EP3984934A1 - Method for operating a spinning machine and spinning machine - Google Patents

Abstract

The invention relates to a method for operating a spinning machine (1) which is equipped with a large number of work stations (2), each of which has an open-end spinning device (3) for producing a thread (7), a thread take-off device for taking off the thread from the Spinning device and a winding device (4) for winding a cross-wound bobbin (8), the winding device (4) having a pivotably mounted bobbin frame (9) for holding a bobbin tube (10) and a drivable bobbin drive drum (11) for rotating the bobbin tube ( 10) or the cross-wound bobbin (8) and the thread take-off device (14) has a drivable take-off roller (40) and the work station (2) has at least one individual drive (23, 39) which drives the bobbin drive drum (11) or drives the take-off roller (40). The invention also relates to the spinning machine. In order to minimize the effort required in connection with the creation of a proper thread reserve (33) in spinning machines (1) designed in this way, the invention provides that the individual drive (23, 39) during the Creation of a thread reserve (33), in which the thread (7) is wound onto the bobbin sleeve (10) in parallel windings (34), is controlled in such a way that it is ensured that the thread winding speed (V₁ ) and the take-off speed (V_F) are matched to one another in such a way that the resulting thread tension enables the thread reserve (33) to be securely fixed on the bobbin tube (10).

Description

The invention relates to a method for operating a spinning machine, in particular an open-end rotor spinning machine, which is equipped with a large number of work stations, each of which has a spinning device, in particular an open-end rotor spinning device, for producing a thread, a thread withdrawal device for withdrawing the thread from the spinning device and have a winding device for winding a cross-wound bobbin, the winding device having a pivotably mounted bobbin frame for holding a bobbin tube and a drivable bobbin drive drum for rotating the bobbin tube or the cross-wound bobbin, the thread take-off device having a drivable take-off roller and the work station having at least one Single drive has that drives the spool drive drum or the take-off roller.

In connection with open-end rotor spinning machines, it has long been known and, for example, in DE 198 36 065 A1 shown and described that such textile machines usually have a large number of similar jobs arranged next to one another in a row, on which a z. B. in a sliver can is spun into a thread which is then wound up to form a cross-wound bobbin.

The work stations of such open-end rotor spinning machines always have a plurality of different work elements, for example a spinning device and a winding device. However, the known open-end rotor spinning machines sometimes differ considerably from one another, in particular with regard to the drives of their working elements.

through the DE 43 34 483 C2 For example, open-end rotor spinning machines are known in which the various working elements of the work stations are each actuated by means of drive means that are as long as the machine. This means that in these jobs, for example, the spinning rotors and the associated opening rollers are driven by a machine-long tangential belt, which is acted upon by an electric motor arranged at the end of the machine.

Furthermore, such workstations each have a sliver draw-in cylinder, a yarn take-off device and a spool drive drum, which are also each driven by means of machine-long shafts to which an electric drive is connected at the machine end.

The disadvantage of such a design is that during the spinning/winding operation, all of the working elements of the same type always inevitably rotate at the same working speed. This means that in open-end rotor spinning machines designed in this way, for example, the rotational speed of the bobbin drive drums of all work stations is always the same and is preferably set in such a way that during the spinning/winding process, in which bobbins are created with a cross winding, as is known, the thread winding speed is reduced to the speed with which the thread pull-off devices pull the threads out of the open-end rotor spinning devices, is coordinated so that the resulting thread tension enables reliable winding of the cross-winding. For this purpose, the thread winding speed corresponds approximately to the speed of the thread pull-off device.

Furthermore, for example DE 10 2013 009 998 A1 , Open-end rotor spinning machines are known in which the various working elements of the jobs are not driven by machine-long drive means, but are each equipped with a single drive.

In these known open-end rotor spinning machines, too, the individual drives for the bobbin drive drums and the individual drives for the thread take-off devices are set in such a way that, during the winding of the cross-winding of the cross-wound bobbin, the thread winding speed is coordinated with the take-off speed of the thread from the open-end rotor spinning device specified by the thread take-off device in order to to guarantee sufficient thread tension for winding the cross winding.

Furthermore, open-end rotor spinning machines are known, which are equipped with so-called self-sufficient work stations. That is, such open-end rotor spinning machines have jobs that are largely self-sufficient and z. B. after a thread breakage can automatically start spinning again.

Such, for example, in the DE 101 39 075 A1 or the DE 10 2007 023 490 A1 Work stations that are described in relatively detail have, as usual, an open-end rotor spinning device for producing a thread and a winding device for winding a cross-wound bobbin. In addition, these work stations are each equipped with a work station's own, pivoted, vacuum-loadable suction nozzle.

Even with such self-sufficient jobs, the spooling devices are each equipped with a pivoted spool frame that can be driven by a single motor Bobbin drive drum and a thread traversing device that can also be acted upon by a single motor, e.g. in the form of a thread guide. This means that each of the work stations has a winding device with a bobbin drive drum that is acted upon in a defined manner by an individual drive for rotating a bobbin tube or a cheese and a thread traversing device driven by a single motor for the defined laying of a thread running onto the cheese during the spinning/winding process.

When creating a cross-wound bobbin, the thread runs, as already indicated above, onto the cross-wound bobbin at a winding speed which theoretically corresponds approximately to the value of the take-off speed of the thread from the open-end rotor spinning device.

In practice, however, correction factors, e.g. B. for the setting / adjustment of the winding tension and the correction of the influence of the thread guide reversal points. This means that the real winding speed of the thread during the creation of the cross winding of a cheese results from the vectorial addition of the peripheral speed of the bobbin drive drum and the operating speed of the associated thread traversing device and the correction factors.

However, this known method has the disadvantage that the thread winding speed, which is dependent on the peripheral speed of the bobbin drive drum and the traversing speed of the thread traversing device, is somewhat too low during the creation of a thread reserve in which parallel windings are wound. This means that when the thread reserve is created, the thread winding speed is approximately below the value with which the thread is drawn off from the open-end rotor spinning device, with the result that appropriate measures must be taken to prevent the thread reserve that is wound up too loosely in subsequent threads transporting the cheese from the bobbin tube. Such a measure is, for example, the arrangement of a yarn brake and a yarn storage nozzle at each of the work stations or a corresponding yarn brake with a yarn storage nozzle on the service unit.

In connection with the operation of the aforementioned open-end rotor spinning machines, it is also known that such textile machines are equipped with service units. This means that open-end rotor spinning machines that are equipped with largely self-sufficient work stations are often operated by service units that are designed as so-called cleaning/changer carriages.

Such cleaning/changer carriages prevent, for example, the work stations of the textile machines from getting too dirty during the spinning/winding operation, for example due to the fiber fly, which is almost unavoidable in spinning mills. Such cleaning/changing carriages are also used in connection with changing cheeses/empty tubes. This means that such cleaning/changer trolleys are called to a work site when the cross-wound bobbin at the work site has reached a specified diameter and has to be exchanged for an empty tube.

The cleaner/changer carriages are each connected via a machine bus to the central control unit of the open-end rotor spinning machine and have, e.g. B. in the DE 10 2008 055 965 A1 described in relatively detail, about a so-called auxiliary thread supply device, which provides the auxiliary thread required for a cheese/empty tube change. Furthermore, such cleaner/changer carriages are equipped with a thread transfer device, by means of which the auxiliary thread can be transferred to the work site. This means that if a cheese/empty tube change is necessary at one of the work stations, the cleaner/changer carriage runs to the relevant work station, which has meanwhile switched off its working elements, and positions itself there. The full cheese is then ejected from the creel by appropriate handling devices and transferred to a machine-long cheese transport device. A new empty tube is then positioned between the tube plates of the creel of the job in question and an auxiliary yarn is provided by the auxiliary yarn feed device of the cleaning/changer carriage. The beginning of the thread of the auxiliary thread is transferred by the thread transfer device to the vacuum-loaded, pivotable suction nozzle of the work station, which in turn transfers the auxiliary thread to a so-called piecing element arranged in the area of the spinning device. The piecing element then prepares the thread end of the auxiliary thread for the subsequent piecing process and keeps the auxiliary thread ready for the actual piecing process.

For repiecing the job, the prepared thread end of the auxiliary thread held ready by the piecing element is then fed back into the spinning device and applied to a fiber ring circulating in the spinning rotor of the spinning device. The auxiliary thread, which is then connected to the new spinning thread via a so-called piecing, is drawn off from the spinning device via the thread take-off device of the work station and disposed of through the suction nozzle of the work station, with the disposal continuing until the piecing is detected by a sensor device . The spinning thread will then applied to the empty tube and the winding of a thread reserve on the empty tube, which is also referred to as a bobbin tube, started. That is, the bobbin drive drum of the work station, which frictionally drives the bobbin tube, rotates at a rotational speed which is matched to the withdrawal speed of the yarn from the open-end rotor spinning device.

However, since during the winding of the thread reserve, during which, as is well known, parallel windings are created, the thread take-off speed is higher than the thread winding speed at which the thread is wound onto the bobbin tube, there is an excess of thread, with the result that without special measures, e.g. the use of a thread brake in connection with a thread storage device, the created thread reserve is wound up so loosely that it can slip off during the subsequent transport of the cheese.

Proceeding from the above-mentioned state of the art, the invention is based on the object of developing a method with which the effort required in open-end rotor spinning machines in connection with the creation of a proper thread reserve is minimized. This means that the method according to the invention ensures that the thread is always wound with a thread tension during the creation of a thread reserve, which ensures that a correct thread reserve is produced.

This object is achieved according to the invention in that the individual drive of the bobbin drive drum and/or the take-off roller is controlled during the creation of a thread reserve, in which the thread is wound onto the bobbin tube in parallel windings, in such a way that it is ensured that the thread winding speed and the take-off speed , with which the thread is pulled out of the spinning device, are matched to one another in such a way that the resulting thread tension enables the thread reserve to be securely fixed on the bobbin tube.

Advantageous configurations of the invention are the subject matter of the dependent claims.

Both the spool drive drum and the take-off roller preferably have a single drive. This makes it possible to change both the peripheral speed of the bobbin drive drum and the take-off speed for tuning. Adequate thread tension is achieved when the thread winding speed roughly corresponds to the thread withdrawal speed.

Since the bobbin drive drums and/or the take-off rollers of the work stations are each acted upon by individual drives, which are connected via control lines to the control devices of the work stations, which in turn are connected to the central control unit of the spinning machine via a machine bus, it does not require a great deal of design effort to ensure that the bobbin drive drums and/or the take-off rollers always work at an optimal working speed when creating thread reserves. This means that the method according to the invention has the advantage that a software revision of the central control unit of the spinning machine or the control devices of the work stations is sufficient to ensure that when a thread reserve is created, the bobbin drive drums always work at a circumferential speed or the take-off rollers always work at a take-off speed , in which the thread is wound with a specified thread tension.

In an advantageous embodiment, it is provided that the bobbin drive drums always rotate at a peripheral speed during the creation of a thread reserve, which differs from the peripheral speed of the bobbin drive drums during the creation of the cross windings. This means that during the creation of the thread reserves, the bobbin drive drums advantageously always rotate at a peripheral speed that is greater than the peripheral speed of the bobbin drive drums during the creation of the cross windings.

Overall, the method according to the invention enables the bobbin drive drums to be set in a simple manner in such a way that an optimal thread winding speed is always used.

In a further advantageous embodiment, it is also provided that the bobbin drive drum always rotates at a peripheral speed during the creation of a thread reserve, which ensures that the winding speed at which the thread is wound onto the bobbin sleeve and the take-off speed at which the thread is removed from the spinning device is deducted, are matched to each other. This means that it is ensured that during the creation of the thread reserve there is no excess thread length which could cause a problematic thread reserve.

According to a further preferred embodiment, the individual drive drives the take-off roller and the take-off roller rotates during the creation of the thread reserve at a take-off speed that differs from the take-off speed of the take-off roller during the Creation of the cross winding differs. During the creation of a thread reserve, the take-off roller rotates at a take-off speed that is lower than the take-off speed of the take-off roller during the creation of the cross winding. By lowering the take-off speed, the reduced winding speed when winding the thread reserve can be compensated.

Advantageously, the machine operator enters the desired data for the yarn reserve, in particular the desired number of parallel reserve turns, on the control device of a cleaner/changer carriage or on the central control unit of the open-end rotor spinning machine. The control device of the workplace then calculates the duration of the increased thread winding speed from the number of turns entered, the tube diameter of the fresh bobbin tube and the thread winding speed.

In a further advantageous embodiment, the switching of the peripheral speed of the bobbin drive drum of the work station is initiated by the service unit, which is positioned at the work station in connection with a cheese/empty tube change. This means that the service unit, which is preferably designed as a cleaning/changer trolley, transmits a signal to the control device of the work station, which then controls an individual drive of the bobbin drive drum so that the bobbin drive drum rotates at the desired peripheral speed or controls an individual drive of the take-off roller so that the take-off speed is adjusted accordingly is adjusted.

The object is also achieved by a spinning machine, preferably an open-end rotor spinning machine, which has a large number of work stations, each of which has a spinning device, in particular an open-end rotor spinning device, for producing a thread, a thread withdrawal device for withdrawing the thread from the spinning device and have a winding device for winding a cross-wound bobbin. The winding device is equipped with a pivotably mounted bobbin frame for holding a bobbin tube and with a drivable bobbin drive drum for rotating a bobbin tube or the cross-wound bobbin. The thread take-off device has a drivable take-off roller. The job has at least one individual drive that drives the spool drive drum or the take-off roller.

According to the invention, the spinning machine has a control device which, by means of a corresponding signal, ensures that the at least one individual drive is controlled in such a way that the bobbin drive drum is equipped with a thread reserve during the creation of a thread reserve peripheral speed that differs from the peripheral speed at which the bobbin drive drum rotates during the creation of the cross winding, and/or that the take-off roller rotates during the creation of a thread reserve at a take-off speed that differs from the take-off speed at which the take-off roller during the Creation of the cross winding rotates, differs.

The spinning machines are preferably equipped with service units which, among other things, carry out a change of cheese/empty tubes. Each of the service units, preferably designed as a cleaner/changer carriage, has a control device which is connected to the central control unit of the open-end rotor spinning machine via a machine bus.

When changing cheeses/empty tubes, the control device of the service unit preferably uses a corresponding signal to ensure that the bobbin drive drum rotates at a peripheral speed during the creation of a thread reserve, which differs from the peripheral speed at which the bobbin drive drum rotates during the creation of the cross winding, and /or that the take-off roller rotates during the creation of a thread reserve at a take-off speed that differs from the take-off speed at which the take-off roller rotates during the creation of the cross winding.

The winding speed at which the thread is wound onto the bobbin tube or the cross-wound bobbin results from the vectorial addition of the peripheral speed of the bobbin drive drum and the traversing speed of an associated thread traversing device.

Since the winding speed at which the thread is wound onto a bobbin tube results from the vectorial addition of the peripheral speed of the bobbin drive drum and the traversing speed of an associated thread traversing device; However, the traversing speed of the thread traversing device approaches zero during the creation of a thread reserve with parallel windings, the peripheral speed of the bobbin drive drum is preferably increased during the creation of a thread reserve such that the resulting thread tension enables the thread reserve to be securely fixed on the bobbin tube.

In an alternative embodiment, however, it can also be provided that the peripheral speed of the bobbin drive drum is not increased in connection with the creation of a thread reserve, but the take-off speed at which the thread is pulled out of the spinning device is reduced somewhat.

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

Fig. 1

in Seitenansicht eine Hälfte einer Offenend-Rotorspinnmaschine, deren Arbeitsstellen als weitestgehend autarke Arbeitsstellen ausgebildet sind und an der das erfindungsgemäße Verfahren zum Einsatz kommt,

Fig. 2

die in Figur 1 dargestellte Arbeitsstelle in perspektivischer Ansicht sowie in einem größeren Maßstab,

Fig. 3

eine Spulenhülse mit einer Fadenreserve, im vorliegenden Fall einer Fadenanfangsreserve, die mittels des erfindungsgemäßen Verfahrens erstellt wurde,

Fig. 4a

eine schematische Darstellung der Geschwindigkeitsverhältnisse während der Erstellung der Kreuzwicklung,

Fig. 4b

eine schematische Darstellung der Geschwindigkeitsverhältnisse beim Erstellen der Fadenreserve gemäß einer ersten Ausführungsform der vorliegenden Erfindung,

Fig. 4c

eine schematische Darstellung der Geschwindigkeitsverhältnisse beim Erstellen der Fadenreserve gemäß einer zweiten Ausführungsform der vorliegenden Erfindung.

It shows:

1

a side view of half of an open-end rotor spinning machine, the work stations of which are designed as largely self-sufficient work stations and on which the method according to the invention is used,

2

in the figure 1 represented workplace in a perspective view and on a larger scale,

3

a bobbin tube with a thread reserve, in the present case a thread start reserve, which was created using the method according to the invention,

Figure 4a

a schematic representation of the speed ratios during the creation of the cross winding,

Figure 4b

a schematic representation of the speed ratios when creating the thread reserve according to a first embodiment of the present invention,

Figure 4c

a schematic representation of the speed ratios when creating the thread reserve according to a second embodiment of the present invention.

In figure 1 half of an open-end rotor spinning machine 1 is shown in a side view, which has a large number of largely self-sufficient work stations 2 . Such largely self-sufficient workstations 2 are, as usual, each equipped with an open-end spinning device 3 and a spooling device 4, with a sliver 6 placed in a sliver can 5 being spun into a thread 7 in the spinning device 3, which is then fed to the spooling device 4 a cheese 8 is wound up.

As shown, the winding devices 4 are each equipped for this purpose with a creel 9 for rotatably holding the bobbin tube 10 of a cross-wound bobbin 8 and with a single-motor-driven bobbin drive drum 11 for defined rotation of the bobbin tube 10 or the cross-wound bobbin 8.

Such, e.g. in the DE 101 39 075 A1 Work stations 2, which have been described relatively extensively, also each have a thread traversing device 18 driven by a single motor, a thread take-off device 14 driven by a single motor, and a swivel-mounted suction nozzle 17 belonging to the workstation.

A so-called piecing element 20 is also installed in the area of the open-end spinning device 3 . This means that such jobs 2 can fix yarn breaks that occur during the spinning/winding process automatically. Such open-end rotor spinning machines 1 generally also have a cheese transport device 12 with which the cheeses 8 finished on the winding devices 4 can be transported to a cheese transfer station (not shown) arranged at the end of the machine.

Such open-end rotor spinning machines 1 are also usually equipped with a guide rail 13 and a support rail 15, on which a service unit 16, for example a so-called cleaning/changer carriage, can be moved. The cleaner/changer trolley intervenes automatically if there is a need for action at one of the work stations 2. Such a need for action exists, for example, if a work station 2 is very dirty and needs to be cleaned, or if a full cheese 8 is to be exchanged for a new empty tube 10 at one of the work stations 2 .

Since a piecing thread is required for such a cheese/empty tube change, such cleaning/changing carriages 16 are equipped with an auxiliary thread delivery device 21 and a thread transfer device 22, which provide such an auxiliary thread and transfer it to the workplace’s own suction nozzle 17 of workplace 2. Such cleaner/changer carriages 16 are also equipped with a control device 35, which is connected via a machine bus 36 to the central control unit 37 of the open-end rotor spinning machine 1, which in turn is connected via a machine bus 38 to the control devices 31 of the numerous work stations 2.

the figure 2 shows in perspective and on a larger scale one of the figure 1 schematically indicated, largely self-sufficient work station 2 of an open-end rotor spinning machine 1. Such jobs 2 have, as can be seen and above based on the figure 1 already indicated, via an open-end spinning device 3 and via a winding device 4. In these self-sufficient work stations 2, a piecing element 20 is arranged in the area of the so-called thread draw-off tube 19 of the open-end spinning device 3 8 retrieved thread 7 and prepares the thread end for piecing again or, in the case of a cheese/empty tube change, processes an auxiliary thread provided by the auxiliary thread delivery device 21 of a clearer/changer carriage 16 and transferred by a thread transfer device 22 of the clearer/changer carriage 16.

Such work stations 2 also each have a thread take-off device 14, which both ensures that the prepared spun thread 7 is fed back into the open-end spinning device 3 when it is piecing again, and also ensures that the thread 7 is drawn off during regular spinning at a predetermined thread take-off speed V _F is withdrawn from the open-end spinning device 3. For this purpose, the thread take-off device 14 has a take-off roller 40 which is driven by an individual drive 39 . The thread 7 is pressed against the draw-off roller 40 by means of a pressure roller.

As can also be seen, the spooling device 4 has a pivotably mounted spool frame 9 for rotatably holding an empty tube 10 . This empty tube, which is also referred to as a bobbin tube 10, is part of a cross-wound bobbin 8, which is rotated by means of a spool drive drum 11 by friction. In addition to a winding drive drum 11 that can be acted upon by an individual drive 23, the winding device 4 also has a yarn traversing device 18 that is driven, for example, by means of a stepping motor 24.

Furthermore, such, largely self-sufficient work stations 2 each have a pivoted suction nozzle 17, which z. B. defined by a stepping motor 25 between a lying in the region of the winding device 4 thread take-up position and a lying in the region of the spinning device 3 thread transfer position is adjustable. The individual drives 23, 24, 25 and 39 are each connected via a control line 32 to a control device 31 of the workstations 2 and can be controlled in a defined manner by the latter.

Advantageously, each of the work stations 2 also has a thread monitor 26, a paraffining device 27 and a stationary thread storage nozzle 28 which can be subjected to a defined negative pressure and which, in particular, during the run-up of the work station 2 to the use comes. This means that the excess length of thread that occurs during the run-up of a work station 2 is temporarily stored by the thread storage nozzle 28 .

How out figure 2 As can further be seen, both the stationary yarn storage nozzle 28 and the pivotably mounted suction nozzle 17 are connected to a machine-specific vacuum network 29 , the vacuum source of which is identified by the reference number 30 .

the figure 3 shows a bobbin tube 10 that was exchanged from a cleaning/changing carriage 16 into the bobbin frame 9 of a work station 2 during the course of a cheese/empty bobbin change, while a thread reserve 33 was being created. The bobbin tube 10 held between the pivoted arms of a bobbin frame 9 is located on a bobbin drive drum 11 which rotates the bobbin sleeve 10 by friction. That is, the bobbin drive drum 11 is rotated by a single drive 23, which is connected via a control line 32 to the control unit 31 of the work station 2, at a peripheral speed V _2B' which is higher than the peripheral speed V _2A at which the bobbin drive drum 11 is rotated during the Creation of a cross winding rotated. The winding speed V ₁ of the thread 7 onto the bobbin tube 10 corresponds approximately to the take-off speed V _{FB ′} at which the thread 7 is taken off from the open-end spinning device 3 .

In connection with the creation of a thread reserve 33, it is also possible, instead of increasing the peripheral speed V ₂ of the bobbin drive drum 11, to increase the take-off speed V _FB during the creation of the thread reserve 33 compared to the take-off speed V _FA during the creation of the cross-winding by appropriate control of the individual drive 39 to lower something.

Since at this point in time the thread traversing device 18 is also out of operation or positioned in such a way that the thread 7 that is running up is not affected, a thread reserve 33 is created, which has a number of parallel windings 34 .

Function of the method according to the invention:

At the beginning of the commissioning of an open-end rotor spinning machine 1, i.e. before the start of the spinning/winding process, a machine operator provides the desired data for the thread reserves on the control device 35 of the cleaner/changer carriage 16 or on the central control unit 37 of the open-end rotor spinning machine 1 33 of the cheeses to be created 8 and starts the textile machine.

During the "normal" spinning/winding operation, as in Figure 4a shown schematically, the thread 7 produced in the spinning device 3 is drawn off from the open-end spinning device 3 by the thread draw-off device 14 at a thread draw-off speed V _FA and wound up on the winding device 4 to form a cross-wound bobbin 8 . This means that the cross-wound bobbin 8, which is held freely rotatably in the bobbin frame 9 via its bobbin tube 10, is rotated by the bobbin drive drum 11, which rotates at a peripheral speed V _2A , in the winding direction by friction. At the same time, the thread 7 is laid, for example by the thread guide of a thread traversing device 18, in such a way that the thread 7 runs onto the lateral surface of the cross-wound bobbin 8 in intersecting layers. The incoming yarn 7 is traversed by the yarn traversing device 18 at a speed V ₃ that can be predetermined. From the vectorial addition of the peripheral speed V ₂ of the bobbin drive drum 11 and the traversing speed V ₃ of the thread traversing device 18, a thread winding speed Vi results, which corresponds approximately to the thread withdrawal speed V _F . The yarn withdrawal speed V _F is the speed at which the yarn 7 produced in the open-end spinning device 3 is withdrawn from the open-end spinning device 3 .

When the cross-wound bobbin 8 has reached a predetermined diameter or a predetermined thread length, which z. B. is detected by sensors, a cheese / empty tube change is initiated. This means that the central control unit 37 of the open-end rotor spinning machine 1 requests a service unit 16, preferably a so-called cleaner/changer carriage. The cleaner/changer carriage 16 travels to the relevant work station 2, positions itself there and first transfers the full cheese 8 from the work station 2 from the creel 9 to a machine-long cheese transport device 12. The cleaner/changer carriage 16 then changes a fresh bobbin tube 10 in the creel 9 of the job 2 a. The cleaning/changing carriage 16 equipped with an auxiliary yarn delivery device 21 also provides an auxiliary yarn which is transferred by means of a yarn transfer device 22 into the area of the open-end rotor spinning device 3 of the relevant work station 2 . This auxiliary thread is such. B. in the DE 10 2008 055 965 A1 described in detail, required for re-piecing the job 2 and later, that is, before the new thread 7 is wound onto the bobbin tube 10, cut out again.

The thread 7 freshly produced in the open-end spinning device 3 is wound onto the bobbin sleeve 10, with a thread reserve 33 being created on the bobbin sleeve 10, in the present case a so-called initial thread reserve. That is, the thread 7 will be in parallel turns 34 wound on an end portion of the bobbin tube 10, which is thereby driven by the spool drive drum 11 frictionally. The speed ratios during winding of the thread reserve are shown schematically in Figure 4c shown. The bobbin drive drum 11 is rotated at a peripheral speed V _{2B '} , which is above the peripheral speed V _2A , at which the bobbin drive drum 11 rotates during the creation of the cross winding. This means that the peripheral speed V _{2B '} of the bobbin drive drum 11 compensates for the lack of influence of a traversing thread guide when winding parallel windings 34 and a thread winding speed V ₁ is realized on the bobbin sleeve 10, which approximately corresponds to the thread withdrawal speed V _{FB '} , with the result that the thread reserve 33 is wound onto the bobbin tube 10 with a proper thread tension.

Alternatively, when the thread reserve 33 is created, the take-off roller 40 is rotated at a thread take-off speed V _FB that is below the thread take-off speed V _FA at which the take-off roller 40 rotates while the cross-winding is being created. Reducing the yarn take-off speed V _F of the take-off roller 40 has the same effect as increasing the peripheral speed V ₂ of the bobbin drive drum 11. The speed ratios are in Figure 4b shown.

Of course, a mixed solution is also conceivable, in which both the peripheral speed V ₂ of the bobbin drive drum 11 is increased and the thread take-off speed V _F is reduced. It is only important that the result is that the thread winding speed V ₁ corresponds approximately to the thread draw-off device V _F so that there is a thread tension that meets the needs. <b>Reference List</b> 1 Open-end rotor spinning machine 30 vacuum source 2 place of work 31 control device 3 open-end spinning device 32 control line 4 spooling device 33 thread reserve 5 sliver can 34 parallel turns 6 sliver 35 control device 7 thread 36 machine bus 8th cone 37 central control unit 9 bobbin frame 38 machine bus 10 bobbin case 39 single drive 11 spool drive drum 40 pull-off roller 12 Cheese transport device 13 guide rail 14 thread take-off device _v1 thread winding speed 15 support rail _v2 peripheral speed 16 service unit V _2A peripheral speed during 17 suction nozzle the creation of the cross winding 18 thread traversing device _V2B / _V2B' peripheral speed during 19 thread withdrawal tube the creation of the thread reserve 20 piecing organ _v3 traverse speed 21 Auxiliary thread feeding device _VF yarn take-off speed 22 thread transfer device V _FA yarn take-off speed 23 single drive while creating the 24 single drive cross wrap 25 single drive V _FB /V _FB' yarn take-off speed 26 thread monitor while creating the 27 paraffining device thread reserve 28 thread storage nozzle 29 negative pressure network

Claims (11)

Method for operating a spinning machine (1) which is equipped with a large number of work stations (2), each of which has a spinning device (3) for producing a thread (7), a thread withdrawal device (14) for withdrawing the thread from the spinning device (3 ) and a winding device (4) for winding a cross-wound bobbin (8), the winding device (4) having a pivotably mounted bobbin frame (9) for holding a bobbin tube (10) and a drivable bobbin drive drum (11) for rotating the bobbin tube ( 10) or the cross-wound bobbin (8), the thread take-off device (14) having a drivable take-off roller (40) and the work station (2) having at least one individual drive (23, 39) which drives the bobbin drive drum (11) or drives the take-off roller (40),
characterized,
that the individual drive (23, 39) is controlled during the creation of a thread reserve (33), in which the thread (7) is wound onto the bobbin sleeve (10) in parallel windings (34), so that it is ensured that the winding speed (V ₁ ), with which the thread (7) is wound onto the bobbin sleeve (10), and the take-off speed (V _F ), with which the thread (7) is pulled off by the thread take-off device (14), are matched to one another in such a way that that the resulting thread tension enables the thread reserve (33) to be securely fixed on the bobbin tube (10). Method according to Claim 1, characterized in that the individual drive (23) drives the bobbin drive drum (11) and that the bobbin drive drum (11) rotates at a peripheral speed (V _2B , V _2B' ) during the creation of the thread reserve (33) which differs from the peripheral speed (V _2A ) of the bobbin drive drum (11) during the creation of the cross winding. Method according to Claim 2, characterized in that the bobbin drive drum (11) rotates at a peripheral speed (V _2B , V _2B' ) during the creation of a thread reserve (33) which is greater than the peripheral speed (V _2A ) of the bobbin drive drum (11) during the creation of the cross wrap. Method according to Claim 1, characterized in that the individual drive (39) drives the take-off roller (40) and that the take-off roller (40) rotates at a take-off speed (V _FB , V _FB' ) while the thread reserve (33) is being created of the Take-off speed (V _FA ) of the take-off roller (40) during the creation of the cross winding is different. Method according to Claim 4, characterized in that the take-off roller (40) rotates during the creation of a thread reserve (33) at a take-off speed (V _FB , V _FB' ) which is lower than the take-off speed (V _FA ) of the take-off roller (40) during the creation of the cross wrap. Method according to one of the preceding claims, characterized in that during the creation of a thread reserve (33), the bobbin drive drum (11) rotates at a peripheral speed (V _2B , V _2B' ) and the take-off roller (40) rotates at a take-off speed (V _FB ), which are matched to one another with the aid of the at least one individual drive (23, 39). Method according to one of the preceding claims, characterized in that the machine operator enters the desired data for the thread reserve (33) on the control device (35) of a service unit, in particular a cleaner/changer carriage (16). Method according to one of the preceding claims, characterized in that the machine operator enters the desired data for the thread reserve (33) on the central control unit (37) of the open-end rotor spinning machine (1). Method according to one of the preceding claims, characterized in that the switching of the peripheral speed (V ₂ ) of the bobbin drive drum (11) and/or the take-off speed (V _F ) of the take-off roller (40) of a work station (2) during a cheese/empty tube change a service unit (16) is initiated, which is positioned at the work site (2) at this time. Spinning machine (1), which has a large number of work stations (2), each of which has a spinning device (3) for producing a thread (7), a thread withdrawal device (14) for withdrawing the thread from the spinning device (3) and a winding device (4) for winding a cross-wound bobbin (8), the winding devices (4) each having a pivotably mounted bobbin frame (9) for holding a bobbin tube (10) and a drivable bobbin drive drum (11) for rotating a bobbin tube (10) or The cheese (8) are equipped, and wherein the thread take-off device (14) has a drivable take-off roller (40) and the work station (2) has at least one individual drive (23, 39) which drives the bobbin drive drum (11) or the take-off roller (40),
characterized,
that the spinning machine has a control device (35) which uses a corresponding signal to ensure that the at least one individual drive is controlled in such a way that the bobbin drive drum (11) rotates at a circumferential speed (V _2B , V _{2B '} ) rotates, which differs from the peripheral speed (V _2A ) at which the bobbin drive drum (11) rotates during the creation of the cross winding, and/or that the take-off roller (40) during the creation of a thread reserve (33) at a take-off speed (V _FB , V _FB' ) rotates, which differs from the take-off speed (V _FA ) at which the take-off roller (40) rotates during the creation of the cross winding. Spinning machine (1) according to Claim 10, characterized in that the work stations (2) are supplied by a service unit (16) which, if necessary, changes cheeses/empty tubes, and in that the service unit (16) comprises the control device (35) which is a machine bus (36, 38) is connected to a central control unit (37) of the open-end rotor spinning machine (1) and control devices (31) of the work stations (2).

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