METHOD FOR OPERATING A SPINNING STATION OF A ROTOR SPINNING MACHINE AND ROTOR SPINNING MACHINE

Abstract

A method for operating a spinning station of a rotor spinning machine includes monitoring the yarn being and upon detection of a yarn defect, stopping the spinning station and removing the yarn defect. The method specifies a certain produced yarn length or a certain time interval of yarn production and a maximum number of yarn defects within the produced yarn length or time interval. Upon detecting and exceeding a maximum number of yarn defects within the produced yarn length or the time interval, a mechanical cleaning of the spinning rotor is carried out. Alternately, a certain minimum produced yarn length or a certain minimum time interval between two yarn defects is specified and the produced yarn length or time between detection of the yarn defects is recorded. Upon undershooting the minimum produced yarn length or minimum time interval between yarn defects, the mechanical cleaning of the spinning rotor is performed.

Claims

1-12: (canceled)

13. A method for operating a spinning station of a rotor spinning machine that produces a yarn with a spinning rotor, the method comprising: monitoring the yarn being produced via a yarn monitoring unit; upon detection of a yarn defect by the yarn monitoring unit, stopping the spinning station and removing the yarn defect from the yarn; cleaning the spinning rotor with a spinning station-specific first cleaning device and then re-piecing the yarn at the spinning station; specifying a certain produced yarn length or a certain time interval of yarn production; specifying a maximum number of yarn defects within the produced yarn length or the time interval; detecting the number of yarn defects within the produced yarn length or the time interval; and upon exceeding a specified maximum number of yarn defects within the produced yarn length or the time interval, carrying out a mechanical intensive cleaning of the spinning rotor.

14. The method of claim 13, wherein the yarn defects are subdivided into multiple types of yarn defects and the number of the yarn defects within the produced yarn length or the time interval are recorded separately for the multiple types of yarn defects.

15. The method of claim 14, wherein the maximum number of yarn defects within the produced yarn length or the time interval is separately specified for the multiple types of yarn defects.

16. The method of claim 13, wherein the yarn defect is a Moiré effect.

17. The method of claim 13, wherein the mechanical intensive cleaning of the spinning rotor is carried out by a second cleaning device that is different from the first cleaning device.

18. The method of claim 13, wherein the second cleaning device is configured on a maintenance unit that travels along multiple spinning stations of the rotor spinning machine.

19. The method of claim 13, wherein the second cleaning device a spinning station-specific cleaning device.

20. The method of claim 13, wherein the yarn is re-pieced by a spinning station-specific piecing device.

21. A method for operating a spinning station of a rotor spinning machine, comprising, wherein a yarn is produced at the spinning station with a spinning rotor, the method comprising: monitoring the yarn produced at the spinning station with a yarn monitoring unit; wherein, upon detection of a yarn defect in the yarn by the yarn monitoring unit, stopping the spinning station and removing the yarn defect from the yarn; cleaning the spinning rotor with a spinning station-specific cleaning device and then re-piecing the yarn at the spinning station; specifying a certain minimum produced yarn length or a certain minimum time interval between two yarn defects; recording the produced yarn length or time between detection of the yarn defects; and upon undershooting the minimum produced yarn length or minimum time interval between two yarn defects, carrying out a mechanical intensive cleaning of the spinning rotor.

22. The method of claim 21, wherein the mechanical intensive cleaning is carried out only after the minimum produced yarn length or the minimum time interval between two yarn defects has not been met a specified multiple number of times.

23. The method of claim 21, wherein the yarn defects are subdivided into multiple types of yarn defects and the number of the yarn defects within the minimum produced yarn length or the minimum time interval between two yarn defects is recorded separately for the multiple types of yarn defects.

24. The method of claim 23, wherein the minimum produced yarn length or the minimum time interval between two yarn defects is separately specified for the multiple types of yarn defects.

25. The method of claim 21, wherein the yarn defect is a Moiré effect.

26. The method of claim 21, wherein the mechanical intensive cleaning of the spinning rotor is carried out by a second cleaning device that is different from the first cleaning device.

27. The method of claim 21, wherein the second cleaning device is configured on a maintenance unit that travels along multiple spinning stations of the rotor spinning machine.

28. The method of claim 21, wherein the second cleaning device a spinning station-specific cleaning device.

29. The method of claim 21, wherein the yarn is re-pieced by a spinning station-specific piecing device.

30. A rotor spinning machine, comprising: a plurality of adjacently arranged spinning stations; each spinning station comprising: a spinning rotor for producing a yarn; a yarn monitoring unit for monitoring the produced yarn; a spinning station-specific cleaning device for cleaning the spinning rotor; and a control unit configured to control performance of the following: monitoring the yarn being produced via the yarn monitoring unit; upon detection of a yarn defect by the yarn monitoring unit, stopping the spinning station and removing the yarn defect from the yarn; cleaning the spinning rotor with the spinning station-specific cleaning device and then re-piecing the yarn at the spinning station; specifying a certain produced yarn length or a certain time interval of yarn production; specifying a maximum number of yarn defects within the produced yarn length or the time interval; detecting the number of yarn defects within the produced yarn length or the time interval with the yarn monitoring unit; and upon exceeding a specified maximum number of yarn defects within the produced yarn length or the time interval, carrying out a mechanical intensive cleaning of the spinning rotor with a further cleaning device.

31. A rotor spinning machine, comprising: a plurality of adjacently arranged spinning stations; each spinning station comprising: a spinning rotor for producing a yarn; a yarn monitoring unit for monitoring the produced yarn; a spinning station-specific cleaning device for cleaning the spinning rotor; and a control unit configured to control performance of the following: monitoring the yarn being produced via the yarn monitoring unit; upon detection of a yarn defect by the yarn monitoring unit, stopping the spinning station and removing the yarn defect from the yarn; cleaning the spinning rotor with the spinning station-specific cleaning device and then re-piecing the yarn at the spinning station; specifying a certain minimum produced yarn length or a certain minimum time interval between two yarn defects; recording the produced yarn length or time between detection of the yarn defects; and upon undershooting the minimum produced yarn length or minimum time interval between two yarn defects, carrying out a mechanical intensive cleaning of the spinning rotor with a further cleaning device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Further advantages of the invention are described in the following exemplary embodiments, wherein:

[0032] FIG. 1 shows a schematic front view of a rotor spinning machine according to a first embodiment,

[0033] FIG. 2 shows a schematic front view of a rotor spinning machine according to a second embodiment,

[0034] FIG. 3 shows a schematic, partially cut side view of a spinning station of a rotor spinning machine according to a first embodiment,

[0035] FIG. 4 shows a schematic, partially cut side view of a spinning station of a rotor spinning machine according to a second embodiment, and

[0036] FIG. 5 shows a schematic, partially cut side view of a spinning station of a rotor spinning machine that includes a displaceable maintenance unit located in front thereof.

DETAILED DESCRIPTION

[0037] Reference will now be made to embodiments of the invention, one or more examples of which are shown in the drawings. Each embodiment is provided by way of explanation of the invention, and not as a limitation of the invention. For example features illustrated or described as part of one embodiment can be combined with another embodiment to yield still another embodiment. It is intended that the present invention include these and other modifications and variations to the embodiments described herein.

[0038] In the following description of the figures, the same reference signs are used for features that are identical and/or at least comparable in each of the various figures. The individual features, their embodiment and/or mode of operation are explained in detail usually only upon the first mention thereof. If individual features are not explained in detail once more, their embodiment and/or mode of operation correspond/corresponds to the embodiment and mode of operation of the features that act in the same way or have the same name and have already been described. Moreover, for the sake of clarity, often only one or only a few of several identical components and/or features is/are labeled.

[0039] FIG. 1 shows a schematic front view of a rotor spinning machine 1 according to a first embodiment. The rotor spinning machine 1 has a plurality of adjacently arranged spinning stations 2, of which only two are labeled in the present case. The spinning stations 2 are each arranged between two frames 3 generally on two longitudinal sides of the rotor spinning machine 1. Each of the spinning stations 2 has a supply unit 4 for feeding a fiber material 22 to a spinning device 7. In the spinning device 7, a yarn 8 is spun from the fiber material 22, the yarn 8 being drawn off by a take-off device 9 and fed to a winding device 12, where it is wound onto a package 13. In the present example, the yarn also passes through a waxing unit 11. The rotor spinning machine 1 also includes a central control unit 19 for controlling the functions of the rotor spinning machine 1 and/or the spinning stations 2. Moreover, according to the present representation, each of the spinning stations 2 also includes another spinning station-specific control unit. i.e., the workstation control system 20.

[0040] In the present case, a yarn monitoring unit 10 is arranged underneath the take-off device 9 at each of the spinning stations 2. By means of the yarn monitoring unit 10, the yarn 8 can be checked for yarn defects, such as thin and thick places, Moiré effects, and other defects. If a yarn defect is detected by the yarn monitoring unit 10, the yarn monitoring unit 10 triggers a so-called clearer cut. In a clearer cut, the moving yarn is cut and the defective yarn piece already traveling on the package is unwound counter to the regular winding direction, re-cut, and drawn out. Next, the yarn defect is cut out and the yarn 8 can be re-pieced. Generally, a rotor cleaning is carried out prior to the piecing. For this purpose, the spinning stations 2 each have a spinning station-specific cleaning device 16 (see FIG. 3), which is not shown here.

[0041] FIG. 2 shows another embodiment of a rotor spinning machine 1, which, in contrast to the rotor spinning machine 1 from FIG. 1, includes a maintenance unit 21, which is displaceable along the spinning stations 2. The displaceable maintenance unit 21 also has a control unit 19, which is connected to the central control unit 19 of the rotor spinning machine 1, as indicated by the dash-dotted line. Moreover, the displaceable maintenance unit 21 includes a further cleaning device 18 for carrying out a rotor cleaning. For the rest, the rotor spinning machine 1 corresponds to the rotor spinning machine from FIG. 1 and, therefore, is not explained in greater detail at this point.

[0042] FIG. 3 shows a schematic, partially cut side view of a spinning station 2 of a rotor spinning machine 1 according to a first embodiment. It is apparent that the fiber material 22 is fed to the spinning device 7 by means of the supply unit 4, which includes a feed roller 5 and an opening roller 6, and, at the spinning device 7, the fiber material 22 is fed to a spinning rotor 23. The present spinning station 2 is also designed as an autonomous spinning station 2, which can automatically carry out a spinning start-up process at least after a clearer cut. The individual working elements of the spinning station, which were described above with reference to FIG. 1, each have a separate drive 15, and so each spinning station 2 can be operated independently of the others. For this purpose, the working elements, i.e., the feed roller 5, the opening roller 6, the spinning rotor 23, the yarn monitoring unit 10, the take-off device 9, the winding device 12, and their drives 15 are connected to the workstation control system 20 for control purposes, the workstation control system 20 being connected in turn to the central control unit 19 of the rotor spinning machine 1. The spinning station 2 also has a spinning station-specific piecing device (not shown) for automatically carrying out a piecing operation. The spinning station-specific piecing device includes at least one unit for returning the yarn end into the spinning rotor 32, for example, a blowing unit.

[0043] Each of the spinning stations 2 also includes a spinning station-specific cleaning device 16, which is pneumatic in this case, for rotor cleaning. The spinning station-specific cleaning device 16 includes a blowing nozzle 17, which is arranged, in the present case, in a cover element 14, which closes the spinning device 7 during operation. The cover element 14 is arranged to swivel at the spinning station 2 in a known way. The blowing nozzle 17 is connected to a compressed air source 25 via a compressed air line 26. A coupling 24 is also provided in the compressed air line 26 in order to enable the swiveling of the cover element 14.

[0044] As described above, as soon as a yarn defect has been detected by the yarn monitoring unit 10, a clearer cut is triggered. The yarn defect is cut out and, thereafter, the yarn 8 is re-pieced. The piecings meet the quality requirements on the yarn, in principle, and so the piecings are generally not detected as yarn defects. Nevertheless, each piecing forms a thick place in the yarn. For this reason, problems can arise when the yarn 8 contains too many piecings. On the one hand, the quality of the yarn 8 suffers. On the other hand, bulges can form on the packages 13 when a plurality of piecings have been wound onto the package 13. The number of piecings on the package 13 should therefore not be too high.

[0045] For this reason, the aim is to reduce the number of clearer cuts and, therefore, the number of piecings by means of a regular rotor cleaning. For this reason, a rotor cleaning generally also takes place by means of the spinning station-specific pneumatic cleaning device 16 after a clearer cut.

[0046] The rotor cleaning can be carried out comparatively quickly by means of the spinning station-specific cleaning device 16, since, for example, in the case of a pneumatic cleaning device 16, only one valve (not shown) of the cleaning device 16 needs to be actuated for this purpose, in order to trigger a blast. The production losses due to the spinning device 7 being stopped during the rotor cleaning can be kept low as a result. A fast standard cleaning of the spinning rotor 23 is also possible in the case of a spinning station-specific mechanical cleaning device 16. If the cleaning by the spinning station-specific cleaning device 16 is insufficient, however, or if new dirt quickly arises due to the current use, further yarn defects can quickly arise despite the rotor cleaning having been carried out. As a result, the number of clearer cuts and, thereby, also the number of piecings increases, as the result of which the quality of the yarn 8 and of the package 13 can be adversely affected.

[0047] For this reason, it is provided to carry out a mechanical intensive cleaning of the spinning rotor by means of a mechanical cleaning device 16, 18 as soon as yarn defects arise again within short intervals after the piecing. The intervals can be based on yarn length distances and on time intervals. Due to the intensive cleaning, the rotor groove is intensively cleaned and freed from any adhesions, so that accumulations of yarn defects can be avoided. If necessary, an intensive cleaning of this type can also be repeated, i.e., for example, after three consecutive clearer cuts. Preferably, the operator can specify this in the central control unit 19 or the workstation control system 20 of the relevant spinning station 2. Due to the mechanical rotor cleaning, which is carried out only in the case of a high occurrence of yarn defects, the quality of the yarn 8 and of the package 13 can be improved, on the one hand, and the production losses due to the downtimes of the spinning station 2 can nevertheless be kept low.

[0048] In order to detect an accumulation of yarn defects, according to a first embodiment of the method, a maximum permissible number of yarn defects within a certain produced yarn length can be specified. The yarn defects detected by the yarn monitoring unit are registered and counted by the workstation control system 20 or the central control unit 19. If the maximum permissible number of yarn defects within the certain yarn length is exceeded, the mechanical intensive cleaning of the spinning rotor 23 is triggered by the control unit 19 or the workstation control system 20. Instead of the certain produced yarn length, a certain time interval can also be specified, within which only a certain number of yarn defects is permitted to arise.

[0049] Alternatively, it is also possible to specify a certain minimum produced yarn length and/or a certain minimum time interval between two yarn defects. The yarn defects detected by means of the yarn monitoring unit are registered by the workstation control system 20 or the central control unit 19 and, additionally, the produced yarn length upon detection of the yarn defects and/or the point in time of the detection of the yarn defects are/is also recorded. By means of the workstation control system 20 or the central control unit 19, the actually produced yarn length or the actual time interval between two yarn defects are compared with the predefined minimum yarn length and the predefined minimum time interval, respectively. If the predefined minimum yarn length and/or the predefined minimum time interval are/is fallen below, the mechanical intensive cleaning of the spinning rotor is in turn triggered.

[0050] According to a first embodiment of the method, the mechanical intensive cleaning is carried out by a further cleaning device 18, which is also arranged at the spinning station 2. FIG. 4 shows a schematic, partially cut side view of such a spinning station 2 that includes a spinning station-specific, further cleaning device 18. The further cleaning device 18 in the present example is arranged at the cover element 14, more precisely in an extension of the third element. The further cleaning device 18 can be designed, for example, as an extendable scraper, as shown in FIG. 4.

[0051] Alternatively, a brush or another mechanical cleaning element would also be conceivable. It is also not absolutely necessary that the further mechanical cleaning device 18 is arranged at the cover element 14. It would also be possible to arrange the further cleaning device at the spinning station 2 so as to be movable and advanceable toward the spinning rotor 23. In this case, the cover element 14 would have to be first swiveled away, in order to advance the further cleaning device 18 toward the spinning rotor 23.

[0052] Moreover, it would also be conceivable to arrange only a single mechanical spinning station-specific cleaning device 16 at the spinning station, which carries out a standard cleaning in each case of piecing and also carries out a mechanical intensive cleaning as described above when there is a high accumulation of yarn defects.

[0053] According to another embodiment of the method, the mechanical intensive cleaning is carried out by a further cleaning device 18, which is arranged in a maintenance unit 21, which is displaceable along the spinning stations 2 of the rotor spinning machine 1. The configuration of a rotor spinning machine 1 of this type is shown in FIG. 2.

[0054] FIG. 5 shows a schematic, partially cut side view of a spinning station 2 of such a rotor spinning machine 1 that includes a displaceable maintenance unit 21 located in front thereof. In the present example, the cover element 14 of the spinning device 7 has already been swiveled opened in order to enable the mechanical rotor cleaning. The swiveling of the cover element 14 can be carried out by the maintenance unit 21 and also by the spinning station 2 itself. The further cleaning device 18 in the present case is designed as a cleaning head that is advanceable toward the spinning rotor 23, the cleaning head also being provided with extendable scrapers. In the representation shown, the cleaning device 18 has already been advanced toward the spinning rotor 23 and the scrapers have already been extended.

[0055] In order to achieve optimal production while simultaneously ensuring a good yarn and package quality, it is advantageous when the parameters that define an accumulation of yarn defects can be specified in the control unit of the rotor spinning machine 19 or, if necessary, also in the workstation control system 20 individually for each spinning station 2. As described above, the parameters include the certain produced yarn length and/or the duration of the time interval and the maximum number of yarn defects or the minimum produced yarn length and/or the minimum time interval between two yarn defects and, if necessary, the permissible number of undershootings of the minimum produced yarn length and/or of the minimum interval. Preferably, this can be specified by the user him/herself, although it is possible for the manufacturer to fixedly program this into the appropriate control unit 19. Particularly advantageously, these parameters are specified separately for various types of yarn defects. This also makes it possible, for example, to carry out a time-intensive mechanical rotor cleaning only for the case in which the same yarn defect frequently arises.

[0056] The present invention is not limited to the represented and described exemplary embodiments. Modifications within the scope of the claims are also possible, as is any combination of the features, even if they are represented and described in different exemplary embodiments.

LIST OF REFERENCE SKINS

[0057] 1 rotor spinning machine [0058] 2 spinning station [0059] 3 frame [0060] 4 supply unit [0061] 5 feed roller [0062] 6 opening roller [0063] 7 spinning device [0064] 8 yarn [0065] 9 take-off device [0066] 10 yarn monitoring unit [0067] 11 waxing unit [0068] 12 winding device [0069] 13 package [0070] 14 cover element [0071] 15 drive [0072] 16 spinning station-specific cleaning device [0073] 17 blowing nozzle [0074] 18 further cleaning device [0075] 19 control unit [0076] 20 workstation control system [0077] 21 maintenance unit [0078] 22 fiber material [0079] 23 spinning rotor [0080] 24 coupling [0081] 25 compressed air source [0082] 26 compressed air line