Fiber web supporting device in a carding machine
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims the priority of German Application No. P 43 28 431.0 filed Aug. 24, 1993, which is incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     This invention relates to a device disposed between a doffer and a crushing roll pair of a carding machine which treats cotton fiber, chemical fiber or the like. The device has an element which is stationarily disposed underneath a stripper roll which removes fiber material as a fiber web from a doffer. The upper surface of the element is oriented towards a region of the stripper roll and a terminal region of the element is situated in the zone between the doffer and the stripper roll. 
     In a known device the stationary element extends from the doffer to the middle of the stripper roll. The zone between the middle of the stripper roll and the downstream-arranged, superposed crushing rolls is downwardly open. The thin web which is separated at that region by the stripping roll from the doffer runs through a free space until it reaches the nip defined between the two crushing rolls. Upon an increase of the output speed of the card, that is, an increase, for example, to 300 m/min or above, the air stream flowing rearwardly from the crushing rolls interferes with the web travel. The air stream, particularly that which flows rearwardly from the nip between the crushing rolls eventually reaches such a high rearward speed that the unsupported, freely running fiber web is blown back in certain regions. Since the upper crushing roll is close to the stripping roll, the air entrained by the stripping roll may bound back from the upper crushing roll and may also have an adverse effect on the fiber web. The rearwardly directed air streams may press downwardly the thin fiber web, resulting in sagging and tear. Thus, at high delivery speeds the uniform material advance is adversely affected. 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to provide a device of the above-outlined type which eliminates the discussed disadvantages and which, in particular, ensures a disturbance-free transition of the fiber web from the stripping roll to the crushing rolls at high delivery speeds. 
     This object and others to become apparent as the specification progresses, are accomplished by the invention, according to which, briefly stated, the carding machine includes a main carding cylinder; a doffer cooperating with the main carding cylinder for removing fiber material therefrom; a stripping roll cooperating with the doffer for removing a fiber web therefrom; upper and lower cooperating crushing rolls together defining a nip for grasping the fiber web running from the doffer and the stripping roll; and a fiber web supporting and guiding body stationarily positioned underneath the stripping roll. The body has a length dimension extending generally parallel to the rotary axis of the stripping roll and an upper surface for supporting and guiding thereon the fiber web. The upper surface has a width extending generally horizontally and transversely to the stripping roll axis and oppositely located first and second longitudinally extending edge zones. The first edge zone is situated in a region between the doffer and the stripping roll and the second edge zone is situated in a region between the stripping roll and the crushing rolls and is oriented towards the nip defined by the crushing rolls. 
     Thus, the top face of the supporting and guiding body constitutes a backup surface which supports the delicate, freely running fiber web from below. This surface prevents the web from being displaced downwardly and from sagging under the effect of harmful, rearward flowing air streams. Thus, fiber web portions which may be blown rearwardly are caught by the upper surface of the supporting and guiding body and are entrained by the web in the direction of the nip of the crushing roll pair. At the same time, the upper surface of the body positively guides the fiber web in the direction of the nip through the space between the stripping roll and the crushing roll pair. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     FIG. 1 is a schematic side elevational view of a carding machine incorporating the device according to the invention. 
     FIG. 2 is a side elevational view of a preferred embodiment of the invention. 
     FIG. 3 is a side elevational view of another embodiment of the invention shown in an installed state between the doffer, the stripping roll and the crushing roll pair of the carding machine. 
     FIG. 4 is a sectional view taken along line IV--IV of FIG. 3. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Turning to FIG. 1, there is shown therein a carding machine which may be, for example, an EXACTACARD DK 760 model manufactured by Trutzschler GmbH &amp; Co. KG, Monchengladbach, Germany. The carding machine has a feed roller 1 cooperating with a feed table 2, a licker-in 3, a main carding cylinder 4, a doffer 5, a stripping roll 6, crushing rolls 7, 8, a web guide element 9, a trumpet 10, calender rolls 11 and 12 and travelling flats 13. A supporting and guiding body 14 according to the invention is arranged underneath the stripping roll 6. The upper crushing roll 7 immediately adjoins the stripping roll 6. The direction of rotation of the several rolls and rollers are indicated by arcuate arrows. 
     As shown in FIG. 2, the supporting and guiding body 14 has a width measured in the direction A which corresponds to the web travelling direction and a length measured parallel to, for example, the rotary axis of the stripping roll 6. Thus, the length dimension of the body 14 extends parallel to the width dimension of the carding machine and consequently extends perpendicularly to the plane of FIGS. 1, 2 and 3. The cross section of the body 14, taken in a plane perpendicular to the body length, has a generally triangular shape. The principal working part of the body 14 is its upper surface 14a which is slightly concave in the direction A. The radius of curvature of the surface 14a is greater than the radius of the stripping roll 6. The frontal edge zone 14 II  of the body 14 has a relatively sharp edge 14b whereas the rearward edge zone 14 I  is rounded. The edge 14b prevents deposition of impurities, for example, honeydew. The surface 14a is cleaned, for example, of trash, by the overlying, running web. The cross-sectional configuration of the body 14 is adapted to the air flow conditions in the zone between the doffer 5, the stripping roll 6 and the crushing rolls 7, 8. 
     The web supporting and guiding body 14 is shown in its installed state in FIGS. 3 and 4. As shown in FIG. 3, the upper surface 14a of the body 14 is oriented towards the clothing 6&#39; of the stripping roller 6. The edge zone 14 I  is situated in the bight between the doffer 5 and the stripping roll 6. The other edge zone 14 II  is arranged in the region between the stripping roll 6 and the crushing rolls 7, 8, and the edge 14b is oriented toward the nip between the two crushing rolls 7, 8. The body 14 shown in FIGS. 3 and 4 is a one-piece extruded profiled member made, for example, of aluminum, having an inner, longitudinally extending space 14c. 
     For stationarily supporting the body 14 in the carding machine, two holding brackets 15 and 16 are provided which are affixed to inner faces of respective machine frame walls 18a and 18b between which the rolls of the card extend. Both brackets 15 and 16 have a generally triangular orifice complemental to the peripheral outline of the body 14, as may be observed in FIG. 3 for the bracket 15. The frame wall 18b has an aperture which generally conforms to and is aligned with the orifice of the holding bracket 16 so that, for installing the body 14, its longitudinal end portion 14 III  is pushed through the frame plate 18b and the holding bracket 16 to be eventually received by the holding bracket 15 where the end face of the longitudinal end portion 14 III  abuts the inner face of the frame plate 18a. 
     To facilitate insertion of the body 14, a guide bar 17 is provided which, at one end, is affixed to the inner face of the frame plate 18a and has a free end in the zone of the opposite frame plate 18b. Thus, upon insertion of the body 14, the bar 17 penetrates into the inner space 14c of the body 14 and guides the same across the width of the carding machine and assists insertion of the longitudinal end portion 14 III  into the holding bracket 15. As shown in the installed state in FIG. 4, the end portion 14 IV  is surrounded by the holding bracket 16. The body 14 may be secured by non-illustrated screws against displacements relative to the holding brackets 15 and 16. The end portion 14 IV  projects outwardly beyond the frame wall 18b at a distance c whereby a grip is provided, for example, for the purpose of replacing the body 14. 
     The distance a between the stripping roll 6 and the holding bracket 15 is less than the distance b between the stripping roll 6 and the surface 14a of the body 14. In a similar manner, the distance between the stripping roll 6 and the holding bracket 16 is less than the distance between the stripping roll 6 and the surface 14a of the body 14. The holding brackets 15, 16 overlap the respective ends of the stripping roll 6. The end face 15a of the holding bracket 15 is at a distance d from the associated end face 6a of the stripping roll 6, and, similarly, the end face 16a of the holding bracket 16 is at a distance d from the associated end face 6b of the stripping roll 6. In this manner, there is obtained in the zone of the distances a a very narrow gap so that dust, trash, short fibers and the like may not settle at those locations where no clothing 6&#39; is present. 
     The surface 14a of the supporting and guiding body 14, particularly in the edge zone 14 I , serves as a supporting surface for the fiber web, while in the edge zone 14 II  it serves as a guiding surface, directing the fiber web into the nip of the crushing rolls 7, 8. The end zones 14 I  and 14 II  are on opposite sides of a vertical axial plane B of the stripping roll 6. 
     It will be understood that the above description of the present invention is susceptible to various modifications, changes and adaptations, and the same are intended to be comprehended within the meaning and range of equivalents of the appended claims.