Abstract:
In a card flat bar having a card flat clothing, the card flat clothing is magnetically attached to the card flat bar body and, in use, lies opposite a clothed roller. In order to hold the clothing element against the card flat bar in a structurally simple way in the event of an increase in force on the clothing, especially to prevent the card flat clothing from making contact with the cylinder clothing, and to allow quick replacement of the card flat clothing strip, on the fibre material inlet side of the card flat clothing—seen in the direction of rotation of the roller—there is associated with the card flat bar a counter-bearing, stop or the like with which a base of the clothing co-operates in the direction towards the cylinder.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The present application claims priority from German Patent Application No. 10 2009 013 412.3 dated Mar. 18, 2009, the entire disclosure of which is incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     The invention relates to an apparatus on a carding machine for cotton, synthetic fibres and the like, in which there is at least one card flat bar having a card flat clothing. 
     It is known in a card flat bar for the card flat clothing, preferably wire hooks, to be arranged in a strip-like support layer, the clothing being attached to the card flat bar and lying opposite the clothing of a roller, for example the cylinder, and at least the regions of the card flat clothing that face the card flat bar comprising an iron material, especially of steel, with at least one magnetic means (element) being provided between the card flat bar and the regions of the card flat clothing that face the card flat bar. 
     The revolving card top of a carding machine is the crucial technological element for reducing the number of neps in the fibre material, for example, cotton, in its most highly opened state. In its interaction with the cylinder, the revolving card top loosens the fibre knots, it being necessary for the spacing to be as small as possible but for mutual contact between the clothings to be prevented. Contact results in unnecessary wear. Premature wear in turn results in a reduction in quality. The flexible revolving card top is also the only element which can be set to extremely narrow carding nips without significant adverse technological secondary effects. 
     In order reliably to manage extremely narrow carding nips, precision components are a prerequisite. The revolving card flats used simultaneously on a machine are referred to as a card flat set. The differences in dimensions from card flat to card flat in the card flat set should be as small as possible. Likewise, each individual card flat should have a high degree of evenness across the width of the machine. Because increased precision is always associated with increased cost, it is necessary to combine increased precision with optimum handling at an acceptable cost. In practice, the clothings are clipped onto the card flats using enormous forces. The clipping-on operation, which has to be made reversible for re-clothing, has an adverse effect on precision and is not possible without destruction of the clothing. 
     In a known apparatus (DE 10 2006 005 605 A), the card flat clothing is adhesively bonded, in a tolerance compensating manner, to a metal backing sheet and is held in the revolving card top by a planar magnetic strip. The magnetic strip itself is in turn adhesively bonded, in a tolerance compensating manner, to the card flat bar. The magnetic force absorbs the process forces during the carding process with a high degree of reliability. As a result, many of the disadvantages of the old clip-on card flat system have been eliminated. The card flat sets have a high degree of precision even without an additional grinding process. Handling during re-clothing is optimum, because the clothing can be demounted, without being destroyed, using a single movement. The new clothing can be inserted again just as quickly. 
     The magnetic connection is a force-based connection. If a threshold force opposite to the attractive force of the magnet is applied, the clothing strip becomes detached from the card flat bar. The threshold force is such that the normal process forces can be transmitted with a high degree of reliability. This has been demonstrated by a large number of practical tests and experiments. The “old” mounting technique using clips was an interlocking connection. That connection could be broken only by overcoming the rigidity of the component. The forces necessary for that purpose are in turn a multiple greater than the threshold force of the “new” magnetic connection. 
     If operating conditions that can be considered abnormal then arise in a carding machine, forces can develop which exceed the threshold force of the magnet but still lie significantly below the connection strength of the clip-on technique. Abnormal operating conditions arise when the nips used are too narrow; when the fibre/clothing combination has been incorrectly selected and therefore cylinders become clogged; when, as a result of fibres that are difficult to process, temperatures suddenly rise very rapidly and there is substantial contact between clothings; when operators do not recognise the abnormal operating conditions in good time and allow the machines to continue running, and so on. It can also happen that an unusually large or solid disruptive element, for example a trash particle, fibre knot or the like, projects at least partly beyond the circle of tips of the cylinder and thus exerts undesirable pressure on the forwardly arranged regions (front regions) of the clothing of at least one card flat bar. In summary, there are situations which occur extremely rarely (exceptional cases) but give rise to enormous adverse forces. 
     In normal operation, the magnet absorbs all the operating forces and provides for precision support. In an abnormal operating state, the interlocking connection safeguards against contact with the cylinder clothing. 
     SUMMARY OF THE INVENTION 
     It is an aim of the invention to create an apparatus which, in particular, provides a structurally simple way of holding the clothing element against the card flat bar in the event of an increase in pressure on the card flat clothing, especially of preventing the card flat clothing from making contact with the cylinder clothing, and allows quick replacement of the card flat clothing strip. 
     The invention provides a card flat bar for use in a carding machine opposite a clothed roller of said machine, having a card flat bar body having a material inlet side at which in use fibre material is received, and a card flat clothing strip which is magnetically attachable to the card flat bar body, wherein the card flat bar body includes a counter-bearing associated with said material inlet side and the card flat clothing strip comprises a counter-element arranged to co-operate, in use, with the counter-bearing in a direction towards said opposed clothed roller. 
     Because there is associated with the card flat bar, on the fibre material inlet side of the card flat clothing, a counter-bearing, stop or the like with which the base and/or the support member co-operate(s) in the direction towards the roller, for example carding cylinder, undesirable forces are compensated for. In this structurally simple way, in the event of an increase in pressure on the clothing, the clothing element is held against the card flat bar, that is to say contact between the card flat clothing and the cylinder clothing is reliably avoided even if there is local detachment from the magnet. The invention has the further substantial advantage that in the event of replacement the card flat clothing strip can be removed or inserted without problems, because there is no counter-bearing, stop or the like on the fibre material outlet side of the card flat clothing. 
     Advantageously, the clothing strip has a support layer and a base for attachment to the card flat bar, and the counter-element is the base. The counter-element may be, for example, a shoulder or the like on the base. In another embodiment, the counter-element may be the support layer. For example, the counter-element may be a shoulder or the like on the support layer. In certain embodiments the base or the support layer co-operates with the card flat bar by means of an interlocking connection. The counter-bearing may be in any suitable form. Illustrative arrangements for the counter-bearing include those in which the counter-bearing is a shaped portion of the foot of the card flat bar body, for example, an angled edge on the card flat foot, an undercut, a nose, an angled side on the card flat foot, or a groove in the card flat foot; and arrangements in which a bearing element is inserted into or attached to the foot of the card flat body, for example, a bent-over sheet metal element or the like, a screw, a bolt or the like, a resilient element, or a clip-like element. In the case of a groove, the base of the clothing , advantageously projects into the groove. Advantageously, the base projects beyond the support layer of the clothing. The counter-bearing may extend under the base or the support layer of the clothing at a spacing of about from 1 to 3 mm. Advantageously, the counter-bearing, for example the stop, is present at least partially along the longitudinal edge of the card flat foot on the fibre material inlet side. Advantageously, there is a spacing (play) between the upper side of the counter-bearing and the underside of the base or support layer. Advantageously, during normal carding conditions, the spacing (play) is smaller than the spacing between the card flat clothing and the clothing of the cylinder (carding nip). 
     In some embodiments, there is a counter-bearing in the region of each of the two end faces of the card flat foot (card flat heads). Advantageously, when the threshold force of the magnet is exceeded the clothing strip is supported on the counter-bearing. That prevents the clothing strip from contacting the opposed roller. For example, the base may be supported on the counter-bearing in the event of abnormal carding conditions resulting in detachment of the clothing strip. Where the counter-element is the support layer, the support layer may be supported on the counter-bearing in the event of detachment of the carding strip. 
     In some embodiments, magnetic means are attached to the card flat bar, for example, by means of an adhesive layer or the like, or by means of a screw connection or the like. In some embodiments, the magnetic means consists of a permanently magnetic material. It will be appreciated that, under normal carding conditions, the magnetic force is greater than other forces acting on the clothing, for example carding force, force of a rotating cleaning roller or the like. Preferably, the clothing is removable from the magnetic means. Preferably, the clothing is joined to the card flat bar by means of the magnetic means as attachment element. Preferably, the clothing is removably detachable from the magnetic means. In one preferred embodiment, the clothing, which is inserted into a substrate, for example fabric or the like, consists of wires or the like which are bent into approximately a U-shape and inserted in such a way that the crosspiece of the U-shaped wires or the like runs on the rear side of the substrate. Preferably, between the card flat bar and the card flat clothing there is a compensating layer which is able to compensate for the different spacings between the card flat bar and the card flat clothing. In certain embodiments, an adhesive layer is provided. The clothing is preferably a clothing strip. In certain embodiments, the card flat bar comprises a neodymium magnet. In certain advantageous forms of clothing, a thin metal support is advantageously provided. Advantageously, the clothing is a flexible clothing. Preferably, the flexible clothing comprises a support and clothing tips, wires, hooks or the like. Preferably, the support is strip-shaped. In other embodiments, the clothing consists of sawtooth wire strips, for example all-steel clothing. 
     Advantageously, the clothing is attached to the card flat bar in the region of the foot surface. Advantageously, a plastics material, a synthetic resin, for example epoxy resin, or the like, is provided as compensating composition. Preferably, the card flat bar is an extruded profile made from a lightweight metal, for example aluminium. Preferably, the extruded profile is a hollow profile. Preferably, the card flat bar comprises a supporting member, with which are associated two end head parts (card flat heads). Preferably, the end head parts are pins made of hardened steel or the like. Preferably, a supporting element of the clothing (for example, of textile material) and the compensating layer are arranged in a recess in the foot face (supporting member). Preferably, the recess is defined by at least two lateral ribs or the like on the longitudinal sides of the supporting member of the card flat bar. In some embodiments, the underside of the clothing strip against which the backs of bent wires of the clothing are located is held by means of a magnet fixed to the card flat bar. In certain embodiments, a clothing strip is included, to which there is additionally attached, by way of a compensating adhesive layer, a metal sheet which is brought into connection with the magnet of the card flat bar. In preferred embodiments of the invention, a vertical linkage on the fibre material inlet side is supported mechanically. 
     Advantageously, the magnetic means comprises an elongate magnetic element, for example magnetic tape, magnetic strip, magnetic bar or the like, that runs in the longitudinal direction of the card flat bar. In some embodiments, a plurality of magnetic elements are present in the longitudinal direction of the card flat bar. Preferably, the magnetic elements are arranged spaced apart from one another. In certain embodiments, the magnetic structural elements are arranged offset with respect to one another. Preferably, the offset runs in the working direction. In certain embodiments, a base made of a magnetic material is arranged on the rear side of the card flat clothing. Advantageously, the base is a steel tape, metal sheet or the like. Advantageously, the base has, on the fibre material inlet side, shoulders, ribs or the like which are bent at an angle at the side. 
     In some embodiments, the card flat clothing has at least two clothing groups which are each held by a magnet. For example, there may be at least two clothing groups each having a heel zone opposite the roller clothing. In certain embodiments the card flat clothing consists of a multiplicity of all-steel clothing wires which are arranged in the axial direction with respect to the clothed roller, for example the cylinder. Preferably, the card flat clothing is held against the card flat bar by at least, one magnetic element. 
     In certain preferred embodiments, magnetic means is integrated into the card flat bar. Advantageously, a base made of a fine material is provided on the rear side of the card flat clothing. In one advantageous embodiment, magnetic means is formed with the card flat bar by casting. In another advantageous embodiment, the magnetic means is incorporated into the card flat bar by casting or compression moulding. Advantageously, the magnetic means is simultaneously incorporated during the manufacture of the card flat bar. In one advantageous embodiment, at least one and preferably each of the marginal regions bordering the longitudinal edges is provided with tips. Advantageously, the magnetic element is at least partly in contact with the sheet-form metal support of the clothing. 
     The invention also provides a card flat bar for a carding machine for cotton, synthetic fibres and the like, having a card flat clothing, wherein the card flat clothing, preferably wire hooks, which is arranged in a strip-shaped support layer, is attached to the card flat bar and at least the regions of the card flat clothing that face the card flat bar consist of an iron material, especially of steel, with at least one magnetic means being provided between the card flat bar and the regions of the card flat clothing that face the card flat bar, wherein on the fibre material inlet side of the card flat clothing—seen in the direction of rotation of the cylinder—there is associated with the card flat bar a counter-bearing, stop or the like with which the base co-operates in the direction towards the cylinder. 
     Further, the invention provides a flexible clothing for a card flat bar on a carding machine for cotton, synthetic fibres and the like, having a card flat clothing, wherein the card flat clothing, preferably wire hooks, which is arranged in a strip-shaped support layer, is attachable to the card flat bar and at least the regions of the card flat clothing that are arranged to face the card flat bar consist of an iron material, especially of steel, wherein on the fibre material inlet side of the card flat clothing—seen in the direction of rotation of the cylinder—there is associated with the card flat bar a counter-bearing, stop or the like with which the base co-operates in the direction towards the cylinder. 
     Moreover, the invention provides a carding machine having a revolving card flat assembly for cotton, synthetic fibres and the like, in which there is at least one card flat bar having a card flat clothing, wherein the card flat clothing, preferably wire hooks, which is arranged in a strip-shaped support layer, is attached to the card flat bar and lies opposite the clothing of a roller, for example the cylinder, and at least the regions of the card flat clothing that face the card flat bar are provided with at least one magnetic element wherein on the fibre material inlet side of the card flat clothing—seen in the direction of rotation of the cylinder—there is associated with the card flat bar a counter-bearing, stop or the like with which the base co-operates in the direction towards the cylinder. 
     The invention also provides an apparatus on a carding machine for cotton, synthetic fibres and the like, in which there is at least one card flat bar having a card flat clothing, wherein the card flat clothing, preferably wire hooks, which is arranged in a strip-like support layer, is attached to the card flat bar and lies opposite the clothing of a roller; for example the cylinder, and at least the regions of the card flat clothing that face the card flat bar consist of an iron material, especially of steel, with at least one magnetic means (element) being provided between the card flat bar and the regions of the card flat clothing that face the card flat bar, wherein on the fibre material inlet side of the card flat clothing—seen in the direction of rotation of the cylinder—there is associated with the card flat bar a counter-bearing, stop or the like with which a counter-element associated with the card flat clothing co-operates in the direction towards the cylinder. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagrammatic side view of a carding machine having a revolving card top with card flat bars according to a first embodiment of the invention; 
         FIG. 2  shows card flat bars of the revolving card top and a portion of a slideway, of a setting bend (flexible bend) having a side screen and of the cylinder, as well as showing the carding nip between the clothings of the card flat bars and the cylinder clothing; 
         FIG. 3   a  is a side view in section through a portion of a card flat bar with a counter-bearing and with magnetic strip and clothing strip (wire hook clothing) in the assembled position; 
         FIG. 3   b  shows the card flat bar with counter-bearing and magnetic strip in accordance with  FIG. 3   a , but with a separately detached clothing strip; 
         FIG. 4  is a side view in section of a further card flat bar according to the invention, showing diagrammatically the installation of the clothing strip in the card flat foot of the card flat bar or the demounting of the clothing strip therefrom; 
         FIG. 5  shows the force application point and the angle of application with respect to the card flat clothing on the fibre material inlet side; 
         FIG. 6   a  shows on the fibre material inlet side of a card flat bar according to  FIG. 4 , a spacing between the underside of a shoulder of the base and the counter-bearing; 
         FIG. 6   b  shows the card flat bar according to  FIG. 4  with a spacing between the upper side of the base and the magnet 
         FIG. 7  shows an embodiment having an angled side on the counter-bearing and on the base; 
         FIG. 8  shows an embodiment having a screw as counter-bearing; 
         FIG. 9  shows an embodiment having a flexible metal sheet as counter-bearing; 
         FIG. 10  shows an embodiment having a counter-bearing with which the support layer of the clothing strip co-operates, and 
         FIG. 11  shows an embodiment having a shoulder on the supporting element which co-operates with the counter-bearing. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     With reference to  FIG. 1 , a carding machine, for example a flat card TC 07 (trademark) made by Trützschler GmbH &amp; Co. KG of Mönchengladbach, Germany, has a feed roller  1 , feed table  2 , lickers-in  3   a,    3   b,    3   c,  cylinder  4 , doffer  5 , stripper roller  6 , nip rollers  7 ,  8 , web guide element  9 , web funnel  10 , delivery rollers  11 ,  12 , revolving card top  13  with card top guide rollers  13   a,    13   b  and card flat bars  14 , can  15  and coiler  16 . The directions of rotation of the rollers are indicated by curved arrows. Reference letter M denotes the centre point (axis) of the cylinder  4 . Reference numeral  4   a  denotes the clothing and reference numeral  4   b  denotes the direction of rotation of the cylinder  4 . Reference letter B denotes the direction of rotation of the revolving card top  13  in the carding position and reference letter C denotes the return transport direction of the card flat bars  14 , with reference numerals  30 ′,  30 ″ denoting functional elements and reference numerals  13   a  and  13   b  denoting card top guide rollers. The arrow A denotes the working direction. 
     In accordance with  FIG. 2 , on each side of the carding machine there is provided a setting bend  17  (flexible bend) which is integrated integrally into the associated side screen  19 . The setting bend  17  has a convex outer surface  17   a  and an underside  17   b.  On top of the setting bend  17  there is a slideway  20 , for example made of low-friction plastics material, which has a convex outer surface  20   a  and a concave inner surface  20   b.  The concave inner surface  20   b  rests on top of the convex outer surface  17   a  and is able to slide thereon in the direction of arrows D, E. Each card flat bar  14  consists of a rear part  14   a  and a card flat foot  14   b.  Each card flat bar  14  has, at each of its two ends, a card flat head, each of which comprises two steel pins  14   1 ,  14   2 . Those portions of the steel pins  14   1 ,  14   2  that extend out beyond the end faces of the card flat foot  14   b  slide on the convex outer surface  20   a  of the slideway  20  in the direction of the arrow B. A clothing  18  is attached to the underside of the card flat foot  14   b.  Reference numeral  21  denotes the circle of tips of the card flat clothings  18 . The cylinder  4  has on its circumference a cylinder clothing  4   a,  for example a sawtooth clothing. The tooth height of the sawteeth is, for example, h=2 mm. Reference numeral  22  denotes the circle of the tips of the cylinder clothing  4   a.  The spacing (carding nip) between the circle of tips  21  and the circle of tips  22  is denoted by reference letter a and is, for example, 3/1000″. The spacing between the convex outer surface  20   a  and the circle of tips  22  is denoted by reference letter b. The spacing between the convex outer surface  20   a  and the circle of tips  21  is denoted by reference letter c. The radius of the convex outer. surface  20   a  is denoted by reference letter r 3  and the radius of the circle of tips  22  is denoted by reference letter r 1 . The radii r 1  and r 3  intersect at the centre point M of the cylinder  4 . Reference numeral  19  denotes the side screen. The card flat bars  14  are extruded hollow profiles made of aluminium having an internal cavity  14   c.    
       FIGS. 3   a  and  3   b  show a first embodiment of card flat bar according to the invention. The card flat clothing  24  consists of clothing tips  18  (wire hooks) and a supporting element  25  (support layer) made of a textile material. The wire hooks  18  are approximately U-shaped and, punched through the surface  25 ′, are fixed in the supporting element  25 . The turn regions  18 ′ (see  FIG. 4 ) of the wire hooks  18  project beyond the surface  25 ′. The ends of the wire hooks  18 , the clothing tips, are free. The wire hooks  18  consist of steel wire. 
     Two ribs  14   d,    14   e  are provided laterally on the card flat foot  14   a  in the longitudinal direction, so that in the region of the foot face there is a recess  14   f,  by means of which the card flat clothing  24  is held, protected and embedded. In the recess  14   f  there is arranged a magnetic element  29 , for example a magnetic tape, magnetic strip, magnetic bar or the like, which is attached to the foot face by means of an adhesive layer  30 . The magnetic element can also be formed on the card flat bar by casting, compression moulding or the like, for example magnetic powder with a curable resin. The magnetic element is advantageously a permanent magnet, for example a neodymium magnet. In the lower recess  14   f  there is arranged the card flat clothing  24 . The card flat clothing  24  is attached to, i.e. held against, the magnetic element  29  by its region remote from the free clothing tips  18  (teeth). 
     In the arrangement shown in  FIGS. 3   a  and  3   b , the card flat clothing  24  (clothing strip) consists of wire hooks  18  and supporting element  25 . The arrangement additionally has a compensating layer  32  which enables card flat precision to be improved and the attachment surface area to be enlarged. The compensating layer  32  is advantageously an adhesive layer to which there is attached a metal sheet  33  (base) or the like, for example a steel sheet, which is in contact with the magnet  29 . 
       FIG. 3   a  shows the card flat bar  14  and the card flat clothing  24  in the assembled state, the card flat clothing  24  being held so securely by the magnet  29  by way of the steel sheet  33  that, during operation, forces acting through the carding machine on the card flat clothing  24  hold the card flat clothing  24  against the magnet  29 . According to  FIG. 3   b , the card flat clothing  24  has, for example in the event of wear, damage or the like to the clothing hooks  18  including the base  33 , been separated from the magnet  29  and removed from the recess  14   f.  Separation from the magnet  29  can be effected by means of a suitable tool with which the holding force of the magnet is overcome. The separation can be effected manually even while the carding machine is running, during operation, on the return transport of the card flat bars  14  (see arrow C in  FIG. 1 ). The card flat bars  14  are removable from the toothed drive belt (not shown). 
     In the card flat bar of  FIG. 3   a ,  3   b , on the fibre material inlet side ES of the clothing  18 —seen in the direction of rotation  4   a  of the cylinder  4  (see FIG.  1 )—a counter-bearing  34  is present only on the rib  14   d.  The counter-bearing  34 , which projects into the recess  14   f  in the form of a shoulder on the rib  14   d,  is formed in one piece with the rib  14   d  during the extrusion of the card flat bar  14 . In this arrangement, rib  14   d  and counter-bearing  34  are merged integrally in one piece. The width of the rib  14   d  is denoted by reference letter d. According to  FIG. 3   b , the counter-bearing  34  has a width e and a height f. The width e is about from 1 to 3 mm and projects beyond the width d. The length l (not shown) of the counter-bearing  34  corresponds to the working width of the card flat bar  14  across the cylinder  4  and can be, for example, 1000 mm, 1200 mm or 1500 mm or more. The counter-bearing  34  can be of one-part or multi-part construction in the longitudinal direction. 
     In the embodiment of  FIG. 3   b , the supporting element  25  has a width g. The width of the adhesive layer  32  corresponds to the width g of the supporting element  25 . The width h of the sheet metal strip  33  is greater than the width g of the supporting element  25 . In that way, the edge region  33 ′ of the sheet metal strip  33  on the fibre material inlet side ES of the clothing  18  projects beyond the supporting element  25  by amount i. As shown in  FIG.3   a , reference letter k denotes the width of the magnetic element  29 . 
       FIG. 4  shows diagrammatically the installation of the clothing strip  24  in the card flat foot  14   b  of the card flat bar  14  and the demounting of the clothing strip therefrom. Because the rib  14   e  is not associated with a counter-bearing, stop or the like, the clothing strip  24 , for example having a worn or damaged clothing  18 , can —after separation of the sheet metal strip  33  from the magnetic element  29 —be rotated clockwise in the direction of arrow F out of the recess  14   f.  The edge region  33 ′ of the sheet metal strip  33  that projects by amount i (see  FIG. 3   b ) is rotated about the upper edge region of the counter-bearing  34  in direction F, the edge region  33 ′ at the same time being withdrawn from a groove  35  in the rib  14   d,  which groove runs in the longitudinal direction l of the card flat bar  14 . A new clothing strip  24  is installed in the card flat foot  14   b  of the card flat bar  14  in a corresponding way. First the edge region  33 ′ is introduced, around the upper edge region of the counter-bearing  34 , into the groove  35 , so that the clothing strip  24  is rotated anti-clockwise in the direction of arrow G until the sheet metal strip  33  adheres firmly to the magnetic element  29 . In that way, handling during installation and demounting of the clothing strip is problem-free. 
     By way of illustration with reference to a card top bar according to  FIG. 4 ,  FIG. 5  shows, by the force application point  36  and the angle of application a on the fibre material inlet side ES. Reference letters AS denote the fibre material outlet side. The force that arises in any particular case can vary greatly in magnitude but the force application point  36  and the application angle a is limited. It is therefore possible to create geometric conditions which absorb the forces through an interlocking connection.  FIG. 5  shows an exemplary configuration of such an interlocking connection. It will be apparent from, for example, the illustrative embodiment of  FIGS. 4 and 5  that the counter-bearing provided, in accordance with the invention, presents on obstacle to removal of the clothing strip in the direction towards the roller, during use, at the position most prone to abnormal carding conditions, that is at the material inlet side of the card flat. On the other hand, the counter-bearing does not impede removal of the strip when desired (see, for example,  FIG. 4 ). 
     Reference letter  4   b  denotes the direction of rotation of the cylinder (flow of fibre material). The angle of application a represents a possible variation of the direction of application of the threshold force. The curved arrow I indicates the direction in which in an abnormal operating state, that is to say in the event of the limit force being exceeded, the clothing strip  24  is rotated minimally about a pivot point in the region of the rib  14   e  (see  FIG. 6   b ). 
     In accordance with  FIG. 6   a , on the fibre material inlet side ES there is a spacing m between the underside of the sheet metal strip  33  serving as base and the upper side  34 ′ of the counter-bearing,  34 .  FIG. 6   a  represents the normal operating state. According to FIG.  6   b , on the fibre material inlet side ES there is a spacing n between the upper side  33 ′ (see  FIG. 3   b ) of the sheet metal strip  33  serving as base and the underside  29 ′ (see  FIG. 3   b ) of the magnetic element  29 .  FIG. 6   b  represents the abnormal operating state. Whereas during normal operation in accordance with  FIG. 6   a  there is no contact between the marginal regions  33 ′ of the sheet metal strip  33  and the counter-bearing  34 , in the abnormal operating state according to  FIG. 6   b  the marginal region  33 ′ of the sheet metal strip  33  is supported by, i.e. presses against, the counter-bearing  34  in direction H. 
     In order that handling during mounting is not appreciably limited, the interlocking connection must be designed to have some play. The spacing m in accordance with  FIG. 6   a  allows for play. In a case of abnormal operation in which the limit force of the magnet  29  is overcome, the clothing strip  24  together with its metal backing sheet  33  tilts away from the planar magnetic surface  29 ′ (arrow H in  FIG. 6   b ) and is supported on the counter-bearing  34  (aluminium edge) of the card flat bar. 
     The clearance m is significantly smaller than the spacing a (see  FIG. 2 ) between the card flat clothing  18  and the cylinder clothing  4   a,  so that there is no risk of contact. 
     In normal operation ( FIG. 6   a ), the magnet  29  absorbs all the operating forces and provides for precision support. In the abnormal operating state ( FIG. 6   b ), the interlocking connection safeguards against contact between the card flat clothing  18  and the cylinder clothing  4   a.    
     In another embodiment of the invention shown in 
       FIG. 7 , a card flat bar has an angled side on the counter-bearing  34 ′ and an angled side  33 ″ on the sheet metal strip  33  is provided, the respective angled sides being in interlocking engagement. 
     In a further embodiment, shown in  FIG. 8 , a screw  37  passing through the rib  14   d  is provided as counter-bearing. The screw  37  is removable, and the screw  37  allows a settable depth into the recess  14   f  for the support of the edge region  33 ′ of the sheet metal strip  33 . 
     In yet another embodiment, shown in  FIG. 9 , a flexible metal sheet  38  is mounted on the outside of the rib  14   d,  the limb  38 ′ of which, bent over, serves as counter-bearing. 
       FIG. 10  shows an embodiment in which there is a counter-bearing  39  on the rib  14   d  with which the support layer  25  of the clothing strip  24  co-operates. 
     In the embodiment of  FIG. 11 , a shoulder  25 ′ is present on the supporting element  25 , which shoulder co-operates with the counter-bearing  34 . In this arrangement the turn regions  18 ′ of the clothing  18  are in contact with the magnetic element  29 . 
     The invention has been explained by way of illustration with reference to the embodiments shown. Further arrangements are included in the scope of protection. For example, in the region of the two end faces of the card flat foot  14   b  of the card flat bars  14  there can be provided, in addition or on its own, at least one counter-bearing with which a shoulder on the base  33  and/or on the support member  25  in that region co-operates. The card flat clothing can also be semi-rigid or can be in the form of all-steel clothing, for example sawtooth clothing. 
     Although the foregoing invention has been described in detail by way of illustration and example for purposes of understanding, it will be obvious that changes and modifications may be practised within the scope of the appended claims.