The subject of the présent invent on is the proαuc tion of a cable conduit system for the Laying of cables, generally buried cables, of great factory length, for example waveguide cables. As is knoun, the Connecting of t o factory lengths possessing waveguides involves a considérable out lay in ternis of technology and expenditure. For this rea son efforts are made to keep thèse connection or splicing points to a minimum by manufacturing long length of cable, which can amount to 1,000 m or more.

The problem underlying the invention described hèr consiste, then, in drawing such Long Lengths of cable int a cable conduit system in one pull, and doing so irres¬ pective of the topographi ca L conditions of the terrain in which the cable conduit system is Laid and without aking use of specialised or heavy equipment.

Expérience now shows that coating the drawing éléme and the interior surface of the conduit with a lubricant is not sufficient to overcome the frictional forces arisin in accordance with the law e^* , in the bends in the con¬ duit, which a r e sometimes three-dimensiona L.

The conventional technique for laying cables in trenches makes use of cable-laying roliers to reduce thèse frictional résistances, particularly where the path of the cable undergoes a change of direction or a curvatur The object of the présent invention is to apply thi technique to the spécial case of drawing cables into the cable conduit described, with the aim of providing a self- contained, complète and leak-tight p peline system.

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In accordance with this ob ect, the invention re¬ lates to a method whose distinctive feature consists in the fact that the devices according to the invention are in¬ stalled at points where the run of the cable conduit undei— goes critical changes of direction or curvatures. Thèse devices, which are leak-tight themselves, are also connec¬ tée) to the cable conduit in a manner which is tight against dust _Λ water and moisture. Support roliers and guide rol¬ iers are arranged in various planes within the interior space of thèse devices.

The effect achieved by the invention is that a cable conduit manufactured in great lengths (for example 1,000 m) which is delivered ready-to-use to the construction site and is laid there, can immediately be used for the drawing- in of cables. This conduit contains the drawing élément necessary for drawing in the cable, and is treated in a manner such that the slip résistance of the conduit is low and the conduit and drawing élément are protected against corrosion. One of the possible, non-li ited types of embodiment consists, for example, of a high-density polyethylene pipe with galvanised steel wire laid therein and, if appropriate containing lubricant which simultaneous ly imparts to the ga vanised steel wire additional protection against corrosion. Clearly, the invention relates to the.se devices, which are referred to as roller bends in the text which follows. Thèse roller bends represent a completely novel commercial article.

For the sake of clarity, an exemplary embodiment is

described iι>. the text which follows, with référence to the attached fi gures .

Figure 1: view of an open roller bend; Figure 2: view according to the section II-II in Fi gure 1 ;

Figure 3: view according to the section III-III in Fi gure 1 ;

Figure 4: side view of a partly open roller bend. The axial sections of the cable conduits are desig- nated (16) in the figures.

According to the invention, one or more such roller bends, according to the example in the drawing, are in¬ stalled in the cable conduit at points of critical changes of direction or curvatures. The roller bend con- . sists of two half-shells (10) and (12), as a resuit of which it is not necessary to eut the drawing élément loca- ted in the cable conduit when installing the roller bend. The two half-shells are held together by screws (14). The entrance to and the exit from the roller bend are so designed as to be able to accept the ends (16) of the con¬ duit which has been eut at the critical point, and form a leak-tight seal with thèse by means of the gaskets (18 ⁾ .

Guide roliers and support roliers (22) are arranged on spindles (24) within the interior space (20) of the roller bend. The spindles (24) are ounted in the recesses (26) and (28) which are présent in the correspondi ng half- shells (10) and (12). The roliers (22) are in each case located on the inside of the roller bend.

Advantageous ly, a roller ⁽ 30 ⁾ running on a spindle

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(32) is attached within each half-shell and is aligned per- pendicularly to the spindles (24 ⁾ of the roliers (22).

In this manner effective guidance and easy sliding of the cable (34) are achieved when the latter is drawn in through the roller bend according to the invention.

During the drawing-in of the cable, the cable (34) will thus unroll on the roliers (22) and be additionally gurded by the roliers (30), depending on the bend in each case. The gask-et (36) Lying in the grooves (38) of each half-shell ensures the sealing-off of the interior space (20) of the roller bend.

If appropriate, projections (40) and fixed centring éléments (42) may also be provided in the interior space (20) to provide improved and error-free guiding of the cable to be drawn through the roller bend.

The construction material of the roller bend may be metallic. More advantageous l , it is made fro corro- sion-free, synthetic material. The degree of deflection of the roller bend can be designed for any change of direction by the cable conduit.

The device described in the preceding text and the corresponding method are capable of further development and are to be regarded only as a non-limiting example.

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