Abstract:
In an arrangement for mixing fiber components, for example fiber flocks, especially in spinning preparation, fiber web production or the like, in which the fiber material to be supplied is conveyable into at least two weighing containers and, when weighing is complete, the fiber material is dischargeable from the at least two weighing containers onto a mixing belt, the weighing containers are arranged one after the other—seen in the direction of travel of the belt—above the mixing belt. In order that accurate weighing, troublefree production and increased throughput can be achieved in a simple manner, the position of at least one weighing container can be adjusted transverse to the longitudinal extent of the mixing belt.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
   This application claims priority from German Patent Application No. 10 2004 048 222.5 dated Sep. 30, 2004, the entire disclosure of which is incorporated herein by reference. 
   BACKGROUND OF THE INVENTION 
   The invention relates to an arrangement for mixing fibre components, for example fibre flocks, especially in spinning preparation, fibre web production or the like. 
   Flock-mixing systems are used for the production of accurate and intensive mixing for spinning and the non-woven industry. The materials mixed are: different synthetic fibres, cotton and synthetic fibres, different recovered waste fibres, cotton and recovered waste fibres. For the spinning of blend yarns of synthetic fibres and carded cotton, in modern spinning works the components are generally mixed in flocks on flock-mixing systems. Such a process results in more intensive mixing. 
   In a known method, the fibre material to be supplied is conveyable into at least two weighing containers and, when weighing is complete, the fibre material is dischargeable from the at least two weighing containers onto a mixing belt, the weighing containers being arranged one after the other—seen in the direction of travel of the belt—above the mixing belt. 
   In high-production weighing hopper-feeders, in practice the weighing container, which is generally arranged centrally above the mixing belt, forms a cone of material which, when several machines are arranged one after the other, very quickly results in large accumulations of fibre. At the same time, disadvantageously, there may occur defective weighings caused by incompletely emptied weighing containers and material densities that are too high in the centre, resulting in disruptions in the transport of the material and in the opening at the downstream mixer rollers. 
   It is an aim of the invention to provide an arrangement of the kind described at the beginning which avoids or mitigates the mentioned disadvantages and which makes it possible in a simple way to achieve accurate weighing, troublefree production and increased throughput. 
   SUMMARY OF THE INVENTION 
   The invention provides a fibre mixing system comprising:
         a travelling mixing belt; and   at least two weighing containers, arranged one after the other in a direction of travel of the belt, for delivering weighed fibre material onto the belt;
 
wherein the position of at least one of said weighing containers in a transverse direction relative to the direction of travel of the belt can be adjusted.
       

   The measures taken according to the invention can bring about more uniform deposition or arrangement of the fibre material on the mixing belt. The distribution of the fibre material on the mixing belt can thereby be optimised and the throughput of the weighing hopper-feeder system can be substantially increased. 
   Advantageously, the position of at least one weighing container can be adjusted in the direction of the transverse extent of the mixing belt. Advantageously, the position of each weighing container can be adjusted. Advantageously, the position of the weighing container(s) can be adjusted in dependence upon one or more parameters selected from the group consisting of the mixing ratio of the fibre contents; the proportions of the fibre components; the mass of the fibre components; and the number of weighing containers. 
   Advantageously, the at least two weighing containers are movable relative to the mixing belt. Advantageously, the mixing belt is in a fixed position. Advantageously, the at least two weighing containers can be moved, preferably linearly, back and forth above the mixing belt. Advantageously, the at least two weighing containers are displaceable parallel to the mixing belt. Advantageously, for displacing each of the at least two weighing containers, each weighing container is associated with at least one linear drive and/or at least one parallel guide. Where present, the parallel guide may have two guide means (linear guides) coupled to one another to run synchronously. Advantageously, the guide means are associated with side walls of the weighing container that are located opposite one another. Advantageously, the guide means are coupled to one another by a synchronisation shaft. Advantageously, the guide means comprise at least one spindle drive. Advantageously, the guide means comprise at least one pressure cylinder. The pressure cylinder may be, for example, a pneumatic cylinder or a hydraulic cylinder. Advantageously, the pressure cylinder is a three-position cylinder. The guide means may each have a traction mechanism, for example, a chain or a toothed belt, which advantageously circulates around two guide rollers, wheels (for example, sprocket or toothed belt wheels) or the like. 
   Advantageously, the displacing device is associated with at least one drive device. A manual drive device, for example, a crank wheel or the like, may be present. Advantageously, at least one motor drive device, for example, an electric motor, is present. The drive device may be, for example, a geared motor or a stepping motor. Advantageously, stepless adjustment of the position of the weighing container(s) is provided. Advantageously, actual value feedback from the at least one drive device is provided. The actual value feedback may be a cam plate or the like having an inductive proximity switch. Advantageously, the at least one drive device is connected to an electronic controlling and regulating device, for example, a microcomputer. Advantageously, each weighing device is associated with a position-measuring element (actual value), which is preferably connected to the controlling and regulating device. Advantageously, a desired value memory is connected to the controlling and regulating device. Advantageously, the proportion by weight of each fibre component can be input into the controlling and regulating device. Advantageously, the controlling and regulating device is able to calculate the position of the weighing containers from the proportions by weight of the fibre components and the number of weighing devices. Advantageously, the controlling and regulating device is able to output electrical signals to the drive devices, for example, electric motors, for setting the position of the weighing container(s). 
   Advantageously, each weighing container is associated with at least one weighing cell or the like, and the weighing container can be displaced together with the at least one weighing cell or the like. Advantageously, on altering the mixing ratio of the fibre components, the position of the weighing containers can be adjusted. Advantageously, a selectable off-centre position of the at least one weighing container is provided. Advantageously, the mixing belt is associated with at least two weighing bale openers. Advantageously, the mixing belt is associated with at least two pneumatically fed weighing feeders. 
   The invention also provides an arrangement for mixing fibre components, for example, fibre flocks, especially in spinning preparation, fibre web production or the like, in which the fibre material to be supplied is conveyable into at least two weighing containers and, when weighing is complete, the fibre material is dischargeable from the at least two weighing containers onto a mixing belt, the weighing containers being arranged one after the other—seen in the direction of travel of the belt—above the mixing belt, characterised in that the position of at least one weighing container transverse to the longitudinal extent of the mixing belt can be adjusted. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a diagrammatic view of a fibre-mixing system having four weighing feeders, a mixing belt and an opener roller, 
       FIG. 2  is a side view of a weighing bale opener with a weighing container above the mixing belt, 
       FIG. 3   a  shows the weighing container in a first position above the mixing belt, 
       FIG. 3   b  shows the weighing container in a second position above the mixing belt, 
       FIG. 4  is a side view in section I-I according to  FIG. 1  with two weighing containers in different positions, 
       FIG. 5  shows a first embodiment of the displacement device for the weighing container having a mechanical displacing device, 
       FIG. 6  shows a second embodiment of the displacement device for the weighing container having a pneumatic displacing device, 
       FIG. 7  shows a third embodiment of the displacement device for the weighing container having an electromotive displacing device, and 
       FIG. 8  is a block circuit diagram of an electrical controlling and regulating device having three connected controllable electromotive displacing devices for displacement of the associated weighing devices. 
   

   DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
   With reference to  FIG. 1 , a flock-mixing system  1  according to  FIG. 1  consists of a flock mixer  2  having a high-speed opener roller  3  and a mixing table  4 . The mixing table  4  is located below the weighing bale openers  5   a ,  5   b ,  5   c ,  5   d , and the flock mixer  2  is located at the end of the mixing table  4 . The weighing bale openers  5   a ,  5   b ,  5   c ,  5   d  each include a respective weighing container  7   a ,  7   b ,  7   c ,  7   d . Between the discharges  6   a ,  6   b ,  6   c ,  6   d  (fibre components) of the weighing containers  7   a ,  7   b ,  7   c ,  7   d , the conveyor belt  8  of the mixing table  4  continues in the direction of the opener  2  only by the width of a weighing container  7   a  to  7   d . As a result, the individual discharges  6   a  to  6   d  of each weighing container  7   a  to  7   d  produce unbroken layers of fibre material  9   a ,  9   b ,  9   c ,  9   d  lying one on top of the other. The conveyor belt  8  conveys the superposed fibre layers  9   a  to  9   d  of the mixture components to the flock mixer  2  (opener). Material is discharged from each of the weighing containers  7   a  to  7   d  in such a manner that the components to be mixed are layered one above the other and are at the same time conveyed to the intake into the mixing opener  2 . First, the weighing feeder  5   a  discharges its fibre component portion onto the mixing belt  8 , which transports that layer  9   a  to weighing feeder  5   b , where the next component is deposited from weighing container  7   b  onto the layer  9   a  from weighing feeder  5   a  and the two layers are transported further to weighing feeder  5   c  which then deposits the third component  6   c  onto the two layers  9   a  and  9   b . Finally, from the weighing container  7   d  of weighing feeder  5   d , the fibre material component  6   d  is deposited onto the layers already present. All four layers  9   a  to  9   d  pass underneath a pressing roller at the end of the conveyor belt  8  and are supplied by two slow-speed feed rollers to the mixing opener  2  which continuously mixes the stack of layers and passes it on to a further processing machine through pipeline  10 . Reference letter a denotes the longitudinal extent (lengthwise alignment) of the mixing belt  8 . Reference letter A denotes the operating direction which corresponds to the direction of travel of the upper belt portion  8   a  of the conveyor belt  8 . 
   The weighing bale opener according to  FIG. 2  has a support table  11  for fibre bales or the like and a feed table  12  which conveys the fibre material F to the obliquely ascending needle table  13  which carries the fibre material upwards. The evening roller  14  throws excess flocks onto the material F, which has collected on the feed table  12 , the component being mixed into itself. The high-speed stripper roller  15  combs the flocks from the needle table  13  and throws them into the pre-filling chamber  16  from which they fall into the weighing container  7 . The pre-filling chamber  16  is closable at its lower end by two pivotally mounted closing flaps  17   a ,  17   b  (in  FIG. 2  the closing flaps  17   a ,  17   b  are shown in their open position). The weighing container  7  is closable at its lower end by two pivotally mounted base flaps  18   a ,  18   b  (in  FIG. 2  the base flaps  18   a ,  18   b  are shown in the open position). The mixing belt  8  passes below the weighing container  7 , the fibres weighed out in the weighing container  7  being discharged onto the upper belt portion  8   a  of the mixing belt  8 . The weighing container  7  can be displaced in the direction of arrows B and C. Reference letter b denotes the transverse extent (transverse direction) of the mixing belt  8 . 
   In  FIGS. 3   a  and  3   b  the weighing container  7   c  is shown in two positions  7   c ′ and  7   c ″ above the mixing belt  8 , which positions are assumed one after the other. Reference numeral  19  denotes a centre line in respect of the width b of the conveyor belt  8 . According to  FIG. 3   a , at timepoint t 1  the centre of the weighing container  7   c ′ is located at distance x 1  from the centre line  19 , and according to  FIG. 3   b  at timepoint t 2  the centre of weighing container  7   c ″ is located at distance x 2  from the centre line  19 . In this way the material cone of the weighing container  7   c  is located to the right, according to  FIG. 3   a , and to the left, according to  FIG. 3   b , of the centre line  19 . The respective other material cone originates from another weighing container, for example weighing container  7   b . Reference numerals  20   a ,  20   b  denote side walls, and reference numeral  21  denotes the discharged fibre material. 
   In  FIG. 4  the weighing containers  7   b  and  7   c  are each shown in a specific position above the mixing belt  8  at the same timepoint t o . The centre of the weighing container  7   b  is located at distance y 1  from the centre line  19 , and the centre of the weighing container  7   c  is located at distance Y 2  from the centre line  19 . In this way, the material cones of the weighing containers  7   b  and  7   c  are located on different sides of the centre line  19 . 
   An important point lies in the position of the weighing containers  7  being adjustable in dependence on the mixing ratios (e.g. 50:25:25). For example, for a desired mass ratio 50%:25%:25% of three different fibre material components, weighing container  7   a  could be positioned at distance y 1  (25%), weighing container  7   b  at distance y 1  (25%) and weighing container  7   c  (50%) at distance y 2  from the centre line  19 . 
   In accordance with  FIG. 5 , a mechanical displacement device  39  is provided for the weighing container  7  with the weighing cell  22  (measuring cell for weight registration). Above the weighing container  7  there are mounted on the machine frame  23  two holding elements  24   a ,  24   b  which carry a threaded spindle  25  having a rotatable hand wheel  26 . Two threaded nuts  27   a ,  27   b  cooperate with the threaded spindle  25  and are rigidly coupled to one another by means of a connecting bar  28 . The weighing cell  22 , from which the weighing container  7  is suspended by means of a holding member  29 , is mounted on the connecting bar  28 . When the hand wheel  26  is rotated, the weighing container  7  is shifted in direction B or C. 
   According to  FIG. 6 , there is a pneumatic displacement device  40  for the weighing container  7  with the weighing cell  22 . The holding elements  24   a ,  24   b  carry a straight rod  30 , on which two sliding sleeves  31   a ,  31   b  slide, which sliding sleeves are rigidly coupled to one another by means of the connecting bar  28 . The end of the piston rod  32   a  of a pneumatic cylinder  32  is articulated on the sliding sleeve  31   b . A three-position cylinder is used which can travel to the left-hand end position, the centre position and the right-hand end position. The rod  30 , the sliding sleeves  31   a ,  31   b  and the connecting bar  28  form a linear guide. On displacement of the piston  32   b  with the piston rod  32   a , the weighing container  7  with the weighing cell  22  is shifted in direction B or C. 
     FIG. 7  shows stepless adjustment using a motor drive means. An actual value feedback from the electric drive motor  32  is provided (see  FIG. 8 ) so that the weighing containers can be moved to exactly preselected positions by way of the system control means (see  FIG. 8 ). The drive motor  32  can be, for example, a geared motor. The linear guide corresponds to that according to  FIG. 7 , to which reference is made. The two open ends of a toothed belt  33  are attached to the sliding sleeves  31   a ,  31   b , which toothed belt circulates around two toothed belt wheels  34   a ,  34   b . The toothed belt wheel  34   b  and a further toothed belt wheel  36  (not shown) are attached to a common shaft  35   b . A continuous toothed belt  37  circulates around the toothed belt wheel  36  and the drive shaft  38  of the drive motor  32 . On rotation of the drive shaft  38 , the weighing container  7  with the weighing cell  22  is shifted in direction B or C. Reference numeral  41  denotes the electromotive displacement device. 
   In accordance with  FIG. 8 , the positions of the weighing containers  7   a ,  7   b  and  7   c , each with weighing cells, can be adjusted automatically. From the specified proportions by weight of the different fibre material components a control means effects optimum distribution of fibre material on the mixing belt  8  in dependence upon the preselected proportions by weight. Above the mixing belt  8 , three weighing containers  7   a ,  7   b  and  7   c  are mounted, one after another in the operating direction A, on electromotive displacement devices  41 ′,  41 ″ and  41 ′″ (see  FIG. 7 ). The drive motors  32 ′,  32 ″ and  32 ′″ are connected by electrical lines to an electronic controlling and regulating device  42 , for example a microcomputer. By way of lines  43 ′,  43 ″,  43 ′″, the electrical control signals for the drive motors  32 ′,  32 ″ and  32 ′″, respectively, are transmitted in accordance with a specified desired value. By way of lines  44 ′,  44 ″ and  44 ′″, the electrical signals for the actual value (positions) are transmitted (fed back) from the drive motors  32 ′,  32 ′″and  32 ′″, respectively. The proportions by weight of the individual fibre material components are specified by means of an input device  45 , for example a keyboard or the like. Reference numeral  46  denotes a memory unit into which the positions of the weighing containers  7   a ,  7   b ,  7   c  for a certain mixing ratio can be input and stored, so that when the same mixture is being processed the setting can be called up from the memory  46  and implemented. 
   Although the foregoing invention has been described in detail by way of illustration and example for purposes of understanding, it will be obvious that changes and modifications may be practised within the scope of the appended claims.