DRAWING FRAME DEVICE, SPINNING STATION AND PROCEDURE

Abstract

The invention relates to a drafting device for a textile machine, in particular an air-jet spinning machine, wherein the drafting device can have several pairs of rollers that can be driven independently of one another. The roller pairs can be designed and arranged to guide a fiber ribbon between an upper roller and a lower roller of each pair during their rotational operation in order to stretch the fiber ribbon. The drafting device can be designed and configured to carry out a spin-up process after the fiber ribbon has been cut within the drafting device. To optimize the spinning process, the drafting device is designed and configured to selectively add at least two pairs of rollers via their drives during the spin-up process.

Description

[0001] The invention relates to a drafting device. The invention relates to a spinning station. The invention relates to a method. The invention relates to a control device. The invention relates to a textile machine. The invention relates to a computer program product.

[0002] Drafting devices are known in the art. They are used particularly in textile machines, and more particularly in air-jet spinning machines for air-jet spinning. In air-jet spinning, a fiber sliver, also called a draw frame sliver, is drawn according to the desired yarn count by means of a drafting device, in particular a 4-roller drafting device, and fed to a spinneret. The spinneret is in particular a functional device of a spinning station. Within the spinneret, a portion of the supplied fibers can be wound around the parallel fiber core by means of a rotational flow. This creates the air-jet-specific yarn structure of a yarn core consisting of parallel fibers and wrapped fibers lying at a specific angle to the yarn core, which can ensure the strength of the yarn.

[0003] If individual rollers in the drafting system are idle for extended periods, the fiber sliver may become dented over time. Likewise, if the textile machine and / or the drafting system are shut down frequently, the fiber sliver can be a potential source of defects in the air-jet spinning process. In the event of a thread break, thread cut, or fiber sliver break, piecing may be required to resume spinning. In this case, the denting of the fiber sliver can complicate piecing and lead to a weak point in the resulting thread.

[0004] Spinning stations are known in the art that can be used for piecing in addition to spinning a thread. Here, a thread end, for example after a thread break, is prepared for piecing so that fibers can be reattached to the thread and the thread can be spun further. This makes it possible to continue a spinning process, for example after a thread break has occurred. In air-jet spinning machines according to one embodiment, piecing is based in particular on bringing together a loosened thread end in the vortex chamber of the air-jet spinneret with newly arriving fibers of the fiber sliver. In particular, the timing of a thread end return and the speeds of the drafting device, as well as their times, are important for piecing a thread. Piecing, particularly if the timing is incorrect, can lead to irregularities in the thread, which can negatively impact the yarn quality.

[0005] The object of the invention is therefore to improve a spinning process, in particular piecing, to make the resulting thread more uniform and thus to reduce resources for a spinning process.

[0006] The problem is solved by a drafting device having the features of claim 1. The problem is solved by a spinning station having the features of claim 9. Furthermore, the problem is solved by a method having the features of claim 12. The problem is solved by a control device having the features of claim 13. The problem is further solved by a textile machine having the features of claim 14. The problem is solved by a computer program product having the features of claim 15.

[0007] Advantageous embodiments of the invention are the subject of the subclaims.

[0008] According to one aspect, the object is achieved by a drafting device having the features of claim 1.

[0009] In this case, a drafting device can be designed for a textile machine. The textile machine can in particular be an air-jet spinning machine. In this case, the drafting device can have a plurality of roller pairs that can be driven differently from one another. In this case, the roller pairs can be designed and arranged to guide a fiber sliver between a top roller and a bottom roller of the respective roller pairs during their operation in order to draw the fiber sliver. In this case, the drafting device can be designed and arranged to carry out a piecing process after the fiber sliver has been separated in the drafting device. In this case, the drafting device can be designed and arranged to connect at least two roller pairs in a defined manner via their drive during the piecing process. In this way, the roller pairs can in particular be controlled in a defined manner and operated accordingly in different operating modes.Different operating modes can be differentiated by at least one parameter, as described elsewhere. In particular, the rollers can have different speeds and / or different accelerations. This makes it possible, for example, to accelerate from a complete stop, i.e., from a standstill, to an operating state (linear) during a piecing process. This also eliminates the need for the rollers to warm up from a standstill mode. Instead, the rollers can be kept warm. This can improve spinning, especially piecing, and the yarn can be made more uniform, thus reducing the resources required for a spinning process.

[0010] A drafting system device can also comprise a drafting system and / or be referred to as such. Such a drafting system can in particular comprise a number of roller pairs. These can in particular each comprise at least one active roller, which can be referred to as the active roller or as the drive roller. The drive roller can preferably be an individually driven roller which is coupled to an individual drive for driving the roller. If only one roller of a roller pair is active, the other roller can follow the first, active roller and can be driven by it. The inactive roller is in particular a passive roller. A contact pressure can be formed between the two rollers in order to enable the transmission of force between the drive roller, as the active roller, and the following roller, as the passive roller.

[0011] A fiber sliver (also referred to as a fiber strand) is a band of longitudinally parallel individual fibers that are held together by static friction. However, the fibers are not yet combined to form a thread, as described in particular elsewhere. Within a spinneret, a portion of the supplied fibers from the fiber sliver can be wound around a fiber core made up of parallel fibers, which forms the yarn core, by means of a rotational flow. This creates the air-jet yarn structure specific to a yarn core made up of parallel fibers and, at a specific angle, surrounding wrapped fibers that wind around the yarn core and can ensure the strength of the yarn. The spinneret can be a part (an active functional device) of a spinning station, as described elsewhere. Furthermore, the spinneret can be part of a spinning chamber orthe spinneret can be called a spinning chamber.

[0012] A piecing process can be a method and / or a process step in which a fiber sliver end is tied to a yarn end in order to continue the spinning process. Piecing is based, in particular, on bringing together a loosened yarn end in the spinning chamber / spinneret with newly arriving fibers from the supplied fiber sliver end. The timing of the return movements, in particular of the loosened yarn end, and the speeds and / or running times of the drafting device, in particular for feeding fibers in a quantity advantageous for spinning, in particular piecing, can be determined as described below.

[0013] In a spinning machine, particularly an air-jet spinning machine, piecing is based in particular on bringing a prepared thread end together with newly arriving fibers of the fiber sliver, particularly in a vortex chamber of the spinneret, which forms an air-jet spinneret. A prepared thread end is understood to be a thread end that has been cut and then unraveled in order to bring the fiber ends of the thread end from a partially twisted into an almost completely, more preferably completely, longitudinally parallelized arrangement. An almost completely longitudinally parallelized arrangement is an arrangement of the fiber ends in which, during the unraveling process for the longitudinal parallelization of the fiber ends, not all fiber ends were longitudinally parallelized, but rather a small proportion of the fiber ends, due to tolerances, did not undergo any longitudinal parallelization due to the process.

[0014] Of particular importance for the piecing process are the timing of the yarn end return and the speeds and / or running times of the drafting device, among other things for feeding the fiber sliver end. According to one embodiment, a piecing process can comprise at least one of the following steps: In one step, in particular, an upper thread (thread on the surface of the thread-guiding package) can be caught from a package in a known manner by a rotationally and / or translationally movable thread end catching device, in particular a pivotable suction nozzle that can be subjected to negative pressure, and transferred to a thread end preparation device. During this time, a thread take-off device can be opened to introduce the thread into the thread take-off device. The thread take-off device comprises, in particular, a pair of rollers with an upper and a lower roller, of which at least one roller is an active roller and the other roller is a passive roller, as described above.The active roller can be driven by a single drive. In one step, in particular via deflection contours, the thread can be inserted into the thread take-up (also referred to as take-up) from the thread end catching device during its movement for transferring the carried thread end to the thread end preparation. The take-up can in particular be designed to take over the thread. The take-up can in particular be carried out by the thread being inserted into the take-up with a thread section from the thread end catching device during its movement and then clamped by the latter, in particular after the thread end has been transferred from the thread end catching device to the thread end preparation. In particular, after being passed through the thread end catching device, the thread rests with a thread section on a pair of scissors and / or is arranged with a thread section or the thread end in front of a receiving opening of a dissolving tube of the thread preparation.In particular, the thread take-off subsequently clamps the thread. In a subsequent step, the scissors, in particular, cut the thread to produce a cut thread end in preparation for a subsequent step of unraveling the thread end. According to an alternatively preferred embodiment, the unraveling of the thread end can be performed without a prior step of cutting the thread.

[0015] Catching the yarn end and guiding it in a direction opposite to the yarn travel during the spinning process is referred to as rewinding or thread rewinding. This rewinding can occur in one step or several sub-steps, in which case we speak of a first, second, ..., xth rewind.

[0016] In one step, the (cut) thread end can be sucked in and opened by introducing a stream of compressed air into the opening tube. In one step, a first return of the thread can take place by reversely rotating the take-up clamping the thread. The first return of the thread end to an outlet of a thread take-off channel of the air spinneret can be supported by introducing an air stream accompanying the thread end or the thread into a thread guide channel guiding the opened thread end, wherein the thread guide channel can be part of the thread end preparation and in particular can comprise or form the opening tube and more preferably extend to the outlet of the thread take-off channel of the air spinneret. Thus, in a first return step, the thread end can be guided through the thread guide channel to the outlet of the thread take-off channel of the air spinneret.

[0017] In one step, particularly after the first return, a thread loop can be placed in a pneumatic thread storage device, which is arranged in the thread travel direction between the air spinneret and the package or the package holder for rotatably holding the package, particularly between the take-up and the package or the package holder. The thread loop can serve as compensation, since the run-up times and accelerations of at least one of a drive shaft for contact-driven driving of the package, a package, a drafting device, and / or a take-up can vary.In particular, during the steps described above, an output roller of the drafting device, in particular the output bottom roller, rotates in order to comb out the fiber sliver clamped between the output bottom and top rollers and to keep the drive of the output roller, in particular the output bottom roller, and / or the rubber covering of the output rollers warm.

[0018] In one step, in particular, a second return of the thread follows. This takes place in particular into a vortex chamber (also referred to as a spinning chamber) so that the unraveled thread end can be captured by the air flow. For this purpose, the air flow can be introduced into the vortex chamber of the air spinneret via the spinnerets ending in the vortex chamber, which generates a suction flow in the thread take-off channel of the air spinneret, whereby the thread end can be sucked into the thread take-off channel and transported along it to the vortex chamber of the air spinneret in such a way that the thread end is positioned in the vortex chamber between a sliver guide element and a spinning cone (also referred to as a yarn formation element) of the spinneret in order to be captured by the vortex air flow.The air spinneret is typically constructed with a two-part housing, with one housing part housing the fiber sliver inlet and the other housing part housing the yarn-forming element with the yarn take-off channel. The two housing parts are designed to be movable relative to each other and, when coupled, form the vortex chamber formed between the fiber sliver inlet and the yarn-forming element.

[0019] In one step, the rotating output roller, especially the output bottom roller, is stopped. The drafting device can be started depending on input parameters, which is referred to as run-up.

[0020] The input parameters for the run-up, which in particular define a run-up profile, can in particular be one of an advance time, a piecing speed, a speed profile, a speed for a first stage, a duration of operation of a first stage, and / or a total run-up time of the drafting device or of the at least three roller pairs arranged therein, consisting of an input roller pair, a middle roller pair, and an output roller pair. Furthermore, a pair of apron rollers can be provided, which is arranged between the middle roller pair and the output roller pair. The pair of apron rollers can preferably follow the run-up profile of the output roller pair, particularly during run-up.

[0021] A speed profile constituting the run-up profile can, in particular, comprise at least one of four subparameters. This can be selected from a speed for a first stage, a duration of operation of a first stage, a total run-up time of the drafting system device, and a yarn take-off acceleration, which, in particular, determines the total run-up time of the yarn take-off (take-up).

[0022] In particular, during a dwell time of the yarn take-off, the yarn end can be held in the spinning chamber, which makes it possible to adjust the preparation of the drafting device in a defined manner.

[0023] In one step, the yarn take-off, in particular, accelerates at the end of its dwell time according to a predetermined and / or input acceleration. "Running" refers to the driven operation of the yarn take-off. During this time, the drafting system can also accelerate. After being connected to the fiber sliver, the yarn is drawn from the spinning chamber by means of the yarn take-off for continuous spinning. The piecing process is completed, in particular, after the acceleration times have elapsed.

[0024] According to a preferred aspect, it can be provided that at least two pairs of rollers are selected for a defined addition from the list of the following pairs of rollers: an input pair of rollers, a middle pair of rollers and / or an apron pair of rollers.

[0025] The remaining roller pairs of the drafting device (input roller pair, middle roller pair(s) and / or apron roller pair) can preferably be switched on in a defined manner in order to start a defined drawing-in and drawing of the fiber sliver. In this context, one of the aforementioned roller pair types can be referenced as the remaining roller pairs. The switching on can take place, in particular, after a first return step. Furthermore, in particular, the switching on can take place after a thread loop has been laid. Alternatively or additionally, the switching on can take place during or after a step of combing out the fiber sliver. Alternatively or additionally, the switching on can take place during or after a step of keeping a drive of the output roller pair warm, in particular a drive of the output bottom roller, and / or the rubber covering of at least one of the output rollers.

[0026] Alternatively or additionally, at least one of the aforementioned roller pairs, in particular an output roller pair, further in particular an output bottom roller, can be switched on in a defined manner when a yarn take-off runs up. In particular, a defined switching on of at least one of the roller pairs can take place, as also described elsewhere, in such a way that a fiber sliver is fed to a spinning station in a coordinated manner while a yarn end is being unraveled and / or while it is part of a first and / or a second return and / or an x-th return. In this case, at least the run-up profile of a roller pair can have a so-called piecing ramp with at least two support points, as described elsewhere. In this regard, reference is made to the referenced embodiments, and repetition is omitted for reasons of readability and compactness.

[0027] A drafting device can, in particular, comprise an apron that rotates around an apron roller of a pair of apron rollers, in particular a bottom apron roller. One of the apron rollers, the bottom apron roller or the top apron roller, can be driven by an apron roller drive. The apron roller pair is arranged, in particular, between the center roller pair and the output roller pair of the drafting device. Different adjustable peripheral speeds of roller pairs arranged directly one after the other in the fiber sliver transport direction enable a defined drawing of the fiber sliver between these two roller pairs.

[0028] According to a preferred embodiment, it can be provided that, while the output bottom roller pair rotates to comb out the fiber sliver and / or keep it warm, in particular during the steps described elsewhere from catching a top thread end to a first return, not only is the output roller drive left in operation to drive the output rollers, but that the apron roller drive can also be switched on to drive the apron rollers, with the belt bottom roller in particular being actively driven, while the drives of the other roller pairs, such as the input roller pair drive and / or the center roller pair drive, are in particular stationary. This allows the fiber sliver to be severed between the center roller pair and the apron roller pair, whereby the severed fiber sliver piece can be removed from the drafting device by the rotating apron and output rollers.

[0029] In particular, after combing out a fiber sliver, the output roller drive and / or the apron roller drive stop, and the spinning station returns to its operating position, which corresponds to the normal spinning position (a spinning pressure is activated, the air spinneret is closed). The next process steps can then take place, as described elsewhere. The final return of the yarn can follow, and the active rollers of the drafting device can be accelerated using the described parameters. For this purpose, the parameters can be adjusted in such a way that they are used to transport the fiber sliver, in particular into the vortex chamber in front of the yarn formation element of the air spinneret.

[0030] In other words, this means that significantly longer running times can be entered than if the sliver were already present between the apron roller pair and the output roller pair. This makes it possible for the initial start-up of the belt roller motor, in particular the apron roller drive, and the output roller drive to take place without sliver in this area. This prevents the breakaway torque from having an effect in this zone. As a result, the breakaway torque cannot influence the sliver, and thus cannot affect the thread or yarn quality. Alternatively or additionally, piecing can occur while the drafting system is already running.

[0031] The preferred aspects and embodiments described here and elsewhere make it possible to reduce or completely prevent minimally different starting times of the individual drafting system roller drives, as well as slight deviations from target / actual parameters, such as target / actual speed(s), in particular of the output roller drive, and more particularly of the output bottom roller drive. Furthermore, the factors cited elsewhere as disadvantageous can be improved, for example, by avoiding increased pressure forces of the drafting system rollers. This makes it possible to reduce or completely prevent incorrect drafts during piecing. This also makes it possible to reduce or prevent the stuttering acceleration of the apron roller pair, which was previously noticeable, particularly in high-speed camera recordings.

[0032] Here and elsewhere, in particular, it is meant with respect to a reduction or with respect to a reduction of an event or risk selected from a probability of occurrence, a frequency of occurrence.

[0033] The preferred aspects and embodiments described here and elsewhere enable the circumvention of different breakaway torques, in particular of the apron roller pair, and / or the circumvention of an (initial) target / actual speed deviation, in particular of the output roller drive, for different drafting system settings by means of software-based process adaptation. The software-based process adaptation can be carried out in particular in a control device, as described elsewhere, and / or by means of a computer program product, as described elsewhere, which can be executed in particular on a control device.

[0034] According to a preferred aspect, the air-jet spinneret can be designed and configured to assume at least one cleaning position. The cleaning position is a position of the air-jet spinneret that differs from the operating position in which normal spinning of the air-jet spinneret takes place to produce the air-jet spun thread. To assume the cleaning position, the two housing parts of the air-jet spinneret move away from each other in a known manner, as described elsewhere, to assume an open housing position. This allows fragments of a fiber sliver to be discharged from the drafting device. This can improve the piecing process and save resources.

[0035] Before or at the latest with the start of at least one of the remaining roller pairs without the output roller pair, in particular with the start of the apron roller pair, the air-jet spinneret can be moved to the cleaning position. Subsequently, the operating roller pairs can be stopped, and the air-jet spinneret can return to the operating position to continue the piecing process, as described elsewhere, by a defined start of the drafting system. In particular, the described stopping of the output roller pair can be omitted, since the drafting system may already be stopped.

[0036] According to a preferred aspect, the drafting device can be designed and configured to separate the fiber sliver by the coordinated activation of at least one pair of rollers, in particular at least two of the roller pairs. This allows the fiber sliver to be actively separated in order to dispose of an already damaged and / or weakened fiber sliver end.

[0037] In particular, separation can be achieved in the area between a center roller pair and a pair of apron rollers, as described elsewhere. This can be achieved in particular by activating the apron roller pair, in particular by driving the bottom apron roller, before the other roller pairs of the drafting device are switched on. This allows the apron roller pair to exert tension on the fiber sliver, while the fiber sliver is clamped by at least one other roller pair, in particular arranged opposite a tension direction of the apron roller pair. This allows the fiber sliver to be severed at a weak point.

[0038] According to a preferred aspect, the drafting device can be designed and configured to coordinate the separation of the fiber sliver via a coordinated activation of at least one pair of rollers, in particular at least two pairs of rollers, with a transfer of the air-jet spinneret into the cleaning position. This makes it possible for piecing to take place in a cleaned air-jet spinneret.

[0039] The apron roller pair can be activated before the other roller pairs of the drafting system are activated to achieve severance of the fiber sliver in the area between the center roller pair and the apron roller pair, as described elsewhere. In particular, when the apron roller pair is activated, the air spinneret is moved into the cleaning position for removing the severed fiber sliver section. Cleaning can then be performed accordingly, as described elsewhere.

[0040] The process for separating the fiber sliver between the pair of output rollers and the pair of apron rollers can also be used for partial automation of the fiber sliver feed.

[0041] The preferred aspects and embodiments described here may involve a partially automated fiber sliver draw-in. So-called partial automation of the fiber sliver draw-in involves, in particular, the disposal of an "old" fiber sliver end remaining in a drafting device after a spinning interruption and the feeding of a newly drawn fiber sliver end to the air-jet spinneret for piecing. In particular, the air-jet spinneret is cleaned simultaneously or in a time-coordinated manner, as described elsewhere. A partially automated fiber sliver draw-in is possible under the conditions described here. However, not every possible fiber sliver draw-in can be partially automated. An example of a fiber sliver draw-in that cannot be (partially) automated is the insertion (in the sense of re-inserting) of a new fiber sliver.The machine operator can manually perform the fiber sliver insertion at the touch of a button. Partial automation can be implemented in a software- and process-related manner, in particular as described elsewhere. The various roller pairs can also be activated, in particular individually or in any desired combination, as described elsewhere. The preferred aspects, features, and functions of a partially automated fiber sliver insertion system can also be implemented separately from the other preferred aspects.

[0042] In particular, the sequence of warming up an output roller drive, stopping it, and then accelerating it again from zero can support piecing. Alternatively or additionally, the other roller pairs can rotate at least partially. This can keep the rubber rollers (solid rubber rollers and / or rollers with rubber coating) warm. During this time, the spinning unit may be shut down due to quality defects, particularly in a thread and / or a fiber sliver or similar.

[0043] According to a preferred aspect, the drafting device can be designed and configured to specifically adapt at least one process parameter for driving at least one of the roller pairs over a defined period of time. This allows the various advantages described elsewhere to be implemented. Alternatively, a process parameter for driving at least two of the roller pairs can be specifically adapted over a defined period of time.

[0044] In preferred embodiments, one process parameter in particular can be designed as an S-curve. In this case, the drive accelerations cannot be linear over the entire acceleration range. Rather, the drives that drive the roller pairs in particular are accelerated using a acceleration profile in the form of an S-curve. The shape of the acceleration can be adjustable in a minimum and / or maximum range. This avoids, in particular, extreme accelerations that have a negative effect on the rollers or drives and can also negatively influence the fiber sliver in the event of contact between the rollers and the sliver. The S-curve can be implemented for the thread take-off, which removes a spun thread from a spinning station and in particular feeds it to a bobbin tube or empty tube for winding the thread, in particular via a traversing device of a textile machine that produces take-up packages.Alternatively or additionally, the S-shaped pattern can also be implemented for the rollers of the drafting system. This can serve to introduce the fibers into the air-jet spinneret more moderately (i.e., defined by mass per unit time) to achieve a slow increase in fiber mass. The term "slow" here can refer in particular to a coordinated increase in fiber mass to enable coordination with a yarn take-off and, thus, coordination with the spinning speed. This can prevent the yarn from forming unevenly and / or clogging the air-jet spinneret.

[0045] In preferred embodiments, one process parameter in particular can be a decoupling. In particular, this means that the run-up profiles of the remaining roller pairs of the drafting system no longer follow the run-up profile of the output roller pair. As a result, the operation or run-up of the output roller pair, in particular the driven output bottom roller, can be temporally coordinated separately from the other roller pairs of the drafting system in their operation (relative to one another). In other words, this means that the output roller pair, in particular the driven output bottom roller, can already be rotating while the other roller pairs of the drafting system are stationary. Alternatively or additionally, drives of the other roller pairs can be operated with a different parameter, as described elsewhere. This can eliminate fluctuations in the operation of the output roller pair, in particular the output bottom roller.If the output roller pair, especially the bottom output roller, does not run up evenly, the fibers cannot be passed on in the same quantity as specified by the roller pairs of the remaining drafting system. This could lead to additional warpage or fiber buildup. This can be compensated for by individually controlling the remaining roller pairs. This makes it possible to form a uniformly shaped fiber sliver. This also enables the even delivery of fibers to the air spinneret. This also allows for the spinning of a continuously formed thread.

[0046] By individually controlling at least one drive of the roller pairs, the speed of the respective driven roller pairs or their driven lower rollers and / or upper rollers can be specifically adjusted over a defined period of time.

[0047] According to a further aspect, the drafting device can be designed and configured to form at least two support points in the run-up profile during a piecing ramp. This makes it possible for the roller pairs, whose run-up can be described in particular by the piecing ramp, to develop adapted accelerations. This also allows for the relative process parameters of the roller pairs to be adjusted to support a piecing process.

[0048] A piecing ramp can be the mathematical progression of a process parameter, for example, in an XY diagram. This allows a ramp-up from more than one point at which the process parameter changes to be described. Such a point can be described as a support point. This is, in particular, a point in the process parameter space. This creates the possibility of implementing multiple support points during the piecing ramp of at least one driven roller of the drafting system. A ramp-up with at least one driven roller of the drafting system can, in one embodiment in particular, be provided with three support points.

[0049] The term "base point" specifically refers to a variable speed that should be reached after a variable time. This change can, for example, prevent the piecing machine from tending toward a thin spot after a tie-in zone. In particular, it allows for a more flexible fiber mass configuration during piecing.

[0050] According to a preferred aspect, the drafting device can be designed and configured to maintain a defined temperature of the rollers while a spinning station is inactive. This can be achieved, in particular, by a previously described type of continued operation of at least one drive of the roller pairs. This allows the drives and / or the rubber coatings of the respective rollers to be kept at a temperature for improved operation of a drafting device. This also allows warm-up times to be reduced or even completely avoided.

[0051] According to an independent aspect, a spinning station can have at least one spinneret, in particular an air spinneret. The spinning station can have at least one yarn end preparation device. The spinning station can have at least one yarn take-off device. The spinneret and the yarn end preparation device can be arranged and designed to initiate piecing. The yarn take-off device can be arranged and designed to remove a yarn from the spinneret after a spinning process. At least one pair of rollers of a drafting device, in particular the drafting device as described elsewhere, can be switched on in a coordinated manner via the drive of the pair of rollers. This makes it possible to prevent clogging of the spinneret since, for example, a supply of fibers can take place in a controlled manner, in particular coordinated with the removal of a yarn to be formed.Alternatively or additionally, a uniform thread can be formed.

[0052] According to a preferred aspect, the yarn take-off is designed and configured, in particular, to be connected to the at least one roller pair in a coordinated manner. The at least one roller pair can have a run-up profile with a piecing ramp with at least two support points. This makes it possible to prevent clogging of the spinneret, since, for example, a supply of fibers can be controlled, in particular coordinated with the removal of a yarn to be formed. Alternatively or additionally, a uniform yarn can be formed.

[0053] The term "support point," as already described elsewhere, refers in particular to the definition of a variable speed that can be reached after a variable time. This change can, for example, prevent the piecing machine from tending toward a thin spot after a tie-in zone. This results in a more flexible fiber mass during piecing.

[0054] The piecing ramp can be a run-up ramp of a driven output roller of the output roller pair. The driven output roller can preferably be the output bottom roller. The output roller pair serves in particular to transfer the fiber sliver from a drafting system, in particular as described elsewhere, into a spinneret of a spinning station in order to spin a thread. Other structures and devices can also be involved in such a transfer, such as a pre-compressor. In other words, the driven output roller, in particular the output bottom roller, can experience several accelerations over the course of a run-up to an operating speed and also reach several speeds at different times. The corresponding reference points can be taken in a speed-over-time diagram. The run-up can begin from a complete stop.Alternatively, or at other times, the start-up can also be carried out from a warm-up mode, i.e. from a kind of basic speed.

[0055] In embodiments for the rollers of the drafting system, but also in combination with the aspects of the spinning station described here, a piecing ramp between at least two adjacent support points can have an S-shaped surface, as described elsewhere. This can also reduce breakaway torques and / or avoid high accelerations, which can have a detrimental effect on the yarn or sliver quality. This makes it possible to improve the piecing process, as described elsewhere.

[0056] Two support points are adjacent, particularly in a diagram such as a velocity-versus-time diagram, meaning they directly follow one another in the diagram's progression. "Direct" here means that there is no support point between them.

[0057] According to a preferred aspect, the spinneret can be designed and configured to assume at least one operating position and a cleaning position different therefrom, as described elsewhere. Alternatively or additionally, the yarn end preparation can be designed and configured to at least open a yarn end by means of a compressed air supply, as described elsewhere. This can improve a piecing process, as already described elsewhere.

[0058] Piecing is based, in particular, on bringing a prepared yarn end together with newly arriving fibers of the sliver in a swirl chamber of the air spinneret, as described in particular elsewhere. The timing of the yarn end return and the speeds and / or running times of the drafting device are particularly important.

[0059] According to a preferred embodiment, a piecing process can comprise at least one of the following steps: In one step, in particular an upper thread (thread on the surface of the thread-guiding package) can be caught from a package by a rotationally and / or translationally movable thread end catching device, in particular a pivotable suction nozzle that can be subjected to negative pressure, and transferred to a thread end preparation device. During this time, a thread take-off device can be opened in order to introduce the thread into the thread take-off device. The thread take-off device comprises in particular a pair of rollers with an upper and a lower roller, of which at least one roller is an active roller and the other roller is a passive roller, as described above. The active roller can be driven by an individual drive.In one step, in particular via deflection contours, the thread can be inserted into the thread take-up (also referred to as take-up) from the thread end catching device during its movement for transferring the carried thread end to the thread end preparation. A take-up can in particular be designed to take over the thread. The take-up can in particular take place in that the thread is inserted into the take-up with a thread section from the thread end catching device during its movement and is then clamped by the take-up, in particular after the thread end has been transferred from the thread end catching device to the thread end preparation. In particular, after being passed through the thread end catching device, the thread rests with a thread section on a pair of scissors and / or is arranged with a thread section or the thread end in front of a receiving opening of a dissolving tube of the thread end preparation. In particular, the thread take-up then clamps the thread.In a subsequent step, the scissors, in particular, cut the thread to create a cut thread end in preparation for a subsequent step of unraveling the thread end. According to an alternative preferred embodiment, the unraveling of the thread end can be performed without a prior thread cutting step. The thread can be cut to a defined length during the cutting step. This allows any defects in a spinning process to be removed.

[0060] Catching the yarn end and guiding it in a direction opposite to the yarn travel during the spinning process is referred to as rewinding or thread rewinding. This rewinding can occur in one step or several sub-steps, in which case we speak of a first, second, ..., xth rewind.

[0061] In one step, the (cut) thread end can be sucked into the dissolving tube by introducing a stream of compressed air and dissolved in the dissolving tube. In one step, a first return of the thread can take place, in particular by reversely rotating the take-up clamping the thread. The first return of the thread end to an outlet of a thread take-off channel of the air spinneret can be supported by introducing an air stream accompanying the thread end or the thread into a thread guide channel guiding the dissolved thread end, wherein the thread guide channel can be part of the thread end preparation and in particular can comprise or form the dissolving tube and more preferably extends to the outlet of the thread take-off channel of the air spinneret. Thus, in a first return step, the thread end can be guided through the thread guide channel to the outlet of the thread take-off channel of the air spinneret.

[0062] In one step, particularly after the first return, a thread loop can be placed in a pneumatic thread storage device, which is arranged in the thread travel direction between the air spinneret and the winding package or the winding package holder for rotatably holding the winding package, particularly between the take-up device and the winding package or the winding package holder. The thread loop can serve as compensation, since the run-up times and accelerations of at least one of a drive shaft for contact-driven driving of the winding package, a winding package, a drafting device, and / or a take-up device (take-off) can vary.Alternatively or additionally, in particular during the steps described above, an output roller of the drafting device, in particular the output bottom roller, rotates in order to comb out the fiber sliver clamped between the output bottom and top rollers and to keep the drive of the output roller, in particular the output bottom roller, and / or the rubber cover of the output roller warm.

[0063] In one step, in particular, a second return of the thread follows. This takes place in particular into a vortex chamber (also referred to as a spinning chamber) so that the unraveled thread end can be captured by the air flow. For this purpose, the air flow can be introduced into the vortex chamber of the air spinneret via the spinnerets ending in the vortex chamber, which generates a suction flow in the thread take-off channel of the air spinneret, whereby the thread end can be sucked into the thread take-off channel and transported along it to the vortex chamber of the air spinneret in such a way that the thread end is positioned in the vortex chamber between a sliver guide element and a spinning cone (also referred to as a yarn formation element) of the spinneret in order to be captured by the vortex air flow.The air spinneret is typically constructed with a two-part housing, with one housing part supporting the fiber sliver inlet and the other housing part supporting the yarn-forming element with the yarn take-off channel. The two housing parts are designed to be movable relative to each other and, when coupled, form the vortex chamber formed between the fiber sliver inlet and the yarn-forming element.

[0064] In one step, the rotating output roller, specifically the bottom output roller, is stopped. The drafting device can be started depending on input parameters, a process known as run-up.

[0065] The input parameters for the run-up, which in particular define a run-up profile, can in particular be one of an advance time, a piecing speed, a speed profile, a speed for a first stage, a duration of operation of a first stage, and / or a total run-up time of the drafting device or of the at least three roller pairs arranged therein, consisting of an input roller pair, a middle roller pair, and an output roller pair. Furthermore, a pair of apron rollers can be provided, which is arranged between the middle roller pair and the output roller pair. The pair of apron rollers can preferably follow the run-up profile of the output roller pair, particularly during run-up.

[0066] A speed profile constituting the run-up profile can, in particular, comprise at least one of four subparameters. This can be selected from a speed for a first stage, a duration of operation of a first stage, a total run-up time of the drafting system device, and a yarn take-off acceleration, which, in particular, determines the total run-up time of the yarn take-off (take-up).

[0067] In particular, during a dwell time of the yarn take-off, the yarn end can be held in the spinning chamber, which makes it possible to adjust the preparation of the drafting device in a defined manner.

[0068] In one step, the yarn take-off, in particular, runs up at a predetermined and / or input acceleration after its dwell time has elapsed. Running here refers to the driven operation of the yarn take-off. During this time, the drafting device can also run up. The yarn is thus drawn out of the spinning chamber, in particular by means of the driven yarn take-off, with the piecing process being completed, in particular, after the run-up times have elapsed.

[0069] Additionally or alternatively, a spinneret, in particular an air spinneret, can be designed and configured to assume at least one cleaning position, in particular as described elsewhere. This allows fragments of a fiber sliver to be removed from the drafting device. This can improve the piecing process and save resources.

[0070] Before or at the latest when the remaining roller pairs start, the air-jet spinneret can be moved to a cleaning position to remove the "old" fiber sliver. The roller pairs can then be stopped, and the air-jet spinneret can return to its operating position to continue the piecing process, as described elsewhere, by starting the drafting system in a defined manner. In particular, the described stopping of the output roller pair can be omitted, since the drafting system may already be stopped.

[0071] The spinneret of a spinning station can be designed and configured to discharge, in a cleaning position, fiber residues that may arise when the various roller pairs and / or drives are warmed up or when the roller pairs and / or drives are kept warm, in order in particular to prevent clogging of the spinneret.

[0072] The aspects and / or embodiments of the spinning station described here, in combination with the aspects and / or embodiments of the drafting device described elsewhere, can optimize the operation of a textile machine by preparing the fiber sliver for entry into a spinneret, as described elsewhere. Alternatively or additionally, the return of a thread end can be improved and coordinated, in particular with the feeding of a fiber sliver. The corresponding coordination of the timing of the roller pairs or their speeds and / or accelerations can be adapted to one another in such a way as to prevent excessive stretching or drawing of the fiber sliver. A damaged fiber sliver can also be replaced, whereby the entry of fibers into a spinneret of a spinning station can be optimized. This allows, in particular, the thread to be produced in a spinneret to be formed uniformly.The combination described also allows the withdrawal of a spun thread to be coordinated with the incoming fibers. This allows the thread to be formed evenly, which can have a positive effect on textiles into which the thread can be incorporated.

[0073] The spinning station can be designed independently, i.e., without combination with the drafting device described here. In this case, the take-off of a thread can be adapted to the activity of the spinneret of a corresponding spinning station.

[0074] According to an independent aspect, a method can be implemented. The method can comprise at least one step of separating a fiber sliver by the coordinated connection of at least one pair of rollers, in particular at least two pairs of rollers, of a drafting device, in particular a drafting device as described elsewhere.

[0075] The method may alternatively or additionally comprise at least the step of piecing by coordinated connection of at least two pairs of rollers of the drafting device, in particular the drafting device as described elsewhere.

[0076] Alternatively or additionally, the method may comprise at least the step of piecing by coordinatedly connecting at least one yarn take-off to a spinning station. The spinning station may, in particular, be a spinning station as described elsewhere. The piecing step may, in particular, be designed to return a yarn end to a spinneret.

[0077] The method may alternatively or additionally comprise at least the step of spinning a yarn. This step can be performed, in particular, after piecing has taken place. The spinning step can, in particular, comprise a coordinated activation of the yarn take-off and at least one pair of rollers of the drafting device, in particular a drafting device as described elsewhere.

[0078] The method can be described by the features, effects, and advantages of the textile machine, the features, effects, and advantages of the drafting device, and the features, effects, and advantages of the control device. The textile machine, the drafting device, and the method can be described by the features, effects, and advantages of the control device.

[0079] According to an independent aspect, a control device can be designed and configured to carry out a method as described elsewhere. The control device can be described by the features, effects, and advantages of the textile machine, by the features, effects, and advantages of the drafting device, and by the features, effects, and advantages as set forth with respect to the methods. The textile machine, the drafting device, and the method can be described by the features, effects, and advantages as set forth with respect to the other categories. Accordingly, the control device can be described by the features, effects, and advantages of the spinning station, as described elsewhere. The features, effects, and advantages of the control device can describe the spinning station, as described elsewhere.

[0080] According to an independent aspect, a textile machine may comprise at least one stretching device as described elsewhere. Alternatively or additionally, the textile machine may comprise a spinning station as described elsewhere. Alternatively or additionally, it may comprise a control device as described above. Alternatively or additionally, the textile machine may be designed and configured to carry out a method as described elsewhere.

[0081] The textile machine can, in particular, be an air-jet spinning machine. The textile machine can be described by the features, effects, and advantages of the drafting device, as well as by the methods. The drafting device, as well as the methods, can be described by the features, effects, and advantages of the textile machine. Accordingly, the textile machine can be described by the features, effects, and advantages of the spinning station, as described elsewhere. The features, effects, and advantages of the textile machine can describe the spinning station, as described elsewhere.

[0082] According to an independent aspect, a computer program product can be designed to carry out a method as described above when it is executed on a control device, in particular a control device as described above, of a textile machine, in particular as described above. This allows the previously described advantages and effects of the devices and methods to be realized. The devices and methods can be described by the features, effects, and advantages of the computer program product. Accordingly, the computer program product can be described by the features, effects, and advantages of the spinning station, as described elsewhere. The features, effects, and advantages of the computer program product can describe the spinning station, as described elsewhere.

[0083] A computer program product is in particular a machine-readable code stored in a memory which can control and monitor a correspondingly configured textile machine or provides corresponding instructions in this regard in order to at least partially control the textile machine when the computer program product is executed on a computing unit of a control device.

[0084] In summary, and in other words, this means that, particularly in cases where semi-automated sliver insertion is possible, for example, during shutdowns at the spinning station due to quality defects and yarn breaks, or when a spinning station has been idle for an extended period, the running times and parameters can be variably adjusted via software. Sliver insertion is performed primarily before the spinning station is started after a shutdown (quality defects, yarn breaks) or a long downtime of the spinning station. For this purpose, the rollers or roller pairs of the drafting system are operated at an adjustable speed and an adjustable running time according to their draft (variable, as they depend on the yarn count being produced).In particular, a new portion of the fiber sliver is drawn and delivered toward the spinneret, while the old fiber sliver, including any irregularities, is removed. During this time, the spinning station moves into a cleaning position. This allows excess fibers created during the fiber sliver draw-in process to be more effectively removed. This can prevent fiber clogging, particularly in a spinning station. The cleaning position is particularly variable and includes at least two different variants.

[0085] In a first variant, the spinning pressure can be switched off and the spinneret, in particular, does not open. The fibers can then be drawn into a suction system, in particular either an upper and / or a lower suction system.

[0086] In a second variant, the spinning pressure can be activated and the spinneret can be opened. The fibers are drawn through the fiber inlet and sucked out below the spinneret.

[0087] Alternatively or additionally, partial automation of the sliver draw-in can be achieved by switching on, for example, an apron drive during the warm-up of the output roller pair, in particular the output bottom roller. This allows the sliver to be separated in a so-called main drafting zone. For this purpose, the sliver draw-in is not carried out before the start of the piecing process, but rather after a warm-up. The sliver draw-in can take place in particular between the step of combing out and / or keeping warm an output roller drive and / or a rubber coating of at least one roller and a second return, as described elsewhere. The cleaning position takes place in particular in a step of a second return. In this case, the spinneret is briefly opened, in particular at the start of the return of the thread. In this case, the spinning pressure is already on, in particular during this part of the piecing process.This results in the second variant of the cleaning position, especially at a later time.

[0088] The fiber sliver draw-in depends primarily on the setting of a drafting device, i.e., on the set distance between the roller pairs, whereby the running time can be variably adjusted. The distance between the roller pairs can, in particular, be variably adjustable and support the drawing of the fiber sliver.

[0089] Alternatively or additionally, the control device or the machine-readable code executed thereon can control the activity of a spinning station, in particular a spinneret and / or a yarn end preparation device, in particular a compressed air supply for opening a yarn end and / or an opening tube for opening a yarn, in a coordinated manner, in particular together with at least one drivable roller, in particular a bottom roller of a drafting system. In this case, several support points can be configured for at least one drivable roller, in particular at least one bottom roller, in a start-up, as described elsewhere. The drivable roller can be an output roller, in particular an output bottom roller.

[0090] In the following, embodiments of the invention are described in more detail with reference to figures, which show schematically and by way of example: Fig. 1 is a schematic representation of a piecing process; Fig. 2A is a view of a fiber sliver layer in an embodiment of a drafting device after a shutdown; Fig. 2B is a view of the start of the warm-up of the apron bottom roller and / or output bottom roller in an embodiment of a drafting device, wherein the fiber sliver is separated; Fig. 2C is a view of a fiber sliver layer after the end of the warm-up of the apron bottom roller / output bottom roller in an embodiment of a drafting device; Fig. 3A is a view of a first cleaning position in an embodiment of a drafting device; Fig. 3B is a view of a second cleaning position in an embodiment of a drafting device; Fig. 4 is a schematic representation of a piecing ramp of an output bottom roller and a thread take-off; Fig. 5 is a schematic representation of a piecing ramp with a support point;Fig. 6 is a schematic representation of a piecing ramp with S-shaped cross-section; Fig. 7 is a schematic representation of a piecing ramp with one support point; and Fig. 8 is a schematic representation of a piecing ramp with three support points.

[0091] The same reference symbols are used for elements and structures with the same function and / or similarity.

[0092] Fig. 1 shows a schematic representation of a piecing process 100 in a textile machine, in particular an air-jet spinning machine. In step 1, a thread end of a thread deposited on a winding bobbin (also referred to as the upper thread) can be captured. In this step 1, the thread end can be captured by a movable thread end catching device such as a suction nozzle. Meanwhile, a thread take-off formed by a pair of rollers can be opened to allow the thread to be introduced into the thread take-off.

[0093] In a step 2 of accommodating a thread section, the thread can be inserted into the thread take-up, a so-called take-up, via deflection contours during the movement of the thread end catching device. The take-up can be designed in particular to receive the thread. In particular, the thread is arranged, in particular at the end of the movement of the thread end catching device, in a cutting area of ​​a pair of scissors and / or in front of an opening of a dissolving tube of a thread end preparation device. The thread take-up clamps the thread, in particular after the thread end has been arranged as described above.

[0094] In step 3, the thread can be cut using scissors. A defined length of thread can be cut off.

[0095] In a step 4 of dissolving the thread end, the thread end can be dissolved by introducing a compressed air flow into a dissolving tube.

[0096] In a step 5 of a first return of the thread to an exit of a thread take-off channel of an air spinneret, a first return of the thread can be assisted by reversing the take-up clamping the thread and by introducing an air stream accompanying the thread end or the thread into a thread guide channel guiding the opened thread end. The thread guide channel can be part of the thread end preparation and, in particular, can comprise or form the opening tube and, more preferably, extends to the exit of the thread take-off channel of the air spinneret. The spinning pressure can be used for air-accompanying transport within the thread take-off channel; alternatively or additionally, the thread can be blown further within the thread guide channel by a supply of compressed air.

[0097] In a step 6 of laying a thread loop, in particular after step 5 of the first return, the step 6 of laying the thread loop in a pneumatic thread storage device can take place, which is arranged in the thread travel direction between the air spinneret and the winding package or the winding package holder for rotatably holding the winding package, in particular between the take-up device and the winding package or the winding package holder. The thread storage device can serve as compensation, since the run-up times and accelerations of at least one of a drive shaft, a winding package, a drafting device 101, and / or a take-up device can differ.

[0098] In a step 7 of combing and keeping warm, in particular during the previously described steps 1 to 6, a pair of output rollers rotates by driving the output bottom roller 26 in order to comb out the fiber sliver 31 arranged between the output rollers and to keep the output bottom roller drive 36 and / or the rubber covering of the output rollers warm.

[0099] In the case of a semi-automated fiber sliver draw-in, the above step 7 in particular can be adapted. In other words, particularly after step 6 or with step 7, the remaining roller pairs of the drafting system 101 (input roller pair, middle roller pair(s), and, if present, apron roller pair) are switched on in a defined manner to start a defined drawing-in and drawing of the fiber sliver. Before or at the latest with the start of the remaining roller pairs, the air-jet spinneret can be moved into a cleaning position (see the two variants described elsewhere) in order to remove the "old" fiber sliver. Subsequently, the roller pairs can be stopped, and the air-jet spinneret, in particular, returns to the operating position to continue the piecing process, as described elsewhere, in particular by a defined start of the drafting system 101 (see step 9).Here, the stopping of the output bottom roller drive 36 described elsewhere can be omitted, since the roller pairs of the drafting device 101 can already be stopped.

[0100] This can be supplemented by activating the apron roller pair, in particular by driving the apron bottom roller, before switching on the remaining roller pairs of the drafting device 101, in order to achieve a separation of the fiber sliver 31 in the area between the center roller pair and the apron roller pair. With the switching on of the apron roller pair, in particular, the air spinneret is moved into the cleaning position for removing the separated fiber sliver section.

[0101] Additionally or alternatively, the speeds of the respective driven rollers of the respective roller pairs, in particular the driven bottom rollers, can be specifically adjusted over a defined period of time. In this case, the operation of a roller can, in particular, have at least two support points during a ramp-up in a piecing ramp or in a ramp-up of a ramp-up profile of the roller. This is described in detail elsewhere.

[0102] In step 8, a second return is performed, in particular, by a second return of the yarn. This takes place, in particular, into a vortex chamber (also referred to as a spinning chamber) so that the yarn end can be captured by the air flow.

[0103] In step 9, stopping the output roller pair, the rotation of the output rollers or the output roller pair is stopped. The drafting device 101 can then be started depending on input parameters.

[0104] The input parameters for the run-up, which define the run-up profile, can be, in particular, one of an advance time, a piecing speed, a speed profile, a speed for a first stage, a duration of operation of a first stage, and / or a total run-up time of the drafting device 101. The driven apron bottom roller 24, center bottom roller 22, and / or input bottom roller 20 can follow the output bottom roller 26 during run-up.

[0105] A speed profile constituting the run-up profile can, in particular, have at least one of four subparameters. These can be selected from a speed for a first stage, a duration of operation of a first stage, a total run-up time of the drafting system device 101, and a yarn take-off acceleration, which, in particular, determines the total run-up time of the yarn take-off.

[0106] During a dwell time of the yarn take-off, the yarn end can be held in the spinning chamber, which makes it possible to adjust the preparation of the drafting device 101 in a defined manner.

[0107] In a step 10 of a dwell for a dwell time, in particular the thread take-off runs up at the end of its dwell time according to a predetermined and / or input acceleration.

[0108] In a step 11 of a running operation of the yarn take-off, the drafting device 101 also runs up, in particular during this time. Running here refers to the driven operation of the yarn take-off. After being connected to the fiber sliver 31, the yarn is drawn from the spinning chamber by means of the driven yarn take-off for continuous spinning of the yarn, with the piecing process being completed, in particular, after the run-up times have elapsed.

[0109] Fig. 2Ashows a view of a fiber sliver layer in one embodiment of a drafting device 101 after the illustrated lower rollers 20, 22, 24, 26 of roller pairs have been switched off, each of which is composed of one of the lower rollers 20, 22, 24, 26 and a respectively associated upper roller in order to transport the intermediate fiber sliver 31 in a closed state during rotation of the roller pairs driven by the illustrated lower rollers 20, 22, 24, 26. In particular, an input lower roller 20 of an input roller pair, a middle lower roller 22 of a middle roller pair, an apron lower roller 24 of an apron roller pair, and an output lower roller 26 of an output roller pair are shown in a row, which are components of the drafting device 101. The drafting device 101 is attached to a support 12 via a locking device 16.The input bottom roller 20 is driven in particular by an input bottom roller drive 30. The center bottom roller 22 is driven in particular by a center bottom roller drive 32. The apron bottom roller 24 is driven in particular by a belt bottom roller drive 34. The output bottom roller 26 is driven in particular by an output bottom roller drive 36. An apron 28, which can also be guided around an apron bridge 29 to build up tension in the aprons 28, runs around the apron bottom roller 26. The bottom rollers 20, 22, 24, 26 can be adjusted in their relative position to one another via an adjustment device 18.The lower part of the drafting device 101 shown here can be connectable via a top roller carrier (not shown) which carries the top rollers (not shown) of the respective roller pairs, wherein the top rollers form passive rollers due to the lack of their own drive.

[0110] Fig. 2B shows a view of a start of the warm-up of the apron bottom roller 24 and / or the output bottom roller 26 in an embodiment of the drafting device 101, wherein the fiber sliver 31 is separated in a separation area 25.

[0111] Fig. 2C shows a view of a fiber sliver layer after the end of the warm-up of the apron bottom roller 24 and / or output bottom roller 26 in an embodiment of the drafting device 101. The separating region 25 can be located in a region of a compressor which is arranged upstream of the apron bottom roller 24.

[0112] During a step 7, as described in relation to the Fig. 1As described above, the spinning station with the cleaning nozzle can be moved into the cleaning position. This allows excess fibers that are created during warm-up to be removed more effectively without causing fiber blockage, particularly in a spinneret 40. The cleaning position is particularly variable and can have two different variants, as shown in the Figs. 3A and 3B shown and described below.

[0113] Fig. 3Ashows a view of a first cleaning position in an embodiment of the drafting device 101. In this case, a fiber sliver 31 is guided between an output top roller 27 and an output bottom roller 26 and transported by the rotation of the rollers. In this case, a spinning pressure within the spinneret 40 can be switched off, and the spinneret 40, formed from two housing parts, can be closed, i.e., cannot open. As a result, the fibers of the fiber sliver 31 or its fragments 14 can reach either the upper suction 13 or the lower suction 15, which are arranged in the region of the output roller pair formed by the output bottom roller 26 and output top roller 27 and are assigned to them, and can thus be suctioned away.

[0114] Fig. 3Bshows a view of a second cleaning position in an embodiment of the drafting device 101. The spinning pressure can be switched on and the spinneret 40 can be opened by a relative movement in the direction of the double arrows of one of the two housing parts, which carries the spinning cone 42 of the spinneret 40, relative to the other housing part, which carries the fiber inlet 21. The fibers of the fiber sliver 31 or its fragments 14 are sucked in particular through the fiber inlet 21 and via a fiber suction device 23 communicating with the spinning chamber in the open position of the spinneret 40, i.e. in a position of the spinning cone 42 at a distance from the fiber inlet 21 (not shown). After completion of step 7 of stopping the output bottom roller drive 36 and the apron bottom roller drive 34, the spinning station returns in particular to its normal spinning position (spinning pressure on, spinneret 40 closed as in Figure 3Ashown). The next process steps then take place as described elsewhere. This is followed by the second return 8 of the thread, and the drafting device 101 or its lower rollers 20, 22, 24, 26 is / are accelerated using the parameters described elsewhere in step 9. For this purpose, the parameters in step 9 are particularly adapted so that they can be used to transport the fibers to the spinneret 40. For this purpose, significantly longer times are entered. Fig. 4 The piecing ramp for this case is shown schematically (not to scale).

[0115] Fig. 4shows a schematic representation of a piecing ramp 420 of a driven output bottom roller 26 compared to a piecing ramp 410 of a driven roller of a yarn take-off. The time 415 is plotted in milliseconds (ms) on the X-axis. The speed of the output bottom roller 26 or the driven roller of the yarn take-off is plotted on the Y-axis, approximately in units of revolutions per minute. In one time range (negative time range), in particular, a fiber sliver draw-in 400 is realized. In this case, the output bottom roller 26 is already being controlled, which is why a piecing ramp 420 is already forming at this time. The yarn take-off is still stopped at a zero time (selected as the starting point for the speed increase of the driven output bottom roller 26 in a piecing ramp 420).This enables the following: In particular, the initial start-up of the apron bottom roller drive 34 and the output bottom roller drive 36 occurs without the fiber sliver 31 in this first time range. This prevents, in particular, the breakaway torque from having an effect in this zone. Furthermore, in particular, the piecing process occurs with the drafting device 101 already running, which can reduce stress in the fiber sliver 31.

[0116] Fig. 5shows a schematic representation of a piecing ramp 530 with a support point 550. The speeds 505 are plotted against time 515. This results in piecing ramps 510 for a yarn take-off roller drive or for the driven yarn take-off roller, a piecing ramp 520 for an output bottom roller drive 36 or for the driven output bottom roller 26, and a piecing ramp 530 with a support point for an apron bottom roller drive 34 or for the driven apron bottom roller 24. A first speed stage 551 is formed upstream of a first support point 550. The yarn take-off can remain in a dwell time 540. The dwell time 540 of the yarn take-off runs in particular in such a way that the yarn end is held in the spinning chamber and enables the preparation of the drafting device 101 to be adjusted. This is in step 10 in the Fig. 1shown and described in this regard. The yarn take-off ramps up, in particular, upon expiration of its dwell time 540 according to the entered acceleration, during which the drafting device 101 also ramps up. The yarn is drawn out of the spinning chamber, in particular, and the piecing process is completed, in particular, after the ramp-up times have elapsed. The total ramp-up time 560 of the drafting device 101 is indicated, as is the total ramp-up time 570 of the yarn take-off.

[0117] Fig. 6shows a schematic representation of a piecing ramp 630 for an output bottom roller drive or for the driven output bottom roller 26 with S-curve 610, 620 as an example of a process parameter. In this diagram, the speed 605 is plotted over time 615. The acceleration of the drives (of the bottom rollers 20, 22, 24, 26) is not exclusively linear, but rather with an S-curve, which can be adjusted. This allows extreme accelerations to be avoided. The S-curve 610, 620 can be implemented both for the yarn take-off and for the drafting device 101 or its driven bottom rollers 20, 22, 24, 26.

[0118] Fig. 7shows acceleration ramps (speed 705 over time 715) of the drafting device 101, whereby only one support point 725 can be formed during acceleration, for an acceleration ramp 710 of a thread take-off roller drive. An acceleration ramp 720 of an output bottom roller 26 is shown, as is the acceleration ramp 730 of an input bottom roller 20. The corresponding statements of Fig. 5 continue here.

[0119] Fig. 8 shows acceleration ramps (speed 705 over time 715) of the drafting device 101, wherein, as an example, three support points 725, 735, 745 can be formed during acceleration in an acceleration ramp 720 of an output bottom roller 26. The corresponding statements of the Fig. 5 and 7Continue here. The three support points 725, 735, and 745 specifically represent a setting of a variable speed 705, which can be reached after a variable time 715. This change can, for example, prevent the piecing unit from leaning toward a thin spot after the binding zone. This results in, in particular, a more flexible fiber mass configuration during piecing.

[0120] "May" refers in particular to optional features of the invention. Accordingly, there are also further developments and / or embodiments of the invention that additionally or alternatively comprise the respective feature(s).

[0121] If necessary, isolated features may also be selected from the combinations of features disclosed here and used in combination with other features to define the subject matter of the claim, dissolving any structural and / or functional connection that may exist between the features. List of reference symbols

[0122] 1 Catching a thread end of a thread 32 Center lower roller drive 34 apron bottom roller drive 2 Placing a section of the thread in the take-up 36 Output bottom roller drive 40 spinneret 3 Cutting the thread with scissors 42 spinning cone 100 Piecing process 4 Dissolving the thread end 101 Drafting device 5 first return of the thread 400 Sliver feed 6 Laying a thread loop 410 Piecing ramp for a thread take-off drive 7 Combing and keeping warm 8 second repatriation 405 speed 9 Stopping the output bottom roller 415 Time 10 Residence time 420 Piecing ramp for an output bottom roller drive 11 Running time of the thread take-off 12 carrier 505 speed 13 upper suction 510 Piecing ramps for a thread take-off drive 14 fragments 15 lower suction 515 Time 16 locking device 520 Piecing ramp 18 Adjustment device 530 Piecing ramp with one support point 20 Input bottom roller 21 Fiber inlet 540 Residence time 22 Center lower roller 550 single base 23 Fiber extraction 551 Speed ​​level 24 apron bottom roller 560 Total run-up time of the drafting device 25 Separation area 26 Output bottom roller 570 Total run-up time of the thread take-off 27 Output top roller 28 Straps 605 speed 29 Strap bridge 610, 620 S-grinding 30 Input bottom roller drive 615 Time 31 Sliver 630 Piecing ramp of a Output bottom roller with S-grinding 720 Run-up ramp of an output bottom roller 705 speed 730 Run-up ramp of an input bottom roller 710 Acceleration ramp of a thread take-off roller drive 725, 735, 745 Bases 715 Time

Claims

1. A drafting device (101) for a textile machine, in particular an air-jet spinning machine, wherein the drafting device (101) comprises a plurality of roller pairs that can be driven differently from one another, wherein the roller pairs are designed and arranged to guide a fiber sliver (31) between a respective upper roller and a lower roller of the respective roller pairs during their rotational operation in order to draw the fiber sliver (31); and wherein the drafting device (101) is designed and arranged to carry out a piecing process (100) after separation of the fiber sliver (31) in the drafting device (101), characterized in that the drafting device (101) is designed and configured to connect at least two pairs of rollers in a defined manner via their drive in the piecing process (100).

2. Drafting device (101) according to claim 1, characterized in thatat least two roller pairs for a defined addition are selected from the list of the following roller pairs: - input roller pair, - middle roller pair and / or - apron roller pair.

3. Drafting device (101) according to one of claims 1 or 2, characterized in that a spinneret (40), in particular an air spinneret, is designed and arranged to assume at least one cleaning position.

4. Drafting device (101) according to one of the preceding claims, characterized in that the drafting device (101) is designed and configured to separate the fiber sliver (31) by a coordinated addition of at least one pair of rollers, in particular by a coordinated addition of at least two pairs of rollers.

5. Drafting device (101) according to one of the preceding claims, characterized in thatthe drafting device (101) is designed and configured to coordinate the separation of the fiber sliver (31) by means of a coordinated addition of at least one pair of rollers, in particular by means of a coordinated addition of at least two pairs of rollers, with a transfer of a spinneret (40) into a cleaning position.

6. Drafting device (101) according to one of the preceding claims, characterized in that the drafting device (101) is designed and configured to specifically adapt at least one process parameter for driving at least one of the roller pairs, in particular at least two of the roller pairs, over a defined period of time (715).

7. Drafting device (101) according to one of the preceding claims, characterized in thatthe drafting device (101) is designed and configured to form at least two support points (725, 735, 745) in a run-up profile for the defined driving of at least one of the roller pairs during a piecing ramp.

8. Drafting device (101) according to one of the preceding claims, characterized in that the drafting device (101) is designed and configured to maintain a defined temperature of the drive of one of the roller pairs and / or a rubber covering of the rollers of one of the roller pairs, in particular while the spinning station is inactive.

9. Spinning station comprising - at least one spinneret (40), in particular an air spinneret; - at least one yarn end preparation; and - at least one yarn take-off; wherein the spinneret (40) and the yarn end preparation are arranged and designed to initiate piecing; and wherein the yarn take-off is arranged and designed to remove a yarn from the spinneret after a spinning process; characterized in that at least one drivable pair of rollers of a drafting device (101), in particular the drafting device (101) according to one of claims 1 to 8, is connected in a coordinated manner via the drive of the pair of rollers.

10. Spinning station according to claim 9, characterized in that the thread take-off is designed and arranged in such a way as to be connected to the at least one pair of rollers in a coordinated manner, wherein a run-up profile of the at least one pair of rollers has a piecing ramp (710, 720, 730) with at least two support points (725, 735, 745).

11. Spinning station according to one of claims 9 or 10, characterized in that the spinneret (40) is designed and configured to assume at least one operating position and a cleaning position different therefrom; and - the thread end preparation is designed and configured to at least open a thread end by means of a compressed air supply.

12. Method (100) comprising at least one of the following steps: - separating a fiber sliver by the coordinated addition of at least one pair of rollers, in particular of at least two pairs of rollers, of a drafting device (101), in particular a drafting device (101) according to one of claims 1 to 8; - piecing by the coordinated addition of at least two pairs of rollers of the drafting device (101), in particular the drafting device (101) according to one of claims 1 to 8; and - piecing by the coordinated addition of at least one thread take-off of a spinning station, in particular a spinning station according to claim 9, in particular to return a thread end, in particular into a spinneret;- spinning a thread, in particular after piecing has taken place, comprising a coordinated connection of thread take-off and at least one pair of rollers of the drafting device (101), in particular the drafting device (101) according to one of claims 1 to 8; 13. Control device designed and configured to carry out a method (100) according to claim 12.

14. A textile machine comprising at least one of the following: - a drafting device (101) according to one of claims 1 to 8; - a spinning station according to one of claims 9 to 11; and - a control device according to claim 13; and / or wherein the textile machine is designed and configured to carry out a method (100) according to claim 12.

15. Computer program product designed to carry out a method (100) according to claim 12 when it is carried out on a control device, in particular a control device according to claim 13, of a textile machine, in particular a textile machine according to claim 14.