EP4177387A1 - Drawing frame for a textile machine - Google Patents

Abstract

In a drafting system (1) for a textile machine, in particular an air-jet spinning machine, for drafting a strand-like fiber structure fed to the drafting system, comprising a plurality of pairs of rollers arranged one after the other in a running direction (A) of the fiber structure, each with an upper roller (3) and a lower roller (4), and a loading device for loading the top roller (3) of the plurality of roller pairs; the respective lower roller (4) being mounted and held in a housing (2) of the drafting system (1), and the respective upper roller (3) being mounted in the housing (2) of the drafting system ( 1) is mounted and held, it is provided that the drafting system (1) further comprises a pivotable loading arm (20) which can be brought into an open position and a closed position, the loading arm (20) having an individually adjustable loading device for each pair of rollers (40) which, when the loading arm (20) is closed, loads the respective pivotable top roller carrier (30) in a loading position.

Description

technical field

The invention relates to a drafting arrangement for a textile machine, in particular an air-jet spinning machine, comprising a plurality of pairs of rollers arranged one after the other in a running direction of a fiber structure and a loading device for loading the top roller of the plurality of pairs of rollers.

Technical background

Drafting systems for a textile machine have been known for a long time. They are used to draw a strand-like fiber assembly fed to the drafting system. The fibers of a sliver are pulled apart to form a finer sliver. The basic principle of the drafting systems is based on a delay in the fiber structure between at least two rotating machine parts, resp. Pairs of rollers that run at different peripheral speeds.

While most of the fiber material is held in place by the first, slower pair of rollers, some of the fibers pass between the faster pair of rollers. This transports the fibers forward, creating a thinner fiber structure. The capacity of a drafting system with two pairs of rollers is limited, which is why drafting systems with several pairs of rollers and so-called aprons are used. The straps increase the fiber guidance and the restraining forces for the fibers. Such straps were already described by Fernando Casablancas at the beginning of the 20th century.

CH683698 describes a drafting system for a fine spinning machine with at least three pairs of rollers comprising upper and lower rollers. The lower rollers are designed with a common drive for at least two drafting systems arranged next to one another. The bottom rollers are attached to a shaft on both sides and are mounted in a housing for the two drafting systems. The upper rollers are individually spring-mounted on a loading arm, each in a rotatable carrier and arranged laterally to the loading arm. The rotatable carrier is mounted by means of bearing bushes on an L-shaped support part, which is attached to the loading arm without play. Such a support and loading arm therefore includes top rollers for two drafting systems, which are arranged on both sides of the support and loading arm. The problem with such a drafting system is that an uneven load is applied to the top rollers in the axial direction directed forces on the fiber structure. Independent adjustment of the pairs of rollers for individual spinning positions is also not possible. In addition, it is not possible to swivel out the top rollers individually.

A further variant of a drafting system for drafting a strand-like fiber structure fed to the drafting system is from CH712605 and CH713498 is known, this drafting arrangement comprising at least two drafting arrangement modules arranged one behind the other in a transport direction of the fiber structure and having a lower and an upper roller. Each drafting system module has a separate carrier on which the upper and lower rollers are mounted. The top roller is mounted via a mount in such a way that it can be moved back and forth between a loading position and a relief position independently of the rollers of the other drafting system modules. In contrast to the storage of all rollers on a support arm, which is only supported on one side via a swivel joint, in this variant the top rollers are each mounted on their own support and loading arm. The adhesion between the top and bottom rollers can be adjusted individually. However, it is not possible to swing out the top rollers completely one at a time. Another disadvantage is that the roller is loaded on one side, which can lead to the axes of the upper and lower rollers not being parallel. If there is a change in the load, this error must be determined and, if necessary, corrected.

In EP1431433 a drafting system with three pairs of rollers is described, the upper rollers being able to be lifted off the lower rollers. At least one top roller can be lifted independently of the remaining top rollers. For this purpose, the top rollers are attached to two support and load arms. The top rollers are each held in a guide of a top roller yoke and are spring-loaded. However, such a guide is subject to friction, which means that a reset after the top roller has been raised works too slowly or only poorly due to thick points in the fiber structure, out-of-roundness of the rollers or the like. In addition, the top roller is loaded on both sides with a spring, which means that precise and symmetrical force adjustment is hardly possible.

Drafting systems are also known ( DE102019115905 A1 ), in which the top rollers are held laterally by two arms. The disadvantage of such a variant is that the load on the top roller is applied on both sides via two load structures, making it difficult to set a load force precisely because both load structures have to be set exactly. In addition, lateral visibility and operability may be restricted.

Drafting systems for air-jet spinning machines have very high operating speeds compared to other spinning machines and must therefore be able to be stopped immediately, e.g. in the event of a thread breakage in the spinning position. It is therefore advantageous to drive the rollers individually and, if necessary, to be able to open the stopped drafting system immediately. Because of the high operating speeds, precise positioning of the rollers with low tolerances of, for example, a maximum of 2/10 mm is advantageous. Such an exact positioning of the rollers is not or hardly possible with the known drafting systems, or at most with a very large amount of work.

Presentation of the invention

One object of the invention is to specify a drafting system for drafting a strand-like fiber assembly fed to the drafting system, which also satisfies the requirements for air-jet spinning machines and avoids the problems described above.

This object is achieved by a drafting system for a textile machine, in particular an air-jet spinning machine, having the features of claim 1. The drafting system for drafting a strand-like fiber structure fed to the drafting system comprises several pairs of rollers arranged one after the other in a running direction of the fiber structure, each with an upper roller and a lower roller and a loading device for loading the upper roller of the several roller pairs. The bottom roller is mounted and held in a housing of the drafting system. The top roller is mounted and held in the housing of the drafting system by means of a top roller carrier that can be pivoted about an axis of rotation. The drafting system also includes a pivotable loading arm which can be brought into an open position and a closed position. The loading arm has an individually adjustable loading device for each pair of rollers, which, when the loading arm is closed, loads the respective pivotable upper roller carrier in a loading position.

Such a drafting system has several advantages over known drafting systems.

The top roller is not caught in a loading arm, but is pivotably arranged in the drafting system housing. Accordingly, the positioning of the lower and upper rollers is decoupled from the loading device, ie it is independent of the positioning of the loading device. The loading arm is only used to load the pairs of rollers and not to position and support the top rollers. The position of the bottom and top rollers can be adjusted easily and independently of the load become. This leads to lower tolerances in the exact positioning of the rollers in relation to one another.

In addition, each top roller is loaded individually and their loading can be set individually and/or together. Partial relief is also possible, e.g. when the spinning position is at a standstill, so that the top rollers do not flatten out during the standstill, but the fibers are still held by the pair of rollers.

Overall, the drafting system has very good accessibility for thread piecing or for changing rollers and replacing aprons. Only one spinning position has to be stopped and neighboring spinning positions can continue to run unhindered. Overall, the drafting system is clearly visible from the side. The drafting systems are designed in such a way that good visibility is guaranteed from the same side in each case, so that they can be checked easily and quickly when checking around spinning machines.

The housing of the drafting system means the supporting structure in which the individual parts of the drafting system are mounted directly or indirectly, respectively. are attached.

In some embodiments, the lower rollers can each be mounted on a lower roller carrier fastened in the housing. As a rule, the pivotable upper roller support can be connected to the lower roller support such that it can pivot about an axis of rotation of the upper roller support. Such a lower roller support can be displaced along the running direction of the fiber structure and can be fixed in a desired position in order to bring the individual lower rollers into the desired position. Known templates can be used as positioning aids for the rollers.

In some embodiments, the axis of rotation of the top roller support in the direction of travel of the fiber structure is arranged after or before the pair of rollers, so that the top roller support in the direction of travel, respectively. can be swung out against the running direction. The pairs of rollers can therefore be aligned in such a way that the upper roller remains pivotable even when the pairs of rollers are arranged close to one another. The position of the axis of rotation and the shape of the upper roller carrier can be selected in such a way that the upper roller can be moved essentially upwards away from the lower roller when pivoted out. The roller support can have a straight, angled or curved shape. As a rule, it has a contact surface for the loading device, which extends parallel to the plane of the drafting system.

In some embodiments, a top roll axis of the top roll can be mounted on both sides in a top roll yoke fastened to the top roll carrier. The The upper roller axis of the upper roller is thus loaded evenly on both sides and tilting of the upper roller axis is prevented, even if a force is applied which is asymmetrical to the middle of the roller.

A top roller axis of the top roller can be secured by means of a top roller safety device in the top roller yoke, e.g. in a corresponding groove of the top roller yoke. The top roller safety device can preferably be released by hand. In this way, the top roller can be replaced quickly and without tools. The upper roller yoke can be attached to the upper roller carrier so that it can be displaced along the running direction of the fiber structure, so that the upper roller can be brought and fixed in a desired position relative to the lower roller. In this way it is possible to set a so-called lead or lag of the top roll to the bottom roll. Templates can also be used here as positioning aids.

In some embodiments, the loading device can have a loading element, preferably a pneumatic or spring-loaded loading element selected, for example, from the group of pneumatic cylinders, air springs, spiral springs, leaf springs, diaphragm cylinders, diaphragm pressure elements and bellows. A loading element can act on a single pair of rollers or simultaneously on several pairs of rollers.

In some embodiments, the loading device or the loading element on the loading arm can be moved and fixed in different positions along the running direction of the fiber structure, so that a point of application of the loading can be brought and fixed by the loading device at a desired position of the top roller support. In this way, the loading effect can be optimized. Depending on the position, the lever of the top roller carrier is increased or decreased. With each loading device, the force acting on the top roller can be individually adjusted.

In some embodiments, the loading device can have a convex loading head, in which case the loading head can be moved and fastened to different positions along the running direction of the fiber structure on the top roller support, so that a point of application of the load by the loading device can be brought and fixed in a desired position relative to the top roller support . The convex loading head can be hemispherical, dome-shaped or mushroom-shaped.

In some embodiments, the loading arm may be lockable with no play in a closed position. For this purpose, a fixed stop is preferably present in the housing of the loading arm.

In some embodiments, the loading device can be brought into a loading position or a relieving position when the loading arm is in the closed position. The loading devices of a drafting system can be brought into the loading position or the unloading position individually or in a group.

In some embodiments, the point of application of the load by the loading device can be offset from the center of the top roll along the top roll axis. In other words, the point of action of the loading device can be arranged asymmetrically in all pairs of rollers relative to the center of the top roller and offset along the axis of the top roller to the same side, so that the visibility and operability of the drafting system is increased from one side. This increases visibility from the same side and leads to easier and faster checking of the drafting systems when checking rounds around the spinning machine.

In the drafting arrangement described, the contact pressure of the pairs of rollers can be adjusted individually via the loading devices, in that on the one hand the force of the loading elements can be controlled and on the other hand the point of action of the loading device can be brought to the desired position on the top roller carrier.

Furthermore, one or more upper and/or lower rollers can be wrapped with a strap, as is already known in the prior art. The respective straps can be guided with one or more additional guide elements in addition to the guide over the corresponding roller or counter-roller.

Furthermore, the bottom rollers in the drafting system can be overhung or mounted on both sides.

Brief explanation of the figures

Fig. 1

eine schematische Seitenansicht auf ein Streckwerk;

Fig. 2

ein Ausschnitt des Streckwerks aus Fig. 1;

Fig. 3

eine Schnittdarstellung einer Oberwalzenaufhängung mit Belastungseinrichtung;

Fig. 4

ein Ausschnitt des Streckwerks mit einer Belastungseinrichtung mit bewegbarem Belastungskopf;

Fig. 5

unter (a) eine Belastungseinrichtung mit bewegbarem Belastungskopf und unter (b) eine Detailansicht aus Fig. 5(a);

Fig. 6

eine Draufsicht auf einen Belastungskopf;

Fig. 7

eine Belastungseinrichtung mit einem Belastungselement für mehrere Walzenpaare.

The invention will be explained in more detail below using exemplary embodiments in connection with the drawing(s). Show it:

1

a schematic side view of a drafting system;

2

a section of the drafting system 1 ;

3

a sectional view of a top roller suspension with loading device;

4

a section of the drafting system with a loading device with a movable loading head;

figure 5

under (a) a loading device with a movable loading head and under (b) a detailed view Fig.5(a) ;

6

a plan view of a loading head;

7

a loading device with a loading element for several pairs of rollers.

Ways to carry out the invention

In 1 a schematic side view of an embodiment of a drafting system for a textile machine is shown. The drafting system 1 has several pairs of rollers and is particularly suitable for an air-jet spinning machine in which precise positioning and loading of the pairs of rollers is essential due to the high spinning speeds. 2 shows a section 1 with a pair of rollers.

The drafting system 1 comprises several pairs of rollers arranged one after the other in a running direction A of a fiber structure, each with an upper roller 3 and a lower roller 4. The drafting system can also have aprons known from the prior art, which are not shown here. The bottom roller 4 can be mounted in a known manner on a bearing block or a bottom roller carrier 2a in the drafting system housing 2. As a rule, their positioning relative to the running direction A can be adjusted and fixed.

Each top roller 3 is fastened to a top roller carrier 30 that can be pivoted about an axis of rotation 31 . The axis of rotation 31 runs parallel to the axes of rotation of the rollers. The pivotable upper roller carrier 30 is connected to the bearing block or the lower roller carrier 2a of the lower roller 4 or the drafting system housing. To mount the top roller 3 , the top roller carrier 30 can have a top roller yoke 32 which is connected to the top roller carrier 30 . This connection is designed in such a way that the top roller yoke 32 can be moved relative to the top roller carrier 30 in the running direction A of the drafting system and can be fixed at the desired position. This allows a precise positioning of the upper roller 3 in relation to the lower roller 4. In particular, in this way a pre-hang or lag of the upper roller 3 relative to the lower roller 4 can be adjusted. Relocatability is in 2 and 4 indicated with arrow C.

The upper roller yoke 32 loads the upper roller axis 34 on both sides, so that an even contact pressure of the two rollers is achieved.

The axis of rotation 31 of the top roller carrier 30 can also be arranged further down than shown in the figures and closer to the axis of rotation of the top roller 3 . In this case, instead of the straight top roller support 30 shown, an angled or curved top roller support can also be used.

In order to keep the top roller 4 in the bearing of the top roller yoke 32, in particular when the top roller carrier 31 swings out, a top roller safety device 33, e.g. in the form of a leaf spring, is provided in the embodiment shown, which acts on the top roller axis 34. This can be easily released by hand so that the upper roller axis 34 with the upper roller 4 can be easily removed from the bearing on the upper roller yoke 32 . Other configurations of the upper roller safety device 33 are also possible.

A loading arm 20 is arranged above the top rollers 4 and is pivotably connected to the drafting system housing 2 via an axis of rotation 21 . The axis of rotation 21 also runs parallel to the axes of rotation of the rollers. The loading arm 40 is reciprocable between an open position and a closed position. In the closed position, the loading arm 40 preferably rests against a fixed stop 24 and can be secured in position by means of a lock 23, so that it assumes a play-free and precisely defined position in the closed position.

A loading device 40 is arranged on the loading arm 20 for each pair of rollers. The loading device 40 serves to load a top roller 3 in each case. For this purpose, the loading device 40 has a loading element 41 and a convex loading head 42 . The loading element can be designed as a pneumatic or spring-loaded loading element (for example as a pneumatic cylinder, air spring, spiral spring, leaf spring, diaphragm cylinder, diaphragm pressure element or bellows). The loading head 42 provides a precisely positionable point of action of the load by the loading device 40 on the top roller carrier 30. The load can be finely adjusted by shifting the point of action.

In the embodiment shown, the loading device 40 or the loading element 41 is held in the loading arm 20 so that it can be moved and fixed, so that it can be fixed at a desired position relative to the top roller carrier 30 in the running direction A of the drafting system. With this displaceability, the point of action of the loading element 41 can be relative to the upper roller support 30, respectively. of the top roller 3 can be adjusted in order to fine-tune the To achieve contact pressure of the upper roller 3 on the lower roller 3. Relocatability is in 2 indicated with arrow B.

In 3 a sectional view of a top roller suspension with loading device 40 described above is shown. The upper roller axis 34 of the upper roller 4 is mounted in the upper roller yoke 32 . The top roller yoke 32 is attached to the top roller carrier 30 in a displaceable and fixable manner. In the embodiment shown, a projection of the top roller yoke 32 is guided in a guide of the top roller carrier 30 . The upper roller yoke 32 can be fixed with a screw. The loading device 40 can be connected to the loading arm 20 in the same way.

The point of application of the load from the loading device 40 is arranged asymmetrically in all pairs of rollers relative to the center of the top roller 3 and offset to the same side along the axis 34 of the top roller, so that the visibility and operability of the drafting system is increased from one side.

4 shows a section of the drafting system with a further embodiment of a loading device. In contrast to the loading device 2 For example, the convex loading head 42 can be fastened to the upper roller support 31 in different positions along the running direction A of the drafting system and contacts the loading element 41 with the convex side. The fine adjustment described above can be achieved by shifting (arrow D) the loading head 42 . This embodiment has the advantage that when the lower roller support 2a is displaced, the point of application of the load by the loading device 40 is not displaced relative to the upper roller support 31 and any new fine adjustment is not necessary.

Fig.5(a) shows an embodiment of the loading device with a membrane cylinder as the loading element 41. Furthermore, a convex loading head 42 that can be fastened to the upper roller support 30 at various positions is shown. Fig.5(b) shows a larger detail view Fig.5(a) .

In the variant, the loading head 42 has two pins 43 on an underside opposite the convex side, which can be inserted into double bores 35 in the upper roller support 30 . In order to position the loading head 42 at different points, the top roller carrier 30 has a plurality of double bores 35 (cracks) arranged at equal intervals. A plan view of the underside of the loading head is in 6 shown.

The pins 43 are offset from the axis of the loading head 42 by 1/4 the distance of the double bores 35 . By the loading head 42 alternately rotated 180° and inserted into the double bores 35, the number of jumps can be doubled to the number of double bores 35. In order to visually check the orientation of the loading head 42, inclined surfaces can be formed on a base of the loading head 42.

The convex side of the loading head 42 is designed in the shape of a sphere, dome or mushroom, so that a membrane of the membrane cylinder does not require any hard surface at all. The substructure of the loading head resp. the lower roller support 2a can be moved a little without the membrane cylinder having to be moved as well.

The pins can also be rectangular or oval in shape, so that independent twisting of the loading head 42 is prevented even with only one pin.

In order to achieve a higher load, the membrane cylinder can be designed oval or elliptical.

7 shows in contrast to figure 5 an embodiment of the loading device 40 with a membrane element as a loading element 41, which extends over several pairs of rollers. The membrane element can be designed in the form of a hose or a sausage and acts on the loading head 42 of several pairs of rollers. The effect of the force can be adjusted individually by positioning the loading head 42 relative to the top roller support 30 .

designation list

1

drafting system

2

Drafting system housing (supporting structure)

2a

bottom roller carrier

3

top roller

4

bottom roller

20

Low-impact

21

Axis of rotation low-stress

23

Locking of the loading arm

24

attack

30

top roller carrier

31

Axis of rotation of the top roller carrier

32

upper roller yoke

33

top roller safety device

34

top roll axis

35

double bore

40

loading device

41

loading element

42

convex loading head

43

Pen

A

grain direction

B

mobility loading element

C

Movability of the upper roller yoke

D

Movability loading head

Claims (15)

Drafting system (1) for a textile machine, in particular an air-jet spinning machine, for stretching a strand-like fiber structure fed to the drafting system several pairs of rollers arranged one after the other in a running direction (A) of the fiber structure, each having an upper roller (3) and a lower roller (4), and a loading device for loading the upper roller (3) of the several pairs of rollers; wherein the respective bottom roller (4) is mounted and held in a housing (2) of the drafting system (1), and the respective upper roller (3) being mounted and held in the housing (2) of the drafting system (1) by means of an upper roller carrier (30) which can be pivoted about an axis of rotation, characterized in that the drafting system (1) further comprises a pivotable loading arm (20) which can be brought into an open position and a closed position, the loading arm (20) having an individually adjustable loading device (40) for each pair of rollers, which, when the loading arm (20) is closed, loads the respective pivotable upper roller carrier (30) in a loading position. Drafting system according to Claim 1, characterized in that the lower rollers (4) are each mounted on a lower roller carrier (2a) fastened in the housing (2). Drafting system according to Claim 2, characterized in that the lower roller carrier (2a) can be displaced along the running direction (A) of the fiber structure and can be fixed in a desired position. Drafting system according to one of Claims 2 or 3, characterized in that the pivotable upper roller carrier (30) is connected to the lower roller carrier (2) so that it can pivot about an axis of rotation (31) of the upper roller carrier (30). Drafting system according to one of the preceding claims, characterized in that the axis of rotation (31) of the upper roller carrier (30) in the direction (A) of Fiber structure is arranged after or before the pair of rollers, so that the upper roller support (30) in the direction (A) resp. can be swung out against the running direction (A). Drafting system according to one of the preceding claims, characterized in that a top roller axis (31) of the top roller (3) is mounted on both sides in a top roller yoke (32) fastened to the top roller carrier (30). Drafting system according to Claim 6, characterized in that an upper roller axis (31) of the upper roller (3) is secured in the upper roller yoke (32) by means of an upper roller safety device (33), which can preferably be released by hand. Drafting system according to Claim 6 or 7, characterized in that the upper roller yoke (32) is attached to the upper roller carrier (30) so that it can be displaced along the running direction (A) of the fiber structure, so that the upper roller (3) can be moved to a desired position relative to the lower roller (4). can be brought and fixed. Drafting system according to one of the preceding claims, characterized in that the loading device (40) has a loading element (41), preferably a pneumatic or spring-loaded loading element selected, for example, from the group of pneumatic cylinders, air springs, spiral springs, leaf springs, diaphragm cylinders, diaphragm pressure elements and bellows. Drafting system according to one of the preceding claims, characterized in that the loading device (40) or the loading element (41) on the loading arm (20) can be moved and fixed in different positions along the running direction (A) of the fiber structure, so that a point of action of the loading by the loading device (40) can be brought and fixed at a desired position on the top roller carrier (30). Drafting system according to one of the preceding claims, characterized in that the loading device (40) has a convex loading head (42), the loading head (42) being movably fastened to the upper roller carrier (30) in different positions along the running direction (A) of the fiber structure, so that a point of action of the load can be brought and fixed in a desired position relative to the upper roller carrier (30) by the loading device. Drafting system according to one of the preceding claims, characterized in that the loading arm (20) can be locked without play in a closed position. Drafting system according to one of the preceding claims, characterized in that the loading device (40) can be brought into a loading position or a relieving position when the loading arm (20) is in the closed position. Drafting system according to Claim 11, characterized in that the loading devices (40) of a drafting system can each be brought into the loading position or the relief position individually or in a group. Drafting system according to one of the preceding claims, characterized in that the point of application of the loading by the loading device (40) is offset relative to the center of the top roller (3) along the top roller axis (34).

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