Abstract: A steel cord for reinforcing rubber articles comprises one wave-form or helical core steel filament and five to eight sheath steel filaments disposed around the core steel filament, the pitch Pc of the core steel filament is 3.0 dc/0.34.ltoreq.Pc.ltoreq.10.0 dc/0.34 (dc=diameter of steel core filament) and the core forming ratio Rc=Lc/dc (Lc is an amplitude of the wave or helix of the core steel filament) is within a particular range varying depending on the number of sheath steel filaments. A pneumatic tire contains a cross belt reinforced with the above-mentioned steel cords where(i) an angle .theta. formed by the reinforcing steel cords and the equatorial plane of the tire is:12.degree..ltoreq..theta..ltoreq.30.degree.(ii) a gap between any two adjacent steel cords in the same layer of the cross belt, I, is:0.5 mm.ltoreq.I.ltoreq.2.0 mm(iii) a gauge of the gum between any two facing steel cords in different layers of the cross belt, G, is:0.35 mm.ltoreq.G.ltoreq.2.0 mm.

Abstract: The radial pneumatic passenger car tire of this invention has three belt plies. The inner and outer plies are constructed essentially the same having the same cord material disposed at an angle of approximately 15 to 20 degrees. The belt reinforcing members in the inner and outer plies can be of a textile cord material or preferably are of a nylon monofilament material. The middle ply of the three belt plies has reinforcing members at an opposed cord angle to the other plies of approximately -15 to -20 degrees. The middle ply is made with reinforcing members being either of textile cords or preferably metallic cables.

Abstract: A rubber article has a body consisting of rubber and a reinforcement structure with cables embedded in the rubber body. The cables have at least one inner layer with at least one first filament wherein at least one first filament consists of a metallic alloy. The outermost layer has second filaments embedded adhesively in the rubber body. All of the first and second filaments that consist of a metallic alloy are coated with a corrosion-protective coating. The corrosion-protective coating for at least one of the first filaments consists of an intrinsically conductive polymer.

Abstract: A high elongation compact helical steel cord with a high degree of elongation at break of not less than 5% has a (1.times.n) structure comprising three or more base wires which are helically preformed at a predetermined pitch and which are twisted in the same direction and at the same pitch so that the ratio P/D of the cord diameter D to the twisting pitch P is in the range of 8-15 with the base wire preforming pitch being shorter than the cord twisting pitch. The finished cord has a helical composite structure with its elongation under a load of 35 kgf/mm.sup.2 being 0.71%-1.00% and that under a load of 70 kgf/mm.sup.2 being 1.18%-1.57%. A radial tire is reinforced with the steel cord preferably as a steel belt cord. An apparatus for making the steel cord is provided with revolving preformers on the wire introducing portion of a bunching machine such that the bunching machine is rotated in a direction reverse to the rotational direction of the revolving preformers.

Abstract: An aramid monofilament having high mechanical properties is provided. This monofilament has a slightly structured skin and resists fibrillation and abrasion. In addition, a process for the production of this monofilament is also provided. The process includes the following steps: (i) a solution of aromatic polyamide(s) is extruded as a liquid jet in a spinneret through a capillary; (ii) the jet is drawn from the capillary in a non-coagulating layer of fluid and (iii) the drawn liquid vein is introduced into a coagulating medium in order to form the monofilament, which is subsequently washed, dried and contacted with a solvent for said monofilament to produce the slightly structured skin. The aramid monofilament is characterized by the following relationships:1.7.ltoreq.Ti.ltoreq.260;50.ltoreq.D.ltoreq.480;T.gtoreq.180-D/3;Mi.gtoreq.1600;Ar>2.00; andEr>20.0 D/30.In the above relationship, Ti represents linear density in tex, D represents diameter in .mu.

Abstract: The anchoring of the carcass reinforcing elements 1 is assured by circumferential cables 2, with the interposition of a connecting rubber composition 3. The circumferential cable 2 is arranged in several turns forming one or more helices. These circumferential cables have an operational elongation rate A.sub.f =A.sub.e +A.sub.p of more than 4%. This operational elongation rate does not include the specific elongation A.sub.s of the "cable" effect. The maximum stress R.sub.m of the cable 2 is preferably more than 2000 MPa. The cables have undergone a heat treatment which has, in combination, the features of being a recovery annealing treatment and which is carried out directly on cable comprising wires previously separately covered by an adherent coating.

Abstract: A metal wire, having a steel core and being provided with a layer of cladding of a zinc/manganese alloy containing between 5% and 80% of manganese. The wire is used as a reinforcement structure for tires or other products of elastomer material. Several embodiments of a process for applying the cladding on the steel core by electrodeposition of the zinc/manganese alloy are also described.

Abstract: A tire cord which is improved in rubber penetration. The cord has at least four filaments twisted together so as to form a core and a sheath surrounding the core. The filaments change place repeatedly along the longitudinal direction of the cord such that one of the filaments forms the core in a portion, but in a different portion of the cord, the same filament forms part of the sheath.

Abstract: A steel cord for reinforcing rubber articles comprises one wave-form or helical core steel filament and five to eight sheath steel filaments disposed around the core steel filament, the pitch Pc of the core steel filament is 3.0 dc/0.34.ltoreq.Pc.ltoreq.10.0 dc/0.34 (dc=diameter of steel core filament) and the core forming ratio Rc=Lc/dc (Lc is an amplitude of the wave or helix of the core steel filament) is within a particular range varying depending on the number of sheath steel filaments. A pneumatic tire contains a cross-belt reinforced with the above-mentioned steel cords wherei) an angle .theta. formed by the reinforcing steel cords and the equatorial plane of the tire is:12.degree..ltoreq..theta..ltoreq.30.degree.(ii) a gap between any two adjacent steel cords in the same layer of the cross belt, I, is:0.5 mm.ltoreq.I.ltoreq.2.0 mm(iii) a gauge of the gum between any two facing steel cords in different layers of the cross belt, G, is:0.35 mm .ltoreq.G.ltoreq.2.0 mm.

Abstract: A polyester tire cord is produced from a polyester multi-filamentary yarn having a novel internal microstructure containing crystalline, amorphous and mesomorphous portions which are changed to a definite structure of crystalline and amorphous portions during formation of the tire cord. A polyester resin containing at least 90 mol % polyethylene terephthalate is melt-spun and solidified by quenching to produce an undrawn yarn with a birefringence of 0.03 to 0.08, which is then drawn at a total draw ratio of 1.4:1 to 2.2:1 and thermally treated and relaxed. The resulting filamentary yarn is dipped in a rubber solution to produce a tire cord which exhibits excellent dimensional stability and fatigue resistance when it has been incorporated into a rubber matrix of a tire.

Abstract: In a tire comprising two identical treads (1A) and (1B) reinforced by two own reinforcements (2A) and (2B) and separated by a connecting zone (6) formed of a groove (8) and a ring (7), the ring (7) has a curve representing the circumferential tensile load F as a function of the relative elongation .epsilon. which is non-linear, the ring (7) having for small relative elongations a circumferential tensile rigidity less than for larger relative elongations.

Abstract: The method of making a pre-adherized polyester filament yarn with adhesion properties for rubber includes applying a pre-adherizing agent to a polyester filament yarn having a boiling water shrinkage value of <20% while spinning it at not less than 3200 m/min, heat treating the pre-adherized polyester filament yarn with hot air on a bobbin for several days at from 50.degree. to 90.degree. C., and then subjecting the conditioned POY to a single drawing step in which the take-off speed is 1.7 to 2.2 times faster than the inlet speed. Impregnated tire cord made from the polyester filament yarn so treated has a tensile strength of 60 to 70 cN/tex and a tempered shrinkage test value at 190.degree. C. of less than 3.5%, an adhesive power of 18 to 25 daN to rubber, an appearance grade of 2.5-4.0 and a dimensional stability value of greater than 24,000 cN/tex.sup.2.

Abstract: A pneumatic tire which comprises a carcass turned up around bead cores and a belt comprising a ply of parallel hybrid cords disposed radially outside the carcass. Each hybrid cord comprises at least one aramid strand and at least one steel strand which are twisted together. The aramid strand is made of aramid fiber filaments twisted together, and the steel strand is made of a steel monofilament.

Abstract: A steel cord for the reinforcement of the carcass of a pneumatic radial tire comprises a central basic layer comprised of 1 to 4 steel filaments, at least one coaxial layer arranged around the central basic layer and comprised of many steel filaments in which these filaments are twisted in the same twisting direction at the same twisting pitch, and a wrap filament spirally wound around the coaxial layer in the same twisting direction.

Abstract: A fiber cord having a plurality of fiber filaments twisted together in a first direction to produce strand yarns with a primary twist and a first twist coefficient, with a plurality of the strand yarns being in turn aligned and twisted together in a second twist direction opposite to the first twist direction to produce a fiber cord with a final twist and a second twist coefficient. The second twist coefficient is between 4.0 and 7.0 and the ratio of the second twist coefficient to the first twist coefficient is at least 1.25.

Abstract: A heavy duty pneumatic tire comprises a radial carcass, and a belt comprised of at least three belt layers, in which a first belt layer contains cords inclined at a large cord angle with respect to an equatorial plane of the tire and each of a second belt layer and a third belt layer contains cords inclined at a small cord angle with respect to the equatorial plane and cords of the second and third belt layers are crossed with each other. In the tire, the first belt layer is comprised of steel cords having a 1.times.N structure (N: 2-5) and/or each of the second and third belt layers is comprised of steel cords obtained by twisting 6 sheath steel filaments each having a filament diameter of not more than 0.30 mm around a single core filament at a twisting angle of not more than 6.degree..

Abstract: A bead ring arrangement for vehicle tires in which the wire layers of the wire bundle are wound from a single wire and the wire layer at the core apex side has fewer turns than the wire layer lying beneath it.

Abstract: A pneumatic radial tire for passenger cars and heavy duty use is disclosed, which tire has a rubber coated steel cord layer in its belt portion. The cord consists of a pair of steel filaments whose preform ratio "K" is set in the range of 2.05-K.sub.1 .ltoreq.K.sub.2 <2.50-K.sub.1. Conformance to this preform ratio "K" provides filaments with periodically alternate contact and non-contact regions longitudinally of the cord.

Abstract: A metal wire having a substrate and a coating. The substrate is a steel the carbon content of which is equal to at least 0.05% and at most 0.6%, this steel having a structure comprising more than 90% work-hardened tempered martensite. The substrate is coated with a metal alloy other than steel. Method of obtaining this wire. A steel machine wire comprising 28% to 96% proeutectoid ferrite and 72% to 4% pearlite is work hardened. A hardening treatment is carried out in order to obtain a structure comprising more than 90% martensite. A depositing of metals is then effected, the wire is heated to cause the formation of an alloy and the formation of a structure comprising more than 90% tempered martensite. The wire is cooled and work hardened. This wire is used, for instance, to reinforce tires.

Abstract: A metal cord usable for the reinforcement of rubber articles is comprised of a helically formed single wire filament having a twisting angle of 75-84.5.degree. or a bundle of two twisted metal filaments each having a twisting angle of 75-84.5.degree.. Such metal cords are preferably used as a rubber reinforcement in each part of a pneumatic tire.

Abstract: A reinforcement assemblage formed at least in part of continuous monofilaments of liquid crystal organic polymer or polymers, characterized by the following features:(a) the diameter D.sub.m of the monofilaments is at least equal to 40 .mu.m and less than 400 .mu.m;(b) the tenacity T.sub.a of the assemblage is greater than 80 cN/tex;(c) the secant tensile modulus M.sub.a of the assemblage is greater than 2000 cN/tex;(d) at least one of the monofilaments is practically wound helically around an axis, the acute angle .gamma. which each monofilament makes with this axis, which is assumed rectilinear, being less than 30.degree.;(e) the twist of each monofilament on itself is less than 10 turns per meter of assemblage.Articles reinforced by these assemblages, in particular automobile tires.

Abstract: A tire cord made of a multifilament yarn of polyvinyl alcohol having a degree of polymerization of at least 1500, the yarn having a tensile strength of at least 10 g/d and an index of hot water resistance of at least 50.

Abstract: A tire cord and a tire, wherein the tire cord comprises three inner steel monofilaments (FC) having a smaller diameter (dc) and seven outer steel monofilaments (FB) having a larger diameter (db), both the diameters (dc) and (db) being in the range of 0.15 to 0.28 mm, the inner and outer steel monofilaments being twisted in the same direction but at different pitches, and an average gap of at least 0.03 mm is provided between the adjacent outer steel monofilaments. The tire is provided with the cords as reinforcements, e.g. carcass cords, belt cords and the like.

Abstract: A steel cord for the reinforcement of rubber articles comprises a central basic layer comprised of 1 to 4 steel filaments, at least one coaxial layer arranged around the central basic layer and comprised of many steel filaments in which these filaments are twisted in the same twisting direction at the same twisting pitch, and a wrap filament spirally wound around the coaxial layer in the same twisting direction.

Abstract: When polyester fiber cords having elongations under loads of 0.5 g/d and 2.25 g/d within particular ranges and a heat shrinkage (177.degree. C. 30 minutes) within a particular range are used in a carcass ply of a pneumatic radial tire, the ride comfortability, tire uniformity and tire appearance can simultaneously be improved.

Abstract: A cut resistant pneumatic tire is provided. The tire has a monofilament wire structure embedded in or under its tread or sidewall, and is used in off the road applications such as mining. The monofilament wire has a diameter of 0.4 to 1.2 mm and is made of brass plated steel. The wire may be woven or may have a spring link configuration. Two monofilament wires may be twisted together, and when two such wires are used, the total diameter is 0.8 to 1.4 mm.

Abstract: Highly durable, lightweight tires of a pneumatic radial type for passenger cars are constructed with a tread portion having on its outer peripheral surface a plurality of grooves arranged circumferentially of the tire and a belt layer formed from an array of steel cords and disposed in the tread. Each of the steel cords results from twisting a selected number of steel filaments each of specified contents of C, Si and Ni and has a specified level of tensile strength. The distance of rubber from a bottom end of each of the grooves to an outer surface of the steel cord array is defined to be of a specified range as determined cross-sectionally of the tire.

Abstract: A steel cord for reinforcing a high polymer material has a core formed by twisting three steel core filaments having a mutually equal diameter of 0.1 to 0.35 mm, and at least one sheath formed by twisting a plurality of steel sheath filaments having a mutually equal diameter of 0.1 to 0.35 mm and arranged around the core. The three core filaments are composed of one or two waving steel filaments each having waved portions apart from a longitudinal center line thereof, and an unwaving steel filament as a remainder. The clearances (T) between the waving steel filament and the unwaving steel filament are in a range of 0.15 to 0.6 times the diameter of the steel core filament. A sum total (M) of a mean void (m) between adjoining steel sheath filaments in each sheath is in a range of 5 to 35% of a sum total (N) of a mean center distance (n) between adjoining steel sheath filaments in each sheath.

Abstract: A steel cord for reinforcement of rubber products composed of two material wires of a diameter of 0.25 to 0.40 mm and a carbon content of 0.75 to 0.88 wt % which are entwisted at a twist pitch of 9.0 to 16.0 mm and in open structure, with improved fatigue resistance, flexibility and corrosion resistance.

Abstract: A metal wire for reinforcing articles made of elastomeric material, especially vehicle tires. The subject wire has a coating formed by two concentric layers of zinc-nickel or zinc-cobalt alloys, the radially inner layer of which has a zinc content greater than 90% while the radially outer layer has a nickel or cobalt content greater than 50%.

Abstract: One or more plies of reinforced elastomer, particularly two plies (10),(12) of rubber reinforced with twisted filament metallic cords (14) and more particularly a tire belt made up of the two plies (10),(12) is disclosed having cords (14) of 2.times.0.30 HT construction with opposed 23.degree. angles to the direction of reinforcement of the belt.

Abstract: A pneumatic tire with carbon fiber cord reinforcement wherein the carbon fiber cords have a round cross sectional shape and a twist per inch (TPI) of 1.2 to 1.6 turns per inch (TPI) is provided. Preferably, the carbon fiber cords are coated with an RFL or epoxy/RFL adhesive. It is also preferred that carbon fiber cords having an S twist and carbon fiber cords having a Z twist be used in the same reinforcing plies in the tire. Especially preferred is the incorporation of carbon fiber cords in a folded belt.

Abstract: A steel cord (1) for the reinforcement of rubber articles such as tires includes a core of two to four steel filaments (2) and a layer of steel filaments (3, 4) around the core. All of the filaments have a diameter between 0.15 and 0.40 mm and are twisted in the same direction and at the same pitch. The cord has over a substantial portion of its entire length cross-sections where the accumulated gaps between adjacent layer filaments are at least 0.03 mm. At least one filament of the layer has been preformed differently from the other filaments. The above structure avoids core migration.

Abstract: A steel cord comprising a number (between 3 and 27) of element steel wires tightly twisted at a regular pitch P between 5 and 20 mm in the same direction. Each wire has a diameter d between 0.1 and 0.4 mm. At least one of the wires includes a spiral portion having a spiral pitch P1 between 0.1P and 0.7P and a spiral diameter d1 between d+2/100 mm and d+2/10 mm. At least one other wire includes a straight portion. At any cross section of the cord, 1/4 through 2/3 of the wires is/are spiral and the other wire/s is/are straight. The stretch of the cord under a load of 5 kg is between 0.10 and 0.40%. A method of producing a steel cord comprises supplying a number of element steel wires, forming at least part of at least one of the wires to be spiral, and tightly twisting the wires.

Abstract: Tires of a large size for use off-the-road with super tensile reinforcement having values of at least 4655N (1046 lbs) break strength for bunched type cord.

Abstract: A pneumatic radial tire for truck and bus comprises a carcass ply containing cords arranged substantially in a radial direction of the tire and a belt superimposed about said carcass ply and comprised of plural belt layers each containing steel cords arranged at a cord angle of 5.degree.-20.degree. with respect to an equator of the tire. In this case, the steel cord for the belt layer has a two-layer structure of a core comprised of two steel filaments and a single sheath comprised of 6-8 steel filaments and satisfies the particularly relationships on filament diameter, twisting pitch, bending rigidity, tensile strength and distance between adjoining cords.

Abstract: A steel cord for reinforcement of rubber products composed of two material wires of a diameter of 0.25 to 0.40 mm and a carbon content of 0.75 to 0.88 wt % which are entwisted at a twist pitch of 9.0 to 16.0 mm and in open structure, with improved fatigue resistance, flexibility and corrosion resistance.

Abstract: A pneumatic radial tire including one or more belt layers, wherein cords are used as cords for reinforcing at least one belt layer. These cords are formed by impregnating and attaching a resin having a modulus in tension of not more than 150 kg/mm.sup.2 to bundles of cord-like fibers composed of a number of filaments having a tensile strength of not less than 15 g/d and a fineness of 1-15 deniers, an impregnated and attached amount of the filaments being in a range of 30% to 70 wt % relative to a weight of the filaments, and each of the cords has an elliptical or rectangular cross-section shape having an aspect ratio of a major axis (b)/a minor axis (a) being 1.5 to 5. Each of the bundles of the fibers are not twisted.

Abstract: A steel cord includes a core layer composed of three wires, an intermediate layer composed of seven wires, and an outer layer 12 composed of 13 wires. The space ratio of the intermediate layer is in the range from 25% to 34%. and the space ratio of the outer layer is in the range from 10% to 20%. A tire is manufactured by using the steel cord.

Abstract: This invention relates to high-speed radial tires, and more particularly to radial tires wherein the thickness ratio (Gc-Gs)/Gc, that is the ratio of the difference between the crown tread thickness Gc, which is a thickness of the tread on the equator of the tire, and the shoulder tread thickness Gs, which is a thickness of the tread of the ground contact surface at the outer edge in direction of the tire axis, to the crown tread thickness Gc is set to be 0 or more and 0.8 or less. By setting the ratio within a range of 0 to 0.8, the force Fs acting in the radial direction on the tread shoulder part, out of the total load acting to the tire, is decreased, thus, the deformation in the bead part is diminished and the permanence in the bead part can be improved. In a tire having the ratio of 0 to 0.

Abstract: Steel cables are utilized for reinforcing a wide variety of rubber articles. For instance, pneumatic tires are normally reinforced with steel tire cords. It is important for such reinforcing cables to exhibit good fatigue and corrosion resistance. It has been unexpectedly found that the fatigue and corrosion resistance of such cables can be improved by incorporating syndiotactic-1,2-polybutadiene into the interstices between the steel filaments in such cables. This invention more specifically relates to a cable for reinforcing rubber articles having improved fatigue and corrosion resistance which is comprised of a plurality of steel filaments and syndiotactic-1,2-polybutadiene, wherein the syndiotactic-1,2-polybutadiene is dispersed within interstices between said steel filaments.

Abstract: A high speed radial tire has a carcass and a belt layer, wherein; in the state of inflated with a standard internal pressure on a standard rim, a equator height H1 defined as a height of crossing point at which the inner surface of the belt layer intersects the surface of the tire equator is larger than an outer end height H2 defined as a height of the outermost end of the inner surface of the belt layer. Furthermore, a belt camber quantity H defined as a difference between the height H1 and the height H2 is set at 6% or more of the belt width W.

Abstract: An assembly (100) for the reinforcing of an article of plastic and/or rubber, characterized by the following features:(a) it comprises two adjacent concentric layers (1, 2) of filaments (10, 20), the filaments (10, 20) having their axes (O.sub.1, O.sub.2) arranged, within each of the layers, substantially on a circle (C.sub.1, C.sub.2) of radius R.sub.1, R.sub.2 ; in each layer (1, 2) the filaments (10, 20) are wound in the same direction and have the same pitch (P.sub.1, P.sub.2);(b) the layers (1, 2) have the same direction of winding;(c) R.sub.1, R.sub.2, P.sub.1, P.sub.2 are in accord with the relationship:P.sub.1 >P.sub.2 >P.sub.1 .times.[1-2(R.sub.2 -R.sub.1)/R.sub.2 ].Articles reinforced by such assemblies, for instance pneumatic tires.

Abstract: A pneumatic radial tire is disclosed, including an annular tread having a belt incorporated therein, a pair of sidewalls which extend radially inward from both ends of the annular tread and a bead portion, provided at the inner end of each sidewall, wherein the belt includes a belt ply having a plurality of belt cords in parallel arrangement, the belt cords being formed by twisting a plurality of steel filaments or two or more strands each consisting of a plurality of steel. filaments, and at least one of said steel filaments being replaced by a filament of a shape-memory alloy which, before it is twisted either as a belt cord or as a strand which forms a belt cord, has been heat set at a predetermined heat set temperature whereby the filament has a linear shape at a temperature below the heat set temperature and has a wavy shape at a temperature at or above the heat set temperature.

Abstract: A multi-layer circumferentially reinforced radial pneumatic light truck tire having a belt structure of at least two layers of 2+2x.35ST cord for Load Range E.

Abstract: A heavy duty pneumatic radial tire comprises at least one carcass ply reinforced with steel cords substantially arranged at an angle of 90.degree. with respect to an equator of the tire and wound around a bead core from inside of the tire toward outside thereof. In this tire, the steel cord is made from steel wires each having a tensile strength of 330-400 kg/mm.sup.2 and a cementite lamellar distance of 120-190 .ANG., a residual stress of whose is compression stress at a depth within a range of 1/10 to 1/5.5 of a wire diameter from the surface of the steel wire.

Abstract: A reinforcing strip, and method of making same specifically adapted for use in reinforcing plies in the belt of rubber tires. The strip comprises a number, preferably 4 to 7, of parallel wires, tightly bound together by a wrapping wire or a binder. This strip form allows to combine the advantages of steel strip, i.e. high lateral and low radial stiffness and thinner plies, with those of conventional steel cord, i.e. high tensile strength and fatigue resistance.

Abstract: The present invention relates to a brass-plated high carbon steel wire having applied thereto an aqueous zinc phosphate solution having a pH of from about 2 to about 3 and containing (1) a total of from about 28 to 32 grams per liter of phosphoric acid, (2) from about 8 to 11 grams per liter of free phosphoric acid, (3) from about 8 to 12 grams per liter of Zn.sup.+2 which may be derived from the group consisting of zinc oxide, zinc phosphate or mixtures thereof, and (4) wherein the mole ratio of total phosphoric acid to free phosphoric acid ranges from 2.5:1 to 04.0:1. In accordance with the present invention, the zinc phosphate coating on the brass-plated steel cord inhibits corrosion and adhesion of the wire to rubber after vulcanization is improved.

Abstract: A pneumatic radial tire containing a steel cord/rubber composite reinforcement structure wherein the steel cord comprises a plurality of steel filaments embedded in a rubber layer.

Abstract: A steel cord has a core strand and an outer strand. The core strand includes three wire filaments located in a core portion and each having a same diameter, and nine wires located to enclose the three wires, twisted together with the three wire filaments, and each having a diameter smaller than that of each of the three wires. The outer strand has wires located to enclose the nine wires of the core strand, twisted in a direction reverse to the twisting direction of the core strand, and having a clearance between them.