Abstract:
An apparatus for depositing a filament tow in a stationary can. To this end, the filament tow is conveyed to the can by a conveyance means which includes a pair of driven reels. For deposition into the can, the filament tow is guided in such a way that the feed position of the filament tow in the can constantly changes. To allow the filament tow to be deposited with a high filling density, for deposition into the can the filament tow is guided by two separate oscillating motions of the conveyance means during conveying which are transverse to the conveyance direction. In this manner, undesired reactions on the filament tow are advantageously avoided during deposition.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   This is a DIV of U.S. application Ser. No. 10/453,197, filed Jun. 3, 2003, now U.S. Pat. No. 7,107,740, which is incorporated herein by reference. 

   FIELD OF THE INVENTION 
   The invention relates to an apparatus for depositing an advancing filament tow in which the filament tow is conveyed into a stationary can by a conveyance means, and while continuously changing the feed position of the tow into the can. 
   BACKGROUND OF THE INVENTION 
   A generic method and a generic apparatus for depositing filament tow in a can is known from European Patent Application 101 35 92 A1, for example. 
   In the melt spinning of individual or multiple fiber bundles, the fiber bundles are deposited in the form of a filament tow in a can for intermediate storage so that the filament tow may be supplied for further processing. It is necessary that a relative motion be carried out between the filament tow supply and the can in order to maintain uniform filling of the can. To this end, there are basically two different variants known from the prior art. In a first variant, the can is moved relative to the feed position using a cross-winding device. Such methods and devices which are known from European Patent Application 0 875 477 A2, for example, have the disadvantage that the can to be filled must be moved, which requires a considerable expenditure of energy, particularly at the end of filling, and correspondingly large drive designs. 
   In a second variant the can is stationary during filling. When being fed into the can the filament tow is moved by additional means in the form of a rotating plate. This variant is known from European Patent Application 101 35 92 A1, on which the present invention is based. 
   In the known method and the known apparatus, the filament tow is rotatably moved by means of a rotatably driven rotating plate. The rotating plate is eccentrically secured in a rotatable bearing plate, which is superimposed on the motion of the rotating plate. A conveyance means is situated upstream from the rotating plate, which continuously guides the filament tow to the rotating plate. Positioned on the rotating plate is a guide tube in which the filament tow is guided. 
   The known method and the known apparatus have the significant disadvantage that when the filament tow is deposited, twisting is created in the filament tow on account of the rotational motion of the rotating plate and the bearing plate, which has a particularly disadvantageous effect for thick filament tows when they are subsequently withdrawn from the can. Furthermore, as the result of additional guiding means the conveyance of the filament tow into the can is hindered by additional turns, so that only low filling densities can be achieved inside the can when the filament tow is being deposited. 
   It is the object of the present invention to provide an improved apparatus of the aforementioned type wherein the filament tow is conveyed, without twisting, into a stationary can in a straight course and wherein the tow may be deposited with a uniform filling density into the can. 
   SUMMARY OF THE INVENTION 
   The above and other objects and advantages of the present invention are achieved by the provision of an apparatus for depositing a filament tow in which the filament tow is conveyed into a stationary can by a conveyance means, and for deposition into the can the filament tow is guided in such a way that the feed position of the filament tow constantly changes in the can. The conveyance means comprises a pair of driven reels which cooperate with one another for conveying the tow into the can in a conveyance direction, and the conveyance means is mounted to a first member which is mounted to a second member so as to permit a first oscillating motion of the first member and the conveyance means in a direction which is transverse to the conveyance direction. The second member is mounted so as to permit a second oscillating motion of the second member in a direction which is transverse to the conveyance direction and transverse to the first oscillating motion. A first drive is provided for imparting the first oscillating motion and a second drive is provide for imparting the second oscillating motion. 
   Preferably, the first and second drives are independently controllable. Also, in one embodiment, the first member comprises a rocker which is pivotally connected to the second member for pivotal movement about a first generally horizontal axis so as to provide the first oscillating motion, and the second member comprises a second rocker which is pivotally connected to the holder for pivotal movement about a second generally horizontal axis which is substantially perpendicular to the first horizontal axis and so as to provide the second oscillating motion. In another embodiment, the second member comprises a carriage which is mounted to the holder for linear back and forth movement so as to provide the second oscillating motion. 
   In still another embodiment, the first member is pivotally mounted to a holder and the holder is mounted to the second member, with the second member being pivotally mounted to the machine frame so as to provide the second oscillating motion. The holder is displaceable along a linear guide on the second rocker for back and forth movement between at least two depositing positions. 
   The invention has the particular advantage that the filament tow is conveyed directly into the can and deposited without additional guiding means. To this end, the oscillating motions of the conveyance means achieve the motion of the filament tow for deposition in the can during conveying. As a result, the conveyance direction constantly changes so that the feed position of the filament tow into the can is specified by the conveyance direction. Two particular advantages in the deposition of the filament tow are thus realized. The first is that the energy introduced to the filament tow via the conveyance means can be used without restriction for creating a high filling density. The second is that, on account of the oscillating motions, the running characteristics of the filament tow are not changed. The filament tow is guided directly by the conveyance means for deposition, thereby avoiding undesired overlay effects in the filament tow. The filament tow is deposited in the can completely free of twists. 
   To obtain uniform two superimposed oscillating motions of the conveyance means guide filling of the can, in a first advantageous refinement of the invention the filament tow. The directions of the two motions are aligned transversely with respect to one another, thus enabling every region in the can to be filled uniformly. 
   The motions may basically be performed by an oscillating pivot of the conveyance means and/or by an oscillating linear motion of the conveyance means. In this way, the conveyance means may be advantageously designed using two superimposed pivot motions, or by two superimposed linear motions, or by a pivot motion and a superimposed linear motion. 
   The motions of the conveyance means are performed simultaneously, preferably at different speeds. Thus, for depositing the filament tow a motion of the conveyance means corresponding to a transverse motion is preferably performed quickly so that the filament tow is laid back and forth in a longitudinal direction to fill the can. In contrast, the second motion is performed slowly so that the layers of filament tow lie close to one another inside the can. 
   According to one particularly advantageous method variant, the speeds of motion of the conveyance means are changed and set independently of one another to enable adjustments to the geometry of the can and to the condition and size of the filament tow to be made. It is also possible to change the deflection path taken during the motion. 
   For carrying out the method, an apparatus according to the invention is provided in which the movable support which bears the conveyance means is associated with at least one drive, so that during conveying the conveyance means is continuously guided in oscillating motions transverse to the conveyance direction. Thus, the conveyance direction constantly changes during conveying of the filament tow, so that the filament tow occupies a continually changing feed position in the can. The particular advantage of the apparatus according to the invention is that the filament tow is conveyed and guided into the stationary can solely by the conveyance means. 
   A particularly simple and effective possibility for uniformly depositing the filament tow over the entire cross section of a can may be realized by the advantageous refinement of the apparatus according to the invention, in which two movable supports are associated with the conveyance means. Each of the movable supports is driven by respective independently controllable drives to perform an oscillating motion, the directions of motion of the supports being aligned transversely with respect to one another. 
   To enable the actual function of the conveyance means to be carried out essentially without limitation, in a particularly preferred embodiment, the support is formed by a rocker, which bears the conveyance means. The rocker is associated with a drive to achieve, for example, a more rapid pivot motion for depositing the filament tow. 
   The superimposed second motion of the conveyance means may be accomplished by placing the rocker bearing on a second rocker or securing it to a carriage. In this manner, an associated drive causes the second rocker or the carriage to perform a slow motion in a superimposed manner for guiding the first rocker, and thus for guiding the conveyance means. 
   To enable the cans to be exchanged as rapidly as possible after a can is filled, a holder is provided which secures at least the conveyance means and a support and which can be guided between multiple depositing positions. After filling, the conveyance means may thus be quickly guided to another depositing position using an empty can. 
   For uniform and intensive conveying of the filament tow, the conveyance means is preferably formed by two driven reels. The reels are driven independently of the changes in position of the reels, which are initiated by the supports. 
   The method according to the invention and the apparatus according to the invention are particularly suited for depositing thick filament tows having fiber bundles with large spinning titers of &gt;12,000 dtex, for example, which in particular are used for further processing of staple fibers. To this end, the apparatus according to the invention is situated downstream from a spinning device, which spins one, or more fiber bundles from a polymer melt. 

   
     BRIEF DESCRIPTION OF THE FIGURES 
     The apparatus according to the invention is described in greater detail below, using several exemplary embodiments with reference to the attached figures. 
       FIG. 1  schematically shows a first exemplary embodiment of the apparatus according to the invention, with a spinning device situated upstream. 
       FIG. 2.1  schematically shows an undeflected position of the conveyance means of  FIG. 1 . 
       FIG. 2.2  schematically shows a deflected position of the conveyance means of  FIG. 1 . 
       FIG. 3  schematically shows a cross-sectional view of the undeflected position shown in  FIG. 2.1 . 
       FIG. 4.1  shows a depositing apparatus schematically illustrated in a cross-sectional view. 
       FIG. 4.2  shows a top view of the apparatus. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1  schematically shows a first exemplary embodiment of the apparatus according to the invention for carrying out the method according to the invention, with a spinning device situated upstream. The apparatus according to the invention is denoted by reference number  3  in  FIG. 1 , and is referred to hereinafter as the depositing device. A spinning device  1  and take-off unit  2  are situated upstream from depositing device  3 . Depositing device  3  comprises a conveyance means  11  and a can  4 . 
   Spinning device  1  has a spinneret  6 , which extrudes a fiber bundle  7 . Spinneret  6  may have more than 80,000 nozzle holes. Spinning device  1  typically has cooling devices underneath the spinneret, which produce a cold air stream for cooling the fiber bundle. The cooling device is not illustrated in this example. The number of spinnerets in spinning device  1  is also by way of example. Thus, two, three, four, five, or even more spinnerets may be configured in parallel, each extruding a fiber bundle. To combine fiber bundles  7  to obtain filament tow  15 , multiple preparation devices  8  may be positioned between spinning device  1  and take-off unit  2 . A preparation agent is applied to the fiber bundle and filament tow  15 . When multiple spinnerets are used, all the fiber bundles may be combined into a filament tow by means of the preparation device or preparation rollers. 
   The take-off unit contains multiple take-off rollers  9  which are partially wrapped by filament tow  15 . Filament tow  15  is drawn from spinneret  6  by take-off rollers  9  and is guided to depositing device  3 . 
   Depositing device  3  has conveyance means  11  formed from two reels  13 . 1  and  13 . 2 , which are cooperatively driven. Conveyance means  11  is guided above can  4  in a holder  5 . 
   To explain depositing device  3 , in addition to  FIG. 1 , reference is also made to  FIGS. 2.1  and  2 . 2 , which in addition to the front view schematically illustrated in  FIG. 1  provides a side view of depositing device  3  without a can. The depositing device is shown in  FIG. 2.1  in an undeflected position for conveyance means  11 , and in  FIG. 2.2  in a deflected position for conveyance means  11 . The following description applies to both  FIG. 1  and  FIGS. 2.1  and  2 . 2  unless express reference is made to one of the figures. 
   Conveyance means  11  is secured on a first member or rocker  12 . Rocker  12  is rotatably supported on a second member or rocker  14  via a pivot axis  16 . First rocker  12  is associated with a first drive  17  by which first rocker  12  is driven in an oscillating manner, so that conveyance means  11  undergoes a pivotal motion, as shown by a dashed line in  FIG. 1 . 
   Second rocker  14  bears a feed roller  10  above first rocker  12  by which the supplied filament tow  15  is turned and guided to conveyance means  11 . Second rocker  14  is pivotally secured to a bearing journal  18  situated on holder  5 . Second rocker  14  is associated with a second drive  19  by which second rocker  14  is guided in a direction of motion that is transverse to the pivotal direction of first rocker  12 . A control device  20  connects drives  17  and  19 . 
   Holder  5  is configured to be displaceable in order to alternate between two depositing positions for filament tow  15 . The second depositing position for filament tow  15  is illustrated by dashed lines in  FIG. 1 . 
   In the arrangement shown in  FIG. 1 , a filament tow  15  is provided via spinning device  1  and take-off unit  2  for depositing into a can. Filament tow  15  is conveyed by the conveyance means in the direction of provided can  4 . To achieve uniform filling of can  4 , first drive  17  of first rocker  12  is actuated by control device  20  in such a way that a continuously oscillating pivotal motion is initiated at the first rocker, so that conveyance means  11  is guided back and forth in a first direction of motion. This changes the conveyance direction of filament tow  15 , which is denoted by the dashed arrows in  FIG. 1 . 
   To achieve a transverse direction of deflection for conveyance means  11 , the position of first rocker  12  is changed by means of second rocker  14 .  FIGS. 2.1  and  2 . 2  illustrate the situation in which second rocker  14  is pivoted by second drive  19 . The pivotal motion of second rocker  14  is performed in an oscillating manner at a lower speed to achieve uniform filling of can  4 . 
   Filament tow  15  is continuously conveyed into can  4  in each deflected position of conveyance means  11 . Thus, each of the feed positions inside can  4  is specified by the constantly changing conveyance direction. Filament tow  15  thus exits, without additional turns, from conveyance means  11  directly into can  4 . The pivotal motion of first rocker  12  and the pivotal motion of second rocker  14  are independently adjustable via drives  17  and  19  and control device  20 . The pivotal motions of rockers  12  and  14  are preferably carried out at different speeds. The pivot angle through which rockers  12  and  14  pass during the motions is such that filament tow  15  can be deposited in any region of can  4 . The pivot angle of rockers  12  and  14  can be adjusted depending on the size of can  4 . 
   In the situation illustrated in  FIG. 1 , the depositing positions are changed as soon as can  4  is filled with filament tow  15 . To this end, holder  5  is guided into a second adjoining depositing position and fixed in place. The filament tow is cut using auxiliary devices and placed in new empty can  4 . 
   The full can may thus be easily replaced by a new empty can. 
   A further exemplary embodiment of a device according to the invention is schematically illustrated in a cross-sectional view in  FIG. 3 . The exemplary embodiment in  FIG. 3  shows the depositing device, in which conveyance means  11  is guided to holder  5 , and can  4  is situated underneath conveyance means  11 . The function and structure of the depositing device are essentially identical to those of the preceding exemplary embodiment, so that only the differences will be pointed out here. 
   Here as well, conveyance means  11  is formed by two reels, which are pivotally secured to rocker  12 . Rocker  12  is secured to a carriage  21  via pivot axis  16 . Carriage  21  is guided to holder  5  by means of a linear guide  22 . Carriage  21  is associated with linear drive  23  by which the position of carriage  21  may be changed. Linear drive  23  and drive  17  of rocker  12  are coupled to control device  20 . 
   To guide filament tow  15  during conveying by conveyance means  11 , conveyance means  11  is moved by rocker  12  in a pivotal direction transverse to the plane of the drawing, and is moved by carriage  21  and linear drive  23  in a direction of motion within the plane of the drawing. To this end, carriage  21  is moved in an oscillating manner by linear drive  23 , the linear motion-taking place at a slower speed than the pivotal motion of rocker  12 . The lift of carriage  21  is determined by linear drive  23 , it being possible to change the lift by controlling linear drive  23 . 
   A further exemplary embodiment of an apparatus according to the invention is schematically illustrated in several views in  FIGS. 4.1  and  4 . 2 . The exemplary embodiment in  FIG. 4  shows only the depositing device, upstream from which a take-off unit and a spinning device are situated. The spinning device and the take-off unit could be designed, for example, as previously described in the exemplary embodiment according to  FIG. 1 . The depositing device is schematically illustrated in a cross-sectional view in  FIG. 4.1 , and is schematically illustrated in a top view in  FIG. 4.2 . For the sake of clarity, components having the same function are provided with the same reference numbers. 
   Conveyance means  11 , which is formed by two reels  13 . 1  and  13 . 2  and a roller support  25 , is borne by a first member or rocker  12 . Rocker  12  is fixedly joined to roller support  25 . Rocker  12  is supported on two ends on a holder  5  via pivot axes  16 . 1  and  16 . 2 , which are situated opposite one another. Rocker  12  and holder  5  are each designed as a rectangular frame section, the frame section of holder  5  enclosing rocker  12  at a distance. Rocker  12  is pivotally secured to holder  5  via pivot axes  16 . 1  and  16 . 2 . The pivotal motion of rocker  12  is controlled by a drive  17 , which is coupled to swivel axis  16 . 1 . 
   Holder  5  is guided in a linear guide  22  to a second member or rocker  14 . Second rocker  14  is likewise formed by a rectangular frame section, on the long inner side of which linear guide  22  for holder  5  is provided. Holder  5  may thus move back and forth between multiple depositing positions  24  on rocker  14 . Rocker  14  is pivotally supported on two ends on a machine frame member  26  by means of bearing journals  18 . 1  and  18 . 2 . The pivotal motion of rocker  14  is controlled by drive  19 , which is coupled to bearing journal  18 . 2 . 
   In the exemplary embodiment of the depositing apparatus shown in  FIG. 4 , holder  5  is secured in a left-hand depositing location  24  of a rocker  14 . When a filament tow is being deposited, holder  5  is locked in place on rocker  14 . Reels  13 . 1  and  13 . 2  of conveyance means  11  are continuously driven when a filament tow is being deposited, so that the filament tow is fed in the direction of a can  4  secured in a depositing location  24 . To fill can  4 , rocker  12  is moved in an oscillating manner by drive  17  in such a way that the conveyance direction of conveyance means  11  constantly varies. The second motion of conveyance means  11  is performed by rocker  14  via drive  19 . The pivotal motion of rocker  14  is slower compared to the pivotal motion of rocker  12 , and serves the sole purpose of allowing the filament tow to be uniformly distributed over the entire cross section of can  4 . 
   Electrical, electromechanical, pneumatic, or hydraulic means may be used as drives  17  and  19 . 
   As soon as can  4  is filled, the motion of rocker  14  is stopped and holder  5  is released. Holder  5  is then guided to adjoining depositing location  24  and locked in place once again. At this time a new can may be filled with the filament tow. 
   The exemplary embodiments shown in  FIGS. 1 through 4  are exemplary in design. In principle, all suitable apparatus for performing a motion of the conveyance means may be used to guide the filament tow during conveying in such a way that a subsequent can is uniformly filled with a high filling density. In this respect, the invention extends to all apparatus in which a stationary can is used and in which the filament tow or a similar strand-shaped material is guided solely by motion of the conveyance means.