CN110249085B

CN110249085B - Circular comb with carding segment and alignment segment

Info

Publication number: CN110249085B
Application number: CN201880009769.6A
Authority: CN
Inventors: 弗雷德里希·海宁格尔
Original assignee: Staedtler and Uhl KG
Current assignee: Staedtler and Uhl KG
Priority date: 2017-02-02
Filing date: 2018-01-12
Publication date: 2022-03-01
Anticipated expiration: 2038-01-12
Also published as: DE102017201678B4; EP3577261A1; CN110249085A; JP7030130B2; DE102017201678A1; WO2018141532A1; EP3577261B1; JP2020505527A

Abstract

A circular comb (16) fastened to a shaft (14) of a carding machine (1), which shaft is rotatable about an axis of rotation (13) in a carding direction (26), the carding machine being configured to card textile fibres (2) and having fixed drawing rolls (7, 8, 9, 10) for carded textile fibres (11). The circular comb (16) comprises: a circular comb body unit (17) having an outer portion (18); a carding segment (19) having a plurality of carding bars (22) arranged on the outside (18) of the circular comb body unit (17), the carding bars being equipped with outwardly projecting carding teeth (23) such that their front carding tooth sides are each inclined in the carding direction (26) when viewed in the carding direction (26); and an alignment section (20) arranged in an outer portion (18) of the circular comb body unit (17) and provided with a plurality of outwardly protruding alignment members (25) such that front alignment member sides are each inclined oppositely to the combing direction (26) when seen in said combing direction (26) and some of them are arranged one behind the other when seen in the combing direction (26).

Description

Circular comb with carding segment and alignment segment

The present patent application claims priority from the German patent application DE 102017201678.8, the content of which is incorporated herein by reference.

Technical Field

The invention relates to a circular comb to be fastened to a shaft of a carding machine, which shaft is rotatable about a rotation axis in a carding direction, the carding machine being intended for carding textile fibres and having a stationary drawing roll for the carded textile fibres.

Background

Combs, which are used for example in carding machines and are configured as circular combs or circular combs, are known from the prior public use, wherein the carding elements are arranged on a circular comb body in order to engage the fiber tufts of the textile fibers to be carded. Combs provided with a comb element along at least a portion of their circumference are referred to as circular combs. The effective carding zone can be, for example, 78 °, 90 °, 111 ° or 137 ° of the circumference of the circular comb profile. The comb element may, for example, be configured as a needle, a needle bar, a saw-tooth wire portion, a comb tine, or, in particular, a saw-tooth cut. A plurality of these carding elements are usually pre-assembled to form carding bars, sometimes also referred to as comb fittings. A carding bar of this type may thus comprise a plurality of serrated cuts, serrated line portions, or also toothed shims provided with teeth which are arranged axially behind one another, i.e. in the direction of the axis of rotation.

The prior art carding machines operate at very high nip speeds, making the circular comb rotate up to 600 times per minute. Even higher pinch rates are also conceivable. These high operating speeds result in increased and sometimes new requirements to be met by the design and function of the carding machine and its components at their various locations. One of these problems relates to the joining or bonding of fibers carded in the current carding cycle to fibers carded in a previous carding cycle.

Document DE 68911552T 2 describes a carding machine comprising a circular comb, in which the portion of the fibres just carded and the portion of the previously carded fibres held by the drawing rolls will remain in their respective correct positions before and during the bonding process. For this purpose, edge control means are provided which are arranged behind the actual combing segment of the circular comb, as seen in the combing direction. The edge control member has a gap behind the carding segment for maintaining an air flow directed through the lower drawing roll and downwardly in the direction of the suction box, so that the already (in the previous cycle) carded fibre portion, which is fed back in the direction of the circular comb by the counter-rotation of the drawing roll performed as part of its backward movement, is pressed against the lower drawing roll. The edge control member also has a tip line surface on which the portion of freshly carded fibers fed by the nip assembly rests to prevent bending thereof. However, if this tip line surface moves away from the freshly combed fibres and is located opposite the lower pulling roll, the air flow directed downwards there is interrupted, which may result in already combed fibres being detached from the lower pulling roll (in the previous cycle), thus leading to an unsatisfactory bonding process.

Document EP 3034660 a1 describes a circular comb with an air baffle or air guide element which is arranged behind the comb segment of the circular comb, as seen in the combing direction. This guide member is provided to control the air flow so that the portion of (previously) carded fibers fed back by the pulling rolls rests on the lower pulling roll.

Furthermore, document EP 0447900 a1 describes a circular comb configured such that lateral guide bars are arranged at both axial front ends, as seen in the carding direction behind the carding segment, to prevent the fibers of the newly carded fiber portion fed by the nip assembly from spreading laterally. Furthermore, a fiber support section is provided on which the newly carded fiber portions fed by the nip assembly rest to prevent bending thereof.

Furthermore, document DE 102009032799 a1 describes another circular comb, which comprises a first and a second comb tooth segment region. The teeth of the second comb tooth segment region are configured such that the combing effect is lower than that at the end of the first comb tooth segment region arranged opposite to the direction of rotation.

Despite these known solutions, irregular and unsatisfactory results often occur in previous carding machines during the bonding process, especially when these carding machines are operated at high nip speeds.

Disclosure of Invention

The invention is therefore based on the following objects: a circular comb of the type mentioned at the beginning is provided, the properties of which are improved compared to previously known embodiments.

To achieve this object, a circular comb is provided. The circular comb according to the present invention has: a circular comb body unit having an outer portion; a carding segment having a plurality of carding bars arranged on the outside of the circular comb body unit and equipped with outwardly projecting carding teeth such that front carding tooth sides thereof are each inclined in a carding direction when viewed in the carding direction; and an alignment section equipped with a plurality of outwardly projecting alignment members and arranged on the outside of the circular comb body unit such that front alignment member sides thereof are each inclined with respect to the combing direction when seen in the combing direction, and some of which are arranged back and forth at least substantially when seen in the combing direction.

It has been found that at high operating speeds of the carding machine, at which the nip speed is as high as 600 revolutions per minute, both fibre portions (in other words, on the one hand the fibre portion to be initially carded and subsequently newly carded and, on the other hand, the portion of previously carded fibres held by the drawing roll) are exposed to considerable forces, which can generate air and/or fibre eddies and can therefore lead to irregularities during bonding (in other words, when joining together the two fibre portions) if no appropriate countermeasures are taken. In order to avoid this at least to the greatest possible extent, the circular comb according to the invention has an alignment section, wherein the alignment elements project in particular substantially radially outward.

The alignment member may, for example, be configured as an alignment tooth, an alignment pin, or the like. The alignment teeth may in particular have different tooth geometries and may preferably be integral components of a serrated cut, a serrated line portion or a serrated shim. As with the comb teeth, the alignment member is constructed of a metallic material and is preferably mechanically rigid.

According to the invention, these alignment elements each have a front alignment element side which is each inclined counter to the carding direction, in other words the alignment elements have in particular a negative element face angle or tooth face angle.

This is the difference between the alignment features and the comb teeth of the comb bar of the comb section. The comb teeth also project outwardly, in particular in a substantially radial direction, but have front comb tooth sides which are each inclined in the combing direction, in other words which have a positive tooth face angle. This positive flank angle may also be referred to as the tooth engagement angle. The required carding engagement of the carding teeth with the textile fibers, which are held in particular by the nip assembly and are still to be carded, is due to this positive tooth face angle. The combing teeth of the combing bar cover the combing circumferential angle range and form the actual combing area of the circular comb as a whole.

However, on the other hand, the alignment features do not require such a combing engagement. Specifically, the aligning members are arranged to align, guide, parallelize, stretch and/or especially hold the carded fibers fed back by the pulling rolls so as to rest on the lower pulling rolls. This does not require a positive combing engagement. A positive combing engagement may even be counterproductive. In fact, it is intended to contact the fed back and carded fibers relatively gently. This gentle fiber contact is due to, among other things, the negative part face angle or face angle of the alignment part. The alignment members are arranged on the outside of the circular comb body unit, in particular in a tangentially and preferably axially distributed manner, allowing the gentle fiber contact to preferably take place anywhere in the region of the alignment section. Due to the fact that some of the aligning members are arranged one behind the other as seen in the carding direction, this gentle fibre contact may preferably even occur several times per cycle (in other words, during one revolution of the circular comb). Overall, this results in a particularly effective alignment, guiding, stretching and/or parallelization of the fed back and carded fibers. Furthermore, this ensures good contact of the fibers with the lower pulling roll. This ensures a very uniform bonding process even at the high machine speeds mentioned above, resulting in a uniform fibre top (i.e. carded, aligned fibres which are laid in an overlapping manner on the drawing roll). These fibers can be processed into high quality yarns with much lower yarn errors (thick and thin places). As a result, a yarn with a low CV value, which is an index of yarn uniformity, is obtained.

Furthermore, the circular comb with the aligning section according to the invention allows to achieve a very high nip speed of the carding machine while ensuring a constant high quality of the fibrous structure on top of the carded fibers. A pinch rate of up to 600 revolutions per minute or even higher running speeds are possible. Furthermore, due to the design of the alignment section, the alignment section is cheap to manufacture, which is especially similar to the design of the carding section.

In the simplest case, the circular comb body unit of the circular comb according to the invention can be formed by a one-piece circular comb body. However, the one-piece circular comb body may also comprise a multi-part circular comb body. Furthermore, the one-piece circular comb body can have additional optional members, such as in particular fastening brackets, to fasten the circular comb to the shaft of the carding machine. The circular comb body unit or at least the circular comb body itself can in particular have the basic shape of a circumferential section of a hollow cylinder, wherein the cylinder axis of the hollow cylinder is a longitudinal center axis of the circular comb body unit, in particular coinciding with the rotational axis. Thus, the outer portion of the circular comb body unit is preferably also at least substantially in the shape of a pitch cylinder. This applies in particular to the region in which the carding segment is arranged; however, this may also be applied to the region where the alignment section is provided. The outer portion of the circular comb body unit can also have a different geometry from the exact pitch cylinder shape, in particular, immediately in front of the alignment section or in the region of the alignment section. Although this geometry may differ from a precise pitch cylinder shape, the outer portion may in general be interpreted as a tangential outer portion or outer circumferential side, among other things.

The position or orientation terms used here each refer inter alia to the axis of rotation of the shaft or to a cylindrical coordinate system defined by this axis of rotation. In this context, the term "axial" refers to an orientation in the direction of the axis of rotation, the term "radial" refers to an orientation perpendicular to the axis of rotation, and the term "tangential" refers to an orientation in the circumferential direction with respect to the axis of rotation. The combing direction of the circular comb according to the invention is in particular the direction of rotation of the circular comb about the axis of rotation. The combing direction is in particular one of two circumferential directions around the axis of rotation.

The expression "textile fibers" as used herein refers in particular to wool fibers, cotton fibers, synthetic fibers, chemical fibers or fibers composed of a mixture of at least two of the aforementioned fiber types.

The following are advantageous embodiments of the circular comb according to the invention.

In an advantageous embodiment, the negative part face angle of the alignment part is in the range between-5 ° and-65 °, in particular between-5 ° and-40 ° and preferably between-8 ° and-30 °. In this case, the effect of the alignment members on the carded fibre portion fed back by the pulling roll is very effective but not too strong.

According to a further advantageous embodiment, the alignment member has a protrusion in a range between 0.5mm and 4mm, in particular between 0.8mm and 2.5mm and preferably between 1.5mm and 2 mm. The (free) protrusion, in particular the part of the alignment member, protruding beyond the base region has a radial dimension. For example, if the alignment member is configured as an alignment tooth, this may be a tooth height. Said dimensions of the protrusions are also chosen such that the effect exerted by the alignment member on the carded fibre portion fed back by the pulling roll is very effective but not too strong.

According to a further advantageous embodiment, the aligning section is arranged behind the comb section, and in particular directly adjoins the comb section, as seen in the comb direction. As a result, a circular comb of small construction volume is obtained. Furthermore, arranging the aligning section and the carding section in direct abutment with each other preferably prevents impurities, such as dust, fibre particles, etc., from accumulating between said sections. These impurities may separate and enter the carded fibers. Furthermore, it is advantageous that the transition between the comb section and the alignment section is substantially continuous, in other words in particular without any substantial interruptions and/or steps, since these may allow vortex formation.

According to a further advantageous embodiment, the alignment members each have an alignment tip, and at least some of the alignment tips have a smaller distance, in particular a radial distance, from the axis of rotation than the combing tips of the combing teeth. The comb teeth lie in particular on a common circumferential surface which forms a cylindrical comb envelope, the alignment tip being in particular configured such that it does not reach the comb envelope. The position of the alignment tip is in particular below the carding envelope or in the interior space enclosed by the carding envelope. The radial distance between the alignment tip and the carding envelope is in particular in the range between 0.5mm and 9mm, preferably between 0.5mm and 6mm, more preferably between 1mm and 4 mm. The aforementioned distances each apply to at least some of the alignment tips. However, the distance may also be particularly applicable to all alignment tips. This distance preferably ensures that there is always an air flow directed downwards through the lower pulling roll, resulting in a close contact between the carded fibre portion fed back by the pulling roll and the lower pulling roll. Due to said distance, said air flow is advantageously provided even if the alignment member has just moved past the portion of carded fibres fed back by the pulling roll. By correspondingly setting the radial distance between the aligning tip and the carding envelope, and in particular by setting the (free) projections of the aligning member, it is possible to adjust the fibrous material to be treated. The fibrous material to be treated can vary, for example, in terms of its weight, number and also in terms of the length of the textile fibers to be carded contained therein. In this context, it is particularly advisable to choose a larger value for the radial distance between the aligning tip and the carding envelope when processing long (i.e. longer) fibers, in order to prevent an excessive influence or effect on the carded fiber portion fed back by the drawing roller during its return movement. Otherwise, these substantially high quality fibers may tear from the nip between the pulling rolls and ultimately enter the waste disposal system.

According to a further advantageous embodiment, the radial distance between the axis of rotation and the alignment tip of the alignment part decreases, in particular, counter to the combing direction. Correspondingly, the radial distance between the aligned tip and the combing envelope increases opposite to the combing direction. The radial distance between the alignment tip and the combing envelope, which increases counter to the combing direction, is in particular in the range between 0mm and 14mm, preferably between 0.5mm and 14mm and more preferably between 2mm and 8 mm. This increased radial distance also facilitates the movement of the air flow downward over the lower pull roll. The radial distance between the aligning tip and the carding envelope also allows, in particular, to set the force exerted by the aligning member on the carded fibre portion fed back by the drawing roll. This force exerted on the fed back fibers may initially (in other words at the beginning of each cycle of the influence exerted by the alignment members on these fibers) be even greater even when the fibers are initially well gripped between the pulling rolls. This fiber clamping force decreases with increasing path length of the fiber being fed back, so the fed back fiber should be exposed to a reduced force especially later. This type of reduction force is generated in the following manner: so that the radial distance between the alignment tip and the combing envelope increases opposite to the combing direction.

According to a further advantageous embodiment, between the alignment members arranged adjacent to each other in the direction of the axis of rotation there is a respective free gap, in other words in particular in the axial direction, so that a respective free passage is formed between the rows of alignment members, which are arranged one behind the other in the carding direction or at an angle to the carding direction. This measure also facilitates the movement of the air flow flowing downwards over the lower drawing roll. Furthermore, it allows to adjust the fibrous material to be treated, in particular in terms of the fineness, length and/or number of the textile fibers contained in the fibrous material, so as to optimize the result of the bonding process.

According to a further advantageous embodiment, the ratio of the passage area of the free passage to the cross-sectional area perpendicular to the carding direction of the protruding portion of the alignment member is in the range between 0.17 and 4, in particular between 0.25 and 1.5 and preferably between 0.33 and 1. Thus, a free passage is also formed in the alignment section itself, which is large enough to allow or facilitate the movement of the air flow downward through the lower pulling roll.

According to a further advantageous embodiment, the passage area of the free passage varies, in particular decreases continuously, counter to the carding direction. There is then still sufficient free passage for the air flow to pass down the lower roll. Moreover, in particular, the effective contact surface is increased, by means of which the alignment members can contact the portion of the carded fibers fed back by the drawing rolls to achieve the desired orientation, guiding, stretching and/or parallelization. In particular, a further effect of this measure is that the aligning effect at the end of the aligning section opposite to the carding direction is also slightly increased, in order to be able to influence even the last remaining fibers that have not been aligned yet.

Drawings

Further features, advantages and details of the invention will emerge from the following description of exemplary embodiments, which is given with reference to the accompanying drawings, in which

FIG. 1 shows an exemplary embodiment of a carding machine, including a circular comb having a carding segment and an alignment segment,

figure 2 shows an enlarged view of section II of the circular comb as shown in figure 1,

FIG. 3 shows a cross-sectional view of the cross-section III as shown in FIG. 2 of the alignment bar of the circular comb as described in FIGS. 1 and 2, an

Fig. 4 to 7 show exemplary embodiments of other circular combs, each having aligned segments, for use in a carding machine as shown in fig. 1.

Detailed Description

Mutually corresponding parts are denoted by the same reference numerals in figures 1 to 7. Details of exemplary embodiments taken alone and explained in more detail below may also form part of the invention or the patentable subject matter.

Fig. 1 shows an exemplary embodiment of a carding machine 1 for carding textile fibres 2, said figure only showing some components of this carding machine 1. Wherein the carding machine has a nip assembly 3 with an upper nip 4 and a lower nip 5 for feeding textile fibres 2 to be carded. The upper and

lower pinchers

4, 5 can be opened and closed during a carding cycle (pinching cycle). In fig. 1, the open state is shown. The nip assembly also performs relative movements with respect to other machine components of the card 1, in particular with respect to the separating unit 6 comprising the fixed drawing rolls 7, 8, 9 and 10. The drawing rolls 7 to 10 are arranged in pairs. The pulling rolls are used to receive and discharge the textile fibres 2 after carding. The carded textile fibres are here denoted by reference numeral 11.

For carding the textile fibres 2, two carding elements are provided, namely, on the one hand, a top comb 12 fastened to the gripper assembly 3, and, on the other hand, a circular comb 16 fastened to a shaft 14 rotatable about an axis of rotation 13, in particular by means of a one-piece or multi-piece mounting unit 15. The axis of rotation 13 can also be interpreted in particular as the longitudinal center axis of the circular comb 16. A cylindrical coordinate system is defined with respect to the rotation axis 13 with an axial direction z oriented along the rotation axis 13 (see fig. 3), wherein the radial direction r is oriented along a distance direction with respect to the rotation axis 13 and the tangential direction Φ is oriented along a circumferential direction around the rotation axis 13.

The circular comb 16 has various component parts. The circular comb has a circular comb-shaped body 17 with a comb section 19 and an alignment section 20, each fastened to its exterior 18 by means of a fastening strip 21, wherein in particular a dovetail groove geometry and/or a T-groove geometry is suitable. Alternatively, it may be fastened by gluing, pressing and/or clamping. Carding segment 19 is made up of a plurality of carding bars 22 fastened to outer portion 18. In the exemplary embodiment shown, a total of four carding bars 22 are provided, which are formed by saw-tooth cuts arranged one behind the other in the axial direction (in other words in the direction of the axis of rotation 13), with carding teeth 23 projecting radially outwards. The integral carding bar 22 covers the carding circumferential angle, which forms the effective carding area and may for example take values of 78 °, 90 °, 111 °, 137 ° or 180 °, and other values from the range between 75 ° and 150 °. In the exemplary embodiment shown comprising four carding bars 22, the carding circumferential angle covers an angular range of about 90 °.

The alignment section 20 also has a plurality of component parts, namely three alignment bars 24 in the exemplary embodiment shown (which are similar to the carding bars 22), which are formed by arranging sawtooth-shaped cutouts with radially outwardly projecting alignment teeth 25 one behind the other in the axial direction.

In the exemplary embodiment of the circular comb 16 shown in fig. 1, the alignment section 20 directly adjoins the carding section 19. The aligning section 20 is arranged behind the carding section 19 in the carding direction 26, wherein the shaft 14 and thus the circular comb 16 fastened thereto rotate about the axis of rotation 13. The carding direction 26 corresponds to the tangential direction phi.

A suction box cover 27 adjoins the separating unit 6 from below, said suction box cover 27 enclosing in particular the largest part of the circular comb 16.

The carding bars 22 of the carding segment 19 are provided with a respective cover plate at each of their two axially forward ends. In order to illustrate the design of the carding bars 22, the cover plates of the carding bars 22 adjoining the aligning section 20 have been omitted in the views of fig. 1 and 2. This provides a better understanding of the design of the comb teeth 23 of the comb bar 22, and in particular the design of the comb tooth arrangement and orientation.

As shown in the enlarged detail view of section II highlighted in fig. 1 shown in fig. 2, the comb teeth 23 are distinct from the alignment teeth 25. The comb teeth 23 each have a front comb tooth side 28 which is inclined in the comb direction 26, in other words which has a positive tooth face angle ZK with respect to the radial direction r. In contrast, the alignment teeth 25 each have a front alignment flank 29, which is inclined oppositely to the carding direction 26, in other words which has a negative face angle ZA with respect to the radial direction r. In the exemplary embodiment shown, face angle ZA of alignment tooth 25 has a value of-10.

As can also be seen from the detail view of fig. 2, the alignment teeth 25 protrude by means of a protrusion V beyond the bottom of the zigzag slit strip. In the exemplary embodiment shown, this protrusion V is 1.75 mm.

While rotating about the axis of rotation 13, the combing tip 30 of the combing teeth 23 moves on a cylindrical combing envelope 31. In contrast, the alignment tips 32 of the alignment teeth 25 do not reach this combing envelope 31. Between the aligning tip 32 and the combing envelope 31 there is a free gap, the radial extent D of which in the exemplary embodiment shown in fig. 1 and 2 is always not equal to zero and also increases counter to the combing direction 26. Thus, the radial distance of the alignment tip 32 from the axis of rotation 13 is smaller than the carding tip 30. In the exemplary embodiment shown, the extension D (radial distance) increases from the first 3mm to 6mm opposite the combing direction 26.

Fig. 3 shows a cross-sectional view of one of the alignment bars 24 in the direction of the axis of rotation 13 (in other words, perpendicular to the carding direction 26). This cross section is highlighted by III in fig. 2. Fig. 3 shows three zigzag-shaped cut-out strips arranged axially one behind the other in the direction of the axis of rotation 13, which are each provided with an alignment tooth 25 projecting radially outwards. Between the zigzag-cut strips, intermediate spacers 33 are arranged such that free channels 34 are formed in each case between axially adjacent alignment teeth 25. These free channels 34 each have a channel area E, which in the exemplary embodiment shown is 1.25 times the cross-sectional area F of one of the alignment teeth 25 oriented perpendicularly to the carding direction 26, and as the case may be, may be part of the bottom of the zigzag slit band. The cross-sectional area F includes a portion of the base of the respective alignment tooth 25 and, as the case may be, may be a portion of the base of the zigzag slit strip disposed between the alignment tip 32 of the alignment tooth 25 and the upper edge of the middle pad 33. In the detail view shown in fig. 3, the two relevant areas E and F are each highlighted with a different hatching.

In the exemplary embodiment shown, the passage area E of the free passage 34 remains constant in the carding direction 26. In an alternative exemplary embodiment, not shown, the passage area E of the free passage 34 decreases continuously counter to the carding direction 26.

The function of the circular comb 16, and in particular the alignment section 20, will be described in more detail below.

The carding machine 1 is operated at a high nip speed of the circular comb 16, for example 600 revolutions per minute. As a result, the resulting high forces are exerted on the textile fibers 2 still to be carded, but also on the carded textile fibers 11. The aim is to avoid the adverse consequences resulting therefrom. One countermeasure is the alignment section 20, which affects, among other things, the carded textile fibers 11. In order to receive and discharge the carded textile fibres 11, the drawing rolls 7 to 10 of the separating unit 6 perform a backward movement. In order to discharge the carded textile fibers 11, the drawing rolls 7 to 10 are rotated in their respective forward direction. Before accommodating a new portion of carded textile fibers 11 fed by the movable nip assembly 3 and the top comb 12 fastened thereon, the drawing rolls 7 to 10 are rotated slightly in opposite directions, so that the previously accommodated carded textile fibers 11 are fed back a little from the first pair of mutually opposed drawing rolls 7 and 8. Next, a new portion of carded textile fibers 11 fed by the nip assembly 3 and the top comb 12 is placed on this fed back portion of carded textile fibers 11 during the next forward rotation of the drawing rolls 7 to 10 and bonded thereto.

For optimum performance of this joining or bonding process, it is important that the portion of carded textile fibres 11 fed back by the drawing rolls 7 to 10 rest as closely as possible on the first lower drawing roll 7. This condition is not always satisfied due to the high operating speed of carding machine 1. There are the following cases: the fed back portion of the carded textile fibres 11 is separated from the first lower drawing roll 7, causing these carded textile fibres 11 to swirl. This is undesirable. Accordingly, the circular comb 16 is provided with the aligning section 20 to offset such an influence. The aligning teeth 25 of the aligning section, the front aligning tooth flanks 29 of which are inclined counter to the carding direction 26, ensure that the portion of carded textile fibres 11 fed back by the drawing rolls 7 to 10 is guided, aligned, stretched, homogenized and/or parallelized. In particular, another effect of the aligning section 20 is that this feed-back portion of the carded textile fibres 11 rests as close as possible on the first lower drawing roll 7, allowing this feed-back portion to be easily connected or joined to a new containing portion of the carded textile fibres 11.

This is facilitated by the negative face angle ZA of the alignment tooth 25. The negative face angle ZA of the aligning teeth ensures gentle contact of the fibers of the fed back portion of the carded textile fibers 11. There is no combing engagement. In particular, the fibers of the fed-back portion of the carded textile fibers 11 are not subjected to a traction force comparable to the traction force generated by the positive face angle ZK during the carding engagement of the carding teeth 23 with the textile fibers 2 still to be carded. The less flexible contact with the feed back portion of the carded textile fibres 11 is also due to the greater distance from the aligning tip 32. Furthermore, the radial distance D between the aligned tips 32 and the carding envelope 31 and the free channel 34 serve to maintain an air flow 34a through the first lower drawing roll 7 in the direction of the suction box cover 27. Overall, this ensures the desired close contact of the fed back portion of the carded textile fibres 11 with the first lower drawing roll 7.

Fig. 4 shows another exemplary embodiment of a circular comb 35 for a carding machine 1. The circular comb 35 has the same beneficial effects as described above for the fed back portion of the carded textile fibres 11 as the circular comb 16. The most important difference with the circular comb 16 is that the circular comb 35 has a two-part circular comb body 36, consisting of a first body part 37 and a second body part 38, the comb segment 19 being fastened to the first body part and the alignment segment 20 being fastened to the second body part. The two-piece circular comb body 36 can also be interpreted as a circular comb body unit comprising a first body part 37 and a second body part 38.

The further exemplary embodiment of the circular comb 39 shown in fig. 5 again has the same advantageous effect as the feed-back portion of the carded textile fibres 11. Like the circular comb 16, the circular comb 39 has only a one-piece circular comb body 40. The most important difference is that the alignment tips 32 of the alignment teeth 25 are arranged at an equal constant distance D from the comb envelope 31 in each circumferential position covered by the alignment section 20. In the exemplary embodiment shown, this radial distance D is 2.5 mm.

In a further alternative exemplary embodiment of a circular comb 41 of a carding machine 1 shown in fig. 6, a one-piece circular comb body 42 is provided, wherein a non-equipped free intermediate region 43 is provided on the outside 18 of the circular comb body between the carding segment 19 and the aligning segment 20. The outer portion 18 further has a stepped region 43a such that the partial contact surface 44 of the circular comb body 42 provided for the aligning section 20 has a smaller radial distance from the axis of rotation 13 than the partial contact surface 45 of the circular comb body 42 on which the comb bars 22 of the comb section 19 rest. In this exemplary embodiment, the radial distance D between the aligning tip 32 and the combing envelope 31 is also constant in the circumferential or combing direction 26.

Fig. 7 shows an exemplary embodiment of another circular comb 46, which is also intended to be installed in a carding machine similar to carding machine 1. The design of the circular comb 46 differs from the circular combs 16, 36, 39 and 41 described above in that

fastening brackets

48 and 49 are provided at both circumferential ends of the circular comb body 47, which in this case is configured as a single piece, to fasten the circular comb 46 to the shaft of a corresponding carding machine (not shown in detail in fig. 7). The fastening brackets 48 arranged behind the comb section 19 of a plurality of comb bars 22 in the comb direction 26 are equipped at their tangentially outer portion 50 with aligning pins 51 projecting outwards at an angle to the radial direction. The aligning needle 51 is inclined opposite to the carding direction 26. Thus, each of the aligning pins 51 has a partial area of its circumferential surface so that a front aligning side having a slope opposite to the combing direction 26 is formed when seen in the combing direction 26. Thus, the alignment pins 51 each have a negative face angle ZA and may vary in size, in particular in the carding direction 26. Basically, a uniform constant negative face angle ZA can be envisaged for all alignment pins 51. Furthermore, all needle tips 52 of the alignment tips 51 each have a radial distance D from the carding envelope 31 that is not zero. Also, a free passage is provided between axially adjacent alignment pins 51. In general, the circular comb 46 also provides an advantageous aligning effect exerted on the feed-back portion of the carded textile fibers 11, as described above for the circular combs 16, 35, 39 and 41. The one-piece circular comb body 47 and the two

fastening brackets

48, 49 form a circular comb body unit, on the outside of which, in addition to the comb section 19, a comb section 35 is arranged. In the exemplary embodiment shown in fig. 7, the comb section 35 is formed by a registration pin 51.

The alignment pins 51 of the circular comb 46 and the alignment teeth 25 of the circular combs 16, 35, 39, and 41 may be grouped into the general term "alignment feature". There are various possibilities for designing the alignment feature. The above embodiments are shown in fig. 1 to 7 with the alignment features configured as alignment teeth 25 as members of a saw-tooth cut and as alignment teeth 51 (for example only). Therefore, the alignment tooth may also have other geometries as long as the face angle ZA of the leading alignment flank 29 of the alignment tooth is negative with respect to the radial direction r. In turn, a favorable alignment effect on the portion of carded textile fibers 11 fed back by the separation unit 6 is obtained.

Claims

1. Circular comb to be fastened to a shaft (14) of a carding machine (1), which shaft is rotatable about a rotation axis (13) in a carding direction (26), which carding machine is configured to card textile fibres (2) and has a fixed drawing roll (7, 8, 9, 10) for the carded textile fibres (11), which circular comb has:

a) a circular comb body unit (17; 36; 40; 42; 47, 48, 49),

b) a carding segment (19) having a plurality of carding bars (22) arranged in the circular comb body unit (17; 36; 40; 42; 47, 48, 49) being equipped with outwardly projecting carding teeth (23) such that front carding tooth sides (28) of a carding bar, as seen in the carding direction (26), are each inclined in the carding direction (26),

it is characterized in that the preparation method is characterized in that,

c) in the circular comb body unit (17; 36; 40; 42; 47, 48, 49) on which an alignment section (20) is arranged, which alignment section is equipped with a plurality of outwardly projecting alignment members (25; 51) such that front alignment part sides (29) are each inclined oppositely to the carding direction (26) when seen in the carding direction (26), and some of the front alignment part sides are arranged one behind the other when seen in the carding direction (26).

2. A circular comb according to claim 1, wherein the negative part face angle (ZA) of the alignment part (25; 51) is in the range between-5 ° and-65 °.

3. Circular comb according to claim 1 or 2, characterized in that the projections (V) of the alignment members (25; 51) are in the range between 0.5mm and 4 mm.

4. A circular comb according to claim 1, wherein the aligning section (20) is arranged behind the comb section (19) as seen in the comb direction (26).

5. A circular comb according to claim 1, wherein the aligning section (20) directly adjoins the carding section (19).

6. A circular comb according to claim 1, characterized in that the alignment members (25; 51) each have an alignment tip (32; 52) and at least some of the alignment tips (32; 52) are at a smaller distance from the axis of rotation (13) than the combing tips (30) of the combing teeth (23).

7. A circular comb according to claim 1, characterized in that the distance between the axis of rotation (13) and the alignment tip (32; 52) of the alignment member (25; 51) decreases counter to the combing direction (26).

8. A circular comb according to claim 1, characterized in that there is in each case a free gap between the aligning members (25; 51) adjacent in the direction of the axis of rotation (13), so that in each case a respective free channel (34) is formed between the rows of aligning members (25; 51), which are arranged one behind the other in the carding direction (26) or at an angle to the carding direction (26).

9. A circular comb according to claim 8, wherein the ratio of the passage area (E) of the free passage (34) to the cross-sectional area (F) of the projection of the aligning member (25; 51) perpendicular to the carding direction (26) is in the range between 0.17 and 4.

10. Circular comb according to claim 8, characterized in that the passage area (E) of the free passage (34) decreases continuously counter to the combing direction (26).