Method For Removing A Cable Film

Abstract

A method for easy, safe and fast removal of a section of a cable film. An end section of a cable has a cable axis, wherein the cable includes a cable jacket and at least one electrically conductive conductor structure and which includes a cable film made from a plastic and applied into one of the conductor structures. A defined damaged region is generated by inductively heating at least that conductor structure on which the cable film is applied such that the cable film applied onto the heated conductor structure is at least partially thermally damaged in the damaged region. The cable film is moved relative to one of the conductor structures, wherein a crack is formed by the relative movement in the damaged region that separates the section of the cable film to be removed from a section of the cable film remaining on the cable.

Claims

1. A method for removing a section of a cable film from an end section of a cable, comprising the following: provide an end section of a cable having a cable axis, wherein the cable comprises a cable jacket and at least one electrically conductive conductor structure and which includes a cable film made from a plastic and applied onto one of the conductor structures; generate a defined damaged region in the provided end section by inductively heating at least that conductor structure on which the cable film is applied such that the cable film applied onto the heated conductor structure is at least partially thermally damaged in the damaged region; move the cable film relative to one of the conductor structures, wherein a crack is formed by the relative movement in the damaged region that separates the section of the cable film to be removed from a section of the cable film remaining on the cable.

2. The method according to claim 1, wherein the at least one conductor structure consists of an inner conductor and at least one outer conductor structure, wherein the cable film is applied to one of the outer conductor structures.

3. The method according to claim 2, wherein the outer conductor structure onto which the cable film is applied is formed as a metal film.

4. The method according to claim 3, wherein the outer conductor structure embodied as a metal film is structurally weakened by the inductive heating in the damaged region.

5. The method according to claim 1, wherein the inductive heating is carried out by an inductive coil, by which inductive coil an electromagnetic alternating field is generated, wherein at least the damaged region of the cable is arranged inside the inductive coil during the inductive heating.

6. The method according to claim 1, wherein the cable film in the damaged region is covered by the cable jacket during the inductive heating of the at least one conductor structure.

7. The method according to claim 1, wherein the method further comprises the following: at least partially circumferentially cutting the cable jacket in a position that is arranged closer to a cable end of the end section than the damaged region.

8. The method according to claim 7, wherein the cable jacket is cut at least partially circumferentially during or after the defined damaged region is generated.

9. The method according to claim 7, wherein the cable jacket is cut at least partially circumferentially before the defined damaged region is generated.

10. The method according to claim 7, wherein the crack formed by the relative movement forms in the cable film beneath the cable jacket.

11. The method according to claim 1, wherein the cable jacket is divided into a section of the cable jacket to be removed and a remaining section of the cable jacket by an at least partially circumferential cut, and the section of the cable jacket to be removed is moved in the direction of the cable axis, wherein the section of the cable film to be removed, which is at least partially attached to the cable jacket, is stripped by the movement.

12. The method according to claim 1, wherein the following are performed in a processing space of a processing device: inductive heating of at least that conductor structure on which the cable film is applied; at least partially circumferential cutting of the cable jacket; jointly removing a section of the cable jacket and the section of the cable film to be removed.

13. The method according to claim 1, wherein the at least one conductor structure onto which the cable film is applied is inductively heated to a temperature of greater than or equal to 80° C.

14. A processing device for performing a method according to claim 1, comprising: a processing space for accommodating an end section of a cable to be processed, wherein the cable comprises a cable jacket and at least one electrically conductive conductor structure and a cable film made of a plastic and applied on one of the conductor structures; an induction coil arranged in the processing space, which induction coil is configured to inductively heat at least that conductor structure of a section of the cable located in the induction coil during a processing operation on which conductor structure the cable film is applied, such that the cable film applied on the heated conductor structure is at least partially thermally damaged in a defined damaged region, to determine that position of the cable on which a crack forms in the cable film upon subsequent stripping; a stripper for stripping a section of the cable film defined by the damaged region to be removed.

15. The processing device according to claim 14, wherein at least one clamping unit is arranged in the processing space for fixing the end section of the cable during a processing operation.

16. The processing device according to claim 14, wherein the processing device further comprises a cutting unit for at least partially circumferentially cutting the cable jacket of the cable.

17. The processing device according to claim 16, wherein the cutting unit is arranged in the processing space.

18. The processing device according to claim 17, wherein the processing space has an insertion opening for inserting the end section of the cable into the processing space and the induction coil is arranged between the cutting unit and the insertion opening.

19. The processing device according to claim 17, wherein the cutting unit is arranged in the processing space relative to the induction coil such that the at least partially circumferential cut of the cable jacket of the cable can be produced at a position that is arranged closer to a cable end of the end section than the damaged region that can be generated by the induction coil.

20. The processing device according to claim 14, where in the stripper means for stripping the section of the cable film to be removed is formed to contact a section of the cable jacket to be removed and defined by a cut and to subsequently remove the section of the cable jacket together with a section of the cable film to be removed by a stripping motion.

21. The processing device according to claim 14, wherein the stripper for stripping the section of the cable film to be removed is arranged in the processing space.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0065] The present teaching is now explained in more detail with reference to design examples. The drawings are exemplary and while they are designed to illustrate the idea of the present teaching, they are in no way intended to narrow or even conclusively reproduce the idea of the present teaching.

[0066] FIGS. 1a to 1c illustrate the schematic sequence of the method according to the present teaching based on an end section of a first design example of a cable;

[0067] FIGS. 2a to 2c illustrate the schematic sequence of the method according to the present teaching based on the end section of a second design example of the cable;

[0068] FIGS. 3a to 3c illustrate the schematic sequence of the method according to the present teaching based on the end section of a third design example of the cable;

[0069] FIG. 4 illustrates an end section of the cable in a processing device;

[0070] FIG. 5 illustrates the end section of the cable in the processing device after the inductive heating;

[0071] FIG. 6 illustrates the end section of the cable after cutting;

[0072] FIG. 7 illustrates the end section of the cable in the processing device during stripping.

DETAILED DESCRIPTION

[0073] FIGS. 1a to 1c show the steps of the method according to the present teaching in a chronological sequence using the example of a first design example of a cable 1. In the first design example, the cable 1 comprises a conductor structure 3 designed as an inner conductor 4 and an outer cable jacket 7, wherein a cable film 6, which is made of a plastic, is arranged between the inner conductor 4 and cable jacket 7. The cable film 6 is applied correspondingly to the conductor structure 3 embodied as an inner conductor 4. The cable 1 also has a cable axis 2, which represents a symmetry axis for the cable structure.

[0074] Here, an end section 1b of the cable 1 is shown, in which a section 6a of the cable film 6 to be removed from the inner conductor 4 is to be removed in order to expose a section of the inner conductor 4. The end section 1b of the cable 1 is arranged in sections within an induction coil 12 in order to be able to perform the inductive heat treatment described below.

[0075] In the present design example, as shown in FIG. 1a, cable jacket 7 already at the beginning of the procedure has a cut 9 in the end section 1b that divides the cable jacket 7 into a section 7a (see FIG. 1b) and a remaining section 7b.

[0076] FIG. 1b shows the end section 1b during or immediately after the inductive heat treatment by means of the induction coil 12. The inner conductor 4, i.e. the conductor structure 3 on which the cable film 6 is applied, is inductively heated using the induction coil 12. Due to the heating of the inner conductor 4 in a defined region, the cable film 6 is thermally damaged in an appropriately defined damaged region S.

[0077] The thermal damage can be, for example, a local surface melting, through-melting, or melting the plastic off the cable film 6 in the damaged region S, in particular if it is a thermoplastic. It is also conceivable that the plastic of the cable film 6 is burned off, degraded or embrittled in the damaged region S due to the thermal damage, in particular if it is a not a thermoplastic.

[0078] The thermal damage to the cable film 6 in the damaged region S defines an area where a crack forms during a movement of the cable film 6 relative to the inner conductor 4, said crack dividing the cable film 6 into a section 6a to be removed and a remaining section 6b.

[0079] Due to the crack defined by the damaged region S, the section 6a of the cable film 6 to be removed can be removed from the conductor structure 3 located thereunder, namely the inner conductor 4, without leaving any residue of the cable film 6 in the area of the inner conductor 4 to be exposed.

[0080] The end section 1b is delimited at one end by a cable end 1a, i.e. an end face of the cable 1. The end of the end section 1b opposite the cable end can coincide with the cut 9 and/or the damaged region S or can still comprise a section of the cable 1 where the remaining section 7a of the cable jacket 7 is arranged.

[0081] In the present design example, the cut 9 in the cable jacket 7 is arranged closer to the cable end 1a than the damaged region S, so that the cable jacket 7 is intact in that section of cable 1 located inside the induction coil 12 during the inductive heat treatment. Since the heat treatment takes place inductively, the damaged region S can be produced without the cable jacket 7 first having to be removed in the area to be processed. By offsetting the cut 9 and the damaged region S, it can be further achieved that any residue of the cable film 6 remaining on the inner conductor during stripping is concealed by the cable jacket 7, so that the insulated area of the inner conductor 4 is in any case free of plastic residue that inhibit contacting.

[0082] FIG. 1c shows the cable 1 during a stripping movement of the cable film 6, wherein a crack has already formed in the damaged region S, which has expanded or was enlarged by stripping, i.e. by the movement of the cable film 6 in the direction of the cable end 1a.

[0083] The present design example takes advantage of the fact that the cable film 6 usually adheres to the cable jacket 7 or that the bond between the cable jacket 7 and the cable film 6 is greater than between the cable film 6 and the conductor structure 3 located thereunder, here on the inner conductor 4. Accordingly, the section 7a of the cable jacket 7 to be removed and the section 6a of the cable film 6 to be removed are jointly removed by a common relative movement. This also allows for easier gripping of the cable film 6, since the cable jacket 7 can be gripped and moved by a corresponding stripping tool.

[0084] It should not be left unmentioned that the relative movement, which leads to the formation of the crack, does not (exclusively) necessarily have to be a translational movement, but can conceivably also be a rotary movement or a bending action. The removal of the sections 6a, 7a to be removed from the cable film 6 and cable jacket 7 after the crack formation is preferably done by means of a translational stripping movement in the direction of the cable end 1a.

[0085] After the removal of the sections 6a, 7a to be removed from the cable film 6 and cable jacket 7, a cable 1 remains in whose end area 1b the inner conductor 4 is exposed for contacting.

[0086] FIGS. 2a to 2c show the steps of the method according to the present teaching already discussed in connection with the first design example, which is why only the differences of the second design example are discussed in detail in comparison to the first design example.

[0087] While the cable 1 in the first design example comprises only a single conductor structure 3, namely the inner conductor 4, the cable 1 in the second design example comprises an inner conductor 4 and an outer conductor structure 5, namely a metal braiding 5a formed as a braided shield. The cable film 6 is not applied directly onto the inner conductor 4, but on the outer conductor structure 5, i.e. the metal braiding 5a. In order to prevent contacting between the metal braiding 5a and inner conductor 4, an inner insulation layer 8 is arranged between the inner conductor 4 and the metal braiding 5a.

[0088] Furthermore, it is discernible, in particular in FIG. 2b, that in the present design example, the section 7a of the cable jacket 7a to be removed was already removed before inserting the end section 1b into the induction coil 12. Although this is not necessarily required, as mentioned above, the inductive heating of the outer conductor structure 5 naturally also works if no section of the cable jacket 7 in the induction coil 12 is present between the conductor structure 3, 5, 5a to be heated and the induction coil 12. In the present design example, the penetration depth can be selected by means of the induction coil 12 by a corresponding selection of the induction parameters, such as amplitude and frequency of the induction current, such that the metal braiding 5a is heated in particular in the damaged region S, so that the cable film 6 located on the metal braiding 5a is thermally damaged in the damaged region S. In particular, it is advantageous if the insulating layer 8 has a higher thermal resistance than the cable film 6 in order to prevent the insulating layer 8 from being significantly thermally damaged in the damaged region S.

[0089] FIG. 2c shows that the section 6a of the cable film 6 to be removed is removed from the end section 1b by a relative movement of the cable film 6 to the metal braiding 5a.

[0090] FIGS. 3a to 3c show the previously described steps of the method according to the present teaching in connection with a particularly preferred third embodiment. Once again, only the differences from the previously described design examples are addressed below.

[0091] In this design example, the cable 1 has three conductor structures 3, namely one inner conductor 4 and two outer conductor structures 5. As in the second design example, the first outer conductor structure 5a is a metal braiding 5a designed as a braided shield that is applied onto an insulating layer 8. On the metal braiding 5a, there is a second outer conductor structure in the form of a metal film 5b. In the present design example, the cable film 6 is applied onto the metal film 5b, wherein it is also conceivable that the metal film 5b and cable film 6 are formed as a composite film. This cable structure is a typical cable structure of a coaxial cable, wherein the metal braiding 5a acts as the braided shield.

[0092] In FIG. 3a, it can be seen that the cable jacket 7 is completely intact when inserting the end section 1b into the induction coil 12, and a cut 9 is therefore also not provided.

[0093] FIG. 3b shows that the cut 9 can be produced before, after, or during the inductive heating of the metal film 5b by means of the induction coil 12, but in the same processing device 10 (see FIGS. 4 to 6). In the present design example, the penetration depth can be selected by means of the induction coil 12 by a corresponding selection of the induction parameters, such as amplitude and frequency of the induction current, such that the metal film 5b is heated in particular in the damaged region S, so that the cable film 6 located on the metal film 5b is thermally damaged in the damaged region S.

[0094] Subsequently, as can be seen in FIG. 3c, the metal braiding 5a is exposed by removing from cable film 6 and cable jacket 7 the sections 6a, 7a to be removed. When moving cable jacket 7 and cable film 6 relative to the inner conductor 4 or to the metal braiding 5a, a crack is formed also in the metal film 5b in the damaged region S, so that the metal film 5b can also be removed together with cable jacket 7 and cable film 6 from the section to be exposed of the end section 1b of cable 1.

[0095] The combined removal can be achieved particularly easily with a composite film, but it is also conceivable that the tensile strength of the metal film 5b is reduced by the thermal damage to the cable film 6 such that a crack is formed in the metal film 5b during the relative movement due to the high adhesion between the cable film 6 and the metal film 5b.

[0096] It goes without saying that the above-described design examples, in particular with regard to the cable structures and the positions of the cuts 9, can be easily combined with one another. Additional layers, both insulating layers 8 and conductor structures, can also be provided, wherein the above-described exposure of inner conductors 4 and/or metal braids 5a can be repeated in stages with the above-described steps.

[0097] The operating principles of the method according to the present teaching will now be illustrated based on the processing device 10 shown in FIGS. 4 to 7. The processing device 10 in this case delimits a processing space 11, the processing space 11 accommodating an end section 1b of a cable 1 to be processed and having at least one insertion opening 16 for inserting the end section 1b. The structure of the cable 1 corresponds to the structure described in the context of FIGS. 3a to 3c, so that, the cable 1 comprises in the following order an inner conductor 4, an insulating layer 8, a metal braiding 5a designed as a braided shield, and a metal film 5b, a plastic film 6 applied on the metal film 5b, and a cable jacket 7.

[0098] The induction coil 12 is arranged in the processing space 11, wherein the end section 1b is guided through the induction coil 12, so that at least that section of cable 1 in which the damaged region S is to be generated is arranged inside the induction coil 12.

[0099] Furthermore, in order to fix the end section 1b of the cable 1, at least one clamping unit 15 is provided in the processing space 11 by means of which the end section 1b can be clamped during processing. The clamping unit 15 preferably comprises one or more clamping elements made of plastic, so that they can be positioned in the immediate proximity of the induction coil 12.

[0100] Furthermore, the processing device 10 comprises a cutting unit 14 with at least one cutting element 14a for producing a cut 9 in the cable jacket 7 and means 13 for stripping (a “stripper”) the section 6a of the cable film 6 to be removed. In the present design example, the means 13 for stripping comprise a grip element 13a that is designed to grip the cable jacket 7 or the cable film 6, as well as a motion device 13b by which the grip elements 13a can be moved relative to the cable 1, preferably shifted or twisted, as soon as they have circumferentially gripped the cable jacket 7 or the cable film 6.

[0101] FIG. 4 shows the first step of the method, namely the provision of an end section 1b of a cable 1, which has at least one conductor structure 3 and in which a plastic cable film 6 is applied onto one of the conductor structures 3. In the shown state of the processing device 10, the clamping unit 15 is already in a state of clamping the remaining section 7b of the cable jacket 7 and the grip elements 13a are engaged with the section 7a of the cable jacket 7 to be removed. The induction coil 12 is arranged in relation to the cable axis 2 between the means 13 for stripping the cable film 6 and the clamping unit 15 in order to fix the section of the cable 1 to be processed.

[0102] FIG. 5 now shows the step of generating the defined damaged region S by inductively heating the conductor structure 3, in the present case the metal film 5b, which is in contact with the cable film 6, by means of the induction coil 12 such that the cable film 6 is thermally damaged in the damaged region S. In order to achieve such a defined damage, the geometry of the preferably water-cooled induction coil 12 as well as the induction parameters, such as amplitude and frequency as well as heating duration, are selected such that an electromagnetic alternating field is generated in the induction coil 12, wherein a maximum heating of the metal film 5b is achieved by means of the penetration depth represented by the alternating field. Since the metal film 5b withstands a significantly higher thermal load due to the material properties than the plastic cable film 6 applied thereon, the cable film 6 is thermally damaged in the damaged region S by the inductive heating of the metal film 5b, for example melted or embrittled or degraded. In order to achieve such thermal damage, cable film 6 is brought to a temperature between 120° C. and 200° C. in the damaged region S by means of the inductively heated metal film 5b. The duration of the inductive heating is advantageously less than 20 s, preferably less than 10 s.

[0103] It is also conceivable in alternative design examples that the metal film 5b is designed to be structurally weakened by the inductive heating, so that a defined crack formation of the metal film 5b is achieved in the damaged region S.

[0104] Due to the inductive heating, the cable jacket 7 can be completely intact during the heating process, since the electromagnetic alternating field can penetrate the cable jacket 7 without this leading to heating or the penetration being impeded by the cable jacket 7. End sections 1b of cables 1 with different diameters and cable structure can also be processed by means of an induction coil 12, since only the parameters of the electromagnetic alternating field must be set accordingly.

[0105] In FIG. 6, the end section 1b is shown after a cut 9 is produced in the cable jacket 7 by means of the cutting unit 14. Here, the cutting elements 14a penetrate into the cable jacket 7 in the radial direction, wherein the cutting elements 14a are designed to produce an at least partially, preferably completely circumferential cut 9. When the cutting unit 14 is movably held in the processing device 10, as shown, the section 7a of the cable jacket 7 to be removed can be shifted by means of the cutting unit 14 in the direction of the cable end 1a in order to enlarge the cut 9 in the axial direction.

[0106] The cutting unit 14 is arranged between the means 13 for stripping the cable film 6, in particular between the grip elements 13a, and the induction coil 12, so that the section between the cut 9 and the cable end 1a is smaller than the distance between the cable end 1a and the induction coil 12. From the vantage point of the insertion opening 16, the induction coil 12 is positioned between the insertion opening 16 and the cutting unit 14. A corresponding positioning of the cutting unit 14 ensures that any residue of the cable film 6 remaining during subsequent relative movement and stripping are concealed in the damaged region S by the remaining section 7b of the cable jacket 7 and thus do not negatively affect a contacting of the metal braiding 5a.

[0107] In alternative design variants of the method in which the cut 9 is made prior to the inductive heating, the described positioning of the cutting unit 14 ensures that the cable jacket 7 is intact in the region of cable 1 in which the damaged region S is generated by means of the induction coil 12.

[0108] As already mentioned in connection with the design examples shown in FIGS. 1a to 3c, the cutting unit 14 is not necessarily a required part of the processing device 10 because the cut 9 can also be produced before the end section 1b is inserted into the processing space 11 or the cable jacket 7 can be removed in the section to be processed prior to insertion.

[0109] FIG. 7 shows the step of moving the cable film 6 relative to the conductor structures 3 remaining on cable 1, namely relative to the inner conductor 4 and to the metal braiding 5a. The relative movement, which can be a translational movement, a twisting movement, or a bending movement forms a crack in the damaged region S in the cable film 6, which separates the section 6a and the remaining section 6b of the cable film 6 from each other. Furthermore, a crack in the metal film 5b is also formed in the damaged region S, so that the metal film 5b can subsequently also be removed together with the sections 6a, 7a of cable film 6 and cable jacket 7 in order to expose the metal braiding 5a for contacting.

[0110] In the present design example, the movement of the grip elements 13a, which clamp the section 7a of the cable jacket 7 to be removed, also causes the section 6a of the cable film 6 adhering to the cable jacket 7, as well as the metal film 5b attached to the cable film 6, in particular when cable film 6 and metal film 5b are formed as a composite film, to be moved relative to the metal braiding 5a in order to form the crack. The crack will usually be formed based on the thermal damage to the cable film 6.

[0111] As soon as the crack in the damaged region S is formed in the metal film 5b and cable film 6, the removing sections 6a, 7a from cable film 6 and cable jacket 7, as well as from the metal film 5b, can be readily removed completely from cable 1, preferably by means of means 13 for stripping, in order to expose the metal braiding 5a formed as a braided shield.

[0112] It should not be left unmentioned that the above-described processing device 10 can accordingly also process cables with cable structures as shown in the above-detailed design examples, as well as cables with cable structures that have one or more intermediate layers.

[0113] Even if all relevant elements of the processing device 10 are for easier comprehension shown in FIGS. 4 to 7 arranged in a common processing space 11, which additionally causes a particularly short total duration for the removal of the section 6a of the cable film 6 to be removed, alternative design variants of the present teaching, in particular when the processing device 10 is designed as a system with several sub-devices, can provide that the cutting unit 14 and/or the means 13 for stripping the cable film 6 are each arranged in separate further processing spaces. For example, the cutting unit 14 can be arranged in a further processing space of a cutting device of the processing device 10 and/or the means 13 for stripping the cable film 6 can be arranged in a further processing space of a jacket stripping device of the processing device 10, while the induction coil 12 and preferably the damping unit 15 are arranged in the processing space 11.