EP4051832B1 - Open-end spinning machine, driving process thereof and control unit - Google Patents

Description

The invention relates to an open-end spinning machine with a plurality of work stations, each of which has a spinning device for producing a thread, a thread take-off device for taking the thread out of the spinning device, a storage nozzle for temporarily storing the taken-off thread, a winding device for producing a cross-wound bobbin, and a suction nozzle that can be subjected to negative pressure, and the open-end spinning machine is equipped with at least one service unit that serves several of the work stations, which has an auxiliary thread supply device for supplying an auxiliary thread, and an auxiliary thread take-off, which are used in a piecing process at a work station to be operated, in particular in the course of a cross-wound bobbin/empty tube change, and a method for operating such an open-end spinning machine.

In connection with open-end spinning machines, it has long been known that such textile machines often have a large number of work stations arranged next to one another, which are usually identically designed and each equipped with a plurality of different working elements.

The workstations of such open-end spinning machines can either each have an open-end spinning device which is designed as a rotor spinning device, wherein the spinning rotor, as for example in the publication EP 1 156 142 B1 described, preferably magnetically mounted. Alternatively, the workstations can each be equipped with an open-end spinning device that has an air spinning device. Such air spinning devices are described, for example, in the publication DE 199 26 492 A1 or the printed matter DE 2005 022 186 A1 described in relatively great detail.

Furthermore, the workstations of such open-end spinning machines are often designed as largely self-sufficient workstations, i.e. the workstations of such open-end spinning machines can automatically start spinning again after a thread break. For this purpose, each of the workstations preferably has, in addition to a spinning device and a winding device, a storage nozzle for temporarily storing a produced thread and a suction nozzle that can be subjected to negative pressure, in particular one that is pivotably mounted between the spinning device and the winding device.

Although such self-sufficient workstations can restart spinning automatically after a thread break, open-end spinning machines equipped in this way are often equipped with at least one Equipped with a service unit, which is used during a piecing process at a work station that needs to be operated, in particular when changing cross-wound bobbins/empty tubes. This means that such service units intervene when a cross-wound bobbin has reached a specified diameter at one of the work stations and needs to be replaced with a new empty tube.

Such service units have also been known for a long time and, as described for example in the publication DE 101 39 072 A1 described in quite some detail, usually have numerous different handling devices. Such service units have, for example, an auxiliary thread supply device for providing an auxiliary thread required in connection with a cross-wound bobbin/empty tube change for the re-spinning of a work station, a thread application device for securing the newly spun thread to an empty tube held in a bobbin frame of the winding device of the work station in question, and an auxiliary thread take-off device which is used to take off the newly spun thread and in particular for the disposal of the piecer produced using the auxiliary thread.

The auxiliary thread supply device often has a so-called thread supply tube, which is mounted in an intermediate wall of the service unit so that it can rotate about a pivot axis and can be positioned in a defined manner by means of a stepper motor. A supply spool that provides the required auxiliary thread is connected to the thread supply tube, for example via a rotary union and a pipe and/or hose system. In the area of the pipe and/or hose system, a supply mechanism is also arranged that draws the auxiliary thread from the supply spool, and a thread cutting device is installed that cuts the auxiliary thread after it has been transferred for the last time to the suction nozzle of the work station, which is in particular mounted so that it can pivot. The thread application device of such service units is preferably designed as a pivot arm that can be moved from a rear rest position into the area of the winding device of the work station and has a head element that has a plurality of different handling devices. The head element is equipped, for example, with a thread guide roller, a thread brake and a thread cutting device. Furthermore, the head element of the thread feeding device can have a tube plate opener with which a tube plate of the winding device can be acted upon in such a way that a gap is provided between the tube plate and an end face of an empty tube held in the winding device.

Such service units are also usually equipped with an auxiliary thread take-off, which drives the auxiliary thread frictionally, especially during its disposal. According to the state of the art Technology, the take-off speed of this auxiliary thread take-off corresponds to the thread take-off speed of the thread take-off device at the work station.

As already indicated above, such service units are preferably used when a cross-wound bobbin has reached a predetermined diameter at a work station of an open-end spinning machine and must be replaced with a new empty tube.

In such a case, the service unit is called to the relevant work station, positions itself there and transfers the full cross-wound bobbin from the bobbin frame of the work station to a cross-wound bobbin transport device arranged behind the winding devices, preferably the length of the machine, which transports the cross-wound bobbin to a transfer station usually arranged at the end of the machine. The service unit then places a new empty tube in the bobbin frame of the work station.

Since a piecing thread is required for the subsequent re-piecing of the work station, but the inserted empty tube does not contain any thread material that could be used as a piecing thread, the service unit provides the so-called auxiliary thread. This means that the thread delivery pipe of the auxiliary thread delivery device pivots into a lower operating position and transfers the beginning of the auxiliary thread to a suction nozzle of the work station, which is particularly pivotably mounted and positioned in a so-called thread transfer position. The suction nozzle then pivots downwards and transfers the beginning of the auxiliary thread to a piecing device arranged in the area of the spinning device, which prepares the auxiliary thread for the piecing process. During the pivoting process of the suction nozzle, the auxiliary thread was also threaded into a thread take-off device of the work station.

At the same time or afterwards, the thread feed tube of the auxiliary thread feed device pivots into an upper operating position and the thread feed device pivots in the direction of the winding device of the work station. During this shift, the auxiliary thread provided by the auxiliary thread feed device, which at this point is stretched between the thread take-off device of the work station and the upwardly pivoted thread feed tube, is transferred to the area of the winding device of the work station by means of the handling devices arranged on the head element of the thread feed device of the service unit. This means that the stretched auxiliary thread runs in the area of the winding device through a gap between a tube plate of the winding device and the front side of the inserted empty tube.

The thread delivery pipe of the auxiliary thread delivery device then pivots further clockwise and places the auxiliary thread into the auxiliary thread take-off of the service unit before the auxiliary thread is transferred back to the pivoting suction nozzle, which is again positioned in the thread transfer position. The actual, familiar piecing process then takes place.

After re-spinning, the auxiliary thread, which is now connected to the new spinning thread via a so-called piecing machine, is disposed of. This means that the auxiliary thread or the new spinning thread is drawn off by the thread take-off device of the work station and, guided through the handling elements of the thread laying device and acted upon by the auxiliary thread take-off of the service unit, runs into the pivoting suction nozzle of the work station, which disposes of the auxiliary thread. During this process, increased thread friction occurs, particularly due to the multiple deflection of the auxiliary thread or the new spinning thread in the area of the handling elements of the thread laying device, with the result that a thread loop forms between the thread take-off device of the work station and the auxiliary thread take-off of the service unit, which must be temporarily stored by the storage nozzle of the work station.

As soon as the piecing machine has passed the winding device, i.e. the area of the gap between a tube plate and the empty tube, the new spinning thread is clamped by closing the gap and separated properly by the thread cutting device. The empty tube is then rotated and the new winding process is started.

The spinning thread produced by the open-end spinning device during the clamping and cutting process and continuously drawn off by the thread take-off device of the work station is also temporarily stored in the storage nozzle of the work station.

A disadvantage of the known open-end spinning machines and the processes for operating these textile machines is that both during the disposal of the auxiliary thread and during the clamping and cutting process of the new spinning thread, larger thread loops are created that have to be temporarily stored by the storage nozzle of the work station. This means that due to the often quite large quantities of thread that have to be temporarily stored in the storage nozzle of the work station, problems often arise when the resulting thread loops are subsequently unraveled. This means that there is a risk, for example, that the thread loops in the suction nozzle, which often extend into the vacuum channel of the open-end spinning machine, will become tangled, which either leads to a thread break or that the thread in the the spinning thread stored in the storage nozzle runs onto the empty tube with an undefined thread tension.

Another state-of-the-art open-end spinning machine is also known from the publication EP 2 267 200 A1 known.

Based on the aforementioned prior art, the invention is based on the object of reducing, or at best avoiding, the risk of thread breakage and/or uncontrolled entanglement of a thread loop to be temporarily stored in a storage nozzle of a work station of an open-end spinning machine during a piecing process, in particular during a cross-wound bobbin/empty tube change.

This object is achieved according to a first device-side aspect in that the auxiliary thread take-off is designed and operable in such a way that the auxiliary thread take-off speed of the auxiliary thread take-off for taking off the spun auxiliary thread, preferably at the start of the take-off or from a defined point in time between the start of the take-off and an initiated interruption of the take-off of the spun auxiliary thread, for example by clamping the auxiliary thread in the thread path in front of the auxiliary thread take-off, has a speed offset in which the thread take-off speed of the thread take-off device of the work station and at least one further correction factor are taken into account. The preferred defined point in time can be selected in such a way that the thread loop running into the storage nozzle has a predeterminable size and/or length at the latest at the time of the initiated interruption of the take-off of the spun auxiliary thread.

According to the invention, a control device which is wirelessly or wired coupled to the open-end spinning machine and is designed to generate and transmit a control command for operating the auxiliary thread take-off for taking off the spun auxiliary thread at the auxiliary thread take-off speed having the speed offset, which takes into account the thread take-off speed of the thread take-off device and at least the further correction factor. The control device can preferably be a component of the open-end spinning machine, for example a component of a central control device controlling the open-end spinning machine or a work station control device controlling the work station of the open-end spinning machine or a service unit control device controlling at least one service unit. Alternatively, the control device can be an external control device independent of the open-end spinning machine, such as a higher-level It can be a control device for controlling several textile machines or a mobile control device which can be or can be coupled to the open-end spinning machine wirelessly or via cable for transmitting the control command.

The task is further solved in terms of the method in that after a step of producing a piecing using an auxiliary thread supplied by the service unit, a step of pulling off the spun auxiliary thread using the thread pulling device and the auxiliary thread pulling takes place, wherein the auxiliary thread pulling is operated, preferably at the start of pulling or at least from a defined point in time before an initiated interruption of the pulling off of the spun auxiliary thread, for example by clamping the auxiliary thread in the thread path before the auxiliary thread pulling, with an auxiliary thread pulling speed having a speed offset which takes into account the thread pulling speed of the thread pulling device and at least one further correction factor. The defined point in time can be selected as described above. Further preferably, such operation of the auxiliary thread pulling can take place at least until shortly before or until the time of the initiated interruption, further preferably also after the time of the initiated interruption, for example to dispose of the auxiliary thread. The latter offers the particular advantage that it is possible to dispense with the generation and issuing of a modified control command.

Advantageous embodiments of the present invention are the subject of the subclaims.

The inventive design of the auxiliary thread take-off of a service unit has the particular advantage that, due to the consideration of at least one further factor influencing the thread path of the spun auxiliary thread during its take-off, in particular during its disposal, an adjustment of the auxiliary thread take-off speed of the auxiliary thread take-off of the service unit to the thread take-off speed of the thread take-off device of the work station can be ensured. This means that it can be reliably guaranteed that the thread loop running into the storage nozzle of the work station during the disposal of the auxiliary thread does not take on such a shape or size that leads to a thread break or tangling of the thread loop. By minimizing the thread loop that arises during the take-off or disposal of the auxiliary thread to a predeterminable size and/or length at the latest at a time when the take-off is interrupted, it can also be ensured that there is enough space in the storage nozzle of the work station to easily accommodate the often relatively large thread loop of the new spun thread that inevitably arises in the subsequent work step.

According to a preferred embodiment, the at least one correction factor to be taken into account is a thread friction of the auxiliary thread or a time difference between the start of the thread withdrawal device and the start of the auxiliary thread withdrawal is a correction factor to be taken into account. In particular, in a manual or automatically generated selection or setting of the auxiliary thread take-off speed, a speed profile is preferably selected or set which is above the speed profile of the thread take-off device of the work station in a defined manner, whereby it can be ensured that only a relatively small excess of thread or no excess of thread is created which has to be temporarily stored in the storage nozzle. The manual selection can be made via an input device which is coupled to the open-end spinning machine or the control device or which can be coupled wirelessly or by cable. The automatically generated selection can be made, for example, by the control device, wherein the control device can preferably be connected to a knowledge store in which speed profiles are stored in a retrievable manner. Alternatively or additionally, the control device can be designed to generate the speed profile to be selected or set or regulated taking into account a predetermined or continuously (for example periodically, aperiodically, continuously) determined speed profile of the thread take-off device of the spinning station and the at least one further correction factor. Furthermore, alternatively or additionally, the control device can be designed to receive a corresponding speed profile for setting the same.

In a further preferred manner, the speed offset is selected or adjustable or controllable in such a way that a thread loop entering the storage nozzle of the work station during the withdrawal or disposal of the spun auxiliary thread has a defined size and/or length, the length preferably being 25 mm or less, more preferably 10 mm or less. Alternatively or additionally, it is preferred if the penetration depth of the thread loop into the storage nozzle, which makes up the size of the thread loop, is less than 10 mm, more preferably less than 5 mm. In this way, on the one hand, the length of the incoming thread loop and, additionally or alternatively, the penetration depth of the thread loop into the storage nozzle can be adapted or set as required, whereby the risk of thread breakage and/or tangling of the thread loop can be minimized or, at best, prevented.

By such a significant reduction in the size and/or length of the thread loop entering the storage nozzle, it can be ensured in a preferred manner that in a subsequent operation such as preferably clamping the spun auxiliary thread, for example in the course of laying it on an empty tube or in the course of splicing with an upper thread end coming from the cross-wound bobbin, in which a not inconsiderable amount of the new spun thread is inevitably created, which in the storage nozzle must be temporarily stored, it is ensured that there is still sufficient space in the storage nozzle for a relatively large thread loop. This means that before the subsequent work step, in which the new spun thread is placed on the empty tube held in the winding device of the work station or is inserted into a splicing device for splicing and clamped in each case and in the process is briefly stopped, even though the thread take-off device of the work station is constantly supplying new spun thread, it is guaranteed that by far the largest part of the storage nozzle is always empty and can therefore temporarily store new spun thread. Following the clamping process, during which the spun-on auxiliary thread is separated, the auxiliary thread take-off for disposing of the severed section of the auxiliary thread can preferably be operated at an auxiliary thread take-off speed that can be selected as required for the safe and, if necessary, rapid disposal of the severed auxiliary thread section. Therefore, operation of the auxiliary thread take-off at the auxiliary thread take-off speed having the speed offset preferably only needs to be provided until the auxiliary thread is clamped.

In terms of the process, it can also be reliably ensured that the size and/or length of the thread loop entering the storage nozzle of the work station does not exceed a value that may be recognized as problematic during operation with an auxiliary thread withdrawal speed having the speed offset. This means that the auxiliary thread withdrawal of the service unit can be operated with an auxiliary thread withdrawal speed that is adapted to the respective existing thread delivery speed or thread withdrawal speed of the thread withdrawal device of the work station plus at least one correction factor, it is ensured that the thread loop that is created during the withdrawal or disposal of the spun auxiliary thread and enters the storage nozzle has a reduced size and/or length that can be selected as required.

Consequently, sufficient space can be provided in the storage nozzle of the work station to easily accommodate the relatively large loop of the new spinning thread that is created during the subsequent operation or work step.

According to a preferred embodiment, the service unit has a design as described in detail above in conjunction with one of the above preferred embodiments.

In a preferred embodiment of the method, the speed offset is selected or controlled in such a way that, in addition to the thread take-off speed of the thread take-off device of the work station, additional thread friction conditions and/or time differences that exist with regard to the start of the thread take-off device of the work station and the auxiliary thread take-off can be taken into account.

In particular, by taking into account the thread friction conditions, which can be the result of relatively high mechanical friction forces caused by multiple deflections of the auxiliary thread to be pulled off around the operating elements arranged on the head element of the thread application device, it is possible in a relatively simple and precise manner to minimize the size and/or length of the thread loop entering the storage nozzle of the work station during the pulling off or disposal of the auxiliary thread.

Furthermore, when setting the auxiliary thread take-off speed of the auxiliary thread take-off of the service unit or the speed offset, it is also advantageous to take into account that the thread take-off device of the work station and the auxiliary thread take-off of the service unit do not start at exactly the same time. Time differences can occur, particularly in connection with the transmission of start signals, which can thus be taken into account in a preferred manner.

Further details of the invention can be taken from an embodiment explained below with reference to the drawings.

Fig. 1

schematisch eine Hälfte einer Offenend-Spinnmaschine, mit einem an einer Arbeitsstelle der Offenend-Spinnmaschine positionierten Serviceaggregat nach einem Ausführungsbeispiel zur Durchführung eines Verfahrens nach einem Ausführungsbeispiel,

Fig. 2

in einem größeren Maßstab und ausschnittsweise das in Figur 1 dargestellte Serviceaggregat während des Abzuges eines in der Spinnvorrichtung der Arbeitsstelle an einen neuen Spinnfaden angesponnenen Hilfsfadens durch die Fadenabzugseinrichtung der Arbeitsstelle und den Hilfsfadenabzug des Serviceaggregates.

It shows:

Fig.1

schematically one half of an open-end spinning machine, with a service unit positioned at a work station of the open-end spinning machine according to an embodiment for carrying out a method according to an embodiment,

Fig.2

on a larger scale and in sections the Figure 1 The service unit shown during the withdrawal of an auxiliary thread spun onto a new spinning thread in the spinning device of the work station by the thread withdrawal device of the work station and the auxiliary thread withdrawal of the service unit.

In Figure 1 One half of an open-end spinning machine 1 is shown, which is designed, for example, as an air spinning machine or as a rotor spinning machine. Such textile machines generally have a large number of work stations 2, each of which is equipped with, among other things, a spinning device 3 and a winding device 4. In the spinning device 3, a fiber band 6 placed in a spinning can 5 is spun into a thread 7, which is then wound onto the winding device 4 to form a cross-wound bobbin 8. For this purpose, the winding device 4 is equipped with a bobbin frame 9 for rotatably holding an empty tube 10 or the tube of a cross-wound bobbin 8 and a winding drum 11 for driving these elements.

Furthermore, such work stations 2 each have a piecing device 20 installed in the area of the spinning device 3, a thread take-off device 25, a storage nozzle 26 connected to a machine-length vacuum channel 27 of the textile machine and a thread traversing device 18 arranged in the area of the winding device 4.

Such work stations 2 are also each equipped with a work station-specific, pivotably mounted suction nozzle 14, which makes the work stations 2 largely self-sufficient work stations 2. This means that the work stations 2 are equipped in such a way that they can automatically repair thread breaks if necessary.

Such open-end spinning machines 1 also often have a cross-wound bobbin transport device 12 for disposing of the cross-wound bobbins 8 completed on the winding devices 4 of the work stations 2.

Furthermore, at least one service unit 16 is arranged on or on the spinning machine 1, for example movable on a guide rail 13 and a support rail 15, the running gear 17 of which consists, for example, of rollers or a support wheel 19.

As is known per se, such service units 16 are preferably supplied with electrical energy via a sliding contact device (not shown) or via a drag chain. Such service units 16 either constantly patrol along the work stations 2 during the spinning/winding operation of the open-end spinning machine 1 and intervene automatically if there is a need for action at one of the work stations 2, or the service unit 16 is requested by a work station 2 when required and then positions itself at the relevant work station 2. Such a need for action exists, for example, if a cross-wound bobbin 8 has reached a predetermined diameter at one of the work stations 2 and must be replaced with a new empty tube 10. Such a need for action can also exist if a thread break has occurred, which is to be repaired by means of a splicing process.

In order to be able to carry out a proper cross-wound bobbin/empty tube change, such service units 16 have numerous handling devices. Of these numerous handling devices, Fig.1 the auxiliary thread delivery device 21 is shown with a pivotably mounted thread delivery tube 22. Furthermore, such service units 16 each have a movably mounted thread application device 23 and an auxiliary thread take-off 28, which is preferably designed as a mechanically operating roller delivery mechanism. The thread delivery tube 22 of the auxiliary thread delivery device 21 is rotatably mounted on an intermediate wall of the service unit 16 and can be controlled in a defined manner, for example by means of a stepper motor. A supply spool of the auxiliary thread delivery device 21 is connected to the thread delivery tube 22, for example via a rotary feedthrough and a pipe system, which provides the auxiliary thread 24 required when changing a cross-wound bobbin/empty tube. In the area of the pipe system of the auxiliary thread delivery device 21, a thread cutting device is also installed, which cuts the auxiliary thread 24 as required.

The thread application device 23 has a head element 30 at the end, which is equipped with various operating elements. The head element 30 has, for example, a thread cutting device 31, a tube plate opener 32, a thread deflection roller 33 and a thread brake 35.

The Figure 2 shows on a larger scale a detail of a work station 2 as well as a schematic view of a service unit 16 during the disposal of an auxiliary thread 24 required in connection with a cross-wound bobbin/empty tube change.

The auxiliary thread 24 had been applied shortly before in the spinning device 3 of the work station 2, for example to a fiber ring circulating in the spinning device 3 and is now disposed of.

As can be seen, the auxiliary thread 24, which is connected to the new spinning thread 7 via a so-called piecing device 29, is drawn off from the spinning device 3 by the thread draw-off device 25 of the work station 2 and the auxiliary thread draw-off device 28 of the service unit 16 and disposed of through the pivotably mounted suction nozzle 14 of the work station 2.

The auxiliary thread 24 or the new spinning thread 7 is guided on its way to the suction nozzle 14 through the thread feed device 23, which is in its working position A and which has, among other things, a thread brake 35, a thread cutting device 31 and a thread deflection roller 33 in the area of its head element 30. The head element 30 is also equipped with a tube plate opener 32, which ensures that between the front side of an empty tube 10 held in the bobbin frame 9 and one of the tube receiving plates of the There is a gap in the bobbin frame 9 through which the auxiliary thread 24 or the new spinning thread 7 run during their disposal.

The thread strand deflected at the thread deflection roller 33 then runs to the auxiliary thread take-off 28 of the service unit 16 and from there to the suction nozzle 14, which is positioned in its thread take-up position FA.

On its way from the thread take-off device 25 of the work station 2 to the auxiliary thread take-off 28 of the service unit 16, the thread strand also passes through a vacuum-loaded storage nozzle 26 of the work station 2, which ensures that any excess thread is temporarily stored.

Procedure according to a preferred embodiment:

When a cross-wound bobbin 8 has reached its specified diameter at one of the work stations 2, the service unit 16 is ordered to the relevant work station 2, for example by the central control unit of the open-end spinning machine 1, and there, as is known, automatically exchanges the full cross-wound bobbin 8 for a new empty tube 10. This means that after the full cross-wound bobbin 8 has been ejected onto a machine-length cross-wound bobbin transport device 12 by corresponding handling devices (not shown), the service unit 16 places a new empty tube 10 between the tube plates of the bobbin frame 9 of the relevant work station 2.

Since an auxiliary thread 24 is required to re-spin the work station 2, the suction nozzle 14 of the work station is then pivoted into a thread take-up position FA, as is known from the state of the art, and at the same time the thread delivery pipe 22 of the auxiliary thread delivery device 21 of the service unit 16 is positioned in a thread transfer position, for example by means of a stepper motor. This means that the thread delivery pipe 22 is pivoted so far that the mouth of the thread delivery pipe 22 is positioned in front of the suction opening of the suction nozzle 14.

Subsequently, the thread delivery tube 22, which, as explained above, is connected to an auxiliary thread delivery device 21, is pneumatically actuated in such a way that an auxiliary thread 24 emerges from the mouth of the thread delivery tube 22 and is immediately sucked in by the vacuum-loaded suction nozzle 14 of the work station 2.

The thread feeding device 23 of the service unit 16 is still positioned in its locking position R at this time.

Finally, the thread feed tube 22 is pivoted into an upper operating position (not shown) and the auxiliary thread 24 is supplied accordingly by the auxiliary thread feed device 21. While the thread feed tube 22 is pivoted into the upper operating position, the auxiliary thread 24 is pulled over the thread deflection roller 33 of the thread feed device 23, which is still positioned in its locking position R at this time.

In the next step, the thread laying device 23 is pivoted forward into its working position A. The auxiliary thread 24 guided in the thread deflection roller 33 of the thread laying device 23 of the service unit 16 is threaded into a thread cutting device 31 arranged on the head element 30 of the thread laying device 23 and a thread brake 35.

At the same time or subsequently, the suction nozzle 14, which pneumatically fixes the auxiliary thread 24, is moved into the Figure 1 The auxiliary thread 24 is then pivoted downwards into the position shown in dashed lines, threads the auxiliary thread 24 into the thread take-off device 25 of the work station 2 and then transfers the auxiliary thread 24 to the piecing device 20 of the work station 2.

In a corresponding thread preparation device of the piecing device 20, for example a pneumatically actuated preparation tube, the thread end of the auxiliary thread 24 is then prepared for the subsequent piecing process and the auxiliary thread 24 is kept ready for the piecing process by the thread take-off device 25.

Subsequently, the now free suction nozzle 14 swings back upwards into its thread take-up position FA.

In addition, the thread delivery tube 22 of the auxiliary thread delivery device 21 pivots further in the pivoting direction U in a clockwise direction and positions itself again in the thread transfer position. In the course of this pivoting movement of the thread delivery tube 22, the auxiliary thread 24 is also threaded into the auxiliary thread take-off 28 of the service unit 16.

The auxiliary thread 24 is then cut by a thread cutting device arranged within the auxiliary thread delivery device 21 and exits from the mouth of the thread delivery tube 22 due to the blowing flow prevailing in the tube system of the auxiliary thread delivery device 21. and is immediately sucked into the suction nozzle 14 due to the negative pressure in the area of the suction opening of the suction nozzle 14. This means that the auxiliary thread 24 is now stretched between the thread take-off device 25 of the work station 2 and the work station's own suction nozzle 14 and runs through various operating elements of the thread application device 23 and through the auxiliary thread take-off 28 of the service unit 16.

The thread feed device 23 is then controlled in such a way that it tilts one of the tube plates of the winding device 4 slightly outwards using a so-called tube plate opener 32. A wedge-shaped gap is created between the tube plate of the bobbin frame and the front side of the tube foot of an empty tube 10 held in the bobbin frame 9, through which the thread chord of the auxiliary thread 24 runs. The auxiliary thread 24 guided in the thread deflection roller 33 of the thread feed device 23 also runs through the thread cutting device 31 and the thread brake 35 of the thread feed device 23.

To re-spin work station 2, a small length of the auxiliary thread 24 is first fed back in the direction of the spinning device 3 by the auxiliary thread take-off 28 of the service unit 16 and temporarily stored in the storage nozzle 26 of work station 2. Then a precisely defined length of the auxiliary thread 24, which has since been prepared and held ready by the piecing device 20 of work station 2, is fed back into the spinning device 3 by the thread take-off device 25 of work station 2 and there applied to a circumferential fiber ring, which is broken open in the process. The auxiliary thread 24, which is now connected to the new spinning thread 7 via a so-called piecing device 29, is then pulled off via the thread take-off device 25 of work station 2 and the auxiliary thread take-off 28 of service unit 16 and disposed of via the suction nozzle 14 of work station 2.

According to a preferred embodiment, the auxiliary thread take-off 28 of the service unit 16 is designed and adjustable in such a way that the auxiliary thread take-off speed Avs of the auxiliary thread take-off 28 is adapted to the thread take-off speed A _VA of the thread take-off device 25 of the work station 2, with further consideration of a correction factor that takes thread friction into account. Both the length and a penetration depth t of a thread loop 34 entering the storage nozzle 26 of the work station 2 during the disposal of the auxiliary thread 24 can thus be set to an optimal, i.e. small, value, which is preferably only a few mm.

As soon as the auxiliary thread 24 together with the piecing 29 has been disposed of through the suction nozzle 14, the spinning thread 7 is applied to the empty tube 10 and a thread reserve is wound. a cross winding. This means that several quick actions are carried out one after the other by the operating elements arranged on the head element 30 of the thread feeding device 23.

The new spun thread 7 is cut, for example, by the thread cutting device 31 just behind the empty tube 10 and at the same time clamped by the thread brake 35, which is arranged just in front of the empty tube 10. The cut-off piece of thread, which is still running over the auxiliary thread take-off 28 of the service unit 16, is disposed of via the suction nozzle 14. Immediately after the thread separation, the head element 30 of the thread feeding device 23 or the tube plate opener 32 is also controlled so that the previously tilted tube plate is closed again and the spun thread 7 is clamped between the front side of the empty tube 10 and the tube plate. Immediately after the thread brake 35 is opened, the winding drum 11 is started and accelerates the empty tube 10, which lies frictionally on the winding drum 11, to winding speed. Subsequently, the thread application device 23 of the service unit 16 is pivoted back into its rest position R, so that the spinning thread 7 is released in the area of the winding device 4 and can be taken over by the thread traversing device 18 of the work station 2.

During part of the aforementioned processes, in particular due to the action of the thread brake 35 and the clamping of the spinning thread 7 between the tube plate and the empty tube 10, the new spinning thread 7 comes to a standstill.

However, since the spinning device 3 of the work station 2 continuously produces spinning thread 7, which is drawn off by the thread take-off device 25 of the work station 2, a relatively large excess of thread is created, which must be temporarily stored in the storage nozzle 26 of the work station 2.

Since during the previous disposal of the auxiliary thread 24 it was ensured by optimally coordinating the thread take-off speeds of the various thread take-off devices taking into account at least one further correction factor that at this point in time only a very small thread length is temporarily stored in the storage nozzle 26, the storage nozzle 26 still has sufficient storage space to properly temporarily store the excess thread, which has often been somewhat problematic due to its size.

According to an embodiment not shown, a splicing device can be provided, which can either be part of the open-end spinning machine or the service unit. The splicing device can be arranged close to the thread path or can be placed near of the thread path or with the splice channel congruent to the thread path. Such splicing devices are common in the field of air spinning machines, for example.

In the event of a thread breakage, the auxiliary thread provided by the service unit is introduced into the spinning device in an appropriate manner in order to subsequently produce a piecer in a known manner, whereby the auxiliary thread has been transferred to the processing area of the splicing device or is transferred after the piecer has been produced.

An upper thread end that has accumulated on the cross-wound bobbin can be caught in a known manner, for example by means of a pivoting suction nozzle, and transferred to the processing area of the splicing device. The transfer of the upper thread and the auxiliary thread to the area of the splicing device can be coordinated as required.

After the piecer has been produced, the spun auxiliary thread or the spinning thread is preferably pulled off using the thread take-off device and the auxiliary thread take-off until the piecer has passed the cutting device of the splicing device for the spinning thread. After passing the cutting device of the splicing device for the spinning thread, the spinning thread is clamped and cut while the spinning thread is continuously pulled off using the thread take-off device, whereby the storage nozzle fills up as a thread loop runs in and the severed section of the auxiliary thread is disposed of via the auxiliary thread take-off. The upper thread is also clamped and cut, with the clamping and cutting of the upper thread being timed to coincide with the clamping and cutting of the spinning thread. The cut ends of both the spinning thread and the upper thread are opened and prepared in a known manner, for example using the holding and opening tubes of the splicing device. The opened and prepared ends are preferably brought into the splicing channel using a thread guide fork of the splicing device and spliced together using compressed splicing air. After the splicing process, the cross-wound bobbin is accelerated to continue winding at a winding speed such that the storage nozzle is emptied or the thread loop running into the storage nozzle is opened. As soon as the storage nozzle is emptied or the thread loop is opened, the winding of the cross-wound bobbin is continued at a winding speed that is matched to the thread take-off speed of the thread take-off device.

According to a further embodiment not shown, the auxiliary thread take-off is coupled to a control device which is designed to provide a control command for operating the Auxiliary thread take-off for taking off the spun auxiliary thread at an auxiliary thread take-off speed having a speed offset and transmitting it to operate the auxiliary thread take-off, wherein the speed offset takes into account the thread take-off speed of the thread take-off device and at least one further correction factor. According to one embodiment, the control device is a component of the open-end spinning machine, in particular a component of the service unit, and according to an alternative embodiment, is designed as an external or mobile control device which is coupled to the open-end spinning machine wirelessly or by cable for transmitting the control command.

List of reference symbols

1 Open-end spinning machine 23 Thread feeder 2 place of work 24 Auxiliary thread 3 Spinning device 25 Thread take-off device 4 Winding device 26 Storage nozzle 5 Spinning can 27 Vacuum channel 6 Sliver 28 Auxiliary thread take-off 7 thread 29 Piecer 8th Cross-wound bobbin 30 Head element 9 Bobbin frame 31 Thread cutting device 10 Empty tube 32 Shell plate opener 11 Spool drum 33 Thread pulley 12 Cross-wound bobbin transport device 34 Thread loop 13 Guide rail 35 Thread brake 14 Suction nozzle 15 Support rail 16 Service unit FA Thread take-up position 17 drive R Locking position 18 Thread traversing device A Working position 19 Support wheel U Panning direction 20 Piecing organ t Penetration depth 21 Auxiliary thread delivery device Avs Trigger speed of 28 22 Thread delivery tube A _VA Trigger speed of 25

Claims (10)

1. Open-end spinning machine (1) coupled wirelessly or by cable to a control device for transmitting a control command, wherein the open-end spinning machine comprises a plurality of workstations (2), each of which has: a spinning device (3) for producing a thread (7); a thread take-up device (25) for taking up the thread (7) from the spinning device (3); an accumulator navel (26) for temporarily storing the taken-up thread (7); a winding device (4) for producing a cross-wound package (8); and a suction nozzle (14), which can be subjected to a vacuum,

   wherein the open-end spinning machine (1) being equipped with at least one service unit (16), which serves several of the workstations (2) and which has an auxiliary thread delivery device (21) for delivering an auxiliary thread (24) and an auxiliary thread take-up (28), which are used during a piecing process at a workstation (2) to be served, in particular in the course of a cross-wound package/empty tube change,

   characterised in that

   the auxiliary thread take-up (28) is configured and can be operated in such a way that an auxiliary thread take-up speed (Avs) of the auxiliary thread take-up (28) for the take-up of the pieced auxiliary thread (24) has a speed offset, which takes into account the thread take-up speed (A_VA) of the thread take-up device (25) and at least one further correction factor, and

   the control device is designed to generate and transmit a control command for operating the auxiliary thread take-up (28) for the take-up of the pieced auxiliary thread (24) with the auxiliary thread take-up speed (Avs) having the speed offset, which takes into account the thread take-up speed (A_VA) of the thread take-up device (25) and at least the further correction factor.
2. Open-end spinning machine (1) according to claim 1, characterised in that the at least one further correction factor to be taken into account is a correction factor taking into account thread friction of the auxiliary thread (24) or a time difference between the start of the thread take-up device (25) and the start of the auxiliary thread take-up (28).
3. Open-end spinning machine (1) according to claim 1 or 2, characterised in that the speed offset is selected or can be controlled in such a way that a thread loop (34) running into the accumulator navel (26) has a defined size and/or length.
4. Open-end spinning machine (1) according to claim 3, characterised in that the speed offset is selected or can be set or controlled in such a way that the length of the thread loop (34) running into the accumulator navel (26) is 25 mm or less, at least at a defined point in time of an initiated interruption of the take-up, preferably by clamping the pieced auxiliary thread in the thread path upstream of the auxiliary take-off, and/or a depth of penetration (t) of the thread loop (34) into the accumulator navel (26), which depth of penetration (t) constitutes the size of the thread loop (34), is less than 10 mm.
5. Open-end spinning machine (1) according to one of the preceding claims, characterised in that the control device is a component of the open-end spinning machine (1).
6. Method for operating an open-end spinning machine (1) according to one of the preceding claims,
   characterised in that,
   after a step of producing a piecing by means of an auxiliary thread (24) supplied by the service unit (16), there is a step of taking up the pieced auxiliary thread (24) by means of the thread take-up device (25) and the auxiliary thread take-up (28), the auxiliary thread take-up (28) being operated for taking up the pieced auxiliary thread (24) at an auxiliary thread take-up speed (Avs) having a speed offset, which takes into account the thread take-up speed (A_VA) of the thread take-up device (25) and at least one further correction factor.
7. Method according to claim 6, characterised in that the speed offset is selected or controlled in such a way that a thread loop (34) of the pieced thread, which thread loop (34) is to be received by the accumulator navel (26), assumes a defined size and/or length.
8. Method according to claim 6 or 7, characterised in that the at least one further correction factor is a correction factor which takes into account the thread friction of the auxiliary thread (24), by means of which correction factor mechanical friction forces generated by thread deflection and/or thread contact and/or pneumatic friction forces caused by air friction are taken into account.
9. Method according to one of claims 6, 7 or 8, characterised in that the at least one further correction factor or a further correction factor is a correction factor taking into account a time difference between the start of the thread take-up device (25) and the start of the auxiliary thread take-up (28).
10. Method according to one of claims 6, 7, 8 or 9, characterised in that the auxiliary thread take-up (28) is operated at the auxiliary thread take-up speed (Avs) having the speed offset from the start of the take-up step or from a defined point in time after the start of the take-up step at least until a step of clamping the auxiliary thread (24) in the thread path upstream of the auxiliary thread take-up (28).

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