MXPA06006252A - Method and device for manufacturing sawtooth card clothing and all-steel card clothing as well as sawtooth wire - Google Patents

Abstract

In a method for manufacturing sawtooth card clothings and all-steel card clothings for processing textile fibers in a carding process, a sawtooth wire is produced by generating teeth on a wire blank sequentially behind one another in a longitudinal direction of the wire blank, wherein the teeth extend transversely to the longitudinal direction away from a base area. The sawtooth wire is subjected at least in the area of the teeth to a hardening process under exclusion of oxygen in the area of the sawtooth wire. A device for performing the method has a heating chamber having an inlet opening and an outlet opening for the sawtooth wire passing through the heating chamber. An arrangement for generating an inert gas atmosphere in the area of the sawtooth wire passing through the heating chamber is provided.

Description

METHOD AND DEVICE FOR MANUFACTURING CARDA GARNISHING SIERRA TOOTH AND CARNIVAL FILLING TOTALLY FROM STEEL AS WELL AS WIRE IN SAW TOOTH DESCRIPTIVE MEMORY The present invention relates to a process for manufacturing sawtooth card liners and all-steel card liners for processing textile fibers, particularly in the field of a carding process, in which a starting material is provided in the form of wire with teeth arranged successively in a longitudinal direction of the wire and extending, from a standing area, transversely to the longitudinal direction and the sawtooth wire thus generated, is subjected at least in the region of the teeth to a hardening procedure; a device for carrying out said method, as well as a sawtooth wire manufactured by such method. Sawtooth wires are used which are manufactured by the methods of the aforementioned type, consisting of unalloyed steels and alloyed steels, for example, in cards for treating textile fibers. For this purpose, the sawtooth wires can be mounted, for example, in a helical shape on a circular cylindrical support (drum) of the card.

In the case of modern cards, a sawtooth wire with a length of several kilometers is required to produce the sawtooth card garrison or steel garrison for the drum of a card. To process textile fibers, it is rotated about its axial axis to the card drum with its wire card lining there arranged so that the card lining can traverse and clean the fiber material fed to the drum; the drum card lining cooperates with flat cards fixed or driven in opposite manner, each provided with a respective flat card lining. In this type of fiber processing and in order to obtain a satisfactory carding result and to avoid damage to the card, it must be ensured that the sawtooth wires are mounted with great accuracy on the circular cylindrical support so that there are no variations in the radial separation of the tips of the sawtooth wires from the axis of rotation of the drum, which could adversely affect the result of the carding or the reliability of operation, since even the local inaccuracies that occur during the assembly of the wire Sawtooth on the drum can cause deterioration of the sawtooth card linings or formed all-steel card linings that may require a total replacement. This involves a high cost in modern high-performance carding machines with respect to the downtime of the machine and the materials required. Furthermore, in order to ensure a satisfactory quality of carding, it is also necessary to avoid a random axial displacement of the successively arranged windings. To obtain a satisfactory service life of a card, it must also be ensured that there is no excessive wear of the sawtooth wires. For this purpose, the teeth of the sawtooth wires that will be mounted on the drum are subjected to a hardening procedure. They can be heated by way of example by means of a direct flame at their austenitization temperature, respectively, and can then be quenched. In particular, during the heating of the wire, a layer of scale or oxide of varying thickness can be formed on the wire. This layer is particularly problematic in terms of the accuracy required for the card lining mounted in a helical shape on the support. The sawtooth wire is mounted on the rotating support by means of a wire mounting device. To ensure the necessary mounting precision, the wire has to pass through narrow guides. During this process, scale particles can be detached from the wire surface and deposited in the mounting device, and especially in the guides, due to bending and friction of the wire in the guides. Such contamination of the guides can strongly affect the quality of assembly of the wire and the speed at which the assembly of the wire is carried out. In addition, due to the detachment of the scale particles, it is necessary to frequently interrupt the wire assembly process in order to be able to clean the wire assembly device and, particularly, its guides. In case these cleaning interruptions are not carried out in time, the tensile forces acting on the wire that increase due to the increasing contamination of the guides, can be raised to such a degree that the wire breaks. Taking into account these problems, it has already been proposed to eliminate the scale or rust layers produced during curing after the hardening process. For this purpose, for example abrasive methods are known, in which the wires are brushed with rotating metal brushes after the hardening process, to eliminate as much as possible the adhering scale. In another method, the wire is rectified by means of profiled grinding wheels to remove the layer of scale. Finally, chemical methods are also known to chemically remove the husk layer. However, the methods for removing the layer of scale that have been proposed by virtue of the aforementioned problems, have the disadvantage that as a result of the mechanical or chemical removal of the material, the wire itself is also damaged to a greater or lesser degree . In addition, the removal of the layer of scale made to avoid the problems with respect to the assembly of the wire, can also lead to the flanks and the tips of the teeth of the sawtooth wire being rounded so that the teeth lose part of their desired edge.

In view of these problems, it is an object of the present invention to provide a method for manufacturing sawtooth card liners and all-steel card liners to treat textile fibers, with which card liners can be produced quickly and reliably. without affecting the quality of the card garrison. According to the present invention, this is achieved by carrying out a hardening process with exclusion of oxygen in the area of the sawtooth wire, wherein the sawtooth wire preferably passes through a heating chamber. Through the method according to the invention, from the beginning the layer of scale or oxide due to the exclusion of oxygen during the hardening process is avoided, so that pollution problems that lead to deterioration and slowing down do not occur. of the wire assembly process when wires produced according to the known methods are employed, and so that a deterioration in the quality of the sawtooth wire is not expected due to the necessary removal of the layer of scale. oxide. Furthermore, with the sawtooth wire card liners and all-steel card liners according to the present invention, an improved quality of the carded fibers can be ensured, since the card linings manufactured according to the prior art, In spite of the measures described, in many cases they still have particles of scale which, during the treatment of fibers, are detached from the card linings and can contaminate the textile fibers. In the case of card linings manufactured in accordance with conventional methods, this leads to a deterioration of the carding results and a reduction in the service life of the card liners since the particles of peel off also cause wear and tear. additional carda garrisons. These problems are basically solved by the method of the invention because the formation of scale on the surface of the sawtooth wire does not take place. In the method according to the present invention, the teeth of the sawtooth wire can be heated in the course of the curing process, in the same manner as in prior art methods, to an austenitization temperature preferably of about 500-1200 ° C, particularly about 800-1000 ° C, optionally after preheating to for example 500-800 ° C, and subsequently they can be rapidly cooled. The subsequent cooling process (abrupt cooling) of the sawtooth wire preferably also takes place under the exclusion of oxygen or other oxidizing gases. Conveniently, for the cooling step use is made of an abrupt cooling bath, which can be operated with water, an oil and water or oil emulsion, the sawtooth wire, in continuous operation, first heated and then cooled in the abrupt cooling bath.

The cooling takes place advantageously in an oil bath to avoid the formation of cracks due to stresses in the wire. In a particularly preferred embodiment of the present invention, the sawtooth wires can be annealed, that is, subjected to an additional heat treatment, to reduce the friability still present despite the use of an oil bath for sudden cooling or good to increase tenacity. This additional heat treatment process is also advantageously carried out under the exclusion of oxygen or other oxidizing gases in the area of the teeth that will be hardened. In the method according to the invention, the heating of the sawtooth wires at the austenitization temperature can be performed, ensuring continuous operation within the context of a continuous production process, by the fact that at least the teeth of the sawtooth wire pass through a flame at least during heating in the context of the hardening process. In this regard, the flame, in order to ensure the exclusion of oxygen in the area of the sawtooth wire, according to the present invention, is generated in an atmosphere of inert gas, for example, a nitrogen atmosphere. The exclusion of desired oxygen can be ensured in this respect since, in order to generate the flame, a combustion gas and an oxidizing medium, such as oxygen, are introduced into the heating chamber in such a way that the oxidizing medium is never in contact with the oxygen. the teeth that will be hardened and preferably reacted completely during the combustion process to produce the flame. When carrying out the method according to the invention, therefore, the flame used for heating the wire without excess oxygen is conveniently generated. The undesired contact of the teeth with the oxygen in the air can be substantially excluded when the heating chamber is subjected to a flow of inert gas, where an overpressure of inert gas is conveniently maintained in the heating chamber. Sawtooth wires manufactured according to the method of the invention should be provided in the area of their teeth or the tips of the teeth with a particularly high hardness to achieve a satisfactory service life. On the other hand, these sawtooth wires must have a deformation capacity such that they can be mounted helically on the circular cylindrical support even in their foot zone. In this regard, the microstructure of the sawtooth wires at the tip of the tooth is usually constituted by martensite and in the foot zone, by ferrite with embedded cementite (globular). To obtain the desired structure in the standing area, at the time of carrying out the method according to the invention, the sawtooth wires are conveniently annealed (spheroidized) before the hardening process at least within the area standing. The flame used in the course of the hardening process is conveniently adjusted to ensure the desired microstructure in the foot region so that the heating is effected only in the area of the saw teeth and particularly in the tooth tips. . The wire-shaped starting material used within the method of the present invention is conveniently provided in the form of cold-rolled shaped sections to obtain the desired cross-sectional shape of the wires. When carrying out the method of the invention, preferably two different gas systems are used. A system is provided for the regulated and controlled introduction of the inert gas and a second system for the introduction of a predetermined mixture of oxygen and combustion gas to the burner or to the heating chamber. In this regard, the inert gas, depending on the operating state and the position of the burner (start-up, stopping, etc.), is controlled with respect to the amount and pressure in the heating chamber. The mixture of the combustion gas and the oxidizing medium and the geometry of the burners are selected so that the teeth do not come into contact with unburned oxygen so that no scale is formed when passing through the flame. In addition, the introduction of the inert gas and the resultant flow conditions contribute to avoiding contact between the oxidizing medium and the teeth. Wires for all-steel card liners manufactured in accordance with the present invention have the following advantages compared to wires manufactured with conventional methods.

The card-garrison wires that are manufactured in accordance with the present invention are free of scale, so that scale debris can not be deposited on the guides of the wire-mounting devices. In the end, this means that by means of the wires manufactured with the inventive method a substantially higher wire assembly speed can be achieved than by the all-steel card-wrapping wires manufactured by conventional methods. Additionally, interruptions of the wire assembly process are not necessary for cleaning the guides and the wire mounting device when the wire produced in accordance with the method of the present invention is used. In addition, seizure and breakage of the wire in the guides is safely avoided. Another advantage of the card linings manufactured with the method according to the invention is that when using card liners made with shellac-free wire, contamination of the textile fibers by means of scale residues is totally avoided. In this regard, it is desired to emphasize that the described disadvantage of textile fiber contamination due to scale residues can also be largely avoided through the use of brushed or polished wires by abrasive discs. However, the wires manufactured by these known methods have the great disadvantage that the grinding or polishing also undesirably round the edges and tips, so that the card garrison wire significantly loses edge edges. desired for its use and that, therefore, its carding performance is considerably reduced compared to untreated wires. The same disadvantages also apply for chemically treated wires. As is clear from the above explanations of the method according to the invention, a device for carrying out the method according to the present invention comprises a hardening chamber with an inlet opening and an outlet opening for a tooth wire of saw passing through said chamber and an arrangement for generating an inert gas atmosphere in the area of the teeth of the sawtooth wire passing through the chamber. To obtain the necessary heating for the hardening process of the teeth, the device may have a burner arrangement for generating a flame in the area of the teeth of the sawtooth wire passing through the chamber. To generate a mixture that ensures as much as possible the exclusion of oxygen in the area of the teeth, the burner arrangement can have a mixing device with which a combustion gas and an oxidizing medium, for example oxygen, can be mixed. according to a predetermined ratio before the mixture thus prepared reacts or is burned to obtain the flame. Additionally, the chamber may be equipped with a nozzle arrangement for introducing the inert gas. By means of this arrangement of nozzles, the inert gas is advantageously introduced so that an overpressure of inert gas takes place in the chamber, by means of the inert gas conduit it is further ensured that the oxidizing medium or the oxygen will not be in contact with the teeth of the sawtooth wire. The heating chamber of a device according to the present invention may have an arrangement for cooling the heated teeth under the current. This arrangement advantageously comprises an oil bath through which the sawtooth wire passes under the exclusion of oxygen. Further, in accordance with the present invention, an annealing device may be arranged to anneal the sawtooth wires in the direction of travel of the wire upstream of the chamber. In the context of the method according to the invention, the starting material in wire form is usually provided with teeth by a stamping or die cutting process. A sawtooth wire manufactured in accordance with the method of the present invention, is substantially characterized in that it has hardened teeth, which do not exhibit scale residues or rounded edges produced by a mechanical rectification process or a chemical process. In the description given above, the method according to the invention has been explained with respect to the manufacture of card linings for the drum of a carding device. Additionally, the method according to the invention can also be used for the manufacture of card linings for taker cylinders or the like. The present invention will now be described in more detail with reference to FIG. 1, with specific reference to illustrated features not explained in detail in the description, but which are important for the invention. Figure 1 shows a schematic illustration of an appropriate device for carrying out the method according to the invention. The device illustrated in the drawing comprises a tubular shaped chamber designated generally with the reference 20, in which the sawtooth wire 10 is transported in the direction indicated by the arrow P. The wire passes in the first place by a preheating device 30, in which it is preheated inductively at a temperature between 500 ° C to 800 ° C. After leaving the preheating device, an inert gas is supplied in the tubular chamber 20 by a corresponding inert gas introducing device 40. Downstream of the inert gas introducing device 40, the wire 10 now transported through an atmosphere of inert gas is heated in the area of the teeth to the austenitizing temperature by means of a burner device 50 under the exclusion of oxygen. For this purpose, a flame is generated in the area of the teeth inside the combustion chamber 50. The suitable burner arrangement has a mixing device, with which the combustion gas and the oxidizing medium are introduced into the burner chamber 50 in such a way that the oxidizing medium is reacted or burned completely by combustion and does not come into contact with the teeth of the sawtooth wire. Downstream of the burner chamber 50, the sawtooth wire 10 passes through a quench device 60.

Claims (14)

j NOVELTY OF THE INVENTION CLAIMS

1. - A method for manufacturing sawtooth card liners and all-steel card liners for processing textile fibers, particularly in a carding process, where a sawtooth wire is produced when generating teeth on a starting material in wire form successively one behind the other in a longitudinal direction of the wire-shaped starting material, wherein the teeth each extend transverse to the longitudinal direction from a foot area, and the wire Sawtooth is subjected at least in the area of the teeth, to a hardening procedure under the exclusion of oxygen in the area of the sawtooth wire, where the sawtooth wire preferably passes through a chamber of heating.

2. The method according to claim 1, further characterized in that the sawtooth wire is heated during the curing process and possibly after preheating, at an austenitization temperature of preferably from about 500 ° C to 1200 ° C, particularly about 800 ° C to 1000 ° C, and subsequently it is rapidly cooled.

3. The method according to claim 2, further characterized in that the sawtooth wire, after cooling, is annealed to reduce friability or increase toughness, preferably also under the exclusion of oxygen.

4. The method according to one of the preceding claims, further characterized in that at least the teeth of the sawtooth wire are displaced through a flame at least during heating in the hardening process.

5. The method according to claim 4, further characterized in that the flame is generated in an atmosphere of inert gas, such as a nitrogen atmosphere.

6. The method according to claim 4 or 5, further characterized in that to generate the flame, a combustion gas and an oxidizing medium, such as oxygen, are introduced into a heating chamber in such a way that the oxidizing medium does not It makes contact with the teeth that will be hardened and preferably the oxidizing medium reacts completely in a combustion process to generate the flame produced by the combustion process.

7. The method according to one of the preceding claims, further characterized in that an inert gas flows through the heating chamber.

8. The method according to one of the preceding claims, further characterized in that the heating chamber is filled with inert gas at overpressure to prevent the entry of atmospheric oxygen.

9. The method according to one of the preceding claims, further characterized in that the sawtooth wire is annealed at least in a standing area before performing the hardening procedure.

10. A device for carrying out the method of one of the preceding claims, with a heating chamber having an inlet opening and an outlet opening for a sawtooth wire that travels through the chamber heating, and an arrangement for generating an inert gas atmosphere in the tooth region of the sawtooth wire passing through the heating chamber.

11. The device according to claim 10, further characterized in that the heating chamber is equipped with a burner arrangement for generating a flame in the area of the teeth of the sawtooth wire that passes through the chamber. heating.

12. The device according to claim 11, further characterized in that the burner arrangement has a mixing device, in which a combustion gas and an oxidizing medium, such as oxygen, can be mixed according to a predetermined ratio before that the mixture reacts in the heating chamber to generate the flame.

13. The device according to one of claims 10 to 12, further characterized in that the chamber is equipped with a nozzle arrangement for introducing the inert gas.

14. A sawtooth wire manufactured by a method of claims 1 to 9.