This invention relates to methods for changing very large pneumatic tires typically used on very large vehicles such as earthmoving vehicles and, more particularly, to methods enabled by the use of a removable tread belt pneumatic tire construction.
In U.S. Pat. No. 6,526,659, a method of changing very large tires is disclosed. In that patent it is noted that tread belt pneumatic tires which are subject to the method of the present invention are very large tires (greater than 119.9 inches outside diameter (OD)) generally designed for use on very large vehicles, generally off-the-road vehicles such as earthmovers and large capacity mining trucks (e.g., 300 short tons or more). The size of these tires is extremely large. For an example, the tire weight can be approximately 8,000 pounds (3,628 kg) to 15,000 pounds (6,803 kg) or more for an unmounted tire. When using a two-piece type tire wherein the tread belt forms the outer structure and the inner structure is formed by a carcass wherein the two parts are separable, the tread belt alone will weigh over 4,000 pounds typically, many times more depending on the size. By way of example, a 57 inch nominal rim diameter two-piece tire having a 45R57 size will have a tread belt assembly having an outside diameter of approximately 12 foot or roughly 144 inches and will weigh approximately a little more than 4,500 pounds, a smaller but still very large 51 inch nominal rim diameter tire of a 3300R51 size yields a 3000 lb. tread belt, and the massive 63 inch 59R63 tire has a tread belt weighing in at 8424 lbs. In order to change a worn tread belt assembly on a preexisting carcass or even to apply one onto the carcass, it has been determined that it is more efficient to change the tread belt assembly while the carcass is mounted on the rim and attached to the vehicle.
In the prior art U.S. Pat. No. 6,526,659 to Rayman, it was disclosed that the tire could be deflated and the old or worn tread belt could be pulled off the deflated carcass and then the new tread belt assembly could be driven onto by the deflated carcass and pushed onto the tire by spinning the wheel. Effectively, the invention suggested that the partially deflated carcass could drive out of the old tread belt and be driven into the replacement tread belt, respectively, in order to accomplish the tread belt changeover. In practice, while this invention seems to provide a rather simplified method of assembly, it has been determined to be much more difficult when put into practice. Such a method runs the risk of having the large tread belt assembly fall which could cause catastrophic injury to the personnel trying to accomplish the tread belt changeover and the movement of the vehicle on the deflated carcass is considered to be somewhat risky and unacceptable.
What was considered important in this prior art method of tread belt changeover is that by not removing the rim assembly and carcass from the vehicle significant amount of time can be saved when replacing a tread belt assembly. A second consideration of the prior art invention was that while it worked for the outside axle wheels it is basically impractical for the interior wheel on a dual axle in that there is no way that the tread belt can be positioned over both carcasses. Accordingly, assuming you have a dual wheel position axle as is typically the case in these large earthmover tires, an improved method was required in order to access the interior axle wheel and to accomplish a tread belt changeover.
An object of the present invention is to accomplish a replacement of a tread belt assembly onto a carcass mounted on a vehicle rim already mounted to the vehicle. It is a further object of the present invention to accomplish a removal of a worn tread belt while mounted to a carcass mounted onto a vehicle and to achieve this removal of the tread belt whether on an inside axle position or an outboard axle position on a dual wheel assembly. Other objects and features and advantages of this invention will become apparent in light of the following description.
A method of forming a two-piece tire assembly by mounting a giant tread belt onto a tire carcass when the carcass is mounted on a rim which is also mounted on a vehicle is disclosed. The method has the steps of jacking the vehicle wheel position up so that the wheel clears the ground; pulling a vacuum partially collapsing the carcass; placing a vertical upper radially inner portion of the tread belt onto a top surface of the carcass about one-half way or more across the axial width of the carcass, thereby supporting the tread belt weight; pushing the rest of the tread belt radially over the carcass a predetermined distance; inflating the carcass to a predetermined pressure to form the two-piece tire assembly while mounted on the vehicle.
In normal practice, the method will further include the step of deflating the carcass and removing the existing tread belt assembly from the carcass prior to installing the new tread belt. In the preferred embodiment, this method includes inserting a pair of support arms in the tread grooves of the tread belt to engage the radially outer surface of the tread belt. After the support arms are engaged, the operator pulls the tread belt using the support arms to remove the tread belt from the deflated and vacuumed carcass. Preferably the support arms are tilted angularly to lift the tread belt as it is pulled from the carcass.
The radially inner surface of the tread belt and the radially outer surface of the carcass may include interlocking circumferentially continuous ribs and grooves. The preferred method may further have the step of aligning these interlocking grooves and ribs prior to inflating the carcass. The preferred method of mounting the new tread belt assembly preferably includes the step of using the support arms inserted a distance not more than the full width of the tread belt preferably substantially less than the full width of the tread belt and then moving the tread belt over the carcass past the support arms. This enables the tread belt to be placed on the upper half of the carcass without having the support arms impacting the carcass. Preferably, the steps of holding includes the step of tilting the support arms and tread belt such that as the tread belt approaches the carcass, it is brought to the carcass on an angle. As the support arms push the tread belt onto the carcass, the weight of the tread belt will move the lower position of the tread belt at least partially over the carcass as a function of gravity. The preferred method further includes the step of lifting or optionally pushing the tread belt using the support arms to position the tread belt over the carcass. The manipulating support arms preferably are capable of angular rotation such that the support arms can locally lift or push the tread belt onto the carcass in any circumferential direction.
Generally, the rims of these large tires include a removable rim flange and sealing means. It is preferred that the step of mounting a two-piece tire assembly further includes the step of clamping the separate rim flange to the rim prior to pulling a vacuum. This ensures that the beads and rim flange remain fully seated and a seal can be effected. Otherwise, the rim flange may move preventing a vacuum to be pulled on the carcass.
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 design 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° to 75° 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.
“Carcass” means a radial or bias tire structure absent the tread and belt structure.
“Casing” means a radial or underlying tire structure absent the tread.
“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” mean 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” mean directions extending radially toward or away from the axis of rotation of the tire.
“Radial-ply tire” means a pneumatic tire in which the ply cords, which extend from bead to bead are laid at cord angles between 65° and 90° 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.
Reference will be made in detail to the preferred embodiments of the invention, examples of which are illustrated in the accompanying drawing figures. The figures are intended to be illustrative and not limiting. Although the invention is generally described in the context of these preferred embodiments, it should be understood that it is not intended to limit the spirit and scope of the invention to these particular illustrated embodiments.
Certain elements in selected views of the drawings may be illustrated for clarity. Cross-sectional views, if any presented herein, may be in the form of slices or near-sided cross-sectional views omitting certain background lines which would otherwise be visible in a true cross-sectional view, for illustrative clarity.
The method of this invention requires a tread belt version of a very large tire (such as tires 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 except for a two piece tire with removable tread belts generally.
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 62, 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
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 a layer 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 illustrated in
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 of changing very large tires which utilize removable tread belt tire designs to address the handling and changing problems which are unique to these tires.
With reference to
As shown, the flange clamping means 36 preferably is four pieces 37, 38. Preferably three block portions 37 interlock with the bead seat band 33 and abuts against a portion of a secondary clamp ring portion 38 as shown. The secondary clamp ring portion 38 is used that presses against the first clamp block portion 37 and the rim cylindrical base 32. As illustrated, a threaded fastener 39 is inserted through the secondary clamping ring 38 and threaded into each of the blocks 37 which pulls the bead seat band 33 firmly against the bead locking ring 34. When this is accomplished, the entire assembly remains in the locked position as illustrated. The locking ring 34 holding the bead seat band 33, the flange 35 and the rim base 32 together is shown between the bead seat band 33 and the clamping blocks 37 and clamping ring 38 as illustrated. This simple clamping mechanism can be placed in approximately two to three locations around the rim flange 35 and this plurality of flange clamping means 36 will ensure that the rim flange 35 will not move.
Method of Changing Very Large Tires
Utilizing very large removable tread belt tires 10 for the very large vehicles at a work site, according to the method of this invention, makes the process of changing tires significantly more cost effective. When conventional very large tires are used, a first tire on a wheel must be removed from the very large vehicle, the first tire must then be removed from the wheel and replaced with a second tire, and then the second tire on the wheel must be replaced on the very large vehicle 600. This tire changing process typically requires as much as 5 to 6 hours for a single tire change.
In the embodiment 500 of the very large tire changing method of this invention, the tire 510 having a first tread belt 512a which is to be changed must be positioned so that the first tread belt 512a is removed from contact with a load bearing surface such as the ground. In this example, an appropriate portion 525 of the very large vehicle 600 is raised on a jack 549 (e.g., a pneumatic jack). Next, the tire carcass 514 holding the first tread belt 512a to be changed is deflated by removing the air or air/nitrogen and a vacuum is pulled until the first tread belt 512a becomes loose about the tire carcass 514. Next, the first tread belt 512a is laterally removed from the tire carcass 514 using the device described below.
As illustrated in
The replacement second tread belt 512b can now be laterally moved onto the tire carcass 514 as shown in
Finally, the tire carcass 514 is preferably inflated to its proper inflation pressure, and is inflated at least enough to cause the second tread belt 512b inner circumferential surface 70 to conform closely to the outer circumferential surface 20 of the tire carcass 514. The very large tire change is complete, and the very large vehicle 600 can be placed back in service by lowering it to the ground 537, such as by lowering and removing the pneumatic jack 549.
Due to the relative ease of the inventive methods of storing and changing tread belts 12 for very large tires 10, this invention makes it feasible to change tread belts 512 to utilize different tread designs to accommodate different operating conditions such as different load-bearing surface conditions (e.g., as caused by changes in environmental conditions: wet/dry, summer/winter, mud/snow/dry), or such as different applications of the very large vehicles 525 (e.g., usage on gravel, dirt, sand, rough terrain or paved roadway, high speed driving, low speed driving).
With reference to
As further illustrated, the manipulator mechanism 530 is mounted on an angular rotating plate 536 such that the operator can rotate the entire manipulator 530 approximately 180° in either direction. This is important, as discussed, once the tread belt 512b is placed onto the carcass 514, the manipulator 530 can be used to lift or push the tread belt 512b onto the carcass 514 or, alternatively, it can be rotated to assist in pulling a tread belt 512a off of a carcass and can maneuvered while inserted between the tread belt 512a and the carcass 514 or simply in the grooves of the tread or it can be maneuvered when simply lifting or pushing a tread belt 512b onto a carcass 514. As illustrated in
As shown, the manipulator arms 531 have a significantly large amount of reach length and space and can therefore traverse across and actually over an outer two piece tire assembly and can reach inward to the inward mounted two piece tire assembly in a dual wheel position. In such a case by removing the first tread belt assembly 512a from the first tire carcass 514 using the procedure as previously outlined it is possible to then remove the internal or inboard mounted tread belt assembly 512a from the carcass 514 by reaching over the first carcass 514 and inserting the support arms between the tread belt 512a and the inner carcass 514 or into the grooves on the tread's outer surface after a vacuum has been pulled and removing the tread belt 512a off the inboard carcass 514 and actually pulling it over the outboard carcass 514. In this way, tread belt assemblies 512a can be removed from both wheel positions. Furthermore, the entire process can be repeated wherein the new replacement tread belt assembly 512b is actually positioned over the first carcass 514, passing over the first carcass 514 and can reach to insert the tread belt 512 onto the inboard tread carcass 514. Absent these manipulator support arms 533a, 533b, it is not fully possible to simply pull a worn tread belt 512a or place a new tread belt 512b over a pair of carcasses due to the fact that the weight must be secured. The fact that the manipulator support arms 533 can be used to maneuver across both tire carcass assemblies 514 by spanning and reaching over and pulling the worn tread belts permits removal and replacement of both wheel positions in a dual wheel assembly. Such tread belt to carcass assembly technique is feasible using the present invention.
The manipulation of the mechanism 530 is controlled using the hydraulic controls of the lift truck not illustrated. Hydraulic fluid lines 580 are shown which directly transmit commands for motion to the various support arms 533 to change angles and orientation.
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 here,
Number | Date | Country | |
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Parent | 10625346 | Jul 2003 | US |
Child | 11603740 | Nov 2006 | US |