SK18182001A3 - Dimensionally stable corrugated tube and method for producing same - Google Patents

Abstract

The invention relates to a method for producing a plastic dimensionally stable corrugated tube (1) which is provided, in particular, for protectively enclosing electrical lines and which comprises a slotted opening (4) that extends along a contour line. After the corrugated tube (1) has been extruded and provided with corrugated peaks (2) and corrugated troughs (3) inside a corrugator, it is cut open along one of any of its contour lines, whereby the cut is not made as a radial cut, but is made with an angle that deviates therefrom or is made with a sequence of successive angles of this type. The corrugated tube (1) is then compressed, whereby the edges (5) of the slotted opening slip over one another. Finally, after the corrugated tube has completely cooled, the edge (5) of slotted opening lying on the inside is guided outward and is laid over the other edge (6) that was previously laid on the outside.

Description

A process for producing a shape-stable corrugated pipe and a corrugated pipe

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Technical field

Method for producing a shape-stable corrugated pipe consisting of plastic and designed in particular for the protective coating of electrical conductors, with a slot opening extending along the sheath line. The invention further relates to a corrugated pipe produced by this method.

BACKGROUND OF THE INVENTION

Such corrugated tubes, especially made of plastic, are known and used especially in the manufacture of automobiles as protective sheaths for electrical conductors. A longitudinal slit formed in such corrugated tubes or a slot opening thereof serves to protect the cable, usually in the form of a bundle of cables, or in the form of a bundle of branching cables, inserted into a corrugated tube.

A variety of designs are known in the art to form the slits of the slotted openings of such corrugated tubes so that after the cable has been manually inserted, the edges can be brought into contact with each other and the closure can also be opened again with or without tools.

Depending on the formation of the edges of the slots or the corresponding closing shapes of the longitudinal slots, it is less or more time to close such pipes, notwithstanding that the formation of the edges of the longitudinal slots can be made less or more costly.

Thus, for example, it is known to form both edges of a slot forming an opening of a corrugated tube which together form a removable closure. In this case, such edge shaping can be varied, for example in the manner of a known zipper or also of a so-called Velcro. A disadvantage here is that after insertion of the cable bundle into the corrugated pipe, it is necessary to ensure that the edges of the corrugated pipe slots persist against each other, or that they are mutually positioned in such a position that the forming forms a cohesive joint. Thus, according to DE 196 41 421 A1, a removable closure can be provided as an overlap of the two molded edges, wherein the moldings are in each case provided with radially protruding protrusions, which snap into each other. In such embodiments, re-opening of the longitudinal slits is difficult.

In contrast to formations which are always spaced in the longitudinal direction of the slots, the edges of the slits of the corrugated tube can also be formed as a continuous form, as described, for example, in DE 197 47 623 A1. These continuous edges of the slots form a slot closing device which can be hooked into one another, the closing devices being brought into each other by snapping the corrugated tube sideways and snapped into one another. By pressing again, these continuous shut-off devices can be unhooked again or released and the corrugated tube opening is opened.

DE 197 05 761 A1 also discloses a corrugated pipe which has an overlap in the region of the slot extending in a straight line of the sheath, in which convex or concave waves are formed which are smaller than in the other corrugated pipe so that opposite edges with the longitudinal the slots can be brought into overlapping engagement by concave and convex waves.

One such overlapping region is also shown in DE 197 00 916 A1, each of which overlapping regions which overlap in the closed state of the corrugated tube and which have different wall thicknesses are formed here, respectively, to the left or right of the slot. The respective overlap regions are further characterized by a relatively complicated geometry, i.e. they require an equally complicated construction of a corrugated pipe shape in this overlap region. It can also be understood from this disclosure that the corrugated tube, when it has been provided with a slit in the formed overlap region, is so compressed that the respective overlap regions are displaced over each other, thereby causing a closure.

All of these described and known edge slot designs are relatively expensive to manufacture and often create difficulties in the production of such corrugated plastic tubes, especially in extrusion, when different wall thicknesses and / or undercuts are formed in a partial region of the tube circumference.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to improve the methods described above for manufacturing corrugated tubes with a longitudinal slot so that they can be easily performed so that the corrugated tube can be closed again in the simplest and hence fastest way In the case of curves or curves, it remained closed, but on the other hand, if necessary, it could be partially opened again, in order, for example, to repair a damaged section of the cable.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a shape-stable corrugated pipe consisting of plastic and designed in particular for protective wrapping of electrical conductors, with a slit opening extending along the sheath line according to the invention in which the corrugated pipe is convex waves and concave waves, cuts in a downstream cutting device along any straight line, the cutting guide being at a uniformly increasing or decreasing angle with respect to its inclination lying between the radius of the corrugated pipe or tangent to the corrugated pipe, such as the oblique cut, and the slit corrugated pipe is guided by a shaping device located downstream of the cutting device in which it is compressed such that the edges of the slit opening are offset from each other and immediately after the corrugated tube has cooled the inner edge of the slit opening is guided e outwards and is laid over the second, previously outwardly lying edge.

In the foregoing efforts to provide corrugated tubes with such longitudinal slit openings which, after insertion of the electrical cable, can be closed with both edges of the special closing means provided for this purpose, but can also be opened again, it has emerged that very expensive to form the edges of the longitudinal slot opening with special closing devices when the longitudinal slot opening is not guided radially, as in all known corrugated tubes, but is, as described above, guided as an oblique cut at a certain angle lying between the radial by cutting on one side or on the tangent to the pipe on the other. Since the corrugated pipe also has a resetting force also in the slit state due to the shape-stable plastic properties, the longitudinal slit opening also closes again after the cable has been inserted into the corrugated pipe. However, with the use of a radially extending longitudinal slot opening without a closing means formed especially at the edges of the longitudinal slot opening, there is a danger in the previously known corrugated tubes that the longitudinal slot opening is disposed in such curves or arcs with such a slot in curves or arcs. the interposed cables may exit the slot opening.

However, the formation of the slit opening according to the above described invention prevents such a full opening of the corrugated pipe with the elongated slit opening, especially in the curved areas, so that the inserted cables cannot protrude. By oblique cut, it is achieved that although the slot opening of course extends when the corrugated pipe is laid in the curves and curves and the edges of the corrugated pipe forming the slot open, the cable entry is still prevented because the oblique cut areas of convex and concave areas they overlap when their mutual distance is increased by laying the corrugated pipe in arcs and curves. Thus, the more flattened the cut is, the more the edges of the longitudinal slot opening may be separated and the interposed cables may not even exit the slot of the corrugated pipe, especially at the point of the curve and arc.

The compression of the corrugated tube shows that the diameter of the corrugated tube slightly decreases, but the edges of the slot opening overlap very wide. Thereby, the above-mentioned advantage is achieved that the slot opening can be opened especially in the areas of the curves, and the inserted electric cables do not even have to exit the corrugated pipe at the location of the slot opening.

By cooling the corrugated pipe, the plastic material from which the corrugated pipe is made gets its ultimate elasticity and flexibility, and thus now has properties that retain it constant shape stability due to the prescribed manufacturing process, i.e. the ability to regain its original shape also when forming in the longitudinal region. slot opening. By the above-described measure according to the invention, i.e. the return of the overlapping edges from their first position to the second, inverted position, the tube is provided with an evenly strong clamping force or corresponding closing and retaining abilities which are then retained even when the corrugated tube has to inserting the cable bundle, for example to repair the cable section, reopened. This high closing force generates convex waves and concave waves of the overlapping edges of the longitudinal slit opening closely into each other, thus creating a very smooth transition region in this slit opening region on both the inner and outer side of the corrugated tube with the slit opening.

The above-described invention, and in particular the surprising effects it has found, creates an advantage over prior art slit-hole pipes to the extent that they can be carried out on corrugated pipes which need not be shaped in the area of the housing in which the radially guided longitudinal rust. Thus, in the case of the pipe produced according to the invention, the special shaping of the region of the edges of the longitudinal slot opening into the closing means, or even in the present case, the additional placement of additional closing means, which is particularly inexpensive but also time-consuming.

The above-described object of the invention is also achieved for a plastic consisting of a shape-stable corrugated pipe with a slot opening extending along a sheath line, designed in particular for protective wrapping of electrical conductors which has a slot opening as a straight cut after extrusion and after convex waves and concave waves. along any sheath line at a steadily increasing or decreasing angle with respect to its inclination, lies between the radius of the corrugated pipe or tangent to the corrugated pipe, the slit corrugated pipe being compressed so that the edges of the slit aperture lie over each other and inside the lying edge of the slot opening is then led outwards and is laid over the second, previously outwardly lying edge.

In a further preferred embodiment, the corrugated pipe described above is located on the side of the formerly located edge spaced from the slit opening radially inwardly directed and running parallel to the opening. Such a projection extending parallel to the slot opening, when provided, gives the corrugated pipe a certain stiffness which, on the one hand, does not prevent the corrugated pipe from being laid in curves, but on the other hand restricts the corrugated pipe from squeezing. its connection with the manifolds at its attachment points imparts a higher resistance against pulling out of the manifold.

In a further preferred embodiment, the projection is in the form of a groove or notch. Such a projection increases the desired reinforcement of the corrugated pipe and stabilizes the closed position of the overlapping edges of the corrugated pipe hose.

Preferably, the groove-shaped fold or notch also has a corrugated profile of the wall of the corrugated pipe.

According to the invention, the second, previously laid out edge abuts with its edge against the projection opposite to that edge. This achieves that the relatively sharp edge formed within the lying edge of the corrugated pipe cannot damage the electrical conductors inserted into the corrugated pipe.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention described above is explained in more detail with reference to the preferred embodiments shown in the drawings. In the drawings, FIG. 1 shows a view of a section of convex and corrugated corrugated tube without a slot opening, with sections A-A and B-B respectively of a convex wave or a concave wave, FIG. 2 is a view of a section of convex and concave wines of a corrugated pipe with cross sections A-A and B-B respectively of convex or concave wave, the corrugated pipe having an oblique section, FIG. 3 is a view of a section of convex wines and concave wines of corrugated pipe, with sections AA and BB of convex wave or concave wave, respectively, showing a corrugated pipe with a slot opening having an oblique cut with overlapping edges of the slot opening, behind the cutting device, FIG. 4 shows a section of convex wines and concave wines of corrugated pipe, with sections AA or BB of convex wave or concave wave, respectively, after the inner edge lying previously below the second edge has been outwardly overlapped by the second edge lying outwardly and now reversed the overlapping edges of the slot opening with its convex waves and concave waves pressed together and FIG. 5 is a view of a section of convex and corrugated corrugated tube, with sections A-A and B-B respectively of convex or concave wave, according to FIG. 4, in which, however, in addition to the side of the outer edge now spaced apart from the slotted openings, the projection is directed radially and inwardly and runs parallel to the opening.

DETAILED DESCRIPTION OF THE INVENTION

The corrugated tube 7 shown in the figures is made of plastic and has convex waves 2 and concave waves 3 longitudinally spaced at certain distances. The plastic material used to produce such corrugated tubes is chosen by the person skilled in the art to give the corrugated tube the flexibility and flexibility necessary for it. shape stability so that it can be laid and held in a stable longitudinal direction on the one hand, but on the other hand it can be laid in curves and curves, the corrugated pipe having a slot opening once again opening and inserting the electric cable, the edges of the slot opening lie on top of each other again.

1 shows a corrugated tube drawn from a plastic extruder through a corrugator as shown in FIG. 2, is provided in the cutting device downstream of the crimping device with an oblique slit 4, wherein the slit 4 extending below the angular position between the radial section and the tangent to the corrugated tube is shown as shown in a side view of FIG. 2. As can be seen from these figures, the slope of the oblique slot may not be selected without limitation, but only up to the tangent position with respect to the inner region of the wall formed by concave waves in the inner space of the corrugated tube.

This slit-tube is then guided by a cutting device, which is also shown in the drawings, not shown in the drawings, the corrugated slit-tube according to FIG. 2, which has a certain diameter, decreases in diameter, while the edges 5 and 6, respectively, are displaced relative to one another, as shown in sections A-A or B-B in FIG. 3. It is clear that by pressing the corrugated tube 1, still warm during this shaping process, the edges 2 and 6 of the longitudinal slot opening 4 of the corrugated tube 2 are pushed further over one another, i.e. the exit of the electric cables inserted into such corrugated pipe.

The corrugated tube with the slit opening is then cooled, so that the plastic material from which the tube is made obtains its ultimate flexibility and flexibility, in particular shape stability. That is, the corrugated pipe tends to remain in the shape shown in FIG. 3, and if it is discharged from this predetermined shape, it automatically adjusts back to this predetermined shape as soon as it is released.

However, such a corrugated pipe is not yet suitable for its own purpose, namely to protect the electric cable inserted therefrom against damage, since in particular the edge 2 of the longitudinal slit opening protruding into the interior of the corrugated pipe 2 could damage the electric cable. For this reason, in a further process step, for example inside another processing device, possibly also manually, for example only when inserting electric conductors into such a corrugated tube, the edge 6 of the longitudinal slot opening lying in FIG. 3 von. This is achieved by the fact that the still lying edge 5 is pulled out, optionally removed, and is folded over the still lying edge 6, as shown in sections Ά-Ά and B-B in FIG. 4. In this treatment of the corrugated tube, the diameter of the corrugated tube again increases through the slot opening, and the corrugated tube thus formed could again assume an earlier smaller diameter due to its shape stability. As a result of this effort, convex waves and concave waves, as shown in FIG. 4, intensely into each other, so that a relatively smooth closure of the longitudinal slot opening 4 is formed, and in particular in the interior there is no longer any danger of damaging the electrical cables lying therein.

The longitudinal slit opening shown in FIG. 4 creates an excellent closing force in the corrugated tube 11 which in turn prevents the enclosed electrical cable from emerging from the corrugated tube 7 when the corrugated tube is laid in a small curve or in a very small curve and edge 5. or 6 of the longitudinal slot opening 4 should be slightly apart from each other.

5 finally shows a corrugated pipe according to the embodiment of FIG. 4, but which has a radially inwardly directed projection 7 extending parallel to the slot 4 in addition to the lateral edge of the lying edge 5 at a distance from the slot 4. This projection 7 could be simply formed as an under-running rib, but is preferably formed as a fold of the wall of the corrugated pipe 1 in the form of a notch or groove, as shown in FIG. 6. Such a longitudinally extending fold of the wall of the corrugated pipe gives it some intrinsic rigidity and, moreover, forms a stop on the sharp edges 2 of the edge 6 of the slot opening 4.

These stops prevent the corrugated tube from collapsing or compressing. This limits the shrinkage of the overlapping edges 5 and 6 of the slit 4 of the corrugated pipe, furthermore the stability of the corrugated pipe at the point of connection to the splitting pieces is increased and, in particular, a higher tearing resistance of the corrugated pipe is achieved. In particular, it is possible to avoid pulling out or falling out the ends of such corrugated pipes from the manifolds or the connections by accident.

The projection 2 ^{and the} abutment of the edge 9 of the edge 6 of the slot opening 8 also cause that the sharp edge 2 cannot damage the electrical cable inserted in the corrugated pipe.

Claims (6)

PATENT CLAIMS Method for producing a shape-stable corrugated pipe (1) consisting of plastic and designed in particular for protective wrapping of electric conductors, with a slot opening (4) running along the casing line, characterized in that the corrugated pipe (1) is then, when it has been extruded and provided with convex waves (2) and concave waves (3) in the crimping device, it cuts in a downstream cutting device along any straight line, the cutting guide being at a uniformly increasing or decreasing angle with respect to its inclination lies between the radius of the corrugated pipe or tangent to the corrugated pipe, i.e. as an oblique cut, and the slit corrugated pipe (1) is guided by a shaping device located downstream of the cutting device in which it is compressed so that the edges (5, 6) of the opening (4) are displaced relative to one another, and as soon as the corrugated tube has cooled down, the inside edge (5) of the slot opening The orifice (4) extends outwardly and is placed over the second, previously outwardly lying edge (6). Shape-stable corrugated pipe (1) consisting of plastic and designed in particular for the protective sheathing of electric cables, with a slot opening (4) running along the sheath line, characterized in that the slot opening (4) is formed after extrusion and convex the waves (2) and concave waves (3) along any sheath line at a uniformly rising or falling angle with respect to its inclination, lie between the radius of the corrugated pipe or tangent to the corrugated pipe, namely as a straight oblique cut, with the corrugated pipe ( 1) is compressed so that the edges (5) or (6) of the slot opening (4) lie over each other and the inside edge (5) is then directed outwards and is laid over the second, previously outwardly extending edge (6) ). Shaped corrugated pipe according to claim 2, characterized in that a projection (7) extending radially inwardly from the slot opening (4) and located parallel to the opening (4) extends laterally on the side of the edge (5) which is located earlier. ). Shaped corrugated pipe according to claim 3, characterized in that the projection (7) is formed as a fold (8) in the wall of the corrugated pipe (1) in the form of a notch or groove. Shaped corrugated pipe according to claim 4, characterized in that the groove (8) or groove (8) also has a corrugated profile of the wall of the corrugated pipe (1). Shaped corrugated pipe according to one of Claims 2 to 5, characterized in that the edge (6) which has been previously laid out abuts the projection (7) opposite the edge (6) with its edge (9).