The interior sidewalls  120 ,  122  define a first  146  and second  148  chamber with the exterior sidewalls  116 ,  118  and the two tread regions  102 ,  104 . The chambers  146 ,  148  defined by the exterior  116 ,  118  and interior  120 ,  122  sidewalls and tread regions  102 ,  104  may be filled with air, jelly, or rubber ball bearings or any other suitable compressible material. The chambers of any of the embodiments of the present invention may be filled with like materials. A tire constructed in accordance with the present invention may also include holes or voids within the first and second interior walls so that chambers are in communication with one another. 
     As seen best by referring to FIG. 1, the tire has a groove  114  defined by the lateral tread region  102  and the medial tread region  104 . The groove  114  is adapted to receive a traction device  150  in the shape of a ring. The traction device  150  may be fitted with studs  152  or other traction members to increase traction on road surfaces. Suitable uses include ice, mud, sand, etc. A person of ordinary skill in the art would readily appreciate any of the multitude of stud-like members suitable for a traction device ring. 
     Referring now to FIG. 3, a first alternate embodiment of a tire constructed in accordance with the present invention will now be described in greater detail. For purposes of illustration, only a cross sectional view of a tire constructed in accordance with the present invention is shown. It should be readily apparent that a tire is meant to have an annular shape. This embodiment is identical in materials and operation as the first embodiment described above with the exception that the current alternate embodiment includes an annular tread portion  200  with a single tread region. It should be readily apparent that the ground contact surface of the tread portion  200  may have any of a number of configurations. In this embodiment, the tire is constructed from a lateral exterior sidewall  202 , a medial exterior sidewall  204  opposite the lateral exterior sidewall  202 , a lateral interior sidewall  206 , and a medial interior sidewall  208 . The upper portion  210  of the medial exterior sidewall  204  and the upper portion  212  of the medial interior sidewall  208  define a medial bead  214 , sized and configured to be selectively coupled to a conventional rim  216 . The upper portion  218  of the lateral exterior sidewall  202  and the upper portion  220  of the lateral interior sidewall  206  define a lateral bead  222  to fit a conventional rim  216 . A tire constructed in accordance with the present invention may be applied to rims of all sizes and configurations. Lateral exterior sidewall  202  and medial exterior sidewall  204  extend radially from each of the respective beads  222  and  214 , to connect to the tread portion  200 , where a lower portion  248  of the lateral exterior sidewall  202  is connected to a lateral corner  226  of the tread portion  200  and a lower portion  250  of the medial exterior sidewall  204  is connected to a medial comer  224  of the tread portion  200 . The lateral interior sidewall  206  generally defines a diagonal from the lateral bead  222  to the respective opposite medial corner  224  of the tread portion  200  where it is attached thereto. The medial interior sidewall  208  generally defines a diagonal from the medial bead  214  to the respective opposite lateral corner  226  of the tread portion  200  where it is attached thereto. The interior sidewalls  206 ,  208  have varying radii of curvature defining concave  228 ,  230  and convex  232 ,  234  regions, defining portions of conic shapes, in particular, these regions may be said to be parabolic. The lateral interior sidewall  206  and the medial interior sidewall  208  intersect one another in an intersection region  236  proximate to the lower portions  238 ,  240  of each respective interior sidewall  206 ,  208  thereby forming three chambers  242 ,  244 , and  246 , with the exterior sidewalls  202 ,  204  and the tread portion  200 . 
     Referring now to FIG. 4, a second alternate embodiment of a tire constructed in accordance with the present invention will now be described in greater detail. This embodiment is identical in materials and operation as the first embodiment described above with the exception that the current alternate embodiment includes a tread portion  300  with a single tread region. It should be readily apparent that the ground contact surface of the tread portion  200  may have any of a number of configurations. In this embodiment, the tire is constructed from a lateral exterior sidewall  302 , a medial exterior sidewall  304 , a lateral interior sidewall  306 , and a medial interior sidewall  308 . The upper portion  310  of the medial exterior sidewall  304  and the upper portion  312  of the medial interior sidewall  308  define a medial bead  314  sized and configured to be selectively coupled to a conventional rim  316 . The upper portion  318  of the lateral exterior sidewall  302  and the upper portion  320  of lateral interior sidewall  306  define a lateral bead  322  sized and configured to be selectively coupled to a conventional rim  316 . A tire constructed in accordance with the present invention may be applied to rims of all sizes and configurations. Lateral exterior sidewall  302  and medial exterior sidewall  304  extend radially from each of the respective beads  322  and  314  to connect to the tread portion  300 , where a lower portion  338  of the lateral exterior sidewall  302  is connected to a lateral corner  340  of the tread portion  300  and a lower portion  342  of the medial exterior sidewall  304  is connected to a medial corner  344  of the tread portion  300 . The lateral interior sidewall  306  generally defining a diagonal from the lateral bead  322  to a center region  324  of the tread portion  300  where it is attached thereto. The medial interior sidewall  308  generally defining a diagonal from the medial bead  314  to the center region  324  of the tread portion  300  where it is attached thereto. The interior sidewalls  306 ,  308  have varying radii of curvature defining concave  326 ,  328  and convex  330 ,  332  regions, defining portions of conic shapes, in particular, these regions may be said to be parabolic. The interior sidewalls  306 ,  308  form a first  334  and second  336  chamber with the exterior sidewalls  302 ,  304  and the tread portion  300 . 
     Those persons of ordinary skill can readily apply the tires of the present invention to the conventional art of tire-making. 
     For illustration purposes, use of the tire will now be described with reference to FIG. 5. A tire constructed in accordance with the present invention is shown in phantom in a non-deflected state  400 . Shown in bold is the same tire in a deflected state  402 . A generic feature of all embodiments of a tire constructed in accordance with the present invention is the diagonally sloping interior sidewalls ( 404 ,  406  phantom)  408 ,  410  bold. The interior sidewalls generally have concave and convex predeflected regions. The shape of the interior sidewalls generally will define the load paths when the tire is under compressive or tensile loads. As the tire deforms, it is important to note that the interior sidewalls are predetermined to bend in the direction of concavity when placed under compressive loads as shown by interior sidewall  408 , and the interior sidewalls may flatten out when placed under tensile loads as shown by interior sidewall  410 . However, neither bending or flattening or any sort of deformation increases the length of the interior or exterior sidewalls. A distance measured from the bead to the tread portion along the centerline of any sidewall, exterior as well as interior, will remain substantially constant throughout any tire deflection. Thus, for example, distance A-B along the centerline in its non-deflected state remains substantially the same as in its deflected state A′-B′. This holds true for any two points on any centerline of the interior or exterior sidewalls. The concave and convex shape also imparts a deformable, spring-like action that snaps the tire back into shape when lateral forces are removed. The interior sidewalls also allow vertical forces, such as heavy loads from cargo carrying vehicles, to be transferred or channeled from the rim to the ground. Such vertical loads are transferred through the exterior sidewalls to the inside comer of the tire and through the interior sidewalls to the outside comer of the tire and vice versa. The combination of four sidewalls provides greater load bearing capacity and more effective comer traction between the vehicle and the ground. 
     When the tire is under static or moving vertical loads, the interior sidewalls brace the exterior sidewalls to resist deflection, thereby providing greater traction and stability. 
     In some embodiments, the tire is provided with a tread portion having two tread regions. It is generally known that wide tires provide more stable cornering. However, an advantage of the tire of the present invention is to widen the effective width of the tire while maintaining minimal surface area contact with the ground, thereby reducing rolling friction and improving fuel economy. 
     In addition, the tire of the present invention may have a plurality of chambers. Each chamber may have a separate fill nozzle. In this manner, deflation of one chamber will not deflate the entire tire, allowing the user to continue driving. Alternatively, the tire may have holes in the interior sidewalls to equalize the air pressure. 
     Materials of construction for a tire constructed in accordance with the present invention are similar for conventional tires. A person of ordinary skill in the art would readily know and comprehend all suitable materials to construct a tire in accordance with the present invention. 
     While the preferred embodiment of the invention has been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention.

Technology Classification (CPC): 8