METHOD AND DEVICE FOR CLEANING THE SURFACE OF A METAL WIRE OR METAL STRIP

Description

Technical field

[0001] The invention relates to a method for cleaning the surface of a metal wire or metal strip, a device for cleaning the surface of a metal wire or metal strip, and a use of the device according to the preambles of the independent claims. State of the art

[0002] In resistance roll seam welding machines for tinplate packaging, such as food cans, a copper wire serves as an intermediate electrode to keep the electrode rolls clean by absorbing and carrying away the tin released from the tinplate during welding. To ensure good electrical contact between the wire and the electrode roll, it is essential that the wire is free of dust and other contaminants. For cost reasons, the wire is used twice in such resistance roll seam welding machines: once for the first electrode roll and again for the second.

[0003] Since the wire already contains certain impurities, such as copper oxide, when delivered, and copper dust is generated during flat profiling for use as an intermediate electrode, it is advisable to clean the wire before its first use, and in any case before its second use. This is particularly important for highly tinned tinplate (5 to 12 g / m²), as required for certain vegetable and fruit cans.

[0004] According to current technology, the wire is drawn between two brushed discs for cleaning. These discs have an unsatisfactory and inconsistent cleaning effect and wear out quickly. They also require regular cleaning to remove the copper dust that accumulates on them. Furthermore, cooling the wire, which would be desirable after flat profiling or initial use, is hardly possible with these brushed discs.

[0005] Document DE 10 2012 017 171 A1, which forms the basis for the preamble of the independent claims, discloses a wire cleaning device in which the wire is guided through a housing in which, viewed in the direction of wire travel, cleaning brushes act on the wire successively at various circumferential positions. In practice, this gives rise to similar problems as previously described.

[0006] From CH 691 668 A5, a device for cleaning strip-shaped copper wire is known, in which the wire is guided over a guide roller with a guide groove, and the outer surface of the wire is in contact with the cutting edge of a rotating knife disc. This device has the disadvantage that there is only point contact between the wire surface and the cutting edge of the knife disc, which makes thorough cleaning impossible from the outset. Another disadvantage is that the material stripped from the wire enters the surrounding area uncontrollably. A further disadvantage of this device is that placing the wire on the guide roller is only possible after removing or pivoting the knife disc away. Description of the invention

[0007] The task therefore arises to provide technical solutions that at least partially avoid the disadvantages of the state of the art.

[0008] This problem is solved by the subject matter of the independent patent claims.

[0009] According to these, a first aspect of the invention relates to a method for cleaning the surface of a metal wire or metal strip. Preferably, this is a method for cleaning the surface of a metal wire or metal strip used as an intermediate electrode in a roll seam welding machine.

[0010] According to the invention, the metal wire or metal strip is guided under tension in the longitudinal direction of the wire or strip along several stripping bodies arranged one behind the other in the longitudinal direction of the wire or strip at a distance from each other, such that the wire or strip sections lying between two successive stripping bodies together form an arc-shaped wire section, in particular with the shape of an arc-shaped polygon.

[0011] It has been shown that this enables intensive and reliable cleaning with consistent cleaning quality.

[0012] Preferably, the scraper elements are provided in a freely accessible position on the outside of a common carrier body, such that the metal wire or metal strip can be placed onto the scraper elements by hand, and preferably also in such a way that no tools are required for this, nor do any components need to be moved or disassembled. This enables simple and straightforward handling during maintenance work.

[0013] In a preferred embodiment of the previously described method, a carrier body is used which has an interior space in which the gaps between the scraper elements form passages through which the interior space is connected to the environment of the carrier body. While the metal wire or metal strip is guided along the scraper elements for cleaning its surface, the interior space is pressurized in this embodiment, causing the contaminants scraped off the scraper elements to be drawn out through the interior of the carrier body. This embodiment thus makes it possible to remove the material scraped from the wire in a controlled manner. The wire is also cooled by the vacuumed airflow passing over it.

[0014] It is advantageous that the openings, viewed in the longitudinal direction of the wire or strip, have a width at least twice the width of the metal wire or strip. This ensures that sufficiently large inlet openings are formed between the wire and the edges of the openings to generate an airflow suitable for carrying away the material stripped from the wire.

[0015] In a further preferred embodiment of the method, guide elements are arranged in the longitudinal direction of the wire or strip before and after the stripping bodies which are arranged at a distance from one another, preferably guide pins, by means of which the metal wire or metal strip is guided transversely to its bearing direction on the stripping bodies in such a way that the metal wire or metal strip is guided over the stripping bodies without running into the sides.

[0016] In process variants where a support body carrying the scraper elements is used, it is preferred that the guide elements are provided in the support body. This allows them to be easily positioned in the immediate vicinity of the scraper elements.

[0017] In yet another preferred embodiment of the inventive method, the scraper elements used are designed and the metal wire or strip is guided past the scraper elements in such a way that the metal wire or strip first passes a scraper edge at each scraper element to remove contaminants from its surface, and is then guided along a contact surface of the scraper element to cool the metal wire or strip. This allows the wire to not only be cleaned while passing the scraper elements, but also to be actively cooled by them.

[0018] The process advantageously utilizes ceramic or carbide scrapers. Such scrapers can be procured cost-effectively, for example in the form of cutting inserts for machining metal, and offer a long service life.

[0019] The metal wire or metal strip which is cleaned according to the inventive method preferably consists of copper or a copper alloy.

[0020] In yet another preferred embodiment of the method, in a first step a substantially round metal wire is flattened so that, in cross-section, it has two parallel flat sides. Immediately after flattening, in a second step, the wire is first guided with one of the two flat sides under tension in the longitudinal direction of the wire or strip along several first stripping bodies arranged one behind the other in the longitudinal direction of the wire or strip, such that the wire or strip sections lying between each pair of successive first stripping bodies together form an arc-shaped wire section, in particular with the shape of an arc-shaped polygon. Immediately thereafter, the wire is guided with the other of the two flat sides under tension in the longitudinal direction of the wire or strip along several second stripping bodies arranged one behind the other in the longitudinal direction of the wire or strip.The strip is guided along the longitudinal direction with stripping bodies arranged one behind the other at a distance, such that the wire or strip sections lying between two successive second stripping bodies together form an arc-shaped wire section, in particular with the shape of an arc-shaped polygon.

[0021] This method is particularly well suited for the preparation and cleaning of a copper wire intended for use as an intermediate electrode for roll seam welding machines.

[0022] A second aspect of the invention relates to a device for cleaning the surface of a metal wire or metal strip, preferably a metal wire or metal strip used or to be used as an intermediate electrode of a roll seam welding machine, wherein the cleaning can preferably be carried out according to the method according to the first aspect of the invention.

[0023] The device comprises a carrier body with several scraper bodies arranged at a distance from one another such that a metal wire or a metal strip to be cleaned can be guided along the scraper bodies under tension in the longitudinal direction of the wire or strip, and the wire or strip sections lying between two successive scraper bodies together form an arc-shaped wire section, in particular with the shape of an arc-shaped polygon.

[0024] It has been shown that such a device enables intensive and reliable cleaning with consistent cleaning quality.

[0025] Preferably, the wiper elements are freely accessible on the outside of the common carrier body, such that the metal wire or metal strip can be placed onto the wiper elements by hand, and preferably also such that no tools are required or components need to be moved or disassembled. This enables simple and straightforward handling during maintenance work.

[0026] In a preferred embodiment of the device described above, the carrier body has an interior space, and the spaces between the scraper elements form passages through which the interior space is connected to the environment of the carrier body. While the metal wire or strip is being guided along the scraper elements for cleaning its surface, the interior space can be pressurized, allowing the contaminants scraped off the scraper elements to be drawn out through the interior of the carrier body. This embodiment thus makes it possible to remove the material scraped from the wire in a controlled manner. The wire can also be cooled by the suction airflow passing over it.

[0027] In a further preferred embodiment of the device, guide elements, preferably guide pins, are arranged upstream and downstream of the stripping bodies, which are spaced apart, in the longitudinal direction of the wire or strip. These guide elements allow the metal wire or strip to be guided transversely to its bearing direction on the stripping bodies, in particular such that the metal wire or strip is guided substantially centrally over the stripping bodies. This ensures that the wire contacts the stripping bodies at the designated points and, in the aforementioned embodiment of the device, also creates inlet openings of substantially equal width on both sides of the wire to generate an airflow suitable for carrying away the material stripped from the wire and cooling the wire.

[0028] It is preferred that the guide elements are provided in the carrier body. This allows them to be easily arranged in close proximity to the scraper elements.

[0029] In yet another preferred embodiment of the device, the scraper elements are designed and the metal wire or strip can be guided past the scraper elements in such a way that the metal wire or strip first passes a scraper edge at each scraper element to remove contaminants from its surface, and is then guided along a contact surface of the scraper element to cool the metal wire or strip. This allows the wire to not only be cleaned while passing the scraper elements, but also to be actively cooled by them.

[0030] The scraper elements of the device according to the invention are preferably made of hard metal or ceramic. Such scraper elements can be obtained cost-effectively, e.g., in the form of cutting inserts for machining metal, and have a long service life.

[0031] A third aspect of the invention relates to the use of the device according to the second aspect of the invention for cleaning a metal wire or a metal strip made of copper or a copper alloy. The advantages of the invention become particularly evident in such uses. Brief description of the drawings

[0032] Further advantages and applications of the invention will become apparent from the following description with reference to the figures. These show: Fig. 1 a perspective view of a device according to the invention for cleaning the surface of a copper wire; Fig. 2 a longitudinal section through the device Fig. 1; Fig. 3 detail X from Fig. 2 ; and Fig. 4 a schematic representation of a method according to the invention using the device made of Fig. 1 . Ways to implement the invention

[0033] Fig. 1 Figure 1 shows a perspective view of a device 1 according to the invention for cleaning the surface of a copper metal wire 2 used as an intermediate electrode of a roll seam welding machine. Fig. 2 shows a longitudinal section through the device made of Fig. 1

[0034] As can be seen from a synthesis of the Figures 1 and 2As can be seen, the device 1 comprises a carrier body 3 made of aluminum or brass with several scraper elements 4 made of hard metal, which are arranged one behind the other at a distance such that the copper wire 2 to be cleaned can be guided along the scraper elements 4 under tension in the longitudinal direction of the wire and the wire or strip sections 5a-5g lying between two successive scraper elements (for the sake of clarity only in Fig. 1 (with reference numbers) together forming an arc-shaped wire section which has the shape of an arc-shaped polygon.

[0035] The scraper bodies 4 are freely accessible on an outside of the carrier body 3, so that the copper wire 2 to be cleaned can be placed on the scraper bodies 4 by hand and without the use of tools.

[0036] The carrier body 3 has an interior space 6, and the spaces between the wiper elements 4 form passages 7 through which the interior space 6 is connected to the environment of the carrier body 3. These passages 7 have a width, viewed in the longitudinal direction of the wire 2, that is at least twice the width of the wire 2. During the process of guiding the copper wire 2 along the wiper elements 4, the interior space 6 of the carrier body 3 can be pressurized with a vacuum to clean the surface of the wire 2 and to draw off the contaminants wiped from the wiper elements 4 through the interior space 6 of the carrier body 3.

[0037] As can be further seen, guide pins 8 are arranged in the carrier body 3 in the longitudinal direction of the wire before and after the stripping bodies 4 which are arranged at a distance from one another, by means of which the copper wire 2 is guided transversely to its bearing direction on the stripping bodies 4 in such a way that it runs over the stripping bodies 4 without running over them laterally.

[0038] As seen in conjunction with Fig. 3 It is evident which detail X is from Fig. 2As shown, the wiper bodies 4 are designed and the copper wire 2 is guided past the wiper bodies 4 in such a way that the wire 2 first passes a wiper edge 9 at each wiper body 4 to remove impurities from its surface, and is then guided along a contact surface 10 of the wiper body 4 to actively cool the wire 2 with the respective wiper body 4. It should be noted that the deflection of the wire 2 by the wiper body 4 is exaggerated here for the purpose of illustrating the described situation.

[0039] Fig. 4 shows a schematic representation of a method according to the invention using the device made of Fig. 1, wherein a copper wire 2a, contaminated by its use as an intermediate electrode in the first electrode roll of a roll seam welding machine, is cleaned and fed as a cleaned copper wire 2b for reuse as an intermediate electrode in the second electrode roll of the roll seam welding machine.

[0040] In this process, the contaminated copper wire 2a is subjected to tensile stress in the longitudinal direction of the device 1 against the stripping bodies 4 of the device, which are arranged one behind the other in the longitudinal direction of the wire at a distance from each other. Fig. 1 is guided along, so that the wire sections 5a-5g lying between each of two successive stripping bodies 4 (see also Fig. 1 ) together form an arc-shaped wire section that has the shape of an arc-shaped polygon.

[0041] The impurities 14 removed in this process are extracted by means of a vacuum pump 12 via the interior 6 of the carrier body 3 and separated in a cyclone 11 before the extracted air is released back into the environment via a filter 13.

[0042] While preferred embodiments of the invention are described in the present application, it should be clearly pointed out that the invention is not limited to these and can also be carried out in other ways within the scope of the following claims.

Claims

1. A method for cleaning the surface of a metal wire (2) or a metal strip, in particular of a metal wire (2) or a metal strip used as an intermediate electrode of a roll seam welding machine, wherein the metal wire (2) or the metal strip is guided under tensile stress in the longitudinal direction of the wire or the strip along a plurality of wiping bodies (4) arranged at a distance one behind the other in the longitudinal direction of the wire or the strip, in such a way that the wire or the strip sections (5a, 5b, 5c, 5d, 5d) each lying between two successive wiping bodies (4) together form a bow-shaped wire section.

2. The method according to claim 1, wherein the bow-shaped wire section formed by the wire or the strip sections (5a-5g) each lying between two successive wiping bodies (4) is in the form of a bow-shaped polygonal line.

3. The method according to one of the preceding claims, wherein the wiping bodies (4) are provided freely accessible on an outer side of a common carrier body (3) in such a way that the metal wire (2) or the metal strip can be placed on the wiping bodies (4), in particular without tools.

4. The method according to claim 3, wherein the carrier body (3) has an interior space (6) and wherein the distances between the wiping bodies (4) form passages (7) via which the interior space (6) is connected to the surroundings of the carrier body (3), and wherein, while the metal wire (2) or the metal strip is guided along the wiping bodies (4) for the purpose of cleaning the surface of the metal wire (2) or the metal strip, the interior space (6) is pressurized with negative pressure for the purpose of extracting the contaminants stripped off at the wiping bodies (4) via the interior space (6) of the carrier body (3).

5. The method according to claim 4, wherein the passages (7), as viewed in the longitudinal direction of the wire or the strip, have a width which corresponds to at least twice the width of the metal wire (2) or the metal strip.

6. The method according to one of the preceding claims, wherein, as viewed in the longitudinal direction of the wire or the strip, guide elements (8), in particular guide pins (8), are arranged before and after the wiping bodies (4) arranged at a distance one behind the other, by means of which the metal wire (2) or the metal strip is guided transversely to its bearing direction on the wiping bodies (4) in such a way that the metal wire (2) or the metal strip is guided over the wiping bodies (4) without running up in a lateral direction.

7. The method according to one of the claims 3 to 5 and according to claim 6, wherein the guide elements (8) are provided in the carrier body (3).

8. The method according to one of the preceding claims, wherein the wiping bodies (4) are formed in such a way and wherein the metal wire (2) or the metal strip is guided along the wiping bodies (4) in such a way that the metal wire (2) or the metal strip first passes a wiping edge (9) at each wiping body (4), for stripping contaminants from its surface, and then is guided along a contact surface (10) of the wiping body (4) for cooling the metal wire (2) or the metal strip by means of the wiping body (4).

9. The method according to one of the preceding claims, wherein ceramic wiping bodies are used or wiping bodies (4) made of hard metal.

10. The method according to one of the preceding claims, wherein the metal wire (2) or the metal strip is made of copper or a copper alloy.

11. The method according to one of the preceding claims, wherein a substantially round metal wire is flat-profiled such that, as viewed in cross-section, it has two parallel flat sides, and directly after flat-profiling, first with a first of the two flat sides is guided under tensile stress in the longitudinal direction of the wire or the strip along a plurality of first wiping bodies arranged at a distance one behind the other in the longitudinal direction of the wire or the strip in such a way that the wire or the strip sections each lying between two successive first wiping bodies together form a bow-shaped wire section, in particular with the shape of a bow-shaped polygonal line, and directly thereafter with the other of the two flat sides is guided under tensile stress in the longitudinal direction of the wire or the strip along a plurality of second wiping bodies arranged at a distance one behind the other in the longitudinal direction of the wire or the strip in such a way that the wire or the strip sections each lying between two successive second wiping bodies together form a bow-shaped wire section, in particular with the shape of a bow-shaped polygonal line.

12. A device (1) for cleaning the surface of a metal wire (2) or a metal strip, in particular of a metal wire (2) or a metal strip used as an intermediate electrode of a roll seam welding machine, in particular according to the method according to one of the preceding claims, comprising a carrier body (3) with a plurality of wiping bodies (4), which are arranged one behind the other at a distance such that a metal wire (2) to be cleaned or a metal strip to be cleaned can be guided under tensile stress in the longitudinal direction of the wire or the strip along the wiping bodies (4) and the wire or the strip sections (5a-5g) each lying between two successive wiping bodies thereby together form a bow-shaped strip or wire section (5a-5g).

13. The device (1) according to claim 12, wherein the wiping bodies (4) are arranged one behind the other with a distance such that a metal wire (2) to be cleaned or a metal strip to be cleaned can be guided along the wiping bodies (4) under tensile stress in the longitudinal direction of the wire or the strip, and thereby the bow-shaped wire section formed by the wire or the strip sections (5a-5g) each lying between two successive wiping bodies has the shape of a bow-shaped polygon line.

14. The device (1) according to one of the claims 12 to 13, wherein the wiping bodies (4) are provided freely accessible on an outer side of the carrier body (3) in such a way that the metal wire (2) to be cleaned or the metal strip to be cleaned can be placed on the wiping bodies (4), in particular without tools.

15. The device (1) according to claim 14, wherein the carrier body (3) has an interior space (6) and wherein the distances between the wiping bodies (4) form passages (7) via which the interior space (6) is connected to the surroundings of the carrier body (3), and wherein, while the metal wire (2) or metal strip is guided along the wiping bodies (4) for the purpose of cleaning the surface of the metal wire (2) or the metal strip, the interior space (6) can be pressurized with negative pressure for extracting the contaminants (14) stripped off at the wiping bodies (4) via the interior space (6) of the carrier body (3).

16. The device (1) according to one of the claims 12 to 15, wherein guide elements (8), in particular guide pins (8), are arranged before and after the wiping bodies (4) arranged at a distance one behind the other, as seen in the longitudinal direction of the wire or the strip, by means of which the metal wire (2) or the metal strip can be guided transversely to its bearing direction on the wiping bodies (4), in particular in such a way that the metal wire (2) or the metal strip is guided over the wiping bodies (4) without running up in a lateral direction.

17. The device (1) according to one of the claims 14 to 15 and according to claim 16, wherein the guide elements (8) are provided in the carrier body (3).

18. The device (1) according to one of the claims 12 to 17, wherein the wiping bodies (4) are formed in such a way and wherein the metal wire (2) or the metal strip can be guided along the wiping bodies (4) in such a way that the metal wire (2) or the metal strip first passes a wiping edge (9) at each wiping body (4), for stripping contaminants (14) from its surface, and then is guided along a contact surface (10) of the wiping body (4) for cooling the metal wire (2) or the metal strip by means of the wiping body (4).

19. The device (1) according to one of the claims 12 to 18, wherein the wiping bodies (4) are made of hard metal or ceramic.

20. A use of the device (1) according to one of the claims 12 to 19 for cleaning a metal wire (2) or a metal strip made of copper or a copper alloy.