Whisker pretreatment device

Abstract

The invention relates to a drafting device for transporting a sliver towards an inlet opening of a vortex chamber of a air-jet spinning device and to a method for operating a drafting device having an output roller pair and at least one further drafting roller pair and / or belt roller pair, by means of which a sliver for producing a yarn is fed to a vortex chamber of an air-jet spinning device of a spinning station of an air-jet spinning machine, wherein the output roller pair is drivable independently of the at least one further drafting roller pair and / or belt roller pair. In order to provide a method for operating a drafting device having an output roller pair and at least one further drafting roller pair and / or belt roller pair and a drafting device, which achieves a reliable pre-treatment of the end of the sliver before the start of spinning, it is proposed that the output roller pair is driven at a set combing speed after a spinning interruption in order to comb the end of the sliver and that the at least one drafting roller pair and / or belt roller pair, which is arranged upstream of the output roller pair in the direction of sliver transport, is stopped or is operated at a holding speed corresponding to the combing speed, which holding speed is at most 10% of the combing speed.

Description

Technical Field

[0001] The present invention relates to a drafting device for conveying sliver toward the inlet of the vortex chamber of an air-jet spinning machine, and a method of operating a drafting device having an output roller pair and at least another drafting roller pair and / or a belt roller pair, wherein the drafting device is used to feed sliver for yarn production into the vortex chamber of the air-jet spinning machine at the spinning station of the air-jet spinning machine, wherein the output roller pair is driveable independently of the at least another drafting roller pair and / or belt roller pair. Background Technology

[0002] In the prior art, various technical solutions for drafting devices of the same type have been disclosed, as well as various technical solutions for methods of operating drafting devices at the spinning station of an air-jet spinning machine. At the spinning station of such an air-jet spinning machine, the drafting device is used to feed the sliver into the vortex chamber of the air-jet spinning device at the spinning station, wherein the sliver is pre-drafted.

[0003] During the spinning process, defects sometimes occur, including yarn segments whose parameters (such as yarn thickness, hairiness, and yarn strength) differ from the set nominal values. These defects are identified by yarn sensors and need to be removed during a cleaning cut (Reinigerschnitt) that interrupts the spinning process. Yarn breaks can also occur during spinning, requiring the yarn ends to be reattached to the sliver fed into the air-jet spinning machine via the drafting device in the vortex chamber.

[0004] To implement the yarn start-up process, a yarn pick-up device, either located at the spinning station or adjacent to it, particularly in a manner movable on an air-jet spinning machine, is needed to pick up the yarn end wound onto the take-up bobbin. This allows the yarn end to be fed into the vortex chamber of the air-jet spinning machine during the spinning process in the opposite direction to the original yarn path, so that it can be connected to the fed sliver. To pre-treat the yarn end for connection to the fed sliver, it needs to be pre-treated before start-up. For this purpose, a yarn pre-treatment device is provided downstream of the vortex chamber along the yarn path, used to cut the yarn end to a predefined length and untwist it for connection to the fed sliver. After untwisting the yarn end, the clamps holding the yarn end in the yarn pre-treatment device are released, for example by a blower, and the yarn end is fed into the vortex chamber and held there.

[0005] In the subsequent yarn-forming process, the sliver is fed into the vortex chamber through the output roller pair using the drafting device. In the vortex chamber, the sliver is connected to the free yarn end placed there while forming a yarn, and then the sliver is drawn out from the vortex chamber by the drawing device.

[0006] At the start of the spinning process, the drafting device is activated first, feeding the sliver toward the vortex chamber. The lead-out device is activated only after the drafting device has started, creating a dwell time in the vortex chamber at the beginning of the spinning process. During this dwell time, the sliver fed in by the drafting device is connected to the lead-out in the vortex chamber. After the dwell time is exhausted, both the lead-out device and the output roller pair are accelerated to the set lead-out speed, at which the spinning process continues.

[0007] Careful pretreatment of the free end of the sliver is crucial for ensuring error-free connection between the thread end and the sliver during the topping process. However, known drafting devices and methods for sliver pretreatment using drafting devices can only provide limited adjustment of the sliver end before the topping process. Summary of the Invention

[0008] In view of this, the object of the present invention is to provide a method for operating a drafting device having an output roller pair and at least another drafting roller pair and / or a belt roller pair, and a drafting device by means of which reliable pretreatment of the sliver ends can be performed before the sliver forming process.

[0009] The present invention provides a solution for achieving the above-mentioned objectives, including a method, a stretching device, advantageous improvements, and further embodiments.

[0010] The method of the present invention is characterized in that, after spinning is interrupted, the output roller pair is driven at a set combing speed to comb the sliver, and at least one drafting roller pair and / or belt roller pair located upstream of the output roller pair along the sliver conveying direction is stopped or made to run at a holding speed corresponding to the combing speed, the holding speed being a maximum of 10% of the combing speed.

[0011] In conventional spinning operations, the output roller pair and the lead-out device of the drafting unit have a consistent production speed, known as the lead-out speed. At least one drafting roller pair and / or belt roller pair located upstream of the output roller pair along the yarn travel direction has a lower production speed due to system factors, in order to achieve the desired drafting of the sliver within the drafting unit.

[0012] According to the method of the invention, the output roller pair, which can be driven independently of at least one other drafting roller pair and / or belt roller pair, is driven at a set carding speed, while the at least one other upstream drafting roller pair and / or belt roller pair is stationary or operates at a small holding speed, which is at most 10% of the carding speed. This carding operation of the drafting device does not cause the sliver to be fed toward the vortex chamber of the air-jet spinning device, or causes only a very small amount of feeding. Specifically, particularly when the drafting roller pair and / or belt roller pair is stationary and the output roller pair operates at a set carding speed, this carding process adjusts the sliver end to provide optimal pretreatment for the sliver end forming process at the free thread ends located in the vortex chamber.

[0013] According to an improved embodiment of the invention, when the drafting device is activated during the sliver formation process, the output roller pair is driven in a manner that precedes the activation of at least one other drafting roller pair and / or belt roller pair. Based on this technical solution of the invention, fluctuations during the activation of the output roller pair can be avoided, which could cause the fibers to not be fed at the speed set by the other drafting devices, potentially leading to additional drafting of the sliver or fiber accumulation.

[0014] In principle, the output roller pair can be started and the pretreated sliver fed into the vortex chamber of the air-jet spinning device after the carding process of the output roller pair is run independently of the stationary pair or only at the corresponding holding speed. However, according to another embodiment of the invention, the drafting device is stopped after carding and then started to generate the sliver. This embodiment of the invention reliably ensures that at the start of the generating process, the free end of the sliver is arranged in the vortex chamber in a desired manner for connection with the free thread end.

[0015] The drafting device for conveying the sliver toward the inlet of the vortex chamber of the air-jet spinning unit has an output roller pair that can be driven independently of the at least one other drafting roller pair and / or belt roller pair. The drafting device is characterized by a control unit for implementing the method described above, according to the invention or a further improvement, of operating the drafting device after a spinning interruption. The control unit can be directly arranged at the spinning station, or, according to an advantageous improvement of the invention, integrated into a central control unit for more than one spinning station or a central control unit of the air-jet spinning machine. The central control unit is preferably a mobile or stationary device located outside the spinning station and / or the air-jet spinning machine. Particularly preferably, the control unit or control unit is adapted to variably adjust the carding speed and / or holding speed to achieve optimal matching with the fiber. Attached Figure Description

[0016] An embodiment of the present invention will now be described with reference to the accompanying drawings. Wherein:

[0017] Figure 1 This is a front view of an air-jet spinning machine including a workstation, which has its own yarn pickup device and yarn pretreatment device for supplying its air-jet spinning unit.

[0018] Figure 2 This is a schematic cross-sectional view of an air-jet spinning device during the head-forming operation. Detailed Implementation

[0019] Figure 1 A schematic front view of a textile machine (here, an air-jet spinning machine 1) for manufacturing take-up bobbins, commonly referred to as cross-shaped bobbins 9. This type of textile machine 1 has several spinning stations 2 between frames 13a and 13b on the machine end side. Each of the spinning stations 2 is equipped with a spinning jar 3, which is equipped with a reserve of reference material, such as sliver 25.

[0020] Spinning station 2 also includes a drafting device 4, an air-jet spinning device 5, a take-up device 6, a yarn clearer 7, and a yarn traverse device 8, which are used to wind the yarn 36 spun or manufactured in the air-jet spinning device 5 with sliver 25 into take-up bobbins 9 in cross layers. The so-called cross-shaped bobbins 9 generated during the spinning process are, as is common, held in bobbin frames (not shown) and rotated by bobbin drivers (also not shown).

[0021] Each of the spinning stations 2 is also equipped with a yarn pick-up device 39, which is used to pick up the yarn ends 37 of the manufactured yarn 36 wound onto the cross yarn spool 9 after a spinning interruption and move them to the so-called yarn pretreatment device 40 located in the area of ​​the lead-out device 6.

[0022] Figure 2 A side view and a larger scale show an air-jet spinning apparatus 5, suitable for implementing the method according to a preferred embodiment, during the head-growing operation.

[0023] As shown in the figure, upstream of the air-jet spinning device 5 (shown in cross-section), there is a drafting device 4 for drafting the sliver 25. A take-up device 6, reversibly driven by a single motor, is installed downstream of the air-jet spinning device 5 along the sliver conveying direction R, for conveying the manufactured yarn 36 toward the take-up bobbin 9 and in the opposite direction.

[0024] Within the area of ​​the yarn lead-out device 6, there is also a yarn pretreatment device 40 (not shown in detail here), which pretreatments the yarn ends 37 of the finished yarn 36 retrieved by the yarn pickup device 39 for subsequent yarn start-up operations.

[0025] like Figure 2 As shown, the air-jet spinning device 5 mainly consists of two-part outer shells 14 and 15, an expansion shell 16, a nozzle assembly 17, a sliver guide 18, and a hollow spinning cone 19.

[0026] The expansion shell 16 forms a front annular space 20 in combination with the front shell component 14 of the outer shell. The front annular space is connected to the overpressure source 22 via a pneumatic line 21 and is connected to the expansion space 28 located in the rear shell component 15 of the outer shell.

[0027] The expansion space 28 is indirectly connected to the ambient atmosphere through the exhaust duct 29, while the annular space 20 is pneumatically connected to at least one blower nozzle 23 located in the nozzle assembly 17.

[0028] The blower nozzle 23 communicates with the vortex chamber 33 in the region before the inlet 35 of the spinning cone 19 and faces the head 24 of the spinning cone 19, thereby generating a rotating airflow at the head. The spinning cone 19 is preferably made of a material with high wear resistance, such as a process ceramic material.

[0029] To control the input of pressurized air, the pneumatic line 21 is equipped with a valve 32, which is preferably operated by a control unit 38 of the spinning station, which is connected to the valve through a corresponding control line.

[0030] During a typical spinning operation (not shown), the sliver 25 stored in the spinning jar 3 first passes through the drafting device 4 on its path to the cross-shaped yarn spool 9, where it is highly drafted. Subsequently, the drafted sliver 25 is fed into the region of the input opening 27 of the air-jet spinning device 5 via the output roller pair 26 of the drafting device 4, and is drawn into the vortex chamber 33 of the air-jet spinning device 5 under the influence of a negative pressure flow. Inside the air-jet spinning device 5, the drafted sliver 25 passes through the sliver guide 18 and the nozzle assembly 17 to the inlet 35 of the hollow spinning cone 19, and is drawn into the spinning cone 19 by the yarn 36 formed within it. The sliver 25 is affected by a rotating fluid in the region of the head 24 of the spinning cone 19, which is generated by the airflow exiting from the nozzle assembly 17.

[0031] In order to guide the airflow caused by the overpressure source 22 to the nozzle assembly 17 in a defined manner, valve 32 is opened. In order to allow the airflow flowing in through the nozzle assembly 17 to flow out to the ambient atmosphere or the machine's own suction device through the exhaust channel 29 during the spinning process, valve 34, which is connected to the control unit 38 via the corresponding control line, is opened.

[0032] During the spinning process, the continuous movement of the sliver 25 along the sliver transport direction R causes the sliver 25 to be continuously drawn into the hollow spinning cone 19, wherein the edge fibers spirally wrap around the core fibers of the sliver 25. The yarn 36 thus produced is drawn out from the air-jet spinning device 5 by means of the yarn drawing device 6 and then wound into a cross-shaped yarn bobbin 9.

[0033] If spinning is interrupted during the spinning process, for example, due to breakage of the sliver 25 or controlled cutting of the spun yarn 36 by the yarn clearer 7, a start-up operation must be performed before restarting the spinning process.

[0034] It is known that in order to carry out the yarn production operation, on the one hand, a drafted sliver 25 is required, and on the other hand, a pre-manufactured yarn 36 is required to be wound onto the cross-shaped yarn cylinder 9.

[0035] After spinning is interrupted, the yarn end 37 of the completed yarn 36 is retrieved from the cross-shaped yarn spool 9 by the yarn pickup device 39 of the relevant spinning station 2, and then sent to the yarn pretreatment device 40 located downstream of the air-jet spinning device 5 along the sliver conveying direction R. Here, the yarn end 37 is untwisted and loose fibers are removed as much as possible. The yarn end is then fed into the vortex chamber 33 for starting and positioning.

[0036] In order to pre-treat the sliver 25, during the feeding of the thread end 37 back to the vortex chamber 33, the drafting device 4 is operated in combing mode by the control unit, wherein the first drafting roller pair 42, the second drafting roller pair 43 and the belt roller pair 41 are stationary, while the output roller pair 26 runs at combing speed, and in this case, the free end of the sliver 25 is optimally pre-treated for the growing process.

[0037] Appendix Label Table

[0038]

Claims

1. A method of operating a drafting device (4) having an output roller pair (26) and at least another drafting roller pair and / or belt roller pair (41), wherein a sliver (25) for making yarn (36) is fed into the vortex chamber (33) of the air-jet spinning device (5) at the spinning station (2) of an air-jet spinning machine (1) by means of the drafting device, wherein, The output roller pair (26) can be driven independently of the at least one other drawing roller pair and / or belt roller pair (41). Its features are, After spinning is interrupted, the output roller pair (26) is driven at a set combing speed to comb the sliver end. This combing process adjusts the sliver end to provide optimal pretreatment for the sliver end during the sliver tip formation process in the vortex chamber. At least one other drafting roller pair and / or belt roller pair (41) located upstream of the output roller pair (26) along the sliver conveying direction (R) is stopped or operated at a holding speed corresponding to the combing speed, the holding speed being a maximum of 10% of the combing speed. After combing, the stretching device (4) is stopped, and then the stretching device is started to grow the head.

2. The method according to claim 1, characterized in that, When the drafting device (4) is activated during the head-growing process, the output roller pair (26) is driven in a manner that precedes the at least one other drafting roller pair and / or belt roller pair (41).

3. A drafting device for conveying sliver (25) toward the inlet (35) of the vortex chamber (33) of an air-jet spinning device (5), wherein, The drafting device (4) has an output roller pair (26) that can be driven independently of at least another drafting roller pair and / or belt roller pair (41). Its features Control unit (38) for implementing the method of operating the drafting device (4) after a spinning interruption according to claim 1 or 2.

4. The drawing device according to claim 3, characterized in that, The control unit (38) is integrated into the central control unit of the jet spinning machine (1).

5. The drawing device according to claim 3 or 4, characterized in that, The control unit (38) is configured to variably adjust the combing speed and / or the holding speed.

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