DRAWING SYSTEM FOR A TEXTILE MACHINE

Description

Technical area

[0001] The invention relates to a drafting device for a textile machine, in particular an air-jet spinning machine, comprising a plurality of roller pairs arranged one after the other in a running direction of a fiber structure and a loading device for loading the upper roller of the plurality of roller pairs. Technical background

[0002] Drafting systems for textile machines have been around for a long time. They are used to draw a strand-like fiber bundle fed into the drafting system. In this process, fibers from a fiber sliver are drawn apart to form a finer sliver. The basic principle of drafting systems is based on the drafting of the fiber bundle between at least two rotating machine parts or pairs of rollers that run at different peripheral speeds.

[0003] While most of the fiber material is held by the first, slower pair of rollers, a portion of the fibers passes between the faster pair of rollers. This transports the fibers forward, creating a thinner fiber strand. The capacity of a drafting system consisting of two pairs of rollers is limited, which is why drafting systems consisting of several pairs of rollers and so-called aprons are used. The aprons increase fiber guidance and the restraining forces on the fibers. Such aprons were first described by Fernando Casablancas at the beginning of the 20th century.

[0004] CH683698 (EP0488007A1) describes a drafting system for a fine spinning machine with at least three pairs of rollers comprising top and bottom rollers. The bottom rollers are designed for at least two adjacent drafting systems with a common drive. The bottom rollers are attached to a shaft on both sides and mounted in a housing for the two drafting systems. The top rollers are individually mounted on a loading arm, each spring-loaded in a rotatable support and arranged laterally to the loading arm. The rotatable support 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 comprises 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 uneven loading on the top rollers leads to axially directed forces on the fiber structure.Independent adjustment of the roller pairs for individual spinning stations is also not possible. Furthermore, individual pivoting of the top rollers is not possible.

[0005] A further variant of a drafting system for drawing a strand-shaped fiber structure fed to the drafting system is known from CH712605 and CH713498, wherein this drafting system comprises at least two drafting system modules arranged one behind the other in a transport direction of the fiber structure, each comprising a bottom roller and a top roller. Each drafting system module has a separate support on which the top and bottom rollers are mounted. The top roller is mounted via a holder 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 mounting all rollers on a support arm that is only mounted on one side via a pivot joint, in this variant the top rollers are each mounted on their own support and loading arm. The frictional connection between the top and bottom rollers can be individually adjusted.However, a complete pivoting of the top rollers is not possible. A further disadvantage is that the roller's loading is one-sided, which can lead to the axes of the top and bottom rollers not running parallel. If the load changes, this error must be determined and corrected if necessary.

[0006] EP1431433 describes a drafting system with three pairs of rollers, with the top rollers being able to be lifted from the bottom 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 loading 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 resetting after lifting the top roller is too slow or poorly performed due to thick spots in the fiber structure, roller out-of-roundness, or the like. In addition, the top roller is loaded with a spring on each side, making precise and symmetrical force adjustment almost impossible.

[0007] Drafting systems are also known (DE102019115905 A1) in which the top rollers are held laterally by two arms. The disadvantage of this variant is that the load on the top roller is applied on both sides via two loading structures, making it difficult to precisely adjust the load force because both loading structures must be precisely adjusted. Furthermore, lateral visibility and operability may be limited.

[0008] Compared to other spinning machines, drafting systems for air-jet spinning machines operate at very high speeds and therefore require the ability to stop immediately, for example, in the event of a yarn breakage in the spinning station. Therefore, it is advantageous to drive the rollers individually and to be able to immediately open the stopped drafting system individually if necessary. Due to the high operating speeds, precise positioning of the rollers with tight tolerances of, for example, a maximum of 2 / 10 mm is also advantageous. Such precise positioning of the rollers is not possible, or hardly possible, with conventional drafting systems, or at most requires a very large amount of effort. Description of the invention

[0009] An object of the invention is to provide a drafting system for drawing a strand-shaped fiber structure fed to the drafting system, which also meets the requirements for air-jet spinning machines and avoids the problems described above.

[0010] This object is achieved by a drafting system for a textile machine, in particular an air-jet spinning machine, with the features of claim 1. The drafting system for drawing a strand-shaped fiber structure fed to the drafting system comprises several roller pairs arranged one after the other in a running direction of the fiber structure, each pair having a top roller and a bottom roller, and a loading device for loading the top 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 pivotable about a rotational axis. The drafting system further comprises 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 loads the respective pivoting top roller carrier when the loading arm is closed in a loading position.

[0011] Such a drafting system has several advantages over known drafting systems.

[0012] The top roller is not trapped in a loading arm, but is pivotably mounted in the drafting system housing. Accordingly, the positioning of the bottom and top rollers is decoupled from the loading device, meaning it is independent of the positioning of the loading device. The loading arm serves only to load the roller pairs and not to position and support the top rollers. The position of the bottom and top rollers can thus be easily adjusted independently of the load. This leads to smaller tolerances in the precise positioning of the rollers relative to each other.

[0013] In addition, each top roller is individually loaded, and their load can be adjusted individually and / or jointly. Partial unloading is also possible, for example, during a standstill at the spinning station, so that the top rollers do not flatten during the standstill, but the fibers are still held by the pair of rollers.

[0014] The drafting system offers excellent accessibility for yarn piecing or roller and apron replacement. Only one spinning station needs to be stopped, allowing neighboring spinning stations to continue running unhindered. The drafting system is easily visible from the side. The drafting systems are designed to ensure good visibility from the same side, allowing for quick and easy inspection during inspection rounds around spinning machines.

[0015] The housing of the drafting system refers to the supporting structure in which the individual parts of the drafting system are directly or indirectly mounted or fastened.

[0016] In some embodiments, the lower rollers can each be mounted on a lower roller support mounted in the housing. Typically, the pivotable upper roller support can be pivotally connected to the lower roller support about a rotational axis of the upper roller support. Such a lower roller support can be displaced along the running direction of the fiber strand and fixed in a desired position to bring the individual lower rollers into the desired position. Known templates can be used as positioning aids for the rollers.

[0017] In some embodiments, the rotational axis of the top roller support can be arranged after or before the roller pair in the running direction of the fiber structure, so that the top roller support can be pivoted in the running direction or against the running direction. The roller pairs can therefore be aligned such that the top roller remains pivotable even when the roller pairs are arranged close to one another. The position of the rotational axis and the shape of the top roller support can be selected such that the top roller can be moved essentially upwards away from the bottom roller when pivoting 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 drafting system plane.

[0018] In some embodiments, a top roller axis of the top roller can be supported on both sides in a top roller yoke attached to the top roller support. This ensures that the top roller axis is evenly loaded on both sides, preventing tilting of the top roller axis, even when a force is applied that is asymmetrical to the roller center.

[0019] The top roller axis of the top roller can be secured by means of a top roller lock in the top roller yoke, e.g., in a corresponding groove in the top roller yoke. The top roller lock is preferably manually removable. This allows for quick, tool-free replacement of the top roller. The top roller yoke can be attached to the top roller support so that it can be moved along the running direction of the fiber strand, allowing the top roller to be moved and fixed into a desired position relative to the bottom roller. This makes it possible to adjust a so-called leading or trailing edge of the top roller relative to the bottom roller. Templates can also be used here as positioning aids.

[0020] In some embodiments, the loading device may comprise a loading element, preferably a pneumatic or spring-loaded loading element, for example, selected from the group consisting of a pneumatic cylinder, air spring, coil spring, leaf spring, diaphragm cylinder, diaphragm pressure element, and bellows. A loading element may act on a single roller pair or on multiple roller pairs simultaneously.

[0021] In some embodiments, the loading device or the loading element on the loading arm can be moved and secured to various positions along the running direction of the fiber strand, so that a point of application of the load can be brought and fixed to a desired position on the top roller support by the loading device. In this way, the load application can be optimized. Depending on the position, the lever of the top roller support is enlarged or reduced. For each loading device, the force applied to the top roller can be individually adjusted.

[0022] In some embodiments, the loading device can comprise a convex loading head, wherein the loading head can be moved and secured to the top roller support in various positions along the running direction of the fiber structure, so that a point of application of the load can be brought and fixed by the loading device into a desired position relative to the top roller support. The convex loading head can be hemispherical, dome-shaped, or mushroom-shaped.

[0023] In some embodiments, the loading arm can be locked in a closed position without play. For this purpose, a fixed stop is preferably provided in the housing of the loading arm.

[0024] In some embodiments, the loading device can be moved into a loading position or a relief position when the loading arm is in the closed position. The loading devices of a drafting system can be moved into the loading position or the relief position individually or as a group.

[0025] In some embodiments, the point of action of the loading device can be offset from the center of the top roller along the top roller axis. In other words, the point of action of the loading device can be arranged asymmetrically relative to the center of the top roller on all roller pairs and offset to the same side along the top roller axis, thus increasing visibility and operability of the drafting system from one side. This increases visibility from the same side and leads to easier and faster inspection of the drafting systems during inspection rounds around the spinning machine.

[0026] In the described drafting system, the contact pressure of the roller pairs can be individually adjusted via the loading devices by, on the one hand, controlling the force of the loading elements and, on the other hand, moving the point of action of the loading device on the top roller support to the desired position.

[0027] Furthermore, one or more upper and / or lower rollers can be wrapped with an apron, as is already known in the prior art. In addition to being guided by the corresponding roller or counter-roller, the respective aprons can be guided by one or more additional guide elements.

[0028] Furthermore, the bottom rollers in the drafting system can be mounted either overhung or on both sides. Short explanation of the figures

[0029] The invention will be explained in more detail below using exemplary embodiments in conjunction with the drawing(s). They show: Fig. 1 a schematic side view of a drafting system; Fig. 2 a section of the drafting system from Fig. 1 ; Fig. 3 a sectional view of a top roller suspension with loading device; Fig. 4 a section of the drafting system with a loading device with movable loading head; Fig. 5 under (a) a loading device with movable loading head and under (b) a detailed view of Fig. 5(a) ; Fig. 6 a top view of a loading head; Fig. 7 a loading device with a loading element for several pairs of rollers. Ways to implement the invention

[0030] In Fig. 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, where precise positioning and loading of the roller pairs is essential due to the high spinning speeds. Fig. 2shows an excerpt Fig. 1 with a pair of rollers.

[0031] The drafting system 1 comprises several roller pairs arranged one after the other in a running direction A of a fiber strand, each pair comprising a top roller 3 and a bottom roller 4. Furthermore, the drafting system can 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 support 2a in the drafting system housing 2. As a rule, their positioning relative to the running direction A is adjustable and fixable.

[0032] Each top roller 3 is attached to a top roller support 30 that can pivot about a rotation axis 31. The rotation axis 31 runs parallel to the rotation axes of the rollers. The pivotable top roller support 30 is connected to the bearing block or the bottom roller support 2a of the bottom roller 4 or to the drafting system housing. To support the top roller 3, the top roller support 30 can have a top roller yoke 32 that is connected to the top roller support 30. This connection is designed such that the top roller yoke 32 can be moved relative to the top roller support 30 in the running direction A of the drafting system and can be fixed in the desired position. This allows precise positioning of the top roller 3 with respect to the bottom roller 4. In particular, a leading or trailing edge of the top roller 3 relative to the bottom roller 4 can be adjusted in this way. The displaceability is in Fig. 2 and Fig. 4 indicated by arrow C.

[0033] The upper roller yoke 32 loads the upper roller axis 34 on both sides so that a uniform contact pressure of the two rollers is achieved.

[0034] The rotational axis 31 of the upper roller support 30 can also be arranged further down than shown in the figures and closer to the rotational axis of the upper roller 3. Instead of the straight upper roller support 30 shown, an angled or curved upper roller support can also be used.

[0035] To hold the top roller 4 in the bearing of the top roller yoke 32, particularly when the top roller support 31 pivots out, the illustrated embodiment features a top roller retainer 33, e.g., in the form of a leaf spring, which acts on the top roller spindle 34. This can be easily released by hand, so that the top roller spindle 34 with the top roller 4 can be easily removed from the bearing on the top roller yoke 32. Other configurations of the top roller retainer 33 are also possible.

[0036] A loading arm 20 is arranged above the top rollers 4 and is pivotally connected to the drafting system housing 2 via a rotation axis 21. The rotation axis 21 also runs parallel to the rotation axes of the rollers. The loading arm 40 can be moved back and forth 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 this position by means of a locking device 23, so that it assumes a play-free and precisely defined position in the closed position.

[0037] A loading device 40 is arranged on the loading arm 20 for each pair of rollers. The loading device 40 serves to load a respective top roller 3. 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, a pneumatic cylinder, air spring, coil spring, leaf spring, diaphragm cylinder, diaphragm pressure element, or bellows). The loading head 42 ensures a precisely positionable point of action of the load from the loading device 40 on the top roller support 30. The load can be finely adjusted by shifting the point of action.

[0038] 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 support 30 in the running direction A of the drafting system. With this displaceability, the point of action of the loading element 41 relative to the top roller support 30 or the top roller 3 can be adjusted in order to achieve a fine adjustment of the contact pressure of the top roller 3 on the bottom roller 3 via the leverage of the top roller support 30. The displaceability is in Fig. 2 indicated by arrow B.

[0039] In Fig. 3A sectional view of a previously described top roller suspension with a loading device 40 is shown. The top roller axis 34 of the top roller 4 is mounted in the top roller yoke 32. The top roller yoke 32 is slidably and fixably attached to the top roller support 30. In the embodiment shown, a projection of the top roller yoke 32 is guided in a guide of the top roller support 30. The top 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.

[0040] The point of action of the load by the loading device 40 is arranged asymmetrically with respect to the center of the top roller 3 in all roller pairs and offset to the same side along the top roller axis 34, so that the visibility and operability of the drafting system from one side is increased.

[0041] Fig. 4shows a section of the drafting system with a further embodiment of a loading device. In contrast to the loading device of the Fig. 2 The convex loading head 42 can be attached to the upper roller support 31 in various positions along the running direction A of the drafting system and contacts the loading element 41 with the convex side. The previously described fine adjustment can be achieved by moving (arrow D) the loading head 42. This embodiment has the advantage that, when the lower roller support 2a is moved, the point of action of the load by the loading device 40 is not displaced relative to the upper roller support 31, and any further fine adjustment is not necessary.

[0042] Fig. 5(a)shows an embodiment of the loading device with a diaphragm cylinder as loading element 41. Furthermore, a convex loading head 42 which can be fastened to the upper roller carrier 30 at various positions is shown. Fig. 5(b) shows a larger detailed view Fig. 5(a) .

[0043] In this variant, the loading head 42 has two pins 43 on a bottom side opposite the convex side, which can be inserted into double holes 35 in the upper roller support 30. In order to position the loading head 42 at different locations, the upper roller support 30 has several evenly spaced double holes 35 (jumps). A plan view of the underside of the loading head is shown in Fig. 6 shown.

[0044] The pins 43 are offset by 1 / 4 of the distance between the double holes 35 from the axis of the load head 42. By inserting the load head 42 alternately into the double holes 35, rotated by 180°, the number of jumps can be doubled compared to the number of double holes 35. For visual control of the orientation of the load head 42, inclined surfaces can be formed on a base of the load head 42.

[0045] The convex side of the loading head 42 is spherical, dome-shaped, or mushroom-shaped, so that a diaphragm of the diaphragm cylinder can function entirely without a hard surface. The base of the loading head, or rather the lower roller support 2a, can be moved slightly without the diaphragm cylinder having to move along with it.

[0046] The pins can also be rectangular or oval, so that even with only one pin, independent rotation of the load head 42 is prevented.

[0047] To achieve a higher load, the diaphragm cylinder can be oval or elliptical.

[0048] Fig. 7 shows in contrast to Fig. 5 An embodiment of the loading device 40 with a membrane element as the loading element 41, which extends over several pairs of rollers. The membrane element can be tubular or sausage-shaped and acts on the loading head 42 of several pairs of rollers. The force can be individually adjusted by positioning the loading head 42 relative to the top roller support 30. List of designations

[0049] 1Drafting system 2Drafting system housing (supporting structure) 2aLower roller support 3Top roller 4Bottom roller 20Loading arm 21Loading arm rotation axis 23Loading arm locking mechanism 24Stop 30Top roller support 31Top roller support rotation axis 32Top roller yoke 33Top roller lock 34Top roller axis 35Double bore 40Loading device 41Loading element 42Convex loading head 43Pin AFiber direction BLoading element mobility CTop roller yoke mobility DLoading head mobility

Claims

1. A drafting system (1) for a textile machine, in particular an air-spinning machine, for drafting a strand-shaped fibre band fed to the drafting system, having a plurality of roller pairs arranged in succession in a running direction (A) of the fibre band, each having a top roller (3) and a bottom roller (4), and a weighting device for applying a load to the top roller (3) of the plurality of roller pairs; wherein the respective bottom roller (4) is mounted and held in a housing (2) of the drafting system (1), wherein the respective top roller (3) is mounted and held by means of a top roller carrier (30) which can be pivoted about a rotary axis, wherein the drafting system (1) further comprises a swivelling weighting arm (20) which can be brought into an open position and a closed position, and wherein the weighting arm (20) has an individually adjustable weighting device (40) for each roller pair, which applies a load to the respective pivotable top roller carrier (30) in a weighting position when the weighting arm (20) is closed, characterised in that the respective top roller (3) is mounted and can be positioned in the housing (2) of the drafting system (1) in a manner decoupled from the weighting device (40) and the weighting arm (20).

2. The drafting system according to claim 1, characterised in that the bottom rollers (4) are each mounted on a bottom roller carrier (2a) fixed in the housing (2).

3. The drafting system according to claim 2, characterised in that the bottom roller carrier (2a) can be displaced along the running direction (A) of the fibre band and can be fixed in a desired position.

4. The drafting system according to one of claims 2 or 3, characterised in that the pivotable top roller carrier (30) is connected to the bottom roller carrier (2) so that it can pivot about a rotary axis (31) of the top roller carrier (30).

5. The drafting system according to one of the preceding claims, characterised in that the rotary axis (31) of the top roller carrier (30) is arranged downstream or upstream of the roller pair in the running direction (A) of the fibre band, so that the top roller carrier (30) can be swung out in the running direction (A) or against the running direction (A).

6. The drafting system according to one of the preceding claims, characterised in that a top roller axis (31) of the top roller (3) is mounted at both ends in a top roller yoke (32) attached to the top roller carrier (30).

7. The drafting system according to claim 6, characterised in that a top roller axis (31) of the top roller (3) is secured in the top roller yoke (32) by means of a top roller safety device (33), which can preferably be released by hand.

8. The drafting system according to claim 6 or 7, characterised in that the top roller yoke (32) is attached to the top roller carrier (30) so that it can be displaced along the running direction (A) of the fibre band, so that the top roller (3) can be brought into a desired position relative to the bottom roller (4) and fixed in place.

9. The drafting system according to one of the preceding claims, characterised in that the weighting device (40) has a load element (41), preferably a pneumatic or springloaded load element selected, for example, from the group consisting of pneumatic cylinder, air spring, coil spring, leaf spring, diaphragm cylinder, diaphragm compression element, and bellows.

10. The drafting system according to one of the preceding claims, characterised in that the weighting device (40) or the load element (41) can be moved and mounted to the weighting arm (20) in various positions along the running direction (A) of the fibre band, so that a point of application of the load can be brought and fixed by the weighting device (40) to a desired position of the top roller carrier (30).

11. The drafting system according to any one of the preceding claims, characterised in that the weighting device (40) has a convex load head (42), wherein the load head (42) can be moved and mounted to the top roller carrier (30) in various positions along the running direction (A) of the fibre band, so that a point of application of the load can be brought and fixed by the weighting device to a desired position relative to the top roller carrier (30).

12. The drafting system according to one of the preceding claims, characterised in that the weighting arm (20) can be locked in a closed position without play.

13. The drafting system according to one of the preceding claims, characterised in that the weighting device (40) can be brought into a weighting position or a non-weighting position when the weighting arm (20) is in the closed position.

14. The drafting system according to claim 11, characterised in that the weighting devices (40) of a drafting system can be moved individually or in a group into the weighting position or the non-weighting position.

15. The drafting system according to one of the preceding claims, characterised in that the point of application of the load by the weighting device (40) is offset with respect to the middle of the top roller (3) along the top roller axis (34).