HRP980182A2 - Ploymeric pipe - Google Patents

Abstract

The protective tubing Ä1Ü that is used with such as optical conductors and cables has an internal profile Ä11Ü that is formed with grooves Ä12Ü. Cables Ä2,3Ü of different sizes are fed through the tubing and these make contact with the surface between the grooves. The cable is fed through the tubing with the aid of compressed air and the flow of the air through those grooves enclosed by the cable creates an air cushion effect. This reduces the friction force. The tubing is produced in a polymer.

Description

The invention relates to a tube made of polymer material for receiving retractable means such as cables, light wave guides, pipes and the like, wherein the inner circumference of the tube has a ribbed structure.

A tube of this type is known from DE 38 02 493 C1, the inner circumference of which is made capable of sliding on its surface. For this purpose, the tube is made of two concentric polymer layers. The inner, thinner polymer layer has a defined amount of additives to reduce friction. It has a ribbed structure, in which these additives are placed. Cables and similar means, which are drawn into that pipe, slide along the top of the profiling, where this sliding is positively enhanced with the additive parts introduced in the inner layer.

From DE 38 30 942 C2, a further tube of this type made of synthetic material for receiving retractable means is known, which is equipped with an inner tube layer, to which a sliding agent in the form of silicone oil is added during production. This inner layer has internal profiling, in which ribs are made, which have a triangular, trapezoidal or wavy cross-section.

Further tubes of this type have variations in terms of sliding ribs, as described in DE 35 29 541 A1, or show variations in the geometry of the ribs, eg DE 35 39 304.

The tubes of the known state of the art are supplemented with tubes with a smooth inner surface, which provide optimal friction coefficients with minimal cable wear when pulling in cables with rope tensioning winches.

Tubes with a ribbed inner surface according to the state of the art provide improved friction values when blowing light coaxial cables as well as glass fiber cables. As a special disadvantage of this procedure, the wear and tear of cable sheaths or pipe ribs increases with such insertions. If, for example, the ribs of the protective pipe are made of a hard polymer material, the wear on the rib jacket increases, and if the ribs on the pipe rim are made of soft polymer material, the wear of the pipe ribs increases when the cable is shot. In any case, this wear and tear is harmful, because peeled polymer particles remain in the tube interior and can be stacked in arbitrary places, whereby the lying furrows between the ribs are filled with these free polymer particles, which in this form can act as a brake when pulling in the cable.

Here the subject invention appears, which has made it its mission to combine the low sliding friction and low wear of the cable jacket of smooth inner surfaces with the advantages of cable tubes with ribbed inner surfaces in blowing glass fiber cables and lightweight coaxial cables. In the context of the invention, it is therefore proposed that the inner smooth tubular circumference is divided into dividing segments, which are separated from each other by means of slots placed between the dividing segments.

The dividing segments form partial areas of the smooth inner tube surface, which means that they do not create a pointed or rounded rib shape. The cable to be blown rests on the smooth inner pipe surface during the blowing process at the corresponding dividing area, where it is always a line-shaped contact here. This achieved a minimum of sliding friction and wear of the cable jacket, as was described for pipes with a completely smooth surface in the state of the art.

With the arrangement according to the invention, between these dividing areas of the smooth inner tube surface with grooves, it is always guaranteed that the blown compressed air penetrates under the cable and thus the formation of an air cushion under the cable is ensured. Thus, according to the invention, the advantages of internally corrugated cable protective tubes are combined with the advantages of cable protective tubes with a smooth inner surface.

Preferably, the ratio of measurements between the dividing segment and the groove is from 1.5:1 to 5:1. In this way, cables of various diameters can be blown into the protective tubes with the advantages according to the invention, with minimal wear at a long blowing length.

In one preferred embodiment, the inner tubular circumference, with grooves separated by dividing segments, is a layer of hard polymer material. With this multi-layer construction of the pipe wall section, the inner pipe in the area of the dividing segments and grooves is produced from one hard polyethylene of high density by co-extrusion process. This measure guarantees a further reduction of sliding friction and thus cable wear in contact with a blown cable and as a dividing segment of a smooth tubular inner surface of a dividing surface with a relatively wide contact area. The inner surface of the protective tube produced according to the invention provides an optimal combination between the positive features of protective tubes with a smooth inner surface and protective tubes with ribs and a profiled inner surface. At the same time, reduced sliding friction is achieved with a smooth tubular inner surface - achieved due to the dividing segments - a minimal wear of the cable sheath at the same time, thanks to the grooves, the creation of an air cushion under the cable is achieved, which increases the shooting length of such a cable extremely.

The drawing shows schematic examples of the pipes according to the invention; is shown:

Sl. 1 cross-section of the protective tube with cables inserted,

Sl. 2 measures of the dividing segment and the slot in different designs.

Figure 1 shows a protective tube 1 with a single-layer wall section. Divided dividing segments 11 are located on the inner circumference, which are each separated from each other by slots 12.

Cables 2, 3 of different sections are inserted into the lumen 13 of the protective tube 1. For example, cable 2 has a diameter of 12 mm, while cable 3 has a diameter of 20 mm. The cable 2 lies on the dividing segments 11' and covers the groove 12'. When compressed air is blown in, it also reaches the slot 12', whereby the cable 2 is lifted into the lumen 13 of the protective tube 1, and carried on the air cushion. This action is also supported by air, which flows longitudinally through the adjacent grooves 12" to the side of the cable 2. In this way, the wear of the cable jacket is minimized and the used compressed air is optimally used for transporting the cable 2 in the lumen 13 of the protective tube 1.

With cable 3, this action takes place analogously. The cable 3 lies along its entire circumference on the dividing segments 11', which is self-explanatory due to its larger cross-section. The compressed air of the slots 12'' and 12'' lifts the cable 3 - as described with the cable 2 - into the lumen 13 of the protective tube 11. This movement is additionally supported by the compressed air from the slot 12'', which flows along the cable jacket along the cable 3. and thus improves the floating of the cable 3.

Figure 2 shows the ratio of the dimensions of the dividing segment 11 and the groove 12 in different designs. In a, the ratio of measures 1.5:1 is shown. This ratio is usefully applied only where larger diameter cables must be inserted into protective pipes.

In b, a ratio of 2:1 is shown between the dividing segment 11 and the slot 12. And this ratio should be applied expediently only when a cable with a larger diameter is inserted. In both cases, as a rule, with cables of smaller diameters, the carrier air would not be captured under the cables, as it should be in the optimal case, but would flow laterally next to the cable jacket, which would insufficiently achieve the desired floating effect.

In c and d, the ratios of measures 3:1 and 5:1 are shown. With these ratios, smaller diameter cables must also be lifted in an optimal way into the lumen 13 of the protective tube 1, since here, based on the chosen ratio of measurements, the air current arrives from the slot 12 directly under the cable, and thus the lifting effect is optimal.

Separating segments 11 according to the invention with grooves 12, which separate them, are variable in their direction. They can be directed axially along the entire length of the protective tube 1, and they can also be arranged in the form of a coil, in an arc or a similar shape along the inner circumference of the protective tube 1.

Claims (3)

1. A tube made of polymer material for receiving retractable means such as cables, light wave guides, pipes and the like, wherein the inner circumference has a ribbed structure, characterized by the fact that the inner, smooth circumference of the tube is divided into dividing segments (11), which are between the dividing segments (11) located grooves (12) separated from each other. 2. The pipe according to claim 1, characterized in that the ratio of measurements between the dividing segments (11) and the groove (12) is from 1.5:1 to 5:1. 3. The pipe according to claims 1 and 2, characterized in that the inner circumference of the pipe by means of grooves (12) separated by dividing segments (11) is one layer of hard polymer material.