Abstract:
A carding machine includes a main carding cylinder and a doffer to which fiber material is transferred from the main carding cylinder and a fiber removing device positioned downstream of the doffer as viewed in an advancing direction of the fiber material through the carding machine. A gathering device including at least one gathering roll is disposed downstream of the doffer for effecting a negative draft on the fiber material between the doffer and the gathering roll.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims the priority of German Application No. 100 23 011.3 filed May 11, 2000, which is incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     This invention relates to a device which forms an integral part of a carding machine and which processes fiber material, particularly cotton, chemical fibers or the like. The carding machine includes a main carding cylinder followed by a doffer and a pull-off (withdrawing) device for the fiber material. 
     In a known apparatus, as disclosed, for example, in German Offenlegungsschrift (application published without examination) No. 23 64 262, two doffers are provided which take the fiber material off the main carding cylinder. The two doffers are disposed with respect to the carding cylinder and with respect to one another in such a manner that each doffer cooperates with both the carding cylinder and with the other, adjacent doffer and further, a web stripping device cooperates with one of the doffers. The two doffers rotate in opposite directions with respect to the main carding cylinder. An increased production rate is intended by the provision of the two doffers and their arrangement with respect to the carding cylinder and to one another. It is a condition of such a prior art arrangement that the carding cylinder process a fiber quantity which is approximately twice the usual amount handled by a carding cylinder. For such an increased fiber amount the cylinder clothing must be coarser to increase its processing capacity. This disadvantageously reduces the carding quality to a significant extent. 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to provide an improved fiber processing device of the above-outlined type from which the discussed disadvantages are eliminated and with which a fiber web of increased specific weight may be obtained without adversely affecting the carding quality. 
     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 and a doffer to which fiber material is transferred from the main carding cylinder and a fiber removing device positioned downstream of the doffer as viewed in an advancing direction of the fiber material through the carding machine. A gathering device including at least one gathering roll is disposed downstream of the doffer for effecting a negative draft on the fiber material between the doffer and the gathering roll. 
     The fiber gathering device, including at least one fiber gathering (fiber accumulating) roll, results in a negative draft of the fiber material: The gathering rolls accumulate and densify the fiber material, whereby an increased specific weight (quantity per surface or length) of the fiber web is obtained. The fiber web or sliver of increased specific weight is advantageously adapted for further processing, for example, into articles of hygiene. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic side elevational view of a travelling flats-type carding machine including a gathering device according to the invention. 
     FIG. 2 is a schematic side elevational view of a gathering roll disposed between a doffer and a stripping roll. 
     FIG. 3 is a schematic view of two gathering rolls with rpm-controlled drives. 
     FIG. 4 is a schematic side elevational view of a sliver draw unit following a sliver forming device. 
     FIG. 5 is a schematic side elevational view of a calender assembly following a sliver forming device. 
     FIG. 6 shows two crushing rolls and a transverse fiber web pull-off device. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 shows a carding machine CM which may be a high-performance DK 903 model manufactured by Trüftzschler GmbH &amp; Co. KG, Mönchengladbach, Germany. The carding machine CM has a feed roll  1 , a feed table  2  cooperating with the feed roll  1 , licker-ins  3   a ,  3   b ,  3   c , a main carding cylinder  4 , a doffer  5 , a stripping roll  6 , crushing rolls  7 ,  8 , a web guiding element  9 , a sliver trumpet  10 , calender rolls  11 ,  12 , a traveling flats assembly  13  having slowly circulating flat bars  14  (whose speed is between 0.05 and 0.4 m/min) and stationary carding elements  15   a ,  15   b . The doffer  5  is rotated by a symbolically shown drive  5   a . The directions of rotation of the rolls are shown by curved arrows drawn therein. The width of the rolls is between 1 and 1.5 m. The fiber processing direction, that is, the travel direction of the fiber material through the carding machine is indicated at A, while B designates the sliver discharged by the calender rolls  11 ,  12 . The carding machine CM serves particularly for the processing of cotton and/or chemical fibers. 
     The carding machine CM may be supplied with fiber material by an upstream-connected fiber feeder  30  which may be a DIRECTFEED DFK model, manufactured by Trützschler GmbH &amp; Co. KG. 
     According to the invention two gathering rolls  18  and  19  are disposed between the doffer  5  and the stripping roll  6 . The first gathering roll  18  cooperates upstream with the doffer  5  and downstream with the second gathering roll  19 . The doffer  5  and the second gathering roll  19  rotate co directionally, while the first gathering roll  18  rotates in the opposite direction. The circumferential speed of the first gathering roll  18  is less than that of the doffer  5 , whereas the circumferential speed of the second gathering roll  19  is less than that of the first gathering roll  18 . In this manner the fiber material is slowed down and accumulated. The circumferential speed of the doffer  5  may be, for example, 5 m/sec and that of the stripping roll  6  may be 8 m/sec. The circumferential speed of the first and second gathering rolls  18  and  19  may be, for example, 125 m/min and, respectively, 105 m/min at the most. The exit speed of the weight-enhanced sliver B discharged by the calender rolls  11 ,  12  may be approximately 20 m/min or more. Also referring to FIG. 2, the clothing teeth  5   b  of the doffer  5  are oriented rearwardly with respect to its direction of rotation. The clothing teeth  6   b  of the stripping roll  6  are essentially radially oriented. The clothing teeth  18   b  of the first gathering roll  18  are oriented rearwardly relative to its rotary direction whereas the clothing teeth of the second gathering roll  19  are oriented rearwardly with respect to its direction of rotation. By virtue of the gathering device  17  according to the invention, comprising the two gathering rolls  18  and  19  illustrated in FIG. 1, a negative draft, that is, an accumulation of the fiber material is effected at the first gathering roll  18  with respect to the doffer  5  in a ratio of approximately 1:3 to 1:5 and at the second gathering roll  19  with respect to the doffer  5  in a ratio of approximately 1:3 to 1:6. In this manner a heavy sliver B may be made, having a sliver weight of, for example, 80-150 g/m. 
     As shown in FIG. 2, between the doffer  5  and the stripping roll  6  a single gathering roll  18  is provided which cooperates with the doffer  5  and the stripping roll  6 . 
     As shown in FIG. 3, the gathering rolls  18  and  19  are driven by respective rpm-regulated motors  24  and  25  which may be a.c. servomotors and which are coupled to an electronic control and regulating device  26 . Such a control system may set the negative draft (accumulation) of the fiber material to the desired extent. 
     As shown in FIG. 4, the calender rolls  11 ,  12  at the output of the carding machine are followed by a regulated draw unit  20  with which irregularities in the sliver B may be evened, particularly as concerns sliver thickness and structure. The intake roll pair  20   a  and the mid roll pair  20   b  are driven by an rpm-regulated electric motor  21  and the output roll pair  20   c  is driven by an rpm-regulated electric motor  22 . The motors  21  and  22  are connected to an electronic control and regulating device  23 . 
     Turning to FIG. 5, the calender rolls  11 ,  12  of the carding machine are followed by a reinforcing device  27  having two calender rolls  27   a  and  27   b  which serve for reinforcing the fiber web or the sliver B by pressure or profiling. By virtue of this arrangement structural changes are compensated for which may appear in the course of the gathering process and at the same time, the fiber web or sliver B is improved for further processing. The reinforcing device  27  is followed by a processing device  29  which may be an automatic apparatus for making sanitary napkins. To achieve a high output speed and output quantity, advantageously the speed of the sliver B exiting the carding machine and the speed of the sliver C entering the after-connected processing machine  29  are adapted to one another. In such a case no intermediate storage arrangement for the sliver is required. The adaptation is effected by a non-illustrated electronic control and regulating device which is connected with the rpm-regulated drive motors of the carding machine and the processing machine  29 . 
     It is noted that in a carding machine for practicing the invention instead of the traveling flats assembly  13  exclusively stationary carding elements, and instead of the fiber web guiding elements  9  a transverse fiber web pull-off unit  31  as shown in FIG. 6 may be used. 
     In case an intermediate storage arrangement is required, the sliver B may be deposited in a non-illustrated coiler can. 
     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.