Title of Invention

PROCESS FOR THE OPERATION OF A TEXTILE MECHINE FOR MANUFACTURING CROSS-WOUND BOBBINS OR CHEESES.

Abstract A process for the operation of a textile machine for the manufacture of cross-wound bobbins or cheeses, which produces cross-wound bobbins in accordance with the "random winding" winding technique, in which situation, in order Jo avoid ribbon winding, the imposition pressure of the cross-wound bobbin on the thread drive drum is reduced, and the cross-wound bobbin is at the same time subjected to a braking moment, the angular velocity w of the cross-wound bobbin (4) Is constantly monitored and processed in a control device (18) in such a way characterized in that when a ribbon winding zone (BWZ) is reached, or shortly before this, the angular velocity w1, which is predetermined by the diameter d1 of the cross-wound bobbin (4), is reduced to an angular velocity w2, by the adjustment of the imposition pressure with which the cross-wound bobbin (4) is imposed on the thread guide drum (3), the said angular velocity wk, which would be featured by a cross-wound bobbin with the diameter dk driven without slippage.
Full Text -1A-
The invention pertains to a process for operation of a textile machine manufacturing cross-wound bobbins according to the winding type "wild winding", whereby to avoid image winding the support pressure of the cross-wound bobbin on the thread guiding drum is reduced and the cross-wound bobbin is simultaneously subjected to braking momentum.
When winding cross-wound bobbins or cheeses, a distinction Is basically drawn between two types of winding:
a) Precision winding and b) random winding.
With precision winding, a constant ratio is maintained throughout the entire winding process between the revolution speed of the bobbin and the speed of the thread jigging, with the result that the winding ratio throughout the entire winding process remains the same. The thread crossing angle decreases, however, as the bobbin diameter increases.
With the "precision winding" technique, no ribboning areas occur. The bobbin features a high winding density and has good unwinding properties, as a result of which high unwinding speeds can be achieved.
Because the thread crossing angle becomes smaller and smaller as the bobbin diameter grows, the stability of the yarn body is restricted. In addition to this, the decreasing thread crossing angle causes an increase in the winding density from the Inside outwards, which at the dyeing stage can lead to irregular penetration of the dye liquor.

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With random winding, there is a fixed relationship throughout the entire winding process between the bobbin surface speed and the speed of the thread jigging. As a result, the thread crossing angle is kept constant, while the winding ratio, i.e. the number of bobbin revolutions per double stroke, becomes smaller as the diameter increases.
The advantages of random winding lie in the fact that, with the "random winding" type of winding, relatively stable yarn bodies can be crea'ted, which feature very uniform density.
A disadvantageous feature of this type of winding, however, is the fact that the winding ratio decreased hyperbolically, and in certain winding ratio ranges, in which the winding ratio assumed a whole-figure value, for example, what are referred to as ribbons or reflex patterns are formed. In these so-called ribbon winding zones, the threads lie above one another in several sequential winding layers, or very close next to one another. These ribbons lead to the situation in which the cross-wound bobbin or cheese is more highly compacted in this area, with the result, for example, that irregular dyeing may occur during the dyeing process.
In addition, the risk arises that the thread areas lying on top of one another or close to one another may slip sideways onto one another, and cause mutual jamming, which has a very negative effect on the unwinding properties of a cross-wound bobbin.
In the past, therefore, numerous devices and processes have been developed which were intended to prevent the formation of ribbon winding areas of the type described.

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A process for disrupting ribbon /formation is known, for example, from EP 0 399 243 Bl, in which, in order to avoid ribbon formation, a friction drum, designed as a slotted drum, is provided for, which, starting from a basic speed of rotation, is braked and accelerated again at brief intervals by means of the drive motor, in such a way that slippage occurs both during the acceleration as well as during braking.
A ribbon disruption process is also known
1
Al)in which the speed of rotation of a thread guide
drum and the revolution speed of a cross-wound bobbin /
are assessed and the measurement results evaluated in a
computer in such a way that it can be determined when,
during the winding process, a winding ratio section is
being run through which might cause the formation of
ribbons. In these so-called ribbon winding zones, the
cross-wound bobbin is then braked by the bobbin brake in
relation to the thread guide drum in such a way that
slippage occurs between them. Once the ribbon winding
zone has been passed through, the bobbin brake is
released again, with the result that the cross-wound
bobbin is then again driven free of slippage.
In this known process, a defined reduction in the revolution speed of the cross-wound bobbin is not provided for in the ribbon winding zone, nor is it possible with the known device.
In addition to this, proposals have also been made for ribbon disruption processes in which the imposition pressure of the cross-wound bobbin on the thread guide drum is varied.
From DE 33 24 889 Al, for example, a ribbon disruption process is known in which the cross-wound bobbin held in

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the creel is continuously raised at differing lifting heights, such that the contact between the cross-wound bobbin and the thread guide drum is constantly changing in respect of temporal duration and contact pressure. In addition to this, the drive unit of the thread guide drum is switched on and off in a constant changeover.
From DE 39_27 142 Al, a bobbin winding device is known with which the contact pressure of the cross-wound bobbin on the thread guide drum is capable of being reduced in the area of a ribbon winding zone.
With this known bobbin-winding device, the creel is connected to an electromechanical torque actuator, for preference a DC motor operating from standstill, which in turn is connected to a control device. A bobbin winder brake can also be controlled via the control device.
When a ribbon winding zone is reached, the creel is subjected to an "Unload" command by the torque actuator, while at the same time the cross-wound bobbin held in the creel is braked.
The ribbon disruption processes of the state of the art have so far proved unsatisfactory, since these processes do not provide for a precise regulation of the angular velocity of the cross-wound bobbin within the ribbon winding zone.. With the known devices it has not been possible to provide sufficient precision in maintaining a predetermined angular velocity either by regulating the imposition pressure with which the cross-wound bobbin is applied to the thread guide drum, or by means of the bobbin brake.
In particular, in the slip-free run-out phases of

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winding, with the known ribbon disruption processes problems have repeatedly arisen due to the occurrence of what are known as residual ribbons.
Taking the foregoing state of the art as a basis, the invention is based on the objective of improving the known ribbon disruption processes.
This task is fulfilled by the invention through a process having the feature that the winding speed of the cross-wound bobbin is constantly determined and processed in a control unit in such a way that on reaching or shortly before reaching an image winding zone the pregiven winding speed on account of the diameter of the cross-wound bobbin be reduced by defined adjustment of the support pressure, with which the cross-wound bobbin rests on the thread guiding drum, to a winding speed that lies beiow that critical winding speed, which a cross-wound bobbin with the same diameter driven without loop would have.
The process according to the invention has the advantage that ft. reliably circumvents ribbon formation areas with relatively low technical investment, and therefore economically.
This means that, when the control device detects that the cross-wound bobbin has attained a particular diameter, and has therefore reached a ribbon:winding zone, the angular velocity of the cross-wound bobbin will be reduced by a defined regulation of the pressure with which the cross-wound bobbin is imposed on the thread guide drum, to a value which is below the critical angular velocity of the cross-wound bobbin and therefore of the ribbon winding zone.
These critical angular velocities, at which ribbon winding occurs, arise at specific known cross-wound bobbin diameters, if a cross-wound bobbin is driven without slippage.
For preference, the angular velocity of the cross-wound bobbin is reduced in this situation,

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Claim 2 to a level which corresponds to an angular veloeity which would be featured by a cross-wound bobbin driven without slippage due to its diameter when leaving the ribbon winding zone. The angular velocity provided for in this situation is precisely maintained by the corresponding regulation of the laying pressure until departure from the ribbon winding zone.
In this way, the residual ribboning, which has hitherto caused disruption, can be reliably avoided.
The relatively low technical investment in this
situation is the result, inter alia, of the fact that

the cross-wound bobbin, as represented inr claim 3 can

be subjected in the area of the ribbon winding zone with
a constant or almost constant braking moment, which is only relatively weak, because the regulation of the rotational speed of the cross-wound bobbin is effected solely by the imposition pressure of the cross-wound bobbin on the thread guide drum. Such constant braking moment, which as a rule is not very high, can also be achieved with the bobbin brakes used hitherto.
In an advantageous embodiment of the invention, it is even possible for the initiation of a braking moment by means of the bobbin brake to be done away with entirely^--¦ Instead, as represented in it is possible for the braking moment to be"-derived also from the air friction of the cross-wound bobbin and/or the bearing friction of the bobbin holder and/or the friction of the thread which is to be wound.
The defined regulation of the imposition pressure of the cross-wound bobbin on the thread guide drum, and therefore the precise adjustment of the revolution speed of the cross-wound bobbin, is effected, as represented

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in by means of a torque sensor, designed as a stepped motor. The stepped motor in this situation is a constituent part of a-creel_adjustment device, as described in detail in DE 198 17 363.3.
Further details of the invention are provided on the basis of an embodiment explained hereinafter on the basis of the drawings.
These show:
Fig. 1 A schematic diagram of the revolution speed curve of a cross-wound bobbin during its winding process, under the application of a first embodiment of the process according to the invention, in particular in the area of a ribbon winding zone,
Fig. 2 A schematic representation of the revolution speed curve of a cross-wound bobbin during its winding process, under the application of an alternative embodiment of the process according to the invention,
Fig. 3 A perspective view of the bobbin winding device, which allows for the implementation of the process according to the invention.
The diagrams shown in Figures 1 and 2 in each case show, on the basis of a curve 22, the revolution speed curve of a cross-wound bobbin during its winding process, under the application of the ribbon disruption process according to the invention.
In this case, in particular, the revolution speed curve and the angular velocity respectively of a cross-wound

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bobbin are shown in the area of a ribbon winding zone, BWZ. Shown on the ordinate in this situation is the angular velocity w of the cross-wound bobbin, and on the abscissa the diameter d of the cross-wound bobbin.
Fig. 1 in this situation shows a first embodiment, and Fig. 2 an alternative embodiment.
As can be seen from the curve 22 in Figures 1 and 2, the angular velocity w of the cross-wound bobbin 4 decreases constantly as the bobbin diameter d increases. At a bobbin diameter dl, in this situation, a critical area is reached, referred to as a ribbon winding zone, BWZ. The ribbon winding zone BWZ extends on both sides of a critical cross-wound bobbin diameter dk, at which, as already indicated in the introduction to the preamble, a winding ratio pertains between the thread guide drum and the cross-wound bobbin, which leads to the occurrence of what are referred to as ribbon windings. The precise dissemination of the critical ribbon winding zone BWZ in this context is dependent on various factors, such as the yarn number, the yarn material, the winding density, and so on.
According to the ribbon disruption process according to the invention, illustrated in Fig. 1, the angular velocity wl, which the cross-wound bobbin 4 attains due to its diameter dl on reaching the ribbon winding zone, is initially reduced to an angular velocity w2, and this angular velocity w2 is maintained constant while passing through the ribbon winding zone BWZ. The angular velocity w2 in this situation corresponds to an angular velocity at which a cross-wound bobbin with the diameter d2 would rotate when driven by the thread guide drum at constant speed and without slippage.

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The angular velocity w2 in this situation is clearly below the angular velocity which would be featured by a cross-wound bobbin with the critical diameter dk, driven without slippage.
At the end of the ribbon winding zone BWZ, i.e. when the cross-wound bobbin 4 has attained the diameter d2, the angular velocity w2 then again corresponds to the revolution speed curve shown on the basis of the curve 22, of a cross-wound bobbin driven almost free of slippage.
The process described is repeated as soon as the cross-wound bobbin has reached the next ribbon winding zone BWZ in its winding process.
In the embodiment according to Fig. 2, on attaining a cross-wound bobbin diameter dl, i.e. at the beginning of the ribbon winding zone BWZ, the angular velocity wl of the cross-wound bobbin is likewise initially reduced to an angular velocity w2. The angular velocity w2 in this situation is below the angular velocity of the cross-wound bobbin which is given by the critical cross-wound bobbin diameter dk.
As indicated in Fig. 2, the angular velocity w2 is further reduced when moving through the ribbon" winding zone BWZ, to be raised again at the end of the ribbon winding zone, by the appropriate loading of the creel, to an angular velocity which corresponds to the angular velocity of a cross-wound bobbin with the diameter d2, driven without slippage.
The ribbon disruption process described can, in this situation, be used instead of a known ribbon disruption process as referred to in the introduction to the

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abstract, or in addition to such a ribbon disruption process.
Figure 3 shows a device which allows for the implementation of the ribbon disruption process according to the invention.
In the winding station housing 2 of a work station designated overall by 1 of a textile machine manufacturing cross-wound bobbins, a thread guide drum 3 is mounted on bearings, which is driven by an electric motor (not shown) . The thread guide drum 3 in turn drives a cross-wound bobbin 4, by friction.
The cross-wound bobbin 4 in this situation is mounted in a creel 5, which is connected in a rotationally-resistant manner to a pivot axle 6. The pivot axle 6 is arranged parallel to the axis of the thread guide drum 3, and is mounted on the winding station housing 2 with limited pivoting capacity.
The creel 5 is provided, as usual, with two bobbin arms 7 and 8, which are provided with rotatably mounted bobbin boards. Held between the bobbin boards is an empty bobbin holder, onto which a thread is wound to form the cross-wound bobbin 4. At least one of the bobbin arms 7, 8 is in this case capable of being pivoted to the side away from the cross-wound bobbin, together with the bobbin board, in a manner not described in greater detail, with the result that a full cross-wound bobbin is removed from the creel 5, and an empty bobbin holder can be inserted.
At the pivot axle 6 of the creel 5, a torque sensor is engaged. This torque sensor features, inter alia, a connection disk 9, connected in a rotationally-resistant

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manner to the pivot axle 6, as well as a toothed wheel 10, rotatably mounted coaxially to the pivot axis 6. The connection disk 9 is provided with connection bolts 11, which point towards the toothed wheel 10. Provided on the toothed wheel 10 are corresponding connection bolts 12. Between the connection bolts 11 of the connection disk 9, and the connection bolts 12 of the toothed wheel 10, identical spring elements 13 are fitted as transfer elements, in the form of helical springs, which are deformed in opposite directions at the relative rotation of the toothed wheel 10 and the connection disk 9.
The rotatably-mounted toothed wheel 10 engages in comb fashion with a pinion 14 of a reduction gear, of which the outer rim 15 is connected by a drive pinion 16 to a stepped motor 17. Because the drive pinion 16, the outer rim 15, and the pinion 14 are mounted in a rot a table manner on the winding station housing, it is possible for every rotational movement of the stepped motor 17, secured at the winding station housing 2, to be transferred via the reduction gear, for example in a ratio of 1 : 25, to the toothed wheel 10. The stepped motor 17, which is designed for example for individual steps of about 1.8°, is actuated by means of a winding station computer 18, and accordingly carries out a predetermined number of revolutions or a predetermined number of individual steps, which result in a torque force at the creel 5 by means of which the contact pressure of the cross-wound bobbin 4 on the thread guide drum 3 can be adjusted.
Function of the device and sequence of the process according to the invention:
By means of sensors 23 and 24, which are connected by means of corresponding signal lines 25, 26 to the

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winding station 18, both the revolution speed of the cross-wound bobbin 4 as well as the revolution speed of the thread guide drum 3 are constantly monitored. From this data, and from the known design data of the machine, the current winding ratio of the cross-wound bobbin 4 is constantly calculated in the winding station computer 18.
When the diameter d of the cross-wound bobbin 4 approaches a ribbon winding zone BWZ, i.e. an area in which, with slip-free drive, the revolution speed of the thread guide drum amounts, for example, to a whole-figure multiple of the revolution speed of the cross-wound bobbin, the revolution speed of the cross-wound bobbin us reduced from the revolution speed nl, determined by the diameter of the cross-wound bobbin, to an adjustable revolution speed n2.
maintaining of this revolution spe6d, is effected in
this case by the fact that the cross-wound bobbin 4 on the one hand, for example by means of the bobbin brake 20, which is connected via a signal line 21 to the winding station computer 18, is subjected to a constant brake moment, and, on the other hand, the imposition pressure with which the cross-wound bobbin 4 lies on the thread guide drum, is reduced by a defined raising of the. creel 5, By the corresponding increase or decrease of this imposition pressure, the desired revolution speed n2 of the cross-wound bobbin 4 can in this situation be precisely adjusted.
That is to say, ribbon winding can be avoided by the fact that, by means of the stepped motor n, the toothed wheel 10 is rotated into a position "hich corresponds to

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a calculated contact pressure of the cross-wound bobbin 4 on the thread guide drum 3. Control of the contact pressure, as a function of the winding progress of the cross-wound bobbin or of the cross-wound bobbin diameter, by adjusting the stepped motor 17, is effected in this case in the winding station 18, by the use of a control program. A control program of this type calculated the required position of the stepped motor 17, expressed as positive or negative steps, for example on the basis of the sensor data described earlier, which are passed to the winding station computer throughout the progress of the winding procedure.

WE CLAIM
1- A process for the operation of a textile machine for the manufacture of cross-wound bobbins or cheeses, which produces cross-wound bobbins in accordance with the "random winding" winding technique, in which situation, in order to avoid ribbon winding, the imposition pressure of the cross-wound bobbin on (he thread drive drum is reduced, and the cross-wound bobbin Is at the same time subjected to a braking moment,
- the angular velocity w of the cross-wound bobbin (4) is constantly
monitored and processed in a control device (18) in such a way
- characterized in that
- that when a ribbon winding zone (BWZ) is reached, or shortly
before this, the angular velocity w1, which is predetermined by the
diameter d1 of the cross-wound bobbin (4), is reduced to an
angular velocity w2 is below critical angular velocity wk, by the
adjustment of the imposition pressure with which the cross-wound
bobbin (4) is imposed on the thread guide drum (3), the said
angular velocity wk, which would be featured by a cross-wound
bobbin with the diameter dk driven without slippage.
2. A process as claimed in claim 1, wherein the angular velocity w1, predetermined by the diameter d1 of the cross-wound bobbin (4), is reduced to an angular velocity w2, at or shortly before a ribbon winding zone (BWZ) is reached, by the defined adjustment of the Imposition pressure with which the cross-wound bobbin (4) lies on the thread guide drum (3), the said angular velocity w2 corresponding to an angular velocity which would be featured by a cross-wound bobbin (4) with the diameter d2, driven without slippage, on leaving the ribbon winding zone (BWZ),
and
- that the angular velocity w2 of the cross-wound bobbin (4) is
maintained until the ribbon winding zone (BWZ) has been passed
through.

3. A process as claimed in claim 1 and 2, wherein the cross-wound bobbin
(4), when passing through a ribbon winding zone (BWZ) is subjected to a
constant, braking moment, and the regulation of the angular velocity w2 of
the cross-wound bobbin is effected by means of a corresponding defined
adjustment of the imposition pressure with which the cross-wound bobbin
(4) is (aid on the thread guide drum (3).
4. A process as claimed in claim 1 to 3, wherein the braking moment is
determined by the air friction of the rotating cross-wound bobbin (4).
5. A process as claimed in one of the preceding claims, wherein the braking
moment is determined by the bearing friction of the bobbin mounting of the
creet (5), which secures (he cross-wound bobbin (4).
6. A process as claimed in one of the preceding claims, wherein the thread
moment derived by friction during the rewinding process is used as the
braking moment.
7. A process as claimed in one of the preceding claims, wherein the
adjustment of the imposition pressure with which the cross-wound bobbin
(4) is laid on the thread guide drum (3) is effected by means of a torque
sensor designed as a stepped motor (16).
A process for the operation of a textile machine for the manufacture of cross-wound bobbins or cheeses, which produces cross-wound bobbins in accordance with the "random winding" winding technique, in which situation, in order Jo avoid ribbon winding, the imposition pressure of the cross-wound bobbin on the thread drive drum is reduced, and the cross-wound bobbin is at the same time subjected to a braking moment, the angular velocity w of the cross-wound bobbin (4) Is constantly monitored and processed in a control device (18) in such a way characterized in that when a ribbon winding zone (BWZ) is reached, or shortly before this, the angular velocity w1, which is predetermined by the diameter d1 of the cross-wound bobbin (4), is reduced to an angular velocity w2, by the adjustment of the imposition pressure with which the cross-wound bobbin (4) is imposed on the thread guide drum (3), the said angular velocity wk, which would be featured by a cross-wound bobbin with the diameter dk driven without slippage.


Documents:


Patent Number 208949
Indian Patent Application Number 00496/CAL/1999
PG Journal Number 33/2007
Publication Date 17-Aug-2007
Grant Date 16-Aug-2007
Date of Filing 26-May-1999
Name of Patentee W. SCHLAFHORST AG & CO.
Applicant Address POSTFACH 100435, D-41004, MONCHENGLADBACH,
Inventors:
# Inventor's Name Inventor's Address
1 GERARD KUSTERS KREUZSTRASSE 19, 52538 SELFKANT-HAVERT,
2 CHRISTIAN STURM STEINSTRASSE 78, 47798 KREFELD, GARMAN
3 FRANZ-JOSEF FLAMM VICHTER STRASSE 96, 52224 STOLBERG; GERMANY
PCT International Classification Number B65H 54/38
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 P19829597.9 1998-07-02 Germany