GB1597539A - Breaker reinforcing tape for tyres tyres incorporating such tape and the manufacture of such tape and tyres - Google Patents

Description

54) BREAKER REINFORCING TAPE FOR TIRES, TIRES INCORPORATING SUCH TAPE, AND THE MANUFACTURE OF SUCH TAPE AND TIRES (71) We, UNIROYAL, INC., of 1230, Avenue of the Americas, New York, NY 10020, United States of America, a Corporation organized under the laws of the State of New Jersey, do hereby declare the invention for which we pray that a patent may be granted to usn and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates generally to pneumatic tires and their manufacture, and more particularly to radial ply tires and to breaker-forming tapes (including the manufacture of such tapes) for reinforcing radial ply tire carcasses capable of being constructed in a single stage; namely, in one stage, on a single drum, in which a breaker assembly and a tread are applied to the carcass plies before the unit is converted from a substantially cylindrical condition to a substantially toroidal condition.

Radial ply tire manufacturers in increasing numbers are now attempting to build radial ply tires in a single stage to eliminate the need for the additional second stage equipment and labor typically required for such tire construction. In conventional procedures for constructing radial ply tires, there is a first stage in which the carcass or body plies are wound on a substantially cylindrical building drum and, among other things, beads are applied and anchored to the opposite end portions of the cylindrically arranged body plies. The entire unit (on first stage carcass) at that point thus has a generally cylindrical form. The cylindrical first stage carcass is then transferred to conventional second stage equipment at which the cylindrical form is shaped to a toroidal shape where breaker plies and tread are applied to it for transformation into a second stage carcass ready for vulcanization. The additional equipment and labor necessary for effecting the second stage as an independent operation is excessively costly not only with respect to equipment and labor, but also with respect to t*me and space necessary for storing the additional equipment. Clearly, the conventional two stage radial ply tire constructing operations are not entirely desirable.

In order to eliminate the second stage, radial ply tire manufacturers have been applying the breaker plies and tread to the radial ply carcass or body plies in much the same way and on equipment much the same as for building conventional bias ply tires; namely, before the cylindrical carcass is transformed into a toroid. However, such manufacturers have been compelled to use breaker plies whose substantially inextensible cords form a high bias angle (*n excess of 35 ) with a median equatorial plane of the carcass, and thus readily pantograph to accommodate the substantial expansion of the carcass into a toroid. A high bias angle provides for a satisfactory lateral stiffness *n the breaker plies, but at the cost of an unsatisfactory or insufficient amount of circumferential stiffness. An insufficient amount of circumferential stiffness will result in an unacceptably high rate of tread wear.

According to a first aspect of the present invention a breaker reinforcing tape for pneumatic tires includes a plurality of cords extending side by side longitudinally of the tape with each of said cords having a respective series of undulations therein, corresponding undulations of adjacent cords being laterally aligned with each other, a crimped strip which has continuous undulations therein that corresponds to the undulations of said cords, said crimped strip extending longitudinally of the tape with the undulations of said cords nesting respectively in the undulations of said crimped strip, said cords being anchored to said crimped strip; a flat strip which has a width substantially equal to the width of said crimped strip, said flat strip extending longitudinally of the tape and alternate ones of the apexes of the undulation of said crimped strip being anchored to said flat strip; and frangible means incorporated in and longitudinally coextensive with said flat strip for releasably reinforcing and stabilizing the tape against inadvertent longitudinal expansion that would prematurely reduce the amplitude and frequency of the undulations of said cords.

In a second aspect of the invention a method of fabricating a tire reinforcing tape which includes a plurality of side by side cords extending longitudinally of the tape and having undulations therein, and frangible means for releasably reinforcing and stabilizing the tape against inadvertent longitudinal expansion that would prematurely reduce the amplitude and frequency of the undulations of said cords, comprises crimping a strip to present continuous undulations, securing said cords to said crimped strip such that the undulations of said cords correspond to and nest in the undulations of said crimped strip, securing to said crimped strip a flat elastomeric strip having a width substantially equal to the width of said crimped strip such that alternate ones of the apexes of the undulations of said crimped strip are engaged with and anchored to said flat strip, and providing said frangible means by incorporating in, and longitudinally coextensive with, said flat strip at least one frangible, flexible element in a substantially straight condition, said element having a stretch resistance greater than the stretch resistance of said flat strip.

Desirably both the crimped strip and the flat strip are elastomeric and tacky.

The invention, in a third aspect, is also directed to a method of constructing an uncured belted pneumatic tire, which includes the steps of wrapping at least one body ply around a tire building drum, winding a multiplicity of turns of a beltforming, breaker reinforcing tape as set forth above helically around a medial portion of said body ply between the opposite edges thereof at a winding angle of substantially zero degrees relative to the mid-circumferential plane of said body ply, and wrapping a slab of tread rubber around said belt-forming structure.

In an especially advantageous arrangement, the tape winding operation is so modified that the tape windings initiate and terminate in a respective end turn that extends circularly and non-helically over a full 360 around the breaker ply and overlaps itself at least partially. After this tape formation has been completed, the carcass construction is continued by winding a treadand-sidewall slab around the tape and the breaker and body plies, the slab at least in the tread region thereof desirably having perforations to enable air entrapped therebeneath in the region of the tape to be evacuated as the entire assembly with beads applied and anchored properly to the body ply or plies is shaped into a toroidal form.

During this shaping operation. the cords in the tape are straightened out to form a substantially breaker-reinforcing structure under the tread, which provides a high degree of circumferential stiffness as well as lateral stability.

Finally, the invention also extends to an uncured belted pneumatic tire which includes a carcass composed of at least one body ply, a belt-forming structure surrounding said body ply in the medial region of said carcass, and a tread slab surrounding said belt-forming structure, said belt-forming structure comprising a tape of cords wound substantially helically around said medial region of said carcass with a multiplicity of turns having a winding angle of substantially zero degrees relative to the mid-circumferential plane of said carcass, the tape being as set forth above; and to a tire formed by curing such uncured tire.

The present invention will be more clearly understood from the following detailed description thereof when read in con junction with the accompanying drawings, in which: Fig. I is an enlarged fragmentary, perspective view of the tape of the present invention; Fig. 2 is a further enlarged, fragmentary, perspective view of the tape of the present invention from which there is absent, for purposes of illustration, the crimped strip; Fig. 3 is a side elevational view of the tape structure illustrated in Fig. 1; Fig. 4 is a cross-sectional view taken along the line 44 in Fig. 1; Fig. 5 is a cross-sectional view taken along the line 5-5 in Fig. 1; Fig. 6 is a fragmentary, cross-sectional view of the pneumatic tire carcass construction of the present invention on a carcass building drum; Fig. 7 is a schematic, fragmentary view of the carcass of the resent invention before application thereto of the tape; and Fig. 8 is a schematic view illustrating the full 360 initiating and terminating end turns of the tape of the present invention as it would be wound on a tire carcass pursuant to the method of the present invention.

Referring now to the drawings, and more particularly to Figs. 1 through 5, the present invention involves a tape denoted generally by the reference character 20. The tape 20 includes an uncured, elastomeric, crimped strip 22 and an uncured elastomeric, flat strip 24. The strips 22 and 24 may be constituted of natural and/or synthetic rubbers or rubber mixtures that can be stretched and compressed, and are compatible with building pneumatic tires. Preferably, such strips 22 and 24 are also tacky for adhering to various components used in the construction of pneumatic tires, and particularly radial ply tires.

Between the strips 22 and 24, there is interposed a plurality of crimped cords 26 extending side by side in parallel relation longitudinally along the strips. The cords 26 are substantially inextensible, and have respective, for example, sinusoidal, undulations that with regard to the cord with which they correspond are substantially coplanar, and with regard to adjacent cords are laterally aligned or "in phase" with one another.

The cords may be of any suitable metallic or non-metallic filamentary material, but a preferred material is an aromatic polyamide or aramid fiber, available commercially under the trade mark "Kevlar". As best illustrated in Fig. 3. in the preferred embodiment of the invention alternate ones of the apexes 28 of the undulations of each of the cords 26 are secured to the corresponding apexes of the crimped strip 22, whereas the other alternate ones of the apexes 30 are secured to and tightly between the crimped strip 22 and the flat strip 24.

The strips 22 and 24 are each compressible and tacky, and the cords thus can be impressed into the surfaces of the strips 22 and 24 by any convenient means, and will remain so affixed thereto. In particular, in fabricating the tape the strip 22 is crimped to present the continuous undulations, and the apexes 28 and 30 of the undulations of each of the cords 26 are then impressed into the strip 22, to rest in the tmdulations of the strip 22.

Thereafter. the flat strip 24 is pressed against the assembly of the crimped strip 22 and cords 26 only at the apexes 30 of the cord 26 and the corresponding regions of the strip 22.

It is, thus, the flat strip 24 that sustains the crimped strip 22 and cords 26 in an undulation-presenting condition. It is the tacky condition of the strips 22 and 24 and their ready compressibility and impressibility that secures the assembly as a unit.

In order to assure the integrity of the flat strip 24 against inadvertent expansion that would prematurely reduce the amplitude and frequency (number of undulations per unit length of the strip 22) of the undulations of the crimped strip 22, and particularly assume that the tape 20 is provided with a reliable length that under prescribed tensile pressure is substantially invariable, frangible means in the form, for example, of one or more thin cotton elements 32 are fixedly predisposed in parallel relation flat along the flat strip 24 as the strip 24 is applied to the assembly of the crimped strip 22 and cords 26. The cotton elements 32 have a cross-sectional size that is less than the cross-sectional size of each of the cords 26 and may, for example, tear only after being subjected to tensile load in excess of five pounds. Needless to say, the stretch resistance of the elements 32 must be greater than the stretch resistance of the strip 24.

Rather than lie between the flat strip and the crimped strip the frangible means may be embedded in the thickness of the flat strip, or may lie on the exposed surface of the flat strip.

With respect to the cords 26, it is preferred that they be provided with weakened regions such as nicks or the like to enable the cords to rupture selectively at prescribed tensile loads.

It is also preferred that such nicks or weakened regions in the cords 26 be staggered relative to one another from cord to cord so that should more than one of the cords rupture, they will not do so along the same lateral line of the tape 20. The depth of the nicks, for example, is selected to reduce the full tensile strength of each of the cords 26 to between about five percent and twenty percent of its original tensile strength.

As shown, the tape 20 is comprised of nine cords 26 and has a width of, for example, approximately 1.6 cm (5/8 inch). It will be understood, however, that other numbers of such cords 26 may be selected, as well as other tape widths, depending on the particular purpose the tape 20 is to serve and on the particular pneumatic tire components and sizes it is to be constructively arranged with.

It is contemplated, pursuant to the present invention, that the tape 20 be utilized as an outer breaker for belted, radial ply tires capable of being constructed in a single stage. In this regard, it is contemplated that the tape 20 is helically wound around a raw or uncured tire carcass such as that illustrated in Fig. 6 and denoted generally by the reference character 40. The carcass 40 is comprised of a pair of body plies 42 and 42a each reinforced with, for example, polyester cords 43 (Fig. 7), and a pair of breaker plies 44 and 44a each reinforced with, for example, glass cords 45 (Fig. 7). The body plies 42, 42a are arranged cylindrically on a carcass building drum 46 such that the parallel polyester cords 43 thereof run parallel or substantially parallel to the axis of the drum, i.e. at substantially 90 relative to a median equatorial plane of the carcass. It is well known that body plies in radial ply carcasses can deviate slightly from a true parallelism to the drum axis, and where such deviation is present the body plies are arranged so that the cords in one ply run oppositely to i.e.

cross, those in the other ply. The breaker plies 44, 44a, on the other hand, are arranged cylindrically around the body plies 42, 42a such that their respective glass cords 45 from belt to belt run oppositely of one another, and within each belt run parallel to one another at an angle relative to the median equatorial plane of the carcass in excess of 35' and preferably approximately 45 .

The cylindrical carcass 40 of the body plies 42, 42a and breaker plies 44, 44a is reinforced by the tape 20 by winding the latter helically around the outer breaker ply 44 from one edge thereof to the other. However. pursuant to a principal concept of the present invention, the tape 20 is wound around the breaker ply 44 in a preferred manner. In this regard, as best illustrated in Fig. 8, the very first turn 50 of the tape 20 is wound around the outer breaker ply 44 near or adjacent to one edge thereof entirely at zero degrees, or, more particularly, circularly and non-helically such that it extends a full 360 and then overlaps itself at least in part without straying from its zero degree pitch. Once such a partial overlap is achieved, the pitch of the tape turn locus can be altered from zero degrees into a helical path near, but slightly in excess of. zero degrees until the entire breaker ply 44 is helically covered. The last turn, however, is terminated in the same manner as the first turn is initiated. As such, the last turn 52 is effected entirely at zero degrees, circularly and non-helically, such that it extends a full 360' and then overlaps itself at least in part at the opposite edge of the breaker ply 44.

After the tape 20 is applies to the carcass 40, a pair of beads is applied and anchored to the opposite end portions of the assembly, a tread-and-sidewall slab 54, perforated at least between the opposite edges of the breaker ply 44, for example, at 55, is wound upon the assembly, and the cylindrical assembly is transformed into the shape of a torus in the curing press. As the assembly is so transformed, the glass cords 45 of the breaker plies 44, 44a pantograph slightly to accommodate the circumferential expansion of such plies, and the tape 20 is stretched taut. As the tape 20 is so stretched, the undulations of its cords 26 and of the strip 22 are completely flattened, and the frangible cotton elements are torn. Moreover, air entrapped in the crimped undulations of the tape 20 beneath the tread-and-sidewall slab 54 is forcibly discharged through the venting perforations 55 of the slab 54 during such circumferential expansion of the carcass components.

It will be understood that the amplitude and frequency of the undulations of the tape 20 is selected as a function of the elongation that the tape will undergo as the cords are transformed from their initial crimped condition on the cylindrical carcass 40 to their final straightened condition on the toroidal carcass. The amount of permitted "soft stretch" or substantially non-stressed elongation of the tape thus is the difference between the crimped cord length and the straight cord length. It is preferred, in this regard, that the inextensible cords 26 should not be physically stretched. However, since the cords are nicked periodically, should they become overstressed somewhat during the circumferential expansion of the carcass 40, such nicks will tear or stretch slightly to allow for final crown curvature or even for processing variations, or to prevent cords 26 from being pulled damagingly into abrasive engagement with the underlying glass cords 45 of the outer breaker ply 44.

The cylindrical belted, radial carcass 40, when ready for vulcanization into its final tire product condition, thus is a single stage intermediate article requiring no additional steps of construction. In the finished tire, the full 360 initiating and terminating end turns of the tape 20 prevent the intermediary helical turns thereof from causing twisting of the tire components relative to one another at the tread/road interface and thereby prevent excessive, uneven tread wear. Such end turns, therefore, stabilize the tire and prolong its useful life.

It will be understood that if it is desired to build a zero degree belted tire having no bias-angled breaker plies such as 44 and 45 around the crown region of the carcass, the belt-forming structure can be attained by winding the tape, at the small winding angle and in the manner herein described, directly onto the body plies such as 42 and 42a of the tire carcass. It will also be understood that the invention is applicable to a tire wherein the carcass has only a single body ply. with or without the breaker plies such as 44 and 45.

In any construction where breaker plies such as 44 and 45 are included, there may only be one such ply, or more than two such plies may be incorporated.

WHAT WE CLAIM IS: 1. A breaker reinforcing tape for pneumatic tires, wherein the tape includes a plurality of cords extending side by side longitudinally of the tape with each of said cords having a respective series of undulations therein, corresponding undulations of adjacent cords being laterally aligned with each other, a crimped strip which has continuous undulations therein that correspond to the undulations of said cords, said crimped strip extending longitudinally of the tape with the undulations of said cords nesting respectively in the undulations of said crimped strip, said cords being anchored.to said crimped strip; a fat strip which has a width substantially equal to the width of said crimped strip, said flat strip extending longitudinally of the tape and alternate ones of the apexes of the undulations of said crimped strip being anchored to said flat strip; and frangible means incorporated in and longitudinally coextensive with said flat strip for releasably reinforcing and stabilizing the tape against inadvertent longitudinal expansion that would prematurely reduce the amplitude and frequency of the undulations

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (33)

**WARNING** start of CLMS field may overlap end of DESC **. 42, 42a and breaker plies 44, 44a is reinforced by the tape 20 by winding the latter helically around the outer breaker ply 44 from one edge thereof to the other. However. pursuant to a principal concept of the present invention, the tape 20 is wound around the breaker ply 44 in a preferred manner. In this regard, as best illustrated in Fig. 8, the very first turn 50 of the tape 20 is wound around the outer breaker ply 44 near or adjacent to one edge thereof entirely at zero degrees, or, more particularly, circularly and non-helically such that it extends a full 360 and then overlaps itself at least in part without straying from its zero degree pitch. Once such a partial overlap is achieved, the pitch of the tape turn locus can be altered from zero degrees into a helical path near, but slightly in excess of. zero degrees until the entire breaker ply 44 is helically covered. The last turn, however, is terminated in the same manner as the first turn is initiated. As such, the last turn 52 is effected entirely at zero degrees, circularly and non-helically, such that it extends a full 360' and then overlaps itself at least in part at the opposite edge of the breaker ply 44. After the tape 20 is applies to the carcass 40, a pair of beads is applied and anchored to the opposite end portions of the assembly, a tread-and-sidewall slab 54, perforated at least between the opposite edges of the breaker ply 44, for example, at 55, is wound upon the assembly, and the cylindrical assembly is transformed into the shape of a torus in the curing press. As the assembly is so transformed, the glass cords 45 of the breaker plies 44, 44a pantograph slightly to accommodate the circumferential expansion of such plies, and the tape 20 is stretched taut. As the tape 20 is so stretched, the undulations of its cords 26 and of the strip 22 are completely flattened, and the frangible cotton elements are torn. Moreover, air entrapped in the crimped undulations of the tape 20 beneath the tread-and-sidewall slab 54 is forcibly discharged through the venting perforations 55 of the slab 54 during such circumferential expansion of the carcass components. It will be understood that the amplitude and frequency of the undulations of the tape 20 is selected as a function of the elongation that the tape will undergo as the cords are transformed from their initial crimped condition on the cylindrical carcass 40 to their final straightened condition on the toroidal carcass. The amount of permitted "soft stretch" or substantially non-stressed elongation of the tape thus is the difference between the crimped cord length and the straight cord length. It is preferred, in this regard, that the inextensible cords 26 should not be physically stretched. However, since the cords are nicked periodically, should they become overstressed somewhat during the circumferential expansion of the carcass 40, such nicks will tear or stretch slightly to allow for final crown curvature or even for processing variations, or to prevent cords 26 from being pulled damagingly into abrasive engagement with the underlying glass cords 45 of the outer breaker ply 44. The cylindrical belted, radial carcass 40, when ready for vulcanization into its final tire product condition, thus is a single stage intermediate article requiring no additional steps of construction. In the finished tire, the full 360 initiating and terminating end turns of the tape 20 prevent the intermediary helical turns thereof from causing twisting of the tire components relative to one another at the tread/road interface and thereby prevent excessive, uneven tread wear. Such end turns, therefore, stabilize the tire and prolong its useful life. It will be understood that if it is desired to build a zero degree belted tire having no bias-angled breaker plies such as 44 and 45 around the crown region of the carcass, the belt-forming structure can be attained by winding the tape, at the small winding angle and in the manner herein described, directly onto the body plies such as 42 and 42a of the tire carcass. It will also be understood that the invention is applicable to a tire wherein the carcass has only a single body ply. with or without the breaker plies such as 44 and 45. In any construction where breaker plies such as 44 and 45 are included, there may only be one such ply, or more than two such plies may be incorporated. WHAT WE CLAIM IS:

1. A breaker reinforcing tape for pneumatic tires, wherein the tape includes a plurality of cords extending side by side longitudinally of the tape with each of said cords having a respective series of undulations therein, corresponding undulations of adjacent cords being laterally aligned with each other, a crimped strip which has continuous undulations therein that correspond to the undulations of said cords, said crimped strip extending longitudinally of the tape with the undulations of said cords nesting respectively in the undulations of said crimped strip, said cords being anchored.to said crimped strip; a fat strip which has a width substantially equal to the width of said crimped strip, said flat strip extending longitudinally of the tape and alternate ones of the apexes of the undulations of said crimped strip being anchored to said flat strip; and frangible means incorporated in and longitudinally coextensive with said flat strip for releasably reinforcing and stabilizing the tape against inadvertent longitudinal expansion that would prematurely reduce the amplitude and frequency of the undulations

of said cords.

2. A breaker reinforcing tape as claimed in claim 1, in which said crimped strip is elastomeric and tacky, and said cords are anchored thereto by virtue of respective portions of said cords at the apexes of the undulations thereof engaging and being impressed into corresponding juxtaposed portions of said crimped strip at the apexes of its undulations.

3. A breaker reinforcing tape as claimed in claim 1 or claim 2 in which said flat strip is elastomeric and tacky, and said crimped strip is anchored thereto by virtue of the respective alternate ones of said apexes of the undulations of said crimped strip and the juxtaposed portions of said flat strip mutually engaging and being pressed into one another.

4. A breaker reinforcing tape as claimed in claim 3, in which said flat strip is arranged at the face of the array of cords opposite to the face along which the crimped strip extends, and said flat and said crimped strips engage and are pressed into one another at said alternate apexes of said crimped strip through the respective interposed portions of the array of cords.

5. A breaker reinforcing tape as claimed in any of the preceding claims, in which said frangible means includes at least one flexible filament having a stretch resistance that is greater than the stretch resistance of said flat strip.

6. A breaker reinforcing tape as claimed in claim 5, in which said flexible filament is interposed between said flat and crimped strips and is in a substantially straight condition.

7. A breaker reinforcing tape as claimed in claim 5 or claim 6, in which said flexible filament is constituted of cotton and has a cross-sectional size that is less than the crosssectional size of each of said cords.

8. A breaker reinforcing tape as claimed in any one of claims 5 to 7, in which the stretch resistance of said flexible filament is such that the latter will tear when subjected to a load of approximately five pounds.

9. A breaker reinforcing tape as claimed in any one of claims 1 to 8 in which said cords are constituted of aramid fiber,

10. A breaker reinforcing tape as claimed in any one of claims 1 to 9 in which said cords are each provided with at least one nick, and said nicks in adjacent ones of said cords are staggered relative to one another.

I 1. A breaker reinforcing tape for pneumatic tires, substantially as herein described and as shown in Figures 1 to 5 of the accompanying drawings.

12. A method of fabricating a tire breaker reinforcing tape which includes a plurality of side by side cords extending longitudinally of the tape and having undulations therein, and frangible means for releasably reinforcing and stabilizing the tape against inadvertent longitudinal expansion that would prematurely reduce the amplitude and frequency of the undulations of said cords, comprising crimping a strip to present continuous undulations, securing said cords to said crimped strip such that the undulitions of said cords correspond to and nest in the undulations of said crimped strip, securing to said crimped strip a flat elastomeric strip having a width substantially equal to the width of said crimped strip such that alternate ones of the apexes of the undulations of said crimped strip are engaged with and anchored to said flat strip, and providing said frangible means by incorporating in, and longitudinally coextensive with, said flat strip at least one frangible, flexible element in a substantially straight condition, said element having a stretch resistance greater than the stretch resistance of said flat strip.

13. A method as claimed in chain 12 in which said crimped strip and said flat strip are elastomeric and tacky.

14. A method as claimed in claim 12 or claim 13, and including interposing said frangible element between said crimped strip and said flat strip.

15. A method as claimed in any one of claims 12 to 14 in which said cords are secured to said crimped strip by engaging and impressing said cords at the respective apexes of the undulations thereof into corresponding portions of the apexes of the undulations of said crimped strip.

16. A method as claimed in any one of claims 12 to 15 including providing in each cord a plurality of nicks spaced from one another longitudinally of the cord, and arranging the cords so that in adjacent cords the nicks are offset relative to each other.

17. A method of fabricating a tire breaker reinforcing tape, substantially as herein described with reference to Figures 1 to 5 of the accompanying drawings.

18. An uncured belted pneumatic tire which includes a carcass composed of at least one body ply, a belt-forming structure surrounding said body ply in the medial region of said carcass, and a tread slab surrounding said belt-forming structure, said belt-forming structure comprising a tape of cords wound substantially helically around said medial region of said carcass with a multiplicity of turns having a winding angle of substantially zero degrees relative to the mid-circumferential plane of said carcass the tape being as claimed in any one of claims 1 to 10.

19. An uncured tire as claimed in claim 18 in which at least one breaker ply is secured to said body ply in the medial region of said carcass, and said tape is wound about the carcass in surrounding relation to said breaker ply.

20. An uncured tire as claimed in claim 19. in which said tape is wound with the end turns thereof disposed intermediate the opposite edges of said breaker ply.

21. An uncured tire as claimed in any one of claims 18 to 20, in which the woundon tape initiates and terminates in a respective end turn that extends circularly and nonhelically over a full 360 around said body ply and overlaps itself at least partially.

22. An uncured tire as claimed in any one of claims 18 to 21, in which said tread slab has vent perforations therein at least at locations intermediate the respective opposite end turns of said tape.

23. An uncured tire as claimed in any one of claims 18 to 22 in which said carcass comprises two body plies, and two overlapping breaker plies are secured over said body plies, each of said body and breaker plies having encapsulated therein a respective plurality of spaced, parallel reinforcing cords, the reinforcing cords of said body plies being parallel or being oppositely oriented from ply to ply and extending at substantially 90 relative to the mid-circumferential plane of the carcass, the reinforcing cords of said breaker plies being oppositely oriented from ply to ply and extending at an angle in excess of 35 relative to said mid-circumferential plane.

24. An uncured tire as claimed in claim 23, in which the reinforcing cords of said body plies are constituted of polyester, the reinforcing cords of said breaker plies are constituted of glass fiber, and said cords in said tape are constituted of aramid fiber.

25. An uncured pneumatic tire substantially as herein described with reference to the accompanying drawings.

26. A method of constructing an uncured belted pneumatic tire, which includes the steps of wrapping at least one body ply around a tire building drum, winding a multiplicity of turns of a belt-forming tape as claimed in any one of claims 1 to 11 helically around a medial portion of said body ply between the opposite edges thereof at a winding angle of substantially zero degrees relative to the mid-circumferential plane of said body ply, and wrapping a slab of tread rubber around said belt-forming structure.

27. A method as claimed in claim 26, and comprising the further step, to precede the winding of said tape around said body ply, of wrapping at least one breaker ply of reduced axial extent around said body ply, said tape winding step being performed to dispose said tape directly around said breaker ply.

28. A method as claimed in claim 27 in which said tape winding step is performed to dispose the opposite end turns of said tape intermediate the opposite edges of said breaker ply.

29. A method as claimed in any one of claims 26 to 28 in which said tape winding step is performed so that the tape windings initiate and terminate in a respective end turn that extends circularly and non-helically over a full 360 around said body ply and overlaps itself at least partially.

30. A method as claimed in any one of claims 26 to 29, in which two body plies are wound on said drum, and two breaker plies are wound about said body plies in the medial region thereof, each of said body and breaker plies having encapsulated therein a respective plurality of spaced, parallel reinforcing cords, the reinforcing cords of said body plies being parallel or being oriented oppositely from ply to ply and extending at substantially 90 relative to the mid-circumferential plane of the carcass, the reinforcing cords of said breaker plies being oriented oppositely from ply to ply and extending at an angle in excess of 35 relative to said midcircumferential plane.

31. A method as claimed in claim 30, in which the reinforcing cords of said body plies are constituted of polyester, the reinforcing cords of said breaker plies are constituted of glass fiber, and said cords in said tape are constituted of aramid fiber.

32. A method of constructing an uncured belted pneumatic tire, substantially as herein described with reference te the accompanying drawings.

33. A pneumatic tire formed by curing an uncured belted pneumatic tire according to any one of claims 18 to 25.