Method for determining the weight of a cross coil

Abstract

The invention relates to a method for determining the weight of a cross-wound bobbin (5) produced on a textile machine (1) with a plurality of workstations (2), each of which has a winding device (4) for laying a thread on the cross-wound bobbin (5) and a capacitive thread cleaner (21) arranged in the area of ​​the thread path, which cleans out undesirable mass deviations of the thread (16) during the winding process. In order to enable the operator of a cross-wound bobbin-producing textile machine (1) to gain insight into the production output of the textile machine, the weight of the cross-wound bobbins (5) produced at the workstations of the textile machine should be predictable and as uniform as possible with respect to their bobbin weights.To solve the problem described above, the invention provides that the thread cleaner (21) successively scans the yarn mass of a running thread (16) and yarn mass values ​​are determined, and that, to determine the weight of the cross-wound bobbin (5), values ​​are determined from the yarn scans of the thread cleaner (21) which are summed over the yarn production length of the cross-wound bobbin (5).

Description

[0001] The invention relates to a method for determining the weight of a cross-wound bobbin produced on a textile machine with a plurality of workstations. The workstations each have a winding device for laying a thread on the cross-wound bobbin and a capacitive thread cleaner arranged in the region of the thread path, which removes undesirable mass deviations of the thread during the winding process. The invention also relates to a textile machine producing cross-wound bobbins for implementing the method.

[0002] Such cross-wound bobbin-producing textile machines are designed, for example, as cross-wound bobbin winders, which have a plurality of workstations, each of which has an unwinding position for a supply bobbin, a capacitive thread cleaner located in the area of ​​the thread path, which removes unwanted mass deviations of the thread (so-called thread defects) during the winding process, a calculating device, and a winding device. Such cross-wound bobbin-producing textile machines can also be designed as rotor spinning machines or air-jet spinning machines, which also have a corresponding winding device.

[0003] In connection with the operation of textile machines producing cross-wound bobbins, operators generally require that the cross-wound bobbins produced on the workstations of such textile machines always have either a virtually identical thread length or a virtually identical diameter. Corresponding devices and methods that ensure that this requirement is met are known and described in various patent documents.

[0004] For example, DE 42 25 842 A1 describes a device or method in which the speed of the running thread is determined using a runtime correlator, which is then directly evaluated by an integrator to determine the cumulative running length of the textile thread wound into a cross-wound bobbin at the workstation. This means that this known device enables the production of cross-wound bobbins that always have the same thread length.

[0005] DE 102 06 761 A1 and DE 196 25 512 A1 describe devices and methods for producing cross-wound bobbins which each have the same diameter.

[0006] For example, DE 102 06 761 A1 discloses a textile machine whose workstations each have a winding device equipped with a bobbin frame mounted for limited rotation, which has a measuring device that records the diameter of the resulting cross-wound bobbin during the winding process. The known measuring device is equipped with a sensor coupled to one of the bobbin frame arms via a transmission device in such a way that even a relatively small deflection of the bobbin arm leads to a larger deflection of a measuring element of the sensor. The measured value of the sensor is then used by a processing station to calculate the cross-wound bobbin diameter.

[0007] DE 196 25 512 A1 describes a method by which the diameter of a cross-wound bobbin driven by a friction roller can be determined during its production.

[0008] In this known method, the angular velocity of the cross-wound bobbin is used, among other things, to determine the cross-wound bobbin diameter. This means that the diameter of the cross-wound bobbin is calculated by dividing the circumferential velocity of the surface of the cross-wound bobbin by the angular velocity of the cross-wound bobbin. The circumferential velocity is calculated from sensor signals from two sensors measuring consecutive surface features of the cross-wound bobbin at a fixed distance in the circumferential direction of the cross-wound bobbin using a transit-time correlation method.

[0009] Furthermore, it is known to determine the approximate weight of a package during production using the yarn count and the yarn production length. However, this is problematic because not only can the yarn count of the supply packages, usually spinning bobbins produced on ring spinning machines, vary, for example, due to tolerances occurring during the spinning process on the ring spinning machine or differences in the roving bobbins already used, but also because the yarn production length, which is determined, for example, by the revolutions of the package's drive drum, is often inaccurate. This means that a specific yarn production length is assumed for each drum revolution.However, this specific yarn production length can often differ from the actual yarn length produced due to production-related conditions, such as slippage and thread tension, with the result that the weights of the cross-wound bobbins produced can also vary considerably.

[0010] EP 2 664 571 A2 discloses a method for determining the weight of a package using a yarn clearer. For this purpose, the yarn diameter and the yarn length of the package are to be determined. The package weight can then be determined from the yarn diameter, the yarn length, and the density. The yarn clearer continuously scans the yarn diameter to detect defects. However, continuous measurement of the yarn diameter should not be necessary for weight measurement. Data for weight determination should only be recorded temporarily.

[0011] Even with the use of capacitive thread cleaners, which detect and eliminate undesirable mass deviations, determining the weight of the package based solely on the yarn count and yarn production length is too imprecise. As is well known, when using such capacitive thread cleaners, the operator of the package winder first defines a so-called tolerance band, i.e., a range within which yarn mass deviations are tolerated. Over the yarn production length, the sum of the yarn mass deviations occurring within this defined tolerance band can balance out, but can also tend to develop positively or negatively within the tolerance band, with the result that both positive and negative developments cause greater dispersion in package weights.

[0012] As indicated above, the known devices and methods for producing cross-wound bobbins with the same thread length or diameter have proven themselves in practice. However, to date, no devices or methods are known that enable the precise determination of the weight of a cross-wound bobbin during the winding process. Accordingly, the known devices and methods do not allow for precise statements about the instantaneous machine productivity of a textile machine producing cross-wound bobbins, which is increasingly desired by operators of textile machines producing cross-wound bobbins, especially automatic cross-wound bobbins.

[0013] Based on the aforementioned prior art, the object of the invention is to develop a method and a textile machine which makes it possible to make an exact determination of the weight of the individual cross-wound bobbins during the winding of cross-wound bobbins on the workstations of textile machines producing cross-wound bobbins.

[0014] This object is achieved according to the invention in that the thread clearer successively, i.e., continuously, scans the yarn mass of a running thread to determine the weight of the package, and yarn mass values ​​are determined. To determine the weight of the package, values ​​are determined from the yarn scans of the thread clearer, which are then summed over the yarn production length of the package. The running thread is thus completely scanned. All scans or values ​​resulting from the complete scanning of the yarn production length are thus included in the total.

[0015] Advantageous embodiments of the invention are the subject of the subclaims.

[0016] The method according to the invention has the advantage that it ensures the production of cross-wound bobbins whose weight is always precisely known in a relatively simple manner, i.e., without the use of additional, new, cost-intensive hardware. By knowing the exact weight of the finished cross-wound bobbins, the operator of a textile machine producing cross-wound bobbins has precise insight into the machine productivity of the respective textile machine producing cross-wound bobbins. Using the method according to the invention, the weight can be determined with the accuracy of a scale. Subsequent weighing is thus eliminated.

[0017] Weight deviations between bobbins of the same length are generally undesirable. Therefore, according to a further development of the invention, it is proposed that the successively determined weight of the package is monitored for deviations from an expected value and that, in the event of an undesirable deviation in the determined weight of the package, the weight deviation is counteracted during the winding process. The expected value can be determined from the weights and the weight increase over the bobbin travel of the previously wound packages of the same batch. To influence the weight of the package, for example, a minimum length can be specified and any additional thread length can be made dependent on the weight already achieved. If the textile machine producing the packages is a spinning machine, it would also be conceivable to adjust the spinning parameters in order to counteract a weight deviation.

[0018] In principle, the method could be carried out with any thread cleaner that detects diameter variations. This means that it would be possible to use both an optical and a capacitive thread cleaner. However, a capacitive thread cleaner can determine the weight of the package much more accurately, as it directly detects the mass of the yarn fibers in the yarn cross-section. The sampled values ​​are proportional to the yarn weight. This provides direct yarn mass values. With an optical sensor, the yarn mass values ​​can only be estimated indirectly from the diameter values. To achieve the desired accuracy, it is therefore proposed to use exclusively capacitive thread cleaners for the method according to the invention.

[0019] The thread clearer thus provides yarn mass values ​​per production length. To determine the weight of the package, the yarn mass values ​​can be summed or integrated over the production length of the package. However, thread clearers often only measure changes. Therefore, the package weight is preferably determined from deviations in yarn mass values.

[0020] Preferably, at the start of the batch, an average yarn mass is calculated from several yarn mass values. During the entire bobbin travel, all relative deviations of individual yarn samples from this average yarn mass, based on the yarn production length, are summed. This means that a yarn mass integral is formed, which, if not equal to 0, is used to generate a correction factor. The correction factor is used to approximate the weight of the package produced at the work station to a production weight of the package calculated from the yarn count or the average yarn mass and the yarn production length. The determined production weight of the package is therefore calculated from the yarn count or the average yarn mass, the production length, and the correction factor. The calculations and evaluations can be carried out using a computing device on the textile machine.

[0021] In an advantageous embodiment, it is also provided that the length of all yarn defects that are eliminated due to impermissible deviations from the yarn mass mean are buffered, and the buffered length of the yarn defects is used to correct the yarn mass integral. This ensures that, when calculating the correction factor, only yarn samples that lie within a permissible fluctuation range with regard to the yarn mass mean are taken into account, but that yarn samples that were eliminated as yarn defects during the bobbin travel are not taken into account when calculating the correction factor.

[0022] Furthermore, an advantageous embodiment provides for the value of the yarn mass integral to be adjusted if the average yarn mass changes during production. This means that if it turns out during a bobbin run that the originally determined average yarn mass has changed, for example, because the yarn number of the supply bobbins has changed slightly, the value of the yarn mass integral is also adjusted accordingly.

[0023] As is well known in the context of capacitive thread cleaners, the yarn mass value is determined based on the mass of the yarn fibers in the yarn cross-section, as well as the finishing agents and the moisture content of the yarn. This means that the yarn mass value also takes into account the moisture content of the yarn mass and all other substances adhering to the yarn mass.

[0024] The invention also relates to a textile machine producing cross-wound bobbins for carrying out the method according to the invention, comprising a computing device and a plurality of workstations, each of which has a winding device for laying a thread on the cross-wound bobbin and a capacitive thread cleaner arranged in the region of the thread path, which removes undesirable mass deviations of the thread during the winding process. According to the invention, the thread cleaner is designed to successively scan the yarn mass of a running thread and to forward the determined yarn mass values ​​to the computing device. The computing device is designed to determine the weight of the cross-wound bobbin from the yarn scans of the thread cleaner, which are then summed over the yarn production length of the cross-wound bobbin.

[0025] In the textile machine according to the invention, the central control unit of the cross-wound bobbin-producing textile machine, for example, is used as the computing device. However, the workstation computers of the workstations of the cross-wound bobbin-producing textile machine can also be used as computing devices. This means that both the central control unit of the textile machine and the workstation computers of the workstations of the textile machine can be modified relatively easily in terms of software so that they reliably perform all necessary calculations when needed.

[0026] Further details of the invention can be found in an embodiment explained below with reference to the drawing.

[0027] It shows: Fig. 1 in side view a work station of a cross-winding machine at which the method according to the invention is used.

[0028] As is known, automatic cross-winding machines 1 have a plurality of similar work stations 2, in this case winding stations, between their (not shown) end frames. At these work stations 2, as is also known and therefore not explained in detail, spinning bobbins 3, which were produced on a ring spinning machine upstream in the production process and which contain relatively little yarn material, are rewound into large-volume cross-wound bobbins 5. After their completion, these bobbins are transferred by means of an automatically operating (not shown) service unit, preferably by means of a so-called cross-wound bobbin changer, to a machine-length cross-wound bobbin transport device 7 and transported from there to a bobbin loading station or the like arranged at the end of the machine.Such automatic cross-winders 1 also often have a logistics device in the form of a bobbin and tube transport system 6, in which the spinning bobbins 3 or the unwound empty tubes circulate on transport plates 11. Such a bobbin and tube transport system 6 is described in . Figure 1 Only the bobbin feed section 24, the reversibly driven storage section 25, one of the transverse transport sections 26 leading to the work stations 2, and the tube return section 27 are shown. The spinning bobbins 3 delivered via the bobbin and tube transport system 6 are positioned in an unwinding position 15, which is located in the area of ​​the transverse transport sections 26 at the work stations 2, and rewound into large-volume cross-wound bobbins 5.

[0029] The individual workstations 2 of the cross-winding machine 1 are equipped with various devices that ensure proper winding operation of the workstations 2. One of these devices is, for example, the winding device 4, which, as usual, has a bobbin frame 8 mounted for limited movement around a pivot axis 12, in which the cross-wound bobbin 5 is rotatably mounted. Figure 1 In the embodiment shown, the cross-wound bobbin 5 also rests with its surface on a bobbin drive roller 9 driven by an electric motor during the winding operation, which rotates the cross-wound bobbin 5 with frictional engagement during the winding operation.

[0030] In the area of ​​the winding device 4, a thread traversing device 10 is also installed, which ensures that the thread 16 is wound onto the cheese 5 in intersecting layers during the winding process. In the exemplary embodiment, the thread traversing device 10 has a finger thread guide 13, which is connected to an electromechanical drive 14 and which continuously traverses the thread 16 between the end faces of the cheese 5 during the winding process. The drive 14 of the thread traversing device 10, like the electric motor of the bobbin drive roller 9, is connected via control lines to a workstation computer 28 of workstation 2, which in turn is connected via a bus connection 29 to the central control unit 30 of the automatic cheese winder 1.

[0031] The individual workstations 2 are each further equipped with a suction nozzle 17 and a gripper tube 18 and have various additional thread monitoring or thread handling devices, which are also connected to the workstation computer 28 via corresponding control lines. Such workstations 2 each have, for example, a pneumatic splicing device 19, with which the thread end of the upper thread can be spliced ​​to the thread end of the lower thread if necessary, for example, after a thread break.

[0032] The work stations 2 also each have a bobbin thread sensor 32, a thread tensioner 20, a capacitive thread cleaner 21, a waxing device 22, a thread cutting device 23, a thread tension sensor 31, and a measuring device 33 that determines the length of the running thread 16. The measuring device 33 is, for example, a device as described in DE 42 25 842 A1, i.e., a measuring device 33 in which the thread speed is determined with the aid of a runtime correlator, which is then directly evaluated by an integrator to determine the cumulative running length of the thread 16 wound into a cross-wound bobbin 5 at the work station 2. However, instead of using such a highly precise measuring device 33, the thread production length can also be determined in another way.The yarn production length can also be determined, for example, via the number of revolutions of the bobbin drive roller 9, assuming a specific yarn production length per roller revolution. However, due to production-related conditions such as slippage and yarn tension fluctuations, the values ​​determined using this known method are not always entirely accurate. Function of the inventive method:

[0033] Before starting the winding operation, for example after a batch change, the individual work stations 2 of a cross-winding machine 1 are first supplied with fresh pay-off bobbins, preferably with spinning cops 3 of the new yarn batch manufactured on ring spinning machines.

[0034] This means that at least one spinning cop 3 is first fed into each work station 2 of the automatic cross-winder 1 via the bobbin and tube transport system 6 and positioned in an unwinding position 15 in the area of ​​the transverse transport sections 26 of the work stations 2. The thread end, which is available, for example, at the tube tip of the spinning cop 3, is then blown upwards by a thread end release device (not shown) arranged in the area of ​​the unwinding position 15 of the work station 2 and, with the aid of the gripper tube 18 and the suction nozzle 17, is either fixed directly to a cross-wound bobbin tube rotatably mounted in the bobbin frame 8 or is transported into the working area of ​​the thread take-over device of a cross-wound bobbin changer.

[0035] In such a case, the thread take-over device of the cross-wound bobbin changer positions the thread 16 in the area of ​​the bobbin frame 8 of work station 2 such that, when the bobbin frame 8 is closed, the thread 16 is clamped between the foot of a cross-wound bobbin tube, which the cross-wound bobbin changer has previously loaded into the bobbin frame 8, and one of the tube receiving plates of the bobbin frame 8. The thread 16 of the spinning cop 3 of the new yarn batch is thus fixed to the new cross-wound bobbin tube, so that a new winding process can be started at the relevant work station 2.

[0036] According to the method of the invention, at the beginning of the batch start, the capacitive thread clearer 21 successively determines numerous yarn mass values ​​of the passing thread 16 drawn off from the spinning cop 3 and transmits these yarn mass values ​​to a computing device, for example, the workstation computer 28 of the relevant workstation 2 or the central control unit 30 of the automatic cross-winder 1. The computing device 28 or 30 then calculates the average yarn mass from these yarn mass values. When determining the yarn mass values, which are each proportional to the yarn weight per production length, the capacitive thread clearer 21 takes into account not only the mass of the yarn fibers in the yarn cross-section, but also the finishing agents adhering to the fibers and the moisture content of the yarn.

[0037] In addition, in the computing device 28 or 30, all relative deviations of individual yarn samples from the average yarn mass value are summed during the entire bobbin travel, i.e., during the entire production length of the yarn, and a yarn mass integral is calculated from this. This means that the yarn mass integral is equal to 0 if, viewed over the entire production life of the bobbin, the sum of the positive and negative yarn mass deviations is equal. However, if the sum of the positive and negative yarn mass deviations is unequal, this results in a correction factor for the produced yarn weight. This means that using the correction factor, the production weight calculated in the computing device 28 or 30 and the yarn weight of the package 5 actually produced at the respective workstation 2 of the package winder 1 can be approximated relatively precisely.In this way, the operator of the cross-winding machine 1 can be enabled to have an overview of the exact production volume of the textile machine when manufacturing a specific batch of yarn.

[0038] As explained above, the removed yarn defect lengths are taken into account when determining the yarn mass integral. This means that when creating an exact yarn mass integral, the lengths of all thread defects that were removed due to unacceptable deviations from the average yarn mass are buffered and used to correct the yarn mass integral. The value of the yarn mass integral is also adjusted if the average yarn mass changes during a bobbin run. List of reference symbols 1 Cross-winding machine 17 suction nozzle 2 workplace 18 gripper tube 3 Spinheads 19 Splicing device 4 winding device 20 Thread tensioner 5 cross-wound bobbin 21 Thread cleaner 6 Coil and 22 Paraffining facility Tube transport system 23 Thread cutting device 7 Cross-wound bobbin transport device 24 Cops feed line 8 spool frame 25 Storage section 9 spool drive roller 26 Cross transport route 10 Thread traversing device 27 Sleeve return line 11 Transport plate 28 Workplace calculator 12 Swivel axis 29 Bus connection 13 Finger thread guide 30 Central control unit 14 drive 31 Thread tension sensor 15 Unwinding position 32 bobbin thread sensor 16 thread 33 measuring device

Claims

1. A method for determining the weight of a cross-wound package (5) produced on a textile machine (1) comprising a plurality of workstations (2), each workstation (2) having a winding device (4) for placing a thread (16) on the cross-wound package (5) as well as a capacitive thread clearer (21) that is arranged in the area of the thread path and clears unwanted mass deviations of the thread (16) during the winding process, characterised in that the thread clearer (21) successively, that is continuously, scans the yarn mass of a running thread (16) completely and yarn mass values are determined, for the purpose of determining the weight of the cross-wound package (5), values are determined from all yarn scans of the thread clearer (21), said values being added together over the yarn production length of the cross-wound package (5).

2. The method according to claim 1, characterised in that a yarn mass mean value is calculated from several yarn mass values at the start of the lot, the deviations of the individual yarn scans from this yarn mass mean value are determined during the entire package journey, the deviations are added together relative to the yarn production length, and the weight of the cross-wound package (5) is calculated from the yarn count of the thread (16), the yarn production length and the sum of the deviations.

3. The method according to claim 2, characterised in that a correction factor is determined from the sum of the deviations and that the weight of the cross-wound package (5) is calculated from the yarn count of the thread (16), the yarn production length and the correction factor.

4. The method according to one of claims 2 or 3, characterised in that the length of all thread defects cleared due to impermissible deviations from the yarn mass mean value is buffered and taken into account to correct the sum of the deviations.

5. The method according to one of claims 2 to 4, characterised in that the sum of the deviations is adjusted if the yarn mass mean value changes during production.

6. The method according to any one of the preceding claims, characterised in that the mass of the yarn fibres in the yarn cross-section, the finishing agents and the moisture content of the yarn are taken into account when determining the yarn mass value.

7. A textile machine (1) that produces cross-wound packages for implementing the method according to one of claims 1 to 6, said textile machine being equipped with a computing device (28, 30) and a plurality of workstations (2), each workstation (2) having a winding device (4) for placing a thread (16) on the cross-wound package (5) as well as a capacitive thread clearer (21) that is arranged in the area of the thread path and clears unwanted mass deviations of the thread (16) during the winding process, characterised in that the thread clearer (21) is designed to successively, that is continuously, scan the yarn mass of a running thread (16) completely and forward the determined yarn mass values to the computing device (28, 30), and the computing device (28, 30) is designed to determine values from all yarn scans of the thread clearer (21), said values being added together over the yarn production length of the cross-wound package (5) for the purpose of determining the weight of the cross-wound package (5).

8. The textile machine (1) that produces cross-wound packages according to claim 7, characterised in that the computing device that processes the values determined by the capacitive thread clearer (21) is the central control unit (30) of the textile machine (1).

9. The textile machine that produces cross-wound packages according to claim 7, characterised in that the computing device that processes the values determined by the capacitive thread clearer (21) is the workstation computer (28) of the relevant workstation (2) of the textile machine (1).

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