DE102013003286A1 - Method for operating textile machine used for manufacturing cross wound bobbin, involves setting pitch angle of threads such that ratio of pitch angle in alternate directions over entire bobbin remains constant - Google Patents

Abstract

The method involves providing a cross-winding device (10) for traversing a thread (16) of cross wound bobbin (5) by alternately moving the thread in opposite directions. An electromechanical drive device (14) is arranged for rotating the cross wound bobbin. The pitch angle of the threads in laying direction differs from each other and absolute values of the pitch angles are varied according to the diameter of bobbin such that the ratio of pitch angle in alternate directions over the entire bobbin remains constant.

Description

The invention relates to a method for operating a workstation of a cross-wound textile machine with a creel for holding a rotatable cheese, a thread laying device for traversing a trailing yarn on the cheese, that is, the alternate laying in opposite directions and a drive for rotating the cheese, wherein the pitch angle in one laying direction differs from the pitch angle in the other laying direction, and the absolute values of the pitch angles vary depending on the diameter.

Textile machines producing cross-wound bobbins have been known for a long time and generally consist of a large number of similar workstations arranged in series next to one another. On the jobs, for example, a winder spinning cops, which have relatively little thread material, rewound to large-volume cheeses. About such winding units but also have other textile machines, such as rotor spinning, friction spinning or air spinning machines, which then allow in conjunction with spinning stations the winding of cheeses. Thread supplier is then instead of a feed bobbin the corresponding spinning station.

The cheese is an intermediate product which is processed in the further production processes of textile production. Therefore, not only to the yarn, but also to the structure of the cheese are high quality requirements. The quality of the cross-wound bobbin takes on a key function in the textile production process, because the size of the possible thread take-off speed is nowadays often the performance-limiting factor in textile finishing, for example in the case of air-jet or series shed weaving machines.

The run-off behavior and thus the possible withdrawal speed of the thread has become a decisive quality criterion, the run-off behavior of the cross or supply bobbin being characterized by the process-related up and down migration of the thread on the cross-wound bobbin during overhead take-off. This leads to fluctuations in the take-off speed and the thread tension, whereby the run-off behavior can be characterized. In the course of the increase in performance, the unwinding must meet ever higher requirements.

In order to produce a cross-wound bobbin, also referred to as a package, in the winding process, the package must firstly be set in rotation and, secondly, the yarn running onto the package must be laid along the package bobbin axis. By relatively fast laying of the thread then a Kreuzbewicklung can be achieved.

Usually, this means that the cheese of a Spulmaschinenarbeitsstelle is driven at the periphery by a so-called coil drive roller. The bobbin drive roller may be formed, for example, as a yarn guide drum and leads the yarn during the winding process before emergence on the cross-wound bobbin back and forth. Alternatively, the thread is changed by means of a separate thread guide in front of the cross-wound bobbin, wherein the bobbin drive roller is then not provided with Fadenführungsnuten.

As a result, during winding, each subsequent layer traverses the already wound threads and results in a crossing of the threads, which gives the cheese its name. Due to the laying pattern, the cross-wound bobbin has firm and stable edges and does not have lateral discs on the front sides. Significant parameters here are the turns ratio, the crossing angle and the pitch angle.

The turns ratio is defined by the number of coil revolutions per double stroke of the traversing device.

In this context, the crossing angle is understood to be the angle which results from the crossed turns and thus corresponds to the sum of the helix angles. The thread is laid over the stroke, so the simple traverse path length. At the end of the stroke, the movement is reversed, so that the thread is now wound at the opposite pitch angle.

For packages of staple fiber yarns crossing angles of 30 ° to 45 ° are common, depending on the intended use, manufacturing process and raw material. A small crossing angle results in a high density and thus a higher weight of the cross-wound bobbin.

However, there is the danger that at high take-off speeds in the further processing process, so-called loops occur because juxtaposed layers are entrained. If, on the other hand, the thread is wound onto the cross-wound bobbin by means of a large crossing winding, the result is lower density and weight. This is particularly advantageous for cheeses that are dyed.

The pitch angle, on the other hand, indicates the angle of a turn with respect to a perpendicular of the coil axis. For better distinction in this document, the pitch angle of the Fuß- Head side labeled with α, while the pitch angle is called from the top to the foot side with β.

The thread is usually deducted in the subsequent processing processes "overhead". This so-called overhead take-off occurs when the cross-wound bobbin is attached to a fixed mandrel and the thread is pulled off in the axial direction. Due to the centrifugal force, which acts radially outward at each point of the detached thread, depending on the withdrawal speed between the thread release point on the cross-wound bobbin and the withdrawal eye, a so-called thread balloon is produced. Since the peripheral speed of the thread balloon is dependent on its radius, the angular velocity is usually used for the characterization. The swinging in a balloon thread has an influence on the applied force with which the thread must be removed from the supply reel.

There are two types of thread balloon: the one-piece thread balloon consists of a large belly and the multi-part thread balloon of several small bellies. The first form usually occurs when pulling the thread from the full cheese when many thread layers are still present on the cheese and the cheese diameter is large. With increasing consumption, the cheese diameter is reduced and the yarn balloon jumps after the unwinding of a certain length of thread from the cross-wound bobbin suddenly in the second form, but usually falls back shortly thereafter back into the first. This process is sometimes repeated a few times, until finally the second balloon shape is retained.

Due to the air resistance, each thread balloon undergoes a twist, causing it to form spirally. The air resistance is proportional to the speed and grows with its square. Since the circumferential or angular velocity of the one-piece yarn balloon is greater than the multipart, the air resistance acts accordingly stronger. In the yarn balloon results in a combination of centrifugal force and twisting. The centrifugal force is highest at the location of the largest diameter and thus determines the yarn tension ratios in the yarn balloon.

In the multi-part thread balloon, the centrifugal force due to the distortion caused by each tummy of the thread balloon in a different direction. This has the consequence that the diameter of the thread balloon remains limited. The twist remains relatively low, because it is divided into several monofilament balloons. This means that the thread balloon already reaches its full diameter at one point, where it has experienced little twisting. At this point, the centrifugal force acts in a direction that only slightly passes the point at which the thread separates from the cheese. This results in a free lifting of the thread from the cross-wound bobbin. The inherent to the yarn balloon momentum causes the multi-part thread balloon this favorable release of the thread from the coil.

The one-piece thread balloon, however, has only one point with a large diameter. Most of the centrifugal force acts in one direction, increasing the diameter of the thread ballon. This, in turn, causes greater distortion, with the centrifugal force acting opposite to the direction of separation of the thread from the cross-wound bobbin. As a result, the thread rubs when pulling on the cheese body, which on the one hand, the thread tension increases significantly and on the other hand, the thread layers are loosened on the cheese. Such loosened thread layers then solve contiguous as slip turns of the cheese and affect the further processing. These sporadically occurring thread tensile force peaks of the thread balloons limit the yarn withdrawal speed.

By the US 2,764,368 discloses a method of producing conical cheeses whose lead angle of one laying direction differs from the pitch angle of the other laying direction. The pitch angle of the thread when winding from the narrower cheeses side, the so-called head side, to the wider side, the foot side, smaller than when winding from the foot to the head side. Depending on whether the separation point of the thread on the cheese from the top to the foot or the foot to the head wanders, more or less thread is removed. Corresponds to the direction of movement of the separation point of the former variant, more yarn is unwound than is the case in the second variant.

According to the generic EP 1 358 120 B1 It is known, in addition to the different pitch angles according to the US 2,764,368 to vary the ratio of pitch angles of the different laying directions over the spool travel. As a result, tensile forces occurring during unwinding should be reduced in terms of amount or the range in which they occur should be restricted. An early formation of a stationary single balloon is to be achieved as well as the transition region from the single balloon to the multi-balloon, in which it comes to a rollover be limited. In addition, the diameter of the cheese, on which it comes for the first time to change from a single balloon to a multi-balloon, to be moved to larger diameters. This should reduce thread breaks and enable a higher take-off speed.

A disadvantage of the method according to the prior art proves that thread tensile forces still occur which are only short-term, but significantly above the average yarn tension. These fluctuations and the associated yarn tension peaks are still the limiting factor in the processing textile processes, on the basis of which there is a further need for optimization.

Based on the aforementioned prior art, the present invention seeks to propose a method that further optimizes the flow behavior of a cross-wound bobbin in the further processing processes.

This object is achieved by the characterizing features of claim 1.

Advantageous embodiments of the invention are the subject of the dependent claims.

According to claim 1 it is provided that the ratio of the pitch angle in the changing installation directions over the entire coil travel remains constant.

The desired improvement in runnability is achieved by varying the absolute pitch and crossing angles in both installation directions, but maintaining a constant ratio of pitch angles throughout the coil travel. This produces a cross-wound bobbin characterized by a stable and uniform structure. Thanks to the invention, the flow behavior of the thread is positively influenced by the cheese, the formation of the thread balloon evened and occurring at short tensional force peaks are further minimized, so that the thread withdrawal speed can be increased again. Improved process characteristics also reduce downtime by reducing thread breakage during further processing. The invention improves productivity and makes it possible to increase the efficiency of the subsequent textile processes.

In an advantageous embodiment, the change in the pitch angle, as set forth in claim 2, caused by changing the traversing speed. Since the pitch angle is the product of delivery speed and traversing speed, the traverse speed is varied so as not to decrease the productivity of the winder.

The invention will be explained in more detail with reference to an embodiment shown in the drawings.

It shows:

1 1 schematically shows a winding unit of a textile machine producing cross-wound bobbins, with a cross-wound bobbin driven on its circumference by a single motor, and a separate, single-motor-driven thread guide;

2 in front view a winding unit of a cross-wound producing textile machine,

3 a schematic, according to the invention wound cross-wound bobbin.

In 1 is a side view schematically a winding unit 2 a textile machine producing cross-wound bobbins 1 , In the present case of a so-called cross-winding machine shown.

Such spoolers 1 have, as is known, between their end frames, not shown, in each case a plurality of such winding units 2 on.

On these winding units 2 are, as also known and therefore not explained in detail, produced on an upstream ring spinning machine spinning cops 3 to large-volume cheeses 5 rewound, after its completion by means of a service unit, not shown, for example, a cheese changer, on a machine-length cheese package transport device 7 passed and transported to a machine end side arranged Spulenverladestation or the like.

Such spoolers 1 often also have a logistics facility in the form of a bobbin and tube transport system 6 ,

In this coil and tube transport system 6 the transport plates are running 11 , the spinning cops 3 or carry empty tubes to.

From the bobbin and tube transport system 6 are in 1 only the Kopszuführstrecke 24 , the reversibly drivable storage section 25 , one of the winding units 2 leading transverse transport routes 26 as well as the sleeve return path 27 shown.

The individual winding units 2 have, as known and therefore only indicated, each of various facilities that ensure the proper operation of such jobs.

One of these devices is for example the one with the reference number 4 characterized winding device, the one about a pivot axis 12 movably mounted creel 8th having.

In the present case lies the cheese 5 during the winding process with its surface 31 on a variable-speed drive device, the so-called drive roller 9 , on and is taken by this over frictional.

In an alternative embodiment, the drive of the cross-wound bobbin but also via a drive device, which directly on the creel 8th arranged or in the creel 8th is integrated.

The traversing of the thread 16 during the winding process is done by a thread laying device 10 ,

Such in the 1 only schematically indicated thread laying device 10 has a finger-trained yarn guide 13 that, by an electromechanical drive 14 charged as in 2 indicated the thread 16 between the two end faces 32 the cheese 5 traversed.

How out 2 further apparent, the drive has 14 a motor shaft 33 on, on the finger-trained yarn guide 13 is arranged rotationally fixed.

The winding unit 2 furthermore has a thread cleaner 22 that has a signal line 29 to the winding station computer 28 is connected as well as one in the area of the thread cleaner 22 arranged thread cutting device 23 over a line 30 from the winding station computer 28 is controllable.

In an advantageous embodiment, a yarn tension sensor is also provided 20 provided, via a signal line 21 with the winding station computer 28 connected is.

As in 2 is indicated during the regular winding operation of one on a transport plate 11 arranged in an unwinding position in the region of the transverse transport path 26 positioned spinning cop 3 a thread 16 unwound and on a large volume cheese 5 wound during the winding process rotatably between the bearing arms of a coil frame 8th is held.

The cheese 5 lies with its surface 31 on a drive roller 9 on.

The drive roller 9 is by an electromagnetic drive 34 , which has a control line 19 with the winding station computer 28 is connected, defined drivable and takes the cheese with frictional.

The string 16 crosses on his way to the cheese 5 at least the thread cleaner 22 as well as the thread cutting device 23 ,

The running thread 16 that by the thread cleaner 22 monitored for thread error, generated in the thread cleaner 22 Among other things, a dynamic yarn path signal, which via the signal line 29 on the winding station computer 28 is transmitted.

3 shows a schematic and inventively wound cheese 5 , On an empty tube 15 becomes the thread 16 wound. Every thread layer 16 It is wound on changing sizes, with the smallest size on the empty tube 15 , the biggest one on the full cheese 5 results. The pitch angle β 35 is from the head side 36 to the foot side 37 the cheese 5 smaller than the pitch angle α 38 from the foot side 37 to the head side 36 , This will be in the laying direction of the head 36 to the foot side 37 more turns of the thread 16 on the empty tube 15 applied as in the opposite direction of installation. The slope angle 35 . 38 Change in the course of the coil travel by the traversing speed is changed. That means the faster the thread 16 on the cheese 5 is changed, the greater the pitch angle 35 . 38 , The ratio of the different pitch angles 35 whereas it is maintained throughout the trip.

With the method according to the invention, for example, a cheese 5 are prepared, while maintaining a constant pitch angle ratio both pitch angle α 38 and β 35 increase over the coil travel. In this way you get a cheese 5 with a high density of the spool core and a decreasing density of the cheese 5 outward. Since the outer thread layers do not press so much on the inner thread layers, so creates a compact cross-wound bobbin 5 whose structure has a positive effect on the flow behavior.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US Pat. No. 2,764,368 [0018, 0019]
• EP 1358120 B1 [0019]

Claims (2)

A method for operating a workstation of a cross-wound textile machine with a creel for holding a rotatable cheese, a thread laying device for traversing a trailing yarn on the cross-wound bobbin, that is, the alternate laying in opposite directions and a drive for rotating the cross-wound bobbin, wherein the pitch angle in the a laying direction is different from the pitch angle in the other laying direction and wherein the absolute values of the pitch angles vary depending on the diameter, characterized in that the ratio of the pitch angles in the changing laying directions remains constant over the entire spool travel. A method according to claim 1, characterized in that the change of the pitch angle is effected by changing the traversing speed.

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