EP3276057A1 - Filament guide unit of an open-end spinning machine and method for operating a spinning station - Google Patents

Abstract

The present invention relates to a thread guide unit (6) for removing a thread (4) from a rotor (2) of a spinning station (1) of an open-end spinning machine with a discharge pipe (18) and a compressed air nozzle (21). According to the invention, it is proposed that a thread outlet element (19) is provided and an opening (23) of the compressed-air nozzle (21) is formed as a gap between the outlet pipe (18) and the thread outlet element (19). Furthermore, the invention relates to an open-end spinning machine with a plurality of spinning stations (1), each spinning station (1) a spinning unit (3), a thread guide unit (6) according to the preceding description, take-off rollers (5), a winding unit (9, 11) and a Fadenansetzeinheit (15, 14, 16). Furthermore, the invention relates to a method for operating a spinning station (1) of an open-end spinning machine, wherein when the thread (4) must be recognized, a Fadenansetzeinheit (15, 14, 16) a thread end (17) to the thread guide unit (6) moved, where the thread end (17) by a in the spinning unit (3) prevailing vacuum first in the thread guide unit (6) and then in the spinning unit (3) is sucked in, wherein a compressed air flow, in particular from a compressed air nozzle (21) of the thread guide unit ( 6), the suction of the thread end (17) in the spinning unit (3), timed with the attachment of the thread (4), supported.

Description

The present invention relates to a yarn guide unit for removing a yarn from a rotor of a spinning station of an open-end spinning machine with a discharge pipe and a compressed air nozzle.

Furthermore, the invention relates to an open-end spinning machine with a plurality of spinning stations, each spinning station comprises a spinning unit, a thread guide unit, take-off rolls, a winding unit and a Fadenansetzeinheit and a method for operating a spinning station of an open-end spinning machine, wherein a spinning unit produces a thread, the yarn is withdrawn from take-off rolls by a yarn guide unit and wound on a spool by a winding unit and then, when the yarn has to be applied, a yarn take-up unit moves a yarn end to the yarn guide unit where the yarn end first enters the yarn guide unit through a vacuum prevailing in the spinning aggregate then sucked into the spinning unit.

From the German patent DE 25 34 816 is an open-end spinning machine with a thread withdrawal tube and arranged at a distance from the thread withdrawal tube thread guide tube with an ejector known. However, this device has a relatively large footprint.

To fix a thread break beats the DE 25 34 816 before, the torn thread end returned to the spinning rotor. For this purpose, both an induced draft in the rotor housing is switched on and the ejector nozzle is put into operation. Then take-off rollers are turned back to their reverse during the normal spinning spinning direction, wherein the returned yarn piece is blown through the ejector nozzle in a yarn outlet opening of the yarn draw-off tube and there by the prevailing induced draft is withdrawn. Then the thread is separated by means of a thread cutting device. Subsequently, the take-off roller pairs are turned back again while blowing the returned piece of thread back into the thread outlet opening by means of the ejector nozzle. The take-off roller pairs are now rotated back by such an amount that the thread ends are fed back through the thread withdrawal tube exactly into the fiber collection groove of the spinning rotor. There they connect with the deposited fibers, which eliminates the thread breakage. Now the take-off roller pairs are switched back to forward running and set the ejector out of operation. In the course of this process, however, a large amount of compressed air is required for the operation of the ejector nozzle.

The object of the present invention is thus to reduce the disadvantages mentioned and to further improve the device and the method.

The object is achieved by a yarn guide unit, an open-end spinning machine and a method for operating a spinning station of an open-end spinning machine having the features of the independent patent claims.

Proposed is a thread guide unit for removing a thread from a rotor of a spinning station of an open-end spinning machine with a vent pipe and a compressed-air nozzle. During spinning operation, therefore, the yarn coming out of the rotor is drawn off through the withdrawal pipe of the yarn guide unit. At intervals, a thread end must be set again, for example, after a thread break or a cleaner cut. A cleaner cut is the intentional separation of the thread because it does not have the desired properties, such as thickness or purity. To attach the yarn end, it must be brought back into the rotor through the exhaust pipe of the yarn guide unit. This movement of the thread end is supported by a directed compressed air flow emerging from the compressed air nozzle.

According to the invention, a thread outlet element is provided and an opening of the compressed-air nozzle is formed as a gap between the exhaust pipe and the thread outlet element. The thread exit element allows a gentle exit of the thread from the thread guide unit. This is achieved in particular by a rounded shape and / or a low-friction surface of the thread outlet element. Characterized in that the mouth of the compressed air nozzle is formed as a gap between the exhaust pipe and the thread outlet element, a particularly compact design can be achieved.

Advantageously, the mouth of the compressed-air nozzle is annular. Thus, the thread is flowed around evenly, which uses both the most effective compressed air and treated the thread most gently. But the mouth of the compressed-air nozzle can also be semicircular, which directs the thread in the direction of one side of the exhaust pipe and in particular in conjunction with a subsequent kink in the exhaust pipe of advantage. Furthermore, it may also be advantageous if the mouth has a plurality of openings which are arranged along a ring, resulting in increased structural stability.

Furthermore, it is advantageous if air guide elements are provided in the region of the mouth. These spoiler elements serve to generate an air vortex, which flows around the thread and thus generates, amplifies and / or maintains a twist of the thread-usually a Z-twist. The air guide elements can be assigned to the exhaust pipe, the thread outlet element or both. The swirling air can also be generated by arranging the compressed-air nozzle with a component tangential to the mouth. As a result, the compressed air is injected obliquely to the mouth and also generates an air vortex.

It is advantageous if a compressed air connection, in particular a compressed air coupling, is provided for connecting a compressed air hose. Thus, the compressed air hose can be made removable, which is particularly favorable for maintenance work, in which, for example, the compressed air hose or the thread guide unit must be replaced, is low.

It is advantageous if a particular annular air chamber is formed between the exhaust pipe and the thread outlet element. The air chamber distributes the compressed air before it reaches the mouth of the compressed air nozzle. In this case, a uniform distribution of the compressed air, as can be achieved by an annular air chamber, the most vorteil.Vorteilhafterweise the thread exit element is connected to the exhaust pipe by gluing, welding, screwing and / or pressing. The yarn outlet element can therefore be manufactured separately from the exhaust pipe and is then connected to the exhaust pipe by one of the methods mentioned. If the connection is separable, such as when screwing or pressing, then thread exit elements can also be replaced separately, for example, if they are worn or if the thread guide unit is to be optimized for a different type of thread.

It is also advantageous if the exhaust pipe has a change of direction, in particular in the form of a bend, so that the direction of the part of the exhaust pipe on which the yarn outlet element is arranged corresponds to a withdrawal angle of the yarn. In this case, a change of direction of the thread follows the direction change of the exhaust pipe. The direction change of the thread can thus be controlled. A gentle change in direction of the exhaust pipe thus has a gentle change in direction of the thread result, which has a gentle effect on the thread.

It is advantageous if the exhaust pipe has a swirl stop means. Thus, the swirl generated by the rotor is stopped in the thread, so that the thread receives only a predetermined amount of twist and thus predetermined properties having. Furthermore, the exhaust pipe advantageously has at least one thread sensor. With the help of such a thread sensor can first determine whether there is even a thread in the exhaust pipe. Also, yarn breaks can be detected early. In particular, during the piecing process, it can be determined by means of the thread sensor when the thread end passes the thread sensor. So it is known at least at this time the position of the thread end. For a tensioned thread, which is for example held on one side of draw-off rollers and stretched on the other side by the compressed air, then the position of the thread from the known initial position and the rotation of the take-off rolls can be calculated. The knowledge of the position of the thread end is necessary, for example, for a precise attachment of the thread. The more precisely the thread is applied, the greater the likelihood that it will be applied successfully, which in turn increases the productivity of the spinning station.

It is advantageous if a fastening means for fixing the thread guide unit is provided at the spinning position. In particular, with a separable fastener, the yarn guide unit can thus easily replace or remove for a thorough cleaning. Furthermore, it is advantageous if a vacuum connection is provided on the thread guide unit. By means of a vacuum connection, for example, at least some of the compressed air supplied by the compressed air nozzle can be sucked off again, which makes it easier for the vacuum supply assigned to the rotor to maintain a negative pressure. Furthermore, fiber fly, dirt and thread pieces can be sucked off via the vacuum connection, which supports the cleanliness of the thread guide unit.

Advantageously, the exhaust pipe has an inner diameter which is between 2 mm and 4 mm, preferably between 2.5 mm and 3.5 mm and particularly preferably about 3 mm. It is called the inner diameter of the Indicated inner diameter, which has the exhaust pipe predominantly. Inner diameters of the mentioned sizes have proven to be optimal values for the withdrawal of a thread from a spinning aggregate. It is also advantageous if the gap of the mouth has a thickness which is between 0.5% and 15%, preferably between 1.5% and 8% and particularly preferably about 3.5% of the inner diameter of the flue. The thickness is the distance between the thread outlet element and the exhaust pipe at the mouth. Said values make it possible with conventional pressures of the compressed air, a sufficiently strong compressed air flow and / or sufficiently strong air vortices.

The yarn guide unit is designed according to the preceding description, wherein said features may be present individually or in any combination.

Further, an open-end spinning machine is proposed with a plurality of spinning stations, each spinning station has a spinning unit, a yarn guide unit, take-off rolls, a winding unit and a Fadenansetzeinheit. In the spinning operation, the thread comes from the spinning unit and is withdrawn through the thread guide unit through the take-off rolls. From the take-off rolls, the thread then comes to the winding unit, which winds the thread on a spool, in particular a cross-wound bobbin.

According to the invention, the thread guide unit is designed according to one of the preceding claims. The compact design of the thread guide unit also helps the open-end spinning machine to a more compact or more efficient design. Of course, the above-mentioned advantages with respect to gentle thread treatment, better maintainability and increased productivity are also advantageous for the open-end spinning machine.

Finally, a method for operating a spinning station of an open-end spinning machine is proposed. In this case, a spinning unit is a thread ago. The thread is withdrawn from draw-off rollers by a thread guide unit and wound by a winding unit on a spool, in particular a cross-wound bobbin. Then, when the thread has to be attached, so for example after a thread break or after a cleaner cut, a Fadenansetzeinheit moves a thread end to the thread guide unit. There, the thread end is sucked by a pressure prevailing in the spinning unit vacuum first in the thread guide unit and then in the spinning unit.

According to the invention supports a compressed air flow, which escapes in particular from a compressed air nozzle of the yarn guide unit, the prevailing in the spinning unit vacuum and thus the suction of the thread end in the spinning unit, timed with the attachment of the thread. Due to the supporting compressed air flow, the application of the thread takes place faster and more precisely than with the negative pressure prevailing in the spinning unit.

Advantageously, the yarn guide unit is formed as described above. This allows the thread to be treated more gently, the spinning station easier and better maintained and productivity increased.

It is also advantageous if the compressed air flow generates an air vortex. This can be achieved for example by air guide elements in the region of an opening of the compressed air nozzle. Preferably, this air vortex generates and / or reinforces a twist, in particular a Z-twist, in the thread. This avoids that the thread loses its twist and possibly dissolves. If the thread is even subjected to additional rotations by the air vortex, this solidifies the thread in the piecing area and improves the effectiveness of the piecing process. However, the compressed air flow can also be blown through the exhaust pipe through the compressed air nozzle during the withdrawal of the spun yarn and produce an air vortex.

By the air vortex a false twist is caused in the thread, which leads in a known manner to a crimped thread.

It is advantageous if another stream of compressed air, which escapes in particular from the compressed air nozzle of the thread guide unit, supports the suction of the thread end into the thread guide unit. Also, the suction of the thread end in the thread guide unit can thus be faster and more accurate. In addition, the stronger air flow can also detect a not exactly positioned yarn end, which increases the likelihood that the piecing process will be successful, and thus also the productivity of the spinning station.

It is also advantageous if the thread end, after it has been sucked into the thread guide unit and into the spinning unit, is prepared on the edge of a rotor of the spinning unit. The preparation on the edge of the rotor causes on the one hand, that the thread is shortened to a predetermined length. On the other hand, the fibers are partially freed from their rotation at the yarn end, so that the new fibers connect more easily to the yarn end. Overall, the preparation of the thread end at the edge of the rotor has the advantage that both the shortening of the thread as well as ridding of the rotation of the fibers by means of already existing at the spinning station facilities. The rotor does so two or three different tasks. Preferably, a compressed air stream is blown through the compressed air nozzle during the suction and / or dissecting of the thread. By the compressed air flow while a higher tensile force of the thread is achieved and thus the thread also more streamlined. Without additional compressed air flow, the yarn would have to be sucked far into a main vacuum channel in order to obtain the necessary for the preparation of the thread end tensile force, which brings various disadvantages: If several adjacent spinning units are spun simultaneously, there is a risk that thread tufts in the main vacuum channel form. Due to the usually not constant negative pressure in the main vacuum channel over the length of the Open-end spinning machine also result in different yarn tension depending on the position of the spinning station. Furthermore, the entire piece of thread located in the main vacuum channel drops as waste. With the help of the compressed air flow, the required yarn tension is ideally reached when the yarn end is not even in the main vacuum channel. As a result, the disadvantages mentioned are eliminated or at least reduced. Advantageously, the thread end, after it has been prepared at the edge of the rotor, withdrawn. By this step, the positioning of the thread end in the rotor is improved and the rotor can be accelerated without the thread end is rotated.

It is also advantageous if the thread end is prepared by hand outside the thread guide unit. Skilled operators can produce a very well-prepared thread end, in which the rotation of the fibers is offset to the correct extent. In addition, the thread is cut only slightly in the preparation of the thread end by hand and it hardly drops waste. Furthermore, it is advantageous if the thread end is prepared in a Fadenendepräparationsaggregat. Such Fadenendepräparationsaggregat also allows optimal preparation of the thread end with a relatively small amount of waste. The Fadenendepräparationsaggregat can be assigned to a mobile maintenance unit, which is driven to attach the thread to the spinning position. The Fadenendepräparationsaggregat may also be assigned to the spinning station, which is either a separate component or is preferably located in a side arm of the exhaust pipe. If the Fadenendepräparationsaggregat arranged in the side arm of the flue, then the Fadenansetzvorgang can be performed very quickly, because the thread is then already in the exhaust pipe and no longer needs to be introduced into the exhaust pipe.

It is also advantageous if the suction of the thread end into the spinning unit, in particular after the thread end has been withdrawn, is made possible by the rotation of a reversible stepping motor and / or by the dissolution of a loop. By the rotation of a reversible stepping motor, the thread end can be conveyed a predetermined distance in the spinning unit. Likewise, the thread end is conveyed by the dissolution of a loop a predetermined distance in the spinning unit, provided that the loop had a predetermined length. The yarn end is so controlled moves during piecing, resulting in reproducible results. This is advantageous both for the quality of the connection of the thread end with the newly spun yarn and for the reliability of the piecing process.

In summary, a piecing process can thus take place as follows: The thread end is moved by a thread feed unit to the thread guide unit. A spin box assigned to the spinning station or the spinning unit is closed and the thread end is sucked into the thread guide unit. The spinning box is now opened and the thread is unwound, so that the thread end is conveyed into a suction device of the spinning box or the spinning unit. Then the spin box is almost, but not completely, closed, whereby the thread is pressed to the edge of the rotor. The rotor is now accelerated and the thread is pulled back and forth several times, whereby the thread at the rotor edge is separated and prepared. Thereafter, the thread is withdrawn from the rotor, but only so far that it is still in the thread guide unit. After closing the spinning unit, the thread is fed back into the rotor for piecing.

Furthermore, it is advantageous if the position of the thread end is detected by means of at least one sensor in a discharge pipe associated with the yarn guide unit. By the known position of the thread end of the piecing process can be controlled even more precisely, for example by the length of the thread return, or by the choice of the times of startup of the rotor or the beginning of the withdrawal of the thread. Preferably the compressed air flow is controlled taking into account the position of the thread end. By the compressed air flow, the attachment of the thread end can also be influenced. In this case, both the timing and the duration and possibly even the strength of the compressed air flow can be influenced.

Finally, it is advantageous if, for cleaning the yarn guide unit and / or the spinning unit at intervals a compressed air stream is blown through the compressed air nozzle. Cleaning by compressed air is efficient and feasible with existing means. More complex, for example, mechanical, cleaning can thus be carried out with longer time intervals from each other. On the other hand, cleaning with the compressed air stream blown through the compressed air nozzle can be carried out before each piecing operation and even while the spinning operation is in progress.

The method for operating a spinning station is carried out according to the preceding description, wherein said features may be present individually or in any combination.

Figuren 1a, 1b und 1c

schematische Seitenansichten einer Spinnstelle einer Offenend-Spinnmaschine,

Figur 2

einen Längsschnitt einer Fadenführungseinheit,

Figur 3

einen Längsschnittschnitt einer weiteren Fadenführungseinheit,

Figur 4

einen Längsschnitt einer weiteren Fadenführungseinheit,

Figur 5

eine Seitenansicht eines Fadenaustrittselements,

Figuren 6a, 6b und 6c

Querschnitte durch verschiedene Fadenführungseinheiten und

Figur 7

einen Querschnitt durch eine weitere Fadenführungseinheit und

Figur 8

einen Querschnitt durch eine weitere Fadenführungseinheit.

Further advantages of the invention are described in the following exemplary embodiments. Show it:

Figures 1a, 1b and 1c

schematic side views of a spinning station of an open-end spinning machine,

FIG. 2

a longitudinal section of a yarn guide unit,

FIG. 3

a longitudinal section section of another yarn guide unit,

FIG. 4

a longitudinal section of another yarn guide unit,

FIG. 5

a side view of a thread exit element,

Figures 6a, 6b and 6c

Cross sections through different thread guide units and

FIG. 7

a cross section through a further yarn guide unit and

FIG. 8

a cross section through another thread guide unit.

FIG. 1a shows a schematic side view of a spinning station 1 of an open-end spinning machine in spinning operation. Fiber material is introduced into a rotor 2 of a spinning unit 3 of the spinning station and spun into a thread 4. The thread 4 is withdrawn from a pair of take-off rollers 5 via a yarn guide unit 6 from the rotor 2. The thread guide unit 6 in this case has a groove 7, in which a retaining spring 8 of the spinning unit 3 engages and thus connects the thread guide unit 6 with the spinning unit 3. After the take-off roller pair 5, the yarn 4 is wound by a traversing unit 9 on a cross-wound bobbin 10. The cross-wound bobbin 10 is held by a bobbin holder 11 and driven by a drive roller 12.

At intervals, a compressed air stream is blown through a compressed air nozzle 13 of the yarn guide unit 6 for cleaning the yarn guide unit 6 and the spinning unit 3. Dirt and fiber fly are thereby solved and sucked off by a vacuum device, not shown here, of the spinning unit 3. In spinning operation, a suction nozzle 15 displaceable by a motor 14 and a yarn catcher 16 are not required. After a thread break or a cleaner cut the thread 4 runs on the cross-wound bobbin 10. In order to obtain a continuous thread 4 on the cross-wound bobbin 10, the thread end 17 must first be found and then attached to the spinning unit 3. To search the yarn end 17, the suction nozzle 15 is displaced by the motor 14 so that the opening of the suction nozzle 15 is just above the surface of the cheese 10. The cross-wound bobbin 10 is then slowly rotated by the drive roller 12 counter to the direction of rotation during spinning operation until the yarn end 17 is sucked into the suction nozzle 15. Then the suction nozzle 15 is removed by the motor 14 again from the cheese 10, so that the thread 4 spans between the cheese 10 and the suction nozzle 15. The thread catcher 16 can then grip the opened thread 4. This time is in FIG. 1 b shown.

The thread 4 is then inserted from the thread catcher 16 in the traversing unit 9 and the take-off roller pair 5 and moved to the opening of the thread guide unit 6. There, the thread 4 is sucked into the thread guide unit 6 by the vacuum prevailing in the spinning unit 3. This process is supported by a compressed air flow blown by the compressed air nozzle 13. The thread end 17 is now in the thread guide unit 6, as in Figure 1c shown.

In the further course of the piecing process then the withdrawal roller pair 5 is rotated backwards, so that the thread end 17 of the spinning unit 3 prevailing negative pressure, supported by the compressed air flow from the compressed air nozzle 13, is moved further into the yarn guide unit 6 to the rotor 2. At the rotating rotor edge, the thread end 17 is then separated and prepared. Then the thread end 17 is withdrawn from the pair of withdrawal rollers 5 again something. Then the actual application takes place, in which the rotor 2 is raised to its Ansetzgeschwindigkeit and the take-off roller pair 5 is rotated backwards. The thread end 17 is transported by the pressure prevailing in the spinning unit 3 negative pressure, combined with a timed compressed air flow from the compressed air nozzle 13, in the rotor 2, where it connects with fibers located there. Then the normal spinning operation is resumed.

FIG. 2 shows a longitudinal section of a simple yarn guide unit 6. The yarn guide unit 6 has a discharge pipe 18 with an inner diameter D and a yarn outlet element 19. A compressed air connection 20 leads to a compressed air nozzle 21, which is provided as a recess in the exhaust pipe 18. The compressed air nozzle 21 also comprises an annular air chamber 22, which is formed between the exhaust pipe 18 and the thread outlet element 19. Through this annular air chamber 22, the compressed air is evenly distributed. Finally, an orifice 23 of the compressed air nozzle 21 is formed as a gap between the exhaust pipe 18 and the yarn outlet element 19. This allows a particularly compact design. The thickness T of this gap influences the strength of the achievable compressed air flow. The mouth 23 is also annular, so that the compressed air flow emerge evenly distributed and can flow around the thread from all sides. Thus, the compressed air flow is utilized most efficiently and treated the thread most gently.

In the spinning operation, a thread is withdrawn from the rotor of a pair of delivery rollers through the exhaust pipe 18. The thread leaves the thread guide unit 6 at the thread exit element 19. The compressed air nozzle 21 is, as described above, needed to blow the thread in the direction of the rotor. In addition, a compressed air flow blown through the compressed air nozzle 21 may be used to clean the exhaust pipe and / or the spinning unit.

In the following description of in FIG. 3 illustrated alternative thread guide unit 6 are for features that compared to in FIG. 2 illustrated first embodiment in its configuration and / or Mode of action identical and / or at least comparable, the same reference numerals used. Unless these are explained in detail again, their design and / or mode of action corresponds to the design and mode of action of the features already described above. For the sake of clarity, the inner diameter D and the thickness T are no longer marked in this and in the following figures.

For faster connection and disconnection of a compressed air hose, the yarn guide unit 6 has a compressed air coupling 24. This brings a time advantage over a conventional compressed air connection, especially during maintenance and / or cleaning.

Furthermore, the thread guide unit 6 has a vacuum connection 25, which is likewise designed as an air coupling. For example, negative pressure is switched on via the vacuum connection 25 when a thread end is first sucked into the thread guide unit 6. Then this negative pressure supports the pressure prevailing in the spinning unit vacuum and sucks at least a portion of the injected from the compressed air nozzle 21 compressed air again. The negative pressure is also turned on when the exhaust pipe 18 is cleaned by means of compressed air. Then dirt and fiber fly are sucked through the vacuum line.

The yarn guide unit 6 further comprises a groove 7. In cooperation with retaining springs of the spinning unit this groove 7 serves to secure the yarn guide unit 6 on the spinning unit.

The exhaust pipe 18 has a kink 26, so that the yarn is at least substantially in the direction of the part of the exhaust pipe 18, on which the yarn outlet element 19 is arranged, is withdrawn. Thus, the change in direction of the thread at the thread outlet element 19 is very low, which has a correspondingly low friction of the thread at the thread outlet element 19 result.

Furthermore, the exhaust pipe 18 on spin stop means 27. As a result, the swirl generated by the rotation of the rotor is stopped in the thread, which has a defined twist in the thread and thus constant thread properties result.

Finally, a thread sensor 28 is provided in the exhaust pipe 18. The thread sensor 28 consists of a light barrier unit 28.1 and a mirror 28.2. A light source of the light barrier unit 28.1 emits light onto the mirror 28.2. The light reflected by the mirror 28.2 is then in turn detected by a light sensor of the light barrier unit 28.1. Located in the area of the yarn sensor 28, a thread in the exhaust pipe 18, the light is blocked or at least attenuated by the thread and the light sensor registers that a thread is in the exhaust pipe 18. Since the position of the yarn sensor 28 in the exhaust pipe 18 is known, even the position of the yarn end can be registered when the time is fixed at which the thread blocks or releases the light. With the help of the detected position of the thread end then, for example, the piecing process can be performed even more precise.

At the in FIG. 4 shown embodiment of a yarn guide unit 6, the exhaust pipe 18 a side arm 29. This side arm 29 leads to a Fadenendepräparationsaggregat 30, which is shown here only schematically. If, for example, the thread is to be rewound after a thread break, then, as described above, the thread end is sucked into the thread guide unit 6. Now, if a negative pressure is applied to the side arm 29, the thread end passes over the side arm 29 to the yarn end preparation unit 30, where the thread end is shortened and the rotation of the fibers is partially canceled. The thread end is now slightly withdrawn, so that it is no longer in the side arm 29. For further application of the yarn end, a negative pressure is now applied in the main arm 31 of the exhaust pipe 18 and continued as described above. FIG. 5 shows a side view of an alternative embodiment of a thread exit element 19. This thread exit element 19 is provided with air guide elements 32. If now compressed air between the thread outlet element 19 and the exhaust pipe 18 is blown, an air vortex is generated in the compressed air flow through the air guide elements 32. With the help of this air vortex, a twist, usually a Z-twist, is produced in the thread or the twist in the thread is retained and does not dissolve. But the air guide elements 32 may also be associated with the exhaust pipe 18, or partially the thread outlet member 19 and partially the exhaust pipe 18th

The Figures 6a, 6b and 6c show cross sections of various embodiments of yarn guide units 6, wherein the cross sections in the region of the mouth 23.

In FIG. 6a the mouth 23 is annular. This ensures a uniform flow around the thread with compressed air and is particularly thread-friendly.

FIG. 6b shows a semicircular orifice 23. Such an orifice 23 is used in particular when, for example, by a kink 26 in the exhaust pipe 18, a certain direction of the thread is specified and the compressed air flow to direct the thread in this direction.

Further shows FIG. 6c an orifice 23 in which a plurality of openings 33 are arranged along a ring, of which only two are provided with a reference numeral for the sake of clarity. Such a design of the mouth 23 provides increased stability of the yarn guide unit 6 in the region of the mouth 23.

Further shows FIG. 7 a cross section through another thread guide unit 6. In this yarn guide unit 6 opens the compressed air nozzle 21 directly in the mouth 23. Further, the compressed air nozzle 21 is offset from the axis of the exhaust pipe 18 and the thread outlet member 19 and thus arranged with a tangent to the mouth 23 component. By this staggered arrangement of the compressed-air nozzle 21, the injected air receives a tangential component, so that here also an air vortex is generated, with the advantages described above. It is also a combination of tangent to the mouth arranged compressed air nozzle with air guide elements conceivable, so that an air vortex of the correct strength is generated.

Finally shows FIG. 8 a cross-section through a further yarn guide unit 6. This yarn guide unit 6 has in addition to the mouth 23 an annular air chamber 22. The compressed air nozzle 21 is similar to the embodiment of FIG. 7 , offset from the axis of the exhaust pipe 18, the yarn outlet member 19 and the annular air chamber 22 and thus has a tangent to the mouth 23 component. Again, the injected air receives a tangential component by the staggered arrangement of the compressed air nozzle 21. This also creates an air vortex, with the advantages described above.

Furthermore, a combination of the embodiments of the FIGS. 7 and 8th conceivable. The compressed air is blown in such a way that part of the compressed air first flows into the annular air chamber 22 and from there it reaches the mouth 23. The other part of the compressed air is injected directly into the mouth 23. In the mouth so both parts of the compressed air flow come together again. So a particularly effective air vortex can be generated.

The present invention is not limited to the illustrated and described embodiments. Variations within the scope of the claims are also possible as a combination of features, even if they are shown and described in different embodiments.

LIST OF REFERENCE NUMBERS

1

spinning unit

2

rotor

3

spinning unit

4

thread

5

Off rollers

6

Thread guiding unit

7

groove

8th

retaining spring

9

Traversing unit

10

cheese

11

spool holder

12

drive roller

13

compressed air nozzle

14

engine

15

suction nozzle

16

thread catcher

17

thread end

18

exhaust pipe

19

Thread exit element

20

Compressed air connection

21

compressed air nozzle

22

Annular air chamber

23

muzzle

24

Compressed air coupling

25

Vacuum port

26

kink

27

Twist stop means

28

thread sensor

29

sidearm

30

Yarn end preparation unit

31

main arm

32

air guide

33

opening

D

Inner diameter

T

thickness

Claims (19)

Thread guide unit for pulling a thread (4) from a rotor (2) of a spinning station (1) of an open-end spinning machine with a discharge pipe (18) and a compressed-air nozzle (21),
characterized, in that
a thread outlet element (19) is provided and an orifice (23) of the compressed-air nozzle (21) is formed as a gap between the exhaust pipe (18) and the thread outlet element (19). Yarn guiding unit according to the preceding claim, characterized in that the mouth (23) of the compressed-air nozzle (21) is annular and / or semicircular and / or has a plurality of openings (33) arranged along a ring Thread guide unit according to one of the preceding claims, characterized in that in the region of the mouth (23) air guide elements (32) are provided for generating an air vortex, wherein the air guide elements (32) associated with the exhaust pipe (18) and / or the thread outlet element (19) and / or the compressed-air nozzle (21) is arranged with a component tangential to the mouth (23). Yarn guiding unit according to one of the preceding claims, characterized in that a compressed air connection (20; 24), in particular a compressed air coupling (24), is provided for connecting a compressed air hose. Thread guide unit according to one of the preceding claims, characterized in that between the exhaust pipe (18) and the thread outlet element (19) is formed a particular annular air chamber (22) and / or the thread outlet element (19) with the Discharge pipe (18) is connected by gluing, welding, screwing and / or pressing. Yarn guiding unit according to one of the preceding claims, characterized in that the draw-off pipe (18) has a change of direction, in particular in the form of a bend (26), so that the direction of the part of the draw-off pipe (18) on which the thread exit element (19) is a withdrawal angle of the thread (4). Thread guide unit according to one of the preceding claims, characterized in that the exhaust pipe (18) has a twist stop means (27) and / or at least one thread sensor (28). Yarn guiding unit according to one of the preceding claims, characterized in that a fastening means (7) for fastening the yarn guide unit (6) to the spinning station (1) is provided and / or a vacuum connection (25) is provided on the yarn guide unit (6). Thread guide unit according to one of the preceding claims, characterized in that the exhaust pipe (18) has an inner diameter (D) which is between 2 mm and 4 mm, preferably between 2.5 mm and 3.5 mm and particularly preferably about 3 mm and or the gap of the mouth (23) has a thickness (T) which is between 0.5% and 15%, preferably between 1.5% and 8% and more preferably about 3.5% of the inside diameter (D) of the flue (18). Open-end spinning machine with a plurality of spinning stations (1), each spinning station (1) a spinning unit (3), a thread guide unit (6), take-off rolls (5), a winding unit (9, 11) and a Fadenansetzeinheit (15, 14, 16),
characterized in that the yarn guide unit (6) is designed according to one of the preceding claims. Method for operating a spinning station (1) of an open-end spinning machine, wherein a spinning unit (3) produces a thread (4), the thread (4) is withdrawn from take-off rolls (5) by a thread guiding unit (6) and fed by a winding unit (9 , 11) is wound onto a spool (10) and, when the thread (4) has to be applied, a thread applying unit (15, 14, 16) moves a thread end (17) to the thread guiding unit (6) where the thread end (17 ) is sucked into the yarn guide unit (6) and then into the spinning unit (3) by a negative pressure prevailing in the spinning unit (3),
characterized, in that
a stream of compressed air, in particular from a compressed air nozzle (21) of the thread guide unit (6), the suction of the thread end (17) in the spinning unit (3), timed with the attachment of the thread (4) supported. Method according to the preceding claim, characterized in that the yarn guide unit (6) is designed according to one of claims 1 to. 7 Method according to one of the preceding claims, characterized in that the compressed air current generates a vortex of air, which preferably produces a swirl, in particular a Z-twist in the yarn (4) and / or amplified and / or during the withdrawal of the spun yarn (4) caused by the exhaust pipe (18) a false twist in the thread (4). Method according to one of the preceding claims, characterized in that a further compressed air stream, which escapes in particular from the compressed air nozzle (21) of the thread guide unit (6), supports the suction of the thread end (17) in the thread guide unit (6). Method according to one of the preceding claims, characterized in that the thread end (17), after it has been sucked into the yarn guide unit (6) and in the spinning unit (3), at the edge of a rotor (2) of the spinning unit (3) is prepared and preferably a compressed air stream is blown through the compressed air nozzle (21) and / or the thread end (17) after it has been prepared at the edge of the rotor (2) is retracted during the suction and / or preparation of the thread. Method according to one of the preceding claims, characterized in that the thread end (17) outside the thread guide unit (6) is prepared by hand and / or in a Fadenendeprpparationsaggregat (30) is prepared, wherein the Fadenendepräparationsaggregat (30) a mobile maintenance unit of the open Spinning machine is assigned and / or the spinning station (1) is associated and is preferably in a side arm (29) of the exhaust pipe (18). Method according to one of the preceding claims, characterized in that the suction of the thread end (17) in the spinning unit (3), in particular after the thread end (17) has been withdrawn, made possible by the rotation of a reversible stepping motor and / or by the dissolution of a loop becomes. Method according to one of the preceding claims, characterized in that by means of at least one sensor (28) in one of the thread guide unit (6) associated with the exhaust pipe (18), the position of Thread end (17) is detected and preferably the compressed air flow is controlled taking into account the position of the thread end (17). Method according to one of the preceding claims, characterized in that for cleaning the yarn guide unit (6) and / or the spinning unit (3) at intervals a compressed air flow through the compressed air nozzle (21) is blown.

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