Abstract:
An inner tire used in a dual-chambered tire is provided by an inner tire in which an exterior sidewall of tire provides for two annular rows of overlapping raised facets that extend above the exterior surface of the tire. Each facet defines a right angle with respect to the adjacent sidewall of the tire and provides for an elevated surface having a substantially uniform height with respect to the underlying tire exterior surface. The facets further define a plurality of gaps and passageways that have a constant height and through which pressurized air may flow during the inflation of the outer tire. The air gaps and air passageways defined by the facets have a sufficient depth that the resulting passageways do not collapse when the pressurized inner tire is in engagement with the pressurized outer tire.

Description:
FIELD OF THE INVENTION  
         [0001]    This invention is directed towards a multi-chambered tire. More particularly, this invention relates to a pneumatic tire that is positioned within an interior of an outer pneumatic tire.  
         BACKGROUND OF THE INVENTION  
         [0002]    A tire assembly often employs an inner pneumatic structure, such as a tire, which is mounted on a rim and is positioned axially inward of the bead portion of an outer pneumatic tire.  
           [0003]    When assembled, the inner tire of a tire assembly is positioned within the outer tire and helps stabilize a vehicle should the outer tire lose pressure. The wheel arrangement provides for a tire assembly having outer and inner air chambers, the outer chamber being defined by the space between the radially outer surface of the inner tire and the radially inner surface of the outer tire. Similarly, the inner chamber is formed by the inner surface of the inner tire and the associated wheel rim.  
           [0004]    It is desirable to maintain a pressure within the inner air chamber that is greater than the pressure within the outer air chamber. The pressure differential between the inner tire and the outer tire facilitates the seating of the outer tire bead to the wheel rim. In addition, the inner engagement between the inner tire exterior surface and the interior surface of the outer tire results in an airtight seal. Accordingly, it is necessary to maintain an air inflation pathway between the interior surface of the exterior tire and the exterior surface of the inner tire. While the prior art provides for various tire assemblies having an inner tire and outer tire combination, there remains room for variation and improvement within the art.  
         SUMMARY OF THE INVENTION  
         [0005]    It is one aspect of the present invention to provide a pneumatic tire that may be used as an inner tire insert within the interior of a second tire.  
           [0006]    It is another aspect of the present invention to provide for an interior pneumatic tire that defines a non-collapsible air passageway through which the associated outer tire may be reliably inflated when the inner tire and outer tire are mounted on a wheel.  
           [0007]    In another aspect, the invention resides in an inner tire for use within an interior of an outer tire, the inner tire providing a plurality of raised projections, each projection providing a substantially flat, uniform surface for engagement of the inner surface of the exterior tire.  
           [0008]    It is yet another aspect of the present invention to provide an inner tire having at least two distinct annular rows of raised facets that extend above the underlying exterior surface of the tire. A channel formed between each pair of facets within each respective row further defines a radially extending air passageway. The innermost row of facets are positioned within an overlapping, staggered arrangement with respect to the outermost row of facets. An annular space defined between the first row of facets and the second row of facets provides a circumferential air passageway that extends along the exterior surface of the inner tire. A similar circumferential passageway is defined between the proximal edge of the first row of facets and the bead heel surface.  
           [0009]    In yet another aspect, the invention resides in a pneumatic inner liner for a tire comprising: a pneumatic structure having an interior surface, an exterior surface, and a sidewall portion extending radially inward from each axial edge of a cover portion to a respective bead portion, the sidewall having an exterior surface further defining a plurality of facets defining a first annular row, each of the facets extending above an outer surface of the liner a uniform height and each facet having a plurality of edge walls which form a substantially right angle with respect to the sidewall surface; a plurality of first gaps defined between each of the plurality of facets; a plurality of second facets defining a second annular row, each of the second plurality of facets positioned on an exterior of the sidewall between a bead of said liner and said first annular row of facets, each of the second plurality of facets extending above an outer surface of the liner and further defining a plurality of edge walls, each of said edge walls forming a generally right angle with respect to the exterior surface of the liner; a plurality of second gaps defined between each of the facets of the second annular rows, a first circumferential passageway defined between the first annular row and the second annular row, the first circumferential passageway in fluid communication with the plurality of first gaps and the plurality of second gaps; and, a second circumferential passage defined between a proximal edge of the second row of facets and a bead heel surface, the second circumferential passageway being in fluid communication with the plurality of gaps of the second row of facets.  
           [0010]    These and other features, aspects, and advantages of the present invention will become better understood with reference to the following description and appended claims. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]    A full and enabling disclosure of the present invention, including the best mode thereof, to one of ordinary skill in the art, is set forth more particularly in the remainder of the specification, including reference to the accompanying drawings.  
         [0012]    [0012]FIG. 1 is a cross-section view of the inner tire according to the present invention shown mounted on a rim and in relation to an outer tire;  
         [0013]    [0013]FIG. 2A is an enlarged view in partial section of the bead and sidewall portion of the inner tire and outer tire mounted on a tire rim;  
         [0014]    [0014]FIG. 2B is an enlarged view similar to FIG. 2A setting forth additional details of the bead and sidewall portions of the inner tire and outer tire.  
         [0015]    [0015]FIG. 3 is a side elevation view of the exterior surface of the inner tire as seen along line  3 - 3  of FIG. 1; and  
         [0016]    [0016]FIG. 4 is an edge view of the inner tire taken along line  4 - 4  of FIG. 3.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0017]    Reference now will be made in detail to the embodiments of the invention, one or more examples of which are set forth below. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment, can be used on another embodiment to yield a still further embodiment. Thus, it is intended that the present invention cover such modifications and variations as come within the scope of the appended claims and their equivalents. Other objects, features, and aspects of the present invention are disclosed in the following detailed description. It is to be understood by one of ordinary skill in the art that the present discussion is a description of exemplary embodiments only and is not intended as limiting the broader aspects of the present invention, which broader aspects are embodied in the exemplary constructions.  
         [0018]    In describing the various figures herein, the same reference numbers are used throughout to describe the same material, apparatus or process pathway. To avoid redundancy, detailed descriptions of much of the apparatus once described in relation to a figure is not repeated in the descriptions of subsequent figures, although such apparatus or process is labeled with the same reference numbers.  
         [0019]    As used herein, the term “inner” means toward the inside of the tire and/or rim and the term “outer” means toward the exterior of the tire and/or rim.  
         [0020]    The term “axial” is used to refer to a direction which is parallel to the axis or rotation of the tire.  
         [0021]    The term “radial” is used to mean a direction toward or away from the axis or rotation of the tire.  
         [0022]    The term “lower” refers to the relative orientation of an exterior region of the tire closest to the bead portion.  
         [0023]    The term “upper” refers to the relative orientation of an exterior region of the tire which is radially spaced from the nearest bead portion of the tire.  
         [0024]    Referring first to FIG. 1, there is illustrated a pneumatic structure in the form of a tire  10  which is adapted for use as an inner pneumatic liner positioned within the interior cavity of a tire. The tire  10  defines an inner surface  12  and an outer surface  14 . Tire  10  defines an interior cavity  16  which, when secured to a wheel rim  100 , provides an air chamber for inflation of the tire  10  using a conventional inflation valve  110 . Tire  10  maintains its air pressure by an inner portion  18  seen here in the form of a butyl air containment barrier located along the interior surface  12  of the tire  10 .  
         [0025]    Tire  10  has a toroidal cross-section formed by a carcass  30 . The carcass construction is one which is standard within the industry. As seen in reference to FIGS. 2A and 2B, carcass  30  has at least one reinforced ply extending from a first bead portion  20  to an axially displaced second bead portion  22 . Each end  32  of the carcass  30  is anchored to a respective bead  20  or  22  and extends radially outward from the bead. A rubber cover portion  50 , as seen in reference to FIG. 1, comprises a width-wise portion of the tire that is analogous to the tread portion of a conventional tire. A sidewall portion  40  extends radially inward from each lateral edge of the cover  50  to the respective bead  20  or  22 .  
         [0026]    In reference to FIGS. 3 and 4, sidewall  40  defines an outer profile seen here in the form of an upper sidewall  42  and further defines an inner profile seen here in the form of a lower sidewall  44 . The surface of lower sidewall  44  recessed below a surface plane of the upper sidewall  42 . As seen in reference to FIGS. 3 and 4, the boundary between the upper sidewall  42  and the lower sidewall  44  is formed along reference line “B”. In one embodiment of the invention, the surface of the lower sidewall  44  is offset about 0.060 inches below a plane defined by the adjacent surface of the upper sidewall. The lower sidewall provides a support surface for two annular rows of facets comprised of individual facets  60  and  70  as will be described in further detail below. The dimensions of the lower sidewall are formed during curing from the dimensions of the curing ring. The upper sidewall dimensions are formed by the mold shell dimensions.  
         [0027]    As seen in FIGS. 3 and 4, the upper sidewall  42  defines a plurality of grooves  46  which extend from the edge of the upper sidewall  42  in a radial direction toward the cover portion  50 . Each groove  46  has a depth, relative to the upper side wall surface of about 0.060 inches and is in communication with a corresponding gap  48 , each gap  48  being defined between two adjacent raised facets  60 . A plurality of raised facets  60  form a first annular row of facets. Each facet  60  has a uniform height of about 0.125 inches above the lower sidewall surface  42  and provides a flat top surface  61 . Further, each facet edge wall forms a right angle with respect to the subtending surface of the lower sidewall.  
         [0028]    As best seen in reference to FIGS. 3 and 4, an outermost endwall  62  of each facet  60  terminates adjacent the lower edge of upper sidewall  42 . In a preferred embodiment, the height of facet  60  and facet end wall  62  is about 0.065 inches above the adjacent surface of upper sidewall  42 . Accordingly, a single right angle notch or step  64  is formed between the outermost edge of each facet end wall  62  and the adjacent upper sidewall  42 . As seen by this arrangement, groove  46  and gaps  48  form a continuous channel in a radial direction along the respective upper sidewall  42  and lower sidewall  44 .  
         [0029]    A second annular row of raised surface projections is provided by a plurality of individual facets  70 . Each facet  70  extends from a lower edge opposite a respective bead portion  20  or  22  and extends in a radial direction along the lower sidewall  44 . As seen in FIG. 3, each facet  70  is staggered with respect to the first row of facets  60  so that each facet  70  is opposite a gap  48  defined by the first row of facets.  
         [0030]    Each facet  70  defines a raised projection having a flat top surface  71 , as seen in FIG. 4, which extends above the exterior surface of the respective sidewall and bead portion of tire  10 . Adjacent the underlying bead, an proximal facet wall  72  is provided which forms a right angle with respect to the bead heel surface  26 . Each facet  70 , as it extends radially from the proximal wall  72 , rapidly increases to a desired thickness with respect to the adjacent exterior wall surface. Thereafter, each facet  70  extends radially outwardly at a uniform height of about 0.125 inches with respect to the lower sidewall surface. Between each facet  70 , a radially extending gap  74  is defined between the raised edgewalls of the adjacent facets  70 .  
         [0031]    As seen in FIG. 3, the distal portion of gap  74  and the proximal portion of gap  48  are in fluid communication along an annular passageway  80  defined between the second row of facets  70  and the first row of facets  60 . This arrangement facilitates the inflation of the exterior tire  90  by providing an air passageway which may enter through any gap  74  defined by the second row of facets  70 , the air passageway extending into the annular passage  80  and thereafter through one or more radial gaps  48 . With respect to any individual gap  48 , air flow may continue through the grooves  46 . Additionally, it is believed that as the air flow passes through gaps  48 , the air flow is no longer restricted to movement exclusively through groove  46  and may be released into the air chamber  92  defined between the exterior of inner tire  10  and the interior of outer tire  90 .  
         [0032]    As best seen in reference to FIG. 2B, one embodiment of the sidewall  40  of the inner tire  10  extends radially outwardly from the bead heel  26  a linear height “H” of 4.22 inches. The lower sidewall  44  extends a height “L” of 1.65 inches from the bead heel  26 , the upper sidewall  42  extending the remaining height “U” of 2.57 inches for a collective sidewall height of 4.22 inches.  
         [0033]    As best seen in reference to FIG. 2B, the floor of groove  46  can be coplanar with the surface of the lower sidewall  44 . In accordance with this invention, it is preferred that the radial length of end groove  46  extends to a point along the height of the sidewall that is about at least 50% of the total sidewall height. More preferably, groove  46  extends to a point about 60% of the total sidewall height so as to maintain an open air passageway between the inner and outer tires.  
         [0034]    With respect to the exemplary embodiment referenced in the figures, groove  46  has a radial length “G” of 0.75 inches and extends radially outwardly from the upper boundary of the lower sidewall to a point 2.40 inches along the sidewall. Accordingly, the outermost radial terminus of groove  46  extends 57% of the total sidewall height of 4.22 inches.  
         [0035]    Preferably, the pressure of the inner tire  10  is maintained at a higher value than the inflation pressure of the outer tire. In this manner, should there be a loss of pressure by the outer tire, the pressurized inner tire provides an internal support for the outer tire so that the vehicle may be controlled and brought to a safe stop.  
         [0036]    Although preferred embodiments of the invention have been described using specific terms, devices, and methods, such description is for illustrative purposes only. The words used are words of description rather than of limitation. It is to be understood that changes and variations may be made by those of ordinary skill in the art without departing from the spirit or the scope of the present invention, which is set forth in the following claims. In addition, it should be understood that aspects of the various embodiments may be interchanged, both in whole or in part. Therefore, the spirit and scope of the appended claims should not be limited to the description of the preferred versions contained therein