Abstract:
An improved method of shipping and storing tires having a removable tread belt mounted to a tire carcass which are typically used on large vehicles such as earthmovers. The method includes shipping the tread belt separately from the tire carcass; and holding two opposite sides of the tread belt in mating engagement during shipping.

Description:
TECHNICAL FIELD OF THE INVENTION 
   This invention relates to a method for shipping and storing removable tread belts for use with very large pneumatic tires typically for use with very large vehicles such as earthmoving vehicles. 
   BACKGROUND OF THE INVENTION 
   Removable tread belt pneumatic tires, which are the subject of the method of the present invention, are typically very large tires having a 10 foot outside diameter (OD). These very large tires are designed for use on very large vehicles, generally off-the-road (OTR) vehicles such as earthmovers and large-capacity mining trucks (e.g., 300 short tons or more). As modem construction vehicles have evolved to larger and larger sizes, their tires have also grown to the point where conventional shipping of the tires becomes difficult. For example, an existing design of a 360-ton truck requires pneumatic tires having a 150 to 154 inch diameter, which is considered to be the maximum size tire reasonably possible to ship by conventional means in the United States. Tire weight is another consideration, as very large tires can weigh 8,000 to 15,000 pounds or more per un-mounted tire. 
   When pneumatic tires become so large that they cannot be shipped by conventional means, one solution to this problem is to utilize a two piece tire wherein the tire tread belt is removable from the tire carcass. For example, see U.S. Pat. No. 6,357,498 entitled TIRE WITH REMOVEABLE TIRE TREAD BELT AND IMPROVED APEX DESIGN, having a common assignee with the present invention, which discloses a tire having an improved removable tire tread belt for use on large earthmover vehicles. The use of a two piece tire design produces significant weight and size reductions, thereby allowing the use of conventional shipping means. 
   Thus, there is still a need for an improved method of shipping very large tires that allows for the employment of more conventional shipping means, and that reduces the work site storage requirements as well. 
   SUMMARY OF THE INVENTION 
   According to a first aspect of the invention, a spacer is provided for the compressed tread belt forming the tread belt into an elongated straight-sided oval shape. 
   According to another aspect of the invention, the tire carcass may also be held in a compressed state for shipping. 
   Other objects, features and advantages of the invention will become apparent in light of the following description thereof. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The structure, operation, and advantages of the present preferred embodiment of the invention will become further apparent upon consideration of the following description taken in conjunction with the accompanying drawings, wherein: 
       FIG. 1  is a cross-sectional view illustrating half of a removable tread belt pneumatic tire; and 
       FIG. 2  is a side view of a tread belt prepared for shipping, according to the invention. 
   

   DEFINITIONS 
   “Bead” means that part of the tire comprising an annular tensile member wrapped by the ply cords and shaped, with or without other reinforcement elements such as flippers, chippers, apexes, toe guards and chafers, to fit the wheel rim. 
   “Belt or breaker reinforcing structure” means at least two layers of plies of parallel cords, woven or unwoven, underlying the tread, unanchored to the bead, and having both left and right cord angles in the range from 17 degrees to 33 degrees with respect to the equatorial plane of the tire. 
   “Bias ply tire” means a tire having a carcass with reinforcing cords in the carcass ply extending diagonally across the tire from bead core to bead core at about 25°–50° angle with respect to the equatorial plane of the tire. Cords run at opposite angles in alternate layers. 
   “Circumferential” means lines or directions extending along the perimeter of the surface of the annular tread perpendicular to the axial direction. 
   “Cord” means one of the reinforcement strands of which the plies in the tire are comprised. 
   “Equatorial plane (EP)” means the plane perpendicular to the tire&#39;s axis of rotation and passing through the center of its tread. 
   “Footprint” means the contact patch or area of contact of the tire tread with a flat surface under load and pressure. 
   “Lateral” and “laterally” means lines or directions that are parallel to the axis of rotation of the tire (also “axial”). 
   “Normal inflation pressure” refers to the specific design inflation pressure at a specific load assigned by the appropriate standards organization for the service condition for the tire. 
   “Normal load” refers to the specific load at a specific design inflation pressure assigned by the appropriate standards organization for the service condition for the tire. 
   “Ply” means a continuous layer of rubber-coated parallel cords. 
   “Radial and “radially” means directions extending radially toward or away from the axis of rotation of the tire. 
   “Radial-ply tire” means a belted or circumferentially-restricted pneumatic tire in which the ply cords which extend from bead to bead are laid at cord angles between 65 degrees and 90 degrees with respect to the equatorial plane of the tire. 
   “Zero-degree wires” means at least one layer of parallel cords (usually metal wire), underlying the tread, unanchored to the bead, spiraling circumferentially around the tread, and having cord angles in the range from 0 degrees to 5 degrees with respect to the equatorial plane of the tire. 
   DETAILED DESCRIPTION OF THE INVENTION 
   The method of this invention utilizes a tread belt version of a very large tire, such as tires greater than 10 feet in diameter as used on earthmover-type very large vehicles. The method is not dependent on a particular design for the removable tread belt and carcass. Although a specific very large tire design is described hereinbelow for illustrating the embodiment of this inventive method, the inventive method should not be limited to this particular tire design. 
     FIG. 1  illustrates a cross-section of a portion of a very large tread belt pneumatic tire  10  which in the specific embodiment illustrated is a size 70/68R63 earthmover tire. The size 70/68R63 tire has a 162-inch maximum inflated outside diameter (OD), a 70.0-inch maximum inflated width in the axial direction, and a nominal bead diameter of 63 inches. The tread belt  12  has a thickness (t) of approximately 10 inches (254 cm), and a width of approximately 65 inches (1,651 cm). The assembled tire  10  weighs 16,000 pounds (7,256 kg), of which approximately 8,000 pounds (3,628 kg) are in the removable tread belt  12 . The tire carcass  14  is typically inflated to a pressure of about 100 pounds per square inch (686 kPa) with air and sometimes with an air/nitrogen mixture. The very large tread belt pneumatic tire  10  includes a ground engaging, circumferentially extending tread belt  12  mounted on a radially reinforced, beaded tire carcass  14 . The beaded tire carcass  14  generally includes a pair of tire sidewalls  16  extending radially inwardly from the outer circumferential surface  20  of the tire carcass  14  and terminating at a pair of bead wires  22 . The sidewalls  16  each have an upper portion  16   a  in the shoulder region of tire carcass  14  and radially outward of the maximum section width of the tire carcass  14 , and a lower portion  16   b , adjacent the bead wires  22 , and radially inward of the maximum section width of the tire carcass  14 . 
   Most details of the tire carcass  14  construction are not relevant to the method of this invention, and will not be described other than to note that the carcass  14  generally contains at least one rubberized laminated ply layer  34  of tire cord fabric. The carcass  14  mounts on the wheel mounting rim  42 , pneumatically sealing in the area of the bead  22  against, and held in place by, the flange  35 , which is generally removable from the rim  42  on wheels used for very large tires  10 . 
   An optional feature is generally included in removable tread belt tires  10  in order to assist in holding the removable tread belt  12  in place on the carcass  14 . This optional feature, illustrated in  FIG. 1 , comprises a set of one or more grooves  78  and one or more lands  76  formed in the outer circumferential surface  20  of the carcass  14 . 
   The ground engaging, circumferentially extending tread belt  12  is removably mounted onto the tire carcass  14 . At a minimum, the tire tread belt  12  comprises a tread portion  80 , and at least one belt  82 ,  84 ,  86 , and/or  88  ( 82 – 88 ) or set of zero-degree wires  90  which encircle the tire tread and are provided to restrict the radially outward growth of the tread belt  12 . It is preferred that the one or more belts have low circumferential hoop stiffness (increased flexibility) obtained when a majority of the reinforcement belt angles are high, i.e. greater than 22 degrees. The placement and shape of the wires  90  and/or the belts  82 – 86  are the subject of other patents, and are not critical to the method of this invention. 
   An optional feature of the tread belt  12  embodiment illustrated in  FIG. 1  comprises one or more annular lands  72  and one or more annular grooves  74  in the underside or inner circumferential surface  70  of the tread belt  12  that interlock with corresponding grooves  78  and lands  76  of the tire carcass  14  to restrain the tread belt  12  from lateral or axial movement with respect to the carcass  14 . 
   Until the recent advent of increasingly larger “very large” pneumatic tires, there was very little perceived need for removable tread belt versions of these tires. The present invention has identified a new category of problems related to the very large tires, and provides methods for shipping, storing, and changing of very large tires which utilize removable tread belt tire designs to address the shipping, storing, and changing problems which are unique to these tires. 
   Method of Shipping Very Large Tires 
   When pneumatic tires become so large that they cannot be shipped by conventional means, the shipping method of this invention is to utilize removable tread belt tires (e.g.,  10 ), and to ship the tire tread belt  12  separately from the tire carcass  14 . Regardless of how they are prepared for shipping, the action by itself of separating the tread belt  12  from the carcass  14  produces significant shipping weight and size reductions. For the example illustrated in  FIG. 1 , the overall tire diameter decreases from a whole tire OD of approximately 162 inches to approximately 142 inches for the outside diameter of the tire carcass  14 . Likewise, the weight of 16,000 pounds for the whole tire is separated into an approximately 8,000 pound carcass  14  and an approximately 8.000 pound tread belt  12 . 
   The separate tread belt  12  can be compressed into various smaller dimensions when prepared for shipping. A preferred embodiment 200 is illustrated in  FIG. 2 , wherein the tread belt  12  is diametrically compressed and held in the compressed state by one or more straps  210  ( 210   a ,  210   b ) made of steel or other suitable shipping strap material such as plastic, fabric, rope, or chains. To prevent collapse of the tread belt  12  and potential damage of the belt due to overly sharp bending of the ends  212   a  and  212   b , one or more spacers  220  are positioned at each respective end  212   a , 212   b  inside the tread belt  12 . The straps  210   a ,  210   b  hold the tread belt  12  compressed against an opposite side of the belt. The spacer  220  is preferably circular in cross-sectional shape, and is constructed by known techniques and using materials suitable to support the weight and shipping forces of the tread belt  12  during shipping. For example, wood or metal constructions, or plastic pre-forms could be used, providing the spacer does not have any sharp edges which could damage a surface of the tread belt  12 . The dimensions of the spacer are such as will maintain support of the tread belt  12 , typically on the order of about twenty-four (24) inches in diameter, depending upon the belt size. 
   Since tread belts  12  consume much less storage space than carcasses  14 , the use of removable tread belt tire designs for very large tires presents significant advantages in storage. These advantages carry over into inventory cost savings and shipping cost savings as well, since tread belts  12  are less costly to both purchase and ship compared to carcasses  14  and to conventional very large tires. 
   Although the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only preferred embodiments have been shown and described, and that all changes and modifications that come within the spirit of the invention are desired to be protected. Undoubtedly, many other “variations” on the “themes” set forth hereinabove will occur to one having ordinary skill in the art to which the present invention most nearly pertains, and such variations are intended to be within the scope of the invention, as disclosed herein.