EP0391110B1 - Method of, and device for, threading a thread being partially wound onto a bobbin in a spinning machine - Google Patents

Description

The invention relates to a method for threading a thread from a yarn carrier located at the spinning position of a ring spinning machine into a rotor according to the preamble of claim 1 and a device for carrying out the method using an operating robot according to claim 4. A method or a device of this type is known from GB-A-11 89 528. A yarn carrier is understood to mean an empty tube or an empty tube with a wound auxiliary thread or a tube with a package. The process and the operating robot can be e.g. Use to thread a thread or an auxiliary thread into the rotor and other thread guide elements during the repair of thread breaks during the spinning process and in connection with a robot-assisted piecing or unwinding after doffing on a ring spinning machine.

Some operating robots are known from the patent literature, which are designed to correct thread breaks on a ring spinning machine. Examples are found in U.S. Patent 3,445,997, DAS 1,760,259, DAS 2,501,338 and U.S. Patent 3,628,320. With all such robots, it is necessary to carry out certain work on the spindle of the processing position (spinning station). Such works include, for example, finding the end of the thread on the bobbin (the bobbin) carried by the spindle or winding an auxiliary thread on the bobbin, threading a thread into the rotor, etc. Then the free end of the thread with that coming from the drafting unit of the spinning machine Fiber stream connected and attached to this.

All known solutions only work from the "front", i.e. the robot normally runs along a machine side, which can be referred to as the "front" with respect to the corresponding row of spinning stations. If the robot has to work at a certain point, it positions itself first at this point and then extends working elements from the front into the spinning position. In such circumstances, it is almost impossible to make controlled movements of the working elements around the entire circumference of the spindle.

Various methods and devices are known for threading the yarn into the runner, e.g. as described in the aforementioned GB-A-11 89 528 or in CH-PS 515 172, using an air flow with which the rotor is brought into a specific position on the spinning ring, whereupon it is moved from the cop to the rotor track of the spinning ring is pushed onto the yarn. However, this principle, which is known per se, could not be implemented in practice with a reliability which meets today's requirements, so that the experts followed a number of other suggestions for threading a thread into the rotor of a ring spinning machine.

For example, in GB-A-11 89 528, the mouth of the retention memory is first moved into the end position and then a slider is pushed forward, which moves the stretched thread piece laterally from the yarn carrier via the spinning ring and then jerkily in the direction of the yarn carrier. The rotor is then pushed onto the piece of thread held over the edge of the spinning ring by means of an air jet. This jerky movement of the slide means that the piece of thread on the spinning ring cannot be scoured and the movement of the ring traveler on the edge of the spinning ring Tensioned thread piece can also (further) damage the thread piece, whereby breakage of the thread piece cannot be reliably avoided.

It is an object of the present invention to further develop the threading principle mentioned to the extent that it is suitable for practical use in connection with an operating robot.

This object is achieved by the characterizing features of claims 1 and 4. The advantage of this solution lies in the high precision of the thread guide, which is essentially a result of the controlled, precisely specified movement sequences during the manipulation of the thread, so that the threading takes place with the greatest reliability, e.g. following an automatically controlled winding process, in the course of which a piece of thread clamped on two sides is wound with high reliability at a point on the yarn carrier which can be determined as desired. Since this winding can also be carried out on an empty tube with the same high level of reliability, the subsequent threading method can be used not only after thread breaks, but also after doffing or after a batch change or when the ring spinning machine is started up. All of these processes run fully automatically when the method proposed here is supported by an operating robot. Operating personnel are no longer required for the actual work processes.

For the sake of completeness, reference should be made briefly to DE-A-23 61 969. Here, for threading the runner by means of a rod which can be pivoted downwards, the stretched and stretched thread piece in the region of the spinning ring, which extends between the yarn carrier and the mouthpiece of a retaining memory, is pressed down and the mouthpiece is then pressed moved along part of an elliptical path behind a rotor located on the spinning ring. The rod is then pivoted up again, as a result of which the piece of thread extending between the rod end and the mouthpiece is to be threaded into the fixed runner through its downward opening. This is not only complicated due to the interaction of the rod and the mouthpiece of the retention memory, but also leads to unnecessary chafing of the thread piece on the spinning ring and on the end of the wire-shaped rotor facing the spinning ring. A threading success that is sufficient for today's conditions cannot be achieved.

Overall, the measures presented here, based on the teaching of this proposal, result in unprecedented success in threading and a broader range of uses when starting up the machine, removing threads, doffing and changing lots, the aids used being simple in structure and being particularly good in an already proposed method for fully automatic winding of a thread, for example of an auxiliary thread.

The retention memory for the thread or its mouth is connected in particular as a thread guide element to a coordinate-controlled guide. Thanks to the combined storage and guiding function, the piece of thread stretched elastically between the retention memory and the thread carrier can be guided precisely, gently and in a computer-controlled manner that is gentle on the thread. This controlled guide is so universally applicable that it can be used to wind the piece of thread on the package or directly on the sleeve, for. B. doffing, also for threading the free end of the thread piece into the runner and for attaching the end of the thread piece to the fiber stream coming from the fuse is suitable. These manipulations can also be carried out one after the other without the thread end of the thread piece getting out of control and having to be searched again for one of the partial operations.

A particular advantage lies in the fact that the constant auxiliary thread length defined by the thread storage means that the piece of auxiliary thread used can be safely separated out by a cleaning cut in the automatic winder. This makes it possible to use a preferred auxiliary thread quality, which can even differ considerably from the quality of the spinning thread. The quality of the auxiliary thread can be optimally selected with regard to special requirements for individual process steps when winding, threading and / or attaching, without this having adverse effects on the uniform yarn quality of the product.

Details and further advantages of the invention are explained in more detail below on the basis of preferred exemplary embodiments with the aid of the drawings. The selected exemplary embodiments are intended to show the principle of the invention. The invention is not restricted to the embodiments described here.

Fig. 1

einen Bedienroboter mit einem Fadenspeicher, in Verbindung mit einer Ringspinnmaschine,

Fig. 2

eine Einfädelvorrichtung in Unteransicht,

Fig. 3

die perspektivische Prinzipdarstellung des Einfädelvorganges mit dem Gerät nach Fig. 2,

Fig. 4

Luftdüsen zur Positionierung des Läufers,

Fig. 5

den Fadenspeicher gemäss Fig. 1 als Hilfsmittel beim Anwickeln,

Fig. 6

den Fadenspeicher als elastische Rückhaltevorrichtung beim Anwickeln eines Hilfsfadens,

Obwohl die Erfindung im folgenden anhand eines Beispiels zum Einfädeln eines Hilfsfadens mit einem einen Hilfsfadenvorrat mitführenden Bedienroboter beschrieben wird, ist sie gleichermassen vorteilhaft in Verbindung mit einer direkten Erfassung des Spinnfadens vom Kops. Auf die hier beschriebene Weise lässt sich der Spinnfaden durch Manipulation des Bedienroboters ebenso vorteilhaft in Fadenführungselemente der Spinnmaschine einfädeln.The figures show schematically:

Fig. 1

an operating robot with a thread store in connection with a ring spinning machine,

Fig. 2

a threading device in bottom view,

Fig. 3

the perspective schematic representation of the threading process with the device of FIG. 2,

Fig. 4

Air nozzles for positioning the rotor,

Fig. 5

1 as an aid when winding,

Fig. 6

the thread storage device as an elastic retention device when winding an auxiliary thread,

Although the invention is described below using an example for threading an auxiliary thread with an operating robot carrying an auxiliary thread supply, it is equally advantageous in connection with a direct detection of the spinning thread from the cop. In the manner described here, the spinning thread can also be advantageously threaded into thread guiding elements of the spinning machine by manipulating the operating robot.

According to the preferred embodiment described, an operating robot 1 can be moved along a ring bench 2 of a spinning machine. Upon a corresponding signal, it automatically positions itself at a specific spinning position, for example to correct a broken thread or to Piecing. The robot is stored and guided via guide elements, for example guide rails 3 and 4, which are connected to the spinning machine. The robot contains, for example, a supply spool 5 for an auxiliary thread 6, a delivery mechanism 7 for pulling the auxiliary thread 6 from the supply spool 5, and a cutting device 9 for cutting a defined auxiliary thread piece 6.1 from the auxiliary thread supply.

In the robot 1 there is also a thread winding device, which can be adjusted in height in the Z direction, for example by means of a threaded spindle 13, and can be displaced horizontally in the X direction, for example by means of a linear drive 14. This allows parts of the thread winding device to be pushed, for example, laterally or axially over the thread tube 40 or over the thread body.
Furthermore, a thread store in the form of a suction pipe 15 is provided, which is connected by a hose 19 to a vacuum source 20. The suction pipe 15 is designed to receive a thread section of a certain length. The mouth 16 of the suction pipe 15 can be moved three-dimensionally under the influence of a program-controlled control 50, as is indicated by a servo axis 22 shown schematically in FIG. 1.

The controller 50 can be designed, for example, as an autonomous robot controller in the form of a processor-equipped programmable control device which ensures automatic operation.

The threading guide 12 is provided with a holder 26 for further components. A controllably rotatable ring 27 is mounted on the underside of the holder 26. The ring 27 is connected to a controllable drive 34. 2, the ring 27 is provided with a feedthrough 29. The bushing 29 is dimensioned such that the ring 27 can be pushed laterally over the thread tube 40 or over the thread body. However, the ring can also be closed and can be guided axially on or around the yarn tube 40.

The entire bracket 26 can be moved under the action of the drive 14 in the X direction e.g. Move linearly between the ring bank 3 and the thread balloon ring 41 towards the sleeve 40 and slide with the ring opening 29 over the sleeve until the ring 27 is coaxial with the axis of rotation of the sleeve 40. By activating the drive 34, the ring 27 is caused to rotate a defined distance along the spinning ring 23.

In the example, a small brush 31 is placed on the underside of the ring 27, which serves to move the rotor along the circumference of the ring 27, for example in order to temporarily keep the rotor out of a certain area of the ring, or also to hold the rotor during the process described later Threading process to slide over the thread.

Alternatively, one or more blowing nozzles 32 according to FIG. 4 can be attached to the holder 26, which are provided with an air supply and can be activated in a controlled manner. They direct their blow jet approximately tangentially to the spinning ring 23 in order to temporarily fix the rotor 24 on the opposite side of the spinning ring 23 when the compressed air is activated. E.g. two blowing nozzles 32A and 32B act on the spinning ring 23 in different directions of rotation. An air blast blows the runner outside the working area of the thread guide 25, while a time-controlled counter air blast positions the runner on the opposite side of the threading device.

A slide 28 is attached to the holder 26 and can be displaced in the X direction under the influence of a drive 37, for example a pneumatic drive. The slide sits on the holder 26 off-center, so that its main axis leads into the peripheral region of the sleeve 40 according to FIG. 3, preferably approximately tangentially to the spinning ring 23, so that its tip can be easily positioned over the upper sliding surface of the spinning ring 23. The slider 28 serves for the exact positioning of the thread during the threading into the runner described later by pushing the runner onto the thread.

As a preparatory step for the winding or threading process of the robot 1, e.g. an auxiliary thread piece 6.1 of a certain length, e.g. about 150 cm, sucked into the tube of the thread store 15. This is done by activating the delivery mechanism 7 with a specific positioning of the thread store 15, e.g. in position P.1 according to Fig. 5. By means of suitable control means the delivery mechanism 7 is switched off as soon as the desired auxiliary thread length is in the tube of the thread store 15, e.g. when the auxiliary thread start 6.3 reaches a thread sensor 36 at the rear area of the thread store 15.

As mentioned, the thread store 15, in the example its mouth 16, can be manipulated three-dimensionally under the influence of a servo control. In the example according to FIG. 5, which shows the further program-controlled sequence when the thread is wound onto the cop or onto the empty sleeve 40, the mouth 16 of the thread store 15 subsequently makes a pendulum movement in the inner region of a winding ring 27, for example along the one in FIG 5 indicated path 39 in position P.2. The auxiliary thread is placed on a clamping device 35 on the underside of the winding ring 27. The mouth 16 of the thread store 15 is then moved back again, around the clamping device 35, into the starting position P.1, the auxiliary thread 6 being clamped in by the clamping device. Now the cutting device 9 separates the auxiliary thread 6 from the feed, so that a finite auxiliary thread piece 6.1 of a defined length is produced. In the further course of the process, this known auxiliary thread length is used, as a result of which different process steps can be better planned in advance and are associated with fewer uncertainties when processing the control programs.

The auxiliary thread start 6.3 is still in the position of the sensor 36 within the thread store 15. The thread is held in the thread store 15 by the suction effect with a slight pull relative to the clamping device 35. With the mouth 16 of the thread store 15, the controlled guidance of the auxiliary thread elastically retained in the thread store now takes place.

The mouth 16 of the thread store 15 with the auxiliary thread piece is now servo-controlled in a lower winding position P.4, e.g. performed within the range of the ring bench movement, as shown schematically in Fig. 6. The ring 27 is caused to rotate a defined number of times so that it winds the auxiliary thread end 6.2 held on the clamping device 35 around the sleeve 40 or around its package 43. During this winding process, the auxiliary thread is increasingly pulled out of the elastic retaining thread store 15.

After taking over a certain length of auxiliary thread from the thread store 15, the sleeve 40 is braked to a standstill by means of a spindle brake, so that on the one hand the remaining auxiliary thread length is guaranteed to remain in the thread store 15 and on the other hand the wound end of the auxiliary thread 6.2 cannot be pulled off the package, e.g. in a subsequent threading process.

In the processes described, auxiliary thread start and end are held by components whose positions are clearly determined. The auxiliary thread that is elastically clamped between two "grippers" can be manipulated three-dimensionally in this way, so that the winding location on the sleeve 40, furthermore the type of winding formation and also the length of the auxiliary thread to be wound from the operating device, for example can be controlled by program specifications. Under these conditions, winding is ensured with high reliability. The winding process is controlled with the help of the thread storage device in a clearly defined movement sequence, which is no longer influenced by coincidences, as was the case, for example, when blowing a free auxiliary thread end onto the package according to the prior art.

Following the winding-up process, the operating robot 1 can feed the auxiliary thread start 6.3 from the thread store 15 to the spinning station or the various thread guide elements, thread it into thread guide elements and finally attach it to the current fiber stream. A corresponding example for threading is shown below in connection with the schematic representation in FIG. 3.

For the further description it is assumed that a thread piece 6.1 with one end already lies on the sleeve 40 and is held thereon. The other end 6.3 of the thread piece 6.1 is located in the suction pipe 15, where it is retained by the suction effect exerted by the vacuum source 20, so that the outer, free thread piece between the mouth 16 of the suction pipe 15 and the sleeve 40 is kept constantly under slight tension .

To prepare the following method steps, the sleeve 40 is removed by suitable measures, for example by actuating a spindle brake, which is not shown in detail in the figures, braked to a standstill. Now the holder 26 is moved by activating the drive 14 in the above-mentioned manner in the X direction towards the sleeve 40 and pushed with its opening 29 over the sleeve 40, so that the ring 27 is now coaxial with the sleeve 40.

By activating the rotary drive 34, the ring 27 and with it the brush 31 are rotated around the sleeve 40 to such an extent that the brush 31 pushes the rotor 24 out of the working area of the slide 28. Thereafter, the holder 26 with the slide 28 located thereon is pushed back into the starting position outside the sleeve 40. Alternatively, the blowing nozzles 32 can also be activated for the same purpose instead of the rotary drive.

In a next method step, the slide 28 is extended, for example by the slide drive 37, into the working position according to FIG. 3, just above the effective area of the now free spinning ring 23. During this manipulation, the mouth of the suction pipe 15 assumes position A according to FIG. 3. With a notch 25 attached to its front rod end, the slider 28 engages in the thread piece 6.1. The notch 25 is designed and adapted to the surface of the spinning ring in such a way that it holds the thread in the respective position on the one hand and protects it on the other hand, so that the brush 31 does not damage, strip or take away the thread when it moves the rotor 24 can.

Subsequently, the suction tube 15 is guided with the thread piece 6.1 over the slide 28 and lowered with its mouth 16 into a position B which is lower than that of the slide 28. The tensioned thread piece 6.1 is located at a certain radial distance from the spinning ring 23. The in this way, part of the thread 6.1 clamped between the notch 25 and the mouth 16 of the suction pipe 15 is thus directed obliquely downwards. In these manipulations, the thread 6 is pulled out of the elastically restrained suction pipe 15, if necessary, so that it remains taut throughout the entire course of movement.

3, the suction pipe 15 is now moved into the position C, so that the thread 6.1 is tangent to the spinning ring 23 and still runs downward from the notch 25 to the mouth 16 of the suction pipe 15. The tangential direction is inclined by an angle "alpha" with respect to the plane of the spinning ring 23, as indicated in FIG. 3. In the example, the value of "alpha" can be approximately 10 degrees.

In the following phase, the holder 26 or the threading guide 12 is moved to the sleeve 40 by the drive 14, so that the ring 27 is again coaxial with the spinning ring 23 and the sleeve 40. The Z position is selected in a program-controlled manner such that the threading guide 12 is coupled to the holder 26 on the ring bench 3 according to FIG. 1, so that the holder 26 follows the lifting movements of the ring bench 3. By pressing the Rotary drive 34 for the ring 27, the brush 31 on the spinning ring 23 is rotated clockwise in the example shown in FIG. 3, whereby it pushes the rotor 24 over the thread piece 6.1 lying obliquely downwards on the spinning ring 23 and thus the actual threading process of the thread in takes the runner. The slide 28 and its holder 26 are then retracted into their starting positions. The entire device is uncoupled from the moving ring bench 3.

The operating robot 1 can then be used to thread the part of the thread piece 6.1 remaining in the suction pipe 15 into other thread guide elements in a similar manner by corresponding program-controlled manipulations. Finally, the thread beginning 6.3 is attached to the current fiber stream. This last step is no longer part of the actual threading and is not described further here.

As mentioned, the suction pipe 15 acts as a thread store in the context described. It brings about an elastic retention of the thread against the tensile force emanating from the braked sleeve 40. However, the thread storage device does not have to be designed as a suction tube, but it can also have any other configuration that is suitable for the elastically yielding retention of a piece of thread.

Even during threading, as in the winding described above, the thread to be threaded is held by components whose positions are clearly determined during each phase of the process. The threading is thus controlled in a clearly defined movement sequence, which is no longer influenced by randomness and uncertainties, as was the case with known proposed solutions according to the prior art. In this application, too, the manipulable thread store achieves significantly improved reliability as a prerequisite for a fully automatic process sequence.

In the example, the described method steps are triggered and coordinated by a central process control, in the example by a processor-equipped programmable control device, which is housed in the operating robot and ensures automatic operation. Certain sub-processes, such as synchronization with processes on the spinning machine or the triggering of machine-specific spindle brakes, are coordinated and controlled via interfaces to the machine control. However, other suitable forms of sequence control can also be implemented. The sequence of the method steps described is preferably contained in a program which, in conjunction with a process control, initiates the automatic execution of the method steps, for example using standardized computers.

The improvement in reliability achieved with the described threading method in connection with a method proposed by the applicant for winding an auxiliary thread even on bare tubes is particularly noticeable. The complete winding, threading and attaching process can be fully robot-controlled. In addition, a batch change can also take place fully automatically, avoiding the manual and time-consuming manipulations that have previously been time-consuming and personnel-intensive.

The manipulable thread store is particularly advantageous when the winding, threading and attachment process is carried out in combination. On the other hand, the thread store can basically only be used for threading or for threading with subsequent attachment, without prior winding. In these cases, too, the advantages mentioned, which result from the precisely controllable thread manipulation, have a positive effect.

Although the invention was mainly described in connection with the manipulation of an auxiliary thread in an operating robot carrying an auxiliary thread supply, the freely manipulable thread store is also advantageous for other thread manipulations, e.g. when threading through direct detection of the spider thread from the cop. In the manner described above, the spinning thread can also be directly and securely threaded directly into thread guiding elements of the spinning machine by manipulating the thread storage device.

Claims (11)

1. A method of threading into a traveller (24) a thread from a bobbin disposed in the spinning position of a ring spinning machine, whereby the thread disposed on the bobbin (40) is held with its free end in a retaining storage means (15) acting in an elastic way and is tensioned against the stationary bobbin (40), a clamped thread portion (6.1) of the thread on the side of the bobbin (40) is supported and advanced in a positionable and controlled manner step-by-step into a defined position at a supporting position directly above the spinning ring (23), which occurs in such a way that the thread portion is held tangentially towards the spinning ring (23) with an inclination ("alpha") towards the plane of the spinning ring (23), whereupon the traveller (24) is pushed onto the thread from the zone of the lower clamping position of the thread portion (6.1) in the direction of the upper clamping position, characterized in that the thread portion (6.1) is positionable in a controlled way by the orifice (16) of the retaining storage means (15) and that the orifice is brought at first into an initial position (A) which is approx. diametrically opposed to an end position (C), which initial position is disposed at the height of the supporting position and is brought thereafter into an intermediate position (B) at a radial distance from the spinning ring (23) via the supporting position in the direction of the end position (C) which already determines the final inclination ("alpha") of the thread portion with regard to the plane of the spinning ring (23) and is lowered thereby and thereafter advanced in the radial direction towards the spinning ring (23) into the end position (C).
2. A method as claimed in claim 1, characterized in that the traveller (24) is pulled up onto the thread (6) from the zone of the lower clamping position of the thread portion (6.1) in the direction of the higher clamping position.
3. A method as claimed in claim 1 or 2, characterized in that the supporting position is formed by a sliding means (28) which is movable in the direction towards the spinning ring and retractable therefrom, with the suction tube (15) with the thread portion (6.1) being guided over said means in such a way that the thread portion (6.1) extends in the intermediate position (B) and in the end position (C) over the end of the sliding means (28) towards the suction tube (15).
4. An apparatus for threading into a traveller (24) a thread from a bobbin disposed in the spinning position of a ring spinning machine, in particular for carrying out the method as claimed in claim 1, with an operating robot cooperating with a process control for optional control of the spinning positions of a spinning machine and with a manipulator fixing device (26) attached to the operating robot, whereby a thread gripper which is coordinated with the fixing device (26) and is in form of a sliding means (28) guided in the fixing device (26), which sliding means is provided at a rod-like tip with a thread guide (25), is displaceable in a controlled manner into the operative zone of the spinning ring (23) and the orifice of a retaining storage means (15) for a free thread portion (6.1) is guidable in a controlled way into a defined position, whereby the fixing device (26) with the thread gripper (28) guided thereon can be coupled with or uncoupled from the ring rail (3) of the spinning machine in a controlled manner and whereby the retaining storage means (15) is provided with means (15) for exercising an elastically acting tensile force on the stored thread portion (6.1) and the clamped thread portion (6.1) of the thread on the side of the bobbin (40) can be advanced and is supportable in a controlled and positionable way step-by-step into a defined position at a supporting position directly above the spinning ring, characterized in that the operating robot is arranged in such-like that the thread portion (6.1) is positionable in a controlled way by the orifice (16) of the retaining storage means (15) and that the orifice can be brought at first into an initial position (A) which is approximately diametrically opposed to the end position (C), which initial position is disposed at the height of the supporting position and thereafter can be brought over the supporting position in the direction of end position (C), which already determines the final inclination ("alpha") of the thread portion to the plane of the spinning ring (23), into an intermediate position (B) which is radially distanced from the spinning ring (23) and is lowerable and thereafter can be brought in the radial direction towards the spinning ring (23) into the end position (C).
5. An apparatus as claimed in claim 4, characterized in that the sliding means is provided at its tip with an arrangement adapted to the surface of the spinning ring, so that an element (31) used for sliding the traveller (24) onto the yarn (6.1) does not touch the yarn wrapped around the thread guide (25).
6. An apparatus as claimed in claim 4, characterized in that the thread guide (25) at the tip of the sliding means (28) is approached to the spinning ring (23) in a form-locked way.
7. An apparatus as claimed in claim 4, characterized in that positioning elements (31; 32) are coupled with the fixing device (26) for the controlled displacement of the traveller (24) on the spinning ring (23).
8. An apparatus as claimed in claim 7, characterized in that a turntable ring (27) which is provided with a controlled activatable turning effect and is concentrically positionable with respect to the bobbin (40) is provided on the fixing device (26) and comprises a tugging apparatus (31) for the traveller (24).
9. An apparatus as claimed in claim 7, characterized in that a controlled activatable nozzle apparatus (32A, 32B) for positioning the traveller (24) in a definable position on the spinning ring (23) is connected on the fixing device (26).
10. An apparatus as claimed in claim 9, characterized in that for positioning the traveller (24) the nozzle apparatus (32A, 32B) is arranged in such a way that an air blast blows the traveller outside of the operative zone of the thread guide (25) and a temporally controlled counterblast holds the traveller on the opposite side of the threading apparatus.
11. An apparatus as claimed in claim 9, characterized in that a nozzle apparatus (32A, 32B) for positioning the traveller (24) is provided in a zone outside of the operative zone of the thread guide (25) and that their operating mode is coordinated with a tugging apparatus (31) which tugs the traveller onto the thread.

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