WO2013002797A1

WO2013002797A1 - Apparatus and methods for aligning treads during tire retreading operations

Info

Publication number: WO2013002797A1
Application number: PCT/US2011/042540
Authority: WO
Inventors: Metodi L. Ikonomov; Nathan J. Panning
Original assignee: Michelin Recherche Et Technique S.A.; Compagnie Generale Des Etablissements Michelin
Priority date: 2011-06-30
Filing date: 2011-06-30
Publication date: 2013-01-03

Abstract

Embodiments of the invention include methods and apparatus for constraining a tread in a desired arrangement about a tire carcass during retreading operations. Such methods include providing an annular tire carcass configured for receiving a tread and arranging a tread annularly about the precured tire carcass in a desired position. Such methods include constraining the tread in the desired position by arranging a tread alignment fixture about an outer side of the tread. In particular embodiments, the fixture comprises a body comprising one or more members arranged annularly about a central axis, the one or more members having a width extending axially relative the central axis and one or more tread-engaging protrusions extending radially inward relative the central axis and lengthwise in a circumferential direction.

Description

APPARATUS AND METHODS FOR ALIGNING TREADS DURING TIRE

RETREADING OPERATIONS

BACKGROUND OF THE INVENTION

Field of the Invention

[0001] This invention relates generally to methods and an apparatus for retreading tires, and more particularly, to methods and an apparatus for maintaining treads in a desired arrangement atop a cushion rubber layer and about a tire casing during retreading operations.

Description of the Related Art

[0002] When a tread, such as a pre-cured tread, is placed over an uncured cushion rubber layer, the tread may shift laterally (i. e. , axially) as the cushion rubber is heated during curing operations. Without the tread being held in a generally fixed position, the tread may tend to deviate from a desired position. For example, if a pre-cured tread has thin regions, such as below tread grooves, and pressure is applied to the tire in a pressurized autoclave (i.e. , a curing chamber), the hot, relatively fluid cushion rubber becomes pressurized and can deform and alter the tread while the cushion rubber is being cured. In particular instances, this deformation of the groove bottoms and ribs can create non-uniformities in the retread tire as well as reducing the effective groove depth.

[0003] Therefore, there is a need to stabilize the pre-cured tread to obtain a more uniform retread placement by providing a stabilizer or fixture about the tread that maintains the tread in a desired geometry.

SUMMARY OF THE INVENTION

[0004] Particular embodiments of the present invention include methods and apparatus for stabilizing the process of retreading a tire. Particular embodiments of such apparatus include a tire tread alignment fixture for positioning a tire tread along a pre-cured tire carcass during tire retreading operations, the fixture including a body comprising one or more members arranged annularly about a central axis, the one or more members having a width extending axially relative the central axis and one or more tread-engaging protrusions extending radially inward relative the central axis and lengthwise in a circumferential direction.

[0005] Particular embodiments of such methods comprise methods for retreading a tire carcass. Such methods include the steps of providing a pre-cured annular tire carcass configured for receiving a tread and arranging a tread annularly about the precured tire carcass in a desired position to form an assembled retreaded tire. Such methods further include the step of constraining the tread in the desired position by arranging a tread alignment fixture about an outer side of the tread.

[0006] The foregoing and other objects, features and advantages of the invention will be apparent from the following more detailed descriptions of particular embodiments of the invention, as illustrated in the accompanying drawings wherein like reference numbers represent like parts of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] FIG. 1 is a partial perspective view of a sectioned tire tread alignment fixture shown arranged on an outer side of an annular tread of a retreaded tire, according to an exemplary embodiment.

[0008] FIG. 2 is a side view of the tire tread alignment fixture shown in FIG. 1.

[0009] FIG. 3 is a cross-sectional view of a tire tread alignment fixture arranged along an outer tread surface of a retreaded tire, the fixture including two link assemblies arranged along an outer side of the fixture, according to another embodiment of the present invention.

[0010] FIG. 4 is a cross-sectional view of a tire tread alignment fixture arranged along an outer tread surface of a retreaded tire, the fixture including a single link assembly arranged along an outer side of the fixture, according to another embodiment of the present invention.

[0011] FIG. 5 is a perspective view of the bottom of the sectioned tire tread alignment fixture shown in FIG. 1.

[0012] FIG. 6 is a side view of a multi-segmented tire tread alignment fixture arranged in a ring arrangement along an outer side of a tire, the ring comprising a closed ring formed of a plurality of engaging segments according to another embodiment of the present invention.

[0013] FIG. 7 is a perspective view of a sectioned tire tread alignment fixture shown arranged about an outer side of the tread, the tire carcass, tread, and fixture being arranged within an annular curing membrane according to an embodiment of the invention. [0014] FIG.8 is a cross-sectional view of the sectioned tire tread alignment fixture arranged about an outer side of a tire tread, the tread, tire carcass, and fixture being arranged within the annular curing membrane shown in FIG.7.

[0015] FIG.9 is a perspective view of a sectioned tire tread alignment fixture shown arranged about an outer side of a tire tread and a curing bladder arranged within a central chamber of the tire for performing curing operations to cure the retreaded tire, according to an embodiment of the invention.

[0016] FIG.10 is a cross-sectional view of the sectioned tire tread alignment fixture arranged about an outer side of a tire tread with a curing bladder arranged within a central chamber of the tire shown in FIG.9.

[0017] FIG.11 is a perspective section view of a sectioned tire tread alignment fixture comprising an elastic ring for arrangement within a tread recess, such as a longitudinal groove, according to another embodiment of the present invention.

[0018] FIG.12 is a cross-sectional view of a several tire tread alignment fixtures of the type shown in FIG.11 arranged along an outer tread surface of a retreaded tire, each fixture comprising an elastic ring arranged within a recess (i.e. , a circumferential groove) along an outer side of the tread, according to another embodiment of the present invention.

DETAILED DESCRIPTION OF PARTICULAR EMBODIMENTS

[0019] Particular embodiments of the present invention provide methods and apparatus for stabilizing (i.e. , constraining or maintaining) a tread in a desired arrangement about a tire carcass or casing when in forming a retreaded tire. By employing such methods and apparatus, the tread arranged about the tire carcass is better aligned during the retreading operations. Particularly, such methods and apparatus maintain the tread in a desired arrangement during a curing process in which the tread is cured or fixedly attached to the tire carcass to form a cured retreaded tire. Further, the tread is maintained in a lateral or axial arrangement relative to the tire, to prevent substantial sideways (i.e. , lateral or axial) movement or deviation from the desired arrangement. Circumferential or rotational translation about the tire carcass may also be reduced by employing the methods and apparatus discussed herein. [0020] Such methods may comprise methods for retreading a tire carcass, which may comprise a variety of steps. In particular embodiments, such methods include the step of providing a pre-cured annular tire carcass configured for receiving a tread. Further steps of such methods may include the step of arranging a tread annularly about the precured tire carcass in a desired position to form an assembled retreaded tire. The step of arranging may include arranging a curable joining material between the tire carcass and the tread.

[0021] Tire retreading generally comprises placing a new tread on a pre-existing tire carcass. The tire carcass may be prepared to receive the new tread by any known means, such as by buffing, grinding, abrading, or cutting the prior tread from the carcass. The new tread may be molded, and fully or partially cured prior to its application upon a tire carcass. In other variations, such treads may remain uncured when applied to a tire carcass. Prior to applying the tread to the tire carcass, a joining material (i.e., a bonding material) may be arranged between the tread and the tire carcass to promote adhesion there between. The joining material may comprise any known material for bonding the tread to the tire carcass. For example, the joining material may comprise a material curable by way of a vulcanization, such as natural or synthetic rubber or any other polymeric material, which is commonly referred to as liaison rubber or cushion gum. Joining material may further comprise an adhesive or the like.

[0022] Particular embodiments of such methods may include the step of constraining the tread in the desired position by arranging a tread alignment fixture about an outer side of the tread. The fixture may retain the tread in a desired lateral position relative the tire carcass. Additionally, the fixture may retain the tread in a desired circumferential position about the tire carcass. It is understood that the tread alignment fixture may comprise any fixture contemplated in the discussion below, including the fixtures described in the figures filed herewith.

[0023] To form a retreaded tire, the assembled retreaded tire having an uncured bonding layer must be cured to bond the tread to the tire carcass. Any method known in the art may be employed to cure the uncured, assembled retreaded tire. For example, the assembled, but the assembled retreaded tire may be arranged within a curing chamber known as an autoclave, where the tire is at least partially surrounded by air or other fluids heated and pressurized according to desired curing formulas or laws. Accordingly, particular embodiments of methods for tire retreading further include the step of placing the assembled retreaded tire with the fixture arranged thereabout into a curing chamber. Because the tread alignment fixture maintains the alignment of the tread as the interface between the tread and the tire carcass becomes pliable and malleable, the assembled, assembled retreaded tire is arranged within the curing chamber with the fixture affixed or applied to the tire.

[0024] It follows that such methods comprise the additional step of curing the retreaded tire within the curing chamber. This may include applying pressurized and heated fluids about the tire, or at least about an outer side of the assembled retreaded tire. This may also include expanding a curing bladder, such as by filling the curing bladder with a heated, pressurized fluid, within a central cavity of the tire carcass. Other variations may be employed based upon the curing system or method employed. In particular embodiments, for example, the uncured, assembled retreaded tire is placed at least partially within a curing membrane or envelope for curing operations within a curing chamber. The curing membrane generally engages the outer side or surface of the tire carcass and tread, to form a skin-like member thereon at least extending circumferentially about the tire and laterally between opposing sidewalls and about the tread of the assembled tire. Any known membrane known in the art may be used. For example, one such membrane that extends around the entire tire - circumferentially and laterally. By further example, the tire may be mounted on a wheel while a membrane extends from sidewall to sidewall about the tread. Regardless of the membrane employed, a compartment is generally be formed between the membrane and the tire (tread and/or tire carcass), which may be pressurized as desired during curing operations. Accordingly, such methods may include the step of inserting the assembled retreaded tire into a flexible curing membrane, the membrane engaging at least a portion of the outer side of the retreaded tire and an outer side of the tread alignment fixture, wherein the step of placing the assembled retreading tire with the fixture arranged thereabout occurs with the retreaded tire and fixture arranged within the flexible curing membrane.

[0025] Exemplary embodiments of a tread alignment fixture for use in performing such methods of retreading a tire carcass are discussed in further detail below. The device(s) shown in the figures are only exemplary of any of a variety of tread alignment fixtures that may be employed within the scope of this invention.

[0026] With reference to FIGS. 1-4, a tread alignment fixture 10 is shown for arrangement about a tread 34 arranged along a retreaded tire 30. Tire 30 generally includes an outer side 30s extending between opposing sidewalls 32 and about an outer, exposed side 34s of tread 34. Tread 34 is mounted along a tire carcass 40 with a layer of joining material 46 arranged there between. Tread sides 36 are arranged on opposing sides of the tread width W30. As discussed above, tread 34 may be uncured or precured (partially or fully), and joining material 46 may or may not be arranged within the retreaded tire.

[0027] Fixture 10 generally includes a body 12 comprising one or more members 14 arranged annularly about a central axis, which is exemplarily shown in FIGS. 1-4. Body 12 and each member 14 includes a width W12 extending axially (i.e. , laterally) relative the central axis. In the embodiment shown, body 12 and each member 14 further includes an exposed inner side 16 configured to engage an outer exposed side of an annular tread. The inner side 16 includes one or more tread-engaging protrusions 18 extending radially inward relative the central axis and lengthwise generally in a circumferential direction. The tread- engaging protrusions 18 are arranged to extend circumferentially for the purpose of interfering with laterally adjacent portions of the tread to resist any axial (i.e. , lateral) movement of the tread relative the tire carcass.

[0028] Body 12 and each member 14 may further include outer connecting portions 22 shown exemplarily in FIGS. 1-5. The connecting portions 22 extend laterally across the outer side of tread 34 for the purpose of rigidly connecting adjacent tread engaging protrusions 18 (at least providing a rigid connection in the lateral direction), which extend inwardly from the outer connecting portions 22. In the embodiment shown, outer portions 22 also extend circumferentially with each protrusion 18, although each may extend different circumferential distances as desired. Also shown in the FIGS. 1-4, the connection portions are shaped to an outer surface of each tread rib or lug 38, and to which each connecting portion 22 engages in the installed arrangement. It is understood, however, that connecting portions 22 may be shaped in any manner, and may not engage the tread when the fixture is arranged in an installed arrangement about the tread.

[0029] Tread-engaging protrusions 18 may be arranged at different locations across the width of body 12 and each member 14 to comprise interior protrusions 18A or side protrusions 18B. With continued reference to FIGS. 1-5, tread-engaging protrusions 18 comprise interior protrusions 18A configured to engage a recess arranged along the tread outer side 34s between lateral tread sides 36. The recess 35 may comprise any recess that is bounded on at least one lateral side by a portion of the tread. For example, the recess may comprise a circumferentially extending tread groove 35 as shown, which is bounded laterally by ribs or lugs 38 of the tread. Because circumferential grooves 35 may extend in a pure circumferential path (that is, a path normal to the rotational axis of the tire), interior protrusions 18A may also extend in a pure circumferential direction as shown in FIGS. 1-5. Circumferential grooves 35, however, may also extend circumferentially along a path that also extends laterally, such as along a path that alternates (i.e. , zig-zags) laterally while generally extending lengthwise in a circumferential direction. In such instances, the interior protrusions 18A may also extend along a similarly alternating circumferential path, while a pure circumferential path may be followed if the width of the protrusion 18A can be sufficiently sized to extend lengthwise in a circumferential direction through the alternating groove.

[0030] While protrusions 18A may be configured to extend within circumferential grooves 35, protrusions 18A may also be configured to extend lengthwise in a lateral direction for arrangement within a laterally extending recess (such as a laterally extending groove). This may occur, for example, when the lateral groove terminates into an adjacent raised portion of the tread, such as a tread rib or lug, which allows the tread to engage and interfere with the protrusion 18A to resist any lateral movement of the tread relative the tire carcass.

[0031] It is understood that interior protrusions 18A may extend radially inward any desired distance sufficient to penetrate any desired recess 35, such that any protrusion 18A is arranged adjacent to a raised portion of the tread surrounding the recess. For example, with reference to FIG. 3, interior protrusions 18A may extend inwardly the full depth of tread recess 35, and even beyond such recess if the recess extends through the tread as shown. In such instance, the protrusion 18A may arrange a terminal end 20 thereof into engagement with, or within a recess arranged in, the tire carcass 40 or the joining material 46. For example, the interior protrusions shown in FIG. 3 are arranged within a carcass recess 42 formed along an outer surface of the tire carcass 40. Such carcass recess 42 may comprise any form, such as a continuous or discontinuous groove extending around the tire carcass 40. By extending into the carcass recess 42 or into engagement with the tire carcass 40, the protrusion 18A is better constrained laterally relative to the tire carcass as the adjacent raised portions of the tire carcass 40 surrounding the recess will engage and interfere with the protrusion 18A if attempting to deviate laterally from a desired arrangement. If the fixture remains laterally constrained, the tread 34 will maintain proper lateral alignment relative to the tire carcass 40.

[0032] It may also be desirous for any interior protrusion 18A to extend its terminal end 20 to the bottom of a tread recess 35 (a tread recess having a bottom is shown exemplarily in FIG. 4). By doing so, the protrusions 18A may reduce any buckling of the recess bottom (e.g. , a bottom of a groove) that may otherwise be thin and/or less rigid - and therefore more susceptible to pressures created under the tread as any joining material becomes malleable during tire curing operations. By engaging the bottom of a groove, or even the carcass or joining material, the protrusion may cause compression along the surface it engages, which may further constrain the fixture.

[0033] It is understood, however, that each protrusion 18A may not extend the full depth of any tread recess 35 or even there beyond while constraining the tread 34 at least laterally in a desired arrangement. With reference to FIG. 4, interior protrusions 18A are shown extending less than the full depth of the tread recesses 35. By not extending the interior protrusions 18A fully into a recess, the fixture may be adaptable to similar tread patterns of different depth, meaning that the recesses may be of similar geometry except that the depth of said recesses may be different amongst different treads.

[0034] With further reference to FIGS. 3-4, interior protrusions 18A may extend radially inward at any angle relative to the tread or tire centerline CL. Accordingly, the interior protrusions 18A may extend at an angle similar to a side of the recess into which the protrusion is arranged to enter. For example, as shown, interior protrusions 18A extend at a an angle similar to the angle of a sidewall of a corresponding circumferential groove 35, such that each interior protrusion is generally in full engagement with each adjacent portion of the groove sidewall. In other variations, interior protrusions 18A may extend at a greater angle, such that only a portion of the interior protrusion 18A engages the recess sidewall along the depth of the recess.

[0035] As noted above with reference to FIGS. 1-5, tread-engaging protrusions 18 also comprise side protrusions 18B configured to extend along tread sides 36. Side protrusions 18B may extend radially inward any desired distance. For example, with reference to FIG. 3, side protrusions 18B may extend inward a distance sufficient to engage a tread side 36. This may be desirous when the interior protrusions extend the full depth of any recess 35, such as is shown by example in FIG. 3. However, each side protrusion 18B may extend further to not only engage a tread side 36, but also engage a side 44 of the tire carcass. By engaging a side 44 of the tire carcass, the side protrusion 18B and the fixture 10 are better able to resist lateral movement in a direction toward tread and tire centerline CL as the side protrusion 18B engages the tire carcass 40. These carcass-engaging side protrusions 18B may be desirous when the interior protrusions 18A do not extend fully into a tread recess 35, such as is shown by example in FIG. 4. [0036] It is understood that any quantity of tread-engaging protrusions 18 may be arranged laterally along body 12 and any members 14. Further, interior protrusions 18A and side protrusions 18B may coexist as generally represented in FIGS. 1-4, or each may be utilized without the presence of the other along body 12 or any member 14.

[0037] As discussed above, body 12 comprises of one or more members 14 arranged annularly. In certain embodiments, with reference to FIGS. 11-12, for example, body 12 comprises a single member 14 forming a continuous ring, which may be formed according to any known process, such as molding or extrusion with subsequent joining of opposing free ends. Such ring 14 may be formed of elastic material capable of expanding to arrange the ring about the tread and which subsequently contracting about the tread to arrange the ring in an installed arrangement. The elastic material may comprise any natural or synthetic rubber or any other polymeric material, which may or may not be reinforced by any known means, such as by arranging cords or other known textiles within the elastic material. Such ring 10 may also include one or more projections 18A configured to extend into a recess 35 of a tread 34, where such recess may comprise a groove 35 extending along the tread, for example. Such protrusion 18A may be shaped as desired and described in conjunction with other protrusions 18A discussed elsewhere within this document. In other variations, the single member body may comprise a ring having opposing terminal ends. Such a ring may be formed of a rigid material, whereby the terminal ends are used to expand and contract the rigid ring into an installed arrangement about the tread. In either embodiment, the ring may (or may not) be configured to exude compressive forces upon the tread to assist in constraining the fixture and the tread relative to the tire carcass.

[0038] Now, with reference to the embodiments shown in FIG. 6, body comprises a plurality of members 14 forming ring segments. The members or segments 14 are arranged circumferentially in a ring arrangement. As exemplarily shown in FIG. 6, the segments 14 may be spaced about the tread 34 in the ring arrangement. Such segments 14 may remain spaced by a desired gap about the tread uniformly or non-uniformly. Further, segments 14 may form a substantially closed ring arrangement, where little or no gap is provided between adjacent segments 14. In any event, each segment 14 extends lengthwise in a circumferential direction of the tread 34 or about a central axis A about which the body 12 (comprising members or segments 14) is annularly arranged. Accordingly, the lengthwise extension of body 12, as well as any other feature of said body, including as any protrusion 18 and any connector 22, may extend lengthwise in an arcuate or curvilinear path or a linear path. A linear path may be used, for example, when the length of each member or segment is relatively small.

[0039] In each instance shown in FIG. 1-4, body 12 and each member 14 has a width Wi2 extending a distance at least equal to the full width W30 of tread 34. It is understood, however, that the width W12 may be less than the full tread width W30. In such arrangement, body 12 may comprise one or more interior protrusions 18A without any side protrusions 18B.

[0040] As has been stated, body 12 and any members 14 are arranged in an annular arrangement when installed about at tread. In an effort to maintain the annular arrangement, with reference to FIGS. 1-5, links 24 may be arranged between adjacent members 14 (or opposing terminal ends of a single member 14, which is not shown). The link may comprise any known apparatus or means for linking adjacent members. For example, said links 24 may be elastic (i.e. , capable of expanding and contracting circumferentially) or rigid circumferentially yet pivotable such that each member 14 may pivot relative to an adjacent member 14 relative central axis A. By further example, with reference to the exemplary embodiment shown in FIGS. 1-5, each link 24 may be both pivotable and elastic in the sense that a pin spring 29 allows each link to pivot as well as translate circumferentially between an expanded arrangement and a contracted arrangement. Specifically, each link 24 includes a plurality of base members 25 arranged atop (i. e. , on an outer side of) each member 14 in a circumferential arrangement, each base member 25 being arranged adjacent another and including a first circumferential end 25A and a second circumferential end 25B. First circumferential end 25A includes an extension 26 protruding outwardly from base 25, the base including with an aperture 26A extending axially there through. Second circumferential end 25B includes laterally spaced loops 28 extending radially outward from base 25. The loops 28 are laterally spaced a distance sufficient to arrange there between a circumferential extension 26 from an adjacent base 25 (arranged along an adjacent member 14). Each loop includes an aperture 28A arranged laterally opposite the other loop such that a spring pin 29 is arranged to extend through each loop and the aperture 26A of a circumferential extension 26 of an adjacent base 25 arranged there between. Spring pin 29 includes deflecting members 29B arranged about a central pin 29A, the deflecting members 29B deflecting upon application of sufficient force to thereby act as springs and expand and contract body 12 as desired about tread 34. In lieu of spring pin 29, any other known pin (unsprung) may be used. And more generally, as suggested previously, in lieu of link 24, any other link known to one of ordinary skill may be employed to join adjacent members 14, including an elastic band that extends about all of the members 14 and which may engage and/or operably attach to each such member.

[0041] Each link 24 may be affixed to body 12 or any segment 14 according to any known method. For example, any fastener(s), adhesive (permanent or temporary), or welds may be employed. Further, each link 24 maybe formed with body 12, such as with each segment 14, for example. In such instances, base 25 may comprise a connecting portion 22, such that each base 26 and loop 28 extends from an outer side of connecting portion 22. In other variations, each link 24 is separable from body 12 and any segment 14. Accordingly, each link 24 may remain operably attached to each adjacent link 24 to form an annular arrangement of links 24, which may remain in the annular arrangement as different bodies 12 and segments 14 are removed and received to accommodate different treads for different retreading operations. In summary, body 12 and any segments 14 may be permanently fixed to links 24 or may be separable there from, and links 24 may be arranged in an annular arrangement, the arrangement being separable from body 12 and any segments 14.

[0042] Body 12 and each linkage assembly 24 may be formed of any material suitable for its intended use, including any rigid or elastic material capable of withstanding the high temperatures and pressures associated with a retreading curing process. Such materials may include steel, stainless steel, thermoplastics, ceramics, and any other rigid material known by one of ordinary skill in the art.

[0043] As suggested above, the tire tread 34 and carcass 40 may be bonded together according to any known method to form a cured retreaded tire. In one example, with reference now to FIGS. 7-8, an exemplary curing membrane 50 is arranged about an outer side of the tire carcass 40, the tread 34, and the tread alignment fixture 10 arranged thereon for use in performing a particular curing process. The exemplary membrane comprises a first portion 50A extending between an outer side of each side wall 32 and about an interior side of the tire and an overlapping second portion 50B extending from an outer side of each side wall 32 and about the tire tread 34 and fixture 10. In such an arrangement, links 24 are arranged between the members 14, although it is understood that links 24 may not be employed as the curing membrane 50 may sufficiently maintain the annular arrangement of members 14. For example, the elastic properties of the curing membrane 50 may sufficiently maintain the annular arrangement of members 14. Further, vacuum pressure applied internally within the curing membrane 50 - between the tire tread 34 and carcass 40 and the membrane 50 - and/or pressure applied to an outer side of the curing membrane 50 during retread curing operations may also sufficiently maintain the annular arrangement of members 14. Other curing membranes known in the art may be employed in lieu of the membrane shown, and fixture 10 may be arranged therein for curing operation.

[0044] In other exemplary curing methods, with reference to FIGS. 9-10, an inflatable bladder 60 may be arranged within the central cavity within tire carcass 40. Such bladder 60 is generally formed of an elastic material that expands as the internal fluid pressure P increases. Upon sufficient expansion, bladder 60 contacts the interior side of the tire carcass 40 to thereby force the tread 34 against the fixture 10. In such an arrangement, by forcing the tread against the fixture may assist the fixture in constraining the tread in a desired position. To achieve this, any elastic or expandable links 24 including any elastic or expandable members (such as springs or other members formed of elastic material that allow the members 14 to expand and contract positionally) should be selected to at least partially resist the forces being applied by bladder 60.

[0045] While this invention has been described with reference to particular embodiments thereof, it shall be understood that such description is by way of illustration and not by way of limitation. Accordingly, the scope and content of the invention are to be defined only by the terms of the appended claims.

Claims

CLAIMS What is claimed is:

1. A tire tread alignment fixture for positioning a tire tread along a pre-cured tire carcass during tire retreading operations, the fixture comprising:

a body comprising one or more members arranged annularly about a central axis, the one or more members having a width extending axially relative the central axis and one or more tread-engaging protrusions extending radially inward relative the central axis and lengthwise in a circumferential direction.

2. The apparatus of claim 1, wherein the body forms a ring.

3. The apparatus of claim 2, wherein the ring is a continuous ring formed of elastic material.

4. The apparatus of claim 2, wherein the ring comprises a plurality of discontinuous ring segments arranged an annular arrangement.

5. The apparatus of claim 3, wherein each of the plurality of segments ring segments are secured in the annular arrangement by one or more links, each link extending between circumferentially adjacent segments.

6. The apparatus of claim 5, wherein the one or more links are elastic links allowing the ring to expand and contract.

7. The apparatus of claim 5, wherein the links are operably connected to form an annular arrangement, the links being separable from the ring segments.

8. The apparatus of claim 1, wherein the one or more tread-engaging protrusions are shaped for arrangement within a circumferentially-extending groove of the tire tread.

9. The apparatus of claim 8, wherein the one or more protrusions comprise a pair of protrusions shaped for arrangement within circumferentially-extending grooves arranged on opposing sides of a tread lug.

10. The apparatus of claim 1, wherein the body includes a pair of side protrusions configured to extend radially inward, the pair of side protrusions spaced axially by a distance, such that each of the protrusions engage an opposing side edge of a tread for forming a retreaded tire, the side edges being spaced about a width of the tire tread.

11. A method for retreading a tire carcass, the method comprising the steps of: providing a pre-cured annular tire carcass configured for receiving a tread;

arranging a tread annularly about the precured tire carcass in a desired position to form an assembled retreaded tire; and,

constraining the tread in the desired position by arranging a tread alignment fixture about an outer side of the tread.

12. The method of claim 11, wherein the step of arranging a tread annularly about the precured tire carcass includes arranging a curable joining material between the tire carcass and the tread.

13. The method of claim 11 further comprising the step of:

placing the assembled retreaded tire with the fixture arranged thereabout into a curing chamber, and

curing the retreaded tire within the curing chamber by applying pressurized and heated gases about an outer side of the assembled retreaded tire.

14. The method of claim 13 further comprising the step of inserting the assembled retreaded tire having an uncured bonding layer or an uncured tread layer into a flexible curing membrane, the membrane engaging at least a portion of the outer side of the retreaded tire and an outer side of the tread alignment fixture, wherein the step of placing the assembled retreaded tire with the fixture arranged thereabout occurs with the retreaded tire and fixture arranged within the flexible curing membrane.

15. The method of claim 11, wherein the fixture retains the tread in a desired lateral position relative the tire carcass.

16. The method of claim 11, wherein the tread alignment fixture includes a body comprising one or more members arranged annularly about a central axis, the one or more members having a width extending axially relative the central axis and one or more tread- engaging protrusions extending radially inward relative the central axis and lengthwise in a circumferential direction.

17. The method of claim 16, wherein the body forms a ring.

18. The method of claim 17, wherein the ring is a continuous ring formed of elastic material.

19. The method of claim 17, wherein the ring comprises a plurality of discontinuous ring segments arranged an annular arrangement.

20. The method of claim 18, wherein each of the plurality of segments ring segments are secured in the annular arrangement by one or more links, each link extending between circumferentially adjacent segments.