WO2007090425A1

WO2007090425A1 - Method and device for overhead drawing off of a yarn

Info

Publication number: WO2007090425A1
Application number: PCT/EP2006/001172
Authority: WO
Inventors: Göksel Karaarslan; Marc Schaad
Original assignee: SSM Schärer Schweiter Mettler AG
Priority date: 2006-02-10
Filing date: 2006-02-10
Publication date: 2007-08-16

Abstract

A method and a device are disclosed, for overhead drawing off of a yarn (4) wound on a yarn spool (3). The method is based on the following steps. preparation of the yarn spool (3) for overhead drawing off in a yarn spool housing (2) and overhead drawing of the yarn (4) from the yarn spool (3) through a yarn guide (7) positioned in the thread run of the yarn (4) at a separation from the yarn spool housing (2). At least one thread tension of the yarn (4) is determined as a control parameter (19), for example by means of a thread tension sensor (16) in the thread run after the yarn guide (7) and the separation of the yarn guide (7) from the yarn spool housing (2) is varied by means of a yarn guide actuator device (10) controlled by a control unit (20), depending on the control parameter (19). The method is suitable for elevated speed drawing off of the yarn from the yarn spool.

Description

Method and device for upside down pulling off a yarn

The invention relates to a method for the overhead removal of a wound on a yarn package yarn with the steps providing the yarn package for pulling overhead in a Garnspulenaufnahme, and overhead pulling the yarn from the yarn package by one in the yarn path of the yarn at a distance from the yarn package positioned Garnführung through and a device for carrying out the method.

For unwinding a yarn from a yarn package commonly referred to as a supply spool, two methods are used in yarn processing machines.

On the one hand, the yarn can be unwound tangentially from a supply spool with the aid of a special delivery system (tangential deduction). To perform this operation, at least one additional drive is necessary. In order to unwind the feed bobbin of the yarn tangentially, it is positioned with its axis parallel to the axes of rotation of delivery mechanisms used for unwinding. When tangential deduction two variants are distinguished. In the free-running tangential trigger, the feed bobbin sits on a freely rotating sleeve without its own drive. The freely rotating trigger is only applicable at low process speeds. When driven tangential trigger the rotation of the supply spool is driven by support rollers. This driven tangential trigger is applicable for high production speeds of elastic yarns. Next is known overhead peeling off yarns. When pulling off overhead, the feed bobbin usually does not rotate itself.

The yarn is guided by the yarn package through a yarn guide, which is located in a region of the elongated longitudinal axis of the supply bobbin on the supply spool. When pulling off overhead forms a so-called balloon. This balloon is characterized by the unwinding, i. formed during removal of the yarn between the yarn package, more specifically between the current departure of the yarn (stroke) on the yarn package and the yarn guide formed in the thread by the unwinding and the forces generated thereby on the thread about the extended longitudinal axis of Spool swings.

This can form a balloon with different diameter and shape. The forming form depends on various parameters such as diameter, shape, yarn type and winding type of the yarn package. For example, As the yarn spool picks up, the peripheral speed of the yarn package decreases as the diameter of the yarn package decreases as it is being unwound, thereby increasing the relative take-off speed, i. the difference of the take-off speed and the peripheral speed, increases with decreasing diameter. Of the

Diameter of the balloon tends to increase, because the causative centrifugal forces increase with increasing relative

Off speed. The latter causes the tendency to disturb the geometry of the balloon increases accordingly. The yarn guide through which the yarn is made has a dampening effect on said yarn

Vibration. The distance between Garnspulenaufnahme and yarn guide limits the length on which the balloon can form. It turns out that the unwinding of the yarn is usually carried out on trouble-free, if a homogeneous first-order balloon is formed. Such a balloon has exactly one belly. DH The wavelength of the shrinkage of the yarn in the Balloon in the withdrawal direction is twice as large as the distance between Garnspulenaufnahme and yarn guide, but variations of this wavelength consist of the stroke of the thread, but in the case of a homogeneous balloon, especially if the distance between Garnspulenaufnahme and yarn guide, more precisely, the relation between the Distance and the maximum possible stroke, is sufficiently large, do not lead to significant disturbances of the balloon. In particular, in bobbins with a low quality of yarn winding, ie poor coil construction, the balloon can collapse due to disturbances caused thereby and / or it enters a balloon of higher dimension, ie a balloon with a lower wavelength of its oscillation in the withdrawal direction than twice the distance between the bobbin and yarn guide, on. The problems mentioned lead to variations in the yarn tension of the yarn, whereby the quality of a yarn processing process is impaired. In extreme cases, even thread breaks occur, resulting in increased stoppage of

Yarn processing machine leads. Accordingly, the withdrawal speed, that is, the speed at which the yarn is drawn off through the yarn guide, must be chosen so small that the problems mentioned are avoided.

The object of the invention is to provide a method and a device for extracting a yarn wound on a yarn package from above, which avoid the disadvantages of the prior art and with which, in particular, a homogeneous balloon is realized at an increased take-off speed.

This object is achieved by the method and apparatus of the independent claims. The dependent claims represent preferred embodiments of the invention. The method according to the invention for pulling off a yarn wound on a yarn package is based on the method steps:

- Providing the bobbin for over-head peeling in a Garnspulenaufnahme, and

- Pulling off the yarn from the yarn package through a yarn guide positioned in the yarn path of the yarn at a distance from the Garnspulenaufnahme. The yarn guide thus acts as a balloon breaker, i. the forming balloon can spread in the withdrawal direction only up to the yarn guide. According to the invention, the distance between the yarn guide and the yarn package receptacle is varied as a function of a controlled variable for optimizing the geometry of a balloon formed between the yarn package and the yarn guide by means of a yarn guide actuator device controlled by a control unit. The fact that the balloon crusher is adjustable in height above the yarn package by means of Garnführungsaktoreinrichtung, the ratio of the stroke length, ie the length of the yarn package, the distance between the balloon breaker and Garnspulenaufnahme can be varied.

With the method according to the invention, the shape of the balloon can be actively influenced since, depending on the distance between the balloon crusher and the yarn package receptacle, the damping of the yarn oscillation in the balloon is changed. The shape of the balloon has an influence on the thread tension of the yarn and vice versa. The average thread tension can be lowered significantly by the variation of the distance. It will be mainly

Thread tension peaks avoided, or their absolute height is reduced, which in addition has a smaller variation in the thread tension result. Depending on the type of yarn, the average yarn tension can be reduced by up to 40% with otherwise identical process parameters. This results in a possible increase in the take-off speed and thus in the production speed when using the method according to the invention in a yarn processing machine of up to more than 50%.

As a controlled variable, e.g. a time or run length-dependent desired distance in a desired distance storage element can be specified, or it can be determined as a controlled variable a current diameter of the yarn package by means of a diameter detection device, or it can be determined as a control variable a current weight of the yarn package by means of a weight detection device. The specification of a nominal distance can be made in particular when the yarn packages to be deducted are of uniform quality and the same quality. A measuring device for detecting the controlled variable can be dispensed with specification of such a desired distance. If the actual diameter or the current weight of the yarn package is used as the controlled variable, the increasing relative take-off speed can be compensated for as the amount of yarn on the yarn package decreases. For this purpose, the distance of the yarn guide is reduced to the yarn package. In particular, an arrangement with a focused light beam, e.g. a laser beam and a sensor.

Particularly preferably, at least one yarn tension of the yarn is determined as a controlled variable by means of a yarn tension sensor in the yarn path after the yarn guide. If at least one further thread tension is measured, eg at a different point in time, the variation of the distance can be carried out as a function of a thread tension tendency determined from the two thread tensions. This allows a direct control of the thread tension, which can also be considered by a changing winding quality occurring thread tension fluctuations. Preferably, a mean yarn tension over a time interval is measured as the yarn tension. As a result, short-term yarn tension maxima which are caused, for example, by smaller interference zones in the yarn winding on the yarn package or by the stroke of the yarn on the yarn package and do not significantly disturb the stability of the balloon, do not disturb the regulation of the distance.

Controlled controlled by the control unit is particularly advantageous, the distance varies such that by applying a control algorithm, a thread tension minimization is made. The control algorithm has the following method steps:

Measurement of the current yarn tension at a current distance of the yarn guide to Garnspulenaufnahme,

- Variation of the current distance by a distance increment to a new distance and measurement of a new thread tension at the new distance, and

- Apply the new distance as the actual distance, if the new thread tension is smaller than the current thread tension.

The sequence of steps is regularly repeated at certain intervals in order to minimize the yarn tension over the entire unwinding process. The distance is thus adjusted according to a yarn tension tendency, ie yarn tension change, with variation of the distance. A minimum withdrawal thread tension is basically achieved when an optimal balloon forms. When the thread tension is increased, disturbances of the balloon geometry can be directly observed. A minimization of the measured thread tension by a control algorithm therefore leads to the formation of an optimal balloon. The optimal balloon does not necessarily have to be a first-order balloon. With small yarn package diameters, the minimum yarn tension can also occur with a higher order balloon. Then the optimal balloon is the corresponding higher-order balloon and arises using the control algorithm automatically. For example, the length of thread from the point of departure to the balloon crusher can become too small for small bobbin diameters so that fluctuations due to the stroke are no longer properly compensated. In order to reduce the yarn tension maxima resulting from these fluctuations, a balloon of higher dimension can then be advantageous.

The behavior of the balloon depends e.g. of the yarn type, the winding type and the yarn package shape, i. of the type of sleeve on which the yarn is wound. Accordingly, a selection of the initial distance, i. the first actual distance, the pitch increment and / or the time interval in which the average thread tension is measured in each case and / or the time interval in which the yarn guide is in each case at the new distance are taken.

Different types of sleeves may e.g. cylindrical or conical shape and / or have different lengths and diameters. For example, For example, the pitch range at which an optimum balloon is formed is smaller with cylindrical yarn packages than with yarn packages having a conical shape, so that the spacing pitch is selected smaller for cylindrical yarn packages than at e.g. conical bobbins. The length of the yarn package, i. the stroke length of the yarn on the bobbin, and the type of winding, determine the balloon formation with respect to the disruption of the balloon caused by the stroke. It can follow that the decisive for the formation of an optimal balloon distance at a large stroke or winding-induced large thread tension fluctuations is relatively large, since a relatively large thread length should be available to compensate. The starting distance should then be greater.

In a particular embodiment of the method according to the invention, it may be advantageous to assign a starting distance as the actual distance, with an enlargement and a reduction of the distance taking place during the variation of the current distance and a new one in each case Thread tension is measured, and wherein when adopting the new distance, the distance at which the smallest thread tension was measured, is taken over as the current distance. As a result, the current distance can be reduced and increased to minimize the thread tension and thus obtain an optimal balloon.

A device according to the invention for extracting a yarn wound on a yarn package from above is set up to carry out the method according to the invention. The device according to the invention comprises: a yarn package receptacle arranged to provide the yarn package for pulling off the yarn overhead, and

- A positioned at a distance from Garnspulenaufnahme yarn guide, designed to guide the yarn when pulling off the head. Regelgrößenevorgabemittel provided are provided to provide at least one controlled variable to optimize the geometry of forming between the yarn package and the yarn guide balloon and there is provided a control unit, set the distance of the yarn guide to Garnspulenaufnahme depending on the controlled variable by means of Garnführungsaktoreinrichtung to vary.

The device according to the invention makes it possible to pull off overhead while providing the advantages of the method according to the invention.

Particularly preferably, a yarn tension sensor is arranged in a yarn path after the yarn guide, configured to determine at least one yarn tension of the yarn.

Alternatively, as the control quantity presetting means, a target distance storage element or a diameter detecting device or a weight detecting device may be provided. Preferably, the Garnführungsaktoreinrichtung on a rail slidable Garnführungshalterung, wherein an electric motor is provided, arranged to move the Garnführungshalterung on the rail. With such Garnführungsaktoreinrichtung a safe and stable variation of the distance of the yarn guide for Garnspulenaufnahme is possible.

The device according to the invention is suitable for use in yarn processing machines.

The invention will be explained in more detail by means of embodiments with reference to the drawings.

FIG. 1 shows a device according to the invention for extracting a yarn from above with a yarn tension sensor.

FIG. 2 shows a device according to the invention for extracting a yarn from above with a diameter-detecting device.

The figures of the drawings show the subject matter of the invention in a highly schematic manner and are not to scale. The single ones

Components of the article according to the invention are shown so that their construction can be well shown.

FIG. 1 shows a device according to the invention for pulling off overhead. In a Garnspulenaufnahme 2 a yarn package 3 is provided for overhead removal of the wound up thereon 4 yarn. The yarn package 3 consists of a sleeve of length LH, on which the yarn 4 is wound. The yarn 4 of the yarn package 3 is at one end by a yarn in the yarn run variable yarn guide 7 (balloon crusher), set up to guide the yarn 4 in overhead pulling off, carried out. The variable Yarn guide 7 is positioned in the region of an extension of the longitudinal axis 9 of the yarn package 3 above the yarn package 3 at a variable distance A from the yarn package receptacle 2. Characterized in that the distance to Garnspulenaufnahme 2 is variable, and the distance to the yarn package 3 is variable, because these distances differ only by a constant value. This variable yarn guide 7 is mounted on a Garnführungsaktoreinrichtung IO to change the distance A. When pulling off overhead, the symbolized by a dashed line balloon 12 forms between the variable yarn guide 7 and the respective deduction of the yarn 4 on the yarn package 3 from. The length of the balloon fluctuates between the value of the distance A and the value A plus LH due to the constantly changing withdrawal point during unwinding. The take-off speed of the yarn 3 and its direction are shown in the figure as arrow 13. In the further course of the yarn path of the yarn 4 after the variable yarn guide 7, a yarn tension sensor 16 is arranged. Between the yarn tension sensor 16 and the variable yarn guide 7, a further yarn guide 18 may be arranged, whereby the vibrations of the yarn 4 are continued to be attenuated by the balloon 12 via the variable yarn guide 7. The Garnführungsaktoreinrichtung 10 is controlled by a control unit 20, wherein the distance of the yarn guide 7 to Garnspulenaufnahme 2 is varied in response to a measured with the connected to the control unit yarn tension sensor 16 as a controlled variable 19 thread tension. This distance variation is symbolized by a double arrow 22 in the figure. The Garnführungsaktoreinrichtung 10 has a displaceable on a rail 25 Gamführungshalterung 26. By means of an electric motor 27, this Gamführungshalterung 26 is slidably controlled on the rail 25, whereby the distance of the variable yarn guide 7 is variable for Garnspulenaufnahme 2. The control unit 20, for example a microcomputer, is connected to the electric motor 27 for its control, for example via a cable 28. The control unit accepts measured thread tensions and is set up to execute a control algorithm, which is symbolized in the figure by the flowchart shown within the symbolically represented control unit 20. The control algorithm includes the following method steps:

Measurement of the current yarn tension at a current distance X of the yarn guide for yarn package receiving,

- Variation of the current distance by a distance increment DX to a new distance X minus DX and measurement of a new thread tension at the new distance, and

This will cause a thread tension minimization. The result is a homogeneous first-order balloon.

As the first current distance, e.g. the maximum with the Garnführungsaktoreinrichtung 10 adjustable distance can be selected. The pitch increment may be fixed or e.g. be chosen decreasing with decreasing distance. Furthermore, the thread tension measurement is carried out in a fixed time interval, so that a mean thread tension is measured. This time interval likewise determines the time in which the yarn guide actuator device 10 remains at least at a distance. This time interval can also be fixed or variable. Thus, the actual distance X is maintained until the mean value of the thread tension at a new distance X minus DX is smaller than at the current one, i. at the old distance.

FIG. 2 shows a device according to the invention for extracting a yarn from above with a diameter-detecting device 30. The

Diameter detecting device 30 replaces the yarn tension sensor of Figure 1. By means of the diameter detecting device 30, the actual diameter of the yarn package is measured and taken over by the control unit 20 as a controlled variable. In dependence on this controlled variable, the yarn guide 7 is moved between the positions PO and Pl by means of the motor 27. Proposed is a method and a device for the overhead removal of a wound on a yarn package 3 yarn 4. The method is based on the process steps:

- Providing the yarn package 3 for over-head peeling in a Garnspulenaufnahme 2, and

- Pulling off the yarn 4 from the yarn package 3 through a thread guide of the yarn 4 at a distance from the Garnspulenaufnahme 2 positioned yarn guide 7 through the top.

In doing so, e.g. by means of a yarn tension sensor 16 in the yarn path after the yarn guide 7 at least one yarn tension of the yarn 4 determined as a controlled variable 19 and by means of a 20 controlled by a control unit Garnführungsaktoreinrichtung 10, the distance of the yarn guide 7 to Garnspulenaufnahme 2 as a function of the controlled variable 19 varies.

The method is suitable for pulling the yarn from the yarn package at an increased speed.

The invention is not limited to the embodiments given above. Rather, a number of variants are conceivable, which make use of the features of the invention even with fundamentally different type of execution.

Claims

claims

1. Overhead method of drawing off a yarn (4) wound on a yarn package (3) with the method steps - Providing the yarn package (3) for pulling off in one head

Garnspulenaufnahme (2), and

pulling off the yarn (4) from the yarn package (3) through a yarn guide (7) positioned at a distance from the yarn package receptacle (2) in the yarn path of the yarn (4), characterized in that by means of a control unit (20) ) controlled Gamführungsaktoreinrichtung (10) the distance of the yarn guide (7) to Garnspulenaufnahme (2) in response to a controlled variable (19) for optimizing the geometry of between the yarn package (3) and the yarn guide (7) formed balloon (4) is varied ,

2. The method according to claim 1, characterized in that as a control variable (19) a time or run length-dependent desired distance is specified in a desired distance memory element, or that as

Controlled variable (19) a current diameter of the yarn package by means of a diameter detecting device (30) is determined, or that as a controlled variable (19) a current weight of the yarn package is determined by means of a weight detection device.

3. The method according to claim 1, characterized in that by means of a yarn tension sensor (16) in the yarn path after the yarn guide (7) at least one yarn tension of the yarn (4) is determined as a controlled variable (19).

4. The method according to claim 3, characterized in that a mean yarn tension over a time interval is measured as the yarn tension.

5. The method according to at least one of claims 3 to 4, characterized in that controlled by the control unit (20), the distance is varied such that by applying a control algorithm with the method steps:

- Measurement of the current thread tension at a current distance of the yarn guide (7) to Garnspulenaufnahme (2),

- Apply the new distance as the actual distance, if the new thread tension is less than the current thread tension, a thread tension minimization is made.

6. The method according to claim 5, characterized in that as the current distance, a starting distance is assigned, wherein in the variation of the current distance, an enlargement and a reduction of the distance is made and in each case a new thread tension is measured, wherein upon adoption of the new

Distance the distance at which the smallest thread tension was measured, is taken over as current distance.

7. A device for overhead removal of a on a yarn package (3) wound yarn (4), adapted for performing the method according to at least one of claims 1 to 6, comprising - a Garnspulenaufnahme (2), adapted to provide the

Bobbin spool (3) for removing the yarn (4) overhead, and - a yarn guide (7) positioned at a distance from the yarn package receptacle (2), arranged to guide the yarn (4) at the top, characterized in that

Regelgrößenevorgabemittel are provided, set up to provide at least one controlled variable (19) for optimizing the geometry of a between the yarn package (3) and the yarn guide (7) forming balloon (4) and a control unit (20) is provided, provided Distance of

Yarn guide (7) for Garnspulenaufnahme (2) as a function of the controlled variable (19) by means of Garnführungsaktoreinrichtung (10) to vary.

8. The device according to claim 7, characterized in that as Regelgrößenevorgabemittel a yarn tension sensor (16) in a yarn path after the yarn guide (7) is arranged to determine at least one yarn tension of the yarn (4) as a controlled variable (19), or as a rule size setting means

Sollabstandsspeicherelement or a diameter detecting device (30) or a weight detecting device are provided.

9. The device according to at least one of claims 7 to 8, characterized in that the Garnführungsaktoreinrichtung (10) on a rail (25) displaceable Garnführungshalterung (26), wherein an electric motor (27) is provided, the Garnführungshalterung

(26) to move on the rail (25).

10. Yarn processing machine with at least one device according to at least one of claims 7 to 9.