Sumitomo Electric Industries, Limited

Shigeo Masuda

Morihiko Katsuda

Toshifumi Hosoya

Isao Ueoka

Takeshi Imai

Nobuyuki Asano

Naohiro Kako

Optical-transmission fibers serve to transmit signal over some distance. Said fibers have traditionally been constructed of a glass fiber; consisting of a central core and an outside clad, a surrounding soft layer around said fiber and a hard layer around the soft layer. Because of the material construction, said fibers had high dynamic losses. By altering the materials used around the glass fiber, the present invention has successfully dramatically reduced the dynamic loss and therefore greatly improved the possibilities for signal transmission. The organic material used to enhance transmission ability may vary but the effect is such that the dynamic loss remains low as compared to any previous art.

Plastic-coated optical transmission fiber and an estimating method

A process for producing an insulating twisted electric wire having a reduced overall diameter with an insulating coating of high quality. The insulating coating has a thickness in a range of 3 to 100% of the radius of a smallest circle circumscribing the assembled set of twisted conductors. The insulating coating is formed by two or more cycles of coating and curing an insulating paint. Preferably, a bottom layer of the insulating coating is formed by applying a heat-curable insulating paint with a felt applicator or with a roller coating device. The heat-curable insulating paint should have a viscosity of not more than about 300 cps at 30.degree. C.

Process for producing an insulated twisted electric wire

A process for producing an insulated rectangular wire adapted for edgewise winding. A round wire of copper, copper alloy, aluminum or aluminum alloy is drawn through a die in a tandem-extrusion apparatus. The drawn wire is then electrolytically cleaned, following which an insulating coating is applied to the cleaned surface. The insulating coating is baked, and finally the insulated wire is subjected to at least one cycle of rolling. Preferably, the drawing is done with a single die and capstan to thereby remove any surface defects in the conductor having a size of 3 .mu.m or greater. The capstan should be made of a material softer than the material of the conductor. Further, it is preferred that fresh lubricating oil containing no metal dust be applied to the surface of the conductor during the drawing process.

Process for producing insulated rectangular wire

An enameled wire having resistance to overload which comprises an electric conductor and a baked wire enamel coat is disclosed. The wire enamel coat is applied to the conductor through a die from wire enamel comprising a silicone resin having incorporated therein 50 to 200 phr of particles of an inorganic tabular crystalline material that have a maximum average particle size not greater than 80.mu., an average not greater than 40.mu. and an average aspect ratio between 30 and 100 and which react with the silicone resin at elevated temperatures to become a ceramic and which have been surface-treated with a coupling agent, a surface active agent or a coating agent. The tabular crystals in the wire enamel coat are orientated parallel to the surface of the conductor. The enamel coat has good adhesion to the conductor and will not easily crack or peel off the conductor even when subjected to high temperatures and adverse physical stress.

Growing community of inventors

Aichi, Japan

Shigeo Masuda