JP7553257B2 - Method for producing a splice joint in a working unit of a textile machine and working unit of a textile machine - Patents.com - Google Patents

Description

The present invention relates to a method for forming a splice joint between an upper thread and a lower thread in an operating unit of a textile machine, a corresponding operating unit of the textile machine, and a winding machine having at least one corresponding operating unit.

Methods for joining two yarn ends, in particular by piecing, are already known from the prior art in various configurations. Thus, for example, in a winding machine, the yarn is rewound from several relatively small yarn supply bobbins onto a large-capacity package, which requires multiple joining of the already wound yarn, i.e. the upper thread, with the yarn coming from a new yarn supply bobbin, i.e. the lower thread. However, this method according to the prior art does not in all cases result in a reliable and error-free joining of the two yarn ends, which often leads to an immediate break of the joined yarn and to the yarn ends having to be found and joined again. Furthermore, poor-quality yarn joints result, which lead not to an immediate break of the yarn during winding, but to a break only during a subsequent processing process, for example when weaving a fabric or sewing with the yarn.

From DE 10 2009 024 037 A1, a method for preventing thread breakage in a working unit of a winding machine for rewinding a thread from a winding bobbin onto a winding package is already known. The winding machine has a thread coupling device, preferably a splicing device, arranged outside the normal thread path for coupling the upper thread of the winding package with the lower thread of the winding bobbin, and a device for holding the lower thread arranged in the normal thread path and a swivellable suction nozzle supplied with negative pressure for capturing the upper thread and transporting the thread end of the upper thread to the underside of the thread coupling device. The device for holding the lower thread holds the lower thread above the thread coupling device in the event of a thread breakage, and the suction nozzle and the insertion lever introduce the upper and lower threads into the thread coupling device when the suction nozzle is swivelled downwards. However, such a method usually results in an erroneous coupling of both thread ends, which correspondingly leads to immediate or subsequent breakage of the thread at the coupling point.

The object of the present invention is therefore to provide a method for forming a splice joint between an upper thread and a lower thread in an operating unit of a textile machine, which ensures a consistently high splice quality and a reliable reproducibility of the splice joint, in particular preventing tension breaks during the splice joint, as well as a corresponding operating unit of the textile machine.

This object is achieved according to the invention by a method according to claim 1, by a working unit of a textile machine according to claim 14 and by a winding machine according to claim 15. Advantageous developments of the invention are described in the dependent claims.

The method according to the invention for forming a spliced joint of an upper thread and a lower thread in a working unit of a textile machine comprises as method steps firstly a step of feeding at least the upper thread and possibly the lower thread to a splicing unit and a step of measuring the thread tension of at least the upper thread to be joined by a thread tension sensor before the splicing. The measured thread tension is then compared with a preset limit value and, if the limit value is exceeded, the upper thread tension is reduced, in particular at least one measure for reducing the upper thread tension is implemented. Finally, if the measured thread tension is below the preset limit value, the joining of the thread ends of the lower thread and the upper thread in the splicing unit is performed.

The working unit according to the invention of a textile machine, in particular a winding machine, has a splicing unit for joining the lower thread and the upper thread, and a lower thread supply and an upper thread supply to the splicing unit. A thread tension sensor is arranged in the upper thread supply so that the thread tension of the upper thread to be joined can be measured before the splicing or for measuring it. Finally, the working unit includes a control unit for comparing the measured thread tension with a preset limit value. If the limit value is exceeded, the control unit reduces the upper thread tension or initiates at least one measure for reducing the upper thread tension.

The winding machine according to the invention has at least one working unit according to the invention, and preferably has several working units according to the invention. Particularly preferably, all working units according to the invention are formed identically to one another.

The inventors of the present invention have realized that poor splicing quality and an unreliable joining of both yarn ends are caused by the thread tensions of the upper and lower threads not always being the same when introduced into the splicing unit. In particular, the tension of the upper thread, which is placed in the splicing unit, in particular preferably in the splicing prism of the splicing unit by means of a suction nozzle, varies very strongly and thus leads to an unsatisfactory splicing result. The detailed reasons for a too high upper thread tension are diverse, for example the thread may be twisted in the suction channel with another thread, in particular with a loose thread piece, or the thread may become stuck on the traverse package. This different thread tension then leads to a variable quality at the splice joint, which ultimately leads to a tension break during the splicing process. The upper thread under tension is often returned to the traverse package in such a way that the end of the upper thread reaches the side of the traverse package, resulting in an upper thread error, since the thread end cannot be found at the side, in particular by automatic thread search by means of a suction nozzle.

The present invention overcomes this drawback in a simple manner: by measuring the yarn tension of the upper thread, it is possible to essentially prevent joining under too high an upper thread tension, so that a weakened splice joint with reduced quality does not even form and correspondingly no problems arise later, in particular during the winding process and/or subsequent processing of the yarn.

The method according to the invention is particularly intended for forming a connection between two thread ends by means of a thread splice or for overcoming a thread interruption or thread break. For this purpose, the working unit according to the invention has a splicing unit. The splicing unit can basically be of any desired design and can have any other function.

The two thread ends to be joined together are the ends of the upper thread and the lower thread. The lower thread is the thread or thread section that runs upstream of the working unit in the thread running direction up to the splicing unit. Correspondingly, the upper thread is the thread or thread section that runs downstream of the splicing unit in the thread running direction of the working unit, in particular up to or onto the traverse package. In the case of a joined thread formed as a single, single thread by the joining of the lower thread and the upper thread, the entire thread can possibly be divided into a lower thread section upstream of the splicing unit in the thread running direction and an upper thread section downstream of the splicing unit in the thread running direction, where the lower thread becomes the upper thread in the splicing unit when the thread is moving in the thread running direction.

A textile machine can basically be any machine for producing and/or processing at least one, preferably several threads at the same time. Preferably, at least a part of the textile machine, particularly preferably the entire textile machine, is provided for rewinding the thread, in particular from one or several yarn supply bobbins or spinning cops into a single large-volume traverse package. Particularly preferably, each working unit has a winding device, and very particularly preferably, each working unit of the textile machine, in particular of a winding machine, is a winding device.

The winding device is essentially a device provided for producing a yarn package from individual yarns. The winding device may be a separate component, in particular a separate machine. Preferably, the winding device is part of a textile machine or spinning machine, in particular a rotor spinning machine. It is also preferably one of a number of working units, in particular one and the same number of working units, of a textile machine which produces a package, in particular a twill package. Particularly preferably, the winding device is a working unit of an automatic winding machine, in particular an autocorner. Such a winding device or such a working unit which each has a winding device preferably further comprises a lower thread sensor, a thread tensioner, a thread clearer with a thread cutting device, a thread tension sensor, a thread catcher nozzle and/or a paraffin feeder.

In textile machines, the splicing unit is preferably arranged outside the normal thread path, so that uninterrupted threads do not come into contact with the splicing unit and/or the thread ends to be joined must be fed to the splicing unit in order to enable joining. The feeding of at least the upper thread, and preferably also the lower thread, can first be carried out in any manner. The feeding is preferably assisted by an air flow or by a vacuum, particularly preferably by an air flow and in particular by a vacuum. For this purpose, the feeding is carried out by the corresponding thread feed, i.e. by an upper thread feed for the upper thread and/or by a lower thread feed for the lower thread. The lower thread feed or the upper thread feed can be designed as a component or a component group and can guide the lower thread or the upper thread only in sections or completely. Alternatively, however, the thread feed can also be completely or at least in sections, simply a functional unit, i.e. a section of a working unit through which the respective thread section runs. The threads may therefore also run sectionwise, through free space and/or without being surrounded by other components of the textile machine.

According to the invention, a measurement of the thread tension of at least the upper thread to be joined is performed at least before the joining, preferably at least once during the joining, particularly preferably periodically and particularly preferably continuously. In addition, a measurement of the thread tension of the lower thread is also possible, which measurement is particularly preferably performed corresponding to the measurement of the thread tension of the upper thread. The measurement of the upper thread tension is performed by a thread tension sensor. The thread tension sensor is arranged at the upper thread feed or in the area of the upper thread feed and/or in the splicing unit such that the thread tension of the upper thread inserted or to be inserted can be measured, while preferably the joined thread does not come into contact with the thread tension sensor. The thread tension sensor is likewise preferably arranged above or downstream of the splicing unit, in particular along the thread path of the thread to be wound, so that the upper thread can be detected by the thread tension sensor. The thread tension sensor can basically be any sensor that can detect the tensile force of the thread directly or indirectly along the thread path.

Following at least one measurement of the thread tension, according to the invention, the measured thread tension is compared with a preset limit value. The limit value may be different and/or adapted for different threads, in particular for different materials, thread strengths and/or types of thread production. The comparison is preferably carried out in a control unit, which reduces the upper thread tension or initiates measures for this purpose if the limit value is exceeded. The reduction of the upper thread tension can be carried out in any manner, even resulting from the release or separation of the upper thread end fed to the splicing unit and a new feed of a new upper thread end. The thread tension is then particularly preferably measured again.

The joining of the thread ends of the lower thread and the upper thread in the splicing unit takes place according to the invention only if the measured thread tension is below a limit value. This means that the measured thread tension must be below the preset limit value at least at the beginning of the splicing process or before the start of the splicing process, and preferably the measured thread tension of the upper thread must continue to be below the preset limit value even during the splicing process.

In an advantageous embodiment of the method according to the invention for producing a spliced joint, the upper thread is fed to the splicing unit by a suction nozzle supplied with negative pressure. The suction nozzle is preferably pivotable between a suction position for sucking in the free upper thread end and a feed position for feeding the free upper thread end to the splicing unit. This allows a reliable feeding of the thread end to the splicing unit and also makes it particularly easy to control or adjust the thread tension of the upper thread fed at least partially by negative pressure. The suction position is preferably located above the feed position in the thread running direction. Furthermore, the suction nozzle is preferably pivoted exclusively about a single axis for feeding the upper thread end to the splicing unit.

A particularly advantageous embodiment of the method according to the invention for producing a spliced joint provides that the suction nozzle for supplying the upper thread to the splicing unit captures the free upper thread end at a suction position in the area of the traverse package for winding the thread. The suction nozzle preferably draws the upper thread from the traverse package rotating in the unwinding direction, thereby enabling a further reduction in the thread tension of the upper thread in a particularly simple manner. The rotation of the traverse package in the unwinding direction can be achieved either on the basis of the negative pressure force of the suction nozzle acting on the upper thread or by active driving of the traverse package. Furthermore, the suction nozzle preferably extends over the entire width of the traverse package and/or can additionally be pivoted along the width of the traverse package, so that the upper thread can be reliably captured and sucked in from any position on the traverse package in a simple manner.

According to a preferred variant of the method according to the invention for producing a spliced joint, the free upper thread end is inserted directly into the splicing unit by means of a swivellable suction nozzle when the upper thread is fed to the splicing unit. It is also preferred that the splicing unit has a splicing prism into which the upper thread end is inserted by means of the suction nozzle. This allows a particularly simple and rapid feeding of the thread to be achieved, while at the same time allowing the upper thread fragments which arise in a particularly simple manner when the thread tension is reduced due to the separation or cutting of the free upper thread end to be sucked in and removed.

It is particularly preferred that the measurement of the thread tension of the upper thread is carried out during the process of inserting the upper thread into the splicing unit, in particular by means of a pivotable suction nozzle, and/or in the feed position of the suction nozzle. This allows the detection of excessively high thread tension to be carried out particularly quickly and simultaneously immediately after the detection and feed of the upper thread end and correspondingly immediately before the splicing process, so that erroneous splicing joints based on this are prevented in all cases.

A further particularly preferred embodiment of the method according to the invention for producing a spliced joint is that the upper thread is placed or introduced onto the measuring ring of the thread tension sensor, in particular by means of a pivotable suction nozzle and/or at the feed position of the suction nozzle, in order to measure the thread tension. This allows the measurement of the thread tension to be carried out in a forced and simple manner. The upper thread is preferably introduced into the measuring ring by means of a pivotable suction nozzle immediately before or during insertion into the splicing prism of the splicing unit. The measuring ring is preferably arranged directly in the thread path between the splicing unit and the traverse package. At the same time, however, the measuring ring is particularly preferably arranged on the working unit so as to be outside the thread path of the unsplit thread, which allows for unhindered winding onto the traverse package.

Furthermore, a particularly preferred embodiment of the method according to the invention for forming a splice joint provides that during the joining of the thread ends of the lower and upper threads in the splicing unit, a measurement of the thread tension of at least the upper thread to be joined is performed, preferably also during the joining if a limit value is exceeded, so that in a simple manner, an erroneous joining of the thread ends due to too high a thread tension occurring during the splicing process can be particularly effectively prevented. The measurement during joining is preferably performed continuously, although measurements are basically also possible only at preset times during the splicing process and/or periodic measurements. Particularly preferably, a corresponding monitoring of the thread tension of the lower thread is performed at the same time.

Basically, the reduction of the yarn tension can be carried out in any manner and by any one or several measures. In particular several measures can be used in succession or simultaneously. In particular measures of changing the yarn length, changing the position of the splicing unit or the spacing of the splicing unit relative to the traverse package and/or correspondingly adapting the speed of the method or individual method steps to be performed are possible.

In one possible measure, the tension of the upper thread is reduced, in particular by interrupting the supply of the upper thread by the suction nozzle and/or the combination of the lower thread with the upper thread, preferably by repeating it later. After the combination is interrupted, preferably the at least partially combined part of the lower thread and/or the upper thread is discarded, particularly preferably first cut off. Very particularly preferably, the upper thread is cut off, in particular between the suction nozzle and the traverse package, and the free end of the upper thread formed in the process is sucked in again. The cutting is preferably carried out by a cutting or thread separating unit which is arranged downstream of the splicing unit in the yarn running direction and/or between the splicing unit and the traverse package. Particularly preferably, the cutting or thread separating unit is arranged in the region of a suction nozzle cover provided on the suction nozzle. If a part of the thread is cut off, the cut part of the thread is preferably discarded or sucked out.

Another possible measure for reducing the upper thread tension provides for rotating the traverse package with the upper thread in the unwinding direction of the upper thread until the upper thread tension is sufficiently reduced. The thread tension is preferably continuously measured during unwinding of the upper thread from the traverse package, so that the unwinding of the upper thread and thus the thread tension can be correspondingly controlled or adjusted, in particular by a control unit. For this purpose, it is particularly preferred that a motor-driven or pneumatically driven device for receiving the traverse package is rotated in a controlled manner in the direction opposite to the winding direction or in the unwinding direction.

Further measures for reducing the upper thread tension can be to reduce the speed at which the gripper tube enters the thread run and/or to move the gripper tube back out of the thread run before the start of the yarn splicing process. By reducing the speed of the gripper tube when entering the thread run, the gripper tube tensions the thread more slowly, in particular the package with the corresponding thread has more time to unwind and unwinds and lengthens the thread with reduced tension. By pivoting the gripper tube out of the thread run, the thread tension is likewise reduced. Within the scope of the present invention, both measures can be used individually or in combination with each other.

In order to prevent the suction nozzle from pivoting from the suction position to the feed position when it is empty or when at least the upper thread end is uncontrolled, thereby preventing an erroneous splice joint at least when the upper thread end is uncontrolled, a preferred embodiment of the method for forming a splice joint according to the invention provides that the upper thread is fed by the swivellable suction nozzle only if the upper thread or the upper thread end is detected by an upper thread sensor arranged in the area of the suction nozzle. The upper thread sensor may be arranged directly in the area adjacent to the receiving opening for the thread end or at any point along the upper thread feed. Particularly preferably, the suction nozzle searches for the upper thread end until the upper thread end is found and detected by the upper thread sensor.

The limit value of the thread tension, in particular the upper thread tension, can basically be set or defined arbitrarily. The limit value of the upper thread tension can be set via an input means or calculated on the basis of the average value of the preceding cycles.

An embodiment of the working unit of the present invention and a method for joining the lower thread end and the upper thread end implemented in the working unit are described in detail below with reference to the drawings.

FIG. 2 is a schematic side view of an operational unit of the winding machine.

The working unit 1 of the winding machine, shown diagrammatically in FIG. 1, is provided for rewinding the yarn from a number of relatively small yarn supply bobbins 10 onto a large-capacity traverse package 7. Since only a significantly shorter length of yarn is wound onto each of the yarn supply bobbins 10 than is required for the traverse package 7, it is necessary to recombine the yarn several times. The part of the yarn coming from the yarn supply bobbins 10 is called the lower thread 3, the part of the yarn already wound onto the traverse package 7 is called the upper thread 2.

The winding machine is configured as an automatic traverse winder or autoconer. It has a number of identical working units 1 arranged next to each other. The yarn supply bobbins 10 are spinning cops produced by a spinning machine, in particular a ring or air spinning machine, which are automatically fed to the individual working units 1 of the winding machine by a feed unit 11.

A splicing unit 4 is arranged in the working unit 1 so that both ends of the upper thread 2 and the lower thread 3 can be joined. The splicing unit 4 includes a pneumatic yarn splicing device with a splice prism for forming the yarn joint. Furthermore, the splicing unit 4 is arranged outside the yarn path of the yarn to be wound, which is undamaged and does not need to be joined.

In order to provide the upper thread 2 in the event of a yarn break or when the yarn supply bobbin 10 is empty, a suction nozzle 6 is arranged in the working unit 1 of the winding machine so that it can be pivoted between a suction position A and a feed position Z. In the suction position A, the suction nozzle 6 can receive the upper thread 2 or the upper thread end wound on the traverse package 7. Subsequently, in particular after detection of the yarn reception in the suction nozzle 6 by an upper thread sensor arranged in the area of the suction nozzle 6, the suction nozzle 6 is pivoted to the feed position Z and the upper thread 2 is introduced into the splicing unit 4. The suction nozzle 6 is preferably preloaded by a spring element towards the suction position A, so that the suction nozzle 6 automatically reaches the suction position A. In the suction position A, the suction opening of the suction nozzle 6 is located in the area of the surface of the traverse package 7 so as to be able to reliably suck in the free upper thread end.

Between the twill winding package 7 and the splicing unit 4, the upper thread 2 is introduced into the upper thread supply section 9. The thread tension sensor 5 is arranged in the working unit 1 in such a way that when the free upper thread end is fed into the splicing unit 4 by the swivellable suction nozzle 6, the upper thread 2 simultaneously reaches the measuring ring of the thread tension sensor 5, so that the tensile force or tension of the upper thread 2 can be continuously measured before and during the splicing process by the splicing unit 4.

Furthermore, in the region of the upper thread supply 9 and in particular in the thread path of the joined threads, a thread cutting device 12, a thread clearer 13 and a paraffin supply device 14 are arranged.

Between the yarn supply bobbin 10 and the splicing unit 4, the lower thread 3 is introduced into the lower thread feeder 8. This lower thread feeder 8 includes a thread tensioner device 15 in the thread path of the joined thread, a lower thread sensor 16, and a gripper tube 17 which penetrates into the thread path. The gripper tube 17 is pivotally mounted and can be supplied with a negative pressure so that the end of the lower thread 3 can be fed into the area of the splicing unit 4. Furthermore, during the joining of the upper thread 2 and the lower thread 3 in the splicing unit 4, the thread tension can be changed by the gripper tube 17, in particular by pivoting the gripper tube 17.

Furthermore, the working unit 1 of the winding machine has a control unit 18. The control unit 18 is connected to the central control unit and to the control unit of the service unit via the machine bus.

To connect the lower thread 3 and the upper thread 2, the upper thread 2 is first captured from the traverse package 7 by a swiveling suction nozzle 6, which is supplied with negative pressure and which detaches and sucks the upper thread 2 from the traverse package 7 rotating in the unwinding direction. After the upper thread 2 is detected in the suction nozzle 6 by an upper thread sensor, the suction nozzle 6 swivels downwards from the suction position A to the feed position Z and guides the upper thread 2 into the splicing prism of the splicing unit 4. At the same time, the upper thread 2 is placed on the measuring ring of the thread tension sensor 5. The thread tension sensor 5 is located in the thread path above the splicing unit 4. By means of the thread tension sensor 5, the thread tension of the upper thread 2 can now be measured during the insertion process.

If it is determined that the yarn tension has exceeded the preset limit, measures are immediately initiated to bring the yarn tension back within the limits. Alternatively, the yarn splicing process is interrupted and a new yarn capture by the suction nozzle 6 at the suction position A is triggered.

For example, such measures may be a reduction in the speed of the gripper tube 17 when entering the yarn path, a rotation of the gripper tube out of the yarn path or a slight reversal of the traverse package 7 in the unwinding direction. For this purpose, an active and controlled drive of the traverse package 7 is preferably provided, in particular via a speed-controllable drive (not shown). The speed-controllable drive is configured as an electronically communicable DC motor and may be flange-coupled to the package frame or directly integrated in the package frame.

REFERENCE SIGNS LIST 1 Winding machine working unit 2 Upper thread 3 Lower thread 4 Splicing unit 5 Yarn tension sensor 6 Suction nozzle 7 Traverse winding package 8 Lower thread supply section 9 Upper thread supply section 10 Yarn supply bobbin 11 Supply unit 12 Yarn cutting device 13 Yarn clearer 14 Paraffin supply device 15 Yarn tensioner device 16 Lower thread sensor 17 Gripper tube 18 Control unit A Suction position Z Supply position

Claims (15)

A method for producing a spliced joint between an upper thread (2) and a lower thread (3) in an operational unit (1) of a textile machine, comprising the following steps: - supplying at least said upper thread (2) to a splicing unit (4),
- measuring the thread tension of at least the upper thread (2) to be joined by means of a thread tension sensor (5) before the joining;
- comparing the measured thread tension with a preset limit value and decreasing the upper thread tension if the limit value is exceeded;
- joining the lower thread (3) and the upper thread (2) in the splicing unit (4) if the measured thread tension is less than the limit value;
16. A method for forming a splice joint, comprising: The method for forming a spliced joint according to claim 1, wherein the supply of the upper thread (2) to the splicing unit (4) is performed by a suction nozzle (6) to which negative pressure is applied, the suction nozzle (6) being rotatable between a suction position (A) for sucking in the free upper thread end and a supply position (Z) for supplying the free upper thread end to the splicing unit (4). 3. The method for forming a spliced joint according to claim 2, wherein the suction nozzle (6) for supplying the upper thread (2) to the splicing unit (4) captures the free upper thread end in the suction position (A ) in the region of a traverse package (7) for winding the thread, and the suction nozzle (6) draws the upper thread (2) from the traverse package (7) rotating in the unwinding direction. 4. The method for producing a splice joint according to claim 1 , wherein when the upper thread (2) is fed to the splicing unit (4), a free upper thread end is introduced directly into the splicing prism of the splicing unit (4) by means of a swivellable suction nozzle (6). A method for forming a spliced joint according to any one of claims 1 to 4, wherein the measurement of the thread tension of the upper thread (2) is performed during the process of introducing the upper thread (2) into the splicing unit (4). A method for forming a spliced joint according to any one of claims 1 to 5, wherein the upper thread (2) is placed on a measuring ring of the thread tension sensor (5) to measure the thread tension. 7. The method for forming a spliced joint according to claim 1, further comprising the steps of: measuring the thread tension of at least the upper thread (2) to be joined during joining of the thread ends of the lower thread (3) and the upper thread (2) in the splicing unit (4); and reducing the upper thread tension during the joining if it exceeds the limit value. 8. The method for forming a spliced joint according to claim 1, further comprising the step of reducing the upper thread tension by interrupting the supply of the upper thread (2) and/or the connection of the lower thread (3) with the upper thread (2). A method for forming a spliced joint according to any one of claims 1 to 8, in which, when the supply of the upper thread (2) and/or the connection of the lower thread (3) with the upper thread (2) is interrupted, the upper thread (2) is cut and the free end of the upper thread (2) formed in the process is sucked in again in order to reduce the tension in the upper thread. 10. The method for forming a spliced joint according to claim 1, further comprising the step of reducing the upper thread tension by rotating a traverse package (7) carrying the upper thread (2) in the unwinding direction until the upper thread tension is sufficiently reduced. 11. The method for producing a splice joint according to claim 1, further comprising reducing the needle thread tension by reducing the speed at which the gripper tube (17) enters the thread path and/or by the gripper tube (17) performing a short retreating movement out of the thread path before the start of the splicing process. 12. The method for producing a spliced joint according to claim 1, wherein the supply of the upper thread (2) by the suction nozzle (6) is performed only if the upper thread (2) is detected by an upper thread sensor arranged in the area of the suction nozzle (6). The method for forming a spliced joint according to any one of claims 1 to 12, wherein the upper thread tension limit value can be set via an input means or calculated based on the average value of the preceding cycles. A working unit (1) of a textile machine, comprising:
a splicing unit (4) for joining the lower thread (3) and the upper thread (2),
- a lower thread supply (8) and an upper thread supply (9) to said splicing unit (4),
a thread tension sensor (5) is arranged in the upper thread supply (9) so that the thread tension of the upper thread (2) to be joined is measured before the joining;
- an operating unit of a textile machine, further comprising a control unit (18) for comparing the measured thread tension with a preset limit value, characterized in that the upper thread tension is reduced by the control unit (18) if the limit value is exceeded. A winding machine equipped with at least one operating unit (1) according to claim 14.