Bridgestone Corporation

Bridgestone Metalpha Corporation

Eiji Kudo

Masahiro Yoshida

Takashi Kinoshita

Yuichi Kimura

Yoshiki Mizuta

Shogo Ueda

Takahiro Yamada

Yukio Sangawa

Takaya Yamanaka

A steel cord for reinforcement of rubber articles, whose cord strength is enhanced by preventing occurrence of preceding break of the outermost layer filaments in the steel cord having a multi-twisted structure, and a pneumatic tire using it as a reinforcing material are provided. In a steel cord for reinforcement of rubber articles having a multi-twisted structure in which a plurality of strands are twisted together, which strands have a layered twisted structure in which a plurality of steel filaments are twisted together, dc/ds, which represents the ratio between dc, the diameter of outermost layer sheath filaments constituting the outermost layer sheath of a core strand, and ds, the diameter of outermost layer sheath filaments constituting the outermost layer sheath of sheath strands, is 1.05 to 1.25.

Steel cord for reinforcement of rubber articles and pneumatic tire using the same

A hole center detecting apparatus for positioning the hole of a spool and a cord accurately by determining the coordinates of two points of intersection between the inner circumference of the spool hole and a virtual straight line to compute the coordinates of the center of the hole and by moving the cord according to the computed coordinates of the hole center. A straightness measuring apparatus for measuring the curvature of a cord automatically by detecting the coordinates of three longitudinal points of the cord. A measurement apparatus for measuring a residual torsion automatically by measuring the rotation angle of the end portion of the cord before and after clamped, electrically.

Hole center detecting apparatus, straightness measuring apparatus, and residual torsion measuring apparatus

A steel cord for the reinforcement of rubber articles has a three-layer twisting structure comprising a core of 2 steel filaments, a middle sheath layer of 6 steel filaments and an outer sheath layer of 11 steel filaments, in which a ratio of filament diameter ds in the middle and outer sheath layers to filament diameter dc in the core (ds/dc) is within a range of 1.15-1.5 and a twisting pitch of the core is not less than 20 mm, and is used as a reinforcing member in a heavy duty pneumatic radial tire, conveyor belt and the like.

Steel cords for the reinforcement of rubber articles and method of

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Tochigi-ken, Japan

Eiji Kudo