GB1578680A

GB1578680A - Ribbon-type cables

Info

Publication number: GB1578680A
Application number: GB10626/78A
Authority: GB
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 1977-05-31
Filing date: 1978-03-17
Publication date: 1980-11-05
Also published as: JPS53149042A; BE867679A; IT7823862A0; LU79724A1; FR2393327A1; ATA388278A; DK239878A; IT1095836B; DE2724536A1; AT354774B; NL7805818A

Description

(54) IMPROVEMENTS IN OR RELATION TO RIBBON-TYPE CABLES (71) We, SEMENS AKTIENGES ELLSCHAFT, a German Company of Berlin and Munich, German Federal Republic, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to a ribbontype cable comprising a plurality of optical fibre transmission elements arranged parallel to one another and caused to adhere to one another.

Ribbon-type cables are particularly suitable for many applications. Known forms of such cables are produced by calendering and lamination, by extrusion, or by similar processes involving pressure. Although these processes oan be used with advantage in cables provided with metal conductors, when light waveguides in the form of optical cables are used, difficulties occur since these production processes produce mechanical tensions in the light waveguides which may lead, for example, to an increase in the transmission attenuation.

The danger ob fibre breakage is also relatively high. In addition, fibres produced by extrusion generally have orientation strains which can lead to the formation of undesired effects by forces acting on the glass fibres.

Ribbon-type optical cables are already known in which glass fibres arranged parallel and next to one another are embedded between two foils which are then glued or welded to one another. The foils serve as carriers for the optical transmission elements which are further processed to form a cable from these ribbon lines; for example, they may be applied to a cable core, either to the core axis parallel or helically wound about the core, or, after being shaped to form a tube they may be inserted as a stranding element in a cable core or a stranding layer (see German Patent Specifications Nos. 2314 313; 2424041; and 2 355 854).

It is also known to produce optical fibre strips using self supporting individual fibres, in which case the individual fibres are glued to one another by means of an adhesive, the adhesive serving as a support for the optical fibre strip. Optical fibre strips of this kind do in fact have only a small thickness and good flexability, but they are liable to breakage. In order to eliminate this disadvantage, it has been proposed to arrange individual fibres assembled to form an optical fibre strip using an adhesive, on at least one strip-shaped carrier (see German Patent Specification No.

1 572 857). The strip-like carrier can consist of a metal, synthetic resin, or paper foil, or the like. Because they are connected to the carrier, the danger exists that when the cable strip is bent, the light waveguides will suffer a heavy loading, in particular, a tensile load.

Slackly or tightly encased light waveguides can also be assembled to form flat cables for specific applications. Since the cores are usually permanently encased, spraying or lamination processes can produce undesirable reactions on the light waveguide which may lead to increases in attenuation or even to the breakage of the light waveguide fibres. In particular, the heating necessary during extrusion, or damage to the common sleeve may affect underlying tight casing of the fibres and cause exposed casings to stretch, or to shrink.

It is an object of the present invention to provide a ribbon-type cable using optical fibres as transmission elements, in which there is substantially no thermal or mechanical loading of the light waveguide fibres during production.

According to the invention, there is provided a ribbon-type cable comprising a plu rality of optical fibre transmission elements arranged next to one another in substantially parallel relationship each said fibre element consisting of a core, a loose or tight inner protective casing around said core, and an outer casing made of flexible synthetic resin material, adjacent fibre elements being joined to one another at their respective outer casings.

The joining together of the outer casings of adjacent fibre elements can be effected by means of an adhesive or by dissolving the casing material along the line of contact. The cable of the invention can be produced by prou viding fibres consisting of slackly or tightly encased cores with additional outer casings of, for example, flexible polyvinyl chloride, which casings can be caused to adhere to one another in known manner. The outer casings can be provided in the same operating process as is used for the inner casings, or in a different process. When so produced, the light waveguide elements are virtually entirely free from thermal effects, and breaking forces occurring during the production can be maintained within tolerable limits.

The invention will now be further described with reference to the drawing, in which: figure 1 is a schematic sideffectional view of a ribbon-type cable according to the invention; and Figure 2 is a schematic side view of one form of apparatus for producing a ribbontype cable according to the invention.

The cable illustrated in Figure 1 comprises a plurality of light waveguide elements arranged parallel and next to one another.

Each of the light waveguide elements is in the form of an optical fibre having a core 1 and an inner protective casing 2 which is shown as being tightly seated on the core and which consists of a synthetic resin material or of glass, the fibre being provided with an outer casing 3 made of a flexible synthetic resin material. In the oontact regions 4 between the adjacent elements, the elements are caused to adhere to one another, for example, by the application of a suitable adhesive, or of a solvent which will partially dissolve the outer casings and clause them to adhere to one another.

In the system illustrated in Figure 2, a plurality of encased light waveguide elements 5 are unwound from a feed drum 6 and are conveyed over a series of rollers through an adhesive or solvent bath 7, whence they pass to a calendering section 8. In this section, calender rolls 9 are arranged, preferably provided with appropriate grooves for the recep tion of the individual elements which arrange the pretreated light waveguide elements 5 parallel to one another and bring them into mutual contact at the regions where they are to adhere to one another. The light waveguide elements, thus assembled to form a strip, then plass to a drying section 10 in which they are subjected for example to drying by radiation or dry air. Finally, the finished flat cable passes via a draw-ofl drum 11 to a winding arrangement 12.

WHAT WE CLAIM IS: 1. A ribbon-type cable comprising a plurality of optical fibre transmission elements arranged next to one another in substantially parallel relationship each said fibre element consisting of a core, a loose or tight inner protective casing around said core, and an outer casing made of flexible synthetic resin material, adjacent fibre elements being joined to one another at their respective outer casings.

2. A cable as claimed in Claim 1, wherein said inner casings are of a synthetic resin material, or of glass.

3. A cable as claimed in Claim 1 or Claim 2, wherein the outer casings of adjacent fibre elements are joined to one another by means of an adhesive.

4. A cable as claimed in Claim 1 or Claim 2, wherein the outer casings of adjacent fibre elements are joined to one another by mutually dissolving the casing material at the line of contact.

5. A ribbon-type cable substantially as hereinbefore described with reference to the drawing, and as shown in Figure 1 thereof.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. means of an adhesive or by dissolving the casing material along the line of contact. The cable of the invention can be produced by prou viding fibres consisting of slackly or tightly encased cores with additional outer casings of, for example, flexible polyvinyl chloride, which casings can be caused to adhere to one another in known manner. The outer casings can be provided in the same operating process as is used for the inner casings, or in a different process. When so produced, the light waveguide elements are virtually entirely free from thermal effects, and breaking forces occurring during the production can be maintained within tolerable limits. The invention will now be further described with reference to the drawing, in which: figure 1 is a schematic sideffectional view of a ribbon-type cable according to the invention; and Figure 2 is a schematic side view of one form of apparatus for producing a ribbontype cable according to the invention. The cable illustrated in Figure 1 comprises a plurality of light waveguide elements arranged parallel and next to one another. Each of the light waveguide elements is in the form of an optical fibre having a core 1 and an inner protective casing 2 which is shown as being tightly seated on the core and which consists of a synthetic resin material or of glass, the fibre being provided with an outer casing 3 made of a flexible synthetic resin material. In the oontact regions 4 between the adjacent elements, the elements are caused to adhere to one another, for example, by the application of a suitable adhesive, or of a solvent which will partially dissolve the outer casings and clause them to adhere to one another. In the system illustrated in Figure 2, a plurality of encased light waveguide elements 5 are unwound from a feed drum 6 and are conveyed over a series of rollers through an adhesive or solvent bath 7, whence they pass to a calendering section 8. In this section, calender rolls 9 are arranged, preferably provided with appropriate grooves for the recep tion of the individual elements which arrange the pretreated light waveguide elements 5 parallel to one another and bring them into mutual contact at the regions where they are to adhere to one another. The light waveguide elements, thus assembled to form a strip, then plass to a drying section 10 in which they are subjected for example to drying by radiation or dry air. Finally, the finished flat cable passes via a draw-ofl drum 11 to a winding arrangement 12. WHAT WE CLAIM IS:

1. A ribbon-type cable comprising a plurality of optical fibre transmission elements arranged next to one another in substantially parallel relationship each said fibre element consisting of a core, a loose or tight inner protective casing around said core, and an outer casing made of flexible synthetic resin material, adjacent fibre elements being joined to one another at their respective outer casings.