Abstract:
The invention proceeds from a converter cutting device for a converter which is provided for converting at least one endless fiber into cut fibers, having at least one cutting unit which can be driven rotationally about a rotational axis and comprises at least one cutting means with at least one blade. It is proposed that the cutting means encloses a cutting angle which does not equal 0 degrees with a plane which is oriented perpendicularly with respect to the rotational axis.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a U.S. national stage application of PCT/EP2011/004575 filed on Sep. 12, 2011, and claims priority to, and incorporates by reference, German patent application No. 10 2010 045 702.7 filed on Sep. 16, 2010. 
     PRIOR ART 
     DE 10 2007 052 586 has already disclosed a converter cutting device for a converter which is provided for converting a continuous fiber into cut fibers, with a cutting unit which can be driven in rotation about an axis of rotation and which comprises a cutting means with a cutting edge. 
     SUMMARY 
     The invention proceeds from a converter cutting device for a converter which is provided for converting at least one continuous fiber into cut fibers, with at least one cutting unit which can be driven in rotation and which comprises at least one cutting means with at least one cutting edge. 
     It is proposed that the cutting means forms a cutting angle unequal to 0 degrees with a plane which is oriented perpendicularly to the axis of rotation. Wear of the cutting unit can thereby be reduced. Moreover, a cutting performance of the converter cutting device can consequently be maintained, as compared with known converter cutting devices, with the result that a converter can be provided which has an advantageously long service life and an advantageously high processing speed. 
     A “cutting unit” is to be understood in this context to mean, in particular, a group of components which are connected fixedly to one another and which, overall, can be driven in rotation. A “cutting means” is to be understood, in particular, to mean a component of the cutting unit which has the at least one cutting edge. A “cutting edge” of the cutting means is to be understood in this context to mean, in particular, a side edge of the cutting means, in which side edge two faces of the cutting means are contiguous to one another at an acute angle. The cutting edge can therefore be described ideally by a line which runs along the side edge forming the cutting edge. The cutting edge has a length of at least 5 millimeters, preferably a length of at least 10 millimeters and especially advantageously a length of approximately 20 millimeters to 30 millimeters, even greater lengths basically being conceivable. The cutting edge is in this case advantageously designed as a straight line. Basically, however, the cutting edge may also be curved. The word “provided” is to be understood, in particular to mean specially equipped and/or designed. 
     A “cutting angle” which the cutting means forms with the plane is to be understood in this context to mean, in particular, an angle which the cutting means forms, at least in the region of the cutting edge, with the plane perpendicular to the axis of rotation. The cutting angle is preferably designed as an angle which an underside of the cutting means forms with a direction of movement of the cutting means in the plane. A “direction of movement” is to be understood in this context to mean, in particular, a direction vector which defines a provided cutting movement direction of any point on the cutting edge at any point in time. In this case, in particular, it is advantageous if the cutting means has the cutting angle unequal to 0 degrees at at least one point on the cutting edge, but preferably over an entire length of the cutting edge. What can be achieved thereby is that the entire cutting edge forms an angle unequal to 0 degrees with the plane perpendicular to the axis of rotation. To determine the cutting angle, advantageously a point on the cutting edge is used which is at the shortest distance from the axis of rotation of the cutting unit. In principle, the cutting angle may have different angles along an extension of the cutting edge. 
     Further, it is proposed that the at least one cutting means has a cutting angle of approximately 1 degree. By means of a cutting angle of approximately 1 degree, especially low wear of the cutting edge can be achieved, with the result that an especially long service life can be achieved. The word “approximately” is to be understood in this context to mean, in particular, that the cutting angle lies in a range of between 0.5 degrees and 1.5 degrees and especially advantageously in a range of between 0.8 and 1.2 degrees. 
     Furthermore, it is proposed that the cutting unit comprises at least one cutting support element which defines the cutting angle unequal to zero for the cutting means. The cutting means can thereby have a simple configuration, and in this case, in particular, conventional cutting means can continue to be used. A “cutting support element” is to be understood in this context to mean, in particular, an element which has for the cutting means a defined bearing surface, the inclination of which defines the cutting angle. 
     Moreover, it is proposed that the cutting edge comprises an inner point and an outer point, between which it has an axial cutting edge offset. Especially advantageous bearing contact of the cutting element against a countercutting element can thereby be achieved, with the result that the continuous fiber can be cut reliably. An “axial cutting edge offset” is to be understood in this context to mean, in particular, that the inner point of the cutting edge is offset in the axial direction with respect to the outer point of the cutting edge. “Axial direction” is to be understood in this context to mean, in particular, a direction parallel to the axis of rotation of the cutting unit. An “inner point” of the cutting edge is to be understood to mean a point on the cutting edge which is at the shortest distance from the axis of rotation of the cutting unit. An “outer point” of the cutting edge is to be understood to mean a point on the cutting edge which is at the longest distance from the axis of rotation of the cutting unit. 
     In a development of the invention, it is proposed that the converter cutting device has at least one fixed countercutting unit with at least one countercutting means which forms a countercutting edge. An especially advantageous countercutting edge can thereby be provided. The word “fixed” is to be understood in this context to mean, in particular, that the countercutting unit is fixed at least during normal operation. In principle, at least the countercutting means may be adjustable. 
     In an advantageous refinement, the cutting edge and the at least one countercutting edge are provided for a shear cut. An especially advantageous cutting action can thereby be achieved. A “shear cut” is to be understood in this context to mean, in particular, that an intersection point of the cutting edge with the countercutting edge travels during a cutting movement, preferably the intersection point traveling from the inner point of the cutting edge successively in the direction of the outer point of the cutting edge. An “intersection point” is to be understood in this context to mean, in particular, a point at which the cutting edge and the countercutting edge intersect in a plane of projection perpendicular to the axis of rotation of the cutting unit. 
     Preferably, the at least one countercutting means forms a cutting angle of approximately 0 degrees with a plane which is oriented perpendicularly to the axis of rotation. An especially advantageous shear cut can thereby be achieved. A cutting angle of approximately 0 degrees is to be understood in this context to mean, in particular, that the countercutting edge of the countercutting means runs in a plane which is oriented perpendicularly to the axis of rotation of the cutting unit. In this context, “approximately” is to be understood to mean a deviation of at most 0.5 degrees and especially advantageously a deviation of at most 0.2 degrees. 
     Moreover, it is advantageous if the cutting edge and the countercutting edge are at a maximum cutting distance which is shorter than the cutting offset of the cutting edge. An especially advantageous cut can thereby be achieved. What can thereby be achieved, in particular, is that the cutting edge bears against the countercutting edge over at least one region of the cutting movement, with the result that an especially clean and reliable cut of the continuous fiber can be implemented. A “cutting distance” is to be understood in this context to mean, in particular, a distance between the inner point of the cutting edge and the countercutting edge. The cutting distance is advantageously greater than zero and lower than 0.1 millimeters, a cutting distance lower than 0.01 millimeters being especially advantageous. 
     In a further refinement, it is proposed that the converter cutting device comprises at least one continuous fiber feed which is assigned to the at least one countercutting edge and which is provided for introducing at least two continuous fibers simultaneously into a cutting space in the region of the countercutting edge. An especially high cutting capacity can thereby be achieved, since, by means of a single shear cut, the at least two continuous fibers can be cut simultaneously. In this context, “in the region of the countercutting edge” is to be understood to mean, in particular, that the continuous fibers are introduced into the cutting space directly in front of the countercutting edge, as a result of which, during a cutting movement, the two continuous fibers are located between the cutting edge and the countercutting edge. 
     Preferably, the continuous fiber feed has at least two fiber outlet orifices assigned to the one countercutting edge. An especially advantageous configuration can thereby be achieved. In this context, “assigned” is to be understood to mean, in particular, that a continuous fiber led through the fiber outlet orifice is cut by means of the countercutting edge. 
     Further, a converter which is provided for converting at least one continuous fiber into cut fibers, with a converter cutting device according to the invention, is proposed. 
     Preferably, in this case, the converter cutting device has at least three countercutting units distributed about an axis of rotation of the cutting unit. A converter can thereby be provided in which, during a single rotational movement of the cutting unit once about its axis of rotation, a plurality of continuous fibers, in particular continuous fibers of different thickness and/or different type, are cut simultaneously, with the result that an especially advantageous configuration of a converter, particularly with a high cutting capacity, can be implemented in a simple way. Preferably, the converter cutting device comprises a central cutting space, in which the rotatably arranged cutting unit and the at least three fixed countercutting units are arranged. Especially preferably, the at least three countercutting units are distributed uniformly about the axis of rotation of the cutting unit. 
     Furthermore, it is advantageous if the converter has a fiber-draw-forward device for feeding at least one continuous fiber, which device has at least one roller draw-forward unit and at least one compressed-air draw-forward unit. Advantageously simple conveyance of the at least one continuous fiber can thereby be achieved, with the result that the converter can have a reliably high cutting capacity. Preferably, in this case, the compressed-air conveying unit is provided for threading in the continuous fiber, with the result that a continuous fiber can be threaded into the fiber-draw-forward device in a simple way. 
     Further, it is proposed that the compressed-air draw-forward unit has at least one entry-side guide tube and one exit-side guide tube. An advantageous configuration of the fiber-draw-forward device can thereby be achieved, which makes it possible, in particular, to have reliable normal operation and to thread in the continuous fiber in a simple way. 
     Moreover, it is advantageous if the fiber-draw-forward roller unit has at least one draw-forward roller which is arranged between the guide tubes of the compressed-air draw-forward unit. The fiber-draw-forward unit can thereby be configured especially advantageously. In particular, reliable transport of the continuous fiber can be achieved as a result, while at the same time a draw-forward speed can advantageously be set. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further advantages may be gathered from the following drawing description. The drawings illustrate an exemplary embodiment of the invention. The drawings, description and claims contain numerous features in combination. A person skilled in the art will expediently also consider the features individually and combine them into appropriate further combinations. 
         FIG. 1  is a cross sectional view through a cutting unit of a converter cutting device, 
         FIG. 2  is a view of the cutting unit in a perspective illustration, 
         FIG. 3  is a top view of the cutting unit, 
         FIG. 4  is an overall view of an underside of the converter cutting device, and 
         FIG. 5  is a view of a fiber-draw-forward device for feeding a continuous fiber. 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1 to 4  show a converter which is provided for converting endless fibers into cut fibers. The converter comprises a converter cutting device  10  and a fiber-draw-forward device  37 . The fiber-draw-forward device  37  feeds the continuous fibers to the converter cutting device  10  at an adjustable draw-forward speed. The converter cutting device  10  cuts the continuous fibers into short cut fibers. 
     The converter cutting device  10  comprises a rotatably arranged cutting unit  12  and a fixed countercutting unit  19 . Further, the converter cutting device  10  comprises a drive  43  for the cutting unit  12 . The drive  43  comprises a driving machine, not illustrated in any more detail, with a drive shaft  44 , to which the cutting unit  12  is connected. The cutting unit  12  forms a cutting head which can be driven in rotation by means of the driving machine. 
     The cutting unit  12  is of multipart form. The cutting unit  12  comprises a basic body  45  which provides a receptacle for mounting the drive shaft  44  of the driving machine. Further, the cutting unit  12  comprises a cutting means  13  which is connected fixedly to the basic body  45 . To tie up the cutting means  13  to the basic body  45 , the cutting unit  12  comprises a cutting edge receptacle with a cutting edge support element  16  and with a clamp fastening  46 . Moreover, the cutting unit  12  comprises a cover  47  which covers the cutting edge receptacle. 
     The clamp fastening  46  comprises a clamping disk  48  and a screw  49  for providing a clamping force. The cutting means  13  of the cutting unit  12  is tension-mounted between the clamping disk  48  of the clamp fastening  46  and the cutting support element  16 . The screw  49  of the clamp fastening  46  is screwed into the basic body  45 . Starting from a head of the screw  49 , the screw  49  passes in succession through the clamping disk  48 , the cutting means  13  and the cutting edge support element  16  before it engages into a thread in the basic body  45 . 
     The basic body  45  and the cover  47  have an essentially round cross section in a cross-sectional plane running perpendicularly to an axis of rotation  36  of the cutting unit  12 . The cutting means  13  of the cutting unit  12  projects laterally beyond the cross section of the basic body  45  with respect to the axis of rotation  36 . The cutting means  13  is in this case fastened decentrally to the basic body  45 . In particular, the cutting edge receptacle with the clamp fastening  46  is arranged so as to be offset with respect to the axis of rotation  36 . 
     The cutting means  13  and the cutting receptacle form an unbalance. The cover  47  which covers the cutting receptacle forms a counterweight. The cutting unit  12  thus has a symmetrical weight distribution with respect to the axis of rotation  36 . 
     The screw  49  of the clamp fastening  46  is arranged approximately centrally between the axis of rotation  36  and a margin of the basic body  45 . The cutting receptacle extends over a region which occupies approximately half of the basic body  45 . The cutting means  13  of the cutting unit  12  is thus arranged asymmetrically with respect to the axis of rotation  36 . 
     The cutting means  13  has two blunt side edges  50 ,  51  and at least one sharp side edge  52 . A fourth side edge, not illustrated in any more detail, may likewise be sharp. The two blunt side edges  50 ,  51  are arranged opposite one another. They run virtually parallel to one another. The two sharp side edges, of which only the side edge  52  is illustrated, are likewise arranged opposite one another. The blunt side edges  50 ,  51  and the sharp side edge  52  are respectively at an angle of approximately 45 degrees and of 135 degrees to one another. The cutting means  13  thus has a shape which corresponds approximately to a parallelogram. 
     The two blunt side edges  50 ,  51 , between which the sharp side edge  52  is arranged, project out of the basic body  45 . The sharp side edge  52  is therefore arranged outside the basic body  45  and forms a cutting edge  14 , by means of which the continuous fiber is cut. 
     During cutting operation, the cutting unit  12  is driven in rotation. A cutting movement is consequently executed as a rotational movement about the axis of rotation  36  of the cutting unit  12 . A direction of movement  53  in which the cutting means  13  is moved is therefore directed in the circumferential direction with respect to the axis of rotation  36 . The provided direction of movement  53  which the cutting means  13  executes is therefore defined by a tangent of a circle which has the axis of rotation  36  as its center and which the axis of rotation  36  passes perpendicularly through. 
     The cutting means  13  forms an angle unequal to 0 degrees with the provided direction of movement  53 . The cutting means  13  therefore forms a cutting angle  15  unequal to 0 degrees with a plane which is oriented perpendicularly to the axis of rotation  36 . To set the cutting angle  15 , the entire cutting means  13  is tilted about a tilting axis  61  which runs in the plane parallel to the axis of rotation  36 . Basically, however, it is also conceivable that the cutting means  13  has the cutting angle  15  unequal to 0 degrees in subregions only, for example in the case of a cutting means of curved form. In particular, in this case, it is conceivable that the cutting means  13  has the cutting angle unequal to 0 degrees solely in the region of the cutting edge, for example as a result of corresponding grinding in the region of the cutting edge. 
     The cutting means  13  is of plate-like form, that is to say has an essentially constant thickness which is markedly lower than a length of the side edges  50 ,  51 ,  52 . The cutting means  13  therefore has two main faces which run parallel to one another and which form a top side  54  and an underside  55  of the cutting means  13 . The underside  55  of the cutting means  13  confronts the countercutting unit  19 . 
     The cutting angle  15  of the cutting means  13  is defined by the underside  55 . The cutting angle  15  can therefore be illustrated by an extension of the underside  55  in a cross-sectional plane in which lies a direction vector defining the direction of movement  53 . The main axis of rotation  36 , of which the projection in the cross-sectional plane can be illustrated, runs perpendicularly to the direction of movement  53  in this cross-sectional plane. The cross-sectional plane for determining the cutting angle  15  is therefore defined by the direction of movement  53  and the projection of the axis of rotation  36 . 
     The tilting axis  61  runs perpendicularly to the axis of rotation  36 . The side edge  50  runs parallel to the tilting axis  61 . The tilting axis  61  itself therefore has an extension which corresponds virtually to a radial extension with respect to the axis of rotation  36 . A minimum distance between the tilting axis  61  and the axis of rotation  36  is virtually zero. 
     The cutting edge  14  of the cutting means  13  is linear. The cutting edge  14  has a length of approximately 20 millimeters. The cutting means  13  therefore has the same cutting angle  15  over the entire length of the cutting edge  14 . The cutting angle  15  which the cutting means  13  has amounts to approximately 1 degree. With respect to the cutting edge  14 , the cutting angle  15  is negative, that is to say it has the effect that, during a cutting movement, a distance between the cutting edge  14  and a countercutting edge  25  becomes shorter at an intersection point. 
     The two blunt side edges  50 ,  51  of the cutting means  13  form a front side and a rear side of the cutting means  13 . During a cutting movement, first, a point on the side edge  50  designed as the front side runs over a fixed point, for example, on the countercutting unit  19  before an equivalent point on the side edge  51  designed as the rear side runs over this point. 
     In a plane perpendicular to the axis of rotation  36  of the cutting unit, the cutting edge  14  has an extension which is oriented obliquely to the direction of movement. The cutting edge  14  therefore comprises an inner point  17 , which is at the shortest distance from the axis of rotation  36 , and an outer point  18 , which is at the longest distance from the axis of rotation  36 . 
     The cutting angle  15 , defined as the angle which the underside  55  of the cutting means  13  forms with the plane perpendicular to the axis of rotation  36 , specifically starting from the inner point  17  and parallel to the direction of movement  53 , has the effect that the cutting edge  14  likewise forms an angle unequal to 0 degrees with the plane perpendicular to the axis of rotation. Owing to the negative cutting angle  15 , the cutting edge  14 , starting from the inner point  17 , runs obliquely in the direction of the countercutting unit  19 . The inner point  17  of the cutting edge  14  is offset axially along the axis of rotation  36  with respect to the outer point  18  of the cutting edge  14 . The cutting edge  14  therefore has a cutting offset  28  which corresponds to an axial distance between the two points  17 ,  18  of the cutting edge  14 . 
     The countercutting unit  19  comprises a countercutting means  22  which has a top side which confronts the cutting unit  12  and which runs perpendicularly to the axis of rotation  36  of the cutting unit  12 . The countercutting means  22  therefore forms a cutting angle of 0 degrees with a plane which is oriented perpendicularly to the axis of rotation  36 . The top side of the countercutting means  22  in this case runs parallel to the plane which is oriented perpendicularly to the axis of rotation  36  of the cutting unit  12 . The countercutting means  13  forms a countercutting edge  25  which runs in the radial direction with respect to the axis of rotation  36  of the cutting unit  12 . 
     A cutting distance between the cutting means  13  of the cutting unit  12  and the countercutting means  22  of the countercutting unit  19  is shorter than the cutting offset  28  of the cutting means  13 . The cutting distance is in this case defined as a distance by which the inner point  17  of the cutting edge  14  is spaced apart from the countercutting edge  25 . The cutting distance amounts to approximately 0.01 millimeters. 
     During a cutting movement, the inner point  17  runs at a distance over the countercutting edge  25 . As the cutting movement continues, all the points between the inner point  17  of the cutting edge  14  and the outer point  18  of the cutting edge  14  run over the countercutting edge  25  in succession. The cutting movement is consequently designed as a shear cut for which the cutting edge  14  and countercutting edge  25  are provided. 
     Owing to the negative cutting angle  15 , during the cutting movement one of the points which are arranged between the inner point  17  and the outer point  18  of the cutting edge  14  comes into contact with the countercutting edge  25 . In a continuation of the cutting movement, the negative cutting angle  15  causes the cutting edge  14  to exert pressure force upon the countercutting edge  25 . In the course of the cutting movement, in this case a distance between the cutting edge  14  and the countercutting edge  25  is equal to zero. 
     The converter cutting device  10  comprises a cutting space  32  in which the cutting unit  12  and countercutting unit  19  are arranged. Further, the converter cutting device  10  comprises a continuous fiber feed  29  which is provided for introducing two or more continuous fibers simultaneously into the cutting space  32 . The continuous fiber feed  29  is in this case assigned to only the one countercutting edge  25  of the countercutting unit  19 , that is to say the continuous fibers introduced simultaneously into the cutting space are cut by the countercutting edge  25  during a cutting movement of the cutting edge  14 . 
     The continuous fiber feed  29  comprises an outlet element  56  into which three fiber outlet orifices  33 ,  34 ,  35  are introduced. The three fiber outlet orifices  33 ,  34 ,  35  are arranged along the countercutting edge of the countercutting unit  19 . The fiber outlet orifices  33 ,  34 ,  35  are in this case arranged in the radial direction one behind the other in a region in front of the countercutting edge  25 , with the result that they are cut by means of a single shear cut during a cutting movement. 
     The outlet element  56  is exchangeable. The outlet element  56  used in the exemplary embodiment illustrated comprises the three fiber outlet orifices  33 ,  34 ,  35  which have a different size. In principle, instead of the outlet element  56 , an outlet element may also be used which has only two or only one fiber outlet orifice. In this case, in principle, fiber outlet orifices with different diameters may also be used. Both a number of continuous fibers and a diameter of the continuous fibers can be adapted to different requirements by means of the exchangeable outlet element  56 . 
     The converter cutting device  10  comprises, in addition to the countercutting unit  19  described, two further countercutting units  20 ,  21  which are of similar design. The converter cutting device  10  therefore comprises the three similarly designed fixed countercutting units  19 ,  20 ,  21  and the cutting unit  12  which can be driven in rotation. 
     The three countercutting units  19 ,  20 ,  21  are arranged symmetrically about the axis of rotation  36 . The countercutting units  19 ,  20 ,  21  in each case comprise a countercutting means  22 ,  23 ,  24  which form in each case a countercutting edge  25 ,  26 ,  27  of the corresponding countercutting unit  19 ,  20 ,  21 . The countercutting edges  25 ,  26 ,  27  are arranged here so as to be in each case offset at 120 degrees with respect to one another. The three countercutting means  22 ,  23 ,  24  are arranged in the central cutting space  32  of the converter cutting device  10 . A rotational movement of the cutting unit  12  over 360 degrees leads to a shear cut on each of the countercutting units  19 ,  20 ,  21 . 
     To draw the continuous fibers forward, the fiber-draw-forward device  37  of the converter comprises a roller draw-forward unit  38  and a compressed-air draw-forward unit  39 . The roller draw-forward unit  38  has a driven draw-forward roller  42  and a pressure roll  57 . The compressed-air draw-forward unit  39  comprises a compressed-air feed, by means of which an air stream is generated along a conveying direction  60  of the continuous fibers. 
     The roller draw-forward unit  37  comprises an adjusting mechanism  58 , by means of which the pressure roll  57  can be lifted off from the draw-forward roller  42 . The compressed-air draw-forward unit  39  comprises two guide tubes  40 ,  41  which are arranged along the conveying direction  60  fore and aft of the roller draw-forward unit  38 . The exit-side guide tube  41 , which is followed by the converter cutting device  10 , is arranged fixedly. The entry-side fiber guide tube  40  is arranged displaceably. 
     To thread a continuous fiber  11  into the fiber-draw-forward device  37 , the draw-forward roller  42  and the pressure roll  57  are moved apart from one another. The two fiber guide tubes  40 ,  41  of the compressed-air draw-forward unit  39  are subsequently pushed so near to one another that the continuous fiber, when introduced into the entry-side guide tube  40 , is automatically drawn into the exit-side guide tube  41  by the air stream. The guide tubes  40 ,  41  are in this case led through between the draw-forward roller  42  and the pressure roll  57 . 
     An air stream is subsequently generated in the guide tubes  40 ,  41 . By means of the air stream, the continuous fiber  11 , which has been introduced into the entry-side guide tube  40 , is automatically drawn through the fiber-draw-forward device  37  and, in particular, between the draw-forward roller  42  and the pressure roll  57 . 
     To fix the continuous fiber  11 , the fiber-draw-forward device comprises a fiber clamping unit  59 . The fiber clamping unit  59  is arranged in front of the entry-side fiber guide tube  40  with respect to the conveying direction  60 . As soon as the continuous fiber  11  passes completely through the fiber-draw-forward device  37 , the continuous fiber  11  is secured by means of the fiber clamping unit  59 . 
     The two guide tubes  40 ,  41  are subsequently pushed apart from one another and the pressure roll  57  is brought into contact with the draw-forward roller  42 . The continuous fiber  11  is thereby clamped between the draw-forward roller  42  and the pressure roll  57 . The fiber clamping unit  59  can be opened again. 
     During normal cutting operation, in which the converter cutting device  10  comminutes the continuous fibers into cut fibers, a conveying speed for the continuous fiber  11  is set by means of the roller draw-forward unit  38 . The conveying speed is in this case set via a rotational speed of the draw-forward roller  42 . The compressed-air draw-forward unit  39  is provided, during normal operation, for transporting the continuous fiber  11  through the guide tubes  40 ,  41  and further guide tubes, not illustrated in any more detail, which may be arranged fore or aft of the fiber-draw-forward device  37 .