EP0016871B1 - Method and device for obtaining predetermined and exact yarn lengths on cross spools - Google Patents

Abstract

The invention relates to a method and an apparatus for obtaining pedeterminable and exact yarn lengths on cross-wound bobbins. It is thereby assumed that all complete cops substantially have the same yarn length and of these only individual partial or remnant cops may contain less yarn. By determining the operation periods or the number of revolutions of the grooved cylinder or the cross-wound bobbin in relation to the yarn length of complete cops, counting values are introduced into a control unit which are totalled in this unit and compared with a set value which corresponds to the yarn length of the complete cross-wound bobbin. As soon as the set value has been obtained, the winding method is interrupted. Further developments of this method enable operating periods or the number of revolutions of different winding points to be compared and thereby to recognize defecting winding methods.

Description

The invention relates to a method for achieving predeterminable and precise yarn lengths on cross-wound bobbins during the winding process, in which full spinning cops and possibly existing partial cops are rewound and the winding process for the cross-wound package in question is terminated when the desired yarn length is reached. Furthermore, the invention is directed to an apparatus for performing this method.

Cross-wound bobbins often have to be produced in the textile industry, of which a plurality are then always wound onto a warp beam at the same time. It is essential that when the first package is empty, the warp beam must be stopped and the rest of the package must be removed.

New packages can then be wound from these packages of packages. Since the bobbin with the shortest yarn length in each case is decisive for stopping the warp beam, all the bobbins that have not yet been completely unwound and have comparatively large residual quantities must be removed, rewound or processed in some other way. Accordingly, it can be seen that the practically existing considerable inaccuracies in the yarn lengths of cross-wound bobbins cause considerable disruptions in the production process and thus also significant costs.

In automatic winding machines, several spinning cops are usually wound one after the other on a cheese. With makeshift procedures and devices, an approximate equality of the length of the cheese is sought. Known devices for this purpose are e.g. B. rings that are suspended from a chain above the package on the automatic winder, the package starting to reach the desired diameter to touch the suspended ring during further winding and thus set in oscillating movements. This is then visually recognized by the operating personnel and is a signal that the cheese should now be removed. It turns out that the accuracy of this device is in the order of 5 to 10% in practice.

From CH-A-397 4'99 devices for thread length measurement on cross winding machines are known, in which the spooled thread length is determined with the aid of a measuring wheel with a coupled counter, the thread looping around the measuring wheel at least once. The disadvantage here is that a certain mass has to be set in motion or kept in motion when the counter is driven and it is necessary to give the thread a relatively large tension in order to at least approximately without a slip between the thread and the measuring accuracy impairing the measuring accuracy To be able to drive measuring wheels. The large thread tension required leads to difficulties for many materials to be processed, and the complicated insertion of the thread is also a considerable disadvantage.

Furthermore, this CH-A-397499 describes the possibility of measuring the wound thread length only by determining the number of revolutions of the spool drum in the cross winding machine itself. However, this measurement is associated with considerable measurement errors because it is difficult to precisely define the thread path in the grooves of the groove drum and, moreover, an annoying slip always occurs between the thread and the groove drum.

Finally, this CH-A-397 499 describes a method in which a measuring wheel no longer directly drives a counter, but rather scans the measuring wheel via a light barrier and thus counteracts inertia effects and friction effects. These measures do not make it possible to eliminate the fundamental disadvantages of using measuring wheels, which in any case represent a foreign body in the yarn, so that, despite the reduction in friction and inertia effects, the achievable accuracy remains unsatisfactory and does not allow the accuracy during winding to consider residues from warp beams as waste. The resulting residues are too large and therefore too valuable.

It is an object of the invention to further develop the method of the type mentioned at the outset in such a way that the lengths of yarn obtained on the cross-wound bobbins are as equal as possible and thus only minimal residual amounts of yarn are obtained when winding cross-wound bobbins onto a warp beam. The method should be feasible in such a way that it is possible to work without additional agents which impair the yarn.

This object is achieved according to the invention in that a reference size is formed from the precisely known yarn length of error-free full spinning cops by division with an auxiliary size which is at least substantially representative of the yarn length wound from the error-free spinning cops onto the package, and the predetermined yarn length the package is determined by summing the yarn length of the copse or partial copse determined by means of an auxiliary size measurement and the reference size.

The method according to the invention makes it possible to achieve yarn lengths which can be predetermined almost exactly on packages, since inertia effects, friction problems and slippage inaccuracies play no role in the length determination.

The runtime is preferred as the auxiliary variable used for the unwinding of an error-free, full spinning cop, since time measurements can be carried out precisely and without problems.

According to an advantageous embodiment of the method according to the invention, the reference size is adapted to changes during the winding of the cheese. In this way, the demand for the same possible lengths of yarn on the individual packages can be optimally realized if there is a different slip for the various spinning copes when the package is wound.

It is also advantageous to re-determine the reference size for each spinning cop, to compare it with the previously determined reference sizes and to correct it at least partially for the further determination of the yarn length. As a result, changes resulting from different yarn qualities and the like can be taken into account.

The reference sizes of different winding positions are assessed according to a further embodiment variant of the invention, and depending on this assessment, a characteristic course of the reference sizes during the winding of the packages is made recognizable, a signal being emitted in the event of significant deviations in the characteristic course of the winding of the package. that indicates this deviation and allows the detection of a faulty winding unit.

An advantageous device for performing the method according to the invention is characterized by a measuring device for determining an auxiliary variable for game length measurement, an arithmetic unit with at least one input point for the length of an error-free, full spinning cop and the desired length of the cheese and at least one input for the signal the measuring device and an output, which comes into action when the calculated and desired yarn length match.

Further advantageous embodiments of the invention are specified in dependent claims 3, 4, 7, 10 and 12 to 1'5.

• 'Fig. 1 als Strichdiagramm die Verteilung von Referenzwerten einer Anzahl von Spinncopsen bei Bewicklung einer Kreuzspule,
• Fig. 2 als weiteres Strichdiagramm die Verteilung der Ablaufzeiten von vollen und teilweise vollen Spinncopsen,
• Fig. 3 die Längesumme einer Anzahl Spinncopse,
• Fig. 4 schematisch die Spulstelle mit Mess-und Auswerteorganen.

The invention is explained in more detail below with reference to the drawing; in the drawing shows:

• 'Fig. 1 is a line diagram showing the distribution of reference values of a number of spinning copes when winding a cheese,
• 2 shows, as a further line diagram, the distribution of the expiry times of full and partially full spinning cops,
• 3 shows the total length of a number of spinning cops,
• 4 schematically shows the winding unit with measuring and evaluation elements.

On a ring spinning machine, the delivery cylinder generally has a certain diameter at all spinning positions. Therefore, the same amount of Garrt is inevitably produced on all spinning stations. Since all the cops are spun at the same time, they inevitably have the same length on the same ring spinning machine. With a counter, for example, with which the number of revolutions of the front cylinder is counted, the ring spinning machine can be switched off each time a certain yarn length is reached. This means that not only is the length of the yarn copes the same within a so-called decrease, but there are also no differences from one decrease to another. Likewise, there are no differences between different ring spinning machines.

In the method according to the invention, this exactly the same length of the yarn copes Lv is now used as the base value for the formation of the length of the cheese package Lks. For example, exactly 20 spinning cops can each be wound onto a cheese. These packages would then be very precise with regard to the length of the yarns wound on them.

• 1. In den seltensten Fällen wird die gewünschte Garnlänge ein ganzzahliges Vielfaches der Spinncopse sein.
• 2. Am Anfang einer Kreuzspule kann nur selten mit vollen Spinncopsen begonnen werden, weil der von der vorgängigen Kreuzspule begonnene Spinncops aufgesteckt bleibt.
• 3. Spinncopse, die beim Spinnprozess einen Fadenbruch aufgewiesen haben, sind kürzer und dürfen daher nicht zur Bildung von Referenzwerten verwendet werden.

In practice, however, the following circumstances must also be taken into account:

• 1. In the rarest of cases the desired yarn length will be an integral multiple of the spinning cops.
• 2. At the beginning of a package, full spinning cops can only rarely be started because the spinning cop started by the previous package remains attached.
• 3. Spinning cops that have broken threads during the spinning process are shorter and therefore must not be used to form reference values.

• - Laufzeit beim Bewickeln der Kreuzspule;
• - Anzahl der Umdrehungen der Nutentrommel;
• - Anzahl der Umdrehungen der Kreuzspule.

To solve these problems, another basic idea of the present invention lies in the following: With auxiliary variables, the length of the yarns wound on packages can be determined with an accuracy of a few percent. As auxiliary variables come e.g. B. Consider the following:

• - Running time when winding the package;
• - Number of revolutions of the grooved drum;
• - Number of turns of the package.

The list is not exhaustive. These auxiliary variables are now in accordance with the inventive method in relation to the basic size, z. B. the yarn length of a spinning cop, brought, and thus the reference size is determined.

If one starts from the fact that all spinning cops without thread breaks have the same length, the auxiliary sizes mentioned and the length Lv of the full spinning cops can be used to obtain a precisely defined relationship to the length of the yarns wound on the package via the reference size , even if partial cops with a yarn length Lt have been rewound or the winding process is still in progress (remaining length Lr).

The method according to the invention is illustrated below using an example for better clarification: The length of the spinning cops without thread breaks, for example, would be 2000 m. All ring spinning machines that produce yarns for the winding process in question are to be set so that the spinning copes have an exact length of 2000 m. In this example, the runtime is selected as an auxiliary variable. It is assumed that the circumferential speed of the grooved drum is 1000 m / min. This results in a winding speed of approximately 1000 m / min. With a yarn length Lv of the spinning cop of 2000 m and exactly 1000 m / min winding speed, this would be exactly 2 minutes. However, because the winding speed does not exactly match the circumferential speed of the slot drum, the running time is not exactly 2 minutes. It is now assumed that the runtime is 2.15 minutes; the effective winding speed is therefore 930 m / min. The reference value Rv for the start of the cheese is thus obtained. If, when starting the next package, a spinning cop is no longer full, which is very likely, the existing reference value of 930 m / min can now be used.

If, for example, a runtime of the no longer full cops of 0.9 minutes is determined for the next package, this results in a length of 0.9 minutes x 930 m / mm = 837 m.

In the same way that the length Lt of partial cops can now be determined precisely according to the invention at the beginning of a package, this also applies to the end of the package if a full cop (remaining length Lr) is no longer required to reach it.

Practice shows, however, that the conditions change when winding the package. At the start of winding on a cheese, for. B. the slip between the grooved drum and the package can be greater or smaller than at the end and the length of the yarn when winding the package for one revolution of the same at the beginning is much smaller than with the full package. This fact can also be taken into account in the method according to the invention by determining the reference value Rv corresponding to the progressive formation of the cheese. For the practical implementation of the method according to the invention, the following procedure could be used, for example: A full spinning cop (No. 1) is plugged into the sputtering machine at the beginning of a package. As in the previous example, the runtime is selected as an auxiliary variable. Now measure the time until the spinning cop has expired. The reference value Rv, as is to be used at the beginning of a cheese, is thereby obtained. Now the next spinning cop (No. 2) is put on. Its run length is the reference value Rv for the next piece of the package. The procedure is now the same until the cheese is full. Figure 1 shows a corresponding example of a distribution of reference values for a package. These reference values are saved and used as the basis for the winding of the following packages.

In the above explanations, it was assumed that all spinning cops have the same length Lv. However, the case must also be taken into account that thread breaks have occurred at individual spinning positions and the cops in question therefore no longer have the desired length. It is obvious that the thread breaks can only reduce the yarn length of the cops in question, but not increase them. There is no circumstance at all in which the thread length on the spinning cops could be increased.

From the reference value Rv, the thread running time can now be determined in the opposite sense if the end of an expired spinning cop is to be expected. If a thread break has occurred, the end of the spinning cop comes earlier than expected. It is important that the shortening is often not small, but is several percent. From the not very precise reference size, e.g. B. can be determined with sufficient certainty via a transit time measurement, as a rule, whether a spinning cop with thread break has been present or not. It is thus possible to recognize these spinning cops, which have had at least one thread break, and to exclude them as reference values Rv.

If spinning cops with thread breaks were already in the first pass of a package, a deviation in the running times should occur. A corresponding example is shown in FIG. 2. Cops No. 4 and 9 are obviously too short spinning cops. These deviations can be easily recognized and the relevant reference values can be eliminated. In the further course of the rewinding process, the reference values Rv or the expiry times can be checked again and again. If necessary, they must also be corrected. This can e.g. B. may be necessary by changing the conditions.

The reference values Rv for winding a cheese are now defined. Intermediate values can be interpolated. Since the winding of all other packages on the same winding station remains most likely the same, partial cops with yarn lengths Lt can also be used at any point on the package.

FIG. 3 shows a graphical representation of the method of winding according to the invention when producing a package with an exact length of yarn. Section A is the rest Lr of the spinning cops still attached. The beginning of the same was still used for the last cheese. The length Lr of the remainder can be determined quite precisely from the reference value Rv. The distances B and C correspond to the target length Lv and can therefore be assumed to be full spinning cops, ie their length is exact. Section D is obviously a partial cop (possibly spinning cops with thread breakage). Its length Lt can be determined from its running time with sufficient accuracy. Sections E, F, G and H are full copse. From the length of the partial cops Lt and the number of full copse Lv, the length wound up can always be exactly determined. At the end of section H z. For example, it is known exactly how much yarn is already on the package and what remaining length Lr can still be unwound from the cops I until the desired exact length Lks of the package is reached.

The Cops I yarn can now be cut off when the desired length is reached, for example with the help of an electronic yarn cleaner. With the help of a signal, for example, the winder can recognize that this package has reached the desired length and is to be replaced. When the cross-wound bobbin is replaced automatically, an automatic system can be initiated using the signal mentioned.

In the example mentioned, the runtime was chosen as the auxiliary variable, the reference value Rv being calibrated from the length of the cops. In this case, the dimension of the reference value Rv is "length per unit time _" , for example m / min. As mentioned at the beginning, other auxiliary variables can also be used. The choice of the running time is particularly favorable because many of them are found on automatic winding machines There are already electromechanical or electronic thread monitors that indicate the running time.

It is also advantageous to compare the reference values Rv from different winding units with one another. The values can often differ from each other, e.g. B. by differently set thread brakes, so that there are different thread tensions and thus different slip ratios between the driving grooved drum and the driven package. If the deviations are too large, a signal can also be given, because it is very likely that the conclusion can be drawn that something is wrong with the winding units concerned. The present method therefore also makes it easier to find faulty winding positions. 'The characteristic course of the reference size can also be a quality feature of the winding process.

However, the process of including reference values, maturities, etc. is quite time consuming. Today's electronics, especially the use of microcomputers, allow the previously described processes to be programmed accordingly. Time measurements can be carried out automatically, reference values can be stored in the memory of the microcomputer, etc.

Not only can the reference values be recorded, but their continuity can also be checked automatically. The comparison of the winding units is also possible automatically. If the deviations are too great, a signal can be triggered, which creates a device with which incorrectly operating winding units can be displayed.

4 schematically shows a winding unit 20 with sensors and the evaluation device. The yarn 2'2 running from the spinning cops 21 passes through a thread monitor 27, a thread separating device 28 and is wound onto the cheese 23 via the spool drum 24. The thread monitor 27 can be part of a yarn cleaner, for example, which also contains the cutting device 28. The thread monitor 27 emits a signal to the arithmetic logic unit 36 during the duration of the yarn run, which triggers a count in this, for example. If the number of revolutions of the grooved drum 24 or the cross-wound bobbin 23 are used as counting elements, sensors 31 and 32 are used at corresponding points, which emit the required counting values.

An input point 37 is assigned to the arithmetic unit 36, through which both the length Lv of a full spinning cop 21 and the desired total length Lks of the cheese are entered. Furthermore, the arithmetic logic unit 36 has a further input 3'5, through which the signals of the thread monitor 27 or the sensors 31 or are applied. The output 39 of the arithmetic unit 36 actuates the cutting device 28 on the one hand, and on the other hand it can emit control signals for influencing the winding process.

Claims (15)

1. A method of achieving predeterminable and accurate yarn lengths on cross bobbins (23) during the winding process, wherein full spinning cops (21) and, optionally, available part cops are rewound and wherein, on reaching the desired yarn length, the winding process for the cross bobbin in question is terminated, characterised in that a reference value (Rv) is formed from the accurately known yarn length (base value Lv) for fauitfree full spinning cops (21) through division by an auxiliary value which is at least substantially representative of the yarn length rewound from a faultfree spinning cop onto the cross bobbin (23), and in that the predetermined yarn length (Lks) on the cross bobbin is determined by summing the yam lengths (Lv, Lt, Lr) of the full spinning cops or the part cops specified using an auxiliary value measurement and the reference value.

2. A method in accordance with claim 1 and characterised in that the running time required to unwind a full, faultfree spinning cop (21) is used as the auxiliary value.

3. A method in accordance with claim 1 and characterised in that the quotient of the number of revolutions of the grooved drum (24) and the running time required to unwind a faultfree full spinning cop (21) is used as the reference value (Rv).

4. A method in accordance with claim 1 and characterised in that the quotient of the number of revolutions of the cross bobbin (23) and the runningtime required to unwind a falutfree full spinning cop (21) is used as the reference value (Rv).

5. A method in accordance with claim 1 and characterised in that the reference value (Rv) is matched to changes during the winding of the cross bobbin (23).

'6. A method in accordance with claim 1 and characterised in that the reference value (Rv) is determined anew for each spinning cop (21), is compared with the previously determined reference value (Rv) and is at least partially corrected for the further determination of the yarn length (Lks).

7. A method in accordance with claims 1 and 6 and characterised in that spinning cops (21) having running times which differ considerably from those of the preceding spinning cops are not used for forming reference values (Rv).

8. A method in accordance with claim 1 and characterised in that the reference values (Rv) of various windig stations are judged and thereby a characteristic pattern for the reference values (Rv) during the winding of the cross bobbins (23) is made recognisable.

9. A method in accordance with claims 1 and 8 and characterised in that, on the occurence of considerable deviations from the characteristic pattern during winding of the cross bobbin (23), a signal is generated which points to this deviation.

10. A method in accordance with claims 1 and 8 and characterised in that, on the occurrence of considerable deviations of individual winding stations from the characteristic pattern for the winding of the cross bobbin (23) from the average value for different winding stations, a signal is given which points to this deviation.

_'11. Apparatus for carrying out the method of one or more of the preceding claims and characterised by a measuring device for determining an auxiliary value for the measurement of yarn lengths; by a computing device (36) with at least one input position for the length (Lv) of a faultfree, full spinning cop (21), and for the desired length (Lks) of the cross bobbin (23), and with at least one input (35) for the signal from the measuring device; and by an output (39) which comes into action when the calculated and desired yarn lengths (Lks) are the same.

12. An apparatus in accordance with claim 11 and characterised by a sensor (31) for determining the speed of rotation of the grooved drum (24) which serves as the auxiliary value.

'13. Apparatus in accordance with claim 11 and characterised in that a time counter is provided for determining the running time of a spinning cop (21) which serves as the auxiliary value.

1'4. Apparatus in accordance with claim 11 and characterised in that a sensor (32) is provided for determining the number of revolutions of the cross bobbin (23) which serves as the auxiliary value.

1'5. Apparatus in accordance with claim 11 and characterised by a microcomputer in which the functions of counting, of storage, of comparison, of summation and of evaluation are integrated.

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