DE8901404U1 - Optical cable - Google Patents

Description

t ·

Description

The invention relates to an optical cable with a plurality of optical waveguides housed in a tubular sheath, in which several interconnected optical waveguides lie next to one another in a strip in one plane and several such strips are arranged one above the other in a stack (EP-OS 0 165 632).

When using optical fibers - referred to below as "LWL" for short - for transmission purposes in communications technology, they are processed in optical cables, for example. It must be ensured that the LWL is not damaged during production, transport or when laying the cable. Since they are brittle and have only a small elasticity, great care must be taken during production. The LWL must also be protected in the cable so that its functionality is guaranteed in the long term.

In the known cable according to EP-OS 0 165 632, the optical fibers in each band are connected to each other by a hardening varnish. The stack of optical fibers is housed in a protective sheath made of metal or sufficiently stable plastic. The sheath has a considerable oversize compared to the stack of optical fibers, which

i I« ti I Il I I Il

··· Il I ItII III 4 * «III I I lllll III·!

•&igr;&igr;·&igr;&igr; ill &igr;

II I

·

■ · t ■

I 1 > • I >

> I

accordingly lies loosely and movably in it. In order to ensure that the stack is sufficiently flexible, it is twisted lengthwise. The twisting process places considerable stress on the fiber optic cables during production, so that the risk of damage cannot be ruled out. This also applies during transport and when laying this well-known cable. Since the individual strips in the stack lie loosely on top of one another, they can easily detach from the stack and move uncontrollably in the relatively large sheath. This also disrupts the order of the fiber optic cables in the stack.

The invention is based on the object of specifying a cable with a stack of optical fibers grouped together in bands, whereby the risk of damage to the optical fibers is almost eliminated and in which the order of the optical fibers in the stack is permanently ensured.

This object is achieved in a cable of the type described above according to the invention in that the strips in the stack are connected at axial intervals along the entire length of the cable by firmly adhering connecting elements whose axial width is small in relation to the axial distances.

The connecting elements fix the bands with fiber optic cables at intervals in the stack so that they cannot shift significantly in the stack. However, the stack as a whole remains sufficiently flexible if the connection points are sufficiently far apart from each other. This is particularly important if the stack is arranged in a wave-like manner in the casing, for example, in order to give the fiber optic cables an upper length compared to the casing, which means that tensile loads exerted on the casing cannot affect the fiber optic cables. The low flexibility required for the wave-like course of the stack is due to the binders .

t f t ·

ti * 4 · ·

&iacgr;&igr;· 5

•· · * ti ie

i i'··' t r :

against each other, is not hindered by the imperfect connecting elements.

Advantageous embodiments of the invention will become apparent from the accompanying drawings .

Embodiments of the subject matter of the invention are shown in the drawings.

Kb show:

Fig. 1 shows a schematic representation of a cable according to the Invention partly in section. Fig. 2 shows a cross section through a cable used Stack of tapes with fiber optic cables. Fig. 3 to 5 Stack of tapes with fiber optic cables with

different designs of the connecting elements.

Fig. 1 shows a schematic representation of an optical cable 1 in which a large number of optical fibers 2 are arranged in a stack 3. The stack 3 consists of bands 4 lying one above the other, in which several optical fibers are combined in any shape lying next to one another in a plane. A cross-section through the stack 3 is shown in an enlarged representation in Fig. 2, in which, for the sake of simplicity, only one optical fiber 2 is shown for each band 4.

The stack 3 of strips 4 is movably arranged in a tubular casing 5. It preferably runs in a wave-like manner, as can be seen in Fig. 1. The stack 3 as a whole and thus also the strips 4 and the optical fibers 2 have an upper length compared to the casing 5 due to such a course, so that tensile forces acting on the latter cannot have a disruptive effect on the optical fibers 2. Such tensile forces can only lead to a flattening of the undulation with which the stack 3 is arranged in the casing 5.

• ttt · * · itii · &psgr; ·»»·

To hold the bands 4 together in the stack 3, connecting elements 6 are attached to the stack 3 at axial intervals, the axial width of which is small in relation to their axial distances. The distance between the connecting elements 6 can, for example, be selected so that it corresponds to a period length P of the stack 3 if the stack 3 is laid in a wave-like manner in accordance with Fig. 1, with contact with the casing 5. With this arrangement of the connecting elements 6, only a very small displacement of the individual bands 4 relative to one another is required.

The connecting elements 6 can be attached to only one side of the stack 3 in such a way that all the bands 4 are covered. However, it is possible to attach the connecting elements to two opposite sides of the stack. If the connecting elements 6 are only present on one side of the stack 3, they can be attached alternately on different sides at the locations following one another in the axial direction.

The connecting elements 6 can run at right angles to the longitudinal direction of the stack 3, as shown in Fig. 3. However, it is also possible to arrange the connecting elements 6 at an angle to the longitudinal axis of the stack 3, as shown in Fig. 4. In a further embodiment, which can be seen in Fig. 5, the connecting elements 6 can also be designed as bands that completely enclose the stack 3. It is sufficient if such a band is only fixed to one side of the stack 3, for example to the top band 4 made of LHL 2.

The connecting elements 6 can consist of a simple adhesive layer, which is applied, for example, to a finished stack 3 or as a strip

I l

J,,* J J · ♦ · > I

can be ejected. All materials are particularly suitable, such as hardening adhesives or hot-melt adhesives. Modified plastics, which become adhesive when heated, can also be used for the connecting elements 6.

·· ti ft I· ·· ·

·· f ti 9 t f » t ···

• t ·■>■ > « 111*1 · ····

·· ·· >■ «ei t ■· e

Claims (10)

Protection claims Optical cable with a plurality of optical waveguides housed in a tubular sheath, in which a plurality of interconnected optical waveguides lie next to one another in a plane in a band and a plurality of such bands are arranged one above the other in a stack, characterized in that the bands (4) in the stack (3) are connected at axial intervals over the entire length of the cable (1) by firmly adhering connecting elements (6) whose axial width is small y in relation to the axial distances. 2. Cable according to claim 1, characterized in that the axial distances are constant over the entire length of the cable (1). 3. Cable according to claim 1 or 2, characterized in that the connecting elements (6) are attached only on one side of the stack (3). 4. Cable according to one of claims 1 to 3, characterized in that the connecting elements (6) are attached at the axially successive locations on different sides of the stack (3). are. 5. Cable according to claim 1 or 2, characterized in that the connecting elements (6) are attached to two opposite sides of the stack (3). 6. Cable according to one of claims 1 to 5, characterized in that the connecting elements (6) are arranged at right angles to the longitudinal direction of the stack (3). 7. Cable according to one of claims 1 to 5, characterized in that the connecting elements (6) are arranged obliquely to the longitudinal direction of the stack (3). 8. Cable according to one of claims 1 to 7, characterized in that the connecting elements (6) are designed as an adhesive layer. 9. Cable according to one of claims 1 to 7, characterized in that the connecting elements (6) are designed as strips sprayed onto the stack. 10. Cable according to claim 1 or 2, characterized in that the connecting elements (6) are designed as bands which wrap around the stack (3) and are fixed at least on one side thereof. ·* ·« 11 tt &igr;*« ·· * I I I »I I 1*1 • * I
f* »II •.,.J { ....
IIM!