US3900062A

US3900062A - Zero degree belted tires built with high soft stretch belt-forming tapes

Info

Publication number: US3900062A
Application number: US359118A
Authority: US
Inventors: James J Neville; Wesley Ferrell; Daniel Shichman
Original assignee: Uniroyal Inc
Current assignee: UG Licensing Services Inc
Priority date: 1971-07-08
Filing date: 1973-05-10
Publication date: 1975-08-19
Anticipated expiration: 1992-08-19

Abstract

The single-stage building of 0* belted pneumatic tires completely in flat band form on standard building drums, is disclosed. The feasibility of the process rests on the provision of the substantially inextensible metallic or non-metallic belt cords in the form of longitudinally extensible high ''''soft stretch'''' tapes. In a preferred version of the invention, the tape is composed of a plurality of cords each having formed therein a multiplicity of undulations which in any given straight length of the tape are substantially planar, the cords being disposed in side by side relation so that the planes of the undulations of each cord are generally parallel to the planes of the undulations of each adjacent cord, and the cords together with a relatively weak and frangible but only minimally undulated stabilizing yarn for the tape being secured to each other and held in their undulating state by a relative weak, chain stitch knitted, frangible stitching yarn or thread. The belt-forming structure is built by helically winding such tape circumferentially of the building drum in the medial region of the still cylindrical or flat band carcass at an angle of substantially 90* to a plane including the common axis of the carcass and the building drum, with the undulations of the cords ''''on end'''', i.e., in planes generally normal to the surface of the building drum.

Description

United States Patent [191 Neville et al.

[4 1 Aug. 19, 1975 ZERO DEGREE BELTED TIRES BUILT WllTl-I HIGH SOFT STRETCH BELT-FORMING TAPES [75] Inventors: James J. Neville, Kinnelon; Wesley Ferrell, Wayne; Daniel Shichman, Cedar Grove, all of NJ.

[73] Assignee: Uniroyal, Inc., New York, NY.

[22] Filed: May 10, 1973 [21] Appl. No.: 359,118

Related US. Application Data [62] Division of Ser. No. 160,675, July 8, 1971.

{52] US. Cl. 152/361 FP; 152/361 R; 161/57;

161/77 [51] Int. Cl. B60c 9/16 [58] Field of Search 152/356, 361 R, 361 PP,

152/361 DM, 362 CS; 161/57, 60, 77, 82, 88, 90, 92,101,142

Primary E.\'an1inerM. Henson Wood, Jr. Assistant ExaminerReinhard J. Eisenzopf Attorney, Agent, or FirmNorbert P. Holler, Esq.

[ 5 ABSTRACT The single-stage building of 0 belted pneumatic tires completely in flat band form on standard building drums, is disclosed. The feasibility of the process rests on the provision of the substantially inextensible metallic or non-metallic belt cords in the form of longitudinally extensible high soft stretch tapes, In a preferred version of the invention, the tape is composed of a plurality of cords each having formed therein a multiplicity ofundulations which in any given straight length of the tape are substantially planar, the cords being disposed in side by side relation so that the planes of the undulations of each ,rd are generally parallel to the planes of the undulations of each adjacent cord, and the cords together with a relatively weak and frangible but only minimally undulated stabilizing yarn for the tape being secured to each other and held in their undulating state by a relative weak, chain stitch knitted, frangible stitching yarn or thread. The belt-forming structure is built by helically winding such tape circumferentially of the building drum in the medial region of the still cylindrical or flat band carcass at an angle of substantially 90 to a plane including the common axis of the carcass and the building drum, with the undulations of the cords on end", i.e., in planes generally normal to the surface of the building drum.

69 Claims, 35 Drawing Figures PATENTEDAUE-I 9197s 3 900,062 SHEET 1 PATENTEB AUG'] 9 I975 SHEET PATENT AUBI 9197s 3.900.062

SHEET 5 PATENTEB AUG 1 9 \975 SHEET PATENTEU Ans-1 9 1915 SHEET PATENTED AUG! 9 I975 SHEET PATENTED AUG 1 91975 SHEET SHEET PATENTEU AUG'I 91975 ZERO DEGREE BELTED TIRES BUILT WITH HIGH SOFT STRETCH BELT-FORMING TAPES This is a division of application Ser. No. l60,675,

filed July 8, l97l.

This invention relates to belted pneumatic rubber tires, as well as to high soft stretch tapes made of substantially inextensible reinforcing cords and adapted for use in the building and protection of 0 belted tires and in particular for use in the formation of the belts of such tires.

Improving both the safety and the service life of pneumatic vehicle tires has been a goal of the tire industry for many years, with much attention being focused on such tire characteristics as tread wear, handling and road-holding ability, especially during cornering. In this regard, the desirability of producing tires with a broadened footprint (the portin of a tire tread in contact with the road surface when the tire is under load on a moving vehicle) has long been recognized.

A major step in this direction has been the advent of the belted tire, wherein a circumferentially extending belt or belt-like structure is incorporated under the tread in the crown region of the tire carcass so as to introduce a degree of restraint into the deformability of the tread. In such tires, as is well known, the belt is made of one or more pieces of generally inextensible reinforcing cord which, in any given ply, are parallel to each other and confined between ply-wide skim coats of rubber and may be oriented at a predetermined angle of up to about 35 or so to the mediam equatorial of mid-circumferential plane of the tire. Such plies are generally provided in pairs, with the cords in paired plies being oriented at equal but opposite angles to said plane.

It should be noted, by way of definition, that in this specification and the appended claims, the terms 0 belt" and 0 belted are used to describe tire constructions in which the belt cords are oriented either truly circumferentially of the tire or at an angle of substantially 0, i.e. preferably less than l but in any event no more than about 2, to that direction. The terms bias belt and bias belted" are used to describe tire construction in which the belt cords are oriented at angles greater than 2 relative to the circumferential direction. The term low angle is used to designate bias belts having a cord angle of up to about 25 to the circumferential direction, while the term high angle is used to designate bias belts having a cord angle above about 25 to the circumferential direction. The term rubber" as used herein is intended to denote both natural and synthetic rubbes or rubberlike materials, and blends thereof, specific formulations of which for a wide variety of different tire applications are well known and need not be explicitly set forth herein. The term substantially inextensible is used herein to designate the essential characteristics of filamentary reinforcing cords, which may be made of metalic materials such as steel wire or the like or of non-metallic materials such as cotton, rayon, nylon, polyester, polyvinyl alcohol, glass fiber, or the like, of being able to withstand, without substantial elongation, the tensile stresses in the belt normally encountered in service.

In the United States, at least. as far as we are aware, the production of 0 belted tires has not been entered into by the industy on a major scale, especially in the areas of passenger, truck and other on-the-road tires, because of certain manufacturing drawbacks and disadvantages which have been encountered. Principally,

this has been due to the fact that, by virtue of the inextensibility of the belt cords. the production of 0 belted tires has generally required a two-stage building opera- 5 tion, in which the beltless carcasses are built on relatively low diameter cylindrical drums and are then, either at the carcass building station or at a different station, first shaped into toroidal form on specially constructed radially expansible and axially collapsible drums before the belt and tread are applied. Representative ilustrations of the prior art 0 belted tire technology are set forth in US. Pat. Nos. 2,939,502 and No. 2,982,328. Two-stage tire building installations, however, are both complex and expensive, and their being put into general use would have entailed the intolerable economic burden of not only discarding single-stage building installations such as have heretofore been used for building beltless conventional tires completely in fiat band or cylindrical form, but of effecting major modifications of the associated tire molds and presses as well.

As is known, methods of single-stage building (as herein defined) of belted tires have of late been pro posed, but these have been directed toward the production of bias belted tires characterized by oblique orientations of the belt cords relative to the mid-circumferential plane. Representative illustrations of this technology are set forth in US. Pat. Nos. 3,486,546 and No. 3,558,389. In such methods, the belt cords are arranged in calendered cord fabric ply systems which are bias cut, and these are so applied to the carcass that the belt cords are oriented at relatively high angles to the mid-circumferential plane during the building operation and then, during the shaping of the tires in the press, pantograph down to somewhat lower angles to the mid-circumferential plane. Any such plies must, however, be spliced at their abutting or overlapped ends, which introduces a source of possible errors and defects into the tire structures. In the said US. Pat. No. 3,486,546, further, it has also been suggested that strechable cords be used in the belt plies in lieu of the conventional cords, each such cord being composed of one or more reinforcing yarns helically wrapped at a wide pitch about an elongated, precured, rubber core. In such a system, the ply splicing problem nevertheless remains, and the use of stretchable cords in the plies does not eliminate the pantographing thereof during the shaping operation. The elongation of such stretchable cords, of course, gives rise to yet another problem, in that a high degree of twist is imparted to the cords and the core is not only eliminated but remains confined between the cord turns. Moreover, in any bias belted tire, by virtue of the oblique belt cord orientations, the hoop modules of the tire in the circumferential direction is necessarily less than the maximum hoop modulus attainable with the cords oriented in the 0 direction, while at the same time the stress transfer in the shoulder regions of the tire is through rubber shear and falls off appreciably at the edges of the belt because of the cut ends of the belt cords. Thus, the performance of bias belted tires in such matters as broadened footprint, tread wear and road-holding ability tends not to be as good as that of 0 belted tires in these same areas.

It is an important object of the present invention, therefore, to provide novel and improved methods and means of building 0 belted tires entirely and economically on conventional single-stage building equipment.

More specifically, it is an important object of the present invention ot provide a novel high soft stretch reinforcing cord tape construction designed for use in building the belt-forming structures of belted tires and capable of rendering feasible the single-stage building of such tires, i.e. the building of the belt-forming structure of a 0 belted tire while the carcass of the tire is still in its original or as built state.

It is also an important object of the present invention to provide a novel and improved 0 belted tire constructions in both the raw or as built and the shaped and cured states thereof.

Generally speaking, a high soft stretch tape according to the basic aspects of the present invention comprises a continuous, longitudinally extensible strand of one or more substantially inextensible cords each having formed therein a multiplicity of undulations which in any given straight length of the tape are substantially planar, the undulations preferably being of a generally sinusoidal nature. The term soft stretch is used herein to denote the ability of the tape to be longitudinally considerably extended by the straightening of its component cord or cords without the latter being stretched. The tape is made by passing the required number of individual cords, each of which may be untreated or may have a coating of rubber or latex or other rubberadhesion promoting material pre-applied thereto, through an apparatus including an undulating and tying device by which they are both undulated and secured to each other in the desired relation, and means for controlling and synchronizing the cord feed rate into, and the tape feed rate out of, said device so as to ensure that the final tape has the desired stretch ratio (the ratio of straightened cord length to unextended tape length). The undulating and tying device preferably is a warp knitting mechanism or the like and is operated to knit a relatively weak and frangible cotton or like yarn or thread into a chain-stitch form while simultaneously therewith each cord to be included in the tape is being shuttled reciprocally across the needle path and laid into the stitches or loops of the yarn. The latter thus hold each cord in its undulating state, and where the tape includes a plurality of cords, more than one of these may also be tied to each other by the stitches. In a particularly preferred version of such a plural-cord tape, the cords are disposed side by side and laid into the stitches with the undulations of laterally adjacent cords in parallel planes and out of phase with each other. At the same time, to enhance the stability and integrity of the tape for purposes of handling, another relatively weak and frangible cotton or like thread or yarn is preferably also laid into and held by the stitches but in almost straight condition with only minimal undulation.

In accordance with a refinement of the present invention, each cord may also be provided with a multiplicity of longitudinally spaced locally weakened portions to enhance its ability to be stretched and elongated somewhat after being fully straightened out. The weakening of the cords, which may be effected mechanically, chemically, or otherwise, is preferably effected by a weakening device included in the apparatus so as to be traversed by the cords before they reach the undulating and tying device, and is carried out in such a manner as to leave them with a relatively low residual tensile strength, generally on the order of about 5 to of their full tensile strength but nevertheless sufficient to permit the cords to be fed and processed through the undulating and tying device. For any given tire to be produced, the weakening interval, i.e. the cord length betwen successive weakened portions, is selected and preset to be different than, but not equal to a regular fraction or multiple of, the ultimately intended circumferential length of a full turn of the belt cord in the finished tire.

The apparatus, in addition to the components so far described, also includes, when a weakening device is present, means for phasing the cords entering the undulating and tying device in such a manner that when they have been fashioned into a tape, the weakened portions of each cord of that tape are out of lateral alignment with the respective weakened portions of each next adjacent cord. Where a final higher cord number tape is to be made of a plurality of lower cord number tapes, the apparatus further includes, in addition to the facilities for making as many low cord number tapes as are required, means for bringing the low cord number tapes together into side by side relation after they leave the undulating and tying device, and means for causing the tapes to adhere firmly to each other so as to create the final high cord number tape. If the cords are weakened, the apparatus will also include means for phasing the respective low cord number tapes as they leave the undulating and tying device in such a manner that when they are brought together, the weakened portions of the respective proximate or facing side cords of the tapes are out of lateral alignment with each other.

The specific nature, amplitudes and frequencies or pitch lengths of the undulations of the cords will, of course, be predetermined and controlled during the tape-forming operation to impart to the ultimate tape the required high soft stretch. In general, the degree of soft stretch, i.e. the stretch ratio, of the tape will depend on the extent to which, for any given tire, the beltforming structure built up of such tape will have to expand radially from its building diameter to the final belt diameter. More particularly, the stretch ratio will then be no greater than,substantially equal-to the expansion ratio of the tire, defined as the ratio of the diameter of the final belt in the shaped tire to the mean diameter of the belt-forming structure on the building drum (or, in other words, as the ratio of the circumferential length of one full turn of the belt cord in the shaped tire to the circumferential length of one full turn of the starting tape on the building drum). Nevertheless, although the stretch ratio may be less than the expansion ratio, it is contemplated by the present invention that it will be no smaller than the expansion ratio less the elastic strain capability of the cord in the case of an unweakened cord tape, and in the case of a weakened cord tape no smaller than the expansion ratio less approximately the capability of the cord to elongate by strain, by partial untwisting, and by ultimate rupture at the weakened positions. Merely by way of example, it is found that for most standard rim size belted passenger tires which are completely built in flat band form in a single-stage building operation prior to being shaped, a tape having a stretch ratio of between about [.5 and 1.9 (50% and gives satisfactory results, but it will be understood that for certain types of tires the building operation may dictate the use of tape with a stretch ratio in the neighborhood of as little as about 1.2 (20%) while for other types the stretch ratio may have to be in the neighborhood of as much as about 4 (400%).

In the building of a raw or uncured belted tire according to the present invention, after the necessary beads, carcass plies and other conventional tire components have been assembled on the usual low diameter drum, the belt-forming structure is built up (either on the same drum or on another one of the same diameter and either at the same station or at a different one if the carcass is being built at one place and the belt and tread rubber are to be added another) by winding an appropriate amount of high soft stretch tape helically about the medial region of the still as built, e.g. cylindrical or flat band, carcass at an angle of substantially 90 to a plane including the axis of the carcass, i.e. at an angle of substantially 0 to a plane perpendicular to the said axis. The tape is preferably Wound so as to dispose the undualtions thereof on end relative to the carcass, i.e., in plane generally normal to the surface of the carcass or the drum surface. It will be understood that the tape,

once properly deposited on the carcass, will not twist or shift out of its wound-on position, and the use of a tape or plural-cord width will enable a relatively large number of cords to be applied with each turn of the tape.

The winding operation may be either unidirectional or bidirectional with reference to the axis of the building drum and is continued until the tape-constituted belt-forming structure extends over the desired width of the medial region of the carcass. The rubber tread and sidewall stocks as well as any other still missing tire components are then applied to the carcass, with any tread splices being stitched under conditions ensuring that no undesired bunching of the belt cord tape turns will occur. Thereupon, the raw or green tire in its as built form is removed from the building drum and is ready to be subjected to the final shaping and curing operations.

When a so-built 0 raw tire is radially expanded and axially contracted into its final toroidal shape (either in the press or prior to its being put thereinto), the beitforming structure defined by the wound-on tape is subjected to the same type of radial expansion. This almost at once causes the weak stabilizing and stitching threads or yarns to be broken, which then, insofar as is presently discernible, play no further part in the process or the tire (albeit remaining in the latter). Thereupon, as the expansion of the tire continues, the cords lose their undulations and are ultimately completely straightened out to define the belt.

In this combination it should be noted that whether the tire is to be cured in a segmented mold, in which case the belt expansion will be substantially completed before the mold is closed, or whether the tire is to be cured in a standard, unsegmented mold, in which case a small further expansion may take place after the mold is closed, the tape used may have a soft stretch or stretch ratio as nearly as possible exactly equal to that actually required for the full expansion. Preferably, however, the tape used will normally have a stretch ratio somewhat less than the full expansion ratio, say between about 1 and 3 percent less, so that the cords become fully straigtened and the undulations disappear therefrom shortly before the shaping operation is completed. In such a case, of course. during the final expansion of the tire, cg. upon the forcing of the tire against the mold surfaces under high internal pressure after the mold is closed. the belt cords will be subjected to fairly high tensile stresses and will stretch and elongate to the extent required. Where the cords, by virtue of their construction and the stress-strain characteristics of the cord material. can accommodate the resultant strain and elongation without exceeding their elastic limit, the fact that they are weakened will not lead to any problems. Where the cords are locally weakened, on the other hand, they will additionally have an increased ability to undergo a hard stretch" without adverse effect, i.e., they will be able to elongate either by the strain of the cord material, or by being able to untwist somewhat between the weakened portions, or by actually breaking at one or more of the locations of the various weakened portions thereof, or by a combination of these characteristics. The weakening of the cords of the tape at a multiplicity of longitudinally spaced points as described thus can be seen to provide a margin of safety, due to the presence of which a possible choice of a tape stretch ratio lower than ordinary relative to the tire expansion ratio can be tolerated and compensated for.

When a tape of multiple side by side cords wound on end is used to build the 0 belt-forming structure, the latter can be built with appreciably reduced expenditures of time and labor and the resultant belt is a plural-wind structure with the various cords in a multiple lead screw thread-like arrangement. The formation of the ultimate 0 belt is, furthermore, effected without the kind of pantographing cord movement which characterizes the known bias belted tire manufacturing operations, even though the final belt diameter in the mold is considerably greater than the starting mean diameter of the beltforming structure on the drum. At the same time, the final belt is devoid of splices, the ab sence of which leads to a greater degree of uniformity and dynamic balance in the finished tire. The belt is also devoid of circumferentially contiguous, obliquely laterally directed, cut cord ends in the shoulder regions of the tire, which would be inevitably present in any tire utilizing bias belts constituted by one or more biascut fabric plies circumferentially laid about the carcass and could become a source of weakness, e.g. ply separa' tion. Moreover, the 0 belt leads to another advantage, i.e. a maximized hoop modulus of the tire in the circumferential direction relative to the hoop modulus which a tire utilizing a bias belt would have.

It is also to be noted that where the cords of the tape constituting the belt-forming structure are locally weakened, the strength and function of the final belt in the tire are nevertheless not impaired, since the weakened portions (and breaks, if any) in adjacent cords are staggered around the circumference of the tire and are not disposed laterally adjacent one another due to their having been phased relative to each other when the tape was made. Each weakened cord portion in the belt is, in fact, laterally confined between a relatively large number of fullstrength cord sections, so that there is no continuous line of weakness created in the belt in the axial direction of the tire, i.e. transversely of the tread, and there is no appreciable diminution of stress transfer between the rubber of the tread and the belt cords. This will be true whether or not any of the cords are broken and even if all the cords are broken at all the weakened portions thereof.

The foregoing and other objects, \QllZiTZlClCflSIiCs and advantages of the present invention will be more clearly understood from the following detailed description of various aspects and facets thereof when read in conjunction with the accompanying drawings. in which:

FIG. 1 is a fragmentary elevational view. partly in section. of a high soft stretch tape according to the basic principles of the present invention and composed of a single rubber-coated cord with planar undulations, the cord being held in the undulating state by a frangible chain stitch knitted yarn;

FIG. 1a is a sectional view, on an enlarged scale, taken along the line la-la in FIG. 1;

FIG. 2 is a fragmentary elevational view, partly in section, of a similar but two-cord high soft stretch tape, with the respective sets of undulations being disposed in parallel, side by side planes and out of phase with each other;

FIG. 3 is a fragmentary, diagrammatic, perspective view of a three-cord high soft stretch tape similar to that shown in FIG. 2;

FIGS. 3a and 3b are sectional views, on enlarged scales, taken along the lines Btu-3a and 3l23b, respectively, in FIG. 3;

FIGS. 4 and 5 are fragmentary, diagrammatic, perspective views, respectively, of six-cord and ninecord high soft stretch tapes each made of an appropriate number of laterally joined three-cord tapes of the type shown in FIG. 3;

FIGS. 4a and 5a are sectional views, on an enlarged scale, taken along the lines 411-40 and 5a5a, respectively, in FIGS. 4 and 5;

FIG. 6 is a fragmentary elevational view, partly in section, of a one-cord wide high soft stretch tape formed of two cords having their respective undulations disposed in a single common plane and in nesting relation to each other;

FIG. 7 is a sectional view, on an enlarged scale, taken along the line 7-7 in FIG. 6;

FIG. 8 is a fragmentary elevational view of a fivecord wide high soft stretch tape formed of five side by side nested-cord tapes of the type shown in FIGS. 6 and FIG. 9 is a sectional view, on an enlarged scale, taken along the line 99 in FIG. 8;

FIG. 10 is a fragmentary, diagrammatic, elevational view of a one-cord wide high soft stretch tape formed of four mutually nested coplanar cords held in their undulating state by a strip of frangible sheet material;

FIG. 11 is a sectional view, on an enlarged scale, taken along the line 11-11 in FIG. 10;

FIG. 12 is a sectional view, on an enlarged scale, taken along the line 12-12 in FIG. 10 but shows a fivecord wide tape of nested-cord tapes of the type shown in FIG. 11;

FIGS. 13 and 14 are fragmentary, diagrammatic, plan views, the latter partly broken away, of a raw 0 belted tire according to the present invention in an intermediate state and in the final state of the building thereof, respectively, the 0 belt-forming structure being illustrated as constituted by a helically on end wound sixcord tape of the type shown in FIGS. 4 and 4a;

FIG. 15 is a fragmentary, partly sectional, perspective view of a 0 belted tire having a monoply belt and produced from a single-stage built raw tire including a belt-forming structure made of on end wound tape such as those shown in FIGS. 1 to 5;

FIGS. 16 and 17 are fragmentary axial sectional views of the crown regions of single-stage built 0 belted tires similar to that shown in FIG. 15 but including, respectively, a two-ply belt resulting from a beltforming structure made of one end wound tape such as those shown in FIGS. 6 to 9, and a four-ply belt resulting from a beltforming structure made of on end wound tape such as those shown in FIGS. 10 and 12;

FIG. 18 is a fragmentary, diagrammatic illustration, in perspective but not drawn to scale, of a monoply sixcord plural-wind 0 belt the starting high soft stretch tape of which utilized locally weakened cords according to one of the embodiments of the present invention, the belt being shown in full circumferential extent and as it would be after the radial expansion of the raw tire to illustrate a preferred distribution of the weakened portions of the various cords;

FIG. 18a is a graphic representation of a developed plan view of slightly more than two full turns of the belt shown in FIG. 18 and illustrates the staggering of the weakened cord portions across the width of the sixcord winding entity;

FIG. 19 is a schematic illustration of the basic methods of making high soft stretch tapes according to the present invention;

FIG. 20 is a fragmentary, partly diagrammatic, perspective illustration of an apparatus designed for the practice of one variant of the tape-forming methods represented in FIG. 19;

FIG. 21 is a fragmentary perspective illustration, on an enlarged scale, of one type of weakening device which can be utilized in the apparatus shown in FIG. 20 for locally deteriorating and weakening the cords being formed into tape;

FIGS. 22 and 22a are fragmentary sectional views, on an enlarged scale, taken along the line 2222 in FIG.

21 and illustrate the weakening device in different stages of operation;

FIG. 23 is a fragmentary elevational view, partly in section, of a weakened cord emanating from the device shown in FIG. 21;

FIG. 24 is a fragmentary perspective view, on an enlarged scale, of an undulating and tying device which can be utilized in the apparatus shown in FIG. 20 for undulating the starting code and securing them to each other in that state to form the desired tapes;

FIG. 24a is a graphic representation of the relative motions of the various tape-forming cords and the stabilizing yarn in the device shown in FIG. 24;

FIG. 25 is a fragmentary perspective view, on an enlarged scale, of a joining device utilized in the apparatus shown in FIG. 20 for combining two lower cord number tapes into one higher cord number tape;

FIG. 26 is a sectional view, on an enlarged scale, taken along line 2626 of FIG. 25; and

FIG. 27 is a sectional view, on an enlarged scale, taken along the line 27-27 in FIG. 26.

Referring now to the drawings in greater detail, FIG. 1 shows a high soft stretch tape 1 according to one aspect of the present invention, the tape being constituted by a single, undulating cord 2 shown, merely by way of example, as being composed of a substantially inextensible filamentary cord member 3 encased in an outer covering or sheath 3' of rubber. Most advantageously, the cord is held in its undulating state by a series of loops or stitches of a relatively weak thread or yarn 4, hereinafter referred to as the stitching yarn or thread, with the line of stitches extending along the longitudinal center line or axis of symmetry of the series of undulations. Preferably, the loops of the stitching yarn, which are illustrated in greatly exaggerated fashion in FIG. 1a, are shown as being parts of a single chain of stitches one wale wide formed by warp knitting the yarn with a single needle and guide bar in a 1-0/0-1 movement, the yarn being continuously lapped around the needle and the cord being laid into the loops by being shuttled back and forth across the needle path. In actuality, of course, the loops of the stitching yarn will be tighter than as shown in FIG. ia. to such an extent as to bite somewhat into the rubber coating 3.

It should be noted that the term relatively weak" as used in the foregoing context is intended to denote any thread or yarn which is made to have the strength to withstand moderate tensile forces such as might be encountered in normal handling of the tape, and yet is made to be easily frangible so as not to interfere with the straightening of the cord when the tape is subjected to relatively high forces such as might be encountered during the radial expansion and shaping of a new tire in which the tape, helically wound circumferentially about the medial region of the tire carcass, constitutes the belt-forming structure. Ordinarily, therefore, the stitching yarn will be a conventional spun staple fiber yarn or thread of cotton, rayon or the like.

The undulations of the cord 2, as shown in FIGS. l and in. which are substantially planar in any given straight length of the tape, are generally sinusoidal, i.e. they have a configuration approximating that of a regular sine wave, but within the ambit of the present invention they may have any other type of analogously repeating substantially planar configuration. eg. that of a square wave, a series of loops, etc., if desired. The soft stretch of stretch ratio of the tape is, of course, determined by the magnitude of the undulations imparted to the cord, and for any given case the particular magnitude selected will, subject to the hereinbefore described variations, depend on the degree of radial expansion or increase in circumferential dimension which the helical belt-forming structure in the tire will undergo when the latter is transformed from its as built shape to its toroidal shape. Merely by way of example, to impart a stretch ratio in the range of about 1.5 to 1.9 to a tape composed of rubber-coated rayon cord about one-sixteenth inch in diameter. the cord may be undulated to a peak to peak amplitude of about threesixteenth inch and a pitch length of about five-sixteenth inch.

FIG. 2 shows a similar high soft stretch tape la which is composed of two generally sinusoidally undulating, individually rubber-coated cords 2. The respective sets of undulations of the cords are shown as being parallel to and out of phase with each other, and the cords are held in their undulating states and tied to each other by a relatively weak stitching yarn 4 knitted in the same manner as described above in connection with the onecord tape 1, with the two cords being laid into the yarn stitches so that each loop embraces both cords at their region of intersection. (The actual arrangement in cross-section is not explicitly shown but can be readily visualized from the one-cord arrangement illustrated in FIG. ila.)

In like manner, a three-cord tape 11) is shown in FIGS. 3, 3a and 3b, with the two outer cords 2 having their undulations out of phase with those of the middle cord, and all cords being laid into the stitches of the yarn 4 during the knitting thereof as previously described, so that each loop embraces all three cords at their region of intersection. It should again be kept in mind that the exaggerated representation of the tape lb in FIG. 3b is rather idealized for the sake of clarity. In actuality, as in the case of the tape la, the stitching yarn loops will be tight enough to bite into the rubber coatings 3 of the two outer cords, as indicated in FIG. 3a, and to exert sufficient lateral forces on the portions of the cords embraced in and tied together by each stitch to squash or compact the cords somewhat. This, of course, will not effect any material change in the general parallelism and side by side relationship between the cords.

For ease of manufacture, it is preferred that the undulations of the side by side adjacent cords in any such plural-cord tape be longitudinally offset with respect to each other, most preferably in a out of phase relationship as shown for the sine wave undulations in FIGS. 2 and 3 (FIG. 2 thus may be considered in effect as being a representation of all plural-cord tapes with 180 out of phase generally sinusoidal undulations when viewed in side elevation). Nevertheless, the undulations of such side by side adjacent cords in any given plural-cord type may just as well be in lateral alignment, i.e. in phase, with each other (any such tape when viewed in side elevation would have the same appearance as the tape 1 in FIG. I), inasmuch as the dis position and functional interrelationships of the cords once they have been straightened out are entirely independent of the original locations of the undulations. In tapes of plural side by side cords with in phase undulations, the joining of the cords to each other may be achieved by other types of relatively weak means than stitching yarns or threads, such as by suitable rubber cements, thermoplastic rubber compositions, etc.

The constructions of plural-cord tapes including even greater numbers of side by side cords (not shown), i.e. four, five, six, etc., tied together into a single matrix by one stitching yarn will be readily apparent to those skilled in the art from the foregoing description. It has been found, however, that tape production and handling requirements tend to place a practical upper limit of about four or five cords on such tapes. To this end, it is contemplated by the present invention that high soft-stretch plural-cord tapes of relatively higher numbers of component cords may be made of a plurality of tapes of lesser cord numbers, with the latter tapes being cemented or otherwise adhered to each other in side by side relation. Merely by way of example, there is shown in F768. 41 and 4a a six-cord tape 1c composed of two three-cord tapes lib (FIGS. 3, 3a and 3b) cemented to one another in side by side relation, with both the lower number tapes being longitudinally so offset relative to each other as to cause the undulations of the respective adjoining side cords to be out of phase with each other. Similarly, FiGS. 5 and 5a show a nine-cord tape Id built up in a similar manner of three three-cord tapes 1b. The possible variants of this type of construction will, of course, also be readily apparent; thus, the sixcord tape it' could, for example, be made of three twocord tapes la, and, for that matter, any plural-cord tape could be made of any appropriate number of tapes having lower numbers of cords, even, for example. of onecord tapes 1.

In accordance with yet another aspect of the present invention, it is further found advantageous to incorporate in any high soft stretch tape utilizing a relatively weak stitching yarn as the tying means, an additional relatively weak thread or yarn, such as is indicated schematically at 6 in FIG. la for the one-cord tape 1 and in FIGS. 3, 3a and 3/: for the three-cord tape 11:. For the sake of clarity, no such yarn 6 has been shown in FIGS. 1 and 2. The yarn 6 is preferably of the same type and physical properties as the stitching yarn 4 but is laid into the stitches or loops of the latter in the same manner as the cords 2 themselves except with only a very small degree of waviness (in a plane parallel to those of the undulations of the cords) and while being maintained under a relatively high tension equal to about 70-80 percent of its full tensile strength. The yarn 6 thus enhances the integrity of the tape and serves as a means for stablizing the tape against premature stretching thereof and a consequent undesired straightening of the cords during handling, thereby enabling the tape to be kept under the proper degree of tension without any risk of the stitching yarn opening up or breaking either while the tape is being drawn onto a take-up roll from the tape-forming apparatus or while the tape is being drawn from such a roll for the belt-building operation. By virtue of the method of its formation, therefore, the six-cord tape (FIGS. 4 and 40) has two stabilizing yarns 6 incorporated therein, while for the same reason the nine-cord tape Id (FIGS. 5 and 511) has three stabilizing yarns 6 incorporated therein.

The present invention also contemplates the provision of high soft stretch plural-cord tapes characterized by the presence of generally sinusoidally undulating cords arranged in nesting relation with each other and secured together by a relatively weak tying means. Merely by way of example, FIGS. 6 and 7 show a tape 1e composed of two cords 2 each composed of a cord member 3 and a rubber coating 3'. the two cords being arranged in nesting relation, i.e. with each two interfitted undulations disposed in a single plane. In this embodiment, the cords are again shown as being held together in their undulating state by a relatively weak stitching yarn 4 the loops of which (not shown in plan) are formed in the same manner as described hereinbefore in connection with FIGS. la and 3/2. (The tape 1e thus, although a two-cord tape, is only one cord wide, and the actual arrangement can be visualized by imagining the presence of two longitudinally, i.e. right/left, adjacent sectioned cord portions confined in each loop shown in FIG. la.) Similarly, FIGS. 8 and 9 show a five cord wide tape If composed of five such one cord wide dual-cord components 10 cemented to each other in side by side relation and arranged with their undulations out of phase with each other. It will be understood, of course, that any nested-cord tape more than one cord wide can also be formed as a unit, by jointly undulating the respective pairs of cords and so laying them into the loops of a common stitching yarn in the same manner as described above for the cords of the tape 1/) (for example, the actual arrangement for a three cord wide nested-cord tape. not shown, can be visualized by imagining the presence of three pairs of longitudinally ie. right/left, adjacent sectioned cord portions confined in each loop shown in FIG. 3/

The nestedeord principles outlined above may also be applied to greater numbers of cords than two. Thus.

FIGS. 10 and 11 show a one cord wide highsoft-stretch tape lg composed of four generally sinusoidally undulating cords 2' arranged in nesting relation, i.e. with each four interfitted undulations disposed in a single plane. In this embodiment, the cords are illustrated as being devoid ofa rubber covering (they may, for example, be either untreated or treated in any of the ways hereinbefore referred to) and are shown as being held in their undulating state by means of a relatively weak and easily frangible strip'5 of'a thin gauzelike fabric or like sheet material to which they are secured by means of parallel rows of sewn stitches 4' of a relatively weak cotton'or like thread or yarn. The width of the strip 5 preferably will be appreciably less than the outside peak to outside peak dimension of the tape, as shown. The cords may, of course, be adhered to the strip in other ways than by sewing, as by means of a suitable cement or adhesive. This latter approach is actually to be preferred where rubber-covered cords 2 are used in the tape, since the rubber would normally tend to foul the sewing needles in short order and prevent the stitching operation from being properly carried out. As illustrated by FIG. 12, furthermore, a nested-cord tape 111 more than one cord wide and composed of a number of the tapes lg of FIGS. 10 and 11 can be readily constructed simply by adhering a plurality of such tapes to each other in side by side relation and with the planes of the respective laterally adjacent sets of undulations substantially parallel to one another (it should be kept in mind, in this connection, that FIG. 12 is a somewhat idealized representation of the tape 1/1, but although in actual practice its form may not be as precise as shown, the indicated basic relationships between the tape components will be present at all times). The undulations of each cord may, concomitantly, be either out of phase with the undulations of each next adjacent cord,

as shown, or in phase therewith (not shown).

It will, of course, be readily appreciated by those skilled in the art that when tape such as those illustrated in FIGS. 1 to 5 is used in an on end wound system to build a belt-forming structure of a raw tire, it will ordinarily produce a monoply belt in the finished tire. On the other hand, when a tape such as those illustrated in FIGS. 6 to 12 is used in an on end wound system, it will produce a multiply belt in the finished tire, without, however, requiring more than one layer of tape. More detailed reference to these aspects of the invention will be had hereinafter as the description proceeds.

All of the foregoing high soft stretch tape constructions, it will further be appreciated, may utilize either cords which are unweakened or cords which are locally weakened or deteriorated in any suitable manner at a multiplicity of longitudinally spaced locations, as indicated schematically at 3" in FIG. 23 for a cord 2, to a residual tensile strength between about 5 and 20 percent of their starting tensile strength. Wherever weakened cords are used, however, the cords of any given tape will be combined so that the weakened portions of each cord are laterally out of alignment with the weakened portions of at least each next adjacent cord and preferably also with the weakened portions of all the cords of the same tape across the entire width thereof. Further reference to these and related aspects of the present invention will also be had hereinafter as the deseription proceeds.

To illustrate the basic and presently considered best method of forming high soft stretch tapes of plural cords in side by side, parallel plane relation according to the present invention, there will now be described the formation of one such tape construction, to wit a six-cord tape such as (FIGS. 4 and 4a) from two three-cord tapes such as 11; (FIGS. 3, 3a and 3b) of locally weakened rubber-covered cords 2 (the description will, of course, apply to otherwise treated cords and even untreated cords as well). It is to be noted that although the methods and apparatus for making such tape are herein disclosed in full for purposes of completeness, they actually are the invention of J. .I. Neville and D. Shichman and are disclosed and claimed in a copending application Ser. No. 160,669 filed July 8, 1971, now US. Pat. No. 3,774,662 issued Nov. 27, 1973, entitled Production of High Soft Stretch Tapes of Reinforcing Cords for Molded Elastomeric Articles" filed of even date herewith and assigned to the same assignee as the instant application.

Referring now in particular to FIG. 19, in the tapeforming operation for this construction, the starting six cords 2, which may be considered as being in two sets of three cords each, are taken from a creel-mounted set of supply spools 7. The cords are brought into parallel side by side relation by

suitable guides

8 and 9, and then moved along parallel paths of travel straddled by and extending through an intermittently activated weakening device 10 where they are periodically jointly subjected to an appropriate deterioration or weakening action. The weakening of the cords may be achieved either by physical means (omechanical, electrical, thermal, etc.) or by chemical means (acid treatment, saponification, plasticization, etc). It will be understood. of course, that not all types of cords, depending in general on the cord construction and/or the nature of the cord material, will be able to be weakened in the same manner. Basically, however, the weakening interval, i.e. the cord length between successive weakened portions for each cord of any intended tape construction, is selected to be different than, and in particular to be either an irregular fraction or an irregular multiple of, the circumferential length of one full turn of the cord in the final belt of the ultimate tire. This will ensure a non-alignment of the weakened cord portions of the belt in the axial direction of the tire, i.e. transversely of the tread, at least in successive turns of the cord.

From the device 10, the cord paths lead coextensively around a continuously driven metering roll 11 to an idler roll 12. The metering roll 11, the operation of which is synchronized with that of the weakening device 10, has a roughened or otherwise high friction exterior surface and provides the force for drawing the cords at the desired feed rate and in a slip-free manner from the supply spools 7. The paths of the three cords of each set then diverge, in the manner indicated by the reference characters 2a-2b-2c' and 2a '2b'-2c', so that the first cords travel from the roll 12 directly to a pair of guide rolls 13, while the second and third cords travel over respective phasing rolls 14 and 15 from which they converge again to come together with the first cords at the guide rolls 13. From the latter, all the cords travel jointly to an idler roll 16 located at the entrance to an undulating and tying device 17. In this way, it will be understood. the length of the path of travel of each cord of each set of three from the roll 12 to the roll 16 is varied and adjusted relative to the length of the corresponding path traveled by each of the other cords of the same set, so that when each respective three cords reach the device 17, their originally simultaneously formed and laterally aligned weakened portions are no longer in lateral alignment with each other but are longitudinally displaced or offset with respect to each other. Concurrently therewith, two stitching yarns 4 and two stabilizing yarns 6, each of the latter tensioned to about -80 percent of its tensile strength, are fed to the device 17 from respective supply spools thereof (not shown).

In the device 17, which for this tape construction includes a warp knitting mechanism to be described in greater detail hereinafter, while two knitting needles and a pair of associated threaders are operated to knit the respective relatively weak stitching yarns 4 into two separate one wale wide chains of loops such as are shown in FIG. 3b, the three cords of each set and the associated stabilizing yarn 6 are fed individually to the location of a respective knitting needle and are jointly shuttled reciprocally thereacross, i.e. transversely of the direction of needle movement, in predetermined phased relationship to each other. With the rate of feed of the cords properly controlled, therefore, in a manner which will become clear presently, each three cords and the stabilizing yarn therefor are laid in a generally sinusoidally undulating form, of appropriately large amplitude in the case of the cords, and in side by side relation with each other across the path of movement of the associated needle and into the respective loops formed thereby, so as to be embraced at their crossover portions by the stitching yarn and thus secured and locked together into a three cord tape 18. The amplitude of the shuttling movement of the stabilizing yarn is, at the same time, very limited, so that in the final tape the stabilizing yarn is almost straight and provides the integrity, i.e. resistance to premature elongation, needed to permit further handling and processing of the tape without any diminution of its prescribed stretch ratio. Preferably, the cord shuttling is so carried out that the undulations of each cord of each tape are out of phase or lateral alignment with the undulations of each next adjacent cord.

The two three-cord tapes 18 so formed are drawn away from the undulating and tying device 17 by a second continuously driven metering roll 19 disposed in termediate a pair of idler rolls 20 and 20 over which the tape is passed. The metering roll 19, like the roll 11, has a high friction exterior surface to provide for a slipfree drawing of the tapes 18 from the device 17, and its operation is synchronized with that of the metering roll 11 and the device 17. The system thus enables the amplitudes of the undulations and thereby the stretch ratio or soft stretch of each of the three-cord tapes 18 to be accurately controlled. From the idler roll 20, the paths of travel of the two three-cord tapes first diverge and then reconverge, in the manner indicated by the reference characters 18a and 1817, one tape traveling over a phasing roll 21 and thence to an idler roll 22, and the other tape traveling directly to the roll 22. In this way, the length of the path of travel of one of the three-cord tapes is varied and adjusted relative to the length of the path of travel of the other, so that when the tapes come together again at the roll 22, the two sets of staggered weakened portions are no longer in lateral alignment with each other but are longitudinally displaced or offset with respect to each other.

From the roll 22, the paths of travel of the two tapes 18 go under a guide roll 23 and then are straddled by and extend through a joining device 24 where a liquid cement or adhesive compatible with the rubber covering 3' of the cords is applied to the facing sides of the tapes and the latter are squeezed together and caused to adhere to each other to form a six-cord tape 25. The latter is then wound onto a suitable driven take-up spool or roll 26, its path of travel extending through and being straddled by a tensioning device 27 which is operable to control the driving of the take-up roll 26 so as to maintain the tape under a controlled tension.

A representative form of an apparatus A designed for the practice of the method of making such a six-cord tape is illustrated in FIG. 20. The apparatus, which for the sake of clarity is shown without its framework and without any indication of the passage of the cords, yarns and tapes therethrough, includes (see also FIG. 19) a comr on drive means 28 for all the synchronized components Eh. i.e. the weakening device 10, the metering rolls 11 and 19, the undulating and tying device 17 and the joining device 24, and a secondary drive means 29 for the take-up roll 26. The main drive means comprises an electric motor 38 driving a sprocket 39 which is connected by a chain 40 to a sprocket 41. The latter is connected via a clutch 42 to a main drive shaft 43 which carries a bevel gear 44 that is in meshing engagement with a bevel gear 45 mounted on a transverse auxiliary drive shaft 46.

The shaft 46 carries a sprocket 47 which is connected by a chain 48 to a sprocket 49 mounted on a shaft 49a connected via an adjustable reducing mechanism 50 to a shaft 510 carrying a large spur gear 51. The latter is in mesh with another spur gear 52 mounted on the shaft 53 of the metering roll 11. The shaft 53 further carries a smaller spur gear 54 which is in mesh with another spur gear 55 drivingly connected to an intermittently actuatable control switch mechanism 56, e.g. a camactuatable solenoid switch, operatively connected, as indicated schematically by the line 57, to the control or operating system 58 of the weakening device 10. It will be apparent, therefore, that the drive train so far described is operable to rotate the metering roll 1 1 at any desired preselected speed for the purpose of controlling the feed rate of the starting cords through the weakening device and into the undulating and tying device, and concurrently to cause the weakening device to be repeatedly activated at time intervals corresponding to the passage of predetermined lengths of the cords through said device.

The shaft 53 still further carries a sprocket 59 connected by a chain 60 to a sprocket 61 mounted on a shaft 62. Also mounted on the latter is a spur gear 63 which is drivingly connected via a pinion 64 with another spur gear 65 mounted on the shaft 66 of the metering roll 19. The shaft 66 further carries a sprocket 67 connected by a chain 68 to a sprocket 69 mounted on the shaft 70 of the guide roll 23. A spur gear 71 also carried by the shaft 70 is in mesh with another spur gear 72 mounted on a shaft 73 coaxially with a sprocket 74 which is connected by a chain 75 with a sprocket 76 constituting the driving element of the joining device 24. It will be apparent, therefore, that the drive train just described is operable to rotate the metering roll 19 at any desired preselected speed for the purpose of controlling the feed rate of the thrashed three-cord tapes out of the undulating and tying device 17, and that the setting of the speed of the roll 19 relative to that of the metering roll 11 controls the stretch ratio or soft stretch imparted to the three-cord tapes. Concurrently, the said drive train serves to operate certain rotary elements of the joining device 24 during the uniting of the two tapes into the final six-cord tape form.

The secondary drive means 29 comprises an electric motor 77 driving a sprocket 78 which is connected by a chain 79 to a sprocket 80 secured to a shaft 80a adapted to support the take-up roll or spool 26. The motor 77, which also drives (in a manner not shown) a reciprocating traversing guide 81 through the intermediary of a ratchet shaft 81a, is electrically tied in (in a manner not shown) with the motor 38 so as to be deenergized and bring the take-up operation to a halt whenever the operation of the motor 38, and thus the tape formation, is interrupted for any reason. The motor 77 is, however, also arranged to be independently stopped and started by the operation of the tension control device 27. Merely by way of example, the latter is shown as comprising a pair of upper, coplanar idler rollers 82 and 83 journaled on spaced, parallel axes, and an intermediate, lower gravity or floating tensioning roller 84 coplanar with the rollers 82 and 83 and journaled in a bushing 85 mounted for vertical sliding movement along an upright rod 86. The arrangement is such that the finished tape leaving the joining device 24 is passed in sequence over the roller 82, under the roller 84 and over the roller 83. The roller 84 thus is effectively supported by the festooned tape. At a pair of vertically spaced points along the path of travel of, and in position to be activated by, the roller 84 or an adjunct thereof are provided two

limit switches

87 and 88 which are connected into the circuit of the motor 77 in a manner not explicitly shown but indicated schematically by the

lines

89 and 90, the switch 87 being operable to stop the motor 77 when the roller 84 reaches the upper limit of its travel, and the switch 88 being operable to start the motor 77 when the roller 84 reaches the bottom limit of its travel.

It will be understood, therefore, that before the winding of a finished tape 25 onto the take-up roll 26 can be begun, the festoon of the tape will have to be long enough to dispose the tensioning roller 84 at the bottom end of its vertical travel path. With the motor 77 thus started, the tape is drawn out of the tension control device 27 at a slightly faster linear speed than the speed at which it is being fed thereinto from the joining device 24. Consequently, as the tape is wound onto the roll 26, the festoon of the tape between the rollers 82 and 83 starts to become shorter. If this were to continue unchecked, the tension on the tape would begin to vary significantly, i.e. to increase rapidly and continuously, as soon as the festoon had completely disappeared, which would be highly inimical to the ultimate production of uniform tires. This potential defect is avoided by the fact that well before the festoon of the tape can disappear, the tensioning roller 84 riding up in the rising bottom end of the festoon reaches the switch 87 and activates the same to stop the motor 77 and the take-up operation. Since more tape is continually being produced, however, the festoon then again begins to lengthen, which continues until the now downwardly traveling tensioning roller reaches the switch 88 and activates the same to restart the motor

Claims

1. A 0* belted tire, comprising: A. a toroidal carcass; B. a rubber tread extending from one shoulder of the tire to the other in surrounding relation to the crown region of said carcass; and C. a 0* belt disposed beneath said tread and circumferentially of said carcass; D. said belt being constituted of 1. a plurality of reinforcing cords 2. extending as a unit in a substantially straight condition helically circumferentially of said carcass 3. for at least a plurality of full turns 4. at an angle of substantially 0* to the mid-circumferential plane of said carcass, 5. at least two of said plurality of said cords in each turn thereof in said belt being disposed in side by side relation to one another widthwise of said belt and thereby being arranged in a multiple lead screw thread-like formation over the width of said belt, and E. each of said cords being locally weakened at a multiplicity of longitudinally spaced portions thereof, 1. said weakened portions of each cord being out of lateral alignment with the weakened portions of at least each next adjacent cord, and 2. the extent of weakening of each cord being sufficient to reduce the tensile strength thereof at each of said weakened portions to between about 5 percent and about 20 percent of its full tensile strength.

2. extending as a unit in a substantially straight condition helically circumferentially of said carcass

2. having in the medial region thereof a diameter which is substantially smaller than the corresponding diameter of said toroidal carcass in the crown region thereof; and B. a 0* belt-forming structure disposed within the confines of said medial region of said as built carcass; C. said belt-forming structure being constituted of

2. helically wound circumferentially of said as built carcass

2. helically wound circumferentially of said flat band carcass

2. A tire according to claim 1, wherein all of said plurality of said cords in each turn thereof in said belt are disposed in side by side relation to one another widthwise of said belt.

2. the extent of weakening of each cord being sufficient to reduce the tensile strength thereof at each of said weakened portions to between about 5 percent and about 20 percent of its full tensile strength.

2. a generally cylindrical body portion of at least one ply of rubberized tire cord fabric a. anchored at the opposite marginal regions thereof to said bead rings, respectively, and b. having a relatively low diameter intermediate said bead rings,

3. said body portion being constructed to enable said flat band carcass to be shaped into a toroidal carcass by a radial expansion of the medial region of said flat band carcass to a relatively high diameter and by a concurrent axial contraction of said bead rings toward one another; C. an outer covering of tread rubber circumferentially surroundIng said flat band carcass and overlying said medial region of the latter; and D. a belt-forming structure disposed beneath said tread rubber and within the confines of said medial region of said flat band carcass; E. said belt-forming structure being constituted of

3. A tire according to claim 1, wherein at least two additional ones of said plurality of said cords in each turn thereof in said belt are disposed in side by side relation to one another widthwise of said belt and are thereby arranged in a respective multiple lead screw thread-like formation over the width of said belt, the locus of said additional cords with reference to the axis of said carcass being radially outwardly relative to the locus of said first-named cords to provide a second ply of helically circumferentially extending 0* oriented cords in said belt.

3. for at least a plurality of full turns

4. at an angle of substantially 0* to the mid-circumferential plane of said carcass,

4. at an angle of substantially 90* to a plane including the axis of said as built carcass;

4. at an angle of substantially 90* to a plane including the axis of said flat band carcass;

4. A tire according to claim 1, wherein said plurality of said cords includes a plurality of sets of at least two cords each, the respective cords of each set being disposed in side by side relation to one another widthwise of said belt and thereby being arranged in a respective multiple lead screw thread-like formation over the width of said belt, and the respective loci of said sets of cords with reference to the axis of said carcass being radially outwardly of each other to provide a like numbered plurality of plies of helically circumferentially extending 0* oriented cords in said belt.

5. A tire according to claim 1, wherein the spacing of successive weakened portions in each cord is greater than the circumferential length of one full turn of that cord in said belt.

5. said tape being constituted of a. a plurality of reinforcing cords i. each having a multiplicity of generally sinusoidal undulations therein ii. which in any given straight length of said tape are substantially planar iii. and enable said tape to be elongated, without any stretching of said cords, by straightening of the latter to remove said undulations therefrom, iv. said cords being located in side by side relation to one another with the plane of each undulation of each cord substantially parallel to the plane of the laterally adjacent undulation of each next adjacent cord and substantially perpendicular to the surface of said flat band carcass, and v. said undulations of each cord being out of phase with the undulations of each next adjacent cord; b. a relatively weak, frangible stitching yarn warp-knitted in a 1-0/0-1 pattern into a chain stitch formation of loops coextensive with the length of said tape, each of said loops embracing at said undulations a respective laid-in set of intersecting cord portions of said tape, said stitching yarn being operable i. to hold said cords in the undulating state thereof and against straightening under moderate forces such as are applied to said tape during normal handling thereof and the building of said belt-forming structure, ii. but to yield and permit such cords to straighten out under appreciably higher forces such as are applied to said tape when said belt-forming structure composed thereof and said flat band carcass undergo a radial expansion during shaping; and c. at least one frangible stabilizing yarn extending longitudinally of the tape in an almost straight condition, respective portions of said stabilizing yarn being embraced by said loops jointly with the adjacent ones of said intersecting cord portions, the strength of said stabilizing yarn being sufficient to prevent a premature opening of said loops under said moderate forces but insufficient to withstand said higher forces; d. the magnitude of said undulations of said cord being predetermined to provide a tape stretch ratio, defined as the ratio of the length of a given one of said cords when fully straight to the length of said tape when said cords are undulated, which is no greater than substantially equal to the expansion ratio of the tire, defined as the ratio of said high diameter to said low diameter.

5. at least two of said plurality of said cords in each turn thereof in said belt being disposed in side by side relation to one another widthwise of said belt and thereby being arranged in a multiple lead screw thread-like formation over the width of said belt, and E. each of said cords being locally weakened at a multiplicity of longitudinally spaced portions thereof,

5. said tape being constituted of a. a plurality of reinforcing cords arranged in side by side relation to one another widthwise of said belt-forming structure and each i. having a multiplicity of undulations therein ii. which in any given straight length of said tape are substantially planar iii. and enable said tape to be elongated, without any stretching of said cords, by straightening of the latter to remove said undulations therefrom, iv. the plane of each undulation of each such cord being substantially parallel to the plane of the corresponding undulation of each next adjacent cord, and v. said undulations of each cord being out of lateral alignment with the undulations of each next adjacent cord; and b. relatively weak tying means acting on said cords and releasably holding the same in the undulating state thereof, said tying means being constructed i. to hold said cords against straightening under moderate forces such as are applied to said tape during normal handling thereof and the building of said belt-forming structure, ii. but to yield and permit said cords to straighten out under appreciably higher forces such as are applied to said tape when said belt-forming structure composed thereof and said as built carcass undergo a radial expansion during shaping; c. the magnitude of said undulations of said cords being predetermined to provide a tape stretch ratio, defined as the ratio of the length of each of said cords when fully straight to the length of said tape when said cords are undulated, which is no greater than substantially equal to the expansion ratio of the tire, defined as the ratio of said diameter of said toroidal carcass to said diameter of said as built carcass.

6. A tire according to claim 5, wherein said spacing of successive weakened portions in each cord exceeds said circumferential length of said one full turn thereof by an amount to an arc length of about 5* to about 25* of said belt.

7. A tire according to claim 1, wherein the spacing of successive weakened portions in each cord is an irregular fraction of the circumferential length of one full turn of that cord in said belt.

8. A tire according to claim 1, wherein the spacing of successive weakened portions in each cord is an irregular multiple of the circumferential length of one full turn of that cord in said belt.

9. A tire according to claim 1, wherein at least one of said cords is broken at at least one of said weakened portions thereof.

10. A tire according to claim 1, wherein said carcass comprises at least one ply of tire cords, the individual tire cords in at least said one ply being substantially parallel to each other and within the confines of said crown region of said carcass being oriented at an angle of between about 25* and 90* to the midcircumferential plane of said carcass.

11. A tire according to claim 10, wherein the carcass cord angle is between about 25* and about 45*.

12. A tire according to claim 11, wherein the carcass cord angle is between about 30* and about 35*.

13. A tire according to claim 10, wherein the carcass cord angle is between about 50* and about 75*.

14. A tire according to claim 13, wherein the carcass cord angle is between about 65* and about 70*.

15. A tire according to claim 10, wherein the carcass cord angle is between about 80* and 90*.

16. A tire according to claim 15, wherein the carcass cord angle is between about 83* and about 87*.

17. A tire according to claim 15, wherein the carcass cord angle is 90*.

18. A tire according to claim 1, the respective end region of said plurality of said cords in the outermost turn thereof at at least one lateral edge of said belt being effectively skived across its width at an angle of between about 3* and about 30* to the longitudinal dimension of said plurality of said cords, the direction of the skive being such as to provide the shortest cord length closest to the respective proximate shoulder of the tire.

19. A tire according to claim 18, wherein said skive is approximated by a step-off formation of said plurality of said cords at said end region thereof.

20. A tire according to claim 1, wherein the spacing of said weakened portions from one another along each cord in said belt is equal to at least the stress transfer length of that cord defined as the length thereof over which the adhesion of the surrounding rubber to the cord in the fully molded tire is equal to the breaking strength of the cord.

21. A tire according to claim 20, wherein said spacing of said weakened portions in each cord is greater than the circumferential length of one full turn of that cord in said belt.

22. A tire according to claim 21, wherein said spacing of said weakened portions in each cord exceeds circumferential length of said one full turn thereof by an amount equal to an arc length of about 5* to about 25* of said belt.

23. A tire according to claim 1, wherein the tension component of each of said cords is made of a material selected from the group consisting of metallic and non-metallic fibers.

24. A tire according to claim 23, wherein said cord tension component material is rayon.

25. A tape according to claim 23, wherein said cord tension component material is glass.

26. A tape according to claim 23, wherein said cord tension component material is metal wire.

27. A tape according to claim 23, wherein said cord tension component material is nylon.

28. A tape according to claim 23, wherein said cord tension component material is polyester.

29. A raw 0* belted tire, comprising: A. a carcass in the as built form thereof, said as built carcass

30. A raw tire according to claim 29, wherein said stretch ratio of said tape is between about 1.2 and about 4.

31. A raw tire according to claim 29, wherein said stretch ratio of said tape is between about 1.5 and about 1.9.

32. A raw tire according to claim 29, said tape constituting said belt-forming structure being wound so as to dispose said cords with said undulations thereof standing on end with reference to the surface of said as built carcass.

33. A raw tire according to claim 29, said tape constituting said belt-forming structure being wound so as to dispose said cords with said undulations thereof lying flat with reference to the surface of said as built carcass.

34. A raw tire according to claim 29, wherein the respective end region of said tape in the outermost turn thereof at at least one lateral edge of said beltforming structure is effectively skived across its width at an angle of between about 3* and about 30* to the longitudinal dimension of said tape, the direction of the skive being such as to provide the shortest cord length closest to the proximate axial end or bead region of said as built carcass.

35. A raw tire according to claim 34, wherein said skive is approximated by a step-off formation of said tape at said end region thereof.

36. A raw tire according to claim 29, Wherein said tying means is secured to all of said cords for holding them in their respective undulating states and binding them to each other.

37. A raw tire according to claim 36, said tying means comprising a frangible stitching yarn defining a series of loops coextensive with the length of said tape, each of said loops embracing a respective set of laterally adjacent portions of said cords at said undulations.

38. A raw tire according to claim 36, wherein said undulations of said cords constituting said tape are generally sinusoidal, said tying means comprising a frangible stitching yarn warp-knitted in a 1-0/0-1 pattern into a chain stitch formation of loops coextensive with the length of said tape, each of said loops embracing a respective laid-in set of laterally adjacent portions of said cords at said undulations, and said tape further comprising a frangible stabilizing yarn extending londitudinally of said tape in an almost straight condition, respective portions of said stabilizing yarn being embraced by said loops jointly with the laterally adjacent portions of said cords, the strength of said stabilizing yarn being sufficient to prevent a premature opening of said loops under said moderate forces but insufficient to withstand said higher forces.

39. A raw tire according to claim 38, wherein said undulations of each cord are out of phase with the undulations of each next adjacent cord.

40. A raw tire according to claim 29, wherein said plurality of said cords includes a plurality of sets of at least two side by side undulating cords each, and said tape comprises a respective tying means for each of said sets of cords and additional tying means securing said sets of cords to each other in side by side relation.

41. A raw tire according to claim 40, wherein each of said respective tying means comprises a frangible stitching yarn defining a series of loops coextensive with the length of said tape, each of said loops embracing a respective set of laterally adjacent portions of the respective set of said cords at said undulations thereof, and at least one of each two adjacent sets of said cords being provided on the abutting side cord thereof with a coating of a tacky substance, constituting said additional tying means, to enable said sets of said cords to adhere to each other.

42. A raw tire according to claim 40, wherein said undulations of said cords constituting said tape are generally sinusoidal, each of said respective tying means comprising a frangible stitching yarn warp-knitted in a 1-0/0-1 pattern into a chain stitch formation of loops coextensive with the length of said tape, each of said loops embracing a respective laid-in set of laterally adjacent portions of the respective set of said cords at said undulations thereof, and said tape further comprising a plurality of frangible stabilizing yarns extending londitudinally of said tape in an almost straight condition and each associated with a respective one of said sets of said cords, respective portions of each of said stabilizing yarns being embraced by said loops of the associated stitching yarn jointly with the laterally adjacent portions of said cords of the respective set thereof, the strength of said stabilizing yarns being sufficient to prevent a premature opening of said loops under said moderate forces but insufficient to withstand said higher forces, and at least one of each two adjacent sets of said cords being provided on the abutting side cord thereof with a coating of a tacky substance, constituting said additional tying means, to enable said sets of said cords to adhere to each other.

43. A raw tire according to claim 42, said undulations of each cord of each of said sets thereof being out of phase with the undulations of each next adjacent cord of the same set, and said undulations of the two abutting side cords of each two adjacent sets of said cords being out of phase with each other.

44. A raw tire according to claim 43, each of said coRds being at full strength throughout its length, and said stretch ratio of said tape additionally being no smaller than said expansion ratio less the elastic strain capability of said cords.

45. A raw tire according to claim 43, each of said cords being locally weakened at a multiplicity of longitudinally spaced portions thereof, said weakened portions of each cord being out of lateral alignment with the weakened portions of at least each next adjacent cord, and said stretch ratio of said tape additionally being no smaller than said expansion ratio less approximately the capability of said cords to elongate by strain, by partial untwisting, and by rupture at said weakened portions.

46. A raw tire according to claim 45, wherein the extent of weakening of each cord is sufficient to reduce the tensile strength thereof at each of said weakened portions to between about 5% and about 20% of its full tensile strength.

47. A raw tire according to claim 45, each of said cords being provided with a plurality of nicks spaced from each other along the respective cord, each of said nicks in each cord constituting a respective one of said weakened portions thereof.

48. A raw tire according to claim 47, wherein the depths of said nicks are sufficient to reduce the tensile strength of each cord at each of the nicked portions thereof to between about 5 percent and about 20 percent of its full tensile strength.

49. A raw tire according to claim 47, wherein the spacing of adjacent nicks from one another in each cord is equal to at least the stress transfer length of the respective cord, defined as the length thereof over which the adhesion of the surrounding elastomer material to the cord in the fully molded tire is equal to the breaking strength of the cord.

50. A raw tire according to claim 47, wherein the spacing of successive nicks from one another in each cord is greater than will be the circumferential length of one full turn of that cord in the ultimate belt to be formed when said as built carcass is shaped into said toroidal carcass.

51. A raw tire according to claim 50, wherein said spacing of successive nicks in each cord exceeds said circumferential length of said one full turn thereof in the ultimate belt by an amount equal to an arc length of about 5* to about 25* of said ultimate belt.

52. A raw tire according to claim 47, wherein the spacing of successive nicks from one another in each cord is an irregular fraction of what will be the circumferential length of one full turn of that cord in the ultimate belt to be formed when said as built carcass is shaped into said toroidal carcass.

53. A raw tire according to claim 47, wherein the spacing of successive nicks from one another in each cord is an irregular multiple of what will be the circumferential length of one full turn of that cord in the ultimate belt to be formed when said as built carcass is shaped into said toroidal carcass.

54. A raw tire according to claim 29, wherein each of said side by side cords is further disposed in nesting relation with at least one additional identically undulating cord.

55. A single-stage built raw 0* belted tire, comprising: A. a generally cylindrical, flat band carcass; B. said flat carcass including

56. A raw tire according to claim 55, wherein said plurality of said cords includes a plurality of sets of at least two side by side undulating cords each, a respective frangible stitching yarn and a respective frangible stabilizing yarn for each of said sets of cords, and a coating of a tacky substance on the abutting side cord of at least one of each two adjacent sets of said cords, to enable said sets of said cords to adhere to each other.

57. A raw tire according to claim 56, each of said cords being at full strength throughout its length, and said stretch ratio of said tape additionally being no smaller than said expansion ratio less the elastic strain capability of said cords.

58. A raw tire according to claim 56, each of said cords being locally weakened at a multiplicity of longitudinally spaced portions thereof, said weakened portions of each cord being out of lateral alignment with the weakened portions of at least each next adjacent cord, and said stretch ratio of said tape additionAlly being no smaller than said expansion ratio less approximately the capability of said cords to elongate by strain, by partial untwisting, and by rupture at said weakened portions.

59. A raw tire according to claim 58, wherein the extent of weakening of each cord is sufficient to reduce the tensile strength thereof at each of said weakened portions to between about 5 percent and about 20 percent of its full tensile strength.

60. A raw tire according to claim 58, wherein each of said cords is provided with a multiplicity of nicks each constituting a respective one of said weakened portions.

61. A raw tire according to claim 60, wherein the depths of said nicks are sufficient to reduce the tensile strength of each of said cords at each of the nicked portions thereof to between about 5 percent and about 20 percent of its full tensile strength.

62. A raw tire according to claim 56, wherein the tension component of each of said cords is made of a material selected from the group consisting of metallic and non-metallic fibers.

63. A raw tire according to claim 62, wherein said cord tension component material is rayon.

64. A raw tire according to claim 62, wherein said cord tension component material is glass.

65. A raw tire according to claim 62, wherein said cord tension component material is metal wire.

66. A raw tire according to claim 62, wherein said cord tension component material is nylon.

67. A raw tire according to claim 62, wherein said cord tension component material is polyester.

68. a raw tire according to claim 55, wherein the respective end regions of the two laterally outermost turns of said tape constituting said belt-forming structure at the lateral edges of the latter are effectively skived across the width of said tape at an angle of between about 3* and about 30* to the longitudinal dimension of said tape.

69. A tire according to claim 68, wherein said skive is approximated in said belt-forming structure by a step-off formation of said tape such that the laterally outermost cords terminate before the laterally inwardmost cords at each end of said tape.