METHOD FOR SEPARATING A SLIVER DELIVERED OUT OF A SLIVER CAN AT A SPINNING STATION OF A SPINNING MACHINE, AND SPINNING MACHINE

Abstract

A spinning machine and method separate a sliver delivered out of a sliver can at a spinning station of the spinning machine. The sliver is delivered out of the sliver can with a supply device at the spinning station in a delivery direction to a spinning device, and is guided by a sliver guide between the sliver can and the supply device. The sliver is clamped in the supply device at the spinning station. In order to separate the sliver, the supply device is driven counter to the delivery direction, wherein the sliver is returned by the supply device and, as a result, the clamping of the sliver in the supply device is released.

Description

FIELD OF THE INVENTION

The present invention relates to a method for separating a sliver delivered out of a sliver can at a spinning station of a spinning machine, wherein the spinning station includes a spinning device and a supply device, by means of which the sliver is delivered out of the sliver can at the spinning station and in which the sliver is clamped at the spinning station. Moreover, the invention relates to a spinning machine that includes a plurality of adjacently arranged spinning stations and sliver cans placed in at least one row underneath the spinning stations, wherein the spinning stations each include a supply device for delivering a sliver out of one of the sliver cans at the spinning station.

BACKGROUND

At spinning machines, it can become necessary for various reasons to separate the sliver delivered at the spinning station. For cleaning purposes, for example, it can become necessary to separate the sliver, clean the spinning station, and subsequently piece the sliver. It can also become necessary within the scope of a lot change or during an exchange of the sliver can to separate the sliver if the lot change or the exchange of the sliver can is to be carried out with a sliver can that is not yet completely empty. It is possible, for example, to simply allow the sliver to tear when the sliver can to be exchanged is removed from the spinning machine. A separation of this type takes place in a completely undefined manner, however, and can result in yarn defects as the remaining sliver residue is spun.

DE 25 21 851 A1 therefore describes separating the sliver in a controlled manner with a smooth cut by means of a separating device. For this purpose, an appropriate separating device is to be arranged at each spinning station. The remaining sliver residue is spun, wherein, due to the smoothly cut sliver end, the yarn forms a thick place at the end of the yarn in the form of a fiber bundle.

DE 39 28 648 A1 describes a can change process in which sliver cans are exchanged by means of a can change trolley. The can change trolley is designed to be able to exchange sliver cans from the front row and sliver cans from the back row. The can change trolley includes a separating device in order to achieve a defined separation of the sliver at sliver cans that are not yet completely empty. Yarn defects can arise in this case as well.

SUMMARY OF THE INVENTION

A problem addressed by the present invention is therefore that of eliminating the disadvantages known from the prior art, in particular of avoiding yarn defects due to the separation of the sliver. Additional objects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.

The problems are solved using a method and a spinning machine having the features described and claimed herein.

In a method for separating a sliver delivered out of a sliver can at a spinning station of a spinning machine, the spinning station includes a spinning device and a supply device, by means of which the sliver is delivered out of the sliver can at the spinning station in a delivery direction and in which the sliver is clamped at the spinning station. It is provided that, in order to separate the sliver, the supply device is driven counter to the delivery direction, wherein the sliver is returned by means of the supply device and, as a result, the clamping in the supply device is released.

In an appropriate spinning machine that includes a plurality of adjacently arranged spinning stations and that includes sliver cans placed in at least one row underneath the spinning stations, the spinning stations each include a supply device for delivering a sliver out of one of the sliver cans at the spinning station. It is provided that the spinning station and/or the spinning machine include(s) a control unit for carrying out the above-described method.

In other words, in order to separate the sliver, the supply device is operated counter to the delivery direction during production. As a result, before the sliver enters the spinning device, the sliver is separated from the spinning device and no sliver residue remains at the spinning station. It is therefore neither necessary to remove a remaining sliver residue from the spinning station, nor can a remaining sliver residue result in yarn defects. Since, in addition, due to the return, the clamping of the sliver in the supply device is simultaneously also released, the sliver, which has now been separated, can be returned in entirety to the sliver can during a sliver can change.

For example, at a rotor spinning machine, the supply device is a feeder that is briefly operated counter to its regular direction of rotation during production in order to carry out a return. As a result, the sliver that is clamped during operation between a feed roller of the feeder and a feed trough assigned to the feed roller is separated from the spinning device immediately before the sliver enters the spinning device and is simultaneously conveyed out of the clamping point. The clamping of the sliver in the supply device is therefore simultaneously released, and so the end of the separated sliver is free.

The method can also be used on an air-jet spinning machine. The supply device is a drafting system in this case, which is briefly driven backward in order to separate the sliver, as the result of which the sliver entering the spinning device is returned. The sliver is clamped in the roller pairs of the drafting system in this case. Due to the return of the sliver and driving the drafting system in the direction counter to the regular delivery direction, the sliver is separated immediately before the sliver enters the spinning device in this case as well and is conveyed out of the drafting system by means of the roller pairs of the drafting system. As a result, the clamping of the sliver in the supply device is simultaneously released, and so the end of the separated sliver is free.

Advantageously, in this case, a draft between the various roller pairs of the drafting system is established in reverse order in comparison to the draft during regular production. As a result, it can be ensured that the sliver does not become jammed during the return, which can occur, for example, at a condenser assigned to the drafting system.

Preferably, the spinning device is initially stopped before the supply device is driven counter to the delivery direction. The units of the spinning station can be shut down in a controlled manner and in coordination with one another. Yarn defects, which could otherwise arise during the delivery of the sliver, can be avoided as a result. This is not necessary, however. A thread break can also be generated due to the driving counter to the delivery direction.

It is also advantageous when the sliver, after having been separated, is unthreaded from a sliver guide of the spinning station. As a result, the sliver is no longer connected to the spinning machine at any point and, as a result, can be easily removed from the spinning machine together with the sliver can to be exchanged during a can change.

It is advantageous when the separation of the sliver is carried out within the scope of an automatic can change process. An at least partially emptied sliver can to be removed is removed from the spinning machine and replaced by a full sliver can. By means of the method, the sliver can be separated in a reliable manner and free of residue, i.e., without any sliver residue remaining. The sliver cans can be easily exchanged as a result, even though the sliver cans still contain some residual product. Due to a preventive sliver can change of this type, downtimes of the spinning devices, which can occur when the sliver cans are emptied, can be avoided. The productivity of the spinning machine can be increased as a result.

It is also advantageous when a remaining sliver length of the sliver is predefined and the can change process is initiated as soon as the predefined remaining sliver length has been attained. The specification of a defined remaining sliver length contributes to avoiding the situation in which the sliver cans are completely emptied and to avoiding premature sliver can changes.

For this purpose, a remaining sliver length of the sliver at which an automatic can change process is to be initiated is advantageously pre-defined in the control unit.

It is also advantageous when the spinning station includes a measuring device, by means of which the remaining sliver length of the sliver is ascertainable. The measuring device is in control connection with the control unit, in order to initiate the automatic can change process.

According to one enhanced embodiment of the method, it is advantageous when the sliver is unthreaded by means of at least one handling device of the spinning machine. As a result, the sliver can be advantageously separated from the spinning machine already before an operator or a can changer arrives.

With respect to the spinning machine, the spinning machine and/or the spinning station advantageously include(s), for this purpose, at least one handling device for unthreading the sliver from a sliver guide of the spinning station. The handling device can be arranged, for example, at the spinning machine, in particular at a single spinning station, and, as a result, can advantageously unthread the sliver directly after the sliver has been returned. A handling device that serves multiple spinning stations and is arranged in the area of a spinning station is also conceivable. It is also possible, however, that the spinning machine includes a movable service unit, at which the at least one handling device is mounted. As a result, the handling device of the movable service unit can preferably also unthread the sliver from the sliver guide before a movable can changer arrives.

According to another enhanced embodiment of the method, it is advantageous when the sliver is unthreaded by means of at least one handling device of a movable can changer. A can changer, which is also provided, includes, for this purpose, a handling device, for example, a clamp for the sliver, for unthreading a separated sliver from the sliver guide. As a result, the spinning machine does not require handling devices that are specific to a spinning station or arranged in a movable service unit and, thus, can be designed to be simpler and more cost-effective. Only a single handling device is necessary at the movable can changer.

It is also conceivable that the at least one handling device of the spinning machine cooperates with the at least one handling device of the can changer in order to carry out the unthreading. This is conceivable for a handling device arranged in a movable service unit and for a spinning station-specific handling device. Two handling devices arranged at the spinning machine could also cooperate. For example, a handling device in the movable service unit could perform the unthreading process jointly with the handling device at the spinning station.

As described above, it is advantageous when the sliver is unthreaded already before the can change process is carried out. This is advantageous, in particular, when the unthreading is carried out by means of a handling device of the spinning machine, since, as a result, the actual can change process can be started immediately after the can changer arrives and can be carried out faster.

According to another advantageous enhanced embodiment, the sliver is unthreaded during the can change process. This is advantageous, in particular, when the unthreading is carried out by a handling device of the can changer, since this requires no additional time and the downtimes of the spinning stations can be kept low. It can be advantageous to unthread the sliver only during the can change process also when unthreading the sliver by means of a handling device of the spinning machine. The can change process can also be carried out without delay in this case.

In principle, it is also conceivable, however, to unthread the sliver from the sliver guide only after the actual can change has been carried out, in particular when the handling device is arranged at the can changer.

If the handling device is provided at the can changer, it is particularly advantageous when the sliver is clamped by a can gripper of the can changer to unthread the sliver from the sliver guide. As a result, the sliver can be advantageously unthreaded from the sliver guide by removing the sliver can from the spinning station. For this purpose, advantageously, with respect to the can changer, a clamp is arranged at a can gripper of the can changer or the can gripper itself forms a clamp.

It is particularly advantageous when the sliver is clamped by the can gripper at the sliver can to be removed and is pulled out of the sliver guide due to the removal of the sliver can.

BRIEF DESCRIPTION OF THE DRAWINGS

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

FIG. 1 shows a schematic front view of a spinning machine;

FIG. 2 shows a schematic front view of a spinning station of a spinning machine before the separation of the sliver;

FIG. 3 shows the spinning station from FIG. 2 after the separation of the sliver;

FIG. 4 shows a schematic front view of a spinning station that includes a handling device for unthreading the sliver after the separation of the sliver;

FIG. 5 shows the spinning station from FIG. 4 after the unthreading of the sliver;

FIG. 6 shows a section of a spinning machine with a movable service unit that includes a handling device for unthreading the sliver;

FIG. 7 shows a schematic side view of a spinning station that includes a can changer according to a first embodiment before an automatic can change process is carried out;

FIG. 8 shows the spinning station from FIG. 7 during the automatic can change process;

FIG. 9 shows a schematic side view of a spinning station that includes a can changer according to a second embodiment before an automatic can change process is carried out;

FIG. 10 shows the spinning station from FIG. 9 during the automatic can change process;

FIG. 11 shows a schematic side view of a spinning station that includes a can changer according to a third embodiment before an automatic can change process is carried out; and

FIG. 12 shows the spinning station from FIG. 11 during the automatic can change process.

DETAILED DESCRIPTION

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

In the following description of the exemplary embodiments, features that are identical or at least comparable with respect to their design and/or mode of operation are provided with identical reference characters. Moreover, these are explained in detail only at their first mention, while only the differences from the previously described exemplary embodiments are discussed in the subsequent exemplary embodiments. Moreover, for the sake of clarity, often only one or only a few of several identical components and/or features is/are labeled.

FIG. 1 shows a schematic front view of a spinning machine 1 that includes a plurality of adjacently arranged spinning stations 2. The spinning stations 2 are arranged, in the usual way, between two frames 11 on one or also on both longitudinal side(s) of the spinning machine 1. Each of the spinning stations 2 includes, in the usual way, a supply device 5, by means of which a sliver 4 is delivered out of a sliver can 3 to a spinning device 6. The sliver cans 3 are placed underneath the spinning stations 2 in one row or also in multiple rows. By means of the spinning device 6, a yarn 8 is spun out of the sliver 4, the yarn 8 also being wound, as known, onto a bobbin 7 by means of a winding device. The sliver 4, after exiting the sliver can 3 and before reaching the supply device 5, is guided through a sliver guide 9 at the spinning station 2, the sliver guide 9 being arranged underneath the supply device 5 in the present example. In the spinning machine 1 shown, a measuring device 17 is also arranged at each spinning station 2, by means of which a remaining length of the sliver 4 still located in the particular sliver can 3 can be ascertained. This can be carried out, for example, indirectly, by measuring the running length of the sliver 4 that has already been processed.

In the present example, the spinning machine 1 also includes a movable service unit 12, which can carry out maintenance operations, such as, for example, bobbin changes, cleaning processes, or, depending on the design of the spinning machine 1, spinning start-up processes as well. The spinning stations 2 of the spinning machine 1 can preferably also be designed as at least semi-autonomous spinning stations 2, however, which can then automatically carry out at least one spinning start-up process. The spinning stations 2 can also be designed to be fully autonomous, and so a movable service unit 12 is not absolutely necessary.

The spinning machine also includes at least one control unit 16 for controlling the spinning stations 2 and, possibly, the movable service unit 12. In the present case, a control unit 16 is apparent as a central machine control system of the spinning machine 1. Control units 16 can additionally also be provided at the spinning stations 2, however, in order to control the working elements of the spinning stations, for example, the measuring device 17, the supply device 5, the spinning device 6, and others. Each spinning station 2 can include a separate control unit 16 as a workstation control system or one control unit 16 can be provided as a workstation control system for a group of spinning stations 2.

The spinning machine 1 can be designed as a rotor spinning machine, and so a feeder is provided as a supply device 5. The spinning machine 1 could also be designed as an air-jet spinning machine, however, wherein the supply device 5 would then be designed as a drafting system.

FIG. 2 shows a method for separating a sliver 4 delivered out of a sliver can 3 at a spinning station 2, using the example of a workstation 2 at a rotor spinning machine. The sliver 4 is guided through the sliver guide 9 before the sliver 4 reaches the supply device 5 and is fed by the supply device 5 to the opening device 19. The supply device 5 is designed as a feeder in the present case and includes a feed roller 21 and a feed trough 20, between which the sliver 4 is clamped. The feed roller 21 is driven in the regular direction of rotation of the feed roller 21 during the production operation, as the result of which the sliver 4 is fed to the opening roller 19 in the delivery direction LR. The sliver 4 is opened into individual fibers by the opening roller 19, the individual fibers then being fed to the spinning device 6.

If the sliver 4 is now to be separated at the spinning station 2, the spinning station 2 is initially stopped. This can be carried out, for example, by stopping the feed roller 21, resulting in a thread break. It is also possible, however, to shut down the working elements of the spinning station 2 in a controlled manner. For this purpose, the control unit 16 of the spinning machine 1 and/or of the spinning station 2 is in control connection, among other things, with the spinning device 6 and with the supply device 5, as indicated by the dashed lines. The spinning station 2 is now stopped, but the sliver end 10 (see FIG. 3) of the sliver 4 is still clamped in the supply device 5, however. In order to separate the sliver 4, the supply device 5, namely the feed roller 21 in this case, is now briefly driven counter to the regular direction of rotation of the supply device 5, as indicated by the arrow.

As shown in FIG. 3, as a result, the sliver 4 is returned counter to the delivery direction LR until the sliver end 10 has been conveyed out of the supply device 5 and the clamping in the supply device 5 has been released. The sliver end 10 is now free and can be removed from the sliver guide 9, for example, within the scope of a can change process.

As already indicated in conjunction with FIG. 1, the separation of the sliver 4 can take place due to the attainment of a remaining length predefined in the control unit 16, the remaining length being detected by a measuring device 17 (not represented here), which, for this purpose, is also connected to the control unit 16. This can also take place, however, due to a signal predefined by a control unit 16, for example, within the scope of a lot change, or can also be triggered manually by an operator. In any case, when the sliver 4 is separated by means of a return, no sliver residue is spun, and so defective places in the yarn 8 are avoided. Thereafter, if the sliver 4 is to be unthreaded from the sliver guide 9, for example, within the scope of an automatic can change process or also for cleaning purposes, multiple possibilities are conceivable according to the method.

According to a first variant of the method and of the corresponding spinning machine 1, which is described with reference to FIGS. 4 and 5, the sliver 4 is removed from the sliver guide 9 by means of a spinning station-specific handling device 13. The handling device 13 is designed as a swivelable clamp 18 in this case. As soon as the return of the sliver 4 has ended and the sliver end 10 is free, the clamp 18 can be actuated by the control unit 16 and the sliver 4 can be clamped. Thereafter, the sliver end 10 is unthreaded from the sliver guide 9 by swiveling (see arrow in FIG. 4) the handling device 13.

This condition is shown in FIG. 5. Once the sliver 4 has been completely separated from the spinning station 2, the clamp 18 can be released so that the sliver 4 automatically drops into the sliver can 3 due to gravity. Alternatively, the handling device 13 can also be designed, however, such that the handling device 13 places the sliver 4 with the sliver end 10 directly in the sliver can 3.

According to a second variant of the method and of the corresponding spinning machine 1, the handling device 13 is arranged in a movable service unit 12. This is represented in FIG. 6. The handling device 13 is designed as a swivelable clamp 18 in the present case as well. In order to actuate the clamp, the handling device 13 is preferably connected to a control unit 16 (not shown here) of the service unit 12, which communicates with the control unit 16 of the spinning machine 1 and/or with the control unit 16 of the workstation 2. Furthermore, the unthreading can take place as described with reference to FIGS. 4 and 5.

The clamp 18 described in FIGS. 4 through 6 can be designed, of course, not only to be swivelable, but rather also movable in another way, in order to unthread the sliver 4 from the sliver guide 9. Moreover, the handling device 13 also does not absolutely need to include a clamp 18. A finger that is swivelable, or movable in any other way, into the path of the sliver 4 and deflects and, as a result, unthreads the sliver 4 is also conceivable. The unthreading of the sliver 4 can be carried out before, during, or after an automatic can change process, provided that a can changer 14 (see FIGS. 7 through 12) is still positioned at the spinning station 2.

FIGS. 7 and 8 show another embodiment of the method and of a movable can changer 14, in which the handling device 13 is arranged at the can changer 14. The can change process can be initiated, for example, as soon as the attainment of a predefined remaining sliver length has been registered by the measuring device 17. The desired remaining sliver length can be stored, for example, in the control unit 16 of the spinning machine 1 and/or of the spinning station 2. When the sliver cans 3 have been placed in multiple rows, however, a preventive can change of the sliver cans 3 of the other rows can also be carried out if a sliver can 3 has emptied in only one of the rows at the same standing area. A preventive can change after a certain operating time is also possible.

The can changer 14 is summoned for the automatic can change process, the can changer 14 carrying a full sliver can 3b. The can changer 14 also includes a can gripper 15 to handle the sliver cans 3 and exchange the sliver can 3a to be removed and replaced by the full sliver can 3b. In the representation shown in FIG. 7, the can changer 14 has become positioned in front of the relevant spinning station 2. The sliver 4 has already been separated at the relevant spinning station 2 due to the return carried out by means of the supply device 5 and is now connected to the spinning station 2 only at the sliver guide 9. In order to unthread the sliver 4, the handling device 13 is arranged at the can changer 14 directly at the can gripper 15 in the present case. The can gripper 15 includes a clamp 18, which clamps the sliver 4 underneath the sliver guide 9.

If, as represented in FIG. 8, the sliver can 3a to be removed is now removed by means of the can gripper 15, the sliver 4 is simultaneously unthreaded by means of the clamp 18 fastened at the can gripper 15 due to the movement of the can gripper 15.

FIGS. 9 and 10 show another embodiment of the method and of a movable can changer 14, in which the handling device 13 is arranged at the can changer 14. A clamp 18, as a handling device 13, is arranged directly at the can gripper 15. A situation is represented in FIG. 9, in which the sliver 4 has already been separated due to the return carried out by means of the supply device 5 and the can gripper 15 of the can changer 14 has just gripped the sliver can 3a to be removed. The sliver can 3a to be removed is now pulled out, to some extent, from its standing area underneath the spinning machine 1, as indicated by the arrow.

As soon as the can gripper 15, with the sliver can 3a, is located in the position represented in FIG. 10, in which the sliver can 3a is no longer located underneath, but rather in front of the spinning machine 1, the sliver 4 can be clamped by means of the clamp 18. In the present case, the sliver 4 is clamped directly at the front edge of the sliver can 3a to be removed. Due to the sliver can 3a being pulled out farther, the sliver 4 is also simultaneously unthreaded from the sliver guide 9. The sliver 4, more precisely, the sliver end 10, then remains outside of the sliver can 3a. In deviation from the embodiment shown, it is also possible, of course, to design the handling device 13 such that the handling device 13 places the sliver end 10 in the sliver can 3a.

FIGS. 11 and 12 show another embodiment of the method and of a movable can changer 14, in which the handling device 13 is arranged at the can changer 14. In this case, the handling device 13 includes a swivelable finger, which deflects the sliver 4 and, as a result, unthreads the sliver 4 from the sliver guide 9. FIG. 11 shows a situation in which the sliver can 3a to be removed has just been gripped by means of the can gripper 15.

FIG. 12 shows a situation, however, in which the sliver 4 has already been unthreaded from the sliver guide 9 by way of the finger of the handling device 13 having been swiveled.

The present invention is not limited to the represented and described exemplary embodiments. In deviation from the embodiments shown in FIGS. 7 through 12, a handling device 13 arranged at the can changer 14 could also include a swivelable clamp 18 similarly to FIGS. 4 through 6. Moreover, it would be conceivable to provide the handling device 13 at the can changer 14 separately from the can gripper 15. If the handling device 13 is provided at the can changer 14, it is also advantageous when the unthreading of the sliver 4 is carried out before or during the automatic can change process. It is also conceivable, however, to carry out the unthreading of the sliver 4 only after the actual can change process, as soon as the sliver can 3a has been accommodated on the can changer 14. Further modifications within the scope of the claims are also possible, as is any combination of the features, even if they are represented and described in different exemplary embodiments.

List of reference characters
1  spinning machine
2  spinning station
3  spinning station
   3a sliver can to be removed
   3b full sliver can
4  sliver
5  supply device
6  spinning device
7  bobbin
8  yarn
9  sliver guide
10 sliver end
11 frame
12 movable service unit
13 handling device
14 can changer
15 can gripper
16 control unit
17 measuring device
18 clamp
19 opening roller
20 feed trough
21 feed roller
LR delivery direction

Claims

1–16. (canceled)

17. A method for separating a sliver delivered out of a sliver can at a spinning station of a spinning machine, comprising:

delivering the sliver out of the sliver can with a supply device at the spinning station in a delivery direction to a spinning device;

with a sliver guide, guiding the sliver between the sliver can and the supply device;

clamping the sliver in the supply device at the spinning station; and

in order to separate the sliver, driving the supply device counter to the delivery direction, wherein the sliver is returned by the supply device and, as a result, the clamping of the sliver in the supply device is released.

18. The method according to claim 17, wherein, after the separation of the sliver, the sliver is unthreaded from the sliver guide of the spinning station.

19. The method according to claim 17, wherein the separation of the sliver takes place during an automatic can change process at the spinning station.

20. The method according to claim 17, further comprising pre-defining a remaining length of the sliver to be left in the sliver can, wherein the can change process is initiated when the predefined remaining sliver length has been reached.

21. The method according to claim 18, wherein the sliver is unthreaded by a handling device configured with the spinning machine.

22. The method according to claim 18, wherein the sliver is unthreaded by a handling device configured on a movable can changer.

23. The method according to claim 22, wherein the sliver is clamped by a can gripper of the can changer in order to unthread the sliver from the sliver guide.

24. The method according to claim 22, wherein the sliver is unthreaded from the sliver guide before a can change process.

25. The method according to claim 22, wherein the sliver is unthreaded during a can change process.

26. The method according to claim 17, wherein the sliver is clamped by a can gripper at the sliver can and is pulled out of the sliver guide upon removal of the sliver can from the spinning station.

27. A spinning machine, comprising:

a plurality of adjacently arranged spinning stations;

a row of sliver cans placed i underneath the spinning stations;

each of the spinning stations comprising a supply device that delivers a sliver out of one of the sliver cans at the spinning station, a spinning device, and a sliver guide in which the sliver is guided between the sliver can and the supply device;

a control unit configured to operate the spinning machine for: delivering the sliver out of the sliver can with the supply device at the spinning station in a delivery direction to the spinning device, wherein the sliver is guided by the sliver guide between the sliver can and the supply device; clamping the sliver in the supply device at the spinning station; and in order to separate the sliver, driving the supply device counter to the delivery direction, wherein the sliver is returned by the supply device and, as a result, the clamping of the sliver in the supply device is released.

28. The spinning machine according to claim 27, wherein the control unit defines a remaining sliver length of the sliver to remain in the sliver can at initiation of an automatic can change process.

29. The spinning machine according to claim 28, wherein each spinning station comprises a measuring device that determines when the remaining sliver length is reached.

30. The spinning machine according to claim 27, further comprising a handling device that unthreads the sliver from the sliver guide.

31. A movable can changer configured to carry out an automatic can change process at a spinning machine, comprising a handling device that is movable to a position to engage and unthread a separated sliver from a sliver guide at a spinning station of the spinning machine.

32. The movable can changer according to claim 31, wherein the handling device comprises a clamp.