Method for operating a ring spinning machine, maintenance device for a ring spinning machine and ring spinning machine

Abstract

In a maintenance device (14) for a ring spinning machine (1), which is designed to remove a spinning sleeve (4) at least temporarily from a working position (2) of the ring spinning machine (1) during a maintenance operation, wherein the maintenance device (14) has a gripper (15) for grasping the spinning sleeve (4), it is provided according to the invention that the gripper (15) has at least a first gripping section (16) and a second gripping section (17) for grasping the spinning sleeve (4), wherein the gripper (15) is designed to assume at least a first gripping position (18) and a second gripping position (19). A first inner diameter (22) defined by the first gripping section (16) in the first gripping position (18) corresponds essentially to a second inner diameter (24) defined by the second gripping section (17) in the second gripping position (19).

Description

TECHNICAL FIELD

[0001] The present invention relates to a method for operating a ring spinning machine, wherein spun yarn is wound onto a spinning tube at at least one workstation of the ring spinning machine, and wherein the spinning tube is at least temporarily removed from the workstation by a gripper during a maintenance operation. The invention also relates to a maintenance device for a ring spinning machine, which is designed to at least temporarily remove a spinning tube from a workstation of the ring spinning machine during a maintenance operation, wherein the maintenance device has a gripper for gripping the spinning tube. Furthermore, the invention relates to a ring spinning machine with at least one workstation designed to wind a spun yarn onto a spinning tube, and with a maintenance device. TECHNOLOGICAL BACKGROUND

[0002] Ring spinning machines have been around for a long time. In these machines, a roving coming from a drafting system is given a twist by the rotation of a ring traveller around a spinning tube. The resulting yarn is wound directly onto the spinning tube. The spinning tube is in a spinning position. This process usually takes place at numerous work stations on the ring spinning machine. If a yarn break occurs at one of the work stations, the spinning process must be interrupted at that work station. In order to continue the spinning process, the yarn end that has run up onto the spinning tube must be searched for and reattached to the roving. It is now possible to carry out this maintenance process automatically at individual work stations on the ring spinning machine. For this purpose, a work station where a yarn break has occurred is approached, for example by a mobile maintenance unit.To search for the end of the yarn, the spinning tube is removed from the spinning position and from the work station, for example by a gripper of the maintenance device.

[0003] Such a gripper is known, for example, from DE 41 22 780 A1. This gripper can be adjusted to various nominal diameters of fiber yarn carriers by means of a stationary clamping element. Other prior art grippers are also known from FR 2 561 674 A1 and CN 201 257 669 Y. PRESENTATION OF THE INVENTION

[0004] One problem with the described maintenance procedure is that the spinning tube or a ring rail on which the ring traveler is mounted are located at different heights during the spinning process to ensure even winding of the spinning tube with the yarn. Therefore, the space available for gripping the spinning tube or access to the spinning tube may be severely restricted, especially above the spinning tube, for example, due to balloon constriction rings. Furthermore, the space above the spinning tube may be restricted by the drafting system.

[0005] The present invention therefore has the object of proposing a method and devices which make it possible to remove a spinning tube from a work station of a ring spinning machine even in cases where space and accessibility are very limited.

[0006] The problem is solved by a method, a maintenance device and a ring spinning machine having the features of the independent patent claims.

[0007] In the method for operating a ring spinning machine, spun yarn is wound onto a spinning tube at at least one workstation of the ring spinning machine, and the spinning tube is at least temporarily removed from the workstation by a gripper during a maintenance operation. According to the invention, during the maintenance operation, the spinning tube is first gripped at a spinning position by a first gripping section of the gripper, moved to an intermediate position within the workstation, and then gripped by a second gripping section of the gripper and removed from the workstation.

[0008] The gripper's ability to grasp the spinning tube allows the entire removal process from the work station to be carried out in a smaller space. The first gripping section of the gripper can, for example, be located below the second gripping section during maintenance or removal. The spinning tube can therefore initially be grasped from above by the first gripping section and then lifted out of the spinning position. Since, as already explained, the free space above the spinning tube can be limited, the spinning tube is only moved upwards, for example by the first gripping section, within the scope of the available free space. Once this free space has been exhausted, the gripper's grasping action follows. In this case, the spinning tube is initially released by the first gripping section. The spinning tube is in the intermediate position and is fixed there if necessary.The gripper now moves downwards and grasps the spinning tube using the second gripping section. This creates free space above the spinning tube and the gripper, which can be used to remove the spinning tube from the work area.

[0009] According to the invention, the gripper assumes a first gripping position for gripping the spinning tube at the spinning position and a second gripping position for gripping the spinning tube at the intermediate position.

[0010] The gripper position here refers to the opening of the gripper, for example, an opening angle or a distance between two gripper arms. The geometry of the gripper and the relationship between the first gripper position and the second gripper position are selected in particular such that when the spinning tube is gripped by the second gripping section, a surface or a yarn on the surface of the spinning tube is not touched by the first gripping section. This can prevent damage to the yarn wound on the surface of the spinning tube.

[0011] The two gripper positions can result, for example, from the geometries of the first gripping section and the second gripping section, as well as the diameter of the spinning tube section to be gripped. The first gripper position is assumed, for example, when the spinning tube section is enclosed by the first gripping section, and the second gripper position is assumed, for example, when the spinning tube section is enclosed by the second gripping section. Depending on the gripper drive type, the various gripper positions can also be determined, for example, by the travel path of one or more motors.

[0012] It is also according to the invention if a first inner diameter defined by the first gripping section in the first gripper position substantially corresponds to a second inner diameter defined by the second gripping section in the second gripper position. This ensures that the spinning tube can be securely gripped by both gripping sections and in both gripper positions. The first inner diameter and the second inner diameter correspond, for example, to the aforementioned diameter of the spinning tube section to be gripped. The spinning tube section corresponds, for example, to an upper end of the spinning tube that is not wound with a yarn. The spinning tube section to be gripped can, for example, be conical.If the gripper grips the spinning tube with the first gripping section and the second gripping section at slightly different locations on the spinning tube section, the first inner diameter and the second inner diameter may differ slightly from each other.

[0013] It is also advantageous if the gripper grasps the spinning sleeve through a balloon constriction ring and moves it from the spinning position to the intermediate position. This allows the balloon constriction ring to be positioned anywhere on the work site. Furthermore, the balloon constriction ring does not have to be removed during maintenance. The balloon constriction ring is located above the spinning sleeve, for example. The gripper therefore passes the balloon constriction ring from above and then grasps the spinning sleeve using the first gripping section. The gripper does not have to pass completely through the balloon constriction ring. It is conceivable that only the part of the gripper reaches through the balloon constriction ring that contains the first gripping section. In the intermediate position, the spinning sleeve can, for example, extend at least partially through the balloon constriction ring.It is also advantageous if the gripper assumes a third gripping position for passing the balloon constriction ring. This can prevent damage to the balloon constriction ring during the maintenance process. To this end, it must be ensured that the extension or outer diameter of the gripper or the section of the gripper that passes the balloon constriction ring in the horizontal direction in the third gripping position is smaller than the diameter of the balloon constriction ring. For example, an opening angle or a distance between two gripper legs of the gripper is larger in the third gripping position than in the first gripping position but smaller than in the second gripping position.

[0014] It is also advantageous if the maximum opening of the gripper is limited to the third gripper position immediately before and during passage of the balloon constriction ring by a locking device or a control of an electric drive of the gripper. This can additionally ensure that the balloon constriction ring is not damaged during the maintenance process. The locking device can limit the opening of the gripper, in particular mechanically. This is particularly advantageous in the case of a continuously variable drive gripper, for example a pneumatic drive. The locking device can also be driven pneumatically, for example. If the gripper is electrically driven, for example by a stepper motor, various positions of the gripper can be specified by the control.In this case, an additional locking device may not be necessary.

[0015] It is advantageous if the first inner diameter in the third gripper position is larger than the first inner diameter in the first gripper position but smaller than the first inner diameter in the second gripper position and / or the second inner diameter in the third gripper position is larger than the second inner diameter in the first gripper position but smaller than the second inner diameter in the second gripper position. This ensures that the gripper does not damage the balloon constriction ring by assuming the third gripper position, but is nevertheless able to grip the spinning tube by means of the first gripping section by assuming the first gripper position. As already described, the first inner diameter in the first gripper position and the second inner diameter in the second gripper position correspond in particular to the diameter of a spinning tube section to be gripped.

[0016] It is also advantageous if the intermediate position is located vertically above the spinning position. The movement sequence that the gripper and the spinning tube must perform during the maintenance process is particularly simple. For example, the spinning tube can be held at least partially in the intermediate position by a spindle. In the intermediate position, the spinning tube is at least partially still on the spindle. When the gripper is gripped, it only needs to perform a linear downward movement, in addition to an opening, for example, the gripper leg.

[0017] It is advantageous if the spinning tube is held in the intermediate position by at least one spring pin of the spindle. In particular, the spinning tube remains in contact with the spindle and / or the at least one spring pin in the intermediate position. In this way, the spinning tube is fixed in the intermediate position and cannot perform any undesired movements when the gripper is gripping. As a rule, the spinning tube is also fixed during the spinning process by at least one spring pin or by a spring cap comprising several spring pins. The spring pins or the spring cap press against the spinning tube from the inside under spring tension and fix it on the spindle. The spring pins or the spring cap are arranged, for example, in the region of an upper end of the spindle. The same spring pins orThe same spring cap that fixes the spinning tube during the spinning process can also be used to fix the spinning tube in the intermediate position.

[0018] After the spinning tube has been removed from the workstation, a maintenance facility can, for example, search for a yarn end that has accumulated on the spinning tube. Once the yarn end has been located, the spinning tube can be returned to the workstation and moved into the spinning position. It is also conceivable that a new spinning tube could be fed to the workstation and moved into the spinning position. The previously described process can be carried out in reverse order of the process steps.

[0019] The maintenance device according to the invention for a ring spinning machine is designed to at least temporarily remove a spinning tube from a work station of the ring spinning machine during a maintenance process and has a gripper for gripping the spinning tube. It is proposed that the gripper has at least a first gripping section and a second gripping section for gripping the spinning tube, wherein the gripper is designed to assume at least a first gripping position and, by gripping around, a second gripping position, wherein a first inner diameter defined by the first gripping section in the first gripping position substantially corresponds to a second inner diameter defined by the second gripping section in the second gripping position. The maintenance device is thus designed in particular to carry out the method described above.The maintenance device therefore enables the spinning tube to be removed from the spinning position and the work station of the ring spinning machine even when space is limited in the area of the spinning tube.

[0020] As previously described, the gripper initially grips the spinning tube, for example an upper section of the spinning tube, using the first gripping section in the first gripping position. The gripper then moves the spinning tube into an intermediate position. The free space above the spinning tube can be utilized by the gripper. The spinning tube is then released and the gripper can grip the spinning tube or the described upper section of the spinning tube using the second gripping section in the second gripping position. As a result of the gripper gripping around the spinning tube as described, a new free space is created above the spinning tube and the gripper, which can be used to remove the spinning tube from the work station. The first inner diameter and the second inner diameter correspond in particular to a diameter of a section of the spinning tube to be gripped.

[0021] When the maintenance device is used as intended, the first gripping section and the second gripping section are arranged at a distance from one another, in particular vertically. The gripping sections are preferably located one above the other. The gripper can, for example, comprise two gripper legs, which define an opening in the gripper through their relative movements. The gripper legs can, for example, each be arranged so as to be pivotable about an axis. It is also conceivable for the gripper legs to be arranged so as to be pivotable about a common axis. The first gripping section and the second gripping section are, in particular, arranged at a distance from one another in a direction that runs parallel to an axis about which the gripper legs are arranged so as to be pivotable.

[0022] As already mentioned, the spinning tube section to be gripped can, for example, be conical. If the gripper grasps the spinning tube with the first gripping section and the second gripping section at slightly different locations on the spinning tube section, the first inner diameter and the second inner diameter may differ slightly from each other.

[0023] It is also advantageous if the gripper is designed as a pneumatic gripper. This allows the gripper to be designed inexpensively and with low wear. A compressed air system already present on a ring spinning machine can also be used for the gripper in this case. The pressure exerted on the spinning tube by the gripper can be controlled very precisely. The first gripper position can be assumed, for example, by the pneumatic closing of the gripper and the gripping of the spinning tube by the first gripping section. Accordingly, the second gripper position can be assumed, for example, by the pneumatic closing of the gripper and the gripping of the spinning tube by the second gripping section. The gripper can, for example, have two gripper legs that are driven by a common pneumatic cylinder. Alternatively, it is also conceivable for the gripper to be driven by one or more electric motors or hydraulically.

[0024] It is also advantageous if the maintenance device comprises a locking device, in particular a pneumatic one, which is designed to limit the maximum opening of the gripper. The limitation of the locking device can, for example, define the third gripper position already described in connection with the method. The third gripper position can be used to move the gripper at least partially through a balloon constriction ring without damaging the balloon constriction ring. The locking device can, for example, have an extendable pin or pneumatic cylinder. In an extended state, this pin or pneumatic cylinder can, for example, limit the maximum movement of one or two gripper legs, either directly or by means of an additional stop piece. The stop piece can, for example, be designed as a mechanical extension of a gripper leg.

[0025] It is advantageous if the first gripping section and the second gripping section each have at least one and in particular three elastic dampers for gripping the spinning tube. On the one hand, this prevents damage to the spinning tube by the gripper. On the other hand, the hold of the spinning tube in the gripper can be improved. The dampers can, for example, be at least partially embedded in the gripper. The dampers can also be made of plastic or rubber, for example, and / or have a circular cross-section. A substantially rectangular cross-section, in particular with rounded corners, is also conceivable. The shape of the dampers can also correspond to a spherical segment.

[0026] The ring spinning machine according to the invention comprises at least one workstation designed to wind a spun yarn onto a spinning tube. Furthermore, the ring spinning machine comprises a maintenance device. It is proposed that the maintenance device be designed according to the preceding description. The described features can be implemented individually or in any combination. The ring spinning machine is also particularly designed to carry out the previously described method.

[0027] The advantages already described in connection with the method and the maintenance device are therefore also realized in the ring spinning machine according to the invention. In particular, the spinning tube can be removed from the work station even during the spinning process, regardless of the position of the ring rail or spindle rail, even when space is very limited above the spinning tube.

[0028] The ring spinning machine can, for example, have a plurality of work stations, which are arranged in particular next to one another. The spinning machine can also have work stations on multiple machine sides. It is therefore conceivable for the ring spinning machine to have multiple maintenance devices, as described above. The maintenance device(s) can be designed as mobile units, in particular patrolling along the work stations of the ring spinning machine. If a yarn breakage occurs at a work station, the nearest maintenance device is requested, for example, to search for a yarn end that has accumulated on the spinning tube of the work station. The maintenance device(s) can, in particular, also be designed to reattach the found yarn end to the roving.

[0029] It is advantageous for the ring spinning machine if the first inner diameter in the second gripper position is dimensioned such that the first gripping section in the second gripper position does not touch a surface of the spinning tube wound with the spun yarn. As already described, the first inner diameter means the inner diameter defined by the first gripping section. The aforementioned dimensioning of the first inner diameter in the second gripper position ensures that the yarn on the surface of the spinning tube is not damaged by the gripper. The gripper can, for example, be designed such that an inner surface of the gripper tapers conically from the first gripping section to the second gripping section. BRIEF EXPLANATIONS OF THE FIGURES

[0030] Further advantages of the invention are described in the following exemplary embodiments. It shows: Figure 1 shows a schematic side view of a work station of a ring spinning machine with a maintenance device, Figure 2 shows a first step of a maintenance process on the ring spinning machine in a schematic side view, Figure 3 shows a second step of a maintenance process on the ring spinning machine in a schematic side view, Figure 4 shows a third step of a maintenance process on the ring spinning machine in a schematic side view, Figure 5 shows a fourth step of a maintenance process on the ring spinning machine in a schematic side view, and Figure 6 shows a gripper in various gripper positions in a schematic top view. WAYS OF IMPLEMENTING THE INVENTION

[0031] In the following description of the figures, the same reference numerals are used for identical and / or at least comparable features in the various figures. The individual features, their design, and / or mode of operation are usually only explained in detail when first mentioned. If individual features are not explained in detail again, their design and / or mode of operation correspond to the design and mode of operation of the features with the same or identical functions already described.

[0032] Figure 1shows a work station 2 of a ring spinning machine 1 according to the invention in a schematic side view. The work station 2 is designed to wind a spun yarn 3 onto a spinning tube 4. First, a fiber strand 5 is guided through a drafting system 6. The fiber strand 5 is then fed to a ring traveler 8, which is arranged on a ring rail 9 and there rotates on a ring 7 around the spinning tube 4. The yarn 3 thus produced is wound onto the spinning tube 4. For this purpose, the spinning tube 4 is placed on a spindle 10, which in turn is arranged on a spindle beam 11. The spinning tube 4 is in this spinning position 12 during the spinning process. Ballooning of the fiber strand 5 circulating around the spinning tube 4 is limited, for example, by a balloon constriction ring 13.

[0033] The ring spinning machine 1 comprises a maintenance device 14 designed to at least temporarily remove the spinning tube 4 from the work station 2 of the ring spinning machine 1 during a maintenance operation. For this purpose, the maintenance device 14 has a gripper 15. The features of the gripper 15 are discussed in more detail in the description of the following figures. A maintenance operation may occur if a yarn break occurs at the work station 2, thus requiring the spinning process to be interrupted. In this case, the spinning tube 4 must be removed by the maintenance device 14 from the spinning position 12 and the work station 2 in order to locate a yarn end that has accumulated on the spinning tube 4 for subsequent attachment of the yarn end to the fiber strand 5. The maintenance device 14 can be moved, for example, along the work stations 2 of the ring spinning machine 1, so that maintenance operations can be performed at various of the work stations 2.

[0034] Figure 2 shows a first step of such a maintenance process. In a schematic view, the area directly around the spinning tube 4 is shown. The spinning tube 4 is still in the spinning position 12 in this step. Due to a possibly very limited free space above the spinning tube 4, the spinning tube 4 is grasped by the gripper 15 through the balloon constriction ring 13. The gripper 15 has a first gripping section 16 and a second gripping section 17 for this purpose. The gripper 15 is also designed to assume a first gripping position 18 and a second gripping position 19. This is described in connection with the Figures 3 and 4 described in more detail. In the Figure 2 the gripper 15 is in a third gripper position 20. This gripper position is assumed so that the gripper 15 can pass the balloon constriction ring 13 without damaging the balloon constriction ring 13.

[0035] In this figure, the part of the spindle 10 onto which the spinning tube 4 is mounted is also shown in dashed lines. The spindle 10 comprises, for example, a spring pin 21 that fixes the spinning tube 4 during the spinning process. The spindle 10 can also comprise several spring pins 21, which are, for example, part of a spring cap. In the illustrated first step of the maintenance process, the gripper 15 passes the balloon constriction ring 13 in the third gripper position 20 in order to grip the spinning tube 4 from above. In the case of a movable ring rail 9 and / or a movable spindle beam 11, these are in particular not in a starting position since the yarn break to be repaired occurred, for example, in the middle of the spinning process.

[0036] The next step of the maintenance process is in Figure 3shown. The gripper 15 assumes the first gripper position 18 in order to grasp the spinning tube 4, or an upper end of the spinning tube 4, with the first gripping section 16. A first inner diameter 22 defined by the first gripping section 16 in the first gripper position 18 corresponds to an outer diameter of the spinning tube 4. The spinning tube 4 is then at least partially pulled upwards from the spindle 10 by the gripper 15. The spinning tube 4 is moved by the gripper 15 into an intermediate position 23.

[0037] In Figure 4 the spinning sleeve 4 is shown in the intermediate position 23. In the intermediate position 23, the spinning sleeve 4 is still fixed by the spring pin 21. Between the Figures 3 and 4The gripper 15 has performed a gripping operation not shown in detail. The gripper 15 now grasps the spinning tube 4 by means of the second gripping section 17 in the second gripper position 19. By gripping the gripper 15, additional space has been gained above the spinning tube 4, which is now available for further movements of the gripper 15. A second inner diameter 24 defined by the second gripping section 17 in this second gripper position 19 in turn corresponds to an outer diameter of the spinning tube 4. The first inner diameter 22 defined by the first gripping section 16 in the first gripper position 18 corresponds to the second inner diameter 24 defined by the second gripping section 17 in the second gripper position 19.

[0038] As can be seen from a comparison of the Figures 2, 3 and 4As is clear, the first inner diameter 22 in the third gripper position 20 is larger than the first inner diameter 22 in the first gripper position 18 but smaller than the first inner diameter 22 in the second gripper position 19. Likewise, the second inner diameter 24 in the third gripper position 20 is larger than the second inner diameter 24 in the first gripper position 18 but smaller than the second inner diameter 24 in the second gripper position 19.

[0039] In Figure 4 It can also be seen that the first inner diameter 22 in the second gripper position 19 is dimensioned such that the first gripping section 16 does not touch a surface 25 of the spinning tube 4 wound with the spun yarn 3.

[0040] In Figure 5The figure shows the spinning tube 4 being lifted out of the area of the balloon constriction ring 13 by the gripper 15. The spinning tube 4 can now be removed from the work station 2, after which the maintenance device 14 can search for the yarn end that has accumulated on the spinning tube 4. The spinning tube 4 can then be reinserted into the work station 2 and the spinning position 12 in the reverse order of the steps shown.

[0041] In Figure 6An embodiment of the described gripper 15 is shown in various gripper positions 18, 19, 20 in a schematic top view. In this example, the gripper 15 has two gripper legs 26. The respective gripper position 18, 19, 20 is formed by the relative position between the gripper legs 26. The first gripper position 18 is shown on the left, the second gripper position 19 in the middle, and the third gripper position 20 on the right. Due to the top view, only the second gripping section 17 is visible in this illustration. The second gripping section 17 comprises, for example, three elastic dampers 27, which, on the one hand, enable secure gripping of the spinning tube 4 and, on the other hand, prevent damage to the spinning tube 4. In this example, the gripper 15 is designed as a pneumatic gripper 15. The gripper 15 comprises two connections 28 for a compressed air system (not shown) of the ring spinning machine 1 or the maintenance device 14.A locking device 29 is arranged on the gripper 15 and is designed to limit a maximum opening of the gripper 15. In this example, "maximum opening" refers to a maximum distance or a maximum opening angle between the gripper legs 26. The locking device 29 is also pneumatic in this example, with a pneumatic cylinder 30 being moved by compressed air supplied via the connections 28.

[0042] In an extended position of the pneumatic cylinder 30, as shown on the right, for example, this prevents the gripper 15, possibly with the aid of an additional stop piece 31, from opening beyond the third gripper position 20. As previously described, in the third gripper position 20, the gripper 15 can pass the balloon constriction ring 13 without damage and then assume the first gripper position 18 to grasp the spinning tube 4. In this example, the stop piece 31 is designed as a mechanical extension of one of the two gripper legs 26.

[0043] The present invention is not limited to the illustrated and described embodiments. Modifications within the scope of the claims are also possible. LIST OF DESCRIPTIONS

[0044] 1 Ring spinning machine 2 Work station 3 Yarn 4 Spinning tube 5 Fiber bundle 6 Drafting system 7 Ring 8 Ring traveler 9 Ring rail 10 Spindle 11 Spindle beam 12 Spinning position 13 Balloon constriction ring 14 Maintenance device 15 Rapier 16 First gripping section 17 Second gripping section 18 First gripper position 19 Second gripper position 20 Third gripper position 21 Spring pin 22 First inner diameter 23 Intermediate position 24 Second inner diameter 25 Surface 26 Rapier leg 27 Damper 28 Connection 29 Locking device 30 Pneumatic cylinder 31 Stop piece

Claims

1. Method for operating a ring spinning machine (1), wherein yarn (3) spun on at least one workstation (2) of the ring spinning machine (1) is wound onto a spinning sleeve (4), and wherein the spinning sleeve (4) is at least temporarily removed from the workstation (2) by a gripper (15) during a maintenance operation, characterized in that during the maintenance operation, the spinning sleeve (4) is first gripped at a spinning position (12) by a first gripping portion (16) of the gripper (15), is brought to an intermediate position (23) within the workstation (2) and is subsequently gripped by a second gripping portion (17) of the gripper (15) and removed from the workstation (2) and that the gripper (15) assumes a first gripper position (18) for gripping the spinning sleeve (4) at the spinning position (12) and a second gripper position (19) for gripping the spinning sleeve (4) at the intermediate position (23) and that a first inner diameter (22), defined by the first gripping portion (16), in the first gripper position (18) substantially corresponds to a second inner diameter (24), defined by the second gripping portion (17), in the second gripper position (19).

2. Method according to the preceding claim, characterized in that the gripper (15) grips the spinning sleeve (4) through a balloon control ring (13) and moves it from the spinning position (12) into the intermediate position (23).

3. Method according to one of the preceding claims, characterized in that the gripper (15) assumes a third gripper position (20) for passing through the balloon control ring (13).

4. Method according to one of the preceding claims, characterized in that, directly before and during the passage through the balloon control ring (13), a maximum opening of the gripper (15) is restricted to the third gripper position (20) by a locking device (29) or a control of an electric drive of the gripper.

5. Method according to one of the preceding claims, characterized in that the first inner diameter (22) in the third gripper position (20) is larger than the first inner diameter (22) in the first gripper position (18) but smaller than the first inner diameter (22) in the second gripper position (19), and / or the second inner diameter (24) in the third gripper position (20) is larger than the second inner diameter (24) in the first gripper position (18) but smaller than the second inner diameter (24) in the second gripper position (19).

6. Method according to one of the preceding claims, characterized in that the intermediate position (23) is located above the spinning position (12) in the vertical direction.

7. Method according to one of the preceding claims, characterized in that the spinning sleeve (4) is held in the intermediate position (23) by at least one spring pin (21) of a spindle (10), wherein the spinning sleeve (4) in the intermediate position (23) in particular remains in contact with the spindle (10) and / or the at least one spring pin (21).

8. Maintenance device (14) for a ring spinning machine (1), which is designed to remove a spinning sleeve (4) at least temporarily from a workstation (2) of the ring spinning machine (1) during a maintenance operation, wherein the maintenance device (14) has a gripper (15) for gripping the spinning sleeve (4), characterized in that the gripper (15) has at least a first gripping portion (16) and a second gripping portion (17) for gripping the spinning sleeve (4), wherein the gripper (15) is designed to assume at least a first gripper position (18) and a second gripper position (19), wherein a first inner diameter (22), defined by the first gripping portion (16), in the first gripper position (18) substantially corresponds to a second inner diameter (24), defined by the second gripping portion (17), in the second gripper position (19).

9. Maintenance device (14) according to the preceding claim, characterized in that the gripper (15) is designed as a pneumatic gripper (15).

10. Maintenance device (14) according to one of the preceding claims, characterized by a locking device (29), which is in particular pneumatic and which is designed to restrict a maximum opening of the gripper (15).

11. Maintenance device (14) according to one of the preceding claims characterized in that the first gripping portion (16) and the second gripping portion (17) each have at least one and in particular three elastic dampers (27) for gripping the spinning sleeve (4).

12. Ring spinning machine (1) with at least one workstation (2), which is designed to wind a spun yarn (3) onto a spinning sleeve (4), and with a maintenance device (14), characterized in that the maintenance device (14) is designed according to one of claims 8 to 11.

13. Ring spinning machine (1) according to the preceding claim, characterized in that the first inner diameter (22) in the second gripper position (19) is dimensioned in such a way that the first gripping portion (16) in the second gripper position (19) does not touch a surface (25) of the spinning sleeve (4) onto which the spun yarn (3) has been wound.

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