Industrie Pirelli Societa Per Azioni

Industrie Pirelli S.p.a.

Societa Cavi Pirelli S.p.a.

Sergio Longoni

Antonio Portinari

Elio Occhini

Telecommunication elements each comprising one or more optical fibers surrounded by one or more layers of a plastic are wrapped with a non-metallic protective layer. The protective layer is enclosed by a metal tube which has at least portions which press into the protective layer so as to provide dimensional stability to the elements and protective layer within the tube. The metal tube may have a cylindrical inner wall or be a corrugated tube, and such tube protects the optical fibers with respect to electrical discharges.

Optical fiber cable including layers which compensate for thermal

A method of manufacturing elements for an optical cable, such elements including a tube of an elastic material, e.g. a synthetic resin or an elastomer, which loosely encloses one or more optical fibers. Preferably, the fiber or fibers are longer than the enclosing tube and the tube is filled with a material which prevents the migration of water, etc. The tube in mechanically stabilized form and the optical fiber or fibers are advanced toward a traction zone where the tube is pulled. Prior to the traction zone, the tube is slit or cut longitudinally through one thickness of the wall, the cut edges are spread apart and the optical fiber or fibers are inserted into the tube through the gap between the cut edges. Optionally, filling material is also inserted into the tube through such gap or a downstream gap subsequently formed. The tube-optical fiber assembly follows a straight line downstream of traction zone to a collecting point. The tube may be tensioned downstream of the traction zone either by a pulling wheel or the collecting means. Also, apparatus for performing the method including slitting or cutting means, rectilineal traction means, collecting means and optionally, separate pulling means following the traction means.

Optical cable elements

Method and apparatus for manufacturing optical cable elements

One or more optical fibers are loosely enclosed in a tubular plastic sheath so as to be slidable with respect to the sheath. The fibers may be longer than the length of the corresponding surrounding sheath. The sheathed fibers are wound around a core and covered with a further sheath to form a cable. In the process, the optical fiber is treated with an anti-adhesive material before the sheath is extruded thereover and during the subsequent processing the sheath, which has a length greater than the length of the enclosed fiber, either because of its temperature or because of mechanical stretching, is allowed to contract while in non-slidable relation with the fiber, thereby providing a fiber length greater than that of the sheath.

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Milan, Italy

Sergio Longoni