Method for calibrating a thread storage unit

Abstract

The invention relates to a method for calibrating a thread storage unit (1) that can be arranged at a work station of a textile machine.In order to provide a method for calibrating a thread storage unit (1) which enables its reliable determination of thread tension, the method is provided to include the following calibration steps: - setting a calibration torque of the electric motor (5) in the control system, wherein the calibration torque is less than the maximum torque acting on the thread guide arm (2) due to the magnetic repulsion effect of the coupling elements (6, 7), - activating the electric motor (5) of the drive unit (4) to adjust the thread guide arm (2) with the calibration torque to a rest position against a stop of the thread guide unit (1) by the control system, and - storing the set position of the thread guide arm (2) and the electric motor (5) as the zero position of the thread guide arm (2) and the electric motor (5) in the control system.

Description

[0001] The invention relates to a method for calibrating a thread storage unit that can be arranged at a workstation of a textile machine, comprising a thread guide arm freely rotatable about a pivot axis with a magnetically acting first coupling element arranged at a distance from the pivot axis, a drive unit comprising a controllable electric motor for reversing pivoting of the thread guide arm, wherein the drive unit has a second magnetic coupling element adjustable relative to the first coupling element and magnetically repulsive to the first coupling element, which is arranged on the drive unit in a way that allows it to be brought into operative contact with the first coupling element, 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,A sensor unit for detecting the rotational movement and / or position of the thread guide arm and a control system assigned to the work site for controlling the drive unit and for evaluating the sensor information to identify thread tension exerted on the thread.

[0002] In connection with workstations, particularly spinning and / or winding stations of a textile machine, e.g., spinning machines and winding machines, it is known to position a controlled yarn storage unit upstream of the changing devices along a yarn path for winding bobbins, e.g., conical cross bobbins. These yarn storage units serve to adapt the yarn sag occurring during winding the bobbins to the constant yarn delivery speed, e.g., of a spinning device or spinneret take-up device. In known textile machines, the take-up bobbin is usually held in a pivotally mounted bobbin frame of a winding device downstream of the changing devices during the winding process or bobbin travel and is usually driven by a friction roller via a friction drive or individually.

[0003] Specifically, the winding speed of the take-up bobbin, depending on its wound diameter, corresponds to the constant yarn delivery speed, for example, by the spinning device. During winding, the yarn is laid across the bobbin width, particularly in a crisscross pattern, by means of the changing device. Due to the constant fiber delivery speed, the yarn loosens periodically. Therefore, to maintain the desired yarn tension, it is necessary to compensate for the sag caused by the shortening of the yarn's working path along the yarn's travel.

[0004] Besides compensating for thread sag, it is essential to maintain a largely constant thread tension during the winding process. Prior art, such as EP 4 101 800 A1, already describes the design of thread storage units with a thread guide arm that pivots into the thread path, thus temporarily extending the length of the thread's regular working path by forming loops. The thread guide arm can be pivoted and positioned about a pivot axis transverse to the thread path by means of a controllable electric motor in a drive unit. The electric motor is controlled by a control system that evaluates sensor information from a sensor unit to detect the rotational movement and / or position of the thread guide arm in order to identify the thread tension exerted on the thread.

[0005] Essential for accurately determining the thread tension acting on the thread guide arm using the thread guide unit during operation at the work site is prior calibration of the thread guide unit. This calibration involves recording the relative position of the thread guide arm with respect to the thread storage unit and the position of the electric motor, which is determined by the distance between the coupling elements and the associated motor torque. Such calibration is a prerequisite for identical thread storage units—that is, units with a consistent design, coupling elements, and electric motor—to determine the actual thread tension based on previously recorded characteristic curves for such units.The characteristic curves of the magnetic spring force, from which the control system can deduce the tensile force acting on the thread and consequently the thread tension, are stored in the control system or in a readable storage unit coupled to the control system.

[0006] In currently known methods for calibrating thread storage units with magnetically acting coupling elements, the control system controls the motor in such a way that both the thread guide arm is in contact with a stop on the thread guide unit and the magnetic coupling elements of the thread guide arm and the drive unit are in contact with each other. This position of the thread guide arm and the electric motor is stored in the control system as the zero position.

[0007] However, with this type of calibration, tolerances in the magnetic force and in the mounting of the magnets on the thread guide arm and the drive unit mean that, in this zero position where the magnets of the thread guide arm and drive unit are in contact, the same repulsive forces do not prevail between the coupling elements in every combination thread storage unit. After comparing the ratio of the force applied by the motor to the distance between the coupling elements to determine the effective spring tension with the characteristic curve applicable to all combination thread storage units of the same design in the control system, it results in different combination thread storage units of the same design producing differing thread tension results.

[0008] Based on this, the invention aims to provide a method for calibrating a thread storage unit that enables a reliable determination of the thread tension. The invention achieves this objective through a method with the features of claim 1 and through a working unit with the features of claim 4.

[0009] Advantageous further training opportunities related to the process and the workplace are specified in the respective dependent claims.

[0010] The calibration method according to the invention is characterized by the calibration steps Setting a calibration torque of the electric motor in the control system, wherein the calibration torque is less than the maximum torque acting on the thread guide arm due to the magnetic repulsion effect of the coupling elements, activating the electric motor of the drive unit to adjust the thread guide arm with the calibration torque to a rest position against a stop of the thread guide unit, and storing the set position of the thread guide arm and the electric motor as the zero position of the thread guide arm and the electric motor in the control system.

[0011] The method according to the invention provides that, for its implementation, a calibration torque is set for the electric motor, which is lower than the maximum torque acting on the thread guide arm in the opposite direction to the calibration torque resulting from the magnetic repulsion of the coupling elements. The calibration torque is preferably already stored in the control system, so that the setting of the calibration torque is automatically set or determined by the initiation of the calibration process by the control system.

[0012] By adjusting or selecting the calibration torque according to the invention, an adjustment of the thread guide arm is achieved during the calibration process, causing the thread guide arm to rest against a stop of the thread guide unit, while simultaneously the first coupling element of the thread guide arm and the second coupling element of the drive unit are spaced apart from each other. The resulting position of the electric motor, which is subsequently stored in the control system as the zero position of the electric motor, corresponding to the zero position of the thread guide arm (in which it rests against the stop of the thread guide unit), is thus determined solely by the calibration torque applied by the electric motor and the opposing torque acting on the thread guide arm, generated by the repulsive effect of the coupling elements. Any tolerances, e.g.,The mounting of the coupling elements on the drive unit and the thread guide arm can therefore be disregarded. Based on the zero positions of the thread guide arm and the electric motor determined in this way, the thread tension acting on the thread guide arm can be reliably determined for any position using the characteristic curve stored in the control system or a storage unit connected to the control system for such thread storage units.

[0013] According to a further development of the invention, the calibration torque is set such that the coupling elements have a distance of 1 to 6 mm, preferably 1 to 4 mm, and particularly preferably 1 to 2 mm, in the rest position. Setting or selecting a corresponding calibration torque, if it is stored in the control system or a storage unit connected to the control system, ensures to a particularly high degree that the torque acting opposite to the calibration torque results solely from the repulsive effect of the coupling elements. Starting from the defined zero position, a wide pivot range of the thread guide arm relative to the drive unit is simultaneously available, within which the coupling elements interact with each other and within which, taking into account the characteristic curve, the thread tension can be reliably determined from the existing repulsive effect.

[0014] Calibration of the thread storage unit can, in principle, be carried out after its assembly, i.e., before its installation at the work site, so that the calibration according to the invention ensures that identical thread storage units in the installation position correctly and consistently display the same thread tension for identical load conditions.

[0015] According to a further development of the invention, the thread storage unit is mounted at the workstation before calibration. This embodiment of the invention eliminates the need for a separate control system for operating the thread storage unit and performing the calibration process prior to activation. The further development of the invention allows the thread storage unit to be operated and calibrated with a control system that is arranged separately from the thread storage unit. Thus, according to this further development of the invention, the control system can be located at a workstation encompassing the thread storage unit, in a central machine control system, and / or away from the textile machine.The control system can preferably comprise a control unit and an evaluation and assessment unit, which may be one and the same unit or separate units. Two units can also be implemented as a single unit. Redundant control through the provision of two mutually checking or checkable control systems is also possible.

[0016] Characteristic of the workstation according to the invention with a thread storage unit, which the thread guide arm, which is freely rotatable about a pivot axis, with the magnetically acting first coupling element arranged at a distance from the pivot axis, the drive unit comprising the controllable electric motor for reversing pivoting of the thread guide arm, wherein the drive unit has the second magnetic coupling element, which is adjustable relative to the first coupling element and magnetically repulsive to the first coupling element, and which is arranged on the drive unit in such a way as to be brought into operative connection with the first coupling element, 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,the sensor unit for detecting the rotational movement and / or position of the thread guide arm and the control system assigned to the work site for controlling the drive unit and for evaluating the sensor information to identify a thread tension exerted on the thread, The distinguishing feature is that the control system is designed to carry out the inventive or further developed method described above.

[0017] The workstation according to the invention ensures, by providing the possibility of calibrating the thread storage unit, that the actual thread tension is reliably determined at this point.

[0018] According to a further development of the invention, the thread storage unit is arranged at the work location such that the thread guide arm, in its rest position, is positioned in a location that crosses the thread path, into which the thread guided by the thread guide arm is forced out of the thread path during its travel on the spool. Accordingly, the thread storage unit is arranged with the thread guide arm along the thread path such that the rest position of the guide arm, which corresponds to its zero position as well as the zero position of the electric motor, lies outside the thread path and in the direction in which the thread guide arm forces the thread out of the thread path. This ensures that the thread guide arm can be reset solely by the force exerted by the thread in the direction of its deflection along the thread path.

[0019] An embodiment of the invention is explained below with reference to the drawings. The drawings show: Fig. 1 a perspective schematic view of a thread storage unit according to an embodiment; Fig. 2 in a perspective schematic view an enlarged representation of a partial area of ​​the thread storage unit of Fig. 1 ; Fig. 3 in a perspective schematic view an enlarged representation of the thread storage unit of Fig. 1 without a thread guide arm, Fig. 4 in a perspective schematic representation of the thread guide arm of the thread storage unit of Fig. 1 , and Fig. 5 in a perspective schematic view shown in Fig. 1 The thread storage unit shown is arranged upstream of the paraffin treatment unit.

[0020] Figure 1Figure 1 shows a perspective schematic view of a thread storage unit 1 according to an embodiment, which is connected to a connecting plate 17 for arrangement at a work station, in particular a spinning or winding station, of a textile machine not shown here. Figures 2 to 4 show, in a perspective schematic view, an enlarged representation of a sub-area of ​​the in Figure 1 The thread storage unit 1 shown, as well as a perspective schematic representation of a thread guide arm 2 of this thread storage unit 1.

[0021] The thread storage unit 1 has a thread guide arm 2, which is arranged at the work location in the thread path F of a thread being wound onto a take-up spool, with a thread guide eyelet 13 located at its free end, the thread being guided through the thread guide eyelet 13. To form a thread storage unit, the thread guide arm 2 is pivotably mounted on a drive shaft 16 of an electric motor 5 of a drive unit 4 of the thread storage unit 1, wherein the thread guide arm 2 has a bushing 18 for arrangement at the free end of the drive shaft 16, so that the thread guide arm 2 is mounted on the drive shaft 16 without torque. The bushing 18 is further connected to a holder 9 connected to the thread guide arm 2, which has an opening for receiving a first coupling element 6 designed as a permanent magnet.

[0022] For the loop-forming pivoting of the thread guide arm 2 during operation, the drive shaft 16 of the electric motor 5 is connected to a coupling disk 14, which is arranged coaxially to the drive shaft 16, in a rotationally fixed manner. A carrier 8 is arranged on the coupling disk 14, which has a further bushing 12 for receiving another permanent magnet as a second coupling element 7. The permanent magnets on the thread guide arm 2 and the carrier 8 are aligned with each other such that they exert a mutually repulsive magnetic effect. A rotation of the coupling disk 14 by the reversing electric motor 5 thus causes a corresponding pivoting of the thread guide arm 2 about the drive shaft 16 without contact, which defines a pivot axis S, whereby the electric motor 5 is controlled via connection 19 by a control system (not shown here).

[0023] For position detection of the thread guide arm 2, a sensor unit 3 is arranged above - with reference to the graphic representation - the drive shaft 16 on a housing cover 11 of the housing 10, which with its sensor detecting the swivel angle is arranged 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.

[0024] The sensor unit 3 can reliably determine at least the rotational movement or the position of the thread guide arm 2. By transmitting corresponding sensor information to the control system, deviations of the thread guide arm 2 from the position set by the drive unit 4 can be detected. For example, if the thread tension increases, this causes the thread guide arm 2 to shift towards the second coupling element 7 against the spring force generated by the magnetic repulsion. Based on this, the control system can then shift the coupling disc 14 back. If, for example, the thread tension decreases due to thread sag, this causes the second coupling element 7 to shift towards the thread guide arm 2 by rotating the drive shaft 16 and the coupled carrier 8, including the coupling disc 14 and the permanent magnet.Due to the magnetic repulsion, the thread guide arm 2 moves in the same direction, thus pushing the guided thread away from its thread path F or moving it further away from it, forming or enlarging a thread loop. In this way, a substantially constant thread tension can be achieved and maintained throughout the entire winding process or bobbin travel.

[0025] Figure 5Figure 1 shows a perspective schematic view of an embodiment of the arrangement of the yarn storage unit 1 at the work station (not shown), which can be a spinning or winding station. The yarn storage unit 1 is arranged upstream of a paraffin waxing unit 20, shown only schematically and in part, along a yarn path F, which runs from a yarn delivery device (not shown) towards a changing device (not shown). The paraffin waxing unit 20 has a support 22 below it, on which two yarn guide rollers 21 are rotatably mounted, over which the yarn can be guided along the yarn path F in a partially wrapped manner.The thread storage unit 1 is positioned on the thread path F such that the thread guide arm 2, with its guide eye 13, can pivot into the thread path F to push the running thread out of its path F transversely to the direction of arrangement of the thread guide rollers 21. As a result of being pushed out of its path F by the thread storage unit 1, the thread comes into contact with the thread guide rollers 21, forming a thread loop of defined size between them. The size of the thread loop is varied as needed by the thread storage unit 1, depending on the detected rotational movement or position of the thread guide arm 2, via the control system that drives the electric motor 5 and consequently the thread guide arm 2. This allows the thread storage unit 1 to adjust and regulate the thread tension, which is advantageously kept constant during the bobbin winding process.

[0026] To calibrate the thread storage unit 1, a calibration torque of the electric motor 5 is set via a control system (not shown here), or a calibration torque stored in the control system or in a storage unit connected to the control system is selected. The calibration torque is such that, upon subsequent activation of the electric motor 5 with the calibration torque, the thread guide arm 2 is brought into contact with an inner surface of the housing 10. In the then-established rest position of the thread guide arm 2, the first coupling element 6 is also located at a distance from the second coupling element 7. The position of the thread guide arm 2 and the electric motor 5 is thus determined solely by the calibration torque applied by the electric motor 5 and the magnetic forces acting between the coupling elements 6 and 7.The resulting position of the electric motor 5 and the thread guide arm 2 in the rest position are stored in the control system as the zero position of the thread guide arm 2 and the zero position of the electric motor 5.

[0027] Taking into account a known characteristic curve of the magnetic spring force previously stored in the control system or in a readable storage unit coupled to the control system, the control system can consequently determine the thread tension and thus the thread tension, considering the position of the thread guide arm 2 and the electric motor 5. The calibration of the thread storage unit 1 of a textile machine with multiple workstations ensures reliable detection of the correct thread tension for all workstations. Reference symbol list

[0028] 1 Thread storage unit 2 Thread guide arm 3 Sensor unit 4 Drive unit 5 Electric motor 6 First coupling element 7 Second coupling element 8 Carrier 9 Holder 10 Housing 11 Housing cover 12 Additional bushing 13 Thread guide eyelet 14 Coupling disc 15 Connection element 16 Drive shaft 17 Connection plate 18 Bushing 19 Connection 20 Paraffin device 21 Thread guide roller 22 Holder Thread travel path Swivel axis

Claims

1. A method for calibrating a thread storage unit (1) that can be arranged at a workstation of a textile machine, comprising - a thread guide arm (2) that is mounted in a manner freely rotatable about a pivot axis (S) with a magnetically acting first coupling element (6) arranged at a distance from the pivot axis, - a drive unit (4) having a controllable electric motor (5) for reversibly pivoting the thread guide arm (2), wherein the drive unit (4) has a second magnetic coupling element (7) that is arranged so as to be adjustable relative to the first coupling element (6), acts in a magnetically repelling manner on the first coupling element (6) and is arranged on the drive unit (4) so that it can be brought into operative connection with the first coupling element (6), wherein an adjustment of the second coupling element (7) in the direction of the first coupling element (6) causes a displacement of the first coupling element (6) in the same direction, - a sensor unit (3) for detecting the rotational movement and / or position of the thread guide arm (2) and - a control system assigned to the workstation for controlling the drive unit (4) and for evaluating the sensor information for identifying a thread tension exerted on the thread characterized by the calibration steps of - setting of a calibration torque of the electric motor (5) in the control system, wherein the calibration torque is lower than the maximum torque acting on the thread guide arm (2) due to the magnetic repelling effect of the coupling elements (6, 7), - activation of the electric motor (5) of the drive unit (4) for adjusting the thread guide arm (2) with the calibration torque to a rest position against a stop of the thread guide unit (1) by the control system and - storage of the set position of the thread guide arm (2) and the electric motor (5) as the zero position of the thread guide arm (2) and the electric motor (5) in the control system.

2. The method for calibration according to claim 1, characterized in that the calibration torque is set such that the coupling elements (6, 7) have a distance of 1 to 6 mm, preferably 1 to 4 mm, particularly preferably 1 to 2 mm in the rest position.

3. The method for calibration according to claim 1 or 2, characterized in that, prior to carrying out the calibration, the thread storage unit (1) is mounted at the workstation.

4. A workstation of a textile machine with a thread storage unit (1), which has - a thread guide arm (2) that is mounted in a manner freely rotatable about a pivot axis (S) with a magnetically acting first coupling element (6) arranged at a distance from the pivot axis (S), - a drive unit (4) having a controllable electric motor (5) for reversibly pivoting the thread guide arm (2), wherein the drive unit (4) has a second magnetic coupling element (7) that is arranged so as to be adjustable relative to the first coupling element (6), acts in a magnetically repelling manner on the first coupling element (6) and is arranged on the drive unit (4) so that it can be brought into operative connection with the first coupling element (6), wherein an adjustment of the second coupling element (7) in the direction of the first coupling element (6) causes a displacement of the first coupling element (6) in the same direction, - a sensor unit (3) for detecting the rotational movement and / or position of the thread guide arm (2) and - a control system assigned to the workstation for controlling the drive unit (4) and for evaluating the sensor information for identifying a thread tension exerted on the thread, characterized in that the control system is designed to carry out a method according to one or more of the claims 1 to 3.

5. The workstation according to claim 4, characterized in that the thread storage unit (1) is arranged at the workstation such that the thread guide arm (2) is arranged in the rest position in a position crossing the thread running path (F), into which position the thread guided by the thread guide arm (2) is pushed out of the thread running path (F) during the bobbin travel.

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