Method for operating a work station of a spinning machine and work station

Abstract

The invention relates to a method for operating a work station (1) of a spinning machine, wherein during normal operation a thread (3) is drawn from a spinning unit (4) at a drawing speed, wherein the thread (3) is monitored with regard to at least one thread parameter by means of a mass sensor (5), wherein the thread (3) is wound onto a bobbin (7) by means of a winding device (6) at a winding speed, so that a bobbin (8) is formed, wherein the thread (3) is moved back and forth along a traverse width (CB) during the winding onto the bobbin (7), wherein a stop sequence is initiated when a thread error-related anomaly (F) deviating from a nominal value of the at least one thread parameter is detected by the mass sensor (5). The winding speed is reduced during the stop sequence, wherein a thread loop (S) is formed as a result of the speed difference between the winding speed and the drawing speed thus caused. The invention also relates to a work station (1) of a spinning machine.

Description

TECHNICAL FIELD

[0001] The invention relates to a method for operating a work station of a spinning machine, wherein a thread is drawn from a spinning unit at a drawing speed during normal operation, wherein the thread is monitored with regard to at least one thread parameter by means of a mass sensor, wherein the thread is wound onto a bobbin by means of a winding device at a winding speed, thereby forming a bobbin, wherein the thread is moved back and forth along a traverse width during the winding onto the bobbin, wherein a stop sequence is initiated when a thread error-related anomaly deviating from a nominal value of the at least one thread parameter is detected by the mass sensor. The invention also relates to a work station of a spinning machine. BACKGROUND

[0002] General-purpose spinning machines and methods for operating a work station of such a spinning machine are known in the prior art. The spinning machine can be configured as a jet spinning machine or a rotor spinning machine, for example. The object here is to initiate a stop sequence in the event of an anomaly deviating from a nominal value of at least one thread parameter.

[0003] For example, patent document DE 102015110486 A1 discloses a method for operating a spinning station of a spinning machine, wherein a stop sequence is initiated when a predetermined anomaly of the monitored thread parameters deviating from at least one nominal value is detected. In terms of the stop sequence, the spinning unit and the winding unit are stopped in such a way that the last resulting thread section is not completely deposited onto a bobbin located in the winding device. Usually, the thread section in which the anomaly of the thread parameters was detected is followed by an indeterminate length of subsequent thread winding onto the bobbin. This indeterminate length of subsequent thread then has to be unwound and cut off. This results in a large amount of waste thread. SUMMARY

[0004] The object of the invention is to overcome the disadvantages known from the prior art. The object of the invention is in particular to propose a method for operating a work station of a spinning machine and a work station, in which the thread end is more easily found, the thread winding onto the bobbin is improved and / or the waste thread is reduced.

[0005] The solution according to the invention to achieve the above object is a method for operating a work station of a spinning machine and a work station having the features of the independent claims.

[0006] The invention proposes a method for operating a work station of a spinning machine, from which a yarn is drawn at a drawing speed from a spinning unit during normal operation. The spinning machine is preferably an air-jet spinning machine or a rotor spinning machine. Depending on the type of spinning machine employed, the spinning unit comprises for example a vortex chamber or a rotor and produces a yarn from a fed fibre material. The yarn is subsequently drawn from the spinning unit by means of a drawing device. The "drawing speed" is to be understood as the speed at which the yarn is drawn from the spinning unit. The work station generally also comprises further elements required for yarn production, for example a drafting system for drafting and / or an opening roller for opening a fibre strand.

[0007] After leaving the outlet of the spinning unit, the yarn is monitored with regard to at least one yarn parameter by means of a quality sensor. The yarn parameter is for example the thickness, the hairiness or a further parameter characterising the quality of the yarn or fluctuations thereof over time.

[0008] Subsequently, the yarn is wound onto a bobbin by means of a winding device at a winding speed, thereby forming a cop, the yarn being moved back and forth along a traverse width as the yarn is wound onto the bobbin. The work station has a traversing device for moving the yarn back and forth along the traverse width. The traverse width is the distance between two turnaround points of the traversing device. The term "bobbin" is to be understood as the body onto which the yarn is wound. The term "cop" is to be understood as the combination of the bobbin and the yarn located thereon. The "winding speed" is to be understood as the speed at which the yarn is wound onto the bobbin or the surface of the cop. The winding speed is the speed at which the yarn touches the bobbin or the cop a moment before. The winding speed is mainly dependent on the rotational speed of the bobbin or the cop, the outer diameter of the cop, the traverse width and / or the traverse frequency at which the traversing device is moved along the traverse width.

[0009] When a yarn error-related anomaly deviating from the nominal value of the at least one yarn parameter is detected by means of the quality sensor, a stop sequence is initiated. The yarn section in which the yarn error-related anomaly deviating from the nominal value of the at least one yarn parameter occurs can be referred to as a defect. The "stop sequence" is to be understood as a sequence in which the normal operation of the work station is stopped. The stop sequence is the chronological order of the different operations when stopping the normal operation. The individual elements such as the spinning unit, the winding device, the drawing device and / or the traversing device can be stopped step by step or simultaneously. In order to monitor the at least one yarn parameter of the yarn after leaving the outlet of the spinning unit, the quality sensor can be arranged between the spinning unit and the drawing device. Additionally or alternatively, the quality sensor can be arranged between the drawing device and the winding device.

[0010] In the method, the winding speed is reduced during the stop sequence, as a result of which a speed difference between the winding speed and the drawing speed is caused which forms a loop of yarn. The drawing speed is substantially constant and / or the reduction of the drawing speed is less than the reduction of the winding speed, so that a loop of yarn is formed. By reducing the winding speed during the stop sequence, the winding of the yarn is further slowed down after the detection of a yarn error-related anomaly deviating from the nominal value of at least one yarn parameter. Flaws in the yarn are thus not wound or only slowly wound onto the bobbin or onto the winding surface. Furthermore, the position of the flaw can be more precisely located between the quality sensor and the winding device and / or on the winding, as a result of the reduced winding speed. The yarn tension remains approximately constant when the yarn is slowly wound onto the bobbin during the stop sequence, despite the speed difference caused by the loop of yarn. This can compensate for fluctuations in the yarn tension caused by the reduction of the winding speed and / or the reciprocating movement of the traversing device along the traversing width at the traversing frequency.

[0011] According to the application, in the method the traversing width is reduced during and / or after the reduction of the winding speed. As a result of the reduction of the traversing width, the yarn is deposited onto the bobbin or onto the winding surface within this reduced traversing width. This ensures that the flaw is deposited onto the winding within this traversing width. The flaw can thus be more easily found. The reduction of the yarn tension caused by the reduction of the traversing width can be compensated for by enlarging the loop of yarn. This ensures a constant yarn tension while the traversing width is reduced.

[0012] With the reduction of the winding speed and / or the reduction of the traversing width, the yarn is severed in the region of the loop of yarn, wherein the resulting winding-side end of the yarn is guided in the direction of the winding at the winding speed. If the yarn is severed in the region of the loop of yarn as the winding speed is reduced, the end is slowed down in the direction of the winding. As a result of the reduction of the winding speed, the end can be stopped before it is deposited, in particular in the pick-up position. This makes it easier to find and / or pick up the end in the subsequent joining process. If the yarn is additionally or alternatively severed in the region of the loop of yarn after the reduction of the traversing width, the position of the flaw and / or the end can also be limited in width when it is guided in the direction of the winding.

[0013] It is also advantageous if the loop of yarn is formed and / or severed in a temporary storage. The temporary storage preferably works pneumatically and sucks the yarn by means of negative pressure. By means of the temporary storage, it can be ensured that the yarn tension is maintained. If the loop of yarn is severed in the temporary storage, the winding-side end can be discharged from the temporary storage against the direction of the suction action when the yarn is moved in the direction of the winding. By means of the temporary storage, in particular a pneumatically working temporary storage, the drawing-side end can be discharged or sucked away.

[0014] For cutting the yarn, a yarn breakage device is advantageously arranged in the temporary storage. The yarn sucked into the temporary storage by the underpressure is subsequently broken off by the yarn breakage device. By arranging the yarn breakage device in the temporary storage, a clear yarn end can be produced, in particular by maintaining the yarn tension. Such a clear yarn end can simplify the subsequent search, picking up and / or joining of the yarn. Furthermore, the advantage of arranging the yarn breakage device in the temporary storage is that a compact workstation can be created.

[0015] It is also advantageous to reduce the traverse width to approximately zero, whereby the yarn is deposited on the bobbin in the manner of at least one parallel loop. Here, reducing the traverse width to approximately zero is understood to mean that the yarn can be deposited on the bobbin surface in the manner of approximately parallel loops. The loops of the yarn are arranged next to one another in a narrow width, thereby forming parallel loops. The defect is deposited on the bobbin surface in the area of the at least one parallel loop. The bobbin-side yarn end is preferably stopped before it is deposited on the bobbin. By depositing the parallel loops of the yarn, the yarn can be rewound again simply and the yarn can be fed back to the spinning unit in the sequence of stops during the joining process.

[0016] It is also advantageous for the at least one parallel loop to be deposited in the centre of the bobbin. The traverse width, which is preferably reduced to approximately zero, can be formed in the centre of the bobbin. The defect is deposited on the bobbin surface in the centre in the area of the at least one parallel loop. The bobbin-side yarn end is preferably stopped before it is deposited on the bobbin, the picking-up position of the bobbin-side yarn end being arranged substantially in the centre of the bobbin. Since the picking-up position of the bobbin-side yarn end is central, the yarn end can be more easily searched for and / or picked up.

[0017] It is advantageous for the yarn speed and / or the winding speed to be reduced to a stop after the yarn has been cut and / or after the yarn monitor has detected the passage of the bobbin-side yarn end. The yarn monitor is preferably arranged between the drawing-off device and the winding device and / or between the temporary storage, in which the thread loop is formed, and the winding device. In this way, the bobbin-side yarn end can be detected before it is deposited on the bobbin. Additionally or alternatively, the traversing device can be deactivated. In this way, the sequence of stops can be completed. Subsequently, the defect can advantageously be removed and / or the joining process can be started.

[0018] It is also advantageous for the winding device to continue to run after the yarn monitor has detected the passage of the bobbin-side yarn end until the yarn segment, which exhibits the error-related anomaly, is deposited on the surface of the bobbin and / or the bobbin-side yarn end is arranged in the picking-up position. In this way, a consistently unchanged picking-up position can be ensured.

[0019] The invention also relates to a workstation of a spinning machine comprising a doffing device for drawing off a yarn from a spinning unit, a quality sensor for monitoring the yarn with respect to at least one yarn parameter, a winding device for winding the yarn onto a bobbin and a traversing device for reciprocating the yarn along a traversing width during winding. The workstation has a control unit or is operatively connected to a control unit which is designed to operate the workstation according to the above, wherein the features can exist individually or in any combination.

[0020] Advantageously, the workstation has a temporary storage, preferably pneumatically working, for forming a loop of the yarn.

[0021] Further advantageously, the temporary storage has a yarn breaking device for cutting the yarn in the region of the loop of the yarn. BRIEF DESCRIPTION OF DRAWINGS

[0022] Further advantages of the invention are described below in connection with embodiments. In the drawings:

[0023] Figures 1 to 4 A schematic diagram of a method for operating a workstation of a spinning machine according to the invention is shown. DETAILED DESCRIPTION

[0024] Figure 1 A schematic front view detail of a workstation 1 of a spinning machine during normal operation is shown. During normal operation, a yarn 3 is drawn off from a spinning unit 4 by a doffing device 2 at a doffing speed. The doffing device 2 is preferably configured in the form of a doffing roller pair. In the shown embodiment, the spinning unit 4 is a jet spinning machine's spinneret with a vortex chamber, wherein the filaments of a fiber material are twisted into the yarn 3 by means of an air vortex. The present figure does not show the fiber material feed which is generally realized in a jet spinning machine by means of a drafting system.

[0025] Alternatively, if the workstation 1 is a workstation 1 of a rotor spinning machine, the fiber material is generally opened into its individual filaments using an opening device. Instead of a vortex chamber, the spinning unit 4 has a rapidly rotating rotor cup for forming the yarn 3.

[0026] After leaving the spinning unit 4, the yarn 3 is monitored with regard to at least one yarn parameter by means of the mass sensor 5. Subsequently, the presence of the yarn 3 can be monitored additionally by means of the yarn monitor 15. Subsequently, the yarn 3 is wound onto a bobbin 7 by means of the winding device 6 at a winding speed, thereby producing a winding 8. In order to additionally guide the yarn 3, a guide element 9 can be arranged between the yarn monitor 15 and the winding device 6. In order to produce a cross-wound winding, the yarn 3 is moved back and forth along a traverse width CB by means of the traversing device 10 as the yarn 3 is wound onto the bobbin 7 or onto the surface of the winding 8. In the embodiment shown, the traverse width CB can be selected during normal operation of the work station 1 such that the traversing device 10 can distribute the yarn 3 evenly over the winding width SB on the bobbin 7 or on the surface of the winding 8. To this end, the traverse width CB is essentially equal to the winding width SB during normal operation of the work station 1.

[0027] Furthermore, the work station 1 has a control unit 11. The control unit 11 is designed such that it can operate the components of the work station 1 in accordance with the respective stored specifications, in particular in accordance with the above and / or below. In addition or alternatively, the control unit 11 can be arranged centrally in the spinning mill and operate one or more work stations 1 of the spinning mill in accordance with these specifications. The control unit 11 is in operative connection with the work station 1.

[0028] If at least one yarn error-related exception F occurs during normal operation of the work station 1 in which a yarn parameter deviates from the nominal value, as shown in Figure 2 the stop sequence is initiated after the mass sensor 5 has detected the yarn error-related exception F.

[0029] In the following description of the embodiment shown in Figures 2 to 4 the same and / or at least equivalent features to the aforementioned embodiments of Figure 1 in terms of design and / or mode of operation can use the same reference signs. If these features are not explained again specifically, their design and / or mode of action correspond to the design and mode of action of the already described features.

[0030] When the stop sequence is initiated, as shown in Figure 2 a yarn loop S is formed by reducing the winding speed and thus the speed difference between the winding speed and the doffing speed. The winding speed depends primarily on the rotational speed of the bobbin 7 or the winding 8 introduced by the winding device 6 and on its diameter. The doffing speed depends primarily on the rotational speed of the doffing roller pair of the doffing device 2.

[0031] The work station 1 has a buffer 12 for forming the yarn loop S. For sucking the yarn loop S, the buffer 12 is preferably pneumatically operated. As shown in the figure embodiment, the buffer 12 is preferably arranged between the mass sensor 5 and the yarn monitor 15 or between the doffing device 2 and the yarn monitor 15. Due to the slower winding speed, the yarn error-related anomaly F is slowed down in the direction of the winding package 8.

[0032] During and / or after the winding speed is reduced, the traverse width CB is reduced. Figure 3 This stopping sequence moment is shown, in which the traverse width CB is reduced to approximately zero. By reducing the traverse width CB to approximately zero, at least one parallel winding PW of the yarn 3 is produced on the surface of the winding package 8. Additionally, the yarn loop S can be enlarged by reducing the traverse width CB.

[0033] With the reduction of the winding speed and the reduction of the traverse width CB, the yarn 3 is cut in the area of the yarn loop S by means of the yarn breaking device 13. The resulting winding side end 14, together with the yarn error-related anomaly F, is further guided in the direction of the winding package 8 at the winding speed. Figure 4 This stopping sequence moment is shown. After the yarn 3 has been cut and / or the winding side end 14 has passed the yarn monitor 15, the winding speed is reduced to a standstill. As shown in the figure embodiment, the winding side end 14 is stalled before it reaches the surface of the winding package 8. Figure 4 The position of the winding side end 14 shown is called the pick-up position. The pick-up position is arranged substantially in the center of the sleeve 7 or the winding package 8. The yarn error-related anomaly F is wound onto the surface of the winding package 8 in the area of at least the parallel winding PW. In addition, the production of the yarn 3 can be set by the spinning unit 4, after which the doffing speed can be reduced to a standstill. The resulting yarn 3 after the yarn 3 has been cut can be sucked by means of the buffer 12. The stopping sequence is then ended.

[0034] After the stopping sequence, the winding side end 14 can be prepared for the pick-up. For this purpose, the winding side end 14 is picked up at the pick-up position by means of the work station's own means and / or by means of a service robot, at least one parallel winding PW is unwound from the winding package 8, the yarn error-related anomaly F is eliminated and returned to the spinning unit 4. After the pick-up has been completed, the work station 1 can resume normal operation.

[0035] The invention is not limited to the embodiments shown in the figures and described in the text. It is equally possible to encompass the combinations of features represented and described in the different embodiments within the scope of the claims.

[0036] List of reference signs

[0037] 1 work station

[0038] 2 doffing device

[0039] 3 Yarn

[0040] 4 Spinning unit

[0041] 5 Mass sensor

[0042] 6 Twisting device

[0043] 7 Spool

[0044] 8 Bobbin

[0045] 9 Guide element

[0046] 10 Traverse device

[0047] 11 Control unit

[0048] 12 Buffer

[0049] 13 Yarn breakage device

[0050] 14 Twisting side thread

[0051] 15 Yarn monitor

[0052] CB Traverse width

[0053] SB Twisting width

[0054] F Yarn error-related anomaly

[0055] S Yarn loop

[0056] PW Parallel winding

Claims

1. Method for operating a work station (1) of a spinning machine, wherein during normal operation, drawing a thread (3) from a spinning unit (4) at a drawing speed, wherein the thread (3) is monitored with regard to at least one thread parameter by means of a mass sensor (5), wherein the thread (3) is wound onto a bobbin (7) at a winding speed by means of a winding device (6) so that a bobbin (8) is formed, wherein the thread (3) is moved back and forth along a traverse width (CB) during winding onto the bobbin (7), wherein, when a thread error-related anomaly (F) deviating from a nominal value of the at least one thread parameter is detected by means of the mass sensor (5), a stop sequence is initiated, wherein the winding speed is reduced during the stop sequence, wherein, as a result of the speed difference between the winding speed and the drawing speed thus caused, a thread loop (S) is formed, characterized in that the traverse width (CB) is reduced during and / or after the reduction of the winding speed, the thread (3) is severed in the area of the thread loop (S) with the reduction of the winding speed and / or the reduction of the traverse width (CB), wherein a winding-side thread end (14) thus caused is guided in the direction of the bobbin (8) at the winding speed.

2. The method of claim 1, wherein, the thread loop (S) is formed and / or severed in a temporary storage (12).

3. The method of claim 1, wherein, the traverse width (CB) is reduced to a negligible value, so that the thread (3) is deposited on the bobbin (8) in the form of at least one parallel winding (PW).

4. The method of claim 3, wherein, the at least one parallel winding (PW) is deposited centrally on the bobbin (8).

5. The method according to any one of claims 1-4, characterized in that, after the thread (3) has been severed and / or after the winding-side thread end (14) has been detected by a thread monitor (15), the drawing speed and / or the winding speed is reduced to a standstill.

6. The method of claim 5, wherein, after the winding-side thread end (14) has been detected by the thread monitor (15), the winding device (6) continues to operate until a thread section of the thread error-related anomaly (F) is deposited on the surface of the bobbin (8) and / or the winding-side thread end (14) is arranged in a pickup position.

7. Work station (1) of a spinning machine, comprising a drawing device (2) for drawing a thread (3) from a spinning unit (4), a mass sensor (5) for monitoring the thread (3) with regard to at least one thread parameter, a winding device (6) for winding the thread (3) onto a bobbin (7), and a traversing device (10) for moving the thread (3) back and forth along a traverse width (CB) during winding, characterized in that the work station (1) has or is in operative connection with a control unit (11) which is designed such that the work station (1) is operated according to the method of any one of claims 1 to 6.

8. A station (1) according to claim 7, characterized in that the work station (1) has a temporary storage (12) for forming a thread loop (S).

9. - The station (1) according to claim 8, characterized in that, the temporary storage (12) is pneumatically operated.

10. - The station (1) according to claim 8 or 9, characterized in that, The temporary storage (12) has a yarn breakage device (13) for cutting off the yarn (3) in the region of the yarn loop (S).

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