CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application claims the benefit of German patent application 10135548.3, filed Jul. 20, 2001, herein incorporated by reference. 
     BACKGROUND OF THE INVENTION 
     The present invention relates generally to open-end spinning devices and, more particularly, to a sliver opening device for an open-end spinning device which comprises a feed device for a rapidly running opening cylinder for opening continuously supplied sliver material. 
     In addition to the rotor spinning method, a sliver is opened by an opening cylinder into individual fibers in other open-end spinning methods such as friction spinning or air spinning. It is customarily desired in such spinning methods in order to avoid fiber compressions that the sliver material be constantly accelerated over its entire path from the feed device of the opening cylinder to the yarn withdrawal device without the draw-off speed having to assume values that are too high. However, lowering the speed of the opening cylinder as desired for this purpose can be associated with significant disadvantages. There is the danger when the speed of the opening cylinder is lowered that the opening function is adversely affected to a significant extent. The number of interventions of opening elements such as needles or sawteeth into the sliver tuft that are necessary for the desired opening of the sliver material into individual fibers can not be achieved. Both the amount of the combed-out fibers as well as the invariability of this amount is insufficient for an unobjectionable yarn. 
     German Patent Publication DE 40 40 102 A1 shows a device for spinning a yarn in which device the sliver end is moved into the fittings by an additional airflow so that an effective opening should be possible even if the speed of the opening cylinder is significantly reduced relative to the speed of opening cylinders customary in rotor spinning devices. Because the sliver end is pressed into the fittings, the combing out of fibers, which is substantially brought about by the side flanks of the teeth or needles, is intensified. The attempt is made in this manner to generate a sufficient frictional entrainment even in the case of rather slower combing speeds, which entrainment reliably draws the fibers out of the sliver end or tuft. However, it turned out that as a result of the aspirated drawing in of the individual fibers, the latter are transported with the circumferential speed of the opening cylinder so that, in spite of the reduced circumferential speed of the opening cylinder, the individual fibers have on the whole the same speed as in the case of traditional opening cylinders and are thus undesirably rapid. 
     German Patent Publication DE 196 10 960 A1 also describes an open-end spinning method in which the individual fibers should no longer be slowed down on their way from the sliver to the yarn. The individual fibers should be subjected immediately after they have been loosened out of the sliver to a precisely determined, mechanically controlled speed. The feed device comprises a very wide feed cylinder and an opening cylinder that is just as wide. This method allows the number of interventions of opening elements into the sliver tuft to be increased. 
     Presenting multiple slivers, e.g., five slivers, adjacent to each other at the same time is disclosed as a possibility for achieving a wide presentation of fibers. The feeding of several slivers to a spinning location results in significant expense. For example, in addition to the expense occasioned by a multiplication of the feed paths with the required feed elements, the space for a corresponding number of spinning cans at each spinning location must be available. This results in an enormous space requirement for a spinning machine with its plurality of spinning locations. Moreover, very high drafts result between the sliver feed and the spun yarn that endanger the uniformity and the maintenance of the yarn fineness. 
     SUMMARY OF THE INVENTION 
     It is accordingly an object of the present invention to improve the feed presentation of sliver to the opening device in an open-end spinning device. 
     The present invention addresses this objective in an open-end spinning device basically comprising an opening device for opening continuously supplied sliver material, the opening device having a feed device for a rapidly running opening cylinder. According to the present invention, a sliver spreading device with at least one cooperating pair of spreading cylinders is arranged in front of the opening device in the feeding direction of the sliver material. The spreading cylinders have circumferential recesses between adjacent circumferential flanges and are arranged in parallel to one another with the flanges of each spreading cylinder engaging into the recesses of the opposing spreading cylinder, whereby the sliver material guided between the pair of spreading cylinders is spread in the axial direction in a cohesive manner over multiple recesses of the spreading cylinders. 
     In this manner, a sliver can be distributed uniformly over the entire working width of the opening cylinder by the spreading cylinders of the present invention arranged in front of the opening device. A relatively thin feed of fiber material can thereby be achieved. The sliver spreading device advantageously requires little space in comparison to multi-step drafting devices. 
     A feed of sliver material can be produced with the present invention which feed can achieve a more precise dosing and an elevated uniformity of the fed amount of sliver. The opening process itself is improved. Undesirably high drafts in the direction of sliver flow and the disadvantages associated with them can be avoided. 
     A compact device for the effective spreading of the sliver in the transversal direction in a narrow space is provided with the sliver spreading device of the present invention. A thin feed of sliver material for the opening cylinder can be achieved that extends over the entire working width of the opening cylinder. This makes it possible to achieve an unobjectionable opening process with a low speed of the opening cylinder and with an opening cylinder that is widened in comparison to the opening cylinder that is customary in rotor spinning. This unobjectionable opening process is distinguished by a high dosing exactitude and high yarn uniformity. 
     The spacing between the particular cooperating spreading cylinders can preferably be periodically varied. This allows the tensile stress acting on the feed of sliver material to be periodically varied and the spreading process to be intensified, accelerated and evened out in this manner. 
     In a preferred embodiment, two successive pairs of spreading cylinders are coupled to one another in such a manner that their spreading cylinder spacings vary in opposite directions, i.e., such that the spacing between one pair of spreading cylinders decreases as the spacing between the other pair of spreading cylinders increases. Preferably, the two spreading cylinder pairs are mechanically coupled and a common drive for producing the periodic variation of the cylinder interval is present, whereby the drive for the periodic varying of the spacings is particularly simple and economical and the spreading effect is reinforced even more. In this manner, a sliver can be spread, e.g., to two to three times the original sliver width. 
     The frequency of the periodic variation of the spreading cylinder spacings is preferably substantially higher than the rotational frequency of the spreading cylinders, e.g., the frequency may be preferably adjusted to a value between 8 Hz and 25 Hz, whereby a high uniformity of the spreading of the sliver material feed results. 
     The recesses can be designed as trapezoidal grooves. Such a form can be produced in a simple manner and forms deflection edges for the sliver guided in a zigzag manner between the particular cooperating spreading cylinders. The sliver is loaded between the deflection edges with an increasing tensile stress and is effectively spread under the action of this tensile stress. 
     Alternatively, the recesses and flanges are designed in such a manner that the flanges of the spreading cylinders form an approximate sinusoidal shape in the axial direction. A more protective spreading is achieved in this manner. 
     In an alternative embodiment of the invention, the spreading cylinders are formed by discs that are fastened to a shaft and whose circumferential surfaces form the flanges. This design can be produced in a simple and economical manner. 
     A limitation to a maximum of two slivers has the result that the sliver material feed will be stretched primarily by transverse spreading and not primarily by longitudinal draft to a thin fiber fleece when it is fed to the opening cylinder. This can improve the uniformity of the sliver material feed. 
     A deflection device in front of the sliver spreading device may be arranged at such a spacing for the sliver drawn out of a can that the sliver travels vertically between the can and the deflection device more than the length of one coil of the sliver in the can. This arrangement makes it possible that a false twist introduced into the sliver by the coiler rotation can turn itself out. Such false twists consist of so-called S twists and of so-called Z twists that can be randomly produced when the sliver is deposited. Thus, the deflection device associated with the sliver spreading device reliably avoids such false twists from running into the spreading cylinder pairs and hindering the spreading process. 
     Further details, features and advantages of the present invention are explained in the following description of a preferred embodiment with reference to the accompanying drawing figures. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic view of a spinning location with a sliver spreading device in accordance with a preferred embodiment of the present invention. 
     FIG. 2 is a simplified side view of the sliver spreading device of FIG.  1 . 
     FIG. 3 is a cross-sectional view through a spreading cylinder pair of the sliver spreading device shown in FIG. 2, taken along line A—A thereof. 
     FIG. 4 is an enlarged cross-sectional view of the spreading cylinders of FIG. 3 showing the cooperative intermeshing thereof. 
     FIG. 5 is another enlarged cross-sectional view, similar to FIG. 4, through another embodiment of a pair of spreading cylinders with a sinusoidal profile. 
     FIG. 6 is a cross-sectional view through another embodiment of a pair of spreading cylinders which comprise discs forming the flanges and recesses. 
     FIG. 7 is a side view of a sliver spreading device with cooperating spreading cylinders whose spacing from each other can be periodically varied. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the accompanying drawings and initially to FIG. 1, sliver  1  is drawn off out of can  2  at the spinning location shown in FIG. 1, travels via deflection roller  3  of deflection device  4  and is supplied by guide  5  to sliver spreading device  6 . The spacing between the axis of deflection roller  3  and can  2  is somewhat more than the sliver length of one coiled rotation of the sliver stored within the can. Sliver  1  hangs freely on this stretch and false twists occurring in an isolated manner in sliver  1  can rotate themselves out. Sliver  1  runs through three pairs of cylinders formed by spreading cylinders  7 ,  8 ,  9 ,  10 ,  11 ,  12  and is fed in a spread state in the form of a thin sliver fleece  13  to opening device  14 . Feed trough  15  presses spread sliver  1  against draw-in cylinder  16  and forms with draw-in cylinder  16  a clamping position that retains the end of sliver  1 , the so-called sliver tuft. Opening cylinder  17  combs out the sliver tuft and opens the sliver to the individual fibers. Opening cylinder  17  thereby rotates in the direction of arrow  18 . The fibers are taken by takeoff cylinder  19  standing under a vacuum and combined to a narrow, small sliver. The direction of rotation of takeoff cylinder  19  is indicated by arrow  20 . Takeoff cylinder  19  and clamping roller  21  form a clamping line through which the small sliver is run. 
     Air spinning device  22  generates an air vortex that serves for sliver formation. Such air spinning devices are known, e.g., from German Patent Publication DE 196 10 960. Sliver  23  passes draw-off device  24  and is transported to a winding head not shown for reasons of simplicity. 
     Sliver spreading device  6  of FIG. 2 is enlarged relative to FIG.  1  and is shown in more detail. Sliver  1  is deflected through guide  5  and drawn into the first cylinder pair formed by spreading cylinders  7 ,  8  and is spread thereby to become thinner as a result of the spreading. Sliver  1  subsequently travels through spreading cylinders  9 ,  10  of the second spreading cylinder pair and finally through spreading cylinders  11 ,  12  of the third spreading cylinder pair and is supplied as a thin sliver  1  spread over the entire working width to draw-in cylinder  16  that forms a clamping line with feed trough  15 . A rapidly running opening cylinder  17  combs the fibers out of the end of sliver  1 , which end is designated as sliver tuft  25 , and opens sliver  1  thereby into individual fibers. 
     Lower spreading cylinders  8 ,  10 ,  12  are connected to gears  26 ,  27 ,  28  such that they rotate in unison with one another. Intermediate gears  29 ,  30  establish a drive connection between gears  26 ,  27 ,  28  of lower spreading cylinders  8 ,  10 ,  12 . Intermediate gear  30  is connected to belt disk  31  such that it rotates in unison with it, which belt disk is driven by drive belt  32  via belt disk  33 . Belt disk  33  is connected in turn to draw-in cylinder  16  such that it rotates in unison with it. Belt disk  33  is driven by motor  35  via drive belt  34 . The translation between draw-in cylinder  16  and lower spreading cylinders  8 ,  10 ,  12  is selected in such a manner that the circumferential speed of draw-in cylinder  16  is equal to that of spreading cylinders  8 ,  10 ,  12 . 
     Shaft  36  of upper spreading cylinder  9  is fastened to one arm of angle lever  37 . Angle lever  37  can pivot about shaft  38 , that is stationary relative to housing  40 , and comprises bolt  39  fastened to the other arm. Bolt  39  engages into oblong hole  41  of coupling rod  42 . In the same manner, upper spreading cylinders  7 ,  11  are pivotably supported on angle levers  43 ,  44 . Bolts  45 ,  46  of angle levers  43 ,  44  also each engage into an oblong hole of coupling rods  47 ,  48 . 
     Coupling rod  42  is pivotably inserted by its end onto bolt  45  and coupling rod  48  in the same manner onto bolt  39  so that the three angle levers  37 ,  43 ,  44  are articulated to each other and can pivot in common. Upper spreading cylinders  7 ,  9 ,  11  can be raised off of lower spreading cylinders  8 ,  10 ,  12  by pivoting angle levers  37 ,  43 ,  44  counterclockwise in order, e.g., to be able to insert new slivers. 
     Spiral springs  52 ,  53 ,  54  are suspended on bolts  45 ,  39 ,  46  of angle levers  43 ,  37 ,  44  and on bolts  49 ,  50 ,  51 , that are fastened on coupling rods  47 ,  42 ,  48 . If coupling rods  42 ,  47 ,  48  are drawn manually to the right in the view of FIG. 2 after the insertion of slivers, the oblong holes in coupling rods  42 ,  47 ,  48  shift relative to bolts  39 ,  45 ,  46 , and bolts  39 ,  45 ,  46  and therewith angle levers  37 ,  43 ,  44  are loaded with a tractive force by means of spiral springs  52 ,  53 ,  54 . 
     Under the action of this tractive force, angle levers  37 ,  43 ,  44  pivot clockwise until upper spreading cylinders  7 ,  9 ,  11  have reached an end position. In this end position coupling rods  42 ,  47 ,  48  are fixed by locking lever  55 . Locking lever  55  can pivot about bolt  49  and has a nose  56  which engages in a hooking manner on housing  40 . 
     In order to manually raise upper spreading cylinders  7 ,  9 ,  11 , lever knob  57  is grasped and locking lever  55  is pivoted upward, as a consequence of which nose  56  is lifted out of housing  40  and the fixation of coupling rods  42 ,  47 ,  48  is cancelled. Angle levers  37 ,  43 ,  44  are pivoted counterclockwise and upper spreading cylinders  7 ,  9 ,  11  are raised by a subsequent moving of lever knob  57  to the left in the view of FIG.  2 . 
     If a sliver thickening or sliver rotation travels into a spreading cylinder pair the upper spreading cylinders  7 ,  9 ,  11  can yield upwards. The deflection takes place counter to the tensile stress applied by the particular spiral springs  52 ,  53 ,  54  in the framework of the play limited by the dimensions of the oblong holes of coupling rods  42 ,  27 ,  48 . 
     FIG. 3 shows a section through the second spreading cylinder pair of sliver spreading device  6  shown in FIG.  2 . The grooves and flanges of the two spreading cylinders  9 ,  10  mesh into each other and form an intermediate space having a zigzag form. The spacing of spreading cylinders  9 ,  10  is dimensioned in such a manner that a sliver  1  of 7 ktex can be drawn into the intermediate space without raising upper spreading cylinder  9 . Shaft  58  of lower spreading cylinder  10  is supported on housing  40  and is driven via gear  27 . Spreading cylinder  10  comprises lateral edges  59 ,  60  on which upper spreading cylinder  9  rests with its edges  61 ,  62 . Upper spreading cylinder  9  is rotatably supported on shaft  63 . Shaft  63  is permanently connected to angle lever  37 . Spiral spring  53  attacks bolt  39  fastened to the upper lever arm of angle lever  37 . The working width of the cylinder pairs is adapted to the working width of draw-in cylinder  16 . Sliver  1  is already extensively spread over the width of spreading cylinders  9 ,  10  in the view of FIG.  3 . After the spreading by the third spreading cylinder pair, sliver  1  can be presented to draw-in cylinder  16  in a form spread over the entire working width thereof. 
     FIG. 4 shows the intermediate space between spreading cylinders  9 ,  10  in an enlarged view. Flanges  64  of lower spreading cylinder  10  engage into grooves  65  of upper spreading cylinder  9  and flanges  66  of upper spreading cylinder  9  engage into grooves  67  of lower spreading cylinder  10 . Sliver  1  runs in a zigzag manner in the intermediate space between the two spreading cylinders  9 ,  10  and is subjected to a tensile stress upon running into the cylinder pair in the area between flanges  64  and flanges  66 , which causes it to be spread. 
     The spreading process of sliver  68  can be completed in a more protective manner with the embodiment shown in FIG.  5 . To this end, the surface of upper spreading cylinder  69  and the surface of lower spreading cylinder  70  have an approximately sinusoidal shape, viewed in the axial direction. 
     FIG. 6 shows an alternative embodiment of the subject matter of the invention. Sliver  71  is conducted through a spreading cylinder pair in which the upper spreading cylinder  72  as well as the lower spreading cylinder  73  comprise disks  74 ,  75  that are fastened to a shaft  76 ,  77  and whose circumferential surfaces form flanges  99 ,  100 . Recesses  97 ,  98  are formed between disks  74 ,  75 . This design of spreading cylinders  72 ,  73  can be manufactured simply and economically. 
     FIG. 7 shows a side view of sliver spreading device  78  with upper spreading cylinders  79 ,  81  that move up and down and lower, stationary spreading cylinders  80 ,  82 . The opening device with draw-in cylinder  16  is described above in conjunction with FIG.  2 . Sliver  1  passes guide  5  and deflection cylinder  83  before it is fed to the first spreading cylinder pair formed by upper spreading cylinder  79  and lower spreading cylinder  80 . Before it is presented to draw-in cylinder  16 , the sliver  1  travels through a second spreading cylinder pair formed by upper spreading cylinder  81  and lower spreading cylinder  82 . The height of the stationarily supported, lower spreading cylinders  80 ,  82  is selected in such a manner that sliver  1  can run above spreading cylinders  80 ,  82  when it is tautly drawn between deflection cylinder  83  and draw-in cylinder  16 . 
     Shafts  84 ,  85  of spreading cylinders  79 ,  81  are fastened to angle lever  86 . The two lower spreading cylinders  80 ,  82  are stationarily mounted on housing  87 . The mounting corresponds to the mounting of spreading cylinders  8 ,  10 ,  12  shown in FIG.  2 . Angle lever  86  and pivot lever  88  shown in dotted lines are connected to shaft  89  in such a manner that they rotate in unison with it and can pivot together about the axis of rotation of shaft  89 . One end of pivot lever  88  can be moved back and forth by connecting rod  90 . The other end of connecting rod  90  engages crank disk  91  driven by motor  92 . The speed of crank disk  91  is between 500 rpm and 1,500 rpm. The crank drive is designed as a buffer element in such a manner that when sliver thickenings or sliver twists occur, no blockage occurs. 
     Upper spreading cylinders  79 ,  81  move periodically up and down as a function of the speed of crank disk  91 . The spreading action exerted on sliver  1  is significantly reinforced by the high-frequency movement. 
     The lower spreading cylinders  80 ,  82  are put in rotation by drive belt  93  via intermediate gear  94  and gears  95 ,  96 . Drive belt  93  also drives deflection cylinder  83 . The translation ratios are selected so that deflection cylinder  83  as well as spreading cylinders  79 ,  80 ,  81 ,  82  and draw-in cylinder  16  have the same circumferential speed. 
     Sliver  1  is separated out of the grooves upon each upward movement of upper spreading cylinders  79 ,  81  in the particular spreading cylinder pair. The new contact position between sliver material and the flanges is usually shifted somewhat laterally during the downward movement of spreading cylinders  79 ,  81 . Sliver  1  is spread as a result not only more effectively but also more uniformly. 
     It will therefore be readily understood by those persons skilled in the art that the present invention is susceptible of broad utility and application. Many embodiments and adaptations of the present invention other than those herein described, as well as many variations, modifications and equivalent arrangements, will be apparent from or reasonably suggested by the present invention and the foregoing description thereof, without departing from the substance or scope of the present invention. Accordingly, while the present invention has been described herein in detail in relation to its preferred embodiment, it is to be understood that this disclosure is only illustrative and exemplary of the present invention and is made merely for purposes of providing a full and enabling disclosure of the invention. The foregoing disclosure is not intended or to be construed to limit the present invention or otherwise to exclude any such other embodiments, adaptations, variations, modifications and equivalent arrangements, the present invention being limited only by the claims appended hereto and the equivalents thereof.
An open-end spinning device with an opening device for opening continuously supplied sliver material by means of a rapidly running opening cylinder, which opening device is arranged in front of a sliver spreading device ( 78 ) with cooperating pairs of spreading cylinders. The spreading cylinders ( 79, 80, 81, 82 ) comprise flanges that engage into recesses of the opposing spreading cylinder. The spacing between the particular cooperating spreading cylinders ( 79, 80, 81, 82 ) can be periodically varied. An unobjectionable opening process with a low speed of the opening cylinder and with a widened opening cylinder can be achieved with the sliver spreading device ( 78 ) of the invention which process is associated with a high-precision dosing and high yarn uniformity.