Technical field The invention relates to a method for winding yarn on a cross-wound bobbin on yarn manufacturing textile machines, in which yarn is drawn off from a production unit of a textile machine by a drawing-off mechanism at a constant speed and the bobbin being wound is in contact at its circumference with a driving roller. The invention also relates to a device for winding yarn on a cross-wound bobbin on yarn manufacturing textile machines comprising a plurality of workstations situated next to each other, whereby each workstation comprises a yarn production unit, from which yarn is drawn off by a drawing-off mechanism at a constant speed and is guided through a traversing device to a winding device comprising a driving roller, against which the bobbin being wound abuts at its circumference.

Background art

On yarn manufacturing textile machines yarn is produced in a yarn production unit, from which yarn is drawn off by a drawing-off mechanism, from which it is guided through a traversing device to a winding device, in which it is wound on a cross-wound bobbin. During the winding process the bobbin abuts against the circumference of a driving roller. The traversing device comprises a traversing guide mounted on a traversing rod, which is arranged reversibly displaceably along the length of the machine and its stroke width corresponds to the width of the package on the bobbin.

The device according to CZ 1997-2323 A3 derives the movement of a traversing rod through a cam mechanism. To reduce straining and wear of this mechanism and to enable increase in the speed of yarn winding, before the dead center of movement of the traversing rod are positioned springs which absorb the dynamic forces of the yarn and speed it up retroactively. The position of the springs with respect to the machine frame is a constant one, or it can be displaced according to the displacement of the outer dead centers of the traversing rod upon overlapping edges on the bobbin.

However, in the case of mechanical or pneumatic springs it is difficult to ensure their non-linear characteristics, which would meet requirements resulting from operational dynamics. Additional utilization of rubber or plastic bumpers acting on the traversing rod in the vicinity of dead centers causes impulses and vibration of the rod. Moreover, the service life of these elements is low. Due to loading, the service life of the springs themselves is also low.

The solution according to CZ 300588 B6 proposes to connect rotatably an end of a drawbar to a traversing rod, whose other end is rotatably connected to a rotatably mounted main crank. The crank constitutes an output means of a rotary electronically controllable drive coupled to a driving mechanism. The main crank together with the electronically controllable drive is connected to the textile machine frame through a displaceable coupling to ensure overlapping of the yarn package in dead centers, the so-called blurring.

The angular speed of the main crank is continuously decreased or increased by means of the rotary electronically controllable drive controlled by a control mechanism upon movement of the traversing element from one dead center to another. This has a direct dependence on the required magnitude of the angle of the yarn crossing on the bobbin being wound and/or a direct dependence on the position of the traversing element, through which the required angle of the yarn crossing on the bobbin being wound and/or the required course of the speed of movement of the traversing element is achieved.

The function of such a device may satisfactorily meet the requirements for a high-quality arrangement of the package, thereby also contributing to solving problems of inertia forces generated by the reciprocating movement of the traversing rod. On the other hand, the drawback is the dynamic stress of the traversing rod, which limits the maximum speed of yarn winding. This is a shortcoming of all systems with a central traversing system by means of a traversing rod. In order to eliminate band windings in these machines, a periodic variation in the speed of the drive of the traversing rod is used and in order to blur the edges of the package within specified limits, the stroke width of the traversing rod varies within specified limits or the traversing rod slightly reciprocates at a constant stroke.

For high winding speeds, individual traversing at each workstation is currently used, for example by means of wings or bands. Nevertheless, these traversing devices are relatively complex and expensive and as the machine comprises a plurality of workstations, the price of the machine significantly increases.

All the above-mentioned systems include a yarn guide, which due to inertial forces during stopping and acceleration in the opposite direction negatively affects the function of the traversing device in dead centers even at a low weight of the yarn guide.

On winding machines, on which the produced yarn is wound from a cop onto a cross-wound bobbin, yarn is traversed by a traversing roller provided with a traversing groove. The traversing roller is at each workstation coupled to an individual drive. At the same time, the traversing roller serves as a drive for the bobbin, which during winding abuts against its circumference. During traversing, the yarn is guided along the groove of the traversing roller, and so it is not acted upon by any mass element, such as a traversing guide, and therefore it is traversing of yarn with using grooved drum. Band windings in winding machines are eliminated by a periodical step change in the speed of the traversing roller, whereby due to the inertial forces from the bobbin package slip occurs between the surface of the bobbin being spooled and the surface of the traversing roller, which causes elimination of the band windings, but also a change in the winding speed. This is the reason why this system of traversing cannot be used on yarn manufacturing machines, in which the rate of delivery of the yarn from the production unit is substantially constant.

The goal of the invention is to propose a technically simple and economically undemanding method for traversing, which enables on yarn manufacturing textile machines to wind yarn on a cross-wound bobbin at several-fold higher speeds with the option of selecting the angle of crossing the yarn wound onto a bobbin, whereby this method allows to easily eliminate band windings and blurring the edges of the bobbin being wound. In addition, the goal of the invention is to provide a device which would be able to perform this method.

Principle of the invention The aim of the invention is achieved by a method for traversing yarn according to the invention, whose principle consists in that yarn for traversing is guided only by a traversing groove formed along the circumference of a traversing roller forcedly rotating separately from a driving roller of a bobbin and separately from the bobbin being wound. The bobbin being wound is in contact only with the driving roller. Due to separating the drive of the bobbin and the traversing of the yarn it is possible to use the traversing roller with the groove for traversing yarn also on yarn manufacturing textile machines, wherein the yarn for traversing is fed at a constant speed. The system of traversing with a traversing roller results in a several-fold increase in the speed, as shown on winding machines. Unlike them, the drive of the individual traversing rollers is central.

For obtaining the required shape of the package, the length of the yarn portion between the traversing groove and the point of winding yarn on the bobbin and/or the gap size between the surface of the traversing roller and the surface of the bobbin being wound is controlled.

The length of the yarn portion between the traversing groove and the point of winding yarn on the bobbin affects the shape of the package. In order to obtain a biconical package, with the faces of the bobbin becoming narrower in the upward direction, the length of the yarn portion between the traversing groove and the point of winding the yarn on the bobbin grows with the increasing diameter of the bobbin.

To obtain fiat faces of the bobbin, the length of the yarn portion between the traversing groove and the point of winding the yarn is maintained constant.

Similarly, the gap size between the traversing roller of a workstation and a respective bobbin being wound is essential for maintaining the selected shape of the package. The principle of the device for winding yarn on a cross-wound bobbin consists in that the traversing device of a workstation comprises a traversing roller provided along its circumference with a traversing groove. The circumference of the traversing roller is out of contact with the bobbin being wound and the driving roller of the bobbin. The device eliminates the dynamic stress and strain generated in the current traversing systems on yarn manufacturing textile machines and enables to achieve further increase in the speed of the actually produced yarn.

For easy and accurate handling, the bobbin is mounted in bobbin arms of a bobbin frame, which is slidingly reversibly displaceably arranged on a guiding means disposed on the machine frame.

In particular, the guiding means may be linear, arc or curvilinear, according to the required package shape.

The traversing roller is mounted on a traversing shaft, which is common to the traversing rollers of all the workstations along one side of the machine and is coupled to a rotary drive. For blurring edges in a package the traversing shaft is mounted with the option of axial movement and is coupled to means for actuating its reversible axial movement within a predetermined range.

For the purpose of compensating for the yarn length during traversing, a traversing groove with small diameter faces is provided on an imaginary barrellike surface, instead of the usual rigid convex guides. This is achieved either by a traversing groove having a constant depth formed in a barrel-like traversing roller, or by a traversing groove having a varying depth formed in a traversing roller of cylindrical shape.

Description of drawings

The method and device according to the invention will be explained with reference to the drawings, wherein Fig. 1 represents a diagram of a winding device according to the invention, Fig. 2 shows a biconical package, Fig. 3 shows an arrangement of traversing rollers on a common traversing shaft and illustrates the influence of the gap between the winding roller and the bobbin on the width of the yarn package on the bobbin, Fig. 4 shows a barrel-like winding roller, Fig. 5 is a view of the winding device in a model embodiment for one workstation, Fig. 6 represents a diagram illustrating the dependence of the length of the yarn portion between the traversing groove of the traversing roller and the point of winding the yarn on the bobbin on the diameter of the bobbin being wound in the case of a biconical package, Fig. 7 is a diagram representing the dependence of the gap between the traversing roller and the bobbin being wound on the bobbin diameter in the case of a biconical package.

Examples of embodiment

A yarn manufacturing textile machine, such as an open-end spinning machine, comprises a plurality of workstations situated next to each other, whereby each of them has a well-known unillustrated yarn production unit, from which the yarn is drawn off by a well-known drawing-off mechanism II, which comprises a drawing-off roller 1 1 driven at a constant speed and a pressure roller 12, which is tiltable from it. From the drawing-off mechanism 1 the produced yarn 2 is guided through a traversing device to a winding device 3, in which it is wound on a cross-wound bobbin 4. In some embodiments of yarn manufacturing machines the drawing-off roller 1 1 is coupled to an individual drive and in that case the draw-off speed of yarn may vary, for example when resuming spinning.

The winding device 3 comprises a driving roller 31_, against which a bobbin 4 abuts with its surface during winding, the bobbin being mounted between arms 321 of a bobbin frame 32, which is in the embodiment illustrated in Figs. 1 and 5 mounted in a linear guiding means 5 arranged on the machine frame. In an unillustrated alternative embodiment, the guiding means 5 is arc or curvilinear. The bobbin frame 32 is coupled to a pressure means 322, serving to maintain contact and sufficient pressure between the surface of the bobbin 4 and the driving roller 31 during winding at each respective workstation. The driving roller 31 is mounted on a driving shaft 6, which is common to the driving rollers 31 of all the workstations along one side of the machine and is coupled to a well-known unillustrated drive. At each workstation, the traversing device comprises a traversing roller 7 , which is provided with a traversing groov7e1 , just as is the case with winding machines. The traversing roller 7 is out of contact with the bobbin 4 being wound and the driving roller 31. of the bobbin 4 is mounted on a traversing shaft 8, which is common to the traversing rollers 7 of all the workstations along one side of the machine and is coupled to a well-known unillustrated rotary drive.

Between the drawing-off mechanism 1 and the winding device 3 is arranged a well-known compensator 9 of the additional winding speed of the yarn 2 being wound, which arises in the course of winding the bobbin 4 during transition between dead centers of the package. The compensator 9 is shown only in Fig. 1 , which does not show the drawing-off mechanism 1_, which is shown only in Fig. 5.

As is schematically represented in Fig. 1 , the yarn 2 delivered at a constant speed by the drawing-off mechanism 1 is guided to the traversing groove71 of the traversing roller 7 , along which it is traversed due to the rotation of the traversing roller 7 along the entire width of the package of the bobbin 4, on which it is wound due to the bobbin rotation. The traversing roller 7 is arranged out of contact with the bobbin 4 being wound, as well as out of contact with the driving roller 31 , with which only the bobbin 4 being wound is in contact. Owing to the fact that no mass element (yarn guide) moving reversibly along the width of the package takes part in the process of traversing the yarn 2, it is the so-called traversing of yarn only with using grooved drum formed in the traversing roller 7.

In this arrangement, it is possible to eliminate band windings on the bobbin 4 within a selected range by a slow programmatical and cyclical change in the rotational speed of the traversing roller 7 , independently of the rotational speed of the driving roller 31. Also, it is possible to change the angle of crossing the yarn 2 being wound on the bobbin 4 by an overall change in the rotational speed of the traversing roller 7, independently of the rotational speed of the driving roller 31.

The traversing shaft 8 is mounted in the machine with the option of axial movement within a predetermined range, which is not shown in the drawings, for the so-called blurring the edges of the package and for that purpose it is coupled to means for actuating its reversible axial movement, for example to a cam mechanism.

The principle of the method according to the invention is traversing yarn 2 only with using grooved drum along the entire width of the yarn 2 package on the bobbin 4, which is made possible by using a traversing roller 7 only for traversing the yarn 7 and not for driving the bobbin 4, as is the case with winding machines, and providing the drive of the bobbin 4 by means of a separate driving roller 31, which is in contact with the bobbin 4 being wound. It is important to note that the length of the yarn 2 portion between the traversing groove71 of the traversing roller 7 and the point of winding the yarn 2 on the bobbin 4 and/or the gap size between the traversing roller 7 and the bobbin 4 being wound is/are controlled.

The length of the yarn 4 portion between the traversing groove71 and the point of winding the yarn 2 on the bobbin 4 affects the shape of the package. To obtain a biconical package, when the faces of the bobbin become narrower in the upward direction, as is shown in Fig. 2, the length of the yarn 2 portion between the traversing groove71 and the point of winding yarn 2 on the bobbin 4 increases with the increasing diameter of the bobbin 4.

To obtain flat faces of the bobbin 4, the length of the yarn 2 portion between the traversing groove 71 and the point of winding yarn 2 is maintained constant.

A diagram of dependence of the length of the yarn 2 portion between the traversing groove71 and the point of winding the yarn 2 on the bobbin 4 in mm on the diameter of the bobbin 4 being wound in mm for a biconical package is shown in Fig. 6.

Similarly, the gap size between the surface of the traversing roller 7 of a workstation and the surface of a respective bobbin 4 being wound contributes to maintaining the specific shape of the package, whereby the gap is either maintained constant, or it increases during winding. The influence of the size of the gap between the traversing roller 7 and a respective bobbin 4 being wound, as well as the influence of the length of the yarn 2 portion between the traversing groove71 of the traversing roller 7 and the point of winding the yarn 2 on the bobbin 4 is illustrated in Fig. 3, which shows two workstations which have traversing rollers 7 with traversing grooves \_ having the same stroke L. The axis of the bobbin 4 being wound on the left is situated at a distance hi from the axis of the traversing rollers 7. The axis of the bobbin 4 being wound on the right is situated at a distance g from the axis of the traversing rollers 7. Owing to the fact that is greater than also the gap between the traversing roller 7 and the bobbin being wound 4 on the right is greater. At the same time, also the length of the yarn portion between the traversing groove71 and the point of winding yarn 2 on the bobbin on the right is greater while maintaining the same angle of crossing a. The width S_2 of the bobbin on the right is therefore smaller than the width Si of the package on the bobbin on the left.

The diagram of the dependence of the size of the gap between the traversing roller 7 of a workstation and a respective bobbin 4 being wound in mm on the diameter of the bobbin being wound in mm for a biconical package is shown in Fig. 7.

Industrial applicability

The invention is applicable on spindle-less spinning machines, especially on open-end spinning machines.

List of references

1 drawing-off mechanism of yarn

11 drawing-off roller

12 pressure roller

2 yarn

3 winding device

31 driving roller

32 bobbin frame

321 arms of bobbin frame

322 pressure means of bobbin frame

4 bobbin

5 guiding means

6 driving shaft of driving rollers

7 traversing roller

71 traversing groove

8 traversing shaft