Method for producing a strand or cable

Abstract

A method for producing a strand or cable, in which fibers and/or wires are twisted at a twisting point to form the strand or cable. The fibers and/or wires are coated with a liquefied matrix material before and/or at the twisting point and are embedded in the matrix material during twisting. The fibers and/or wires are immersed in the matrix material before and/or at the twisting point and the formed strand or the formed cable is cooled after the twisting in order for the matrix material to solidify, preferably by air or in a cooling liquid, for example water.

Claims

1. A method for producing a strand, comprising the steps of: coating fibers and/or a monofilament bundle of fibers with a liquefied matrix material, that solidifies after stranding, before and/or at a stranding point; stranding the fibers and/or monofilament bundle of fibers at the stranding point to form a core strand, the fibers and/or the monofilament bundle of fibers embedding in the matrix material during stranding; applying a jacketing made of the matrix material on the core strand; and, after stranding the core strand, a) stranding a layer of steel wire on the jacketed core strand whereby the steel wire is embedded in the matrix material, and/or b) applying an additional jacketing on the jacketed core strand and embedding the additional jacketing on the matrix material.

2. The method according to claim 1, wherein the coating step includes immersing the fibers and/or the monofilament bundle of fibers in the matrix material or spraying the fibers and/or the monofilament bundle of fibers with the matrix material before and/or at the stranding point.

3. The method according to claim 1, further including cooling the strand after the stranding to solidify the matrix material.

4. The method according to claim 3, including stretching the fibers during the stranding, the embedding in the matrix material, and the cooling of the matrix material, until the matrix material has solidified, so that the fibers are held by the matrix material in a position which they assume in the stretched state.

5. The method according to claim 4, including stretching the fibers until the fibers reach a position which they assume when absorbing load.

6. A cable, comprising: a core cable containing monofilament bundles of fibers, wherein the fibers are natural fibers, mineral fibers, glass fibers, carbon fibers and/or synthetic fibers and the monofilament bundles are coated with and embedded in a matrix material so that each of the monofilament bundles is surrounded by the matrix material, wherein the matrix material forms a jacketing on the monofilament bundle of fibers; and a layer of strands cabled onto and embedded in the jacketing.

7. The cable according to claim 6, wherein the fibers consist of high-strength plastic and/or the matrix material comprises a thermoplastic.

8. The cable according to claim 6, wherein the fibers in the core cable are stretched to such an extent that they are in a position which they have when absorbing load.

9. The cable according to claim 6, wherein the fibers in the core cable are stretched to such an extent that, when the cable is absorbing a load, the fibers directly undergo plastic stretching according to Hooke's law.

10. The cable according to claim 6, further comprising a jacketing, which surrounds the core cable and holds the core cable together under tension.

11. The cable according to claim 10, wherein the jacketing is formed by a layer of braid.

12. The cable according to claim 11, wherein the braid comprises mesh openings that are permeated by the matrix material.

13. An apparatus for producing a strand or a cable, comprising: a device for supplying fibers and/or wires to a cabling point and for forming the fibers and/or the wires into a cable at the cabling point; a device for coating the fibers and/or the wires before and/or at the cabling point with a liquefied matrix material into which the fibers and/or the wires are embedded; and a device for applying a jacketing to the strand or cable, wherein the jacketing device is a braiding machine.

14. A method for producing a cable, comprising the steps of coating fibers and/or a monofilament bundle of fibers with a liquefied matrix material, that solidifies after cabling, before and/or at a cabling point; cabling the fibers and/or monofilament bundle of fibers at the cabling point to form a core cable, the fibers and/or the monofilament bundle of fibers embedding in the matrix material during cabling; applying a jacketing made of the matrix material on the core cable; and, after cabling the core strand, a) applying a layer of strands on the jacketed core cable whereby the strands are embedded in the matrix material, and/or b) applying an additional jacketing on the jacketed core cable and embedding the additional jacketing on the matrix material.

15. The method according to claim 14, further including applying a jacketing to the cable after the cabling step.

16. The method according to claim 14, wherein the coating step includes immersing the fibers and/or the monofilament bundle of fibers in the matrix material or spraying the fibers and/or the monofilament bundle of fibers with the matrix material before and/or at the cabling point.

17. The method according to claim 14, further including cooling the cable after the cabling to solidify the matrix material.

18. The method according to claim 17, including stretching the fibers during the cabling, the embedding in the matrix material, and the cooling of the matrix material, until the matrix material has solidified, so that the fibers are held by the matrix material in a position which they assume in the stretched state.

19. The method according to claim 18, including stretching the fibers until the fibers reach a position which they assume when absorbing load.

20. A strand, comprising: a core strand containing monofilament bundles of fibers, wherein the fibers are natural fibers, mineral fibers, glass fibers, carbon fibers and/or synthetic fibers and the monofilament bundles are coated with and embedded in a matrix material so that each of the monofilament bundles is surrounded by the matrix material, wherein the matrix material forms a jacketing on the monofilament bundle of fibers; and a layer of steel wires stranded onto and embedded in the jacketing.

21. A cable, comprising: a core cable containing fibers and/or monofilament bundles of fibers, wherein the fibers and/or the monofilament bundles are coated with and embedded in a matrix material and the matrix material forms a jacketing on the fibers and/or the monofilament bundle of fibers; a) a layer of strands cabled onto and embedded in the jacketing, and/or b) an additional jacketing provided on and embedded in the jacketing; and a jacketing, which is formed by a layer of braid and surrounds the core cable and holds the core cable together under tension.

22. The cable according to claim 21, wherein the braid comprises mesh openings that are permeated by the matrix material.

Description

(1) The invention is explained in greater detail below on the basis of exemplary embodiments and the attached drawings, which relate to the exemplary embodiments:

BRIEF DESCRIPTION OF THE DRAWING

(2) FIG. 1 shows a schematic diagram of an inventive device;

(3) FIG. 2 shows a detail of the inventive device in the form of an isometric diagram;

(4) FIG. 3 shows a detail of another inventive device in the form of an isometric diagram;

(5) FIG. 4 shows a schematic diagram of another inventive device;

(6) FIG. 5 shows a detail of the inventive device according to FIG. 4 in the form of an isometric diagram;

(7) FIG. 6 shows a cross section of an inventive cable;

(8) FIG. 7 shows a cross section of another inventive cable;

(9) FIG. 8a shows a cross-section of an inventive strand;

(10) FIG. 8b shows the strand of FIG. 8a after compacting;

(11) FIG. 9 shows a cross section of another inventive cable;

(12) FIG. 10 shows a cross section of another inventive cable;

(13) FIG. 11 shows a cross section of another inventive cable;

(14) FIG. 12 shows a cross section of another inventive cable; and

(15) FIG. 13 shows a cross section of another inventive cable.

DETAILED DESCRIPTION OF THE INVENTION

(16) An inventive device shown in FIG. 1 for the production of cables or strands comprises a rotor 9, over which twisted monofilament bundles 2 or aramid fibers are guided to a cabling point 3. On the rotor 9, spools of the type known in themselves (not shown) are arranged, on which the monofilament bundles are wound. During the cable-forming process, the monofilament bundles 2 are unwound continuously from the spools as the rotor 9 turns in the direction of the arrow P. At the cabling point 3, the monofilament bundles 2 are formed into a cable 20 in the manner known in itself. By means of rollers 15, the cable 20 is pulled from the cabling point 3 and wound up on a cable drum.

(17) At the cabling point 3, a container 7, which is shown in more detail in FIG. 2, surrounds the monofilament bundles 2 and the cable 20. The container 7 has a conical shape and is provided at the end facing the rotor 9 with a rotatable end wall 10, which has several openings 11 and which is rigidly connected to the rotor 9 by a connecting web 16. The twisted monofilament bundles 2 are guided from the rotor 9 through the openings 11 to the cable-forming point 3. Only four monofilament bundles 2 are shown in FIG. 2 to serve as an example. Depending on the application, various numbers of openings 11 suitable for the number of monofilament bundles 2 to be formed into a cable can be provided.

(18) The device can form cables not only out of twisted monofilament bundles 2 but also out of previously formed strands. The monofilament bundles 2 can also be formed into cables in combination with previously formed strands.

(19) Another opening 12, through which the cable 20 is guided out of the container 7, is provided at the end of the container 7 opposite the end wall 10. The opening 12 has a diameter which corresponds to the diameter of the cable 20 to be formed. Instead of a circular shape for the opening 12, it is also possible to use some other shape, preferably an asymmetric, angled-oval, or polygonal (e.g., three-sided, four-sided, or five-sided) shape or the shape of a section of a circle (e.g., a semi-circle or quarter-circle).

(20) The container 7 is connected by a heated pipe 13 to an extruder 8, by means of which polypropylene is continuously liquefied and supplied to the container 7. So that the polypropylene 4 remains liquid in the container 7, the container 7 is provided with heating tapes (not shown) in its lateral surface so that it can be heated to a temperature of 200-300 C. A temperature sensor is provided in the container to monitor the temperature.

(21) To produce the inventive cable 20, the monofilament bundles 2 are drawn continuously to the cabling point 3. When the rotor 9 turns, the end wall 10 is turned along as well by the connecting web 16 at the same rotational speed, so that the monofilament bundles 2 are guided continuously through the openings 11 to the cabling point 3. The seals (not shown) provided on the openings 11 prevent polypropylene 4 supplied through the connecting pipe 13 from escaping from the container 7.

(22) In the container 7, the monofilament bundles 2 are coated with the polypropylene 4 before they reach the cabling point 3. The cable-forming process at the cabling point 3 also takes place completely in the polypropylene 4. During the cabling process, the polypropylene 4 is supplied continuously to the container by the extruder 8.

(23) The formed cable is guided out of the container 7 through the opening 12 and into a water bath 14, in which the polypropylene 4 is cooled and solidified. By means of a tensioning device (not shown) to stretch the cable, the cable can be prestretched in such a way that the monofilament bundles 2 assume the position in the cable which they assume under the load which the cable is intended to absorb during use. The monofilament bundles 2 are held by the polypropylene 4 in the stretched state. They are frozen in this stretched condition.

(24) FIG. 6 shows a cable 20 of aramid fibers produced by means of the method described above. Several fiber strands 21, 22, wound from several twisted monofilament bundles, have been formed into the cable 20. The monofilament bundles, shown as black dots, are surrounded by the polypropylene 4.

(25) Reference is made in the following to FIGS. 3-5 and 7-12, where the same parts or parts of similar function are designated by the same reference numbers as those used in FIGS. 1, 2, and 6, a letter being appended to each of the associated reference numbers.

(26) An inventive device shown in FIG. 3 differs from those according to FIGS. 1 and 2 in that a connecting web 16a, which is connected to the rotor, is hollow on the inside, and in that a core cable 23 is guided through the connecting web 16a to the cabling point 3a. At the cabling point 3a, the core cable 23 is formed into a cable 20a with the external strands 24 and coated with polypropylene 4a as described above.

(27) As an option, the device can also comprise a braiding device 35, indicated only schematically here, by means of which a layer of braid 27 can be applied to the core cable 23 and embedded in the polypropylene 4a. The surrounding layer of braid forms a braided cable 20a out of the cable 20a.

(28) Another inventive device, shown in FIGS. 4 and 5, comprises, in its container 7b, a calibration ring 30, formed by a ring mounted in the container 7b, through which a core cable 22b to be formed, is pulled to give it its shape after fibers 2b have been wound around the core cable 22b. At one end of the container 7b, namely, the end from which the core cable 22b leaves the container 7b, a section of pipe 31 is arranged. The inside diameter of the pipe section 31, in the walls of which a water cooling circuit is provided, is larger than the opening of the calibration ring 30. Polypropylene 4b, with which the fibers 2b are coated, is cooled in the pipe section 31 to a viscosity such that, upon emergence from the pipe section 31, it retains its shape but still remains soft.

(29) The device according to FIG. 5 can be used to provide the core cable 22b with a jacketing 26 of polypropylene 4b on the fibers.

(30) FIG. 7 shows a composite cable 20a, which comprises a core cable 22a, which corresponds to the cable 20 described above. The core cable 22a is surrounded by a jacketing 26 of the polypropylene 4a forming the matrix material. Steel strands 24 have been wound around the core cable 22a and thus embedded in the jacket 26. The steel strands were pressed into the matrix material 4a of the jacket 26 while the material was still soft.

(31) FIG. 4 shows a schematic diagram of optional enhancements to the part of the device shown in FIG. 5. Downstream in the cable-forming direction from the pipe section 31, a braiding device 26b can be provided, by means of which a layer of braid can be applied to the core cable 22b.

(32) In addition, another cabling device 36 can be provided, by means of which external strands 24b can be wound onto the core cable 22b, the strands 24b thus becoming embedded in the matrix material 4b.

(33) FIG. 8a shows a strand 1, the core strand 22b of which has been produced by the inventive method and consists of aramid fiber strands embedded in polypropylene. Steel wire 24b, shown only schematically here, has been pressed directly into the core cable 22b as the core cable 22b was being heated during the cable-forming process. FIG. 8b shows a strand 1, which is constructed like that according to FIG. 8a but which has been compacted by hammering, for example.

(34) A composite cable 20c shown in FIG. 9 comprises a core cable consisting of three twisted, polypropylene-embedded fiber strands 21c of monofilament bundles of aramid fibers, into which, during the cabling process, external strands 1c have been pressed. The external strands 1, only one of which is shown in detail, comprise, as a core, polypropylene-embedded aramid fibers 23. In the polypropylene 4c, steel wire strands 24c are arranged around the aramid fibers 23.

(35) FIG. 10 shows a composite cable 20d, which comprises a core cable embedded in polypropylene 4d. The core cable comprises a core 21d of polypropylene-embedded monofilament bundles 21d of aramid fibers, in which steel wire strands 24c are embedded, and around which an additional layer of steel wire strands 25 is wound. External strands 1d are seated in the polypropylene 4d; these have the same structure as that described above for the strands 24c of the exemplary embodiment according to FIG. 9.

(36) An inventive composite cable 20e shown in FIG. 11 differs from the cables of the previous exemplary embodiments in that the external strands 1e are completely embedded in a matrix material of polypropylene 4e. A core cable of the cable 20e comprises a core strand 32 of steel wire and strands 24e, 25e wound around it, which comprise here a core (not shown) of aramid fibers embedded in polypropylene. The core strand 32 and the strands 24e, 25e are surrounded by a lubricant 33. Around the lubricant 33 and the core cable, the method described above is used to cable the external strands 1e onto the core cable, and as this is done the core cable with the lubricant 33 is completely embedded together with the external strands 1e in the polypropylene 4e.

(37) A cable shown in cross section in FIG. 12 can be produced by using the previously mentioned braiding device 31 to apply a layer of braid 27 into the jacketing 26 around the fibers 22f of a core cable. The layer of braid 27 is also embedded in the matrix material 4f surrounding the fibers 22f, and a good bond is achieved between the fibers on the one side and the braid 27 on the other. A jacket 26 of matrix material 4f is formed around the braiding 27. As shown in FIG. 13, external strands 24g can be embedded in this jacket 26.

(38) It is obvious that the examples described here can be carried out with matrix materials other than the polypropylene mentioned. For example, polycarbonate, polyamide, polyethylene, or PEEK could be used instead.

(39) In should also be obvious that the individual steps of the method described here can be combined with each other in any way desired depending on the cable structure to be produced. In corresponding fashion, individual components of the production device such as the container, the device for winding the external strands onto the cable, and the braiding device, possibly even several devices of the same type, can also be combined with each other in accordance with the method to be applied.