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 apparatus. The invention relates to a textile machine. The invention relates to a computer program product.

Drafting devices are known in the prior art. They are used in particular in textile machines, and in particular in air-jet spinning machines for air-jet spinning. In air-jet spinning, a sliver, also referred to as a drawing frame sliver, is drawn according to the yarn count to be achieved by means of a drafting device, in particular a 4-roller drafting device, and is fed to a spinneret. The spinneret is in particular a functional device of a spinning station. Inside the spinneret, a portion of the fed fibers can be wound around the parallel fiber core by means of a rotational flow. In particular, this yields the air-jet yarn-specific yarn structure of a yarn core consisting of parallel fibers and wrapping fibers, which lie against the yarn core at a certain angle and can ensure the strength of the yarn.

If individual rollers of the drafting device stand still for a longer period of time, the sliver may become dented over time. In the same way, if the textile machine and/or the drafting device is stopped frequently, the sliver can be a possible source of error for the air-jet spinning process. In the event of a thread breakage, thread cut, or sliver breakage, piecing can be provided to resume the spinning of a thread. The indentation in the sliver can make piecing difficult and lead to a weak point in a thread made therefrom.

Spinning stations which can be used for piecing in addition to spinning a thread are known in the prior art. A thread end is prepared for piecing, for example after a thread breakage, so that fibers can be reattached to the thread in order to continue spinning the thread. This makes it possible to continue a spinning process, for example after a thread breakage has occurred. In air-jet spinning machines according to an exemplary embodiment, piecing is based in particular on bringing together an unraveled thread end in the vortex chamber of the air-jet spinneret and newly arriving fibers of the sliver. The timing of a thread end return and the speeds of the drafting device as well as their times are in particular important for piecing a thread. Piecing can lead to irregularities in the thread, in particular if the timing is incorrect, which can have a negative effect on the yarn quality.

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

The object is achieved by a drafting device having the features of claim 1. The object is achieved by a spinning station having the features of claim 9. The object is furthermore achieved by a method having the features of claim 12. The object is achieved by a control apparatus having the features of claim 13. The object is furthermore achieved by a textile machine having the features of claim 14. The object is achieved by a computer program product having the features of claim 15.

Advantageous embodiments of the invention are the subject matter of the dependent claims.

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

A drafting device can be designed for a textile machine. In particular, the textile machine can be an air-jet spinning machine. The drafting device can have a plurality of roller pairs that can be driven differently from one another. The roller pairs can be designed and arranged to guide a sliver between a top roller and a bottom roller of the respective roller pairs during operation in order to stretch the sliver. The drafting device can be designed and configured to carry out a piecing process after the sliver has been severed in the drafting device. The drafting device can be designed and configured to engage at least two roller pairs via their drive in a defined manner during the piecing process. This means that the roller pairs can in particular be controlled in a defined manner and correspondingly be operated in operating modes different from one another. Different operating modes can differ 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 not accelerate (linearly) from a full stop, i.e., from a standstill, to an operating state during a piecing process. This can also eliminate the need to warm up the rollers from a standstill mode. Rather, the rollers can be kept warm. This can improve spinning, in particular piecing, and the thread can be made more uniform, which can reduce the resources required for a spinning process.

A drafting device can also have a drafting system and/or be referred to as such. In particular, such a drafting system can have a number of roller pairs. In particular, these roller pairs can respectively have at least one active roller, which can be referred to as an active roller or as a 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 thereby. In particular, the non-active roller is a passive roller. A contact pressure can be formed between the two rollers in order to make possible the transfer of force between the drive roller as the active roller and the following roller as the passive roller.

A sliver (also referred to as a fiber composite) is understood to be a band made of longitudinally parallelized individual fibers that are held together by static friction. However, the fibers are not yet joined to form a thread, as in particular described elsewhere. Inside a spinneret, a portion of the fed fibers from the sliver can, by means of a rotational flow, be wound around a fiber core, which is made of parallel fibers and forms the yarn core. This in particular yields the air-jet yarn-specific yarn structure of a yarn core made of parallel fibers and wrapping fibers, which wrap around the yarn core at a certain angle 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, or the spinneret can be referred to as a spinning chamber.

A piecing process can be a method and/or a method step in which a sliver end is connected to a thread end in order to be able to continue the spinning process. In particular, piecing is based on bringing together an unraveled thread end in the spinning chamber/spinneret and newly arriving fibers of the fed sliver end. The timing of the returns, in particular of the unraveled thread end, and the speeds and/or the running times of the drafting device, in particular for feeding fibers in a corresponding quantity that is advantageous for spinning, in particular piecing, can take place as described below.

In a spinning machine, in particular an air-jet spinning machine, piecing is based in particular on bringing together a prepared thread end, in particular in a vortex chamber of the spinneret, which forms an air-jet spinneret, and newly arriving fibers of the sliver. 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 arrangement into an almost completely, and preferably completely, longitudinally parallelized arrangement. An almost completely longitudinally parallelized arrangement is an arrangement of fiber ends in which not all fiber ends have been longitudinally parallelized in the course of the unraveling process for longitudinal parallelization of the fiber ends; instead, a tolerance-related small portion of the fiber ends have not undergone longitudinal parallelization for process-related reasons.

For the piecing process, the timing of the thread end return and the speeds and/or the running times of the drafting device for inter alia feeding the sliver end are in particular important. 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 take-up bobbin) can be caught by a take-up bobbin 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 can be transferred to a thread end preparer. In the meantime, a thread take-off can be opened in order to insert the thread into the thread take-off. In particular, the thread take-off comprises a roller pair with an upper and a bottom 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-off (also referred to as a take-up) by the thread end catching device in the course of its movement to transfer the entrained thread end to the thread end preparer. In particular, the take-up can be designed to take the thread. In particular, the taking can take place in that the thread, in the course of its movement, is inserted by a thread section by the thread end catching device into the take-up and is then clamped thereby, in particular after the thread end has been transferred from the thread end catching device to the thread end preparer. In particular, after being moved by the thread end catching device, the thread lies with a thread section on scissors and/or is arranged with a thread section or the thread end in front of a receiving opening of an unraveling tube of the thread preparer. In particular, the thread take-off subsequently clamps the thread. In a subsequent step, in particular the scissors 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 thread end can be unraveled without a previous step of cutting the thread.

Catching the thread end and guiding it in a direction opposite the thread running direction during the spinning process is referred to as a return or thread return. In particular, the return can take place in one step or a plurality of substeps, wherein a first, second, . . . , x-th return is then mentioned.

In one step, the (cut) thread end can be sucked into the unraveling tube and unraveled by introducing a flow of compressed air. In one step, a first return of the thread can take place by rotating back the take-up that clamps the thread. The first return of the thread end to an outlet of a thread take-off channel of the air-jet spinneret can be supported by introducing an air flow accompanying the thread end or the thread into a thread guide channel guiding the unraveled thread end, wherein the thread guide channel can be part of the thread end preparer and in particular can comprise or form the unraveling tube and can furthermore preferably extend to the outlet of the thread take-off channel of the air-jet spinneret. This allows the thread end to be guided through the thread guide channel to the outlet of the thread take-off channel of the air-jet spinneret in a first return step.

In one step, in particular after the first return, a thread loop can be placed in a pneumatic thread storage, which is arranged in the thread running direction between the air-jet spinneret and the take-up bobbin or the take-up bobbin holder for rotatably holding the take-up bobbin, in particular between the take-up and the take-up bobbin or the take-up bobbin holder. The thread loop can serve as compensation since the ramp-up times and accelerations of at least one of a drive shaft for contact-driving the take-up bobbin, a take-up bobbin, a drafting device, and/or a take-up can be different. 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 sliver clamped between the output bottom and top rollers and in order to keep warm the drive of the output roller, in particular the output bottom roller, and/or the rubber lining of the output rollers.

In one step, in particular a second return of the thread follows. In particular, this takes place right into a vortex chamber (also referred to as a spinning chamber) so that the unraveled thread end can be caught by the air flow. For this purpose, the air flow can be introduced into the vortex chamber of the air-jet spinneret via the spinnerets ending in the vortex chamber, which air flow generates a suction flow in the thread take-off channel of the air-jet spinneret, whereby the thread end can be sucked into the thread take-off channel and transported along to the vortex chamber of the air-jet 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-forming element) of the spinneret in order to be caught by the vortex air flow. In particular, the air-jet spinneret is usually constructed with a two-part housing, with one housing part bearing the sliver inlet and the other housing part bearing the yarn-forming element with the thread take-off channel. The two housing parts are designed to move relative to one another and, in a coupled state, form the vortex chamber formed between the sliver inlet and the yarn-forming element.

In one step, the rotating output roller, in particular output bottom roller, is stopped. The drafting device can be started depending on input parameters, which is referred to as ramping up.

The input parameters for the ramp-up, which in particular define a ramp-up profile, can in particular be one of a lead time, a piecing speed, a speed profile, a speed for a first stage, a duration of operating a first stage, and/or a total ramp-up time of the drafting device or of the at least three roller pairs arranged therein, comprising an input roller pair, a center roller pair, and an output roller pair. Furthermore, an apron roller pair can be provided, which is arranged between the center roller pair and the output roller pair. The apron roller pair can preferably follow the ramp-up profile of the output roller pair, in particular while ramping up.

A speed profile that makes up the ramp-up profile can in particular have at least one of four sub-parameters. This sub-parameter can be selected from a speed for a first stage, a duration of operating a first stage, a total ramp-up time of the drafting device, and a thread take-up acceleration, which in particular determines the total ramp-up time of the thread take-up.

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

In one step, the thread take-off in particular ramps up at the end of its dwell time in accordance with a specified and/or entered acceleration. Running is understood herein to mean the driven operation of the thread take-off. In the meantime, the drafting device can also ramp up. The thread is pulled out of the spinning chamber by means of the thread take-off after connection to the sliver for continuous spinning of the thread, wherein the piecing process is completed in particular after the ramp-up times have elapsed.

According to a preferred aspect, it can be provided that at least two roller pairs for a defined engagement are selected from the list of the following roller pairs: an input roller pair, a center roller pair, and/or an apron roller pair.

The remaining roller pairs of the drafting device (input roller pair, center roller pair(s), and/or apron roller pair) can preferably be engaged in a defined manner in order to start a defined drawing-in and stretching of the sliver. In this context, one of the mentioned roller pair types can be referenced as the remaining roller pairs. In particular, the engagement can occur after a step of a first return. Furthermore in particular, the engagement can follow placement of a thread loop. Alternatively or additionally, the engagement can take place during or after a step of combing out the sliver. Alternatively or additionally, the engagement can take place during or after a step of keeping warm a drive of the output roller pair, in particular a drive of the output bottom roller, and/or the rubber lining of at least one of the output rollers.

Alternatively or additionally, at least one of the aforementioned roller pairs, in particular an output roller pair, and in particular an output bottom roller, can be engaged in a defined manner with a ramp-up of a thread take-off. In particular, a defined engagement of at least one of the roller pairs, as also described elsewhere, can take place in such a way that a sliver is fed to a spinning station in a coordinated manner while a thread end is unraveled and/or while it is part of a first and/or a second return and/or an x-th return. At least the ramp-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 explanations, and repetition is omitted for reasons of readability and compactness.

In particular, a drafting device can have an apron that revolves around an apron roller of an apron roller pair, in particular an apron bottom roller. One of the apron rollers, the apron bottom roller or the apron top 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 circumferential speeds of roller pairs arranged directly one after the other in the direction of sliver transport make a defined stretching of the sliver between these two roller pairs possible.

According to a preferred embodiment, it can be provided that, while the output bottom roller pair rotates for combing out the sliver and/or keeping warm, in particular during the steps described elsewhere from catching of an upper thread end to a first return, the output roller drive for driving the output rollers is left in operation and the apron roller drive for driving the apron rollers can be engaged, wherein in particular the apron bottom roller is actively driven while the drives of the remaining roller pairs, such as the input roller pair drive and/or the center roller pair drive, are in particular stationary. This allows the sliver to be severed between the center roller pair and the apron roller pair, allowing the severed piece of sliver to be discharged from the drafting device by the rotating apron and output rollers.

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

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 first start-up of the apron roller motor, in particular the apron roller drive, and the output roller drive to take place without a sliver in this region. This can prevent the breakaway torque from having an effect in this zone. This means that the breakaway torque cannot influence the sliver and therefore cannot affect the thread quality or yarn quality. Alternatively or additionally, the piecing can be performed in a drafting device that has already started up.

The preferred aspects and embodiments described here and elsewhere can reduce or completely prevent minimally different starting times of the individual drafting system roller drives, as well as slight deviations of target/actual parameters, such as target/actual speed(s), in particular of the output roller drive, furthermore in particular of the output bottom roller drive. In addition, the factors mentioned elsewhere as being disadvantageous can in particular be improved, e.g., by avoiding increased pressure forces on the drafting system rollers. This can reduce or completely prevent incorrect drafting for piecing. This can also reduce or prevent the faltering acceleration of the apron roller pair, which was in particular noticeable beforehand in high-speed camera shots.

Here and elsewhere, this refers in particular to a reduction or decrease of an event or risk selected from a probability of occurrence of a frequency of occurrence.

The preferred aspects and embodiments described here and elsewhere make it possible to circumvent different breakaway torques, in particular of the apron roller pair, and/or to circumvent an (initial) target/actual speed deviation, in particular of the output roller drive, with different drafting system settings by adjusting the process by software. The process can be adjusted by software in particular in a control apparatus, as described elsewhere, and/or by means of a computer program product, as described elsewhere, which can be executed in particular on a control apparatus.

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 different from the operating position, in which normal spinning operation of the air-jet spinneret takes place to produce the air-jet spun thread. In order to assume the cleaning position, the two housing parts of the air-jet spinneret move away from one another in a known manner, as described elsewhere, to assume an open housing position. This allows fragments of a sliver to be removed from the drafting device. As a result, the piecing process can be improved, and resources can be saved.

The air-jet spinneret can be moved to the cleaning position 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. Subsequently, the operated roller pairs can be stopped, and the air-jet spinneret can resume the operating position in order to continue the piecing process, as described elsewhere, by starting the drafting device in a defined manner. In particular, the described stopping of the output roller pair can be omitted since the drafting device can already be stopped.

According to a preferred aspect, the drafting device can be designed and configured to sever the sliver by a coordinated engagement of at least one roller pair, in particular at least two of the roller pairs. This allows the sliver to be actively severed in order to dispose of an already damaged and/or weakened sliver end.

In particular, severing in the region between a center roller pair and an apron roller pair can be achieved, as described elsewhere. This can take place in particular in that the apron roller pair can be put into operation, in particular by driving the apron bottom roller, before the engagement of the remaining roller pairs of the drafting device. As a result, the apron roller pair can exert a pull on the sliver while the sliver is clamped by at least one other roller pair, in particular arranged opposite a pulling direction of the apron roller pair. This allows the sliver to be severed at a weak point.

According to a preferred aspect, the drafting device can be designed and configured to coordinate the severing of the sliver via a coordinated engagement of at least one roller pair, in particular at least two roller pairs, with a transfer of the air-jet spinneret to the cleaning position. This can make piecing in a cleaned air-jet spinneret possible.

The apron roller pair can be put into operation before the engagement of the remaining roller pairs of the drafting device in order to allow the sliver to be severed in the region between the center roller pair and the apron roller pair, as described elsewhere. In particular, with the engagement of the apron roller pair, the air-jet spinneret is moved to the cleaning position for removing the severed sliver section. Cleaning can take place as described elsewhere.

The method for severing the sliver between the output roller pair and the apron roller pair can also be used to partially automate the sliver feed.

In the preferred aspects and embodiments described herein, the sliver feed can be semi-automated. A so-called partial automation of the sliver feed is in particular a disposal of an “old” sliver end remaining in a drafting device after an interruption of spinning, and a feeding of a newly stretched sliver end for piecing to the air-jet spinneret. In particular, the air-jet spinneret is cleaned at the same time or in a manner coordinated in time, as described elsewhere. A semi-automated sliver feeding option is possible under the conditions described herein. However, not every possible sliver feed can be partially automated. An example of sliver feeding that cannot be (partially) automated is the placement (in the sense of a new insertion) of a new sliver. In this case, the machine operator can carry out manual sliver feeding by pressing a button. Partial automation can be implemented in terms of software and process, in particular as described elsewhere. The various roller pairs, as described elsewhere, can also be engaged, in particular in a coordinated manner, in particular individually or in any combination. The preferred aspects, features and functions of a semi-automated sliver feeding can also be formed separately from the other preferred aspects.

In particular, the process of a warm-up of an output roller drive, a stop and then a renewed acceleration from zero can support piecing. Alternatively or additionally, the other roller pairs can rotate at least partially. In the process, the rubber rollers (solid rubber rollers and/or rollers with rubber coating) can be kept warm. Meanwhile, the spinning station may be shut down due to quality defects, in particular of a thread and/or of a sliver or the like.

According to a preferred aspect, the drafting device can be designed and configured to specifically adjust 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 to be implemented as described elsewhere. Alternatively, a process parameter for driving at least two of the roller pairs can be specifically adjusted over a defined period of time.

In preferred embodiments, one process parameter in particular can be configured as an S profile. The ramp-ups of the drives in this case do not have to be linear over the entire ramp-up range. Instead, the drives that drive the roller pairs are in particular ramped up with a ramp-up profile in the form of an S-curve. The shape of the profile can be adjusted around a minimum and/or around a maximum. This in particular avoids extreme accelerations, which have a negative effect on the rollers or the drives, and which can also have a negative effect on the sliver in the event of contact between the rollers and the sliver. The S profile can be realized for the thread take-off, which takes a spun thread from a spinning station and in particular feeds it to a bobbin sleeve or empty sleeve for winding the thread, in particular via a traversing device of a textile machine producing take-up bobbins. Alternatively or additionally, the S profile can (also) be realized for the rollers of the drafting device. This can be used to bring the fibers into the air-jet spinneret at a slower rate (i.e., defined by mass per time) in order to achieve a slow increase in fiber mass. The term “slow” can refer here in particular to a coordinated increase in the fiber mass in order to make coordination with a thread take-off and, thereby, coordination with the spinning speed possible. This can prevent the thread from being formed unevenly and/or the air-jet spinneret from clogging.

In preferred embodiments, one process parameter can in particular be a decoupling. In particular, this means that the ramp-up profiles of the rest of the roller pairs of the drafting device no longer follow the ramp-up profile of the output roller pair. Due to the decoupling, the operation or the ramping up of the output roller pair, in particular the driven output bottom roller, can be coordinated in time separately from the remaining roller pairs of the drafting device 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 rotate while the remaining roller pairs of the drafting device are stationary. Alternatively or additionally, drives of the remaining roller pairs can be operated with a different parameter as described elsewhere. As a result, fluctuations in the operation of the output roller pair, in particular the output bottom roller, can be overcome. If the output roller pair, in particular the output bottom roller, does not ramp up evenly, the fibers cannot be passed on in the same quantity as they are passed on by the roller pairs of the remaining drafting device. This could cause the fibers to additionally stretch or to pile up. This can be compensated by individually controlling the remaining roller pairs. This makes it possible to form a uniformly shaped sliver. This also makes it possible to deliver fibers to the air-jet spinneret in a uniform manner. This also allows a continuously formed thread to be spun.

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

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

A piecing ramp can be the mathematical progression of a process parameter, for example in an X-Y diagram. This makes it possible to describe a ramping-up of more than just one point at which the process parameter changes. Such a point can be described as a support point. In particular, this is a point in the process parameter space. This makes it possible to realize a plurality of support points during the piecing ramp of at least one driven roller of the drafting device. An acceleration ramp with at least one driven roller of the drafting device can be provided with three support points, in particular in one embodiment.

The term “support point” means in particular the definition of a variable speed that is to be reached after a variable time. This change can, for example, prevent the tendency of the piecers to create a thin point after a binding zone. In particular, this results in a more flexible shaping of the fiber mass while piecing.

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 relevant rollers to be kept at a temperature for improved operation of a drafting device. This also means that warm-up times can be reduced or avoided altogether.

According to an independent aspect, a spinning station can have at least one spinneret, in particular an air-jet spinneret. The spinning station can have at least one thread end preparer. The spinning station can have at least one thread take-off. The spinneret and the thread end preparer can be arranged and designed to initiate piecing. The thread take-off can be arranged and designed to remove a thread from the spinneret after a spinning process. At least one roller pair of a drafting device, in particular the drafting device as described elsewhere, can be engaged in a coordinated manner via the drive of the roller pair. This allows clogging of the spinneret to be preventable since, for example, the supply of fibers can be controlled, in particular in a manner coordinated with the removal of a thread to be formed. Alternatively or additionally, a uniform thread can be formed.

According to a preferred aspect, the thread take-off is designed and configured in particular to be engaged along with the at least one roller pair in a coordinated manner. The at least one roller pair can have a ramp-up profile with a piecing ramp with at least two support points. This allows clogging of the spinneret to be preventable since, for example, the supply of fibers can be controlled, in particular in a manner coordinated with the removal of a thread to be formed. Alternatively or additionally, a uniform thread can be formed.

As already described elsewhere, the term “support point” refers in particular to the definition of a variable speed that can be reached after a variable time. This change can, in particular, prevent the tendency of the piecers to create a thin point after a binding zone. In particular, this results in a more flexible design of the fiber mass during piecing.

The piecing ramp can be an acceleration 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 is used in particular to transfer the 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 undergo a plurality of accelerations over the course of ramping up to an operating speed and can also reach a plurality of speeds in different times. The corresponding support points can be recorded in a speed-over-time diagram. The ramping up can start from a full stop. Alternatively or at other times, the ramping up can also start from a keeping-warm mode, i.e., from a kind of base speed.

In embodiments for the rollers of the drafting device, but also in combination with the aspects of the spinning station described herein, a piecer ramp can have an S profile, as described elsewhere, between at least two adjacent support points. In this case as well, this can reduce breakaway torques and/or avoid high accelerations, which can have a detrimental effect on the yarn quality or the sliver quality. This makes it possible to improve a piecing process, as described elsewhere.

In particular, two support points are adjacent in a diagram, such as a speed-over-time diagram, i.e., they follow one another directly in a diagram. “Direct” here means, in particular, that there is no support point in between.

According to a preferred aspect, the spinneret can be designed and configured to assume at least an operating position and a cleaning position different therefrom, as described elsewhere. Alternatively or additionally, the thread end preparer can be designed and configured to at least unravel a thread end by means of a compressed air supply, as described elsewhere. This can improve a piecing process, as already described elsewhere.

Piecing is based in particular on bringing together an, in particular prepared, thread end in a vortex chamber of the air-jet spinneret and newly arriving fibers of the sliver, as in particular also described elsewhere. The timing of the thread end return and the speeds and/or the running times of the drafting device are in particular important.

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 take-up bobbin) can be caught by a take-up bobbin 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 can be transferred to a thread end preparer. In the meantime, a thread take-off can be opened in order to insert the thread into the thread take-off. In particular, the thread take-off comprises a roller pair with an upper and a bottom 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-off (also known as a take-up) by the thread end catching device in the course of its movement to transfer the entrained thread end to the thread end preparer. A take-up can in particular be designed to take the thread. In particular, the taking can take place in that the thread, in the course of its movement, is inserted by a thread section by the thread end catching device into the take-up and is then clamped thereby, in particular after the thread end has been transferred from the thread end catching device to the thread end preparer. In particular, after being moved by the thread end catching device, the thread lies with a thread section on scissors and/or is arranged with a thread section or the thread end in front of a receiving opening of an unraveling tube of the thread end preparer. In particular, the thread take-off subsequently clamps the thread. In a subsequent step, in particular the scissors 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 thread end can be unraveled without a previous step of cutting the thread. The thread can be cut to a defined length during the cutting step. This allows any flaws in the spinning process to be removed.

Catching the thread end and guiding it in a direction opposite the thread running direction during the spinning process is referred to as a return or thread return. In particular, the return can take place in one step or a plurality of substeps, wherein a first, second, . . . , x-th return is then mentioned.

In one step, the (cut) thread end can be sucked into the unraveling tube and unraveled in the unraveling tube by introducing a flow of compressed air. In one step, a first return of the thread can take place in particular by rotating back the take-up that clamps the thread. The first return of the thread end to an outlet of a thread take-off channel of the air-jet spinneret can be supported by introducing an air flow accompanying the thread end or the thread into a thread guide channel guiding the unraveled thread end, wherein the thread guide channel can be part of the thread end preparer and in particular can comprise or form the unraveling tube and furthermore preferably extends to the outlet of the thread take-off channel of the air-jet spinneret. This allows the thread end to be guided through the thread guide channel to the outlet of the thread take-off channel of the air-jet spinneret in a first return step.

In one step, in particular after the first return, a thread loop can be placed in a pneumatic thread storage, which is arranged in the thread running direction between the air-jet spinneret and the take-up bobbin or the take-up bobbin holder for rotatably holding the take-up bobbin, in particular between the take-up and the take-up bobbin or the take-up bobbin holder. The thread loop can serve as compensation since the ramp-up times and accelerations of at least one of a drive shaft for contact-driving the take-up bobbin, a take-up bobbin, a drafting device, and/or a take-up can be different. 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 sliver clamped between the output bottom and top rollers and in order to keep warm the drive of the output roller, in particular the output bottom roller, and/or the rubber lining of the output rollers.

In one step, in particular a second return of the thread follows. In particular, this takes place right into a vortex chamber (also referred to as a spinning chamber) so that the unraveled thread end can be caught by the air flow. For this purpose, the air flow can be introduced into the vortex chamber of the air-jet spinneret via the spinnerets ending in the vortex chamber, which air flow generates a suction flow in the thread take-off channel of the air-jet spinneret, whereby the thread end can be sucked into the thread take-off channel and transported along to the vortex chamber of the air-jet 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-forming element) of the spinneret in order to be caught by the vortex air flow. In particular, the air-jet spinneret is usually constructed with a two-part housing, with one housing part bearing the sliver inlet and the other housing part bearing the yarn-forming element with the thread take-off channel. The two housing parts are designed to move relative to one another and, in a coupled state, form the vortex chamber formed between the sliver inlet and the yarn-forming element.

In one step, the rotating output roller, in particular the output bottom roller, is stopped. The drafting device can be started depending on input parameters, which is referred to as ramping up.

The input parameters for the ramp-up, which in particular define a ramp-up profile, can in particular be one of a lead time, a piecing speed, a speed profile, a speed for a first stage, a duration of operating a first stage, and/or a total ramp-up time of the drafting device or of the at least three roller pairs arranged therein, comprising an input roller pair, a center roller pair, and an output roller pair. Furthermore, an apron roller pair can be provided, which is arranged between the center roller pair and the output roller pair. The apron roller pair can preferably follow the ramp-up profile of the output roller pair, in particular while ramping up.

A speed profile that makes up the ramp-up profile can in particular have at least one of four sub-parameters. This sub-parameter can be selected from a speed for a first stage, a duration of operating a first stage, a total ramp-up time of the drafting device, and a thread take-up acceleration, which in particular determines the total ramp-up time of the thread take-up.

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

In one step, the thread take-off in particular ramps up at the end of its dwell time in accordance with a specified and/or entered acceleration. Running is understood herein to mean the driven operation of the thread take-off. In the meantime, the drafting device can also ramp up. The thread is therefore pulled out of the spinning chamber, in particular by means of the driven thread take-off, wherein the piecing process is completed, in particular after the ramp-up times have elapsed.

Additionally or alternatively, a spinneret, in particular an air-jet spinneret, can be designed and configured to assume at least one cleaning position, in particular as described elsewhere. This allows fragments of a sliver to be removed from the drafting device. As a result, the piecing process can be improved, and resources can be saved.

Before or at the latest with the start of the remaining roller pairs, the air-jet spinneret can be moved to a cleaning position in order to be able to remove the “old” sliver. Subsequently, the roller pairs can be stopped, and the air-jet spinneret can resume the operating position in order to continue the piecing process, as described elsewhere, by starting the drafting device in a defined manner. In particular, the described stopping of the output roller pair can be omitted since the drafting device can already be stopped.

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

The aspects and/or embodiments of the spinning station described herein, in combination with the aspects and/or embodiments of the drafting device described elsewhere, can optimize an operation of a textile machine by preparing the sliver for being fed into a spinneret, as described elsewhere. Alternatively or additionally, a return of a thread end can be improved and coordinated, in particular with feeding a 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 the sliver from being pulled apart or stretched too far. A damaged sliver can also be replaced, which can optimize the feeding of fibers into a spinneret of a spinning station. In particular, this allows the thread to be produced in a spinneret to be formed evenly. The combination, as described, also makes it possible to coordinate the timing of the take-off of a spun thread with the incoming fibers. This allows the thread to be shaped evenly, which can have a positive effect on textiles into which the thread can be incorporated.

The spinning station can be formed on its own, i.e., without being combined with the drafting device described herein. A thread take-off of a thread can be adapted to an activity of the spinneret of a corresponding spinning station.

According to an independent aspect, a method can be formed. The method can have at least one step of severing a sliver by coordinated engagement of at least one roller pair, in particular at least two roller pairs, of a drafting device, in particular a drafting device as described elsewhere.

The method can alternatively or additionally comprise at least the step of piecing by coordinated engagement of at least two roller pairs of the drafting device, in particular the drafting device as described elsewhere.

The method can alternatively or additionally comprise at least the step of piecing by coordinated engagement of at least one thread take-off of a spinning station. In particular, the spinning station can be a spinning station as described elsewhere. In particular, the step of piecing can be designed to feed a thread end back into a spinneret.

The method can alternatively or additionally comprise at least the step of spinning a thread. This step can be carried out in particular after piecing has been completed. In particular, the step of spinning can comprise a coordinated engagement of the thread take-off and of at least one roller pair of the drafting device, in particular a drafting device as described elsewhere.

The method can be described by the features, the effects, and the advantages of the textile machine, by the features, the effects, and the advantages of the drafting device, as well as by the features, the effects, and the advantages of the control apparatus. The textile machine, the drafting device as well as the method can be described by the features, effects, and advantages of the control apparatus.

According to an independent aspect, a control apparatus can be designed and configured to carry out a method as described elsewhere. The control apparatus can be described by the features, the effects, and the advantages of the textile machine, by the features, the effects, and the advantages of the drafting device and by the features, the effects, and the advantages as presented with regard to the methods. The textile machine, the drafting device as well as the method can be described by the features, the effects, and the advantages as presented with regard to the other categories. Accordingly, the control apparatus can be described by the features, the effects, and the advantages of the spinning station as described elsewhere. The features, the effects, and the advantages of the control apparatus can describe the spinning station as described elsewhere.

According to an independent aspect, a textile machine can have at least one drafting device as described elsewhere. Alternatively or additionally, the textile machine can have a spinning station as described elsewhere. Alternatively or additionally, it can have a control apparatus as described above. Alternatively or additionally, the textile machine can be designed and configured to perform a method as described elsewhere.

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

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

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

In summary and in other words, this means that in particular in cases in which a partially automated sliver feeding can be carried out, for example shutdowns of the spinning station due to quality defects and thread breaks, as well as when a spinning station has not produced for a longer period of time, the running times and parameters can be variably set by software. In particular, the sliver feeding is carried out before the spinning station is started after a shutdown (quality defects, thread breaks) or a long downtime of the spinning station. In particular, the rollers or the roller pairs of the drafting device are operated using an adjustable speed and an adjustable running time according to their draft (variable since this depends on the yarn count being produced). In particular, a new part of the sliver is stretched and delivered in the direction of the spinneret, and the old sliver with any irregularities is removed. During this time in particular, the spinning station assumes a cleaning position. Excess fibers that arise during the sliver feed can be removed more easily. This can eliminate/prevent fiber clogging, in particular in a spinning station. The cleaning position is in particular variable and includes in particular at least two different variants.

In a first variant, the spinning pressure can be switched off and, in particular, the spinneret does not open. The fibers can enter into a suction unit, in particular either an upper and/or a lower suction unit.

In a second variant, the spinning pressure can be switched on and the spinneret can be opened. The fibers are in particular sucked through the fiber inlet and sucked out below the spinneret.

Alternatively or additionally, the sliver feed can be partially automated by switching on an apron drive, for example, during the warming up of the output roller pair, in particular the output bottom roller. This allows the sliver to be severed in a so-called main draft zone. For this purpose, the sliver is in particular not fed before the start of the piecing process, but in particular after a warm-up. In particular, the sliver can be fed 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. The spinneret is opened briefly, in particular at the start of the thread return. The spinning pressure is already on, in particular during this part of the piecing process. This in particular results in the second variant of the cleaning position, in particular at a later point in time.

The sliver feeding results in particular depending on the setting of a drafting device, i.e., depending on the set distances between the roller pairs, wherein the running time can be variably adjusted. The distance between the roller pairs can, in particular, be variably adjustable and support the stretching of the sliver.

Alternatively or additionally, the control apparatus or the machine-readable code executed thereon can be used to control in a coordinated manner an activity of a spinning station, in particular a spinneret and/or thread end preparer, in particular a compressed air supply for unraveling a thread end and/or an unraveling tube for unraveling a thread, in particular together with at least one drivable roller, in particular a bottom roller of a drafting system. For at least one drivable roller, in particular at least one bottom roller, a plurality of support points can be formed in a ramp-up, as described elsewhere. The drivable roller can be an output roller, in particular an output bottom roller.

In the following, exemplary embodiments of the invention are described in more detail with reference to figures, showing schematically and by way of example:

FIG. 1 a schematic representation of a piecing method;

FIG. 2A a view of a sliver position in one embodiment of a drafting device after a shutdown;

FIG. 2B a view of a start of the warm-up of an apron bottom roller and/or output bottom roller in an embodiment of a drafting device, wherein the sliver is severed;

FIG. 2C a view of a sliver position after the end of the warm-up of the apron bottom roller/output bottom roller in one embodiment of a drafting device;

FIG. 3A a view of a first cleaning position in one embodiment of a drafting device;

FIG. 3B a view of a second cleaning position in one embodiment of a drafting device;

FIG. 4 a schematic representation of a piecing ramp of an output bottom roller and a thread take-off;

FIG. 5 a schematic representation of a piecing ramp with a support point;

FIG. 6 a schematic representation of a piecing ramp with an S profile;

FIG. 7 a schematic representation of a piecing ramp with a support point; and

FIG. 8 a schematic representation of a piecing ramp with three support points.

The same reference signs are used for elements and structures having the same effect and/or of the same type.

FIG. 1 shows a schematic representation of a piecing method 100 on a textile machine, in particular an air-jet spinning machine. A catching of a thread end of a thread (also referred to as upper thread) deposited on a take-up bobbin can be configured in a step 1. In this step 1, the thread end can be caught by a movable thread end catching device such as a suction nozzle. Meanwhile, a thread take-off formed by a roller pair can be opened in order to allow the thread to be inserted into the thread take-off.

In a step 2 of placing a thread section of the thread, the thread can be inserted into the thread take-up, a so-called take-up, via deflection contours in the course of moving the thread end catching device. In particular, the take-up can be designed to take 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 region of scissors and/or in front of an opening of an unraveling tube of a thread end preparer. The thread take-off clamps the thread, in particular after the thread end has been arranged as described above.

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

In a step 4 of unraveling the thread end, the thread end can be unraveled by introducing a flow of compressed air into an unraveling tube.

In a step 5 of a first return of the thread to an outlet of a thread take-up channel of an air-jet spinneret, a first return of the thread can be supported by rotating back the take-up clamping the thread and by introducing an air flow accompanying the thread end or the thread into a thread guide channel guiding the unraveled thread end, wherein the thread guide channel can be a component of the thread end preparer and in particular can comprise or form the unraveling tube and furthermore preferably extends up to the outlet of the thread take-up channel of the air-jet spinneret. The spinning pressure can be used for air-accompanied transport within the thread take-off channel; alternatively or additionally, the thread can be blown further within the thread guide channel by a compressed air supply.

In a step 6 of laying a thread loop, in particular after the step 5 of the first return, the step 6 of laying the thread loop can take place in a pneumatic thread storage, which is arranged in the thread running direction between the air-jet spinneret and the take-up bobbin or the take-up bobbin holder for rotatably holding the take-up bobbin, in particular between the take-up and the take-up bobbin or the take-up bobbin holder. The thread storage can serve as compensation since the ramp-up times and accelerations of at least one of a drive shaft, a take-up bobbin, a drafting device 101, and/or a take-up can be different.

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

In the case of a partially automated sliver feed, the above step 7 can in particular be adapted. In other words, in particular after step 6 or with step 7, the remaining roller pairs of the drafting device 101 (input roller pair, center roller pair(s) and, if present, apron roller pair) are engaged in a defined manner in order to start a defined drawing-in and stretching of the sliver. Before or at the latest with the start of the remaining roller pairs, the air-jet spinneret can be moved to a cleaning position (see the two variants described elsewhere) in order to be able to remove the “old” sliver. Subsequently, the roller pairs can be stopped, and the air-jet spinneret in particular resumes the operating position in order to continue the piecing process as described elsewhere, in particular by starting the drafting device 101 in a defined manner (see step 9). In this case, 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.

This can be supplemented by putting the apron roller pair into operation, in particular by driving the apron bottom roller, before the engagement of the remaining roller pairs of the drafting device 101 in order to achieve a severing of the sliver 31 in the region between the center roller pair and the apron roller pair. With the engagement of the apron roller pair, the air-jet spinneret in particular is moved to the cleaning position for removing the severed sliver section.

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 particular, the operation of a roller can have at least two support points during a ramp-up in a piecing ramp or in an acceleration ramp of a ramp-up profile of the roller. This is described in detail elsewhere.

In a step 8 of a second return, a second return of the thread follows in particular. In particular, this takes place right into a vortex chamber (also referred to as a spinning chamber) so that the thread end can be caught by the air flow.

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

The input parameters for the ramp-up, which define the ramp-up profile, can in particular be one of a lead time, a piecing speed, a speed profile, a speed for a first stage, a duration of operating a first stage, and/or a total ramp-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 in the ramp-up.

A speed profile that makes up the ramp-up profile can in particular have at least one of four sub-parameters. These can be selected from a speed for a first stage, a duration of operating a first stage, a total ramp-up time of the drafting device 101, and a thread take-up acceleration, which in particular determines the total ramp-up time of the thread take-up.

The thread end can be held in the spinning chamber during a dwell time of the thread take-off, which makes it possible to adjust the preparation of the drafting device 101 in a defined manner.

In a step 10 of dwelling for a dwell time, the thread take-off in particular ramps up at the end of its dwell time in accordance with a specified and/or entered acceleration.

In a step 11 of running in a running time of the thread take-off, the drafting device 101 also ramps up in particular during this time. Running is understood herein to mean the driven operation of the thread take-off. The thread is pulled out of the spinning chamber by means of the driven thread take-off after connection to the sliver 31 for continuous spinning of the thread, wherein the piecing process is completed in particular after the ramp-up times have elapsed.

FIG. 2A shows a view of a sliver position in one embodiment of a drafting device 101 after a shutdown of the illustrated bottom rollers 20, 22, 24, 26 of roller pairs, which are each composed of one of the bottom rollers 20, 22, 24, 26 and respectively assigned top roller in order to transport the intermediate sliver 31 in a closed state while the roller pairs are rotating, driven by the illustrated bottom rollers 20, 22, 24, 26. In particular, an input bottom roller 20 of an input roller pair, a center bottom roller 22 of a center roller pair, an apron bottom roller 24 of an apron roller pair, and an output bottom roller 26 of an output roller pair are shown in a row, which are part of the drafting device 101. The drafting device 101 is attached to a carrier 12 via a locking device 16. In particular, the input bottom roller 20 is rotationally driven by an input bottom roller drive 30. In particular, the center bottom roller 22 is rotationally driven by a center bottom roller drive 32. In particular, the apron bottom roller 24 is rotationally driven by an apron bottom roller drive 34. In particular, the output bottom roller 26 is rotationally driven by an output bottom roller drive 36. In particular, an apron 28 runs around the apron bottom roller 26 and can also be guided around an apron bridge 29 in order to build up tension in the aprons 28. The bottom rollers 20, 22, 24, 26 can be adjusted in their relative position to one another via an adjusting 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 in the absence of their own drive.

FIG. 2B shows a view of a start of the warm-up of an apron bottom roller 24 and/or output bottom roller 26 in one embodiment of the drafting device 101, wherein the sliver 31 is severed in a severing region 25.

FIG. 2C shows a view of a sliver position after the end of the warm-up of the apron bottom roller 24 and/or output bottom roller 26 in one embodiment of the drafting device 101. The severing region 25 can be located in a region of a compressor that is positioned upstream of the apron bottom roller 24.

During a step 7 as described with reference to FIG. 1, the spinning station with the cleaning nozzle can move to the cleaning position. Excess fibers that arise during a warm-up can be removed more easily without causing fiber clogging, in particular in a spinneret 40. The cleaning position is in particular variable and can have two different variants as shown in FIGS. 3A and 3B and described below.

FIG. 3A shows a view of a first cleaning position in one embodiment of the drafting device 101. A sliver 31 is guided between an output top roller 27 and an output bottom roller 26 and transported by the rotation of the rollers. A spinning pressure inside the spinneret 40 can be switched off, and the spinneret 40, which is formed from two housing parts, can be closed, i.e., cannot open. As a result, the fibers of the sliver 31 or its fragments 14 can enter either the upper suction unit 13 or the lower suction unit 15, which are correspondingly 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 therefore sucked off.

FIG. 3B shows a view of a second cleaning position in one embodiment of the drafting device 101. The spinning pressure can be switched on and the spinneret 40 can be open or 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. In particular, the fibers of the sliver 31 or its fragments 14 are sucked through the fiber inlet 21 and via a fiber suction unit 23 communicating with the spinning chamber in the open position of the spinneret 40, i.e., in a spaced-apart position of the spinning cone 42 from the fiber inlet 21 (not shown). After the step 7 of stopping the output bottom roller drive 36 and the apron bottom roller drive 34 has elapsed, the spinning station in particular resumes its normal spinning position (spinning pressure on, spinneret 40 closed as shown in FIG. 3A). The next process steps then take place as described elsewhere. The second return 8 of the thread follows, and the drafting device 101 or its bottom rollers 20, 22, 24, 26 is/are accelerated using the parameters in step 9 described elsewhere. In particular, the parameters in step 9 are adapted such that they can be used to transport the fibers to the spinneret 40. In particular, significantly longer times are entered for this purpose. The piecing ramp for this case is schematically illustrated in FIG. 4 (not to scale).

FIG. 4 shows a schematic representation of a piecing ramp 420 of a driven output bottom roller 26 in comparison to a piecing ramp 410 of a driven roller of a thread take-off. The time 415 in milliseconds (ms) is plotted on the X-axis. The speed of the output bottom roller 26 or the driven roller of the thread take-off is plotted on the Y-axis, approximately in units of revolutions per minute. A sliver feed 400 is realized in particular within a time range (negative time range). In particular, the output bottom roller 26 is already activated, which is why a piecing ramp 420 already forms at this time. The thread take-off is still stopped at a zero time (selected as the starting point of the speed increase of the driven output bottom roller 26 in a piecer ramp 420). This makes the following things possible:

In particular, the first start-up of the apron bottom roller drive 34 and of the output bottom roller drive 36 without the sliver 31 takes place in this first time range. In particular, this prevents the breakaway torque from having an effect in this zone. Furthermore in particular, the piecing takes place when the drafting device 101 has already started up, which can reduce stress in the sliver 31.

FIG. 5 shows a schematic representation of a piecing ramp 530 with a support point 550. The speeds 505 are plotted against the time 515. This results in piecing ramps 510 for a thread take-off roller drive or for the driven thread 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 in front of a first support point 550. The thread take-off can remain in a dwell time 540. The dwell time 540 of the thread take-off runs in particular in such a way that the thread end is held in the spinning chamber and makes it possible to adjust the preparation of the drafting device 101. This is shown in step 10 in FIG. 1 and described with reference thereto. In particular, the thread take-off ramps up at the end of its dwell time 540 in accordance with the entered acceleration while the drafting device 101 in particular also ramps up. In particular, the thread is pulled out of the spinning chamber 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 thread take-off.

FIG. 6 shows a schematic representation of a piecing ramp 630 for an output bottom roller drive or for the driven output bottom roller 26 with an S profile 610, 620 as an example of a process parameter. The speed 605 is plotted over the time 615. In particular, the ramp-ups of the drives (of the bottom rollers 20, 22, 24, 26) take place not exclusively linearly, but with an S-curve, which can be adjustable. This means that extreme accelerations can be avoided. The S profile 610, 620 can be realized both for the thread take-off and for the drafting device 101 or its driven bottom rollers 20, 22, 24, 26.

FIG. 7 shows acceleration ramps (speed 705 over time 715) of the drafting device 101, wherein only one support point 725 can be formed during the ramp-up in 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 explanations of FIG. 5 also apply here.

FIG. 8 shows acceleration ramps (speed 705 over time 715) of the drafting device 101, wherein three support points 725, 735, 745 can be formed by way of example during the ramp-up of an acceleration ramp 720 of an output bottom roller 26. The corresponding explanations of FIGS. 5 and 7 also apply here. The three support points 725, 735, 745 mean in particular a definition of a variable speed 705, which can be reached after a variable time 715. This change can, for example, prevent the tendency of the piecers to create a thin point after the binding zone. In particular, this results in a more flexible design of the fiber mass during piecing.

“Can” in particular refers to optional features of the invention. Accordingly, there are also developments and/or exemplary embodiments of the invention which additionally or alternatively have the respective feature or the respective features.

From the combinations of features disclosed in the present case, isolated features can also be taken as needed and used by resolving a structural and/or functional relationship possibly existing between the features in combination with other features for delimiting the subject matter of the claim.

LIST OF REFERENCE SIGNS

- 1 Catching a thread end of a thread
- 2 Placement of a thread section of the thread in the take-up
- 3 Cutting the thread with scissors
- 4 Unraveling the thread end
- 5 First return of the thread
- 6 Laying a thread loop
- 7 Combing out and keeping warm
- 8 Second return
- 9 Stopping the output bottom roller
- 10 Dwell time
- 11 Running time of the thread take-off
- 12 Carrier
- 13 Upper suction unit
- 14 Fragments
- 15 Lower suction unit
- 16 Locking device
- 18 Adjusting device
- 20 Input bottom roller
- 21 Fiber inlet
- 22 Center bottom roller
- 23 Fiber suction unit
- 24 Apron bottom roller
- 25 Severing region
- 26 Output bottom roller
- 27 Output top roller
- 28 Apron
- 29 Apron bridge
- 30 Input bottom roller drive
- 31 Sliver
- 32 Center bottom roller drive
- 34 Apron bottom roller drive
- 36 Output bottom roller drive
- 40 Spinneret
- 42 Spinning cone
- 100 Piecing method
- 101 Drafting device
- 400 Sliver feed
- 410 Piecer ramp for a thread take-off drive
- 405 Speed
- 415 Time
- 420 Piecer ramp for an output bottom roller drive
- 505 Speed
- 510 Piecer ramps for a thread take-off drive
- 515 Time
- 520 Piecer ramp
- 530 Piecer ramp with one support point
- 540 Dwell time
- 550 Single support point
- 551 Speed level
- 560 Total ramp-up time of the drafting device
- 570 Total ramp-up time of the thread take-off
- 605 Speed
- 610, 620 S profile
- 615 Time
- 630 Piecer ramp of an output bottom roller with S profile
- 705 Speed
- 710 Acceleration ramp of a thread take-off roller drive
- 715 Time
- 720 Acceleration ramp of an output bottom roller
- 730 Acceleration ramp of an input bottom roller
- 725, 735, 745 Support points