EP0055849B1 - Method and device for winding yarn - Google Patents

Description

The invention relates to a method for winding yarns or tapes continuously fed at a constant speed to a winding device in a gradual precision winding, and to a winding device for carrying out the method.

Rovings, spun yarns and filament yarns are usually produced at a constant delivery speed; this means that the yarns must also be wound at a constant speed. There are systems such as a spindle with ring and ring traveler or flyer, in which the winding also involves a rotation, but also pure winding systems that wind up without rotation. With the pure winding systems, two fundamentally different methods of coil construction are used, namely the precision winding and the wild winding.

With precision winding, the bobbin speed and the number of double strokes of the traversing thread guide form a fixed ratio, the so-called bobbin ratio. Depending on the level of this winding ratio, bobbins in parallel winding, in which the traversing thread guide shifts by the thread size by one turn of the bobbin, or bobbins with more or less strongly crossed layers of yarn can be produced. The yarn can be tailored according to individual requirements, e.g. Layer to layer wound, but you can also distribute the reversal points on the end faces of the coil as evenly as possible over the coil circumference. Precision-wound coils can therefore be optimally adapted to the special requirements of the material to be wound or its use.

In the case of the wild winding, the circumference of the coil is driven by a drive roller at a constant circumferential speed. The traversing movement is coupled with the rotation of the drive roller and takes place at a constant frequency. This gives a thread crossing that is dependent only on the ratio of these two sizes and is therefore constant over the entire package build.

As a result of the bobbin drive taking place at a constant peripheral speed, the wild winding is ideal for winding yarns that are supplied at a constant speed. However, the winding ratio is constantly changing. In the case of integer values for the bobbin ratio - this is usually the case several times over the bobbin build-up - the yarn is laid on top of one another in several layers in the same turn. This process is also called image or mirror winding. Windings deposited in this way are relatively loose and, particularly with smooth filament yarns, tend to form an unstable bobbin. This can lead to great difficulties when processing the bobbin due to excessive thread tensile forces, falling or shooting layers, loop formation, etc., which in the end results in unnecessarily high thread break counts. Attempts have been made to disturb the uniformity of the coil drive, e.g. to avoid such image windings by controlled, brief changes in the slip between the drive roller and the spool, or also by a disturbance in the frequency of the oscillating movement. Especially at high winding speeds, the technical effort for this is quite considerable and the success of such measures is not always fully guaranteed.

In DE-OS 21 65 045 e.g. describes a winding process and a cross winding machine for wild winding, in which the winding ratio is controlled within non-integer ratios. You can avoid the occurrence of image windings, but you cannot achieve the many possibilities of precision winding.

DE-OS 29 14 924 describes a winding device for wild winding, in which the slip of the asynchronous motor driving the traversing device is changed in the vicinity of integral winding ratios in order to avoid image winding. Even with this device, the advantages of precision winding cannot be achieved.

A disadvantage of the precision winding is that the winding speed is dependent on the respective winding diameter at a constant spool speed. The drive speed of the bobbin, e.g. regulated depending on the coil diameter. Given the constant speed at which the yarn is delivered to the winding unit, this relatively simple type of control is too imprecise. It is therefore customary to continuously record the thread tension before winding and thus regulate the bobbin speed. GB-P 999.185 also describes an arrangement in which the peripheral speed of the coil is detected and kept constant by regulating the coil drive.

The technical effort for these control systems is considerable. With the high winding speeds and spool weights as they are e.g. are common in chemical fiber production, the inertia of these control systems is too high to ensure the necessary uniformity of thread tension. The strain on the yarn due to the continuous recording of the thread tension is no longer acceptable for some areas of application.

Another disadvantage of the precision winding is that the crossing angle of the yarn becomes smaller as the bobbin diameter increases. With a large ratio of the diameter of the full and empty coil, this can lead to the Crossing on the bobbin tube becomes too steep and a proper bobbin build is therefore no longer possible, while with a full bobbin the crossing becomes so flat that difficulties arise during processing.

In chemical fibers / textile industry from June 1980, a winder is described on page 520, in which the bobbin is built up in a precision winding, but the bobbin ratio is changed at predeterminable bobbin diameters by a sudden increase in the traversing frequency. A disadvantage of this design is that both the speed of the spool and the traversing drive must be controlled separately.

DE-AS 19 13 451 describes a precision cross winder in which the coil is driven on its circumference. The spool speed, which changes depending on the spool diameter, is recorded and used to control the traversing drive. A predetermined, constant winding ratio is maintained.

A similar arrangement is also described in DE-OS 20 61 594. The disadvantages of the changing crossing angle with respect to the full and empty coil are not eliminated. In addition, the winding speed itself changes with the crossing angle at a constant circumferential speed of the coil. This inevitably leads to lower thread tensile forces when the bobbin becomes full; this means that the thread elongation at the beginning of the winding must be chosen to be very high. With the usual diameter ratios of full and empty bobbins of around 5: 1, this is practically only possible with elastomer yarns.

DE-AS 26 49 780 describes a winding machine for textile yarns in which the bobbin is driven on its circumference by means of a speed-controlled drive roller and the reverse thread shaft in which the traversing thread guide is moved is also speed-controlled. Both speeds are controlled by electronic control circuits and computers, which include take into account the mathematical relationships between winding speed, peripheral speed of the bobbin or drive roller and thread laying speed, regulated in such a way that the difference between thread speed and winding speed can be specified. With this device, the production of precision bobbins with constant feed speed and constant thread tension during winding is possible. In this case, preprogrammed jumps in the winding ratio can be carried out on the computer in order to avoid awkward areas of the crossing angles when the bobbin is full and empty. The technical effort for these computer-controlled speeds of the drive roller and the reverse thread shaft is correspondingly high. An economically sensible application 5 of the device described is thus significantly burdened.

A method and a winding device according to the first part of claims 1 and 5 are known from Japanese laid-open specification 65 628. In the winding device, the circumference of the bobbin is driven by a drive roller. A detector is connected to the drive roller drive motor, which detects the loading torque of the drive motor and controls the coil drive motor via a control unit. Another detector records the speed of the traversing thread guide and feeds a corresponding output signal to a control circuit, which also records the output signal of the bobbin detector, which is dependent on the speed of the bobbin. The control circuit is programmed in the sense of a step-by-step precision winding and gives a control signal to the drive motor for the traversing thread guide when the winding ratio changes.

The limits for the change in the winding ratio are determined such that a maximum oscillation frequency predetermined by the mechanical load-bearing capacity of the oscillation drive is not exceeded and the minimum oscillation frequency determined by the minimum crossing angle required for sufficient coil cohesion is not undershot.

In the version with constant bobbin circumferential speed, i.e. without regulating the bobbin speed as a function of the thread tension during winding, the thread tension is continuously measured and the switchover time from a bobbin ratio to the next fixed bobbin ratio selected so that the bobbin tension ranges from 0.05 to 0.5 g / who doesn't leave. The necessary continuous measurement of the thread tension affects the yarn quality particularly at high winding speeds. In addition, considerable technical effort is required for the exact determination of the very low thread tension, which is customary when switching. In spite of this, if the thread is fed in at a positive, constant speed, the measures described here can only have an insignificant influence on the maximally occurring thread tensile forces and thus also their adverse influence on the quality of the yarn and the bobbin.

The invention is therefore based on the object of specifying a method for winding yarns or tapes supplied at a constant speed in a gradual precision winding, which has the disadvantages of the known methods, but in particular too large differences in the winding speed and their adverse effects on the quality of the yarns and of the coil structure, on simple Way avoids.

This object is achieved by a method according to claim 1, for the implementation of which a winding device according to claims 4 and 5 is suitable.

This solution combines the advantage of the wild winding with regard to the technically very simple winding by driving the coil on its circumference at a constant circumferential speed with the possible variations of the precision winding for an optimal coil construction in an economical manner.

According to FIGS. 1 and 2, the bobbin (2) is driven at its circumference by means of a drive roller (3) at constant circumferential speed in order to wind up yarn (1) fed at a constant speed. The speed of the coil changes depending on the coil diameter reached. To build up the bobbin, the yarn to be wound is laid in the axial direction using a traversing thread guide (4) according to certain laws. The drive of the traversing thread guide can e.g. by means of an eccentric, cam, reversing thread shaft, grooved drum or a threaded spindle that changes the direction of rotation.

For a precision winding, the movement of the traversing thread guide must be controlled so that a complete back and forth movement always corresponds to a constant number of revolutions of the bobbin. The coil speed decreases in accordance with the growing coil diameter. Therefore, the drive of the traversing thread guide must be coupled with the rotation of the bobbin. This is expediently done using an electrical or electronic control system. There are many options available for this today.

The basic structure of such a control system is shown in Fig.2. The speed of the pulse (2) is recorded analogously by means of a tachometer (5) and entered as a setpoint in the controller (7.). Likewise, the speed of the drive motor (10) is recorded analogously by means of a tachometer (6) and entered as an actual value in the controller (7). The setpoint and actual value are compared with one another in the controller and used to regulate the supply of the traversing thread guide drive (10).

For example, a DC motor can be used to drive the traversing thread guide, the controller changing the motor speed via the supply voltage in the desired sense. However, a synchronous or asynchronous motor with regulation of the frequency of the supply voltage can also be used.

Especially at low traversing speeds, as e.g. in parallel winding, it is advantageous to detect the rotation of the bobbin via a pulse generator and thus to control a stepper motor which drives the thread guide.

By a step change in the coil ratio during the coil build-up in several phases, the crossing can be kept within limits that are favorable for the coil build-up. This change in the winding ratio must be such that integer winding ratios are run through faster than a winding game lasts. When jumping from one winding phase with constant winding ratio to the next, the crossing angle is increased. According to the relationships shown in FIG. 3, the wind-up speed also increases as a result. By appropriately grading these jumps, it can be achieved that this change in the winding speed is kept so low that it has no adverse effect on the yarn properties or on the package build. How this gradation is optimized is shown in the later examples.

The still portable change in the wind-up speed depends to a large extent on the application in question. For example, when winding the yarn on a twisting machine, increasing the winding speed from one winding phase to the next has no influence on the bobbin build-up, since the thread tension practically does not change. The higher wind speed will only reduce the yarn twist. In this case, a change in the wind speed of less than 3% would still have no adverse effects on the quality. In contrast, in a spinning draw frame for high-strength, low-stretch yarns, increasing the wind speed will affect the thread tension. If this is too high, this can be noticeable both as a fluctuation in the elongation in the yarn and as an unfavorable influence on the even package build. However, if the change in the wind-up speed is less than 0.3%, this is in the range of other, unavoidable influences and experience has shown that it is of no importance.

With small winding diameters, a change in the thread tension affects the bobbin build less than with the full bobbin. It is therefore advantageous to let the change in the wind-up speed decrease in the last winding phases.

The amount of the integer part of the winding ratio influences the crossing angle in connection with the coil diameter. The fractional part of the winding ratio is mainly influenced by the displacement of the stroke reversal points at the beginning of the spool. For a good spool build-up, it is essential that the sum of these stroke reversal points is distributed as evenly as possible at the start of the spool. At the same time, however, their order should also be as symmetrical as possible and avoid a temporal focus.

`This is achieved particularly well if the broken part of the winding ratio e.g. is 2/5 or 3/5 or 2/7, 3/7, 4/7 or 5/7, since then the subsequent reversal point acc. Fig.4 lies approximately on the opposite side. With 1/5 and 4/5 or 1/7 and 6/7, the reversal point moves along the circumference, but is also evenly distributed. In addition, the 6th or 8th reversal point must be prevented from falling on the first reversal point. This is achieved by the fact that the set winding ratio in the fractional part deviates slightly from the values mentioned above.

In contrast to a form-fitting translation, electronic translation does not necessarily work with exactly constant translation ratios. The deviations can be kept very small, but must be taken into account in the considerations above.

If e.g. the initial winding ratio is 10 and the possible deviation in the gear ratio is 0.1%, a deviation of the winding ratio by the absolute value 0.01 must be expected. This means that the above-mentioned broken parts of the winding ratio must be changed by more than 0.01 in order to ensure that reversal points do not return to the same place after just a few turns. Another condition is of course that in this area too there is no other simple divisor.

It is advantageous to control the signal transmitter (8) for the changeover of the winding ratio via the speed of the drive of the traversing thread guide and to trigger the signal each time an adjustable minimum speed thereof is reached. The signal acts on a tap changer (9) and thus changes the actual value entered into the controller.

There are a number of areas of application in which the process can be carried out economically on winding units with individual control. As a rule, however, the effort required for textile machines with a large number of jobs will be too high. On the other hand, however, the desire for an optimal bobbin construction is particularly great due to the sometimes enormously increased processing speeds. If you change the full bobbins of a machine at the same time, all running bobbins have approximately the same winding diameter. In this case, it is possible to provide the entire machine with only one control device for producing precision coils, which is controlled by a master coil. However, in order to be able to compensate for extreme differences in the coil hardness and thus also in the coil diameter, it is better to use the speed averaged from several coils to regulate the traversing drive. This can also be used to counter the risk that the control will fail as a result of a thread break on the master bobbin.

• Fig. 1 zeigt den Querschnitt durch ein Spulaggregat. Das Garn (1) wird von einer Liefereinrichtung der Spule (2), die mittels der Treibwalze (3) an ihrem Umfang mit konstanter Geschwindigkeit angetrieben wird, zugeführt und vom Changierfadenführer (4) nach vorgegebenen Gesetzen verlegt.
• Fig. 2 zeigt das Blockschaltbild für die Regelung des Changierantriebs. Der Analogwert der Drehzahl der Spule (2) wird von einem Tachometer (5) ermittelt und als Sollwert dem Regler (7) zugeführt. Die Drehzahl des Antriebsmotors für den Changierfadenführer (10) wird vom Tachometer (6) analog erfaßt und als Istwert dem Regler eingegeben. Beim Erreichen einer vorgegebenen Mindestdrehzahl des Motors (10) schaltet der Signalgeber (8) den Stufenschalter (9) und Ändert damit den dem Regler einzugebenden Istwert.
• Fig. 3 stellt schematisch die Zusammenhänge zwischen Umfangsgeschwindigkeit der Spule, Aufwindegeschwindigkeit des Garns, Changiergeschwindigkeit und Verkreuzungswinkel dar.
• Fig. 4 zeigt Möglichkeiten für die Lage der Umkehrpunkte des Changierfadenführers am Umfang der Spule.
• Fig. 5 zeigt die Abhängigkeiten von Spulendrehzahl, Anzahl der Doppelhübe, Spulverhältnis und Fehler in der Aufwindegeschwindigkeit vom Spulendurchmesser anhand der Werte von Beispiel 1.

The following drawings and examples serve to explain the invention in more detail.

• Fig. 1 shows the cross section through a winding unit. The yarn (1) is fed from a delivery device to the bobbin (2), which is driven at its circumference at a constant speed by means of the drive roller (3), and laid by the traversing thread guide (4) in accordance with prescribed laws.
• Fig. 2 shows the block diagram for the control of the traversing drive. The analog value of the speed of the coil (2) is determined by a tachometer (5) and fed to the controller (7) as a setpoint. The speed of the drive motor for the traversing thread guide (10) is recorded analogously by the tachometer (6) and input to the controller as the actual value. When a predetermined minimum speed of the motor (10) is reached, the signal transmitter (8) switches the step switch (9) and thus changes the actual value to be entered into the controller.
• Fig. 3 shows schematically the relationship between the peripheral speed of the bobbin, winding speed of the yarn, traversing speed and crossing angle.
• Fig. 4 shows possibilities for the position of the reversal points of the traversing thread guide on the circumference of the bobbin.
• 5 shows the dependencies of spool speed, number of double strokes, spool ratio and errors in the winding speed on the spool diameter on the basis of the values from Example 1.

example 1

A spinning machine for synthetic filament yarns spins at a speed of 3,300 m / min and is wound onto a cross-wound bobbin driven at a constant speed by means of a drive roller. The sleeve diameter of the coil was 85 mm, the diameter of the fully wound coil was 450 mm. The winding stroke was 250 mm. The speed of the coil holder is determined by a tachometer. The traversing movement of the thread guide is generated by a reversing thread which is driven by a direct current motor, the speed of which is also determined by a tachometer. 7 revolutions of the reverse thread shaft generate a double stroke of the traversing thread guide. The crossing angle must not be less than 7 ° and the coil is built up in gradual precision winding.

The analog values of the two speeds are fed to a controller, which regulates the motor supply voltage. The analog value of the motor speed is converted in stages to change the winding ratio. The signal for switching occurs at a Engine speed of 5630 rpm, which corresponds to 804 double strokes / min. The jumps in the winding ratio were chosen so that the deviation in the wind-up speed due to the change in the crossing angle is less than 0.3%.

Claims (5)

1. Process for the progressive precision winding of yarns or tapes, which are fed into the winding device continuously at constant speed, whilst the surface speed of the receiving package also remains constant. The process is characterised in that the change in the winding ratio from one step of the precision winding to the next is so small that the resulting change in the take-up speed of the yarn or tape does not exceed 3% or preferably 0.3% of the average take-up speed.

2. Process as for Claim 1 characterised in that the sequence of transitions in the winding ratio are so chosen that the consequent changes in take-up speed at later stages of the precision winding are reduced.

3. Process as for Claims 1 and 2 characterised in that the values for winding ratio within each individual step of the precision winding are so chosen that the reversal points of the yarn traverse guide take the form of a moving 5 or 7 pointed star on the package circumference.

4. Winding device to carry out the process as for Claims 1 to 3 with a driven roller (3) to surface- drive the package (2), a yarn traverse guide (4) with a variable drive to wrap the yarn onto the package in an axial direction, a tachometer (5) to measure the speed of rotation of the package, a further tachometer (6) to measure the speed of rotation of the drive of the yarn traverse guide and a control device (7) for the drive of the yarn traverse guide. The driven roller (3) is driven with constant speed throughout the whole winding operation, characterised in that the speed ratio between the speed of rotation of the package and the speed of rotation of the drive to the yarn traverse guide is altered, by means of an electronic control device (9), in predetermined steps; and, by means of the control device (7), the speed of the traverse drive is regulated to the speed ratio momentarily required to correspond to the speed of rotation of the package.

5. Device as for Claim 4 characterised in that, at a predetermined minimum speed of rotation of the traverse drive (10), the sensor (8) switches the electronic control device (9) to the next predetermined speed ratio.

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