Compagnie Generale Des Etablissements Michelin

Jean-Louis Charvet

Jean-Pierre Cesar

Jose Asquier

Christian Garcia

Maurice Bouju

A reinforcement assembly to be impregnated with a plastic or rubber material for reinforcing an article, such as a pneumatic tire, the assembly having three layers of cords: a core layer, an intermediate layer and an outer layer. The intermediate layer and the outer layer have the same direction of winding and the same pitch. When the core layer is wound in the same direction as the intermediate layer, the pitches of these layers differ in such a manner that the ratio between the difference in the values of these two pitches and the larger value of these two pitches is at least equal to 0.30. In the intermediate layer the axis of each cord is arranged along a helix such that the ratio between the radius of curvature of said helix and the diameter of said cord is less than 75.

Assembly of reinforcement cords for plastic and/or rubber materials

A reinforcement assembly comprises from one to three layers of threads, one of which is a central layer having one or more shaped threads, i.e., threads having a center of gravity and a contour in an intersecting plane perpendicular to the longitudinal direction of the thread, the distance from any point on the contour to the center of gravity depending on the position of the point on the contour. The twist pitch of each shaped thread is different from the winding pitch of the shaped thread in the layer in which it is located and if the element comprises three layers, the winding pitch of the outer layer is different from the winding pitch of the subjacent layer. Reinforced articles include such assemblies impregnated with a material, in particular pneumatic tires.

Reinforcement assembly having a layer comprising a shaped thread:

A reinforcement cable is formed of an assembly of strands. Each strand is formed of two wires wound around each other in the same direction, with a constant pitch whose length is less than 300 mm. The two wires have linear contact with each other in the form of a helix. These helices have the same direction and the same constant pitch length. The assembly is formed of two strands of the same length of pitch and wound in opposite directions and/or it is formed of two to four strands such that the assembly has the same length of pitch and wound in the same direction as one strand and, with respect to another strand, a different length of pitch and/or wound in an opposite direction.

Reinforcement cable formed solely or at least in part of an assembly of

During the winding of the layers of the wires of a tire bead ring, a piece of ribbon is interposed at least twice per revolution between two consecutive layers of wires, the ribbon being formed of a thin flexible support bearing on each of its faces a layer of a material which adheres both to the support and to the wires.

Process for holding together the wires of a package bead ring for tires

In order to obtain a bead ring for tires which is both lighter and stronger than the known bead rings, the bead ring is formed of an annular core, for example of steel, surrounded by at least one layer formed of at least one strand of continuous nonmetallic filaments which are practically parallel to each other and free of impregnation, which strand is wound around the core in the same direction to a layer thickness at least equal to twice the average diameter of a filament and with a winding pitch p less than 2.sqroot.ac (in which a is the radius of a circle equivalent to the perimeter of the cross section of the core and c is the average circumference of the core) and a twist in the same direction as the winding and equal to one turn per pitch.

Bead rings for tires

A method of manufacturing a tire bead ring of the package type by winding metal wires on a form of revolution, the radially inner face of the tire bead ring having a frusto-conical shape of half angle .alpha. at the apex and of radius R with respect to the axis of rotation of the tire bead ring, in which a permanent circular deformation is effected on the wires prior to their winding on the form of revolution, is improved due to the fact that the permanent circular deformation is a radial deformation of a radius substantially equal to the radius R of the tire bead ring and is effected on the wires whose one principal axis of inertia of their cross section is inclined by one angle .alpha. with respect to the axis of winding of the wires on the form of revolution.

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Clermont-Ferrand, France

Jean-Louis Charvet