FI74823C - Light guide device - Google Patents

Description

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SUOMI FINLAND

(Fl) (21) Patent application - Patentansökning 780325 (22) Application date - Ansökningsdag 01.02.78

National Board of Patents and Registration (23) Start date - Giltighetsdag 01.02.78

Patent- och registerstyrelsen (41) Has become public - Bhvit offentiig 26.08.78 (44) Date of publication and of publication - 30.11.87

Ansokan utlagd och utl.skriften publicerad (86) Kv. Application - Int ansökan (32) (33) (31) Privilege claimed - Begärd priority 25-02.77

The Federal Republic of Germany (DE) P 2708878. ^ (71) AEG-Telefunken Kabelwerke Aktiengesel1schaft, Rheydt, Mönchengladbach, The Federal Republic of Germany-Förbundsrepubliken Tyskland (DE), Hebrew ,

German Federal Republic of Germany (7) Oy Kolster Ab (5M Optical fiber device - Ljus 1edaranordning

The invention relates to a light guide device consisting of a stable hose and an optical fiber or fiber group inside it, which runs inside the hose without touching the inner wall of the hose.

By optical fibers is meant in this context fibers of a material suitable for transmitting light in the infrared, visible ultraviolet region or in a part of this region of the electromagnetic spectrum. The optical fibers may be surrounded by a protective coating to protect their surface. Primarily, such optical fibers are used for telecommunications.

Optical fibers are mechanically very sensitive. For further processing, insertion and installation, they are therefore arranged individually or as a group of a few inside the protective covers. Such optical fiber devices are referred to herein as optical fiber devices. They can act as transmission lines immediately or only after fitting the corresponding outer sheaths. But they can also be 2,74823 braids with each other as optical braiding elements and thus can form the core of the optical cable. During braiding, the braiding members are subjected to strong bending and tensile stresses. There are also bending and tensile stresses during the subsequent installation and installation of the cable, which affect the light guide devices. In this case, the optical fibers contained in the light guide devices may be damaged or their transmission quality may deteriorate.

In order to keep the bending and tensile stresses of the optical fibers present in the braiding of light guide devices away, it is known to fit these loosely into tubular casings which receive mechanical stresses. The optical fibers are located in the tubular casings in a freely movable manner. Such a photoconductor device is known from German application 2,556,861. The disadvantage of this known photoconductor device is that it must first be wound on a drum after its manufacture. However, when wrapped around the drum, the optical fibers do not remain at the center of the hose, but settle inside the hose against the wall closest to the center of the drum. If this light guide path for braiding is now stretched straight again, the fibers will be shorter than the hose and will therefore stretch, often leading to fiber breakage.

It is now an object of the present invention to provide a light guide device which retains the advantages of a loose coating of optical fibers, thus reliably protecting the optical fibers from tensile and compressive stresses, but in which wrapping after manufacture does not lead to length differences between the hose cover and the optical fibers. . After manufacture, the photoconductor device must be able to be wound on a drum and extended straight again without risk of breakage.

This object is solved by a light guide device according to the invention of the type described at the beginning, so that a thread of cushioning material wound helically around the optical fiber or group of fibers keeps it in a slightly eccentrically helically line wrapped around the axis of the hose.

The device may have one or more strands of cushioning material wound around the optical fiber or group of fibers. The filaments may be of fibrous material 3,74823. Wool yarns have proven to be very well suited for this purpose. The optical fibers of one fiber group can be fitted to the light guide device according to the invention in braided form.

In order to manufacture the light guide device according to the invention, it is possible to first wrap a support wire, which is e.g. wool, around the optical fiber or fiber group, and then to extrude a hose around this device. But the optical fiber wrapped around the wool wire can also be fitted into a longitudinally open hose, which is then again closed or self-closing. This method is described in the applicant's German patent application 2,651,725.9. However, it is known to use helical spacers in connection with electro-coaxial cables which hold the inner conductor or the conductor axis. However, in the light guide device according to the invention, the optical fibers are not located directly in the coaxial position, but are lightly wound eccentrically around the hose axes. The very rigid connection between the outer conductor and the inner conductor provided by the spacer clips in connection with the coaxial cables does not indicate the advantages of the structure proposed according to the invention in which the optical fiber, supported by a fibrous wool, rotates loosely around the hose axis.

The invention has the advantage that the optical fibers are not freely movable in the hose, but are held with a predetermined eccentricity around the hose axis by a line rotating helically. Thus, when the optical fibers are wrapped against the hose wall when wrapped around the drum, it is prevented from leading to length differences which, when the light guide device is extended, could lead to the rupture of the optical fibers. However, the advantages of loose fitting of optical fibers are retained because the support elements in the device do not impede the mobility of the fibers in the hose. The low support force of the support elements on the fibers allows relative movements in the longitudinal direction of the device. When the radial pressure on the hose is present, the fibers have enough space to give. The arrangement according to the invention allows the treatment of optical fibers without a coating.

4,74823

An embodiment of the invention is shown in the drawing. It shows a plan view and four sections with the light guide device in different positions.

The optical fiber or group of fibers is denoted by reference numeral 2. A wool yarn 3 is wound helically around the optical fiber, which supports the fiber at a distance from the inner wall of the hose 1 and gives it a slightly eccentric helical rotation about the hose axis 4. The four cross-sections A to D show the eccentric state of the optical fiber in four different positions. It should be noted that the optical fiber rotates longitudinally with a small radius about the hose axis.

Claims (4)

5,74823 A light guide device consisting of a stable hose (1) and an optical fiber or fiber group (2) inside it, which runs inside the hose (1) without touching the inner wall of the hose, characterized in that a cushioning material is wound helically around the optical fiber (2) or fiber group. a thread (3) of substance keeps it slightly eccentrically helically in a line wrapped around the hose axis (4). Photoconductor device according to Claim 1, characterized in that the filament (3) consists of a fibrous material. Photoconductor device according to Claim 1 or 2, characterized in that the strand (3) is a wool yarn. Light guide device according to one of Claims 1 to 3, characterized in that the optical fibers of the fiber group are not braided with one another.