WO2015116181A1

WO2015116181A1 - Methods of forming a retreaded tire

Info

Publication number: WO2015116181A1
Application number: PCT/US2014/014204
Authority: WO
Inventors: Metodi L Ikonomov; David Chan Wah LUNG; Adib T. Chebli
Original assignee: Compagnie Generale Des Etablissements Michelin; Michelin Recherche Et Technique S.A.
Priority date: 2014-01-31
Filing date: 2014-01-31
Publication date: 2015-08-06

Abstract

Methods of forming a retreaded tire, and retreaded tires formed thereby include providing an unbonded retreaded tire and forming a curing assembly having an inner chamber arranged along the inner side of the unbonded retreaded tire containing an inflatable bladder for applying forces against the inner side of the unbonded retreaded tire. Furthermore, a flexible curing membrane sized for use with a plurality of differently sized unbonded retreaded tires is arranged around an outer circumference of the unbonded retreaded tire to form a vacuum chamber along an outer side of the unbonded retreaded tire. Subsequently, the inflatable bladder is inflated, the vacuum chamber is placed under at least partial vacuum pressure, and the unbonded retreaded tire is bonded to form a bonded retreaded tire by pressurizing and heating the curing chamber.

Description

METHODS OF FORMING A RETREADED TIRE

BACKGROUND OF THE INVENTION

Field of the Invention

[0001] This invention relates generally to methods and apparatuses for manufacturing retreaded tires, and treads for retreading tires. More specifically, this invention relates to methods and apparatuses for curing a retreaded tire without a curing membrane.

Description of the Related Art

[0002] A retreaded tire consists of a new pre-cured tread attached to a pre-existing tire carcass. The tire carcass is prepared to receive the new pre-cured tread by removing the prior tread, such as through buffing or abrading operations. The new pre-cured tread is then applied to the tire carcass with a bonding layer comprising bonding material to secure the new tread to the carcass. Subsequently, a flexible curing membrane (or envelope) particularly sized for use with the particularly sized tire is arranged at least partially around the tire to create a sealed fluid chamber between the curing membrane and the tire. The combination of a retreaded tire with an installed curing membrane is referred to herein as a tire-membrane assembly.

[0003] In operation, a plurality of tire-membrane assemblies are placed within a tire curing chamber, such as an autoclave (curing chamber). Each tire-membrane assembly is then placed in fluid communication with a vacuum source. The vacuum source substantially removes gas between the tire and the curing membrane. Subsequently, while under vacuum pressure, the curing chamber is also heated and positively pressurized, such that a pressure force is applied to the flexible curing membrane. Accordingly, the flexible curing membrane is forced into grooves and other sufficiently sized voids arranged along the top side (i.e. , outer or exposed side) of the tread during curing operations.

[0004] Because these flexible curing membranes are particularly sized for use with particularly sized tires, the curing membranes must be changed and replaced (i.e. , substituted) when curing differently sized tires. This reduces the efficiency in the curing process by increasing processing time. Therefore, it is desirable to develop more efficient curing processes where a flexible curing membrane is able to be used with differently sized tires. SUMMARY OF THE INVENTION

[0005] Particular embodiments of the invention concerns methods of forming a retreaded tire, and retreaded tires formed thereby. One embodiment of such methods includes providing an unbonded retreaded tire and forming a curing assembly having an inner chamber arranged along the inner side of the unbonded retreaded tire containing an inflatable bladder for applying forces against the inner side of the unbonded retreaded tire. Furthermore, a flexible curing membrane sized for use with a plurality of differently sized unbonded retreaded tires is arranged around an outer circumference of the unbonded retreaded tire to form a vacuum chamber along an outer side of the unbonded retreaded tire. Subsequently, the inflatable bladder is inflated, the vacuum chamber is placed under at least partial vacuum pressure, and the unbonded retreaded tire is bonded to form a bonded retreaded tire by pressurizing and heating the curing chamber.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] FIG. 1 is a front sectional view of components of a curing assembly prior to assembly in accordance with an embodiment of the invention.

[0007] FIG. 2 is a front sectional view of the components of FIG. 1 assembled in a curing chamber to form the curing assembly in accordance with an embodiment of the invention.

[0008] FIG. 3 is a side view of the curing assembly of FIG. 2, in accordance with an embodiment of the invention.

DETAILED DESCRIPTION OF PARTICULAR EMBODIMENTS

[0009] Particular embodiments of the invention include methods of forming a retreaded tire and a retreaded tire formed by methods described herein.

[0010] Particular embodiments of such methods include providing an unbonded retreaded tire, which comprises a pre-cured tread arranged annularly around an outer circumference of an annular tire carcass with a bonding layer comprising uncured bonding material arranged between the pre-cured tread and the annular tire carcass. The unbonded retreaded tire has a thickness extending between inner and outer sides of the unbonded retreaded tire. The annular tire carcass comprises a pair of sidewalls spaced apart in an axial direction of the tire, each of the pair of sidewalls extending radially inward from an undertread portion to a bead portion. The outer side of the unbonded retreaded tire may also be described as having a first lateral portion and a second lateral portion, which are spaced apart and arranged on opposing axial sides of the tire. Accordingly, the first lateral portion includes a first sidewall and associated bead portion and the second lateral portion includes a second sidewall and associated bead portion. It is appreciated that the unbonded retreaded tire may be assembled by any method known to one of ordinary skill in the art.

[0011] Particular embodiments of such methods further includes forming a curing assembly having an inner chamber arranged along the inner side of the unbonded retreaded tire, the inner chamber extending approximately from the first bead portion to the second bead portion. In particular embodiments, forming the curing assembly includes mounting the unbonded retreaded tire on a mount to form the inner chamber, which may be arranged between the tire and the mount, for example. It is understood that the mount may comprise a wheel, for example, or other mount known to one of ordinary skill or a mount suitable for its intended purpose of mounting the tire. For example, a wheel may be a solid wheel, or may comprise multiple components separable and configured to articulate or displace between a tire mounting and dismounting (i.e. , mounted and dismounted) configuration. It is appreciated that the inner chamber may be placed under vacuum pressure or at least partial vacuum pressure during curing operations. In doing so, the inner chamber may be directly in fluid communication with a vacuum pressure source, or indirectly by way of being in fluid communication with a vacuum chamber arranged along the outer side of the tire, which will be discussed in further detail below.

[0012] In further embodiments, an inflatable bladder is arranged in the inner chamber, the inflatable bladder being configured to expand and thereby apply forces against the inner side of the unbonded retreaded tire. In such embodiments, the inflatable bladder is arranged in fluid communication with a pressure source to facilitate inflation or pressurization. Upon pressurization, the inflatable bladder, being formed of a flexible or elastomeric material, forms a final, inflated shape and may even expand. It is noted that this force applied to the inner side of the tire assists in removing gas arranged within the unbonded retreaded tire by applying a pressure or force against the tire to forcefully dispel any gases arranged within the unbonded assembled retreaded tire and/or any gases that may arise as the bonding material cures during a curing operation.

[0013] In particular embodiments, forming a curing assembly further comprises arranging a flexible curing membrane around an outer circumference of the unbonded retreaded tire to form a vacuum chamber along an outer side of the unbonded retreaded tire, the flexible curing membrane being sized for use with a plurality of differently sized unbonded retreaded tires. By providing a vacuum chamber along the outer side of the unbonded retreaded tire, any gas contained within the tire may be evacuated or removed when placing the vacuum chamber under vacuum pressure or at least partial vacuum pressure. Accordingly, one or more vacuum chambers may be arranged along the outer side to evacuate any gas from around and within the unbonded, assembled tire. When a plurality of vacuum chambers are provided along the outer side, the plurality of vacuum chambers may be separated or may be in fluid communication with any one or more of the other vacuum chambers. In particular embodiments, the vacuum chamber extends along the outer side of the unbonded retreaded tire substantially from a first bead portion to a second bead portion of the unbonded retreaded tire. As used herein, a "vacuum chamber" is any volume or interface between materials in contact (e.g. , when a curing membrane is under at least partial vacuum pressure and collapses onto a tire by way of suction such that volume defined between them is insignificant) substantially fluidly isolated from an environment outside the chamber by substantially-impermeable materials around the chamber.

[0014] In prior art methods of curing a retreaded tire using a flexible curing membrane, the membrane is particularly sized for each particularly sized tire - in width, circumference, and aspect ratio (which is equal to half the difference between an outer diameter and the inner most diameter - taken at the bead area - of the tire). According to the present invention, however, a flexible curing membrane is provided that is configured to receive numerous substantially differently sized tires, so that the flexible curing membrane does not have to be substituted when differently sized tires are to be cured. Substantially differently sized tires have a substantially different outer diameter, width, and/or aspect ratio. For example, in particular embodiments, a retreaded tire having an outer diameter of 40 inches may be cured in the same flexible curing membrane as a tire having an outer diameter of 27 inches. In any such scenario, the tires may have the same width or substantially different widths and/or aspect ratios - in addition to having substantially different outer diameters. A substantial difference in outer diameter, width, and/or aspect ratio results in a substantially different volume formed by the tire or consumed within the flexible curing membrane. For example, in particular embodiments, a substantially different volume comprises at least a 2%, 5%, or 10% volumetric difference between tires. To achieve this substantially different volume, any one or any combination of the outer diameter, width, and/or aspect ratio may be substantially different from between tires, where, in certain exemplary embodiments, a substantially different outer diameter, width, or aspect ratio comprises at least a 2%, 5%, or 10% difference between tires.

[0015] By utilizing a flexible curing membrane configured to receive substantially differently sized tires, the efficiency of curing operations increases, and curing operations may be better automated. Therefore, to achieve its purpose, it is appreciated that the flexible membrane may comprise any form and shape configured to receive and surround the assembled tire circumference and at least the across the width of the tire from bead portion to bead portion. In particular embodiments, the flexible curing membrane, being sized for use with a plurality of differently sized unbonded retreaded tires, comprises a first portion and a second portion, the first portion being arranged along a first lateral portion of the outer side of the unbonded retreaded tire and the second portion of the flexible curing membrane being arranged along a second lateral portion of the outer side of the unbonded retreaded tire, where the first portion and the second portion together form a sealing junction.

[0016] In order to create a vacuum chamber, portions of the curing membrane come together and engage each other or another intervening member, such as a wheel, to form a sealing junction and thereby form a vacuum chamber. Such a junction may comprise a joint, an overlap, or a pleat, for example. Therefore, in particular embodiments where the curing membrane comprise first and second portions, the first and the second portions together form a sealing junction. This sealing junction maybe arranged at any location relative the tire. For example, in particular embodiments, the sealing junction is arranged along a tread portion of the outer side. It is appreciated that a sealing junction may not be achieved until the one or more vacuum chambers are placed under vacuum or partial vacuum. It is also understood that a sealing junction may be achieved in particular embodiments by mechanically applying structure to forcibly form a sealing junction, such as by clipping or pinching portions of the membrane together or in contact with another member, to close a vacuum chamber formed of at least the first and second portions.

[0017] In providing first and second lateral portions, which may also be referred to as a first side portion and a second side portion, respectively, the first and second lateral portions may be separate, independent components displaceable between enclosed and separated arrangements. For example, in particular embodiments, each of the first and second lateral portions comprise a sheet, which come into contact to form a vacuum chamber around an outer side of the retreaded tire. It is appreciated, to form a vacuum chamber around an outer side of the retreaded tire, the first and second lateral members contact each other or another intervening member substantially around the outer circumference of the retreaded tire. Contact may be achieved by using any sealing structure to force the first and second lateral portions into contact with each other or any intervening structure configured to result in a sealing junction or sealed engagement, at least when the vacuum chamber arranged along the outer side of the retreaded tire is placed under vacuum pressure or partial vacuum pressure. In certain embodiments, one of the first and second lateral portions have an aperture configured to receive a mount or wheel supporting member, where the supporting member extends from the mount or wheel to an anchoring structure. By further example, in other embodiments, the first and second lateral portions of the flexible membrane are attached to or integral with each other, such that only a portion of the perimeter surrounding the outer circumference of the retreaded tire remains to be closed to enclose the retreaded tire and to form the vacuum chamber along the outer side of the tire. It is also appreciated that sealing structure maybe provided to force one or both of the first and second members against the mount to form the vacuum chamber along the outer side of the retreaded tire. In forcing portions of the membrane into a sealing contact, sealing structure may also clamp or pinch portions of the curing membrane to maintain the sealing contact to form a sealing junction. It is appreciated that each of the first and second lateral portions may be formed or assembled from a plurality of components and may form different sections.

[0018] In particular embodiments, such methods further comprise inflating the inflatable bladder to expand and thereby apply a force against the inner side of the unbonded retreaded tire. In performing this aspect, the inflatable bladder is pressurized by a pressurization source. The pressure of the gas may be any pressure sufficient to apply a desired force against the inner side of the retreaded tire. In particular embodiments, for example, the inflatable bladder is pressurized to at least substantially 6 bars.

[0019] Particular embodiments of such methods further include placing the vacuum chamber under at least partial vacuum pressure. In particular embodiments, this occurs after inflating the inflatable bladder initializes or is completed. It is also noted that in certain instances, placing the vacuum chamber under at least partial vacuum pressure comprises placing the vacuum chamber under vacuum pressure. As discussed above, the vacuum pressure or partial vacuum pressure may be achieved by a vacuum pressure source (which may be more generally referred to as a "pressure source"). In doing so, the flexible curing membrane is in fluid communication with a vacuum source, where such communication may be direct, meaning the vacuum source maybe attached by hose or other fluid connection to the curing membrane, or indirect, such as when the vacuum chamber is in fluid communication with the inner chamber, which is attached by hose or other fluid connection to a vacuum source. As used herein, "vacuum" and "under vacuum" mean providing a fluid pressure equal to zero psia (pounds per square inch absolute), and "substantial vacuum" or "substantially under vacuum" means 5 to 0 (zero) psia. "Partial vacuum" connotes a pressure less than 14.7 psia, less than 10 psia, less than 8 psia, less than 5 psia, or less than 3 psia. Additional aspects of such methods may further include connecting a fluid passage to the curing membrane of the tire-membrane assembly to place the sealed fluid chamber in fluid communication with a pressurization source (configured to provide positive pressure and/or vacuum pressure as needed). A pressurization source may comprise a compressor or any other device known to one of ordinary skill in the art. While aspects herein are described as one or more separate vacuum and pressure sources, it is understood that such pressure or vacuum can be provided by a single pressurization source in some embodiments.

[0020] In particular embodiments, the inner chamber comprises a vacuum chamber that is placed under at least partial vacuum pressure. It is understood that the inner chamber and the vacuum chamber arranged along the outer side of the tire may each be separately arranged in fluid communication with a vacuum source, or may together be arranged in fluid communication with the same vacuum source. Further, in particular embodiments, the inner chamber is arranged in fluid communication with the vacuum chamber arranged along the outer side of the tire, such that placing any one of such chambers in fluid communication with a vacuum source places all of the chambers in fluid communication with the vacuum source. Accordingly, in particular embodiments, placing the vacuum chamber under at least partial vacuum pressure includes placing the inner chamber under at least partial vacuum pressure. In embodiments where the tire is mounted on a mount and the inner chamber is placed into fluid communication with the vacuum chamber arranged along the outer side of the tire, this may be achieved by arranging a wicking agent between the tire and the mount at a bead portion to extend from the vacuum chamber and to inner chamber to place the vacuum chamber in fluid communication with the inner chamber. The wicking agent facilitates a flow of gas or pressure between the inner and outer sides of the tire, and therefore, between the inner chamber and any vacuum chamber arranged along the outer side of the tire. The wicking agent may comprise any structure or article configured to achieve its intended purpose. For example, the wicking agent may be formed of air-permeable material, which includes woven fabric, for example, or any other air-permeable structure having or forming voids to facilitate a flow of gas or pressure between the inner and outer sides of the tire. Wicking agent materials can be selected to specifically control the amount or rate of airflow between the chambers.

[0021] Further embodiments of such methods also include bonding the unbonded retreaded tire to form a bonded retreaded tire by pressurizing a curing chamber and sufficiently heating the curing chamber to cure the bonding layer of the unbonded retreaded tire while the vacuum chambers in the curing assembly are at least under partial vacuum pressure. Generally, the curing chamber provides a controlled environment where a tire is cured or bonded in accordance with a curing law comprising a recipe or formula identifying any combination of one or more pressures and temperatures for certain durations. In such instances, the curing assembly is exposed to pressurized and heated gases contained within the curing chamber, such as in accordance with a curing law, for example, where the curing assembly is exposed to particular pressures and heat at different instances for particular durations during a curing operation. In particular embodiments, heating of the curing chamber initializes prior to inflating the inner bladder. In further instances, placing the vacuum chamber under at least partial vacuum initializes after the inner bladder is pressurized, such as to a target or desired pressure, and where the curing chamber is pressurized after the vacuum chamber is placed under at least partially vacuum.

[0022] Further embodiments of such methods include disassembling the curing assembly by separating the bonded retreaded tire from the flexible curing membrane after bonding. It is appreciated that assembly and disassembly of the curing assembly may occur within the curing chamber, external thereof, or any combination thereof. Also, assembly and disassembly may be automated, or may be performed manually.

[0023] Embodiments of such techniques are a departure from earlier curing methods that require use of a curing membrane to remain on the unbonded tire during curing.

[0024] Embodiments of the innovation disclosed herein further include bonded retreaded tires produced using the method described above.

[0025] Particular embodiments of the methods discussed above will now be described in further detail below in association with the figures filed herewith exemplifying the performance of the methods in accordance with particular embodiments of such methods.

[0026] FIGS. 1-3 generally provide an exemplary curing assembly 100. With reference to FIG. 1, various components of a curing assembly are shown prior to assembly while FIGS. 2 and 3 show the exemplary curing assembly in an assembled arrangement, in accordance with an exemplary embodiment.

[0027] In particular, the exemplary curing assembly 100 includes unbonded (assembled) retreaded tire 120 to be mounted on wheel 110 (which more generally represents a mount for the tire). Wheel 110 is shown to comprise multiple components, such as first portion 112 and second portion 114, which when assembled, includes a retreaded tire mounted thereon. By doing so, the tire may be mounted on the wheel more easily in automated processes. In other embodiments, the tire may be mounted manually in accordance with known mounting methods. Other known mounting methods may also be employed in cooperation with other aspects of these methods.

[0028] Unbonded retreaded tire 120 includes a tire carcass 121, bonding layer 122, and tread 123. Bonding layer 122 comprises uncured bonding material and is disposed between tire carcass 121 and tread 123 for bonding the tread to the tire carcass. The tread 123 is a pre-cured tread arranged annularly around an outer circumference of an annular tire carcass. The tire carcass, as well as the assembled retreaded tire, includes a pair of opposing sidewalls 124 forming a lateral portion or side of the tire and tire carcass and a pair of opposing bead portions 125 from which one of the sidewalls extend. It is also noted that the tire has a thickness extending between an outer side 126 and an inner side 127 of the tire. In embodiments, unbonded retreaded tire 120 can be provided preassembled, where the tire carcass 121, bonding layer 122, and tread 123 are assembled together when provided to the curing chamber. Alternatively, the tire could be assembled within the curing chamber, whereby such components are provided for assembly.

[0029] In FIGS. 1 and 2, a first wicking agent 114 is shown arranged between the unbonded retreaded tire 120 and wheel 110, extending from the outer side 126 and the inner side 127 of the tire. As discussed above, the wicking agent facilitates a flow of gas or pressure between the inner 127 and outer 126 sides of the tire, and ultimately, when formed, a vacuum chamber 151 arranged along the outer side of the tire and an inner chamber 152 arranged along the inner side of the tire. In this way, vacuum source 154 can operate to remove air from both the vacuum chamber 151 and the inner chamber 152 while only being directly connected to one of the chambers. By example, the vacuum source 154 is connected to the vacuum chamber 151. It is appreciated that the wicking agent may be arranged at a single location around the tire such that the wicking agent extends less than 360 degrees around the wheel or tire. Still, in particular embodiments, the wicking agent may extend substantially 360 degrees around the wheel or tire. In still other embodiments, one or more additional wicking agents may be employed on the same lateral side of the wheel or tire, and/or on the opposing lateral side of the wheel or tire, such that a plurality of wicking agents are employed. In alternative embodiments, vacuum chamber 151 is sealed from the inner chamber 152 to prevent fluid communication there between.

[0030] With continued reference to FIGS. 1-3, a flexible curing membrane 130, sized for use with a plurality of differently sized unbonded retreaded tires, is configured to be arranged (see FIG. 1) and arranged (see FIGS. 2 and 3) about an unbonded retreaded tire 120 to form one or more vacuum chambers about the outer side of the tire (each of which are also referred to as an "outer chamber"). With specific reference to FIGS. 2 and 3, upon installation, the flexible curing membrane 130, in combination with the unbonded retreaded tire 120 and the wheel 110, forms one or more vacuum chambers 151 along an outer side of the retreaded tire 120. Upon mounting the tire upon the wheel, an inner chamber 152 is formed along the inner side 127 of the tire, generally between the inner side and the wheel 110.

[0031] As stated above, a curing membrane may comprise a plurality of portions. In the exemplary embodiment shown in FIGS. 1-3, curing membrane 130 includes a first lateral portion 131 and second lateral portion 132. While each of the first and second lateral portions may be configured to extend at least partially across an entire lateral side of a tire, first lateral portion 131 is configured to extend across an entire lateral side of the tire and wheel while the second lateral portion 132 is configured to extend partially across a second lateral side of the tire and wheel. In particular, the second lateral portion 132 is configured to extend from an outer circumference of the tire to at least a circumferential portion of the lateral side of the wheel to allow a wheel support 160 to access to the wheel to which it is operably attached. It is appreciated that each such first and second lateral portion may be formed of multiple separate portions.

[0032] As discussed above, the curing membrane is configured to be sufficiently sealed to maintain at least partial vacuum pressure within the vacuum chamber. In the embodiment shown, sealing structures 140, 141 are employed to form a sealing junction 133 between first and second lateral portions, whereby the sealing structures force the first and second lateral portions into contact. The embodiment shown also includes sealing structures 142, 143, which are also employed to force the first and second lateral portions 131, 132 respectfully against the wheel 110. In lieu of sealing structures articulating between sealed and unsealed arrangements, one or both of the first and second lateral portions may be permanently or temporarily attached in a sealed arrangement to the wheel by a sealing structure.

[0033] As noted above, first lateral portion 131 and second membrane portion 132 meet at sealing junction 133. In the present embodiment, the sealing junction comprises a joint, but in other embodiments, the junction may comprise an overlap or a pleat, for example. In certain embodiments, the sealing junction is achieved by virtue of placing the vacuum chamber under vacuum or partial vacuum pressure. In other embodiments, a sealing junction is achieved by forceful engagement, such as by pushing, clipping, or pinching the terminal ends together or in contact with another member, to close a vacuum chamber formed of at least one of the first and second portions. While first and second lateral portions 131, 132 are shown as substantially symmetrical relative the tire, and connecting approximately half-way about the exterior bead-to-bead path, toward the middle of tread 123, it is understood that asymmetrical arrangements can be employed without departing from the scope or spirit of the innovation.

[0034] In certain embodiments, curing assembly 100 further includes inflatable bladder 137. In the mounted arrangement, inflatable bladder 137 is disposed within an inner chamber 152 formed between an inner side 127 of the tire and the wheel 110. Inflatable bladder 137 can be inflated and pressurized using pressure provided by a pressure source 156. Inflatable bladder 137 is configured to fill at least a portion of the space within the inner chamber, to thereby reduce the volume of second vacuum chamber 152 between the bladder and the inner side 127 of the tire. By forcefully engaging the inner side 127 of the tire, inflatable bladder 137 assists in expelling any gas arranged within the unbonded retreaded tire before the tire is bonded. In particular embodiments, inflatable bladder 137 may be formed of two or more distinct parts to facilitate installation, repair, stories, particular geometries, or other ends.

[0035] Turning now to FIG. 2, curing assembly 100 is arranged in a curing chamber. A curing chamber may include a curing assembly support structure 160 used to suspend the curing assembly, and which is operably connected to the wheel. To provide heat as desired to cure the bonding layer, a heater 158 is provided. The heater, or any arrangement of heaters may be employed as known by one of ordinary skill.

[0036] The present invention may be utilized in association with retreaded tires, which may be utilized on particular types of vehicles or in specific applications. Nevertheless, the present invention may be utilized in association with any type of tire to form new or retreaded tire and as such, any type of tire may provide an embodiment of the present invention. Exemplary tire types for use with the subject invention further include light truck tires, heavy truck tires, off the road tires, bus tires, aircraft tires, bicycle tires, motorcycle tires, and passenger vehicle tires.

[0037] The terms "comprising," "including," and "having," as used in the claims and specification herein, shall be considered as indicating an open group that may include other elements not specified. The terms "a," "an," and the singular forms of words shall be taken to include the plural form of the same words, such that the terms mean that one or more of something is provided. The terms "at least one" and "one or more" are used interchangeably. The term "single" shall be used to indicate that one and only one of something is intended. Similarly, other specific integer values, such as "two," are used when a specific number of things is intended. The terms "preferably," "preferred," "prefer," "optionally," "may," and similar terms are used to indicate that an item, condition or step being referred to is an optional (i.e., not required) feature of the invention. Ranges that are described as being "between a and b" are inclusive of the values for "a" and "b" unless otherwise specified.

[0038] While this invention has been described with reference to particular embodiments thereof, it shall be understood that such description is by way of illustration only and should not be construed as limiting the scope of the claimed invention. Accordingly, the scope and content of the invention are to be defined only by the terms of the following claims. Furthermore, it is understood that the features of any specific embodiment discussed herein may be combined with one or more features of any one or more embodiments otherwise discussed or contemplated herein unless otherwise stated. As used herein, the term process or method refers to one or more steps that may be performed in any order without departing from the scope of the invention. Also, some steps may be optional and may be omitted.

Claims

CLAIMS What is claimed is:

1. A method of forming a retreaded tire comprising:

providing an unbonded retreaded tire, which comprises a pre-cured tread arranged annularly around an outer circumference of an annular tire carcass with a bonding layer comprising uncured bonding material arranged between the pre-cured tread and the annular tire carcass, the unbonded retreaded tire having a thickness extending between inner and outer sides of the unbonded retreaded tire, where the annular tire carcass comprises a pair of sidewalls spaced apart in an axial direction of the unbonded retreaded tire, each of the pair of sidewalls extending radially inward from an undertread portion to a bead portion;

forming a curing assembly by mounting the unbonded retreaded tire on a mount to form an inner chamber along the inner side of the unbonded retreaded tire between the mount and the unbonded retreaded tire extending approximately from the first bead portion to the second bead portion, where an inflatable bladder is arranged in the inner chamber, the inflatable bladder being configured to expand and thereby apply forces against the inner side of the unbonded retreaded tire;

where forming a curing assembly further comprises arranging a flexible curing membrane around an outer circumference of the unbonded retreaded tire to form a vacuum chamber along an outer side of the unbonded retreaded tire, the flexible curing membrane being sized for use with a plurality of differently sized unbonded retreaded tires and comprising a first portion and a second portion, the first portion being arranged along a first lateral portion of the outer side of the unbonded retreaded tire and the second portion of the flexible curing membrane being arranged along a second lateral portion of the outer side of the unbonded retreaded tire, where the first portion and the second portion together form a sealing junction,

inflating the inflatable bladder to expand and thereby apply a force against the inner side of the unbonded retreaded tire;

placing the vacuum chamber under at least partial vacuum pressure;

bonding the unbonded retreaded tire to form a bonded retreaded tire by pressurizing a curing chamber and sufficiently heating the curing chamber to cure the bonding layer of the unbonded retreaded tire while the vacuum chamber in the curing assembly are at least under partial vacuum pressure.

2. The method of claim 1, where the vacuum chamber extends along the outer side of the unbonded retreaded tire substantially from a first bead portion to a second bead portion of the unbonded retreaded tire.

3. The method of claim 1, where the sealing junction is arranged along a tread portion of the outer side.

4. The method of claim 1 further comprising:

placing the inner chamber under at least partial vacuum pressure.

5. The method of claim 4, where placing the vacuum chamber under at least partial vacuum pressure includes placing the inner chamber under at least partial vacuum pressure.

6. The method of claim 5, where the inner chamber is in fluid communication with the vacuum chamber arranged along the outer side of the unbonded retreaded tire.

7. The method of claim 6, where a wicking agent is arranged between the tire and the mount at a bead portion to extend from the vacuum chamber and to inner chamber to place the vacuum chamber in fluid communication with the inner chamber.

8. The method of claim 1, where the first and second portions of the flexible curing membrane are forced together to form the sealing junction.

9. The method of claim 8, where the first and second portions of the flexible curing membrane are each forced against the mount to form a sealing junction with the mount.

10. The method of claim 1, where forming a curing membrane is automated.

11. The method of claim 10, where forming a curing assembly is performed within the curing chamber.

12. The method of claim 1, where heating of the curing chamber initializes prior to inflating the inner bladder.

13. The method of claim 12, where placing the vacuum chamber at least partial vacuum initializes after the inner bladder is pressurized and where the curing chamber is pressurized after the vacuum chamber is placed under at least partially vacuum.

14. A retreaded tire formed by a process comprising:

placing the vacuum chamber under at least partial vacuum pressure;

15. The retreaded tire of claim 14, where the process by which it is formed further comprises:

placing the inner chamber under at least partial vacuum pressure.

16. The retreaded tire of claim 15, where placing the vacuum chamber under at least partial vacuum pressure includes placing the inner chamber under at least partial vacuum pressure.

17. The retreaded tire of claim 16, where the inner chamber is in fluid communication with the vacuum chamber arranged along the outer side of the unbonded retreaded tire.

18. The retreaded tire of claim 17, where a wicking agent is arranged between the tire and the mount at a bead portion to extend from the vacuum chamber and to inner chamber to place the vacuum chamber in fluid communication with the inner chamber.

19. The retreaded tire of claim 14, where the first and second portions of the flexible curing membrane are forced together to form the sealing junction.

20. The retreaded tire of claim 19, where the first and second portions of the flexible curing membrane are each forced against the mount to form a sealing junction with the mount.