DE2541178A1 - OPTICAL CABLE - Google Patents

Description

STANDARD ELECTRICAL LORENZ 2541

SHARED COMPANY

Stuttgart 3

H.Harbort-3

Optical cable

The invention relates to an optical cable, the cable core of which contains a tensile element in the center, to the further tensile elements and light guides are arranged.

Optical cables are primarily used to transmit information using optical frequencies intended. As a transmission medium, they contain light guides made, for example, of glass or quartz fibers exist. In one embodiment of the light guide, it consists of a glass fiber with a circular cross-section, those with a cylindrical shell made of a glass with a lower refractive index than that of the core is surrounded. But there are also other embodiments known from light guides. However, all light guides have a disadvantageous property in common that they are against mechanical stresses of any kind are very sensitive. Any mechanical impact can be detrimental the fiber optic transmission properties, so that care is taken with optical cables must be that such mechanical action is reduced to a minimum in their manufacture and use is.

September 12, 1975, Bö / Ku

709812/0512

H.Harbort-3

An optical cable is known (DT-OS 2 429 670), The core of the cable contains a tensile element in the center, such as a steel wire, around which several strands are formed Structures are arranged, which are surrounded by extruded polyethylene sheaths bundles more optical Fibers and non-optical reinforcing fibers are made of steel. To prevent the optical fibers from being scratched, can be cut or otherwise damaged, are both in the known optical cables the cavities present in the bundles as well as in the cable core between the bundles with a paste-like Material, such as Vaseline, filled.

The known optical cable has the desired properties only to a very limited extent. A disadvantage occurs already during the manufacture of the bundle, because the stranding of the unprotected, mechanically weak optical Fibers is very difficult. You can easily be exposed to impermissible mechanical influences.

Since neither the optical fibers nor the non-optical gain gases are encased, there is there is direct contact between them via the paste-like material. Because with cable movements a relative movement occurs between optical fibers and non-reinforcing optical fibers is rubbing and scratching between them unavoidable because the paste-like material can be squeezed away. For the same reason, a mutual punctiform compressive stress of adjacent optical fibers, which are responsible for the transmission

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H.Harbort-3

properties is also disadvantageous, cannot be avoided. Thus, the preservation of the optical transmission properties absolutely necessary separation of the optical fibers from the non-optical reinforcing fibers cannot be guaranteed with certainty.

Added to this is the fact that the sliding property of the pasty The material is strongly dependent on temperature, so that its optimal effect only in a limited temperature range is available. At high temperatures the viscosity of the paste is so low that it is easily squeezed away. At low temperatures, its viscosity is so high that there is no longer any lubricating effect, which in disadvantageously no more mutual movement between the fibers allowed.

The application is therefore based on the task of creating an optical cable in which there is direct contact between the light guides or between the light guides and the tensile elements are definitely excluded is. In addition, both should not be able to exert pressure on one another, but the light guides should nevertheless Have sufficient freedom of movement when bending the cable.

This object is achieved according to the invention in that the tensile strength element has a soft, resilient core in the core Sheath is provided, around this in one or more layers, alternately tensile strength per layer Elements with a soft, flexible cover and light guide with a significantly harder coating than the cover of the tensile elements are stranded, and each layer is wrapped in a soft film

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The light guides provided with a hard coating can Can be handled better in further processing because of their resistance to mechanical influences is improved. The soft padding of the tensile elements and the hard coating on the light guides prevent it certainly a disadvantageous direct contact between the two. Damage to the light guide is therefore certain prevented.

The tensile elements are also unable to exert any pressure on the light guide because the latter is flexible Envelope is absorbed. An impairment of the optical fiber transmission properties is therefore excluded under normal operating conditions.

The light guides also have the necessary mobility in the new cable because the sheathed ones are tensile Elements also have a larger diameter, which creates additional room for movement for the light guides is available.

Further advantageous details of the invention are in

the claims 2 to 5 included. The attached figure

shows an embodiment of the new optical cable in cross section.

The tensile element 5 can be seen in the center, which is provided with a soft cover 6. Around this are alternately those with a soft cover 4 provided tensile elements 3 and those with a hard

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Coating 2 provided light guide 1 stranded. A soft, for example foamed plastic band is around this core 7 wound, over which, as is common practice with cables, the - not shown - cable sheath made of PVC or PE can be arranged. For example, threads made of steel, polyamide or glass can be used as tensile elements 3, 5 will. A polyamide, polycarbonate, polyethylene terephthalate, for example, is suitable for the coating 2 or polypropylene and the cover 4 or 6 can e.g. be made of foamed PE, foamed PVC or foamed PUR exist.

The mutual sliding of the strands can also be improved in that they are known per se Way are powdered with talc.

5 claims

1 sheet of drawing

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Claims (1)

H.Harbort-3 Expectations Optical cable, the cable core of which contains a tensile element in the center, around which further tensile elements and light guides are arranged, characterized in that the tensile element is provided in the core with a soft, flexible sheath, around it in one or more layers, per Layer alternately tensile elements with a soft, flexible cover and light guide with a much harder coating than the cover of the tensile elements are stranded, and each layer is surrounded by a wrapping of a soft film. Optical cable according to Claim 1, characterized in that the tensile elements with sheath are larger Have a diameter than the light guides with a coating. Optical cable according to Claims 1 and 2, characterized in that that the coating of the light guide made of a polyamide, polycarbonate, polyethylene terephthalate or polypropylene consists. Optical cable according to Claims 1 to 3, characterized in that that the casing of the tensile elements is made of a foamed plastic such as PE, PVC or PUR. September 15, 1975, Bö / Ku 709812/0512 H.Harbort-3 5. Optical cable according to claims 1 to 4, characterized in that that the wrapping film consists of a foamed plastic. 709812/0512