ROTOR SPINNING MACHINE AND METHOD FOR OPERATING A ROTOR SPINNING MACHINE

Abstract

The invention relates to a rotor spinning machine and to a method for operating a rotor spinning machine with a control device, an open-end rotor spinning device and a supply unit feeding at least two fiber slivers into the open-end rotor spinning device, which supply unit has an opening roller for opening fiber slivers and a feed apparatus with a first and a second feed roller, which can be operated independently of one another by means of the control device, for a first fiber sliver and a second fiber sliver. In order to provide a rotor spinning machine as well as a method for operating a rotor spinning machine, which enables easy setting of the drafting speeds of the supply unit having at least two feed rollers, it is provided that the control device determines an individual drafting speed of one feed roller for producing a yarn with predetermined yarn properties from a single fiber sliver fed by means of the first feed roller, and coordinates a first drafting speed of the first feed roller and a second drafting speed of the second feed roller with one another in such a way that the sum of the first and second drafting speeds corresponds to the individual drafting speed.

Description

The invention relates to a rotor spinning machine and to a method for operating a rotor spinning machine with a control device, an open-end rotor spinning device and a supply unit which feeds at least two fiber slivers into the open-end rotor spinning device and has

• • an opening roller for opening fiber slivers and
  • a feed apparatus having a first and a second feed roller, which can be operated independently of one another by means of the control device, for a first fiber sliver and a second fiber sliver. Rotor spinning machines with two feed rollers or feed roller sections, which can be operated independently of one another, of a single feed roller, and methods for the operation thereof are known in a variety of embodiments from the prior art.

Rotor spinning machines of this kind enable the feeding of two different or two identical spinning materials into the open-end rotor spinning device, whereby, for example, so-called effect yarns can be produced, which have, for example, a thickness variation or color variations.

The determination of the spinning parameters such as the thread draw-off speed, the rotor rotational speed and the first and second drafting speeds of the first and second feed rollers for producing a uniform yarn with predetermined yarn parameters is possible only with considerable effort.

Proceeding from this, the object of the invention is to provide a rotor spinning machine and a method for operating a rotor spinning machine, which enables easy setting of the drafting speeds of the supply unit having at least two feed rollers.

The invention achieves the object by a method for operating a rotor spinning machine with the features of claim 1 as well as by a rotor spinning machine with the features of claim 5. Advantageous further embodiments of the invention are given in the dependent claims.

According to the method according to the invention, it is provided that first of all, the control device, after specifying the yarn properties of the yarn to be produced, e.g. by the operating personnel inputting the yarn parameters via an operating unit, determines the individual drafting speed which would be required for producing the specified yarn by means of only one feed roller feeding only one single fiber sliver to the open-end rotor spinning device. The individual drafting speed is accordingly the drafting speed which would be required to produce a specified yarn using a supply unit having only one feed roller.

This individual drafting speed is used as a basis in the control device for setting the first drafting speed of the first feed roller and the second drafting speed of the second feed roller, namely in such a way that the control device matches the first drafting speed and the second drafting speed to one another in such a way that their sum corresponds to the previously determined individual drafting speed. When there is a change in the first drafting speed, which is performed by the operator, for example, the control unit automatically adjusts the second drafting speed so that the sum of the first and second drafting speeds again corresponds to the previously determined individual drafting speed. The operating personnel accordingly have the possibility of adapting the share of the fiber slivers supplied to the open-end rotor spinning device without irregularities occurring in the yarn to be produced. In addition, when two identical fiber slivers are supplied, mass fluctuations in the spun fiber mass are prevented, so that a continuously uniform yarn can be produced.

The method according to the invention is characterized in that the spinning parameters, in particular the individual drafting speed, can be easily and reliably determined in a familiar way. This individual drafting speed is based on the operation of the supply unit with at least two feed rollers, wherein the relationship of the drafting speeds of the individual feed rollers is matched to one another by the control device in such a way that together, they correspond to 100% of the individual drafting speed. An increase in the drafting speed of the first feed roller leads to a reduction in the drafting speed of the second feed roller in a supply unit having two feed rollers. The relationship of the drafting speeds to one another represents a further spinning parameter which, for example, can be set by the operating personnel via an operating unit connected to the control device.

The number of underlying yarn parameters for determining individual drafting speed can be freely selected in principle. According to a particularly advantageous embodiment of the invention, however, it is provided that the control device for determining the individual drafting speed detects the rotation, the draft and/or the yarn number of the yarn to be produced. Considering a plurality of yarn parameters makes it possible, by means of the control device, to determine the spinning parameters, for example the rotor rotational speed representing the reference variable, and the speed of the thread take-off and the individual drafting speed in a particularly precise manner as the basis for setting the drafting speed of the first and second feed rollers.

According to a further embodiment of the invention, it is provided that the control device further detects the fiber sliver numbers of the fiber slivers to be fed in, which increases, in a complementary way, the quality of the yarn to be produced.

The determination of the individual drafting speed on the basis of the predetermined yarn properties can in principle be performed in any desired manner. According to a particularly advantageous embodiment of the invention, however, it is provided that the control device calculates the individual drafting speed on the basis of the predetermined yarn properties, or retrieves it from a database. The individual drafting speed can be reliably determined in a simple manner with proven methods. There are also sufficient data for determining the individual drafting speed, i.e. of the supply unit having only one feed roller, so that such data can be easily retrievably provided in database.

Characteristic of the rotor spinning machine according to the invention is that the control device is designed to determine an individual drafting speed of one feed roller for producing a yarn with predetermined yarn properties from only one single fiber sliver supplied by means of the only one feed roller. Based on this individual drafting speed, the control device is further configured to set a first drafting speed of the first feed roller and a second drafting speed of the second feed roller in such a way that the sum of the first and second drafting speeds corresponds to the individual drafting speed.

The rotor spinning machine according to the invention is characterized by the fact that the individual drafting speed required for producing the specified yarn can be determined in a particularly simple manner by means of the control device. This is based on the setting of the drafting speed of the individual feed rollers in the control device, wherein the control device adjusts the drafting speeds to one another in such a way that their sum corresponds to the individual drafting speed. Adaptations of one of the drafting speeds of the feed rollers, for example by the operating personnel, accordingly lead in an automated manner by the control device to a corresponding adaptation of the drafting speed of the other feed roller in such a way that the sum of the drafting speeds corresponds to the individual drafting speed previously determined by the control device.

The rotor spinning machine according to the invention accordingly allows the operating personnel to carry out adjustments of the fiber sliver feed in a particularly simple manner, without the uniformity of the yarn to be produced being influenced thereby.

According to a development of the invention, it is provided that the control device is connected to an operating device for data input. The operating unit thus enables the operating personnel to conveniently enter the yarn parameters of the yarn to be produced so that the spinning parameters can be determined by the control device. The operating unit also makes it possible to adjust the speed of the individual feed rollers by the machine operator, wherein a corresponding adaptation of the unadapted feed roller is then performed automatically by the control device.

In order to determine the individual drafting speed, the control device is connected to a computing unit and/or a database. The computing unit enables the computational determination of the individual drafting speeds in a known and proven manner. The use of a database allows the control device to alternatively or additionally query the spinning parameters based on the yarn parameters of the yarn to be produced.

The invention is explained below with reference to the drawings. In the drawings:

FIG. 1 shows a perspective view of an open-end rotor spinning machine having a plurality of workstations and

FIG. 2 shows a schematic view of a supply unit having two feed rollers.

FIG. 1 shows a perspective view of an exemplary embodiment of a rotor spinning machine 1 with a central control unit 8 which is equipped with a control device 9 designed according to the invention. Rotor spinning machines are known to have a plurality of workstations 2 which are each equipped with an open-end rotor spinning device 3 and a winding device 4, among other things. For feeding fibers into the open-end rotor spinning device 3, the individual workstations 2 each have a supply unit 11 which is shown below in FIG. 2.

The workstations 2 of the rotor spinning machine 1 are supplied by service units 5. These serve, for example, to exchange a finished cross-wound bobbin 7 against a fresh empty bobbin at the workstations 2.

As is known and therefore not explained in detail, in the open-end rotor spinning devices 3 of the working stations 2 of the rotor spinning machine 1, two fiber slivers 12, 13 which are stored in spin cans 6 as well as on bobbins 27 are spun into a yarn with predetermined yarn properties, which are subsequently wound into packages on the winding devices 4. For controlling the rotor spinning machine 1 and the individual workstations 2, the rotor spinning machine 1 has the central control unit 8 which is equipped with a control device 9 designed according to the invention. Via an operating unit 10, it is possible for the system operator to enter yarn parameters of the yarn to be produced and to read and modify spinning parameters.

The control device 9 also serves to control the supply unit 11 schematically shown in FIG. 2 for feeding fibers from at least two fiber slivers 12, 13 into the open-end rotor spinning device 3. In this case, the supply unit 11 has two feed rollers 16, 17, which can be driven separately from one another by the control device 9, for supplying fiber slivers 12, 13 and an opening roller 14 for separating the fiber slivers 12, 13 into individual fibers. The axis of rotation 15 of the feed rollers 16, 17 and the axis of rotation (not shown) of the opening roller 14, shown only sectionally, run parallel to one another.

The feed rollers 16, 17 have a first roller section 18 and a second roller section 19 which are each provided for supplying a fiber sliver 12, 13. Both roller sections 18, 19 are formed identically to one another and in particular have an identical shape and size. In order to better transport the supplied fiber sliver 12, 13, both roller sections 18, 19 each have a linear profile.

The first feed roller 16 and the second feed roller 17 can be driven separately from one another via drives (not shown here) via the control device 9. To determine the drafting speeds of the first feed roller 16 and the second feed roller 17, the control device 9 first detects yarn parameters of a yarn to be produced, in particular the draft, the twist, the yarn number and the fiber sliver number of a fiber sliver to be supplied. On the basis of this, the control device 9 determines the necessary individual drafting speed of the individual feed roller 16, 17 for the case of a supply unit 11 having only one feed roller 16, 17 for supplying a fiber sliver 12, 13. This individual drafting speed serves the control unit 9 as a reference variable for controlling the two feed rollers 16, 17 of the supply unit 11. The sum of the drafting speeds of the two feed rollers 16, 17 corresponds to the individual drafting speed previously determined by the control device 9. In the relationship in which the drafting speed of a feed roller 16, 17 is lowered or increased by the operating personnel, the control device 9 increases or lowers the drafting speed of the other feed roller 16, 17.

In order to ensure a safe supply of the fiber slivers 12, 13 to the feed rollers 16, 17 and a reliable transport by means of the feed rollers 16, 17, a guide element 20 with a supply section 21 is arranged in the feed direction of the feed rollers 16, 17, wherein the feed section 21 is formed flat and has a feed trough 22 opposite the feed rollers 16, 17 and lowered into the plane of the feed section 21. Between the feed trough 22 and the feed rollers 16, 17, there is a gap 23 in which the fiber slivers 12, 13 are transported to the rotating feed rollers 16, 17.

A guide housing 24 is arranged in the feed section 21 directly upstream of the feed rollers 16, 17 and surrounds each of the two fiber slivers 12, 13 supplied to one of the roller sections 18, 19 on three sides, so that a closed guide tunnel 25, 26 for each of the two fiber slivers 12, 13 is formed as a fourth side together with the flat surface of the feed section 21. The first guide tunnel 25 is longer than the second guide tunnel 26, so that the first fiber sliver 12 supplied from a spinning edge 6 from the underside of the guide element 20 cannot come into contact with the second fiber sliver 13 supplied from a coil 27 by the upper side of the guide element 20, as a result of which a completely independent supply of both fiber slivers 12, 13 is achieved.

Finally, the integrally formed guide element 20 has an opening roller section 28 which follows the feed trough 22 and extends sectionally along the direction of rotation of the opening roller 14 at a constant distance along the surface of the opening roller 14. The gap formed between the opening roller section 28 and the surface of the opening roller 14 ensures that the fiber slivers 12, 13 fed from the feed rollers 16, 17 are reliably separated into individual fibers at the surface of the opening roller 14.

LIST OF REFERENCE SIGNS

• 1 Rotor spinning machine
• 2 Workstations
• 3 Open-end rotor spinning device
• 4 Coil device
• 5 Service unit
• 6 Spin can
• 7 Cross-wound bobbin
• 8 Central control unit
• 9 Control device
• 10 Operating unit
• 11 Supply unit
• 12 Fiber sliver
• 13 Fiber sliver
• 14 Opening roller
• 15 Axis of rotation
• 16 Feed roller
• 17 Feed roller
• 18 First roller section
• 19 Second roller section
• 20 Guide element
• 21 Feed section
• 22 Feed trough
• 23 Gap
• 24 Guide housing
• 25 Guide tunnel
• 26 Guide tunnel
• 27 Coil
• 28 Opening roller section

Claims

1. A method for operating a rotor spinning machine (1) with a control device (9), an open-end rotor spinning device (3) and a supply unit (11) that feeds at least two fiber slivers (12, 13) into the open-end rotor spinning device (3) and has

an opening roller (14) for opening fiber slivers (12, 13) and

a feed apparatus having a first and a second feed roller (16, 17), which can be operated independently of one another by means of the control device (9), for a first fiber sliver (12) and a second fiber sliver (13),

characterized in that

the control device (9)

determines an individual drafting speed of one feed roller (16, 17) which would be required to produce a yarn with predetermined yarn properties from a single fiber sliver (12, 13) fed by means of the one feed roller (16, 17) and

coordinates a first drafting speed of the first feed roller (16) and a second drafting speed of the second feed roller (17) with one another in such a way that the sum of the first and second drafting speeds corresponds to the individual drafting speed.

2. The method according to claim 1, characterized in that the control device (9) detects the twist, the draft and/or the yarn number of the yarn to be produced in order to determine the individual drafting speed.

3. The method according to claim 1, characterized in that the control device (9) detects the fiber sliver numbers of the fiber slivers (12, 13) to be fed in.

4. The method according to claim 1, characterized in that the control device (9) calculates the individual drafting speed on the basis of the predetermined yarn properties or retrieves it from a database.

5. A rotor spinning machine (1) with a control device (9), an open-end rotor spinning device (3) and a supply unit (11) that feeds at least two fiber slivers (12, 13) into the open-end rotor spinning device (3) and has

an opening roller (14) for opening fiber slivers (12, 13) and

a feed apparatus having a first and a second feed roller (16, 17), which can be operated independently of one another by means of the control device (9), for a first fiber sliver (12) and a second fiber sliver (13),

characterized in that

the control device (9) is designed

to determine an individual drafting speed of one feed roller (16, 17) which would be required to produce a yarn with predetermined yarn properties from a single fiber sliver (12, 13) fed by means of the one feed roller (16, 17) and

to set a first drafting speed of the first feed roller (16) and a second drafting speed of the second feed roller (17) such that the sum of the first and second drafting speeds corresponds to the individual drafting speed.

6. The rotor spinning machine (1) according to claim 5, characterized in that the control device (9) is connected to an operating unit (10) for data input.

7. The rotor spinning machine (1) according to claim 5, characterized in that the control device (9) is connected to a computing unit and/or a database.