SELF-CLOSING FOIL SHEATHING AND METHOD OF MAKING THE SAME

Abstract

A method for producing a self-closing foil sheathing (14) wound onto at least one line (10) of a cable arrangement (12) includes providing an elastically deformable foil strip (16) which, in a load-free or bare state, is bent in a plane of the foil strip (16). The foil strip (16) is wound onto the line (10) in order to form the foil sheathing (14) which surrounds the line (10). The foil strip (16) during winding onto the line (10) is elastically deformed radially to the outside and in this way is subjected to radial loading in the direction of the line (10).

Claims

1. A method for producing a self-closing foil sheathing which is wound on at least one conductor of a cable arrangement, comprising the steps: providing a resiliently deformable foil strip which in an unloaded or exposed state is curved in a plane of the foil strip; and winding the foil strip onto the conductor in order to form the foil sheathing enclosing the conductor, wherein the foil strip forming the foil sheathing, in a state in which it is wound on the conductor, is resiliently deformed radially outwards and thus radially loaded in the direction of the conductor.

2. The method as claimed in claim 1, in which the resiliently deformable foil strip in the unloaded or exposed state forms a tubular body which has a smaller diameter as compared to the conductor.

3. The method as claimed in claim 1, in which the foil strip comprises a plastics material, in particular polyethylene terephthalate or polypropylene.

4. The method as claimed in claim 1, in which the foil strip is in multilayer form and comprises a first insulating layer of a plastics material, in particular polyethylene terephthalate or polypropylene, and a second conducting layer of a metallic material, in particular aluminum.

5. The method as claimed in claim 1, which further comprises a step of plastic deformation of a foil strip pre-product to produce the foil strip curved in its plane, in that a portion of the foil strip pre-product that is to be wound on the at least one conductor is moved with a face that is to be placed on the conductor over a shaping edge of a shaping tool.

6. The method as claimed in claim 5, wherein, in the step of plastic deformation of the foil strip pre-product, a normal force acting on the foil strip pre-product in the direction of the shaping edge is applied.

7. The method as claimed in claim 6, wherein the normal force acting on the foil strip pre-product in the direction of the shaping edge is variably adjustable in dependence on the curve that is to be formed in the plane of the foil strip, in particular in dependence on a radius of curvature that is to be formed.

8. The method as claimed in claim 5, wherein an edge angle and/or an edge radius of the shaping edge of the shaping tool is variably adjustable in dependence on the curve that is to be formed in the plane of the foil strip, in particular in dependence on a radius of curvature that is to be formed.

9. The method as claimed in claim 5, in which, in the step of plastic deformation of the foil strip pre-product, the foil strip pre-product is moved relative to the shaping edge in such a manner that an angle between the shaping edge and a direction of movement of the foil strip pre-product at the shaping edge has a value between 90 and 20, preferably 90 or 45.

10. The method as claimed in claim 9, wherein the angle between the shaping edge and the direction of movement of the foil strip pre-product at the shaping edge is variably adjustable in dependence on the curve that is to be formed in the plane of the foil strip, in particular in dependence on a direction of curvature that is to be formed.

11. The method as claimed in claim 9, wherein the angle between the shaping edge and the direction of movement of the foil strip pre-product at the shaping edge is so adjusted that it corresponds to a pitch angle of the foil strip in the state in which it is wound on the conductor.

12. The method as claimed in claim 1, wherein the step of winding the foil strip on the conductor is carried out in such a manner that the foil strip is wound on the conductor longitudinally or spirally, and wherein in particular edge regions of the foil strip overlap in the wound state.

13. A cable arrangement having at least one conductor and a self-closing foil sheathing wound around the conductor, wherein a foil strip forming the foil sheathing, in a state in which it is wound on the conductor, is resiliently deformed radially outwards and thus radially loaded in the direction of the conductor.

14. A shaping tool for producing a foil strip forming a self-closing foil sheathing in a cable arrangement, which shaping tool has a base body with at least two shaping edges formed on its lateral surface and is adapted selectively to position one of the shaping edges in such a manner that a foil strip pre-product can be moved over that shaping edge in order to produce the foil strip by means of plastic deformation of the foil strip pre-product, wherein the foil strip is resiliently deformable and, in an unloaded or exposed state, is curved in a plane of the foil strip.

15. The shaping tool as claimed in claim 14, wherein the base body is prism-shaped and has at least three shaping edges formed on the lateral surface thereof.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The present disclosure is to be explained further by means of figures. These figures show, in schematic form:

[0037] FIGS. 1 to 4 a method for producing a self-closing foil sheathing wound on at least one conductor of a cable arrangement,

[0038] FIG. 5 a cable arrangement comprising a self-closing foil sheathing, and

[0039] FIG. 6 a shaping tool for producing a self-closing foil sheathing.

DETAILED DESCRIPTION

[0040] A method for producing a self-closing foil sheathing 14 wound on at least one conductor 10 of a cable arrangement 12, as shown in FIG. 4, is described hereinbelow with reference to FIGS. 1 to 4.

[0041] In a first step of the method, a resiliently deformable foil strip 16 which in an unloaded or exposed state is curved in a plane of the foil strip 16 is provided. FIGS. 1 and 2 illustrate this method step, wherein FIG. 1 is a perspective view of an apparatus 18 for providing the foil strip 16 and FIG. 2 is a plan view of the apparatus shown in FIG. 1.

[0042] FIG. 3 shows a foil strip 16 provided by means of the apparatus 18 in an exposed state. In this state, the foil strip 16 forms a tubular body 20. More specifically, the foil strip 16 in the exposed state is arranged in the form of a spiral, wherein the foil strip 16 forms a lateral surface of the tubular body 20. The cross-section of the tubular body 20 is substantially provided with a circular outer contour.

[0043] The tubular body 20 has, in cross-section, a smaller diameter compared to the at least one conductor 10. More specifically, the tubular base body 20 has a substantially constant outside diameter D.sub.1 which is smaller than an outside diameter D.sub.2 of the conductor 10. It can thus be ensured that, when the foil strip 16 is in the state wound on the conductor 10, as shown in FIG. 4, the foil strip 16 is resiliently deformed as compared to the unloaded or exposed state, and a holding force F.sub.H induced by that deformation thus acts on the foil sheathing 14 formed by the foil strip 16.

[0044] The method step of providing the foil strip 16 will be described in greater detail hereinbelow with reference to FIGS. 1 and 2. The provision of the foil strip 16 is carried out by a step of plastic deformation of a foil strip pre-product 16. The plastic deformation of the foil strip pre-product 16 is carried out in such a manner that a portion of the foil strip pre-product 16 that is to be wound on the conductor 10 is moved with a face that is to be placed on the conductor over a shaping edge 22 of a shaping tool 24. The shaping edge 22 of the shaping tool 24 is in the form of a sharp edge and has an edge angle of 60.

[0045] The method step of plastic deformation of the foil strip pre-product 16 performed by means of the apparatus 18 is carried out continuously. For this purpose, the foil strip pre-product 16 is unwound from a supply roll, not shown here, and moved over the shaping edge 22 by means of deflecting rollers 26. The foil strip pre-product 16 is thereby subjected to a normal force F.sub.N acting in the direction of the shaping edge 22. The normal force F.sub.N acting on the foil strip pre-product 16 in the direction of the shaping edge 22 is variably adjustable in dependence on the curve that is to be formed in the plane of the foil strip 16, in particular in dependence on a radius of curvature of the curve that is to be formed. This can be carried out, for example, in that the shaping tool 24 is moved upwards or downwards along its vertical axis Z relative to the deflecting rollers 26.

[0046] For adjusting a desired curve in the plane of the foil strip 16, it can additionally be provided that the geometric form of the shaping edge 22 is adjustable. In particular, an edge radius and/or an edge angle of the shaping edge 22 can correspondingly be adjusted. For this purpose, a shaping tool 24 having multiple shaping edges 22 can be provided, as shown in FIG. 6, wherein the foil strip pre-product 16 is selectively moved over one of the multiple edges 22. In the present case, the shaping tool 24 has a linear shaping edge 22, which is adapted in particular for producing a single curve in the plane of the foil strip 16. In a further embodiment, the shaping tool 24 has different radii at the multiple, for example three, edges 22. One shaping tool can thus be used for different foils on which the different radii are established.

[0047] The step of plastic deformation of the foil strip pre-product 16 is carried out in such a manner that the foil strip pre-product 16 is moved relative to the shaping edge 22 in such a manner that an angle W between the shaping edge 22 and a direction of movement A of the foil strip pre-product 16 at the shaping edge 22 has a value of approximately 45. An angle of approximately 45 is advantageous in view of the frequency range often present in such conductors. In the apparatus 18 shown in the present case, the angle W between the shaping edge 22 and the direction of movement A of the foil strip pre-product 16 is variably adjustable in dependence on the curve that is to be formed in the plane of the foil strip 16, in particular in dependence on a direction of curvature relative to the foil strip 16 that is to be formed. This can be achieved by a pivoting movement of the shaping tool 24 about its vertical axis Z relative to the foil strip pre-product 16, as indicated in FIG. 1 by an arrow B. The adjustment of the angle W is carried out in particular in dependence on a pitch angle S of the foil strip 16 in the state in which it is wound on the conductor 10, as shown in FIG. 4. More specifically, the angle W between the shaping edge 22 and the direction of movement A of the foil strip pre-product 16 is so adjusted that it corresponds substantially to the pitch angle S of the foil strip 16 in the state in which it is wound on the conductor 106.

[0048] The method step shown in FIGS. 1 and 2 makes it possible for the portion of the foil strip 16 that is to be wound on the conductor 10 to have a substantially constant curve in its exposed state. In other words, as shown in FIG. 3, the portion of the foil strip 16 that is to be applied is provided throughout with a curve in its plane along the same axis of curvature and with a substantially constant radius of curvature. The axis of curvature here corresponds to the longitudinal axis of the tubular body 20.

[0049] In the method shown here, the foil strip 16, and accordingly the foil strip pre-product 16, is in multilayer form, wherein a first layer comprises a plastics material, in particular polyethylene terephthalate, and a second layer comprises a metallic material, in particular aluminum. The step of plastic deformation of the foil strip pre-product 16 is thereby performed in such a manner that the first layer is guided over the shaping edge 22 in contact therewith.

[0050] In a further step of the method, the foil strip 16 provided is wound onto the at least one conductor 10 in order to form the foil sheathing 14 enclosing the at least one conductor. This is carried out in such a manner that the foil strip 16 forming the foil sheathing 14, in a state in which it is wound on the conductor 10, is resiliently deformed radially outwards and thus radially loaded in the direction of the conductor 10. In other words, in the state wound on the conductor 10, the foil sheathing 14 is acted upon by the holding force F.sub.H induced by the resilient deflection or deformation thereof. This has the effect of pressing the foil sheathing 14 against the conductor 10 so that it is held in a self-closing manner on the conductor 10 in the wound position.

[0051] The step of winding the foil strip 16 onto the conductor 10 is carried out in such a manner that the foil strip 16 is spirally wound on the conductor 10. The wound foil strip has a pitch angle of approximately 45. In order to produce a closed foil sheathing 14, winding is further carried out in such a manner that edge regions of the foil strip 16 overlap in the wound state.

[0052] FIG. 5 shows a cable arrangement 12 in the form of a STP (shielded twisted pair) cable with exposed conductor strands. The cable arrangement 10 comprises multiple single conductors 10, which are stranded in pairs and shielded by means of a foil shield. The foil shield around in each case two stranded single conductors 10 has been produced by means of the method described hereinbefore. The foil shield is thereby formed by the foil strip 16 constituting the self-closing foil sheathing 14. In the wound state, the foil strip 16 is resiliently deformed radially outwards and thus radially loaded in the direction of the single conductors 10.

[0053] FIG. 6 shows a shaping tool 24 for producing the foil strip 16 forming the self-closing foil sheathing 14. The shaping tool 24 has a prism-shaped base body 34 with three shaping edges 22 formed on the lateral surface thereof. The prism-shaped base body 34 comprises a base in the form of an equilateral triangle. The shaping tool is adapted selectively to position one of the shaping edges 22 in such a manner that the foil strip pre-product 16 can be moved over that shaping edge in order to produce the foil strip 16 by means of plastic deformation of the foil strip pre-product 16. The foil strip 16 so produced is resiliently deformable and, in an unloaded or exposed state, is curved in a plane of the foil strip 16. The shaping tool 24 shown here can be used in the method step shown in FIGS. 1 and 2. In order selectively to position one of the shaping edges relative to the foil strip pre-product 16 that is to be deformed, the shaping tool 24 is preferably adapted to be pivoted about its longitudinal axis L.