Method of shipping storing and changing very large tires

Abstract: Method of shipping, storing, and changing very large tires (10) having a removable tread belt (12) mounted to a tire carcass (14) which are typically used on very large vehicles (525) such as earthmovers. By compressing both the tread belts and the tire carcasses, they can be shipped separately so that less shipping and storage space is required. Tire changing only requires changing the tire tread without removing the wheel or carcass from the very large vehicle making it economically feasible to store and change tread designs to accommodate a variety of very large tire/vehicle operating conditions.

Description: TECHNICAL FIELD OF THE INVENTION This invention relates to methods for shipping, very large pneumatic tires typically for use with very large vehicles such as earthmoving vehicles, and more particularly to the methods enabled by the use of a removable tread belt pneumatic tire construction. BACKGROUND OF THE INVENTION The tread belt pneumatic tires which are the subject of the method of the present invention are very large tires (greater than 120 inch (3.05 meter) outside diameter (OD)) generally 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). These very large tires and vehicles are generally utilized at long-term mining or construction sites such as rock quarries, mines, foundries, major tunnel/roadway construction, dams/dikes, and the like. The very large vehicles are generally too large to transport to the work site normally, and are therefore often shipped in pieces to the work site where the pieces are assembled/welded together for use. As modern 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 360 ton (32,6530 kg) truck requires pneumatic tires of 150 to 154 inch diameter (3.91 meter) which is considered to be the maximum size tire reasonably possible to ship by conventional rail or roadway means in the United States. Tire weight is another consideration, as very large tires can weigh 8,000 pounds (3,628 kg) to 15,000 pounds (6,803 kg) or more per un-mounted tire. The industry would like to progress to even larger, 400 ton (362,812 kg) or 450 ton (408,163 kg) trucks with correspondingly larger tires of 160 inch (4.07 meter) diameters or more. Depending on local limitations of shipping means (such as tunnel/bridge clearances and roadway weight limits), even somewhat smaller ones of the "very large tires" may pose significant problems, and may therefore require extraordinary transport means such as by helicopter. Another problem faced by the users of very large pneumatic tires is changing the very large tires on the very large vehicles. The very large vehicles are generally employed in areas such as rock quarries, where the tires are subjected to high stress and loads, usually under harsh environmental conditions wherein tires are subjected to puncture-producing and wear-inducing conditions. Under these conditions, tires are damaged relatively frequently and must be changed at the work site. Even with removable-flange wheels, changing very large tires is a difficult and time-consuming process, requiring as much as 5 to 6 hours for a single tire change. Another problem is storage of the very large tires at the work site. As tires become larger, more and more space is required for storage. Also, if operating conditions are particularly harsh, or if shipping of replacement tires "on demand" is not practical, then increased numbers of spares must be stocked, further increasing the storage space needed. Furthermore, some job sites require different tread designs for different operating conditions. For example, wide treads with deep cleats may be needed for muddy conditions such as in rainy weather, versus normal- width treads with a different cleat design for operation on gravel or in dry weather conditions. Given the time consuming nature of the existing tire-changing methods, changing tires to obtain optimum tread patterns is not always feasible. Finally, even if driving tires and steering tires on the very large vehicles are the same overall size, the tread patterns of the two types of tires need to be different for most effective operation. This again adds to the number of replacement tires which must be stored at a work site. There is therefore a need for a method of shipping very large tires that allows for the employment of more conventional shipping means, and there is a desire to reduce the work site storage requirements as well as to improve the efficiency of the very large tire changing process. Although tires having replaceable treads are known in automotive/motorcycle and conventional truck tire applications, it is not until recently that tread belt tires have been developed to meet the unique requirements of very large pneumatic tires for very large vehicles. U.S. Patent Application No. 09/424,089 entitled TIRE WITH IMPROVED REMOVABLE TIRE TREAD BELT to Rayman, having a common assignee with the present invention, of which this invention is a continuation in part, discloses a tire with an improved removable tire tread belt for use on large earthmover vehicles. This tread belt tire (also called a "track belt tire") "is constructed of a removable tread belt assembly mounted to the outer circumferential surface of an inflatable tire carcass. A unique track belt design restrains the track from expanding while simultaneously improving the secure mounting of the track to the carcass and providing improved penetration protection. Also, the improved track belt will maintain a flatter tread profile which in turn will improve tread life and durability." A predecessor version of removable treads or tracks for very large tires is discussed in US-A- 4,351,380, wherein certain prior art track belt tire assemblies comprise a plurality of ground-engaging "shoes" spaced about the periphery of the supporting structure. The heavy loads on the "shoes" result in great stresses being developed that sometimes lead to premature tire failure. US-A- 4,351,380 patent is directed to an improved track belt assembly which comprises a plurality of shoes spaced about the periphery of a load-supporting structure and secured to a reinforcing belt structure disposed on the side of the shoe opposite the ground-engaging side thereof. A body of prior art exists for tires with removable tread belts (see, for example, US-A- 3,897,814; 3,224,482; 3,087,526 and GB-A- 2,073,109). However these patents were directed toward the addressing of various issues related to tires used by predominantly roadway vehicles such as automobiles and trucks. Examples of these issues include: varying cord spacing to reduce wear of the outer tread belt edge for "enhanced service life and lower manufacturing cost"; improving transverse bending for "better riding comfort and improved road holding ability"; and linking separate tread rings to improve "road-holding capabilities and... silent riding." Accordingly, the prior art has varied the quantity, shape, placement and spacing of tread rings, reinforcing belts, inextensible cords, and interlocking grooves in the tire carcass and tread belt, but these variations have not been adequate to address the special needs of off-the-road vehicle tires, nor of very large tires in general. There are still unsolved problems, relating to a pneumatic tire and tread belt assembly, concerning shipping, storage, inventory, and changing of very large tires on very large vehicles. SUMMARY OF THE INVENTION The present invention relates to an improved method for shipping, very large pneumatic tires which are used on very large vehicles such as earthmover vehicles. Very large tires of conventional construction are sometimes over 13 feet (4 meters) in height and approximately 8,000 pounds (3,628 kg) to 15,000 pounds (6,803 kg) in weight, and proposed very large truck designs require even larger tires. The size and weight of the very large conventional tires presents significant problems in shipping, storage and tire changing. According to the invention, the very large tires are removable tread belt tires and the tread belt is shipped separately from the tire carcass. The removable tread belt is held in a compressed state for shipping, thereby having a significantly-reduced diameter for ease of shipping. According to an 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. BRIEF DESCRIPTION OF THE DRAWINGS Reference will be made in detail to preferred embodiments of the invention, examples of which are illustrated in the accompanying drawing figures. The figures are intended to be illustrative, not limiting. Certain elements in selected ones of the drawings may be illustrated not-to-scale, for illustrative clarity. The cross-sectional views, if any, presented herein may be in the form of "slices", or "near-sighted" cross-sectional views, omitting certain background lines which would otherwise be visible in a true cross-sectional view, for illustrative clarity. Elements of the figures are typically numbered as follows. The most significant digits (hundreds) of the reference number corresponds to the figure number. Elements of Figure 1 are typically numbered in the range of 100-199. Elements of Figure 2 are typically numbered in the range of 200-299. Similar elements throughout the drawings may be referred to by similar reference numerals. For example, the element 199 in a figure may be similar, and possibly identical to the element 299 in an other figure. In some cases, similar (including identical) elements may be referred to with similar numbers in a single drawing. For example, each of a plurality of elements 199 may be referred to individually as 199a, 199b, 199c, etc. Such relationships, if any, between similar elements in the same or different figures will become apparent throughout the specification, including, if applicable, in the claims. 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: Figure 1 is a cross-sectional view illustrating half of a portion of a removable tread belt tire, according to the invention; Figure 2A is a side view of a tread belt prepared for shipping, according to the invention; Figure 2B is a side view of an alternative embodiment of a tread belt prepared for shipping, according to the invention; Figure 3A is a side view of a tire carcass optionally prepared for shipping, according to the invention; Figure 3B is a cross-sectional view of a tire carcass optionally 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'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 requires a tread belt version of a very large tire (such as tires greater than 120 inches (3.05 meters) 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 matching 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. Figure 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 (411.45 cm) maximum inflated outside diameter (OD), a 70.0 inch (177.80 cm) maximum inflated width in the axial direction, and a nominal bead diameter of 63 inches (160.02 cm). 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 16a 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 16b, 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 Figure 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. 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 Figure 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, of very large tires which utilize removable tread belt tire designs to address the shipping, 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 Figure 1, the overall tire diameter decreases from a whole tire OD of approximately 162 inches (4.11 meters) to approximately 142 inches (3.61 meters) for the outside diameter of the tire carcass 14. Likewise, the weight of 16,000 pounds (7,256 kg) for the whole tire is separated into an approximately 8,000 pound (3,268 kg) carcass 14 and an approximately 8.000 pound (3,268 kg). The separate tread belt 12 can be compressed into various smaller dimensions when prepared for shipping. A preferred embodiment 200 is illustrated in Figure 2A, wherein the tread belt 12 is diametrically compressed and held in the compressed state by one or more straps 210 (210a, 210b, 210c, 210d, 210e) 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 212a and 212b, a spacer 220 is positioned inside the tread belt 12. The straps 210 hold the tread belt 12 compressed against diametrically-opposed sides of the spacer 220, and the spacer 220 is constructed so that the compressed shape of the tread belt 12 is preferably an elongated straight-sided oval with a height (H) to length (L) ratio of no less than 40%. This H/L ratio minimum is intended to prevent damage of the belt due to overly sharp bending of the ends 212a and 212b of the tread belt 12. The spacer 220 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 over approximately 40% to 70% of the compressed length L, over a minimum of 50% of the tread belt width W, and will also provide the minimum H/L ratio stated above. For convenience in handling, the compressed tread belt 12 is preferably strapped onto a bottom pallet 230 of dimensions suitable to support at least the entire width W and at least the flat-sided length Lf of the compressed tread belt 12. The pallet 230 is constructed by known techniques and of suitable, known pallet materials, and is designed to be able to sustain expected weights and shipping forces. A top pallet 232, similar to the bottom pallet 230, is optionally added above the compressed tread belt 12 and held in place by the straps 210. By using two pallets 230, 232 with the straps 210 encircling below the bottom pallet 230 and above the top pallet 232, the tread belt 12 is protected from damage by contact with the straps 210. Figure 2B illustrates an alternative embodiment 250 of a very large tire tread belt 12 prepared for shipment in a compressed state. This alternative embodiment 250 maintains the same shape and overall compressed tread belt dimensions as the preferred embodiment 200, but the tread belt 12 has been placed on its side. Although a spacer 270 is still utilized inside the tread belt 12 in order to maintain the same minimum H/L ratio for the tread belt 12, the spacer 270 may be constructed with a lower strength since it is no longer bearing the weight of approximately half of a tread belt 12 above (or even more if the compressed tread belts are to be stacked). The bottom pallet 280 has a width Wp greater than or approximately equal to the height H of the compressed tread belt 12, and a length Lp which is at least the flat-sided length Lf but preferably equals the compressed length L of the compressed tread belt 12. One or more straps 260 (260a, 260b, 260c) encircle the tread belt 12 and the bottom pallet 280 to hold the tread belt 12 in a compressed state about the spacer 270. A top pallet 282, similar to the bottom pallet 280, is optionally added above the compressed tread belt 12 and held in place by the straps 260. By using two pallets 280, 282 with the straps 260 encircling below the bottom pallet 280 and above the top pallet 282, the tread belt 12 is protected from damage by contact with the straps 260. Figures 3A and 3B illustrate an optional shipping method 300 for the very large tire carcass 14. This method is optional because the overall tire OD is significantly reduced by utilization of a removable tread belt design 10 for the very large tire according to the method of this invention. Furthermore, the amount of diametrical compression possible for a tire 10 or a tire carcass 14 is severely limited by the rigidity of the carcass sidewalls 16 and beads 22. However, if the very large tire 10 is so large that even the reduced diameter of the tire carcass 14 presents problems in shipping, then the diameter of the tire carcass 14 can be somewhat further reduced by compressing it with straps 310 (310a, 310b) which are applied across a diameter of the tire carcass. As for the tread belt straps 210, 260, the straps 310 may be made of any suitable material such as steel, plastic, fabric, rope or chains. If the choice of material for the straps is considered unduly abrasive or sharp-edged, then suitable padding should be provided between the straps 310 and the tire carcass 14. Best seen in the cross-sectional view of Figure 3B, optional end-caps 315 may be placed between the straps 310 and the tire carcass 14. The end-caps 315 are plywood or other suitably rigid rectangular elements made of wood, plastic or metal which have a length Lc approximately equal to the flat-sided length of the compressed tire carcass 14 and a width Wc which equals or slightly exceeds the width of bulged-out sidewalls 316 (316a, 316b, 316c, 316d). Since the bead wires 22 are significantly more rigidly circular than the remainder of the tire carcass 14, when the straps 310 compress the tire carcass 14 the sidewalls 316 will tend to wrinkle, and it is preferable to allow them to bulge laterally outward relative to the tire's equatorial plane. An outward bulge is the natural direction for tire sidewall movement, and as such produces the least strain on the elements of the tire carcass 14. The end-caps 315 hold the straps 310 laterally outward away from the sidewalls 316, thereby allowing the sidewalls 316 to bulge in their most natural way in response to the diametrical compression forces exerted by the straps 310. The dimensions (Lc by Wc) of the endcaps 315, are determined empirically as they are dependent on the individual tire carcass 14 and its response to the amount of compression forces applied by the straps 310 as the straps 310 compress the tire carcass 14 to the desired shipping diameter Dc. The shipping methods described hereinabove have been illustrated by embodiments 200, 250, 300 which incorporate straps 210, 260, 310 to hold the tread belts 12 and tire carcasses 14 in compressed states. Given the shipping methods herein described, a person skilled in the art may see alternative means of holding the tread belts 12 and tire carcasses 14 in compressed states, such as the use of a restraining box-like structure around some or all portions of one or more tread belts 12, or a restraining box-like structure around some or all portions of one or more tire carcasses 14.

Claims: Method of shipping very large pneumatic tires (10), having diameters (OD) over 120 inches (3.05 meters), wherein the very large tire comprises an inflatable tire carcass (14) and a removable tread belt (12) surrounding the tire carcass and conforming to the tire carcass when the tire carcass is inflated; the method characterized by the steps of: shipping the tread belt separately from the tire carcass; and holding two diametrically opposite sides of the tread belt in a compressed state (200, 250) during shipping, thereby reducing a distance (H) between the two diametrically opposite sides of the tread belt. Method of claim 1 characterized by the step of: placing a spacer (220, 270) inside the tread belt (12); and strapping (210, 260) the tread belt so that the two diametrically opposite sides of the tread belt are held against the spacer, forming the tread belt into an elongated straight-sided oval in its compressed state. Method of claim 1 characterized by the step of holding two diametrically opposite sides of the tire carcass (14) in a compressed state (300) during shipping thereby reducing a distance (Dc) between the two diametrically opposite sides of the tire carcass.

Inventors: RAYMAN WILLIAM EARL, RAYMAN, WILLIAM EARL
Applicants: GOODYEAR TIRE & RUBBER, THE GOODYEAR TIRE & RUBBER COMPANY
Application year: 2001
Main classification: B65D85
IPC codes: B65D71, B60C25, B60C19, B65D85, B60C11