Patent Application
20240400341
The invention relates to a method for monitoring the thread run of a running thread at a workstation of a textile machine and a workstation of a textile machine comprising:
In connection with workstations, in particular with spinning and/or winding stations of a textile machine, for example spinning machines and winding machines, it is known to mount a controlled thread storage unit for winding bobbins, for example, conical cross-wound bobbins, upstream from the traversing devices along a thread running path. These thread storage units serve to adapt the thread sags occurring when winding the bobbins at the constant thread feed speed of a spinning device or spinning cop draw-off device, for example. In the known textile machines, the run-on bobbin is usually held in a pivotably mounted bobbin frame of a thread winding device downstream from the traversing device during the winding process or the bobbin travel and is usually driven by a friction roller via a frictional connection or individually. Specifically, the winding speed of the run-on bobbin corresponds to the constant thread feed speed by, for example, the spinning device depending on its wound diameter. During winding, the thread is laid over the bobbin width defined, in particular crosswise, by means of the traversing device. Due to the constant thread feed speed, a periodic loosening of the thread occurs, which is why there is the need to compensate for the sag while shortening the working path of the thread along the thread running path in order to maintain a desired thread tension.
In addition to compensating for the thread sag, it is indispensable to keep the thread tension substantially constant during the winding process. From the prior art, such as for example EP 2 955 142 A1, it is already known to design thread storage units with a thread guide arm which is pivoted into the region of the thread running path and thus temporarily extends the length of the regular working path of the thread in a loop-forming manner. The thread guide arm is usually mounted so as to be pivotable about a pivot axis transversely to the thread path via a controllable electric drive and positionable. The electric drive is actuated via a control system which receives the output information to actuate a thread tension sensor. Depending on the thread tension present during winding, the control system reacts in the form of a defined control of the electric drive and consequently of the thread guide arm, whereby the thread tension can be reduced or increased.
In addition to the thread storage units having a thread guide arm, known workstations furthermore have a pneumatic thread storage which serves to receive a thread loop in a thread storage tube, wherein suction air is made available to the workstation as required for filling the thread storage tube. Applying a suction air flow to the thread storage tube such that a negative pressure arises at the thread inlet opening of the thread storage tube causes the thread extending in front of the thread inlet opening to be sucked into the thread storage tube. The pneumatic thread storage is preferably used at the workstation at the beginning of the working process, for example, while piecing, wherein, for the period of time from starting the thread winding device until the operating speed is reached during normal operation, a thread overlength which cannot be wound because the speed of the run-on bobbin is too low, is initially temporarily stored in the thread storage tube.
Taking into account the thread still in the pneumatic thread storage is essential for efficient and error-free operation of the workstation. In the absence of a suitable sensor system, a filling level of the thread storage tube is calculated mathematically via the difference between, for example, a take-off speed of a spinning station and the rotational speed of the run-on bobbin. Due to different influencing factors, such as slip during acceleration of the run-on bobbin and further factors, the mathematical calculation of the stored thread length only provides an approximate value, which is why the pneumatic thread storage has to be carefully emptied in order to prevent windings on the run-on bobbin with an undesired thread tension. Furthermore, the inconclusive detection of a filled or emptied thread storage results in the need to apply suction air to the pneumatic thread storage for a longer period of time than would theoretically be required, which leads to increased energy consumption.
It is further essential for the operation of the workstation to detect thread breakage, wherein, for this purpose, separate assemblies are usually used at the workstation, namely so-called thread monitors, which detect thread breakage and possibly initiate the necessary process steps at the workstation for further operation of the workstation. The use of separate thread monitors requires increased installation and maintenance effort, for example, due to the necessary connection to the control system of the workstation and a required adjustment and its monitoring for a desired functional reliability.
It is the object of the invention to provide a method for monitoring the thread run of a running thread at a workstation of a textile machine, and a workstation of a textile machine which can be produced and operated in a particularly economical manner.
The invention achieves the object with a workstation having the features of claim 1, and with a method for monitoring the thread run according to the features of claim 11. Advantageous further embodiments of the invention are given in the dependent claims.
Characteristic for the workstation according to the invention is that the thread storage unit is arranged at the workstation such that the control system detects a thread breakage and/or an emptied pneumatic thread storage on the basis of the transmitted sensor information.
According to the invention, the thread storage unit is arranged at the workstation such that by means of the sensor information collected by the sensor unit, i.e., via the thread force acting on the thread guide arm, a rotational movement and/or the position of the thread guide arm, a control system associated with the sensor unit enables the identification of thread breakage and/or the detection of the filling state of the pneumatic thread storage. For example, a significant drop in the thread force acting on the thread guide arm, or a thread force not acting on the thread guide arm, allows the conclusion that a thread breakage exists, so that, for example, the subsequent process steps at the workstation can then be initiated via the control system for a restart. The arrangement according to the invention of the thread storage unit thus also makes it possible to dispense with a separate thread monitor.
The arrangement according to the invention of the thread storage unit at the workstation and thus of the thread guide arm in the region of the thread run furthermore makes it possible to reliably make determinations about the fill level of the pneumatic thread storage via the acting thread force or a thread tension and/or position of the thread guide arm that can be determined therefrom. In the case of a reliably determined emptying of the pneumatic thread storage, suction air operating the pneumatic thread storage can thus directly be switched off, and the working station can thus be operated in an energy-efficient manner.
Additionally or alternatively to determining a thread breakage or an emptied pneumatic thread storage via the thread force acting on the thread guide arm and/or the thread tension determined from the thread force, a thread breakage and/or an emptied pneumatic thread storage can also be reliably identified via the sensor information about the position of the thread guide arm. A combined evaluation of both the position of the thread guide arm and the thread force acting on the thread guide arm enhances in a supplementary manner a reliable detection of an emptied pneumatic thread storage and/or a thread breakage, which enables particularly reliable operation of the workstation.
The control system which is connectable to the sensor unit enables the determination of the thread force, and/or the thread tension determinable therefrom, and/or position of the thread guide arm, via the sensor information collected by the sensor unit. Taking into account known characteristic values stored previously in the control system or in a readable memory unit coupled to the control system, the operating states can be deduced, and a thread breakage and/or an emptied pneumatic thread storage can subsequently be reliably identified.
According to a particularly advantageous embodiment of the invention, it is provided that the control system is designed to deactivate a suction air flow operating the pneumatic thread storage and/or to interrupt a working process taking place at the workstation.
The control system can preferably comprise a control unit and an evaluation and assessment unit. These units may be one and the same unit or units different from one another. Two units having an individual unit can also be realized. Furthermore, the control system can be a component of the thread storage unit or a component separate therefrom. The arrangement of the control system can also be freely selected. The control system can thus be provided in a workstation, which comprises the thread storage unit, in a central machine control system and/or away from the textile machine. A redundant control by providing two such control systems that check or can check each other can also be possible. According to the advantageous embodiment of the invention, the control system is preferably designed to directly control a drive unit regulating the suction air flow and to interrupt this suction air flow in the event of an emptied pneumatic thread storage. The control system according to the further embodiment of the invention can also be provided, in addition or alternatively, to interrupt the working process of the workstation directly so that, in the event of a detected emptied thread storage or a thread breakage, the suction air flow can directly be interrupted, or the process steps to be initiated at the workstation after a thread break can be initiated.
The design of the sensor unit for detecting the thread force, rotational movement and/or position of the thread guide arm is basically freely selectable. According to a particularly advantageous embodiment of the invention, however, the sensor unit has an incremental encoder which is particularly suitable for detecting the position of the thread guide arm and also the thread force acting on the thread guide arm.
According to a development of the invention, it is furthermore provided that the control system is designed to control the drive unit for regulating the thread tension and/or the storage quantity of the guided thread. According to this embodiment of the invention, the control system enables an adjusting movement of the thread guide arm via the control system controlling the drive unit, whereby the thread guide arm can be adjusted in the direction of the thread or in an opposite direction. By pivoting the thread guide arm about the pivot axis into the thread path, a loop-shaped course of the thread is created by the thread guide arm in the region of the thread storage unit, wherein the thread guide arm can preferably come into engagement with the thread in the region between two thread guide rollers or eyelets arranged along a thread running path in order to thereby create a defined loop run.
If a thread excess, which leads to a decrease in the thread tension or a thread force acting on the thread guide arm, arises during the winding process, then said thread excess is received in a loop between the preferably provided pair of thread-guiding rollers or eyelets and the thread guide arm. If in contrast less thread arises during the winding process than requested by the run-on bobbin, for example of the cross-wound bobbin, as a result of which the thread tension or a thread force acting on the thread guide arm increases, then the required amount of thread is released from the loop by a reverse displacement of the thread guide arm, wherein the thread guide arm is pivoted in an opposite direction, pushing the thread away, wherein a pivoting back of the thread guide arm results from the thread force acting on the thread guide arm. The control system thus makes it possible to keep the thread tension constant via the thread guide arm directly by controlling the drive unit in an exact and high frequency, so that a winding process can also be carried out at particularly high winding speeds, wherein the production of cylindrical and also conical run-on bobbins can be carried out particularly reliably.
According to a further embodiment of the invention, the thread guide arm is mounted so as to be freely rotatable and has a magnetically acting first coupling element arranged at a distance from the pivot axis. Furthermore, the drive unit has a second magnetic coupling element, which is adjustably arranged relative to the first coupling element and acts in a magnetically repelling manner on the first coupling element. The second magnetic coupling element is arranged on the drive unit so as to be able to be brought into operative connection with the first coupling element via the drive unit, wherein an adjustment of the second coupling element in the direction of the first coupling element causes a displacement of the first coupling element in the same direction and thus a pivoting of the thread guide arm.
According to this embodiment of the invention, the thread guide arm is now freely rotatable, in particular mounted on the drive shaft of the drive unit, compared to known thread storage units in which the thread guide arm is directly forcibly rotated on the drive shaft by a drive shaft of the drive unit, for example via a fixed bearing, so that the force is transmitted strictly through components which touch one another along the force flow. The rotational force generated by the drive shaft can thereby be transmitted contactlessly to the thread guide arm using magnetically acting means. The first and second coupling elements are oriented relative to one another such that they exert mutually repelling magnetic effects. As a result, during a displacement of the second coupling element by the drive unit in the direction of the first coupling element, due to the repelling effect between the first and second coupling elements, a displacement results of the first coupling element, which takes place corresponding to the direction of movement of the second coupling element, whereby as a result of the connection of the first coupling element to the thread guide arm, the latter is pivoted about the pivot axis. In this respect, the thread guide arm is displaced about its pivot axis without contact via the drive unit based on the set position of the second coupling element arranged on the drive unit.
According to a particularly advantageous embodiment of the invention, it is provided that the second coupling element is arranged on a support adjustable by means of the drive unit, in particular coaxially, about the pivot axis of the thread guide arm. According to this embodiment of the invention, the second coupling element is adjustable about the pivot axis of the thread guide arm, wherein the second coupling element is arranged on a support connected to the drive unit for this purpose. The rotation of the support about the pivot axis of the thread guide arm makes it possible to use particularly space-saving rotary drives for adjusting the second coupling element. Furthermore, rotating the second coupling element, which is particularly preferably arranged at the same distance from the pivot axis as the first coupling element, offers a particularly uniform and reliable adjustment, so that a particularly exact displacement of the thread guide arm by the control system can take place via a displacement of the support.
The arrangement of the first coupling element on the thread guide arm is in principle freely selectable. According to a particularly preferred embodiment of the invention, it is provided that the first coupling element is releasably fastened to the thread guide arm, and/or the second coupling element is releasably fastened to the drive unit. This embodiment of the invention makes it possible to easily exchange the first and/or second coupling element if necessary so that adaptations to different production conditions, which possibly require magnetic effects deviating from one another, can be carried out in a simple manner. Furthermore, maintenance and repair work can be carried out particularly easily and quickly.
The design of the drive unit for displacing the second coupling element, in particular the support, is basically freely selectable, wherein different motor drives can be used here. According to a particularly advantageous embodiment of the invention, however, it is provided that the drive unit has an electric motor, in particular a stepper motor with a drive shaft which is connected to the support in a rotationally fixed manner and on which the thread guide arm is mounted freely rotatable. Particularly preferably, the guide arm has a bearing unit, in particular a bushing element, at a free end, by means of which bearing unit the thread guide arm can be placed on the free end of the drive shaft. The bearing unit is designed to allow the thread guide arm to rotate freely on the free end of the drive shaft, independently of a rotational movement of the drive shaft, i.e., torque-free. Furthermore, the thread guide arm preferably has a thread guide portion at its further free end, in particular a thread guide eye or roller, for contacting and guiding the thread. The lever effect of the thread guide arm can thereby be utilized to the maximum. Other arrangement locations selected as required both of the bearing unit and of the thread guide section along the longitudinal extension axis of the thread guide arm are also conceivable according to a further preferred embodiment.
According to this embodiment of the invention, a particularly exact adjustment of the support about the pivot axis of the thread guide arm is possible via the reversing electric motor. Furthermore, the drive shaft serves to receive the thread guide arm freely rotationally, wherein a freely rotatable bearing or free rotational mobility generally means a torque-free connection between the drive shaft and the thread guide arm so that the drive shaft only serves for pivoting, in particular for pivotable mounting of the thread guide arm, but does not transmit any torque to it. A corresponding embodiment of the thread storage unit also enables its particularly compact design, wherein it is ensured in a particularly reliable manner that a second coupling element arranged on the support can be adjusted about the same circumference around the drive shaft as the first coupling element which is arranged on the thread guide arm at a corresponding distance from the axis of the drive shaft.
The embodiment such that the first coupling element and the second coupling element can achieve a magnetically repelling effect on one another is basically freely selectable. The first and/or second coupling element can thus be designed as electromagnets, the magnetic fields of which are oriented such that they generate a mutually repelling effect. The electromagnets can be controllable via the control system so that different magnetic fields can be generated by them, so that the repelling effect can be set and in particular regulated via the corresponding control system.
According to a particularly advantageous embodiment of the invention, it is provided that the first coupling element and the second coupling element are designed as permanent magnets. The use of permanent magnets as coupling elements, which are arranged correspondingly aligned on the thread guide arm and the support, represents a particularly simple and low-maintenance and economical possibility for providing a magnetic repelling effect. The desired repelling effect can be defined in this case via the selection of the permanent magnets.
The connection of the support to the drive unit, in particular, to a preferably provided drive shaft of an electric motor, can be produced by simple flange connections. According to a development of the invention, however, it is provided that the support is arranged on a coupling disc arranged coaxially to the drive shaft and connected to the drive shaft in a rotationally fixed manner. The use of a coupling disk ensures a particularly reliable displacement of the support and of the second coupling element connected to the support about the pivot axis of the thread guide arm. The coupling disc can rest against a corresponding counter surface of an advantageously provided electric motor for flat guidance.
According to a further aspect of the present invention, a method for monitoring the thread run of a running thread at a workstation of a textile machine according to one of the embodiments described above is proposed. The sensor unit transmits sensor information about the thread force acting on the thread guide arm, a rotational movement and/or a position of the thread guide arm to a control system associated with the workstation. Based on the transmitted sensor information, the control system evaluates the thread force acting on the thread guide arm, rotational movement and/or position of the thread guide arm. In the event of a detected thread breakage, the control system interrupts the working process at the workstation or, in the event of a detected emptied pneumatic thread storage, deactivates the suction air flow operating the same.
An exemplary embodiment of the invention is explained below with reference to the drawings. In the drawings:
The thread storage unit 1 has a thread guide arm 2 which is arranged at the workstation 20 with a thread guide eye 13 arranged at its free end in the thread path of a thread 23 to be wound onto a run-on bobbin of a thread winding device 22, wherein the thread 23 is guided through the thread guide eye 13. In order to form a thread storage, the thread guide arm 2 is mounted pivotably on a drive shaft 16 of an electric motor 5 of a drive unit 4 of the thread storage unit 1, wherein for this purpose, the thread guide arm 2 has a bushing 18 for arrangement on the free end of the drive shaft 16, so that the thread guide arm 2 is mounted on the drive shaft 16 in a torque-free manner. The bushing 18 is furthermore connected to a holder 9 connected to the thread guide arm 2, which holder has an opening for receiving a first coupling element 6 designed as a permanent magnet.
The drive shaft 16 of the electric motor 5 is non-rotatably connected to a coupling disk 14, which is arranged coaxially to the drive shaft 16 for the thread guide arm 2 to pivot to form a loop during operation. A support 8, which has a further bushing 12 for receiving a further permanent magnet as the second coupling element 7, is arranged on the coupling disc 14. The permanent magnets on the thread guide arm 2 and the support 8 are oriented relative to one another such that they exert a magnetic repelling effect on one another. A rotation of the coupling disc 14 over the reversing electric motor 5 thus causes a corresponding contact-free pivoting of the thread guide arm 2 about the drive shaft 16, which defines a pivot axis S, wherein the electric motor 5 is controlled via a control system (not shown here) via the connection 19.
A sensor unit 3 arranged above—in relation to the drawing—the drive shaft 16 on a housing cover 11 of the housing 10 serves to detect the position of the thread guide arm 2, and is arranged with its sensor detecting the pivot angle coaxially to a connecting element 15 connected to the thread guide arm 2, which in turn extends in the longitudinal axis direction of the drive shaft 16.
The sensor unit 3 can be used to particularly reliably determine at least the thread force acting on the thread guide arm 2, the rotational movement or the position of the thread guide arm 2, and to detect deviations of the thread guide arm 2 from the position set by the drive unit 4 by transmitting corresponding sensor information about the above to the control system. If, for example, the thread force or the thread tension increases, then this causes a displacement of the thread guide arm 2 in the direction of the second coupling element 7 against the spring force generated by the magnetic repelling effect. On the basis of this, a return displacement of the coupling disc 14 can then take place via the control system. If, for example, the thread force or the thread tension decreases while a thread sagging, then this causes a displacement of the second coupling element 7 through a rotation of the drive shaft 16 and the support 8 coupled thereto together with the coupling disc 14 and the permanent magnet in the direction of the thread guide arm 2. Due to the magnetic repelling effect, the thread guide arm 2 is moved in the same direction, whereby the guided thread 23 is pushed out of its thread path or further away therefrom, and a thread loop is formed or enlarged. A substantially constant thread tension can thus be achieved and ensured during the entire winding process or bobbin travel.
Downstream from the thread feeding device 21—relative to the thread running direction F—a draw-off device 26 is arranged which, with the aid of two draw-off rollers 27a, 27b forming a draw-off roller pair, draws the thread 23 exiting from the thread feeding device 21 out of the thread feeding device 21 and transports it in the direction of the thread winding direction 22. A pneumatic thread storage 28 with a thread storage tube 29 is in turn downstream from the draw-off device 26. The thread storage unit 1 is arranged downstream from the pneumatic thread storage 28 along the thread path, wherein the thread storage unit 1 is positioned on the thread path such that the thread guide arm 2 can pivot into the thread path in order to push the running thread 23 out of its thread path. As a result of being pushed out of thread path by the thread storage unit 1, the thread 23 comes into contact with thread guide rollers (not shown here) arranged in the region of the thread storage unit 1, whereby a thread loop of a defined size is formed therebetween. The size of the thread loop is varied as required by means of the thread storage unit 1 depending on the position of the thread guide arm 2 via the control system, which controls the electric motor 5 and consequently the thread guide arm 2, for adjusting and regulating a thread tension that is advantageously kept constant for the bobbin travel.
The arrangement of the thread storage unit 1 in the region of the pneumatic thread storage 28 makes it possible to identify an emptying of the pneumatic thread storage 28 and/or a thread breakage via the control system connected to the sensor unit 3 on the thread storage unit 1 by collecting the sensor information through the sensor unit 3 on the position of the thread guide arm 2 and/or the thread force applied to the thread guide arm 2 by the thread 23, so that a cumbersome, theoretical determination of the thread length in the thread storage tube 29 and a separate thread monitor for identifying a thread breakage can be dispensed with. For this purpose, the control system compares the sensor information with known characteristic values, which are stored previously in the control system or in a readable memory unit coupled to the control system, from which values the operating states can be deduced. In the case of an emptied thread storage tube 29, the control system can be used to directly deactivate the drive unit generating the suction air flow in the thread storage tube 29.
| Number | Date | Country | Kind |
|---|---|---|---|
| 504357 | May 2023 | LU | national |
