In a tire the strength of steel cord and the resilience of rubber are a successful combination. However, in some specific areas of a tire, more elongation is expected from the steel cord, while still a sufficient degree of stiffness is expected. A steel cord is presented that has these properties. The steel cord comprises two or more steel elements that are twisted together. The steel elements comprise one or more steel filaments. In total the steel cord comprises N filaments, each with a cross sectional area A. When the steel elements are individualised out of the steel cord they show a helix pitch length of L.sub.o, while a single pitch has a centre line length of S. The inventive steel cord shows a P value of at least 50 newton, wherein P=NE (A/S).sup.2. Further methods are presented to produce this steel cord.

An apparatus for producing an assembly of filamentary elements that are wound together in a helix includes a twisting device, a preforming device, and an assembling device. The twisting device is structured to twist at least first and second filamentary elements individually, such that each filamentary element is twisted separately from another filamentary element, to produce at least first and second twisted filamentary elements. The preforming device, which is arranged downstream of the twisting device, is structured to preform each of the twisted filamentary elements individually into separate preformed helixes, to produce at least first and second preformed helixes. The assembling device, which is arranged downstream of the preforming device, is structured to assemble the preformed helixes into an assembly.

[Object] A hollow stranded wire line, for manipulation, having an excellent torque transmittability is provided.

[Solution] A hollow stranded wire line 2 for manipulation is a hollow stranded wire line 2 that is advantageously used as a stranded wire line for manipulation in a medical instrument, and a side wire 4 or a side strand which is an outermost layer has a forming rate that is greater than 100% and not greater than 110%. The side wire 4 or the side strand having been formed has a spiral shape in which a flatness that is an aspect ratio obtained by a major axis being divided by a minor axis is preferably not less than 1.01 and preferably not greater than 1.10.

[Object] A manipulation rope having an excellent torque transmittability is provided.

[Solution] A manipulation rope 2 is a rope 2 that is advantageously used as a manipulation rope for a medical instrument, and includes a side wire 6 or a side strand which is an outermost layer, the side wire 6 or the side strand having a spiral shape in which a flatness that is an aspect ratio obtained by a major axis being divided by a minor axis is greater than 1.00 and not greater than 1.10. An elongation of the rope at a time when a tensile load that is 1.0% of a breaking load is applied, is preferably not less than 0.04% and preferably not greater than 0.10%.

[Object] A manipulation rope having an excellent torque transmittability is provided.

[Solution] A manipulation rope 2 is a rope 2 that is advantageously used as a manipulation rope for a medical instrument, and includes a side wire 6 or a side strand which is an outermost layer, the side wire 6 or the side strand having a forming rate that is greater than 100% and not greater than 110%. The side wire or the side strand having been formed has a spiral shape in which a flatness that is an aspect ratio obtained by a major axis being divided by a minor axis is preferably not less than 1.01 and preferably not greater than 1.10. Further, an elongation of the rope at a time when a tensile load that is 1.0% of a breaking load is applied, is preferably not less than 0.04% and preferably not greater than 0.10%.

A rubber-reinforcing steel cord embedded in a rubber product has a stranded structure including a core strand, and a plurality of sheath strands intertwined around an outer circumferential surface of the core strand; wherein a lubricant is provided between wires that constitute the core strand.

A device, which converts a reinforcing strip from being flat to being undulating, includes a transporter that guides fingers along a closed circuit, with the fingers being able to bear against a first face of the strip; a support plate that rotates about a plate axis and that supports rollers having axes parallel to the plate axis, with the rollers being able to bear against a second face of the strip; and a synchronizer that synchronizes a rotation of the support plate and a forward motion of the transporter. The closed circuit has an intersecting portion at which the synchronizer allows the fingers and the rollers to move rotationally in a common plane perpendicular to the plate axis, with the fingers and the rollers being interposed at the intersecting portion so as to cause the strip to have undulating waves that extend in the common plane.

A rubber-reinforcing steel cord embedded in a rubber product has a stranded structure including a core strand, and a plurality of sheath strands intertwined around an outer circumferential surface of the core strand; wherein a lubricant is provided between wires that constitute the core strand.

Provided is a steel cord for reinforcing rubber articles which, when applied to a belt of a tire, can attain lightweight without reducing the durability of the tire, and in particular, to a steel cord for reinforcing rubber articles in which the properties of a treat after rubberizing are excellent and a pneumatic radial tire using the same. Also provided is a steel cord for reinforcing rubber articles comprising a core formed by arranging two core filaments 1 in parallel without being twisted together, and N (2N4) sheath filaments 2 which are twisted together around the core. Letting the diameter of the core filament 1 be d1, and the diameter of the sheath filament 2 be d2, d1>d2.

A cord rubberized in situ (C). Internal layer of the cord (CT1) comprises N1 internal thread(s). External layer of the cord (CT3) comprises N3 external threads wound helically around the internal layer of the cord. Rubber composition (20) is positioned between the internal layer of the cord and the external layer of the cord, and comprises a compound of formula (I) or a salt of this compound:

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in which: each R1, R2 and R3 group represents, independently of one another, an alkylene, arylene, arylalkylene, alkylarylene or cycloalkylene group, each X.sub.1 and X.sub.2 group represents, independently of each other, COOH, CONHOH, SOOH, PO(OR)(R) or PO(OR)(OR) with R and R representing, independently of each other, hydrogen or an alkyl group, and X.sub.3 comprises at least one COOH, CONHOH, SOOH, PO(OR)(R) or PO(OR)(OR) group with R and R representing, independently of each other, hydrogen or an alkyl group.