EP3115486B1 - Stretching unit with multiple fibre band guides - Google Patents

Description

The present invention relates to a drafting device for drawing a sliver, with at least three in the direction of the sliver successively arranged pairs of rollers. The pairs of rollers each comprise at least one lower roller and at least one upper roller, wherein the sliver is passed between each pair of rollers. Furthermore, the drafting system has at least one sliver guide, by means of which the sliver is guided, wherein at least a first sliver guide is arranged in the running direction of the sliver before the drafting and at least one second sliver guide in the running direction of the sliver after the drafting.

At present, the drafting units in operation comprise a fleece funnel which is arranged after the roller pairs. The fleece funnel grips the spread fiber sliver into a fiber bundle having an approximately round cross-section, so that the fiber bundle can be gently deposited in a jug and present in a suitable form for further processing. In addition, the drafting systems comprise a guide arranged in front of the roller pairs, which comprises two surfaces, wherein the surfaces limit the fiber band in a width and introduce the sliver in the drafting system. In particular, the surfaces bound the sliver such that it passes completely between the roller pairs.

From the CH 697 916 B1 For example, a drafting system with at least three roller pairs is known, which comprises a fleece funnel, which is arranged after a pair of output rollers. By means of the fleece straightener, a spread nonwoven ribbon is combined to form a sliver having a substantially round cross section.

From the DE 10 2008 049 363 A1 is also shown a drafting system with at least three pairs of rollers. The drafting system further comprises a guide element arranged in front of the roller pairs, which can have baffles.

In the EP 2 199 439 A2 a compressor unit and a traversing device for a drafting system of a textile machine are described. The compressor unit contains at least one compression channel for a completely distorted fiber structure and at least one means for coupling the compressor unit to a traversing roller movable along the traverse rollers. The compressor unit contains at least one guide surface for a fiber strand in the main draft zone. The traversing device includes an element for coupling the traversing device to a non-displaceable rail running parallel to the drafting rollers and a connecting arm for coupling the compressor unit. The connecting arm is connected to at least one inlet compressor and to at least one pre-draft compressor.

From the US 3,007,211 A For example, a fiber guide roll and a fiber compressor are known. The fiber compressor has a funnel section, which is rotatably mounted relative to the fiber guide roller and spaced therefrom. Through the hopper section, a sliver is passed, which is guided by the rotating fiber guide roller.

From the CH 359 073 A a device for consolidating a sliver in spinning machines is known. The apparatus comprises a funnel which feeds the sliver to a sliver can and which is stepped at least once inside between a conical and a cylindrical part.

From the US 2,187,830 A For example, a delay mechanism for reducing a cross-section of a sliver is known. Between two pair of drafting rollers a guide is arranged, which summarizes the sliver.

From the JP 2009 030180 A For example, a compressor is known which comprises a funnel arrangement. The funnel arrangement comprises two spaced-apart surfaces which can be pushed toward and away from one another by means of a lever, so that their spacing can be changed manually.

From the WO 2014/057324 A1 is a drafting for stretching a drafting material supplied to the pulp known, the drafting system has at least three successively arranged pairs of rollers. The drafting device further comprises at least two shielding elements, which are arranged in a region in front of a pair of rollers and have a distance that the fiber mass is guided laterally. The shielding elements each close with their, the pair of rollers facing ends, directly to the peripheral surfaces of the roller pair.

A disadvantage of the prior art is that the sliver is performed insufficiently in the area immediately before and / or between the roller pairs. Just between the pairs of rollers can lead to an unclean guidance of the sliver by an acceleration of the drawing produced by the different rotational speeds of the pairs of rollers. As a result, the quality of the sliver is impaired because the sliver in the drafting can perform a lateral movement, which can lead to a different in the width of the sliver stretching.

Object of the present invention is therefore to provide a drafting system by means of which the sliver is guided laterally in the drafting, so that a uniform stretching is formed.

The object is achieved by a drafting system with the features of the independent claim.

Proposed is a drafting system for stretching a sliver, with at least three in the direction of the sliver successively arranged pairs of rollers. Each pair of rollers comprises at least one lower and at least one upper roller, wherein the sliver is passed between each pair of rollers. The lower and upper rollers are cylindrical and their axial axes can be arranged parallel to each other. Each pair of rollers also has a nip line which is formed at the contact points of the lower and upper rollers and extending in the axial direction on the lateral surfaces of the lower and upper rollers. Between these nip lines, the sliver is passed, so that upon rotation of the pairs of rollers, the sliver is entrained.

In the direction of the fiber sliver, the first pair of rollers may be referred to as an input roller pair, the second pair of rollers as an intermediate roller pair and the third pair of rollers as the output roller pair. In order to produce the stretching of the fiber sliver, the three pairs of rollers have a different, in particular one of the pair of input rollers to the pair of output rollers rising, rotational speed. As a result, a first drawing zone is formed between the pair of input rolls and the intermediate roll pair, and a second drawing zone is formed between the pair of intermediate rolls and the pair of delivery rolls. For example, the rotational speed of the intermediate roller pair is twice greater than the rotational speed of the input roller pair, so that the sliver in the first drawing zone is stretched by a factor of two. In addition, the output roller pair may have a rotational speed that is three times greater than the rotational speed of the intermediate roller pair, so that the sliver in the second drawing zone is stretched by a factor of three. The sliver is thus stretched in the drafting system by a factor of six. The rotational speeds can be varied in order to adapt the drawing factor to special requirements.

Furthermore, the drafting system comprises at least one sliver guide, by means of which the sliver is guided, wherein at least one first sliver guide in the direction of the sliver before the drafting and at least one second sliver guide in the direction of the sliver are arranged after the drafting.

Further, a third sliver guide is arranged between two pairs of rollers, so that the sliver is guided laterally. Additionally or alternatively, the third sliver guide can also be arranged in the running direction of the sliver in front of a first pair of rollers, in particular in front of the pair of input rollers. This can be prevented that in a sliver having a width which is comparable to a width of the roller pairs, the sliver slips laterally from the areas of the lateral surface of the rollers in the region of an end face of the rollers. In these areas, the sliver is no longer stretched because it is no longer properly pulled along and / or accelerated by the nip so that irregularities occur in the sliver. In addition, there is a risk that parts of the sliver are completely detached from the sliver and settle in the drafting system, which can hinder the functioning of the drafting and affects the sliver in its quality. The third sliver guide thus guides the sliver safely between the pairs of rollers.

According to the invention, the first sliver guide, which is arranged in the running direction of the sliver in front of the drafting system, comprises the sliver guide. The tape guide is formed as an elongate base body with two guide surfaces, wherein the guide surfaces are arranged helically on the base body. Furthermore, the helixes formed in this way can be arranged so that a distance between the two guide surfaces becomes continuously smaller. In addition, the main body of the tape guide can be rotated so that the sliver passes through the tape guide in places where the distance between the two helical Fins is smaller or larger. As a result, the sliver is compressed correspondingly less or more in a transverse direction to the running direction.

An advantageous development of the invention is when the drafting system comprises sensors, by means of which a position and / or the stretching of the sliver can be detected. The position of the sliver can be registered, for example, by means of one or more light barriers at different points in the drafting system. The stretching can be measured, for example, by means of electromagnetic sensors and / or by means of at least one calender roller pair. During the stretching, for example, the thickness of the sliver is measured and from this the drawing is calculated.

Furthermore, the drafting device advantageously comprises a control unit, by means of which data can be evaluated by the sensors. The data include the position and / or the stretching of the sliver. The control unit comprises for this purpose a computing unit, a memory unit and is connected to the sensors. Thus, for example, the stretching can be logged, so that the quality of the sliver can be evaluated later.

It is likewise advantageous if the drafting arrangement comprises actuators by means of which at least one sliver guide can be controlled in such a way that the position and / or the draft of the sliver can be changed. By means of the actuators, for example, the sliver guides can be moved, so that also the sliver is also moved. As a result, the sliver can be displaced, for example, relative to the pairs of rolls in its axial direction, so that the sliver comes into contact with other areas of the lateral surfaces of the rolls. A wear of the roll surfaces can with this measure, for example be reduced. Also, the sliver guides can be adjusted for changes in the width of the sliver.

Furthermore, the rotational speed of individual pairs of rollers can be increased briefly in places of the sliver, where the drafting is less strong, to stretch the sliver at these points stronger. Thus, the points are compensated with a different stretching and the sliver has a higher regularity. The actuators include drives, in particular electric motors, which rotate the pairs of rollers.

Moreover, it is advantageous if the sliver guides comprise a band guide, shielding elements and / or a fleece funnel. By means of the tape guide, the spread fiber sliver can be compressed in its width and positioned transversely to the running direction of the sliver such that it is passed at a preferred position between the pairs of rollers, in particular of the input roller pair.

By the rotation of the rollers and their surfaces, air flows can be generated, in which the usually contoured lateral surfaces of the rollers entrain the air. These air currents move in the circumferential direction around the rollers and meet from the top of the top roller and from below from the bottom roller on the spread sliver. There, the air currents impinge on the sliver and are deflected to edge regions of the sliver, wherein such air flow pulls the sliver apart. In particular, at the edge regions, parts of the sliver are released from the composite, so that there dissolves the sliver. If the sliver guide comprises the shielding elements, detachment of the edge regions of the sliver by the air flows is prevented, which is advantageous for the quality of the sliver. The shielding prevent the existing air currents lead fibers toward the edge regions of the sliver and that the air currents cause the dissolution of the edge regions of the sliver.

By means of the fleece straightener, the spread-out fiber sliver can be combined to form a sliver having a substantially round cross-section. As a result, the sliver in a storage container, in particular in a pot, can be stored in a space-saving and gentle manner. In addition, the sliver has a form advantageous for further processing.

Another advantageous development of the invention is when the guide surfaces form opposite helical lines on the base body. One helix can be right-handed and the other helix can be left-handed.

It is also advantageous if the base body of the tape guide is mounted in the drafting system in a bearing, so that it is rotatable about an axial axis. For example, the rotation of the base body can be performed by means of an actuator. Also, the tape guide can be moved in the transverse direction to the direction of the sliver, so that the two guide surfaces entrain the sliver in this direction.

Moreover, it is advantageous if the tape guide has a scale for manual adjustment, in particular the rotation of the base body about its axial axis. The scale gives setting recommendations based on fiber data, such as a total fiber count, a fiber fineness, a total tape weight (ktex, Ne, etc.), a single tape weight, and / or a number of tapes. As a result, an optimal setting, in particular the rotation of the base body about its axial axis, the tape guide can be selected for different fiber types.

Furthermore, it is advantageous if the tape guide has an automatic adjustment, for example by means of the actuator, so that on the basis of the fiber data, such as the total number of fibers, the fiber fineness, the total tape weight (ktex, Ne, etc.), the individual belt weight and / or the number of bands, the base body is rotated about its axial axis. This can be done automatically on the different fiber types, so that always an optimal setting of the tape guide, in particular the rotation of the body about the axial axis, can be selected.

An additional advantageous development of the invention is when the at least one second sliver guide, which is arranged in the running direction of the sliver after the drafting, comprises a fleece funnel. The fleece funnel has an elongated entrance side where the spread sliver enters the fleece funnel and an exit side where the sliver of reduced cross-section emerges. On the output side, an output opening is arranged, through which the sliver emerges from the web straightener. Furthermore, the fleece funnel has at least two funnel surfaces adjacent between the input side and the exit side and the exit opening, the two funnel surfaces having at least one step. By means of such a web straightener, the spread sliver can be gently reduced in its cross section. A homogeneity of the emerging sliver is thus increased. In particular, the emerging sliver may have a substantially round cross section, so that the sliver can be gently stored in a pot.

Furthermore, it is advantageous if at least one guide element is arranged in the fleece funnel between the input side and the output side, which delimits a movement of the entering fiber sliver in its transverse directions. By means of the baffle will prevent different parts of the sliver when passing through the fleece funnel, which is detrimental to the quality of the exiting sliver.

Furthermore, it is advantageous if the at least one third sliver guide comprises at least two shielding elements, which are arranged in the running direction of the sliver in front of a pair of rollers and transversely to the direction of the sliver of this so spaced that the sliver is passed between the shielding. By means of these shielding elements, the sliver is not adversely affected, i. the shielding elements are arranged so as to be contactlessly spaced from the sliver. However, the shielding elements block the air currents that flow in the direction of the edges of the sliver and prevent dissolution of the edge regions of the sliver. The sliver is guided sideways.

It is also advantageous if the shielding elements project with a section into a wedge gap of the roller pair. Thus, an air flow is also prevented, which results from the fact that the sliver itself entrains the surrounding air, which then flows to the pair of rollers. Such air flow is deflected outwards on the roller pair in the direction of the end faces of the rollers. The air flow is concentrated in the wedge gap. With the portion which projects into the wedge-shaped gap, it is prevented that such air flow is deflected on the pair of rollers in the direction of the end faces. Such an air flow would in turn dissolve the edges of the sliver, so that the sliver would be reduced in its quality.

If the shielding elements are displaceable parallel to the axes of the roller pair, so that a distance between the shielding elements is variable, this also brings advantages. Thus, the shielding can be adjusted to different widths of the sliver. For example, if the width of the sliver is reduced by means of the first sliver guide, the spacing of the shielding elements can also be reduced can be reduced, so that the shielding elements are again pushed closer to the edges of the sliver. This will continue to prevent dissolution of the edges of the sliver. The shielding can be moved by the actuators, so that the adjustment can be performed quickly enough. For example, as soon as a sensor registers a change in the width of the fiber sliver, an actuator can change the spacing of the shielding elements at the desired location of the sliver so that the change in the width of the sliver is addressed substantially without a time delay.

Figur 1

eine Seitenansicht eines Streckwerks mit drei Walzenpaaren und drei Faserbandführungen,

Figur 2

eine perspektivische Ansicht einer ersten Faserbandführung ausgebildet als Bandführung,

Figur 3

eine Schnittansicht einer zweiten Faserbandführung ausgebildet als Vliestrichter,

Figur 4

eine Schnittansicht einer weiteren zweiten Faserbandführung ausgebildet als Vliestrichter mit einem Leitelement und

Figur 5

eine Schnittansicht des Faserbandes von der Schnittlinie A-A der Figur 1 der dritten Faserbandführung.

Further advantages of the invention are described in the following exemplary embodiments. Show it:

FIG. 1

a side view of a drafting system with three pairs of rollers and three sliver guides,

FIG. 2

a perspective view of a first sliver guide formed as a tape guide,

FIG. 3

a sectional view of a second sliver guide formed as a fleece funnel,

FIG. 4

a sectional view of a further second sliver guide designed as a non-woven strainer with a guide element and

FIG. 5

a sectional view of the sliver of the section line AA of FIG. 1 the third sliver guide.

In FIG. 1 is a side view of a drafting system 1 with three pairs of rollers 3, 4, 5 and three sliver guides 8, 9, 10 is shown. The three pairs of rollers 3, 4, 5 comprise an input roller pair 3, an intermediate roller pair 4 and a pair of output rollers 5. The respective roller pairs 3, 4, 5 comprise Furthermore, in each case at least one lower roller 6a-6c and at least one upper roller 7a-7d. The roller pairs 3, 4, 5 have a direction of rotation DR1, which is shown by way of example on the input roller pair 3. The directions of rotation of the lower roller 6a and the upper roller 7a are oppositely oriented, so that a sliver 2, which is passed between the pair of input rollers 3, taken along. The sliver 2 is transported in the running direction LR through the drafting system 1, so that it is passed after the pair of input rollers 3 between the intermediate roller pair 4. The lower roller 6b and the upper roller 7b of the intermediate roller pair 4 have the same directions of rotation DR1 as the lower roller 6a and the upper roller 7a. However, the rotational speed of the lower roller 6b and the upper roller 7b may be greater than the rotational speed of the lower roller 6a and the upper roller 7a. Due to the difference in the rotational speeds, the sliver 2 is accelerated by the intermediate roller pair 4, so that it is stretched. Subsequently, the sliver 2 passes in its running direction LR to the output roller pair 5. This comprises a lower roller 6c and two upper rollers 7c, 7d. The directions of rotation are again similar to the direction of rotation DR1 of the pair of input rollers 3. However, the pair of output rollers 5 may also have a higher rotational speed than the intermediate roller pair 4, so that the sliver 2 is further accelerated and thereby further stretched. An overall stretching of the sliver 2 is thus composed of the individual draws between the pair of input rollers 3 and the intermediate roller pair 4 as well as the intermediate roller pair 4 and the pair of output rollers 5.

Furthermore, the drafting system 1 also comprises at least the three sliver guides 8, 9, 10. In this case, a first sliver guide 8 comprises a sliver guide. The first sliver guide 8 is arranged in the running direction LR of the sliver 2 in front of the pair of input rollers 3. By means of the first sliver guide 8, the sliver 2 entering the drafting system 1 can be aligned in a position to the pair of input rollers 3, so that the sliver 2 at a certain point by the drafting 1 leads. In this case, the first sliver guide 8 may be arranged immediately in front of the pair of input rollers 3, so that the position at which the sliver 2 passes through the drafting system is more precisely determined.

In the running direction LR after the drafting system 1 and in particular after the output roller pair 5, a third sliver guide 9 is arranged. This includes, for example, a fleece funnel, which combines the spread and already stretched fiber sliver or fiber fleece to the sliver 2, which has a substantially round cross-section. After the third sliver guide 9, the combined sliver 2 can be stored in a pot, not shown here.

Furthermore, the drafting system 1 comprises a second sliver guide 10, which is arranged in this embodiment between the intermediate roller pair 4 and the pair of output rollers 5 and immediately in front of the pair of output rollers 5. Alternatively, the second sliver guide 10 may also be arranged between the pair of input rollers 3 and the intermediate roller pair 4 and / or in front of the pair of input rollers 3.

The second sliver guide 10 in this embodiment comprises at least two shielding elements (for reasons of perspective, only one is shown here), so that the sliver 2 is guided laterally. In particular, the second sliver guide 10 prevents widening of the sliver 2 by an air flow, which results from the rotation of the lower roller 6c and the upper roller 7c, from above and below on the sliver 2 and is deflected there in the direction of the edges of the sliver 2. The air flow is thus directed from an inner region of the sliver 2 in the direction of the edges of the sliver 2. At the edges of the air flow takes individual parts of the sliver 2, so that the sliver 2 widened. With increasing rotational speeds of the lower roller 6c and the upper roller 7c also becomes a stronger air flow educated. When exceeding a certain limit of the air flow, it may even come to dissolve parts of the sliver 2 at its edges, so that the quality of the drawn sliver 2 is no longer sufficient for further processing. The second sliver guide 10 prevents the flow of air which is directed from an inner region of the sliver 2 in the direction of the edges of the sliver 2, so that a widening and / or dissolution of the sliver 2 is prevented at the edges thereof.

In addition, the drafting system 1 sensors 11a-11c by means of which the position and / or the stretching of the sliver 2 can be registered. The sensors 11a-11c can be arranged in the direction LR of the sliver 2 in front of the respective sliver guides 8, 9, 10, so that after measuring the position and / or the stretching of the sliver 2, the sliver guides 8, 9, 10 by means not here shown actuators can be adjusted so that the position and / or the stretching can be changed immediately. For example, if the position of the sliver 2 is detected by the sensor 11a to be incorrect, the first sliver guide 8 can be adjusted immediately so that this position error is compensated. The sensors 11a-11c may be connected to a control unit, not shown here, which evaluates data from the sensors 11a-11c and correspondingly controls the actuators, also not shown here.

In FIG. 2 is a perspective view of a first sliver guide 8 (see. FIG. 1 ). The first sliver guide 8 is formed in this embodiment as a tape guide comprising an elongate base body 12 and two guide surfaces 13a, 13b. The two guide surfaces 13a, 13b form two oppositely oriented helices, so that they converge in the circumferential direction about the main body 12. In particular, a distance between the two guide surfaces 13a, 13b decreases continuously. Between the two guide surfaces 13a, 13b, the sliver 2 (see. FIG. 1 ).

By means of a bearing 14, the base body 12 is rotatable about an axial axis in the direction of rotation DR2. The main body 12 is rotatable in both directions of rotation DR2 (left and right), so that regions of the guide surfaces 13a, 13b can be turned off the sliver 2, which have a greater or lesser distance from one another. By means of the rotation of the main body 12, the guide surfaces 13a, 13b can be rotated relative to the sliver 2, so that the sliver 2 is passed past and at points on the main body 12 and between the guide surfaces 13a, 13b, at which the guide surfaces 13a, 13b have a smaller or a greater distance. As a result, the sliver can be guided and adapted in particular in its width.

In the FIG. 3 is a sectional view of a second sliver guide 9 (see. FIG. 1 ), which is formed as a fleece funnel. The second sliver guide 9 has an elongated input side 15, at which the sliver 2 (see. FIG. 1 ) enters the second sliver guide 9. At an exit side 16, the sliver 2 exits through an exit opening 17. When the sliver 2 emerges from the second sliver guide 9, it has a reduced cross section, in particular, the spread sliver 2 becomes a sliver 2 having a substantially round cross section.

Furthermore, the second sliver guide 9 has at least two funnel surfaces 18a, 18b between the input side 15 and the output side 16. If the sliver 2 hits the funnel surfaces 18a, 18b from the direction of the input side 15, the sliver 2 is diverted in the direction of the exit opening 17. In this case, at least parts of the edges of the sliver 2 slip over gradations 19a, 19b, which are arranged in the funnel surfaces 18a, 18b. By means of the gradations 19a, 19b, a flow of the sliver 2 of the funnel surfaces 18a, 18b to the outlet opening 17 homogeneous, so that the quality of the emerging sliver 2 is improved. The funnel surfaces 18a, 18b also have an angle α, which is preferably the same for both funnel surfaces 18a, 18b, but may also be different.

In FIG. 4 a further embodiment of the second sliver guide 9 is shown, which is designed as a fleece funnel and has a guide element 20. In addition, it is intended only to the essential differences to the FIG. 3 To be received.

Between the input side 15 and the outlet opening 17, the guide element 20 is arranged. This is located adjacent to exit port 17, i. the guide element 20 does not engage in a cross section of the outlet opening 17 a. The guide element 20 also limits a movement of the sliver 2, as it flows from the funnel surfaces 18 a, 18 b in the direction of the outlet opening 17. For example, portions of the sliver 2 coming from the funnel surface 18a are prevented from flowing over the exit opening 17 and interacting with portions of the sliver 2 which flow from the funnel surface 18b toward the exit opening 17. This improves the quality of the emerging sliver. Additionally or alternatively, the guide element 20 may have a roof element, so that parts of the sliver coming from the input side 15 are gently guided over the guide element 20 away.

In the FIG. 5 is a sectional view of the sliver 2 from the section line AA of FIG. 1 , with a third sliver guide 10, the lower roller 6c and the upper roller 7c. The sliver 2 is passed between these two rollers. In this exemplary embodiment, the third sliver guide 10 comprises two shielding elements 22a, 22b, which have a spacing 21 from one another in a transverse direction to the sliver 2. The two shielding elements 22a, 22b can by means not shown actuators be moved in the transverse direction of the sliver 2, so that the distance 21 can be changed. This is advantageous if the width of the sliver 2 varies, so that the shielding elements 22a, 22b can be adapted to the width of the sliver 2.

The shielding elements 22a, 22b prevent an outward flow from the air currents, which are caused by the rotations of the lower roller 6c and top roller 7c and hit the sliver 2. As a result, a dissolution of the edge regions of the sliver 2 is prevented.

The present invention is not limited to the illustrated and described embodiments. Variations within the scope of the claims are also possible as a combination of features, even if they are shown and described in different embodiments.

LIST OF REFERENCE NUMBERS

1

drafting system

2

sliver

3

Pair of input rollers

4

Between roller pair

5

Roller pair

6

bottom roll

7

top roll

8th

First sliver guide

9

Second sliver guide

10

Third sliver guide

11

sensor

12

body

13

baffle

14

camp

15

input side

16

output side

17

output port

18

funnel surface

19

gradation

20

vane

21

distance

22

screening

LR

direction

DR

direction of rotation

Claims (12)

1. A drafting system for drafting a fiber sliver (2), having at least three roller pairs (3, 4, 5) disposed one after the other in the running direction (LR) of the fiber sliver (2), each comprising at least one bottom roller (6a-6c) and at least one top roller (7a-7d), the fiber sliver (2) being fed between a roller pair (3, 4, 5) each, having at least one sliver guide (8, 9, 10) by means of which the fiber sliver (2) is guided, at least one first sliver guide (8) being disposed upstream of the drafting system (1) in the running direction (LR) of the fiber sliver (2) and at least one second sliver guide (9) being disposed downstream of the drafting system (1) in the running direction (LR) of the fiber sliver (2), and wherein a third sliver guide (10) is disposed between two roller pairs (3, 4, 5) and/or upstream of a first roller pair (3) in the running direction (LR) of the fiber sliver (2), so that the fiber sliver (2) is guided laterally characterized in that the first sliver guide (8) comprises a band guide, implemented as an elongated base body (12), having two helically guide surfaces (13a, 13b), disposed on the base body (12), wherein the base body (12) can be rotated.
2. The drafting system according to the preceding claim, characterized in that the drafting system (1) comprises sensors (11) by means of which a position and/or a drafting of the fiber sliver (2) can be detected.
3. The drafting system according to any one or more of the preceding claims, characterized in that the drafting system (1) comprises a control unit by means of which the data from the sensors (11) can be evaluated.
4. The drafting system according to any one or more of the preceding claims, characterized in that the drafting system (1) comprises actuators by means of which at least one sliver guide (8, 9, 10) can be controlled such that the position and/or the drafting of the fiber sliver (2) can be modified.
5. The drafting system according to any one or more of the preceding claims, characterized in that the sliver guides (8, 9, 10) comprise a band guide, shielding elements, and/or a web funnel.
6. The drafting system according to any one or more of the preceding claims, characterized in that the guide surfaces (13a, 13b) implement opposite helixes, particularly one right-handed and one left-handed helix, on the base body (12).
7. The drafting system according to claim 1, characterized in that the base body (12) of the band guide is supported in a bearing (14) in the drafting system (1) so that said base body can rotate about an axial axis.
8. The drafting system according to any one or more of the preceding claims, characterized in that the at least one second sliver guide (9) disposed downstream of the drafting system (1) in the running direction (LR) of the fiber sliver (2) comprises a web funnel having an elongated inlet side (15) at which the expanded fiber sliver (2) enters the web funnel and an outlet side (16) at which the fiber sliver (2) exits having a reduced cross section, said web funnel having an outlet opening (17) disposed on the outlet side (16), and having at least two funnel surfaces (18a, 18b) between the inlet side (15) and the outlet side (16) and adjacent to the outlet opening (17), wherein the two funnel surfaces (18a, 18b) comprise at least one stepping (19a, 19b).
9. The drafting system according to any one or more of the preceding claims, characterized in that at least one guide element (20) is disposed in the web funnel between the inlet side (15) and the outlet opening (17) and limits a motion of the entering fiber sliver (2) in the transverse directions thereof.
10. The drafting system according to any one or more of the preceding claims, characterized in that the at least one third sliver guide (10) comprises at least two shielding elements (22a, 22b) disposed upstream of one of the three roller pair (3, 4, 5) in the running direction (LR) of the fiber sliver (2) and spaced apart from the fiber sliver (2) perpendicular to the running direction (LR) thereof, such that the fiber sliver (2) is guided through the shielding elements (22a, 22b).
11. The drafting system according to claim 10, characterized in that a segment of the shielding elements (22a, 22b) protrudes into a wedge gap of the roller pair (3, 4, 5).
12. The drafting system according to claims 10 or 11, characterized in that the shielding elements (22a, 22b) are displaceable parallel to the axes of the roller pair (3, 4, 5), so that a spacing (21) between the shielding elements (22a, 22b) can be changed.

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