Abstract: A tire having a tread composed of two non-conductive layers, each layer containing a circumferential insert of conductive mix, the inserts having a wider interface at the interface of the two layers. An apparatus for extruding a layer, provided with a conductive insert, including a main extruder for extruding a non-vulcanized, non-conductive layer, and a micro-extruder having an extrusion head, provided at its end with a nozzle, for extruding a conductive insert in the layer.

Abstract: A tire having a tread consisting of two circumferential layers of non-conductive material, each layer containing a circumferential insert made of a conductive mix and having on the contact surface between the two layers a circumferential footprint, the first of these layers having on the said surface a circumferential footprint with a circular path of width e, the second layer having on the said surface a circumferential footprint of width e′ lying across and having crests on either side of the circular path of the first layer, such that circumferentially between the two paths there are numerous points of contact which ensure electrical connection between the two conductive elements. The second layer with its insert is extruded from a main extruder for the extrusion of the portion of a tread in the unvulcanized condition, and a micro-extruder whose extrusion nozzle is fitted with a cutting edge and whose extrusion orifice is directed against a conveyor associated with the main extruder.

Abstract: A device for storage of an uncured rubber product is provided. The device comprised of:a bobbin composed of two flanges, each equipped with a border support portion fitted on the axially interior side of said flange, the border support portion having the general appearance of a spiral forming several turns, said border support portion being shifted forward, on each turn, axially toward the outside;an interleaf in the form of an elongated strip, resting on the said border support portions, the interleaf having a variable width, adapted to the axial distance between the said border support portions.

Abstract: The extrusion apparatus proposed effects an extrusion of the roller-spout type onto a cylindrical roller 7 associated with a profiled fixed wall 5 and a second extrusion of the roller die type onto a profiled roller 8 and an associated fixed wall 6, and then superimposes the extrusions in the passage between the rollers 7 and 8.