CH720498A2 - One-piece cable protection pipe and method for its manufacture - Google Patents

Abstract

The invention relates to a one-piece cable protection pipe (2) made of plastic with a separating slot (4) running continuously in the longitudinal direction (A) and an associated longitudinal closure (6), wherein the longitudinal closure comprises two outer longitudinal ribs (8a, 8b) arranged on both sides of the separating slot, which are formed integrally with the cable protection pipe and protrude from its outer casing (10), wherein each longitudinal rib (8a, 8b) has a contact surface (12a, 12b) facing the other longitudinal rib (8b, 8a), which is formed complementarily to the contact surface (12b, 12a) of the other longitudinal rib, and wherein the longitudinal closure is optionally equipped with closure means in order to hold the two complementary contact surfaces together. The cable protection pipe including the separating slot (4) and the outer longitudinal ribs (8a, 8b) is produced by profile extrusion.

Description

Technical area

[0001] The invention relates to a one-piece cable protection pipe according to the preamble of patent claim 1, a method for its production and the use of this cable protection pipe for protecting a cable line.

State of the art

[0002] Cable protection pipes made of plastic with a longitudinal slot have been known for a long time and are described, for example, in patent documents CH 652 249 A5, FR 2621962 A3 and EP 2816686 A1. To form a new cable route or to repair or renew one, such cable protection pipes are laid and then the cables that have already been laid or provided are laid through the longitudinal slot into the interior of the cable protection pipes. The cable protection pipes are then radially closed with appropriate closure elements.

[0003] However, the known cable protection pipes have some disadvantages. In particular, during their manufacture, a correspondingly dimensioned tubular blank is produced, which is then provided with the required longitudinal slot using suitable cutting means. Depending on the design of the closure elements, the cable protection blank must be equipped with corresponding longitudinal beads or with projections arranged at longitudinal intervals along the longitudinal slot. This post-processing of the cable protection blank is not only suboptimal because of the additional work steps involved, but also because of the occurrence of stresses in the cable protection pipe produced.

Description of the invention

[0004] The present invention is based on the object of providing an improved cable protection pipe which is easier to manufacture with less material expenditure and no longer has any significant stresses, so that bending and spiral twisting of the pipe is prevented.

[0005] This object is achieved by a cable protection pipe having the features of patent claim 1, by a manufacturing method according to claim 11 and by a protected cable line according to claim 12.

[0006] The cable protection pipe according to the invention is made of plastic and has a continuous longitudinal slit and an associated longitudinal end, the longitudinal end comprising two outer longitudinal ribs arranged on both sides of the slit, which are integrally formed with the cable protection pipe and protrude from its outer casing. Each longitudinal rib has a contact surface facing the other longitudinal rib, which is complementary to the contact surface of the other longitudinal rib. Optionally, the longitudinal end is equipped with closure means to hold the two complementary contact surfaces together. This keeps the cable protection pipe in a closed state, as is provided in particular after the cable harness to be protected has been inserted. The cable protection pipe has an outer diameter that is selected from the range of 60 to 450 mm. The outer diameter refers to areas of the cable protection pipe without a longitudinal end.

[0007] Because the cable protection pipe, including the originally formed separating slot not created by cutting and the outer longitudinal ribs, is manufactured by profile extrusion, it can be manufactured comparatively inexpensively and is largely free of undesirable stresses.

[0008] In the production of plastic semi-finished products by extrusion, an extrusion plant is generally used which has an extruder, an extrusion tool and downstream equipment.

[0009] The plastic to be processed influences the choice of extruder (in particular single-screw or twin-screw extruder) and its components (geometry of the screw(s) and the plasticizing cylinder).

[0010] The desired shape of the extrudate influences both the extrusion tool and the downstream equipment. When it comes to extrusion tools, a distinction is made between tools with an annular gap-shaped outlet (e.g. for pipes), profile tools (e.g. for window profiles) and film and plate tools. The structure of these extrusion tools differs considerably not only in the geometry of the outlet, but also in the overall structure and fluid dynamics. The extrusion tool is normally followed by a calibration and cooling section. This is where there is a big difference between pipe and profile extrusion. While a simple calibration sleeve (for calibrating the outside diameter) is sufficient for pipe extrusion, a calibration table with a complex calibrator (for calibrating all dimensions) is used for profile extrusion. A dry or wet calibrator or a combination of these can be used as a calibrator. In certain applications (e.g. in the production of dimensionally stable profiles made of polyolefins) it may be useful to operate a water-wetting pre-calibrator followed by a dry calibrator.

[0011] The term "complementary" mentioned in connection with the longitudinal ribs is to be understood in such a way that when the longitudinal ribs are brought together by a force acting in the tangential direction to the separating slot, the relevant contact surfaces come into contact with one another and in the process an at least linear, in particular a flat, contact zone running in the longitudinal direction is formed between the two longitudinal ribs.

[0012] In some embodiments, the longitudinal closure is provided with closure means to hold the two contact surfaces together.

[0013] In the method according to the invention for producing a cable protection pipe according to the invention, an extrusion device is used which comprises a filling area, an extrusion tool and a calibrator in succession, whereby plastic fed into the filling area is advanced in the working direction in the extrusion tool and melted and is then formed in the calibrator into a profile shape corresponding to the cable protection pipe including the separating slot and the outer longitudinal ribs. As a rule, this forms a pipe which is essentially cylindrical with the exception of the longitudinal end and the longitudinal slot running therein.

[0014] Preferred embodiments of the cable protection pipe are defined in the dependent claims.

[0015] Terms such as “cylindrical”, “longitudinal”, “tangential” and “radial” are not to be understood in a strictly geometric sense, but in any case within the framework of the tolerances applicable to cable protection pipes.

[0016] The dimensions and material selection of the various components depend on the intended purpose and also on the products available in the field. In other words, the cable protection pipe must be designed in a basically weatherproof form suitable for use on construction sites. The mechanical load-bearing capacity must correspond to the weights required when laying it underground.

[0017] There are numerous possibilities with regard to the shape of the two complementary contact surfaces. According to a first embodiment (claim 2), the two complementary contact surfaces are essentially planar and are aligned in such a way that they are parallel to one another when the longitudinal ribs are brought together. In order to hold the contact surfaces together in this embodiment, appropriate closure means must be provided. These can in particular be clamps that are attached at a distance from one another in the longitudinal direction of the tube. In principle, however, plug-in pins can also be provided, which would be inserted into previously made tangential holes in the longitudinal ribs.

[0018] In a further embodiment (claim 3), the closure means are implemented by a shape of the two complementary contact surfaces that interact in a locking manner. In certain embodiments (claim 4), the two complementary contact surfaces also have a shape that can be disengaged. There are many possible ways of implementing this, with a convexly shaped active element and a concavely shaped active element usually interacting. It goes without saying that the dimensions of such active elements must be selected depending on their material properties, in particular elasticity, so that at least a locking and, if desired, also a disengaging is possible.

[0019] In certain embodiments (claim 5), each longitudinal rib is mushroom-shaped on the side facing away from the contact surface with a comparatively thin foot region and a comparatively thick head region located radially further out. Such an embodiment is particularly suitable for the attachment of overlapping closure elements.

[0020] As already mentioned, the fundamentally known requirements for a cable protection pipe made of plastic must be taken into account when selecting the material. According to an advantageous embodiment (claim 6), the plastic is a polyolefin, preferably a polyethylene or a polyethylene blend or a polyethylene copolymer.

[0021] The dimensions of the cable protection pipe can be selected from a wide range and depend on the intended use. For the wall thickness, it is expedient to select this from the range of 2 to 15 mm, preferably from 4 to 7 mm (claim 7).

[0022] Although there is no absolute limit to the length of the profile-extruded cable protection pipe according to the invention, it is expedient, particularly for transport reasons, to provide a length of 2 to 15 m, preferably 5 to 12 m (claim 8).

[0023] In certain embodiments of the cable protection pipe (claim 9), this is provided with grooves running in the longitudinal direction. This achieves a comparatively greater flexibility with regard to the opening and closing of the separating slot for a given overall mechanical load capacity.

[0024] In further embodiments (claim 10), when the separating slot is not closed, the contact surfaces are spaced apart and form an opening angle of 5° to 120°, preferably 15° to 60°. Such a cable protection pipe can be kept in the open state during installation or can be brought into the open state after installation, then remains in this state until the required cables have been inserted and is finally brought into the closed state.

[0025] A further aspect of the invention (claim 12) relates to a protected cable line with a first line end and a second line end, wherein the first line end is connected to an associated first connection point, and wherein the second line end is connected to an associated second connection point, wherein the first connection point and the second connection point are located at spaced-apart points on the ground, wherein at least one part of the cable line located outdoors is accommodated in a cable protection pipe according to the invention.

Short description of the drawings

[0026] Embodiments of the invention are described in more detail below with reference to the drawings, in which: Fig. 1 shows a first example of a cable protection pipe, in the open state, in a perspective view, Fig. 2 shows the cable protection pipe of Fig. 1 in the closed state, in a perspective view, Fig. 3 shows a second example of a cable protection pipe, in the open state, in a perspective view, Fig. 4 shows the cable protection pipe of Fig. 3, namely (a) in the partially opened state, and (b) in the further opened state, each in a cross-sectional view, Fig. 5 shows a third example of a cable protection pipe, in the open state, in a perspective view, and Figs. 6 to 9 show various embodiments of the closure means, each as a detail and each in a cross-sectional view, Fig. 10 in a perspective view, (a) a cable protection pipe arranged next to a railway track along the same, and (b) a protected cable line formed with the cable protection pipe of (a), and Fig. 11 in perspective view, (a) two coaxially arranged, spaced-apart cable protection pipes and a connecting sleeve arranged between them, and (b) the cable protection pipes of (a) each inserted at their ends into the connecting sleeve.

Ways to implement the invention

[0027] In the following text and in the associated figures, functionally identical elements are designated by the same reference numerals and are therefore not explained again in each subsequent figure.

[0028] The cable protection tube 2 shown in Figures 1 and 2 has a separating slot 4 running in the longitudinal direction L of the cable protection tube and an associated longitudinal end 6. The longitudinal end comprises two outer longitudinal ribs 8a and 8b arranged on both sides of the separating slot 4, which are formed in one piece with the cable protection tube due to the production by means of profile extrusion. As can be seen from the figures, the longitudinal ribs 8a and 8b are formed so as to protrude from the outer casing 10 of the cable protection tube.

[0029] Each longitudinal rib 8a, 8b comprises a contact surface 12a or 12b facing the other longitudinal rib 8b, 8a, which is designed to be complementary to the corresponding contact surface 12b, 12a of the other longitudinal rib 8b, 8a. In the embodiment shown, the two complementary contact surfaces 12a or 12b are essentially planar and are aligned such that they are parallel to one another when the two longitudinal ribs are brought together.

[0030] In certain embodiments, which are not illustrated here, the longitudinal closure 6 is equipped with detachable closure means in order to hold the two complementary contact surfaces 12a, 12b together. These can in particular be clamps which are to be attached at a distance from one another in the longitudinal direction of the tube. In principle, however, plug-in pins can also be provided which would be inserted into previously made tangential holes in the longitudinal ribs.

[0031] A further embodiment of the cable protection pipe according to the invention is shown in Fig. 3 and 4a, 4b. The longitudinal end in cross section is designed as follows: each longitudinal rib 8a, 8b is mushroom-shaped on the side facing away from the contact surface 12a, 12b with a foot region 14 that is comparatively thin in the tangential direction and a head region 16 that is comparatively thick in the tangential direction. As can be seen from Fig. 3 and 4a, 4b, the foot region 14 borders radially on the outer casing 10, while the head region 16 is located radially further outwards in this respect. Such a shape is particularly suitable for attaching overlapping clamps that act as a closure means.

[0032] In the embodiment shown in Fig. 3 and 4a, 4b, the two complementary contact surfaces (12a, 12b) have a shape that interacts in a locking manner. This will be explained in more detail later in connection with Fig. 6 to 9. However, the features of Fig. 3 and 4a, 4b explained above can basically be used independently of the selected shape of the contact surfaces 12a, 12b and are particularly useful for planar contact surfaces.

[0033] In Fig. 4a and 4b, the cable protection tube is shown in the open state, wherein the contact surfaces 12a, 12b are spaced apart from each other and form an opening angle α of 12° and 70°, respectively.

[0034] A further embodiment is shown in Fig. 5. The cable protection tube 2 is provided with five grooves 18 running in the longitudinal direction.

[0035] Various embodiments of closure means with a shape that interacts in a locking manner are shown in Figures 6 to 9. In principle, this is achieved in that one contact surface 12a has a concave region into which a suitably convexly shaped region of the other contact surface 12b can be locked.

[0036] In the variants of Fig. 6 and 7, the shape can be disengaged, i.e. the cable protection tube can be repeatedly switched between the open and closed state.

[0037] In contrast, in the variants of Figs. 8 and 9, disengagement is deliberately prevented, so that a closed cable protection tube can only be opened by damaging measures such as cutting, tearing or melting.

[0038] The dimensions of the cable protection pipe can be selected from a wide range. In particular, the external diameter D can be selected from the range of 60 to 450 mm. For the wall thickness d, it is expedient to select this from the range of 2 to 15 mm, preferably from 4 to 7 mm.

[0039] In the schematic example of Fig. 10a and 10b, a cable protection pipe 2 according to the invention is arranged directly next to a railway track 22; this corresponds to a typical application. In Fig. 10a, a single cable protection pipe with an open longitudinal slot has been laid out. In Fig. 10b, a cable line 20 with line ends E1 and E2, which are connected to associated connection points A1 and A2, is located in the protective interior of the cable protection pipe. Fig. 11a and 11b illustrate the connection of individual cable protection pipes 2A and 2B by means of a basically known connecting sleeve 24, which can be reversibly closed with closure elements 26.

List of reference symbols

[0040] 2, 2A, 2B Cable protection pipe 4 Separating slot 6 Longitudinal end 8a, 8b Longitudinal ribs 10 Outer casing of 2 12a, 12b Contact surfaces 14 Foot area of 8a, 8b 16 Head area of 8a, 8b 18 Longitudinal grooves 20 Cable line 22 Railway track 24 Connecting sleeve 26 Closure elements A Longitudinal direction D Outside diameter of 2 d Wall thickness of 2 α Opening angle

Claims (12)

1. One-piece cable protection pipe (2) made of plastic with a separating slot (4) running continuously in the longitudinal direction (A) and an associated longitudinal end (6), wherein the longitudinal end comprises two outer longitudinal ribs (8a, 8b) arranged on both sides of the separating slot, which are formed integrally with the cable protection pipe and protrude from its outer casing (10), wherein each longitudinal rib (8a, 8b) has a contact surface (12a, 12b) facing the other longitudinal rib (8b, 8a), which is formed complementarily to the contact surface (12b, 12a) of the other longitudinal rib, and wherein the longitudinal end is optionally equipped with closure means in order to hold the two complementary contact surfaces together, wherein the cable protection pipe has an outer diameter (D) which is selected from the range from 60 to 450 mm, characterized in that the cable protection pipe including the separating slot (4) and the outer longitudinal ribs (8a, 8b) are produced by profile extrusion. 2. Cable protection pipe according to claim 1, wherein the two complementary contact surfaces (12a, 12b) are substantially planar. 3. Cable protection pipe according to claim 1, wherein the closure means are realized by a locking cooperating shape of the two complementary contact surfaces (12a, 12b). 4. Cable protection pipe according to claim 3, wherein the closure means are releasable in that the two complementary contact surfaces (12a, 12b) have a disengageable shape. 5. Cable protection pipe according to one of claims 2 to 4, wherein each longitudinal rib (8a, 8b) is mushroom-shaped on the side facing away from the contact surface (12a, 12b) with a comparatively thin foot region (14a, 14b) and a comparatively thick head region (16a, 16b). 6. Cable protection pipe according to one of claims 1 to 5, wherein the plastic is a polyolefin, preferably a polyethylene or a polyethylene blend or a polyethylene copolymer. 7. Cable protection pipe according to one of claims 1 to 6, wherein it has a wall thickness (d) selected from the range from 2 to 15 mm, preferably from 4 to 7 mm. 8. Cable protection pipe according to one of claims 1 to 7, which has a length of 2 to 15 m, preferably 5 to 12 m. 9. Cable protection pipe according to one of claims 1 to 8, which is provided with grooves (18) running in the longitudinal direction. 10. Cable protection pipe according to one of claims 1 to 9, in which in the unlocked state of the separating slot the contact surfaces are spaced apart and thereby form an opening angle (α) of 5° to 120°, preferably of 15° to 60. 11. A method for producing a cable protection pipe according to one of claims 1 to 10 by profile extrusion of the plastic by means of an extrusion device, wherein the extrusion device comprises in succession a filling area, an extrusion tool and a calibrator, wherein plastic fed into the filling area is advanced in the working direction in the extrusion tool and melted and is then formed in the calibrator into a profile shape corresponding to the cable protection pipe including the separating slot and the outer longitudinal ribs. 12. Protected cable line (20), with a first line end (E1) and a second line end (E2), wherein the first line end (E1) is connected to an associated first connection point (A1), and wherein the second line end (E2) is connected to an associated second connection point (A2), wherein the first connection point (A1) and the second connection point (A2) are located at spaced-apart points on the ground, characterized in that at least a part of the cable line located outdoors is accommodated in a cable protection pipe (2) according to one of claims 1 to 10.