EP2718489B1 - Guiding element in a clamping assembly of a combing machine - Google Patents

Description

The invention relates to a nipper unit of a combing machine, with a lower pliers plate, which can form a nip with a movable in the nipper unit upper pliers plate in the region of their pliers lip and a within the nipper unit above the lower pliers plate rotatably mounted feed roller, wherein the nipper unit at least a, mounted in the machine frame Abreisszylinder to form a tear-off is arranged downstream and with a, between the feed roller and the pliers lip on the lower pliers plate removably mounted and aligned transversely to the conveying direction of the fiber mass web, below the lower pliers plate rotatably mounted circular comb for combing out of fiber tufts is arranged.

In practice, it is necessary to adjust the combing on the comber portion (called "noils") as needed. The proportion of noil varies between 5 and 30% and as a rule depends on the desired yarn quality, which results from the subsequent spinning out of the combed fiber mass. In addition, the proportion of noil depends on the fiber mass presented (material template).

That with a high level of combing out, the long fibers remain in the combed fiber mass, while the short fibers almost completely reach the outflow of the noils. Very fine yarns can then be produced with these long fibers, since substantially fewer fibers are required in the cross section of the yarn, without the necessary yarn strength being impaired. Of course, a high proportion of noils has a direct effect on the production volume, which ultimately influences the earnings of the spinning mill directly. Therefore, it is necessary for the spinning master to find a balance between the required quality of the yarn and the loss of production due to the combed-out portion. As a result, the choice of the Auskämmungsgrades has a very great importance.

When combing out, it must therefore be ensured that the selection of the fibers can be carried out exactly.

In order to be able to adjust the combing machine, or their combing devices to a suitable combing, various methods are known.

One method is the adjustment of the Ecartement, which marks the distance between the pliers lip of the lower tong plate and the terminal point of the tear-off cylinder. A large Ecartement results in a high Auskämmung, while a small Ecartement a small Auskämmung is achieved. To adjust the Ecartement the coupling is rotated on the forceps shaft, so that the position of the swinging movement, or the pivoting of the pliers changed by a corresponding amount, whereby the Ecartement is larger or smaller depending on the adjustment. Furthermore, it is possible to influence the proportion of combing through the choice of food type of the feed cylinder. If the supply amount is supplied in the flow of the pliers (flow supply) from the feed cylinder, the combing is smaller than if this was done in the return of the pliers (return feed). As with the return feed the round comb combing out the full supply amount is present also the combed portion is greater than in the supply feed.

It is also known to provide a mixed feed, wherein a portion of the feed amount in the fore and the remainder is fed in the return.

Mixed forms are also possible, whereby the combing is adjusted with the choice of the type of food and the ecartement.

In the known measures described above, good results can sometimes be achieved, but again and again short fibers get into the combed fleece, which adversely affect the desired quality. This circumstance arises in particular when one has to work with a large ecartement in order to increase the amount of noil. As soon as the distance between the clamping point of the tear-off cylinders and the pliers is increased, the tear-off distance, or the length of the fiber mass participating in the drawing process, also increases during the tear-off process. The larger this length, the more floating (short) fibers are in this area. These floating fibers are uncontrolled. Thus, it is indefinite whether these fibers are now taken during the tearing process (which is synonymous with a stretching process) or whether they retained be combed out of the circular comb during the subsequent Auskämmvorgang.

In the published EP-1 449 944 A1 Therefore, a device has been proposed, wherein a web above the lower pliers plate between the feed trough of the feed roller and the nip of the nipper lip was attached to influence the Auskämmung. With this device it is possible to influence the combing without changing the ecartement. To change the combing, the bridge can be exchanged for another with a different geometry. That is, the bridge is mounted removable. From the publication of an embodiment is known, wherein the web is provided in the region of the side guides with through holes through which screws protrude over which the web is screwed against the lower pliers plate. In the middle region of the bridge, however, no attachment to the tong plate is provided. Since the conventional forceps plates can have a width of up to 300 mm, there is a risk that the bridge in the central region is therefore not completely seated on the forceps plate and there can accumulate fiber material. To eliminate this circumstance, therefore, the web was additionally glued in this central area with the pliers plate. However, this disassembly is limited and worsened. Since the existing space in the front region of the nipper unit (in short: pliers called) for the disassembly and assembly of the web is very limited, the accessibility for mounting the screw is very limited. Ie. The time required for the exchange of webs on a machine with the known solution may be significant and leads to production losses.

It is therefore the object of the invention to avoid the disadvantages of the known design and to propose a bridge, which can be dismantled and mounted quickly and without special aids and optimal system is guaranteed in its entire length on the lower pliers plate.

This object is achieved in that it is proposed that the web in the region of its support surface, which a bearing surface, one at least partially is made of ferromagnetic material lower pliers plate facing, having magnetic means and means are provided in the region of both ends of the web, via which the web is positively fixed in the plane of its support surface on the lower pliers plate. Thus, on the one hand the bridge can be placed accurately and quickly during installation on the positive elements and on the other hand, the web is held in this position by the magnetic means on the ferromagnetic lower tong plate. The magnetic means may consist of several means, which are mounted on the entire length of the web (ie also in the middle region of the web). Thus, the system of the bridge is guaranteed on the lower pliers plate over its entire length. The lower tong plate is at least in the area of a ferromagnetic material in which the web is mounted.

It is further proposed that the magnetic means - seen in the longitudinal direction of the web - consist of several spaced apart, fixed to the web magnet. Thus, the necessary number of magnets can be set, which are necessary to keep the bridge securely on the lower pliers plate even at high dynamic influences, which, for. B. occur in a reciprocating pliers. Also, this ensures the complete abutment of the web on the pliers plate also in the middle region, whereby the fiber material can not adhere.

Preferably, the magnets are mounted in recesses of the web.

Furthermore, it is proposed that the web in the region of its two ends has projections which point in the direction of the support surface of the lower pliers plate and protrude into recesses of the lower pliers plate and form a positive connection with these. Thus, the bridge during its installation can be easily transferred over the elevations in the recesses of the pliers plate and is then fixed in this position by the positive locking securely in its mounting position to the pliers plate. In the vertical direction to the lower tong plate the web is held on the magnets on the tong plate.

In order to achieve the same effect, a further embodiment is possible, wherein it is proposed that the bearing surface of the lower tong plate elevations has, which protrude into recesses of the web in the region of its two ends and form a positive connection with these. This represents a reverse type of attachment of the positive connection parts with the same effect as described above.

For lateral guidance of the guided over the web fiber material is proposed that the web is provided in the region of its two ends with, from its guide surface, upwardly projecting side guides for the fiber material.

To easily attach the side guide and the survey (which may be designed as a bolt) on the web, it is proposed that the respective side guide is connected to the respective elevation and the web in this area has an opening through which at least a portion of the respective Survey and / or at least a part of the respective side guide protrudes.

The term "respective" survey, or side guide refers to each one of the survey, or the side guide which is attached to the respective end of the web. In order to prevent falling out of the web from its installation position during operation, it is proposed to mount the feed roller in its installed position, or to dimension it, so that a release of the positive connection of the web with the lower tong plate is prevented. This ensures that the bridge remains in its installed position during operation even at high dynamic loads.

This blocking can be achieved by the corresponding design of the side guides, which face at least on one side of the feed roller. It is proposed that the side guides on the side opposite to the feed roller are each provided with an arcuate surface which, in the installed position, has a spacing of between 0.1 and 2.5 mm from the circumferential surface of the feed roller.

Preferably, the web (32) in the region of the guide surface (35) has a trapezoidal cross-section.

Further advantages will become apparent from the following exemplary embodiments

Fig.1

eine schematische Seitenansicht einer bekannten Kämmmaschine im Bereich des Zangenaggregates.

Fig.2

eine schematische Seitenansicht einer weiteren bekannten Kämmmaschine im Bereich des Zangenaggregates

Fig.3

eine schematische Teilansicht des Zangenaggregates nach Fig.1 oder Fig.2 in geschlossener Stellung mit einer erfindungsgemässen Anbringung eines Steges

Fig.4

eine vergrösserte Teilansicht nach Fig.3

Fig.5

eine Schnittdarstellung B-B nach Fig.4

Fig.5a

eine weitere Ausführungsform der Anbringung des Steges nach Fig.5

Fig.5b

eine Teilansicht Y nach Fig.5

Show it:

Fig.1

a schematic side view of a known combing machine in the region of the nipper unit.

Fig.2

a schematic side view of another known combing machine in the region of the nipper unit

Figure 3

a schematic partial view of the nipper unit after Fig.1 or Fig.2 in the closed position with an inventive attachment of a web

Figure 4

an enlarged partial view Figure 3

Figure 5

a sectional view BB after Figure 4

5a

a further embodiment of the attachment of the web after Figure 5

5 b

a partial view Y after Figure 5

FIG. 1 shows a known nipper unit 1 (called "pliers" for short), which is pivotally mounted on the crank arms 2, 3. In this case, two crank arms 2 are each mounted laterally of a circular comb 4 on the circular comb shaft 5 pivotally.

The circular comb 4 has a comb segment 7 on a part of its circumference. The other end of the pivot arms 2 is rotatably mounted on a clamp frame 8. The rear pivot arm 3 (there may also be two) is rotatably mounted on a gun shaft 10. The opposite free end of the pivot arm 3 is rotatably connected via a shaft 9 with the clamp frame 8. In general, several combing heads are arranged side by side on a combing machine, each combing head having a nipper unit. In the examples, however, the inventive attachment of a web is shown and described only on a single nipper unit.

The forceps 1 consists essentially of a fixed to the forceps frame 8 lower pliers plate 12 and an upper pliers plate 14 (sometimes called also pliers knife), which is attached to two pivot arms 15, 15 '. These pivoting arms are pivotally mounted on the tong frame 8 via a pivot axis 16. The pivot arms 15, 15 'are each connected to a strut 18, which in turn via an axis 20 on a driven Excenter 21 are stored. Seen in the material flow direction F of the fiber material W to be processed, a pair of tearing cylinders 24 is provided behind the tongs 1. The Abreisszylinderpaar 24 consists of a lower tear-off cylinder 24a, which cooperates with a tear-off pressure cylinder 24b to form a tear-off clamping line K. Schematically indicated is a fixed comb 11, which is fastened to the forceps frame 8 by means not shown and in which the tuft FB of the fiber material W (eg a cotton or fiber ribbons) is drawn in, if its end E in the direction of the clamping point K of the following Tear-off cylinder 24 is transported via the movement of the end E1 of an already present fiber fleece V. This is in the FIG. 1 indicated by dashed lines.

Within the pliers 1, a feed roller 27 is rotatably mounted, which is connected via a drive not shown in detail and performs a discontinuous rotational movement in order to transport the supplied cotton W in sections. The feed cylinder 27 has a shaft 28, via which it is rotatably mounted on both ends via bearings not shown in detail in bearing receptacles of the nipper frame. The drive of the feed roller 27 can be done via a known jack drive, which is controlled by the movement of the upper tong plate 14. However, it is also possible to make the drive of the feed roller 27 regardless of the movement of the upper tong plate, where he z. B. can be done via a cam, as for example in the GB-PS 933,946 is shown. It would also be conceivable to use the cam used in this embodiment directly on the circular comb shaft, as for example in the DE-PS 231 797 is shown. The drive of the feed roller 27 can be done in the forward or reverse of the pliers or pro rata in the forward and reverse. Subsequent to the feed roller, on the conveying path between the feed trough 26 and the nipper lip 30 of the lower tong plate, the fiber material is guided over a contact surface AF, on which, as in the following FIGS. 3 to 5 is still shown, the inventive attachment of a web 32 can take place. For this purpose, bores 52 (52 ') are provided in the area of the support surface AF, which are outside the conveying path of the fiber material W and are provided for receiving a web 32. As from the example of Figure 5 to remove these holes can be designed as blind holes 52 or as through-holes 52 '. Through-holes 52 'have the advantage that no dirt can accumulate in the region of the bore, if no web 32 is attached.

The combing takes place with the clamp 1 closed when it is in a rear position (not shown). In this case, the end of the fiber material projecting from the tongs (also called fiber tuft FB) reaches the area of the combing segment 7 of the circular comb 4 and is combed out.

After the combing process, the pliers are pivoted to a forwardmost position while being opened. The combed end of the fiber tuft FB is placed on the end of a previously partially transported back fiber web V and then transferred by the transport movement of the fiber web to the terminal point K of the tear-off cylinder 24. During the described sequence of movement, the tuft FB arrives in the area of the needles of a fixed comb 11. The rotational movement of the tears 24 causes the fibers of the tuft FB, which reach the nip K, to be pulled out of the tuft and soldered to the end of the fleece V. The nonwoven fabric is then combined via known devices to form a sliver and further transported.

In order for as few and uncontrolled floating fibers as possible to be able to participate during the tear-off process, it is necessary to keep the tear-off distance (distance between clamping point K of the tear-off cylinders and the clamping point in the feed trough 26 as small as possible.) The result is that the distance Ec (Ecartement) between The clamping point K and the nipper lip 30 should be kept as small as possible in their foremost position This can be achieved with the use of a guide element (web 32), as already described in US Pat EP-1 449 944 A1 has been described

In FIG. 2 a further known embodiment of a nipper unit 1 (pliers) of a combing head of a comber is shown, in contrast to the example of Fig.1 the tong frame 8a with the lower tong plate 12 fixedly mounted in the machine frame MS. The upper tong plate 14 is at two Swivel arms 15, 15 'attached, which are pivotally mounted about the axis 16 on the forceps frame. The pivotal movement of the upper pliers plate 14 is controlled by an arm 45, which is articulated via a pivot axis 46 on the respective pivot arm 15, and 15 a. On the opposite side, the respective arm 45 has a rotatably mounted roller 47 which rests on the outer circumference UF of a cam KS. The cam KS is rotatably mounted on the circular comb shaft 5 of a circular comb 4a. The rollers 47, one of which is provided at each end of the circular comb, are held in contact with the respective circumference UF of the cam KS via loading elements which act on the pivot arms 15, 15 '. As load elements for each of the pivot arms 15, 15 'in the present case bellows cylinder 40 are provided, which are in communication with a pressure source P, as shown schematically. The on the respective pivot arm 15, 15 'pivotally mounted bellows cylinder 40 may be secured to the opposite end on the machine frame or on a pivot frame, not shown. Such a device may, for. B. from the published WO 2010/012113 A1 be removed. In this publication, as in the present example, the Fig.2 to remove a circular comb 4a, wherein in addition to one, mounted on the circumference of the circular comb Kämmsegment 7 a tear-off segment 37 is fixed, which can form a nip line K1 with a sliding Abreiszylinder 22. The tear-off cylinder 22 is, as schematically indicated by a double arrow, rotatably mounted via an axis 23 which is slidably mounted in the direction of the circular comb axis 5.

Between the tear-off cylinder 22 and the tong lip 30 of the lower tong plate 12, a fixed comb 11 is attached.

In the in Fig.2 shown position, the pliers 1 is opened, wherein the pliers lip 31 of the upper pliers plate 14 is lifted from the pliers lip 30 of the lower pliers plate 12 and the end E of the pliers protruding, already combed fiber tuft FB in the nip K1 between the tear segment 37 and which is held the tear-off cylinder 22. The tear-off cylinder 22 is pressed against the peripheral surface of the tear-off segment 37 via loading means, not shown, and rotated by friction by the movement of the tear-off segment. There during this tearing off the supply via the feed roller 27 of further fiber material W (cotton web or slivers) is prevented, via the nip K1 a so-called fiber package from the end of the presented fiber material W deducted. Ie. All fibers, which are not retained by the nip in the area between the feed roller 27 and its associated feed trough 26 are withdrawn via the nip K1. In this tearing off the fiber material is pulled through the clothing of the Fixkammes 11. On the way between the feed roller 27 and the nipper lip 30 of the lower nipper plate 12 is the fiber material W (also as in the example of the Fig.1 ) guided over a bearing surface AF, in which at both ends, which are outside the conveying path of the fiber material, bores (recesses) 52 (52 ') are provided which serve to receive a web 32, which is still in the following FIGS. 3 to 5 will be described in detail.

The fiber package drawn off from the end of the fiber material is transferred in the direction of a following, rotatably mounted screening drum 42, to which a negative pressure from a vacuum source U is applied in the interior via the line L. In order to specify the air circulation in the area of the screen drum, a cover element 43 is provided inside the screen drum. During the soldering process under the action of the generated negative pressure, the end of the withdrawn fiber bundle is placed on the end of the webbed on the nonwoven fabric V and brought into an overlap with this. The nonwoven fabric formed in this way passes through the rotational movement of the screen drum indicated by arrow into the area of a take-off roll W. From there, the fiber web V is detached from the screen drum and fed to a fleece stacker VT, at which the fleece is combined to form a fiber band. This sliver is delivered via a subsequent Kalanderwalzenpaar KW on a conveyor table T, on which it is fed with other slivers of adjacent, not shown combing a subsequent drafting system (not shown).

Fig. 3 shows an enlarged partial section of the forceps 1 (after Fig.1 or Fig.2 ) in the closed position in the front region of the pliers lip 30 of the lower Pliers plate 12. Below the feed cylinder 27, the pliers plate 12 on a feed trough 26 which cooperates with the feed cylinder to transport the, supplied by a template (cotton wool, cans) fiber material W in the direction of the front pliers lip 30.

This promotion of the fiber material via a discontinuous drive not shown in detail of the feed roller.

Directly after the feed trough 26, a web 32 provided with a trapezoidal cross-section is mounted on the lower tong plate 12, which extends across the width B of the fiber material W transversely to the material flow direction F. The web 32, which has a height H, is provided with a guide surface 35, via which the fiber material W, which is discharged from the feed trough 26 through the feed roller 27, is subsequently passed into the clamping region of the tongs lip 30. For lateral guidance of the fiber material W 32 side guides SF1 and SF2 are mounted above the guide surface 35 at both ends of the web, as in particular from Figure 5 (View X the Figure 3 ) can be seen.

In the closed position of the forceps 1, such as. In Figure 3 is shown, the forceps lip 30 of the lower forceps plate 12 with the forceps lip 31 of the upper forceps plate 14 (also called pliers knife) two clamping points KU and KO for the fiber material. However, it is also possible to provide only one nip. The fiber tuft FB protruding from the lower clamping point KU enters the area of action of a toothed set G of a combing segment 7 and is combed out. Ie. all components, in particular the short fibers, which are not clamped by the clamping point KU, are combed out of the tuft FB by the combing segment and fed downwards to a suction channel, not shown. The dimension a, with which the tuft FB protrudes from the lower clamping point KU of the tongs 1, is decisive for the percentage of combing out. Ie. the larger the dimension a, the more fibers are no longer clamped by the nip KU and are thus combed out by the combing segment. The combing becomes smaller when the dimension a is smaller. The dimension a and thus the degree of combing can be determined by the selection of the height H of the web 32, with Ecartement Ec remaining the same. The Ecartement Ec is the distance between the smallest distance between the nipper lip 30 of lower pliers plate 12 and the subsequent tear-off line K, or K1. Provided a reciprocating pliers accordingly Fig.1 The Ecartement Ec can be influenced by changing the pivoting movement of the pliers. In the embodiment of Fig. 2 the Ecartement between the forceps lip 30 and the tear-off clamping line K1 is substantially constant and can only be changed by moving the tear-off cylinder.

By simply replacing the web 32, the degree of combing can be changed.

Above the guide surface 35 of the web 32 at a distance two guides SF1 and SF2 are mounted, which lead the fiber material W in its width B laterally with their opposing arcuately shaped guide surfaces FF. The attachment of the side guides SF1, SF2 is from the Figure 4 and Figure 5 seen. The web is provided in the region of its two ends, each with a bore 53 in which a pin 54 is attached. The attachment can be done by pressing or by gluing. The pin 54 (with, for example, a circular cross-section) projects beyond the guide surface 35 of the web 32 with a smaller-diameter attachment 55. The attachment 55 protrudes into a depression 58 of the respective guide SF1 or SF2. The attachment 55 is firmly connected to the respective guide SF1, SF2 by pressing or gluing. Of course, there are also other types of attachment conceivable. Starting from the lower surface SU of the web 32, with which it rests in the installed state on the support surface AF of the lower tong plate 12, the pin 54 projects beyond the surface b the surface SU. With this, the lower surface SU superior part of the pin 54, a positive connection with a recess 52 is made when installing the web, which is mounted in the lower tong plate 12. The cross-sectional shape of the pin 54 and the recess 52 are designed and dimensioned to each other to ensure a tight fit. In the present example, the pin is provided with a circular cross-section. In this case, the recess is designed as a blind hole 52 or as a through hole 52 '. However, the dimensioning of the recess 52 and the pin 54 is set so that a manual disassembly and assembly in this area is possible. If necessary, the pin 54 can still be provided with a chamfer 54 '(FIG. Figure 5 ) in order to facilitate insertion of the pin in to allow the recess 52 (52 '). When using a blind hole 52, the end of the protruding into the blind hole pin 54 still has a small distance to the end of the blind hole 52, when the web 32 with the lower web surface SU completely on the support surface AF of the lower tong plate 12 rests. This is schematically in the embodiment of Figure 5 shown. This ensures complete installation of the bar on the tong plate.

Between the guides SF1, SF2 magnets 50 in the region of the lower surface SU of the web 32 in recesses 49 are mounted at a distance m. This is especially true of the 5 b can be seen, wherein the magnets 50 z. B. are designed in the form of a circular disc. In this case, the lower surface of the magnets 50 is exactly on the level of the lower surface SU of the web 32 or is offset to a slight extent between 0.05 and 0.5 mm inwards.

About these magnets 50, which are pressed or glued into the recesses 49, is held by the magnetic force of the web with its lower surface SU on the support surface AF of the lower tong plate safely and accurately in abutment.

It is also a solution conceivable to manufacture the bridge of an injection molded part, wherein in the manufacture of the magnets are cast directly with and integrated.

Like from the Fig.3 and Fig.4 to further remove, the guides SF1, SF2 have a corresponding arcuate side surface 55 in the installed state of the web 32 and the feed roller 27 a small distance d between 0.1 and 2.5 mm to the peripheral surface US of the feed roller 27 has.

With this massive design, or assignment, it is to be prevented that the web 32 can unintentionally detach from its installed position and reach the area of other elements of the comber (eg in the region of the combing segment 7 of the circular comb 4). Under certain circumstances, this would lead to major damage to the comber and lead to longer downtimes. However, this is prevented by the proposed embodiment. Like from the Fig. 4 to take the web 32 can move maximally in the position, which is shown by dashed lines. In this position, the side surface 56 comes to stop against the peripheral surface US of the feed roller 27, which a further movement of the web 32 is blocked or blocked. The pin 54 protrudes in this position with a measure c in the recess 52 of the lower tong plate 12, whereby a horizontal displacement of the web is suppressed on the plane of the support surface. As a result, the disassembly of the web 32 can not take place until the feed roller has been dismantled or removed.

In the example of Fig. 5a a further embodiment is shown, wherein for securing the web 32 on the lower tong plate 12 of the web 32 in the region of its two ends (only one end shown), each with a continuous bore 65 is provided. On the lower pliers plate in a recess 63 (bore) each a bolt 60 is fixed, which faces the respective bore 65 prior to assembly of the web 32. To simplify the assembly, the bolts 60 are provided with a chamfer 61. Likewise in the example of the Fig.5 and Fig.5b Magnets 50 mounted at a distance m. The respective side guide (only one shown) is offset to the bore 65 via a screw 70 on the guide surface 35 of the web 32 attached. The screw protrudes through a stepped bore 69 of the web 32 and is screwed into a threaded hole 67 of the respective guide SF1, SF2. An advantage of this design is the better view during the assembly process in the form of positive connection between the bolt 60 and the holes 65. That is, through the upwardly open holes 65, it can be better recognized whether the holes 65 and the bolt 60 at Mounting process coaxially facing. The side guides SF1, SF2 otherwise have the same shape as in the embodiments of Figure 4 and Figure 5 , With the embodiment of the web proposed according to the invention, it is now possible, if required, to exchange the webs on the respective combing head of the comber easily and quickly without a special tool. By the proposed magnets ensures that the web 32 rests safely and completely on the support surface AF of the lower tong plate 12 over its entire length even at high dynamic loads by a high Kammspielzahl.

Claims (11)

1. Nipper unit (1) of a combing machine, with a lower nipper plate (12), which, with an upper nipper plate (14) that is moveably mounted in the nipper unit, can form, in the region of its nipper lip (3) a clamping point (KO, KU) and a feed roller (27) rotatable mounted above the lower nipper plate (12) inside the combing unit (1), wherein inserted after the combing unit 91), there is at least one detaching roller (24a, 24b, 22) mounted in the machine frame (MS) for forming a detaching clamp line (K, K1) and with a bridge (32) removable attached between the feed roller (27) and the nipper lip (30) on the lower nipper plate (12) and oriented transversely to the conveying direction (F) of the fiber mass (W), wherein below the lower nipper plate (12) there is arranged a rotatable mounted circular comb (4, 4a) for combing out fiber tufts (FB), characterized In that the bridge (32) in the region of its contact surface (SU), which is opposite a contact surface (AF) of the lower nipper plate (12) consisting at least partially of ferromagnetic material, has magnetic means (5) and means (54, 60) are provided in the region of both ends of the bridge (32) by which the bridge is fixed in a form-fitting manner in the plane of the contact surface (AF) on the lower nipper plate (12).
2. Nipper unit (1) according to claim 1, characterized In that the magnetic means-seen in the longitudinal direction of the bridge (32) - consists of multiple magnets (50) arranged at an interval (m) to each other on the bridge.
3. Nipper unit (1) according to claim 2, characterized in that the magnets (50) are attached in recesses (49) of the bridge (32).
4. Nipper unit (1) according to one of the claims 1 to 3, characterized in that the bridge (32) has elevations (54) in the region of both of its ends, that point in the direction of the contact surface (AF) of the lower nipper plate (12) and project into cavities (52, 52') of the lower nipper plate (12) and form with these a form-fitting connection.
5. Nipper unit (1) according to one of the claims 1 to 3, characterized in that the contact surface (AF) of the lower nipper plate (12) has elevations (60), which project into recesses (65) of the bridge (32) in the region of both of its ends and form with these a form-fitting connection.
6. Nipper unit (1) according to one of the claims 1 to 5, characterized in that the bridge (32), in the region of both of its ends, is equipped with lateral guides (SF1, SF2) extending upward from its guide surface (35), for the fiber material (W).
7. Nipper unit (1) according to claims 6 and 4, characterized in that the respective lateral guide (SF1, SF2) is connected to the respective elevation (54, 55) and the bridge (32) has in this region an opening (53) through which at least a portion of the respective elevation (54) and / or the respective lateral guide (SF1, SF2) projects into.
8. Nipper unit (1) according to one of the claims 1 to 7, characterized in that the feed roller (27) in its installed state prevents the removal of the bridge (32) from its form-fitting connection with the lower nipper plate (12).
9. Nipper unit (1) according to claims 8 and 6, characterized in that the lateral guides (SF1, SF2) on the side opposite the feed roller (27), are each equipped with an arc-shaped surface (56), which in the installed state have a clearance of between 0.1 and 2.5 mm to the circumferential surface (US) of the feed roller (27).
10. Nipper unit (1) according to one of the preceding claims, characterized in that the bridge (32) has a trapeze-shaped cross-section.
11. Bridge (32) for fixing on a contact surface (AF) of a lower nipper plate (12) of a nipper unit (1), characterized by a contact surface (SU) consisting at least ferromagnetic means (50) and with means (54, 60) in the region of both ends of the bridge provided for fixing the bridge in a form-fitting manner in the plane of its contact surface (AF) of the opposite lower nipper plate (12), which consists at least partially of ferromagnetic material.

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