EP1162295B1 - Method for operating a creel and creel for a winding machine - Google Patents

Description

The invention relates to a method for operating a creel for a winding system according to the preamble of claim 1. With such a method as optimal as possible tension compensation of all threads on a creel is sought, because the different lengths of the threads between winding units and winding machine and the associated thread guide without appropriate compensation would lead to different thread tensions. The consequence of this would be an uneven winding density.

By the EP-A 319 477 a device for tension compensation of the threads has become known on a creel in which a common control rod, the thread brakes of the vertical rows of winding units are acted upon different amounts. The control rod is activated via drive motors which receive actuating signals from a processor. In this case, the actual value of the thread tension of a whole thread bandage is measured by means of a measuring roller shortly before winding. A consideration of the thread tension of individual threads or individual groups of threads is not possible.

The DE-A 195 46 473 discloses a method of controlling winder winders. Again, there is a voltage measurement of the thread assembly just before winding to act by means not shown in detail on the tension of the threads on the creel. However, with the aid of a measuring carriage which can be moved transversely across the thread bandage, the successive measuring of the tension of individual threads in a predetermined time interval is possible. From this, a mean voltage value is formed, which is carried out according to the common tensioning of all threads. With this method, an individual control of individual threads can not be realized because not every thread can be scanned simultaneously. Other disadvantages of this method are that the interval measurement at the winding speeds traveled today is too slow and also in each case the measured thread is mechanically acted upon by the measuring means, which causes an individual thread tension change.

The DE-A 44 18 729 also relates to a device for regulating the thread tension in a creel. This device has a brake rotor for each bobbin holder directly at the winding unit. As a sensor for the thread tension is a clamping lever, which is acted upon by the unwound thread. At each bobbin holder, a fluid pressure working load device engages the cocking lever, wherein the fluid pressure is commonly adjustable for all the load devices. The individual control of the thread tension can thus be superimposed by a general adjustment of all thread tensioner. A disadvantage of this device, however, is that the control loop is limited directly to the winding unit. This arrangement is not suitable for a creel with overhead deduction. The deceleration directly on the bobbin holder is also not suitable for all work processes and the different run length of the threads between winding unit and winding machine is not taken into account.

Finally, the reveals DE-U-296 08 169 a winding device for threads of reel gates, in which a measuring device for determining yarn tension in threads is arranged, wherein the central adjustment of the winding units associated Vorumschlingungsstangen is controlled according to the measurement result. The measuring device consists of individual pressure measuring strips, the each support a variety of threads. Thus, a monitoring of the tension in the monofilament is also not possible, apart from the fact that the pressure gauges can act on only the outermost threads of a thread assembly.

From the US 5,454,151 a creel with a plurality of coils has become known, the threads are withdrawn by means of a warping drum. Each thread runs through a device for adjusting the tension of a thread. The thread passes in relation to the thread running direction successively a unit for receiving the thread tension and a driven drum of a brake unit whose effective peripheral speed is changeable in the same direction to the recorded thread tension. The two components are mounted on a common carrier. The drum of the brake unit is driven by a constant speed motor. The thread tension receiving unit includes a thread follower which shifts along with the thread. A change in the position of the thread catcher directly and directly affects the brake unit.

The EP-0 012 235 shows an arrangement with a creel and a warper, wherein a roller brake is used for each thread. All horizontal coils of the gate are connected to each other via a common control rod, so that the roller brakes can be adjusted simultaneously. The adjusting rods are in turn connected to each other via a lever mechanism which can be activated as a whole via a motor of a brake adjusting device. The assembly further includes a thread tension measuring device that measures the thread tension of a single, selected thread. With a control device, the actual values determined with the yarn tension measuring device are compared with preset desired values, in the presence of a target value-actual value difference, the motor of a brake adjusting device is applied.

However, it would also be quite generally desirable to use a creel with various types of filaments, e.g. different yarn qualities, yarn counts or thread colors, to adapt the thread tension in each case to the individual thread types. Such individual consideration of Garngattungen was previously not possible.

It is therefore an object of the invention to provide a method of the type mentioned above, which allows simple means an optimal and versatile control of the entire winding process. It should be possible to use modern electronic means with low energy consumption. The gate control should be adaptable to as many different operating conditions as possible. This object is achieved according to the invention with a method having the features in claim 1.

Due to the continuous measurement of the actual value of the thread tension on all threads, the tension behavior of the threads on the entire gate can be detected with a minimum time delay. The measurement is carried out in the range between leaving the gate and winding on the winding machine, which ensures that the different run lengths and deflections of the threads are taken into account. The control process can be customized for individual threads or for particular groups of threads, making the gate versatile. The mechanical function and arrangement of the thread brakes plays only a minor role. By this method, thread influences, such as different thread thicknesses, thread structure, other material influences and influences at the withdrawal point in the creel compensated.

According to the method according to the invention, each individual yarn brake is activated with a drive motor assigned to it. This is readily possible with the miniaturized drives offered today at low cost. Thus, for the first time every single thread on the gate can be controlled individually.

It is also possible for a thread group with the same material properties to specify an identical thread tension setpoint value for each thread and to match the measured actual thread tension within the thread group to the predefined thread tension setpoint value by the thread tension regulation

Further procedural advantages can be achieved if the threads in the thread running direction before each thread brake are acted upon by at least one biasing device with an additional braking force, which is set as the basic value, or which is set depending on the measured actual value.

Depending on the material properties, such as nature, rotation, strength and Krangelneigung, etc. of the threads, different biasing devices must be used to ensure trouble-free operation of the threads. The wrap-around pretensioners, such as eyelet pretensioners, crepe pretensioners, etc., can be adjusted individually or rail-wise with a drive motor for optimum thread drainage.

In addition, it is possible, the different lengths of the threads or thread groups (gate length compensation) exclusively to compensate with the help of the biasing devices. In this way, the subsequent thread brakes are relieved of this mandatory compensation and they can unfold the full efficiency with respect to their braking force.
In addition, the above-mentioned biasing means can also be used to increase the thread tension before entering the thread brakes, wherein the thread tension is also controlled individually or in groups together with the thread brake. But these biasing devices can also be used as the only means for voltage distribution. No additional thread brakes would be required, which is very cost-effective. The term "thread brake" as used herein thus also broadly encompasses all biasing means.

In certain cases, it is advantageous if the tensile force of the combined to form a thread band totality of the threads measured in the area before the winding emergence point as the actual strip tension value and compared with a strip tension setpoint value on the winding machine, and when detecting a deviation all the thread brakes are adjusted simultaneously such that the actual strip tension value approaches the desired strip tension value. This additional control of the strip tension superimposed on the control of the thread tension described above, taking into account all voltage changes between the yarn tension sensors and the winding run-off point.

The invention also relates to a creel for a winding system, which is characterized in the device-moderate terms by the features in claim 4. In such a creel, the thread tension can be measured individually on each individual thread by means of thread tension sensors.

There are basically various principles of yarn tension sensors known. However, sensors which have a force-measuring device with a measuring element which responds to expansion have proved particularly advantageous for the purpose according to the invention, wherein the force occurring transversely to the thread can be measured on the deflected thread. Such a thread tension sensor is for example in the DE-A 197 16 134 described, the disclosure of which is hereby incorporated in its entirety. The sensor is compact in case of small external dimensions and relatively insensitive to contamination. The piezo-resistive measuring bridge requires very little energy, which plays a not insignificant role in the possibly large number of sensors. The measurement also takes place directly linearly with the movement of the probe, thus reducing the possibility of measurement errors.

The thread tension sensor can be functionally also used in a particularly simple manner as a thread monitor for the thread running or thread breakage control of the thread. If the thread tension of one or more threads exceeds or falls below the upper or lower control range, a warning signal is emitted or the winding system can be automatically stopped.

The described functions of the yarn tension sensor can be used in addition to the use for the yarn tension control only as a monitoring function in a winding system for the entire yarn sheet.

Stepper motors are particularly advantageous as a drive motor for the thread brakes (normal pressure yarn brake eg disk brake, looping yarn brake, dynamic yarn brake, etc.) or the aforementioned biasing devices (Ösenvorspanner, Crepevorspanner) used which have a self-locking Gear acting on the brake fluid. The advantage of these stepper motors is that they absorb energy only during activation, but not in the hold phase. This can significantly reduce energy consumption. A self-locking drive motor, for example with a worm gear or a self-locking spindle drive, ensures that a position approached by the stepper motor is maintained. The advantage of the stepping motor is also that at any time the position of the thread brakes or the position of the biasing means are known and can be calibrated.

Each winding unit may be assigned at least one signal component, in particular a thread monitor for the thread running or yarn breakage control of the thread and / or an optical signal means for identifying the winding units or as a plug-on. The thread monitoring can be done according to various known per se functional principles, such as the mechanical Fall needle principle, Hall sensors, optical monitoring means, etc. A signaling means for facilitating the placement of a creel is, for example by the EP-A-329 614 known.

All of a winding unit associated electrically activatable means, in particular the drive motors for the thread brakes, but also, the mentioned signal components can be activated via common signal lines. For this purpose, they are in operative connection via serial interfaces with a central control device. This obviously eliminates a complicated wiring of the individual components.

Fig. 1

eine stark schematisierte Seitenansicht auf ein Spulengatter mit den Merkmalen der Erfindung,

Fig. 2

eine Draufsicht auf das Spulengatter gemäss Fig. 1,

Fig. 3

eine Draufsicht auf eine einzelne Spulstelle mit Vorspannereinrichtungen und mit einer Tellerbremse,

Fig. 4

eine perspektivische Darstellung eines Stützprofils mit darin angeordneten Tellerbremsen, in Gesamtansicht und im Detail,

Fig. 5

eine schematische Seitenansicht einer Spulstelle mit einem Ösenvorspanner, einem Crepevorspanner und mit einer Tellerbremse,

Fig. 6

eine schematische Seitenansicht einer Spulstelle mit einem Ösenvorspanner und mit einer Umschlingungsfadenbremse,

Fig. 7

eine Prinzipdarstellung eines Spulengatters mit fadenweiser Spannungsmessung, einzeln angetriebenen Tellerbremsen und einzeln angetriebenen Ösenvorspannern und Crepevorspannern,

Fig. 8

eine Prinzipdarstellung eines Spulengatters mit fadenweiser Spannungsmessung, einzeln angetriebenen Tellerbremsen und schienenweise angetriebenen Ösenvorspannern und Crepevorspannern,

Fig. 9

eine Prinzipdarstellung eines Spulengatters mit fadenweiser Spannungsmessung, einzeln angetriebenen Umschlingungsfadenbremsen und einzeln angetriebenen Ösenvorspannern.

Fig. 10

eine Prinzipdarstellung eines Spulengatters mit fadenweiser Spannungsmessung, einzeln angetriebenen Umschlingungsfadenbremsen und schienenweise angetriebenen Ösenvorspannern,

Fig. 11

eine perspektivische Darstellung von Gruppen von Fadenspannungssensoren auf verschiedenen Ebenen.

Further advantages and individual features of the invention will become apparent from the following description of exemplary embodiments and from the drawings. Show it:

Fig. 1

a highly schematic side view of a creel with the features of the invention,

Fig. 2

a plan view of the creel according to Fig. 1 .

Fig. 3

a plan view of a single winding unit with biasing means and with a disk brake,

Fig. 4

a perspective view of a support profile with plate brakes arranged therein, in general view and in detail,

Fig. 5

a schematic side view of a winding unit with a Ösenvorspanner, a Crepevorspanner and with a disk brake,

Fig. 6

a schematic side view of a winding unit with a Ösenvorspanner and with a belt thread brake,

Fig. 7

a schematic diagram of a creel with thread-wise tension measurement, individually driven plate brakes and individually driven Ösenvorspannern and Crepe prestressers,

Fig. 8

a schematic diagram of a creel with thread-wise voltage measurement, individually driven plate brakes and rail-driven Ösenvorspannern and Crepe prestressers,

Fig. 9

a schematic diagram of a creel with thread-wise tension measurement, individually driven Umschlingungsfadenbremsen and individually driven eyelet pretensioners.

Fig. 10

a schematic diagram of a creel with thread-wise tension measurement, individually driven Umschlingungsfadenbremsen and rail-driven Ösenvorspannern,

Fig. 11

a perspective view of groups of yarn tension sensors at different levels.

According to the FIGS. 1 and 2 there is a winding system 1, for example, a wastewater treatment plant, from a creel 2 and a winding machine (Konusschär-, Zettel-, Bäumaschine, etc.) 3. The individual thread bobbins 4 are attached to winding units 7 of the creel and the jointly withdrawn threads 5 pass at least ever a yarn brake 6 for maintaining a predetermined yarn tension.

The example shows a parallel gate with a left gate side LS and with a right gate side RS. The coils form vertical and horizontal rows, it being evident that each vertical row forms a group of threads on each side of the gate whose yarn running length from the winding unit to the winding machine is the same. However, the same principle can also be applied to any other type of gate, e.g. in a V-gate.

On the gate coils of different types, for example, different yarn qualities or different thread colors can be plugged regardless of the thread running length at different locations. Independent of the so-called gate length compensation, For example, the threads of different types can each be exposed to an individual braking force.

Fig. 2 shows the two thread groups with the longest run length L1 and the two thread groups with the shortest run length L2.

In the area of the gate side 8, which is closest to the winding machine 3, the thread tension sensors 9 are preferably arranged for each individual thread. However, the arrangement of the thread tension sensors at this point is not mandatory. In principle, it would be advantageous to introduce the thread tension sensors as close as possible to the winding point of the winding machine.

Thus, the yarn tension sensors can also be used in an area in front of the winding point of the winding machine. be arranged between the gel 10 and blade 11 for merging the threads. With appropriate miniaturization of the yarn tension sensors, these can thus be arranged so close together that despite the already made merging of the threads each individual thread can be acted upon. This would even eliminate the previous band tension regulation, because all changes in the braking force can be measured until just before the formation of the winding.

This could also include the thread line between the creel and the winding machine in the control loop. Alternatively, this is also possible because the strip tension regulation known per se is maintained with a common tension measurement of the entire thread structure shortly before winding, so that the individual control process according to the invention is still superimposed by a global control process. Such a band tension regulation is for example by the CH-A-675 598 have become known, the disclosure of which is hereby fully incorporated.

After leaving the creel, the threads pass into the area of the winding machine 3 where they first pass through a flushing sheet 10, in which the threads are given their correct sequence. Subsequently, the threads are fed to the warper blade 11, in which they are brought together to be subsequently wound as a thread assembly 12 via a deflection and / or measuring roller 13 on the winding 15 and on the winding beam 14.

Depending on the intended use of the creel 7 different brake means can be arranged at a winding unit.

Fig. 3 shows, for example, as a abgegewikkelter from a coil 4 thread 5 passes through two biasing means on a belt and a yarn brake. A Ösenvorspanner 16 and a Crepevorspanner (named after the strong twisted Kreppgärn) 17 have in addition to the Vorspannungserteilung the task of raising from the thread formed crane gel and act as a baffle against spin backlog and thus avoid Krangelbildung. At the same time they cause a limitation of the thread balloon, which forms during unwinding of the coil 4.

The wrap of the biasing means 16 and 17 can be adjusted by rail or individually, for example by a rotary or pivoting movement. The main braking force is applied by a disk brake 18 with two in the thread running direction successively arranged brake actuator units. The disk brake is housed in a U-shaped, vertical support profile 19, in the U-leg yarn guide eyelets for the passage of the thread 5 are arranged.

It may also be advantageous if the crepe pretensioners are individually adjustable per thread in order to avoid the formation of kinks in the case of different types of yarn and thus to achieve a good flow behavior of the thread.

Fig. 4 shows more details of such a disk brake. Over each disk brake 18, an individual drive motor 20 is mounted directly in the support section 19. This actuates an adjustment support 22, a pressure element 23 which loads or relieves the brake plates.

The FIGS. 5 and 6 show in a schematic representation winding units with different pretensioners and braking devices. According to Fig. 5 passes through the thread 5 according to the Fig. 3 first a Ösenvorspanner 16 and then a Crepevorspanner 17 before he is guided by the plate brake 18.

Fig. 6 shows an alternative embodiment of a winding unit with a loop thread brake 39. As a biasing device is used only a Ösenvorspanner 16. With the Umlaingungsfadenbremse the twist angle and thus the degree of wrap can be adjusted. As a result, the friction conditions and thus the thread tension are adjusted or regulated. The biasing devices according to the FIGS. 5 and 6 can be adjusted by rail as well as individually by thread.

The schematic representation according to Fig. 7 shows one, with respect to the winding machine 3, distant coil row 24 and a near coil row 25, each with three floors, so each with three winding units. In fact, each vertical row (rail) can have up to 12 floors. The thread tension is measured for all vertical rows (rails) on a common measuring plane 38.

As shown, each thread has its own thread tension sensor 9.

These thread tension sensors can be used to control the thread tension, to monitor the specified thread tension range and as thread breakage monitoring.

Between the spool and the disk brake, the thread passes through a Ösenvorspanner 16 and then a Crepevorspanner 17. These biasing means are each driven by an individual drive motor 20. After the biasing device, the threads reach a disk brake 18, which is also provided individually with a drive motor 20. On the plate brakes of a rail but also a common drive motor 40 can be activated in order to rotate the lower brake plate in a conventional manner to avoid cuts of the threads in the brake plates. It is also very advantageous if the drive motor 40 for the plate drive is controlled such that it can be automatically deactivated on vertical rows (rails) of winding units without threads based on Daseinskontrolle by the thread tension sensors or the thread monitor. By the thread tension sensors or by the thread monitor is always known which winding units are not equipped. As in FIG. 7 indicated, but the lower brake plates of each thread brakes could also each be rotated with an individual drive motor 40 '. In such a case, each motor 40 'is deactivated, the thread brake carries no thread.

In addition, each winding unit is associated with an optical signal element 26 and an acknowledgment switch, which serve as Spulenaufsteckhilfe, and thus facilitate the placement of the creel. The signal element serves the various Set the coil character or coil types correctly according to the prescribed repeat. In addition, the individual thread tension setpoints can be automatically assigned to the corresponding thread types.

Each vertical row (rail) is provided with an electronic node 29, 29 ', which can process 28 different signals via a serial line system. Each gate page has its own main processor 30, 30 'whose activities are coordinated via a transmission processor 31. This can also regulate a gate side individually. The thread tension setpoints can be entered on a display per thread, per thread group or rail by rail. The input SETPOINTS are forwarded by the transmission processor to the main processors 30 and 30 ', where they are compared with the ACTUAL values. The actual values for the thread tension are measured by the thread tension sensors on a common measurement plane 38 and forwarded to the measurement collection units 32 and from there to the main processors 30 and 30 '. These main processors thus assume the function of a comparison device for comparing the actual values with the entered nominal values.

The embodiment according to Fig. 8 differs from the one according to Fig. 7 in that the eyelet pretensioners 16 and the crepe pretensioners 17 can be adjusted by rail with a common drive motor 21. However, the plate brakes 18 also have individual drive motors 20.

In the embodiment according to Fig. 9 in turn, each individual thread is provided with its own thread tension sensor 9. However, instead of plate brakes, as in the previous embodiments, wrap thread brakes 39 are used Insert, which are individually adjustable with an individual drive motor 20. The biasing means are exclusively Ösenvorspanner 16, which are also adjustable via individual drive motors 20.

The embodiment according to Fig. 10 differs according to that according to Fig. 9 only in that all Ösenvorspanner 16 a vertical row (rail) with a common drive motor 21 are adjustable.

Evidently, according to the invention, other combinations would also be conceivable, e.g. by the use of alternative thread brakes or pretensioners or by the omission or addition of further measuring, control or signaling devices at the individual winding units.

In Fig. 11 It is shown how for each floor on the gate, a whole yarn tension sensor battery 34, consisting of the yarn tension sensors 9, is arranged. The attachment takes place on a common support 33. Each sensor has a movable sensor 37 which is arranged between two yarn guides 36, that the yarn 5 is deflected. The actual measuring bridge is arranged in a closed housing 35, wherein the individual housings can be fastened directly next to one another.

The summary of the thread tension sensors in 8-unit has the advantage that these units are mechanically inexpensive, space-saving and electrically compatible with an 8-bit unit.

Claims (17)

1. Method for operating a bobbin creel (2) for a winding plant (1), in particular a warping plant, with a plurality of bobbin stations (7), in which method a plurality of threads (5) of the same or a different generic type are taken off jointly from the bobbin stations by means of a winding machine (3), at each bobbin station the thread being acted upon with a braking force at at least one thread brake (6),
   characterized in that the ACTUAL value of the thread tension is continuously measured on each individual thread (5) in the region between leaving the creel (2) and winding at the winding machine (3), in that the measured actual value of each thread is compared with a corresponding DESIRED value, and in that, when a deviation of the actual value from the desired value is detected, the thread brake (6) of the respective thread is adjusted in such a way that the actual value is approximated to the desired value, each thread brake being activated by means of a drive motor (20) assigned to it.
2. Method according to Claim 1, characterized in that the threads are acted upon, upstream of each thread brake in the thread running direction, at at least one pretensioner device (16, 17) with an additional braking force which is set as a function of the measured ACTUAL value or which is permanently set as a basic value.
3. Method according to Claim 1 or 2, characterized in that, at the winding machine, the tensile force of the whole of the threads, combined into a sliver, is measured in a region upstream of the winding run-on point as a sliver-tension ACTUAL value and is compared with a sliver-tension DESIRED value, and in that, when a deviation is detected, all the thread brakes are simultaneously adjusted in such a way that the sliver-tension actual value is approximated to the sliver-tension desired value.
4. Bobbin creel (2) for a winding plant (1), in particular a warping plant, with a plurality of bobbin stations (7), from which a plurality of threads of the same or a different generic type can be taken off simultaneously by means of a winding machine (3), and with at least one thread brake (6) which is assigned to each bobbin station and at which the thread can be acted upon with a braking force, characterized in that at least one thread-tension sensor (9) is arranged for each thread in the region between the bobbin stations (7) on one creel side (8), which lie nearest to the winding machine (3), and the winding beam (14) of the winding machine (3), at which thread-tension sensor the ACTUAL value of the thread tension of a thread can be measured continuously, in that the actual value of each thread can be compared with a corresponding DESIRED value in a comparator device (30, 30'), and in that, when a deviation of the actual value from the desired value is detected, a drive motor can be activated, by means of which the thread brake (6) of the respective thread can be adjusted in such a way that the actual value is approximated to the desired value, each thread brake being activatable by means of a drive motor (20) assigned to it.
5. Bobbin creel according to Claim 4, characterized in that the thread-tension sensors have a force-measuring device with a measuring element capable of responding to elongation, the force, occurring transversely with respect to the thread, on the deflected thread being measurable.
6. Bobbin creel according to Claim 4 or 5,
   characterized in that a plurality of thread-tension sensors are arranged in a row on each creel tier, each sensor being surrounded by a separate housing.
7. Bobbin creel according to one of Claims 4 to 6, characterized in that each bobbin station is assigned at least one pretensioner device (16, 17), arranged upstream of the thread brake in the thread running direction, for applying an additional braking force which can be driven independently of the thread brake or which can be set permanently as a basic setting.
8. Bobbin creel according to Claim 7, characterized in that the pretensioner device is an eye pretensioner (16) with a rotatable eye deflecting the thread and/or a crepe pretensioner (17) with adjustable looping elements.
9. Bobbin creel according to one of Claims 4 to 8, characterized in that the thread brakes are looping thread brakes with an adjustable looping angle or disc brakes (18) with brake discs acting upon the thread and capable of being subjected to varying load.
10. Bobbin creel according to Claim 7 or 8,
    characterized in that the identical pretensioner devices (16, 17) of a vertical row of bobbin stations are adjustable by means of one common drive motor (21).
11. Bobbin creel according to Claim 7 or 8,
    characterized in that each identical pretensioner device (16, 17) is adjustable by means of a drive motor assigned to it.
12. Bobbin creel according to one of Claims 4 to 11, characterized in that the drive motors for the thread brakes are stepping motors, and in that they act on the thread brakes via a self-locking gear.
13. Bobbin creel according to one of Claims 4 to 12, characterized in that each bobbin station is assigned at least one thread catch device (27) for the thread break control or thread movement control of the thread.
14. Bobbin creel according to one of Claims 4 to 13, characterized in that each bobbin station is assigned at least one optical signal means (26) for identifying the bobbin station and/or as a bobbin attachment aid.
15. Bobbin creel according to one of Claims 4 to 14, characterized in that all the electrically activatable means, in particular the drive motors for the thread brakes, which are assigned to a bobbin station are operatively connected to a central control device via serial interfaces.
16. Bobbin creel according to one of Claims 4 to 15, characterized in that the thread-tension sensors (9) are arranged in a region upstream of the winding run-on point of the winding machine (3) and between a lease and a reed (11) for combining the threads.
17. Bobbin creel according to Claim 9, characterized in that the brake discs for the thread brakes of a vertical row are rotatable by means of one common drive motor, or in that the brake discs for each thread brake are rotatable by means of a drive motor assigned to it, all the drive motors being activatable via the thread-tension sensors or via the thread catch devices in such a way that a drive motor of a vertical row without threads or the drive motors of the thread brakes without threads can be deactivated automatically.

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