Patent Publication Number: US-2022212368-A1

Title: Apparatus for Cross-Sectionally Shaping a Multiplicity of Plastics Fibre Bundles Guided in Parallel

Description:
The invention relates to a device for cross-sectional shaping of a plurality of plastics fiber bundles guided in parallel alongside one another via at least one rotatable shaping roller. 
     Lightweight components made of plastics material, such as are often used in the automotive industry or in aircraft construction, generally contain fiber materials made of glass or carbon in order to save weight while simultaneously having a high strength. The fiber materials are generally incorporated into the polymer melt of a plastics material by means of an impregnating device and then processed as a plastics fiber bundle into pellets, granules or ribbons having a defined cross-section which are used in subsequent facilities and methods, in particular injection molding methods, for producing the lightweight construction elements. 
     In the simplest case, the cross-sectional shaping or calibration of the impregnated fiber bundles can take place via a nozzle having a defined diameter. However, a more precise cross-sectional shaping can only be achieved in a semi-solid but still heated state of the fiber bundle mixed with plastics material, so that for more precise calibration it is necessary to first cool the plastics fiber bundle in a water bath after exiting the nozzle and then reshape it in a still deformable state. 
     For this purpose, shaping rollers have become known which cool the still warm or hot plastics fiber bundles into surface depressions of a defined cross section, before the plastics fiber bundles are rolled up or fed to a granulator. 
     A shaping roller for cross-sectional shaping is usually immediately downstream of the water bath of an impregnation unit. However, since there may also be a need for impregnated fiber bundles of different cross sections, it is necessary to adapt the shaping roller to such different cross sections, which is generally achieved in that, in accordance with the new task, the shaping roller is replaced by a shaping roller having a correspondingly changed cross-sectional shape of the shaping depressions. The processes of changing a shaping roller and of cleaning can be complex and time-consuming, in particular if a plurality of shaping rollers are arranged one behind the other. 
     The object is therefore that of specifying a device for the cross-sectional shaping of a plurality of impregnated plastics fiber bundles guided in parallel, the shaping roller(s) of which improves the roundness of the plastics fiber bundles, the standstill time of which when changing one or more shaping rollers can be kept low, which is of compact construction, at the same time allows effective cooling of plastics fiber bundles and is adjustable to a large extent. 
     This object is achieved by the invention specified in claim  1 . Further embodiments of the invention are specified in the dependent claims. 
     In the invention, a shaping roller is used which is mounted in lateral guide plates by means of a quick-change device. The shaping roller has rotary couplings on the end face, via which liquid media, in particular for cooling, are guided through the shaping roller. After separation of the supply and discharge lines of the rotary couplings and removal of the quick-change device, the shaping roller can simply be removed from the frame. 
     Preferably, in the invention, three identical shaping rollers are used for the post-shaping of plastics fiber bundles, which rollers are arranged in a triangular manner and are each provided on their surface with a plurality of peripheral shaping depressions arranged in parallel, in which the cross section of supplied fiber bundles which are impregnated with plastics material can be shaped in accordance with the cross-sectional shape of the shaping depressions. 
     In this case, the fiber bundles are guided through between a pair of two successive shaping rollers on a first side of the fiber bundles, and a third shaping roller which is located on the second side of the plastics fiber bundles in the running direction of the plastics fiber bundles between the first and second shaping rollers of the pair of shaping rollers. The distance between the shaping rollers can be adjustable horizontally and/or vertically. The surface temperature of the shaping rollers is preferably controllable. 
     The number of shaping rollers and their arrangement relative to one another can also be selected differently if required. Thus, in the case of very high demands on the dimensional accuracy or in the case of special polymers, a greater number of shaping rollers acting on the fiber bundles, for example an arrangement having 2×3 shaping rollers, can be selected. 
     This embodiment of the invention permits an effective cross-sectional shaping of plastics fiber bundles during passage through the gap between the shaping rollers, while simultaneously cooling, so that the plastics fiber bundles leave the device having a defined cross-sectional shape. 
     The adjustment of the spacing of the shaping rollers in the horizontal and vertical position thereof makes it possible to control the tension of the plastics strands, their dwell time on the shaping rollers, and corresponding control of the cooling effect. 
     The shaping rollers are preferably arranged in such a way that a first and a second shaping roller are located in a horizontal plane below the plastics strands, and a third shaping roller is located above the plastics strands at a vertical distance from the first and second shaping rollers. In this case, the vertical position of the third shaping roller is preferably selected in such a way that this shaping roller presses the plastics fiber bundles between the first and second shaping rollers so as to thereby widen the wrap angle of the shaping rollers that is touched by the plastics strands, increase the pressing force of the plastics strands into the shaping depressions and thus improve the shaping quality. 
     The arrangement of the lower and the upper shaping rollers relative to one another can also be mirrored in the vertical. 
     The shaping rollers are preferably mounted on the end face in lateral guide plates of a frame, a first guide plate pair accommodating the first and second shaping roller, and a second guide plate pair carrying the third shaping roller. The guide plates can preferably be displaced vertically via bar guides, the displacement taking place synchronously in order to be able to carry out the displacement uniformly over the entire length of the shaping rollers. 
     Furthermore, it is also possible for the horizontal distance between the first and second shaping rollers to be adjustable. The vertical arrangement of the shaping rollers with respect to the upper or lower side of the plastics fiber bundles can also be inverted. 
     With the aid of the simplified device according to the invention, fiber bundles impregnated with plastics material, and pellets and granules produced therefrom, can be calibrated in such a way that their roundness is improved, that they are worked once again during shaping in order to improve their properties, that they have a better running quality in subsequent transport systems, and finally have a better appearance. 
    
    
     
       The invention is explained in more detail in the following, with reference to an embodiment. In the drawings: 
         FIG. 1  is an isometric view of a device for cross-sectional shaping of plastics strands according to the invention, 
         FIG. 2  is a longitudinal sectional view of a shaping roller, 
         FIG. 3  is an enlarged view of a quick-change device for a shaping roller, and 
         FIG. 4  is a front view of the quick-change device for a shaping roller. 
     
    
    
     The device shown in  FIG. 1  includes a frame  1  formed substantially of a pair of upper bridge supports  5  and a pair of lower bridge supports  4  which are interconnected by four vertical guide rods  7 ,  8 ,  9 . The frame  1  can be moved in a horizontal plane on a rail arrangement having two parallel rails  2  and  3 , by means of a hand wheel  6 . 
     A pair of upper guide plates  10 ,  12  and a pair of lower guide plates  11 ,  13  are arranged one above the other, on the guide rods  7 ,  8 ,  9 , so as to be vertically displaceable. The pair of guide plates  10 ,  12  can be raised or lowered via hydraulic lifting devices  14 ,  15 . Accordingly, the pair of lower guide plates  12 ,  14  can be raised or lowered via the lower lifting devices  16 ,  17 . 
     In order to ensure the synchronicity of the raising and lowering, the pairs of guide plates are assigned a pair of toothed wheels  21  which are interconnected via a connecting rod and engage in a pair of toothed racks  22  on both sides of the device and thus permit a parallel adjustment of the guide plates. 
     An upper shaping roller  18  is arranged between the pair of upper guide plates  10 ,  12 , the shaft of which upper shaping roller is mounted laterally in the guide plates  10 ,  12  so as to be freely rotatable. The pair of lower guide plates  11 ,  13  carries two lower shaping rollers  19 ,  20  arranged in parallel and spaced apart from one another, the three shaping rollers being arranged substantially in a triangular shape having a horizontal base, in which the lower shaping rollers  19 ,  20  lie, which are also freely rotatable. 
     In order to be conducted through the device according to the invention, the plastics fiber bundles (not shown in  FIG. 1 ) are guided in two groups, in parallel and side-by-side, through the gap between the first lower shaping roller  19  and the upper shaping roller  18 , and then through the gap between the upper shaping roller  18  and the second lower shaping roller  20 . The vertical distance between the upper shaping roller  18  and the lower shaping rollers  19 ,  20 , and the horizontal distance between the lower shaping rollers  19  and  20 , is set such that the plastics fiber bundles on the shaping rollers pass through a wrap angle of approximately 2-20°, preferably 5-6°, relative to the respective shaping roller. Thus, they penetrate with sufficient pressing force into the peripheral U-shaped depressions worked into the surface of the shaping rollers, so as to undergo a post-shaping of their cross section when passing through the device. The distance between the upper shaping roller  18  and the lower shaping rollers  19 ,  20  can be selected to be so small that upper and lower shaping rollers touch and can thus run synchronously, provided that the plastics fiber bundles do not protrude too far from the shaping depressions. In order to increase the wrap angle of the plastics fiber bundles during their passage between the shaping rollers, the distance between the lower shaping rollers can be increased, and at the same time the vertical distance between the upper shaping roller and the lower shaping roller can be reduced. 
     The shaping rollers  18 ,  19 ,  20  are fastened in the guide plates  10 - 13  on the front side by means of quick-change devices. They can therefore be easily removed from the device and exchanged for maintenance or replacement. 
       FIGS. 2 and 3  show the upper shaping roller  18  in a sectional side view. The lower shaping rollers  19  and  20  are designed so as to be substantially identical to the upper shaping roller. The shaping roller  18  is designed as a sleeve and carries on its outer side a plurality of peripheral shaping depressions arranged in parallel. The shaping roller  18  is mounted in the lateral guide plates  10 ,  12  via the quick-change devices  24 ,  35 . The shaft of the shaping roller  18  is designed as a displacement cylinder  26 , in particular made of plastics material, a free peripheral annular gap  29  extending between the inner wall of the shaping roller  18  and the displacement cylinder  26 , through which annular gap a liquid medium, in particular water, is passed for cooling the outer wall of the shaping roller  18 . 
     The cooling medium is supplied at one end face of the shaping roller via the connection  36  and the rotary coupling  34 , guided via the axial bore  30  and the distributor channel  27  to the annular gap  29 , then passes through the annular gap  29 , and is removed again at the other end face of the shaping roller. The cooling circuits of the three shaping rollers can be operated in parallel or in series. 
     The device according to the invention can also be operated not only for cooling the surface of the shaping rollers, but rather, in alternative applications, also for heating by means of heated water or, at required still higher temperatures, also using oil or correspondingly suitable alternative fluids. 
     The diameter of the upper and lower shaping rollers is preferably the same, but it can also be selected differently for certain cases. A diameter suitable for the purposes of the invention is approximately 150 mm. The rounding diameter in the shaping depressions is preferably 1.8 to 3.5 mm 
       FIG. 3  is a cross-sectional view of the quick-change device  35  used for the storage and supply and removal of cooling medium. The sleeve-like shaping roller  18  is fastened at the end face in a bearing housing  33  which is rotatably mounted on a hollow shaft  37  via bearings  31 ,  32 . The hollow shaft  37  is received at the end side in a hollow shaft receptacle  23 , which is inserted into the guide plates  10 ,  12  as a part of the quick-change device  24 ,  35 . 
     The hollow shaft  37  is provided with a hydraulic rotary coupling  34 , via which the shaping roller  18  is supplied with cooling medium, which is transferred from the rotary coupling  34  via the axial bore  30  of the hollow shaft  37  and the distributor channels  27  into the annular gap  29  and, conversely, is removed again at the other end face of the shaping roller. Since the hollow shaft  37  and the displacement cylinder  26  are not rotatable, a seal  38  is provided between the rotating bearing housing  33  and the non-rotating hollow shaft  30 . 
       FIG. 4  shows the end face of a quick-change device. Two pivot levers  25 ,  28  are provided for fastening the shaping roller in the guide plates. In order to release a shaping roller, a hose is first to be uncoupled from the central connection  36  and the rotary coupling  34 . The two pivot levers  25 ,  28  must then be released and pivoted about 90°, so that the hollow shaft receptacle can be removed axially from the guide plate, at the side, and the hollow shaft  37  then rests only on a carrier strip  39  which is fastened to the guide plate  10 . The hollow shaft can now be removed upwards or to the side. The hollow shaft is inserted in the reverse manner. The convex shape of the carrier strip  29  and of the carrier part  40  of the hollow shaft receptacle  23  extending through the guide plate secure the hollow shaft in the radial direction in the installed state. 
     The subject matter of the invention is of compact construction, can be easily serviced, and allows an effective post-shaping, having improved roundness of fiber bundles impregnated with plastics material, before further processing, in particular pelleting or granulation. 
     The device is preferably also completed with upper and lateral cover plates (not shown in the drawings). 
     REFERENCE SIGNS 
       
     
       
         
           
               
               
             
               
                   
               
             
            
               
                 1 
                 frame 
               
               
                 2 
                 rail 
               
               
                 3 
                 rail 
               
               
                 4 
                 lower bridge support 
               
               
                 5 
                 upper bridge support 
               
               
                 6 
                 hand wheel 
               
               
                 7 
                 guide rod 
               
               
                 8 
                 guide rod 
               
               
                 9 
                 guide rod 
               
               
                 10 
                 guide plate 
               
               
                 11 
                 guide plate 
               
               
                 12 
                 guide plate 
               
               
                 13 
                 guide plate 
               
               
                 14 
                 lifting device 
               
               
                 15 
                 lifting device 
               
               
                 16 
                 lifting device 
               
               
                 17 
                 lifting device 
               
               
                 18 
                 upper shaping roller 
               
               
                 19 
                 lower shaping roller 
               
               
                 20 
                 lower shaping roller 
               
               
                 21 
                 toothed wheel 
               
               
                 22 
                 toothed rod 
               
               
                 23 
                 hollow shaft receptacle 
               
               
                 24 
                 quick-change device 
               
               
                 25 
                 pivot lever 
               
               
                 26 
                 displacement cylinder 
               
               
                 27 
                 distributor channel 
               
               
                 28 
                 pivot lever 
               
               
                 29 
                 annular gap 
               
               
                 30 
                 axial bore 
               
               
                 31 
                 bearing 
               
               
                 32 
                 bearing 
               
               
                 33 
                 bearing housing 
               
               
                 34 
                 rotary coupling 
               
               
                 35 
                 quick-change device 
               
               
                 36 
                 connection 
               
               
                 37 
                 hollow shaft 
               
               
                 38 
                 seal 
               
               
                 39 
                 carrier strip 
               
               
                 40 
                 carrier part