Abstract:
In a continuous machine for filling containers with at least one powdered product, each container is fed along a path phased with a corresponding metering device, which transfers the product from a tank to the container, and has a cylinder and a piston axially movable under the bias of corresponding tappets engaged in corresponding cams; the cam of the piston having a horizontal segment, which keeps the piston on the upper surface of the product during the insertion of the cylinder into the product itself, and whose vertical position is selectively controlled according to a height of the product in the tank.

Description:
[0001]    The present invention relates to a machine for filling containers with at least one powdered product. 
         [0002]    Specifically, the present invention relates to a machine for filling capsules with at least one powdered pharmaceutical product, to which the following description will explicitly refer without therefore loosing in generality. 
       BACKGROUND OF THE INVENTION 
       [0003]    In the pharmaceutical industry, a machine for filling capsules with at least one powdered pharmaceutical product is known comprising a conveying device, which is continuously movable along a given path, and is provided with a plurality of pockets, each adapted to receive a corresponding bottom shell of a corresponding capsule; a rotating container for the product; and a metering wheel mounted to continuously rotate about a longitudinal axis thereof. 
         [0004]    The metering wheel is provided with a plurality of metering devices, each of which is fed by the metering wheel firstly through a withdrawal station of a given amount of product from the container and then along a portion of the aforesaid path phased with a corresponding pocket for transferring the product into the corresponding bottom shell. 
         [0005]    Each metering device comprises a cylinder and a piston axially movable under the bias of an actuating device comprising, in turn, a first and a second cam extending about the longitudinal axis of the metering wheel, a first tappet mounted on the piston and engaged in the first cam, and a second tappet mounted on the cylinder and engaged in the second cam. 
         [0006]    The first cam comprises a first segment parallel to the second cam so as to displace the cylinder and piston with reciprocally identical laws of motion, and at least one second segment, which is obtained in a block removably connected to the first segment at the withdrawal station, and is horizontally and differently oriented from the second cam to keep the piston on the upper surface of the product contained in the tank during the insertion of the cylinder in the product itself. 
         [0007]    The stop of the piston at the upper surface of the product allows to avoid the presence of air inside a metering chamber defined between the piston and the cylinder during the insertion of the cylinder in the product itself. 
         [0008]    Since the height of the product contained in the tank is selectively adjusted according to the chemical-physical features of the product and/or to the amount of the product which is to be withdrawn by the corresponding metering devices, the adjustment of the height of the product in the tank implies replacing the aforesaid block each time with a new block shaped to stop the piston at the new height of the product in the tank. 
         [0009]    The known machines of the above-described type thus display several drawbacks mainly deriving from the fact that the replacement of the blocks implies the availability and the storage of a relatively high number of blocks, severe operative difficulties for the operating personnel, and relatively long equipping times of the machines, and further allows to only discretely vary the height of the product contained in the tank. 
       SUMMARY OF THE INVENTION 
       [0010]    It is the object of the present invention to provide a machine for filling containers with at least one powdered product, which is free from the above-described drawbacks. 
         [0011]    According to the present invention, there is provided a machine for filling containers with at least one powdered product as claimed in the attached claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0012]    The present invention will now be described with reference to the accompanying drawings, which disclose a non-limitative embodiment thereof, in which: 
           [0013]      FIG. 1  is a schematic side view, with parts in section and parts removed for clarity, of a preferred embodiment of the machine of the present invention; 
           [0014]      FIG. 2  is a schematic perspective view, with parts removed for clarity, of the machine in  FIG. 1 ; 
           [0015]      FIG. 3  is a schematic longitudinal section of a first detail of the machine in  FIGS. 1 and 2 ; 
           [0016]      FIG. 4  is a schematic plane development of a second detail of the machine in  FIGS. 1 and 2 ; 
           [0017]      FIG. 5  is similar to  FIG. 4  and shows the detail in  FIG. 4  in three different operative positions; and 
           [0018]      FIG. 6  schematically shows the operating principle of the machine in  FIGS. 1 and 2 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0019]    With reference to  FIGS. 1 ,  2  and  3 , numeral  1  indicates as a whole a machine for filling capsules  2  of a known type with a powdered pharmaceutical product. Each capsule  2  comprises a substantially cup-shaped bottom shell  3  and a top shell (not shown) fitted onto the bottom shell  3  itself. 
         [0020]    The machine  1  includes a metering wheel  4 , in turn comprising a tubular vertical upright  5 , which has a longitudinal axis  6 , extends upwards from a fixed frame  7  of the machine  1 , and is engaged by a shaft  8 , which extends inside the upright  5  coaxially with axis  6 , and is rotationally coupled to the upright  5  to continuously rotate, with respect to the upright  5  itself and under the bias of an actuating device  9  of a known type, about axis  6 . 
         [0021]    The shaft  8  supports a feeding drum  10  including a substantially cylindrical casing  11 , which is coaxial with the axis  6 , is arranged with the concavity thereof facing downwards, is laterally bounded by a wall  12  extending about the upright  5 , and is closed at the top by a bottom wall  13 , which is substantially orthogonal to the axis  6 , and is fixed to one end of the shaft  8  projecting outwards of the upright  5 . 
         [0022]    On the external surface of the wall  12  a sprocket  14  defining part of a chain conveyor  15  of a known type is obtained, which is looped about a plurality of sprockets (of which only sprocket  14  is shown in  FIGS. 1 and 3 ) actuated by the device  9 , and is provided with a plurality of cup-shaped pockets  16  which have an upward-facing concavity, are uniformly distributed along the conveyor  15 , are each adapted to accommodate a corresponding bottom shell  3  arranged with the concavity thereof facing upwards, and are continuously fed by the conveyor  15  itself along a given path P. 
         [0023]    The wheel  4  further comprises an annular container  20 , which contains the powdered pharmaceutical product therein, and which extends over the sprocket  14  and is rotationally coupled to the frame  7  to continuously rotate, with respect to the frame  7  itself and under the bias of an actuating device of a known type (not shown), about a corresponding longitudinal axis  18  parallel to the axis  6 , at an angular speed which substantially differs from the angular speed of the drum  10  and, therefore, of the sprocket  16 . 
         [0024]    The drum  10  is provided with a plurality of metering devices  19 , which are uniformly distributed about the axis  6 , and are continuously fed by the drum  10  about the axis  6  itself. Each device  19  is fed by the drum  10  firstly through a withdrawal station  20 , wherein the device  19  withdraws a given amount of product from the container  17 , and thus phased with a corresponding pocket  16  along a segment of the path P extending through a filling station  21 , wherein the device  19  transfers the product into the corresponding bottom shell  3 . 
         [0025]    Each device  19  comprises a substantially cylindrical sleeve  22 , which has a longitudinal axis  23  substantially parallel to the axis  6 , extends through the casing  11 , is coupled in an axially sliding manner to the casing  11 , and is provided with a tappet roller  24 , which engages a cam  25  extending about the axis  6  and allows to selectively control the position of the sleeve  22  in a direction  26  parallel to the axes  6  and  18 . 
         [0026]    The sleeve  22  is further coupled in an angularly fixed manner to the drum  10  by means of a tappet roller  27 , which is mounted on the sleeve  22 , and is engaged in a corresponding slot  28  obtained through the casing  11  parallelly to the direction  26  to prevent the sleeve  22  from rotating about the axis  23 . Furthermore, the sleeve  22  supports, at an upper end thereof, a cylinder  29  by the side of the sleeve  22  and having a longitudinal axis parallel to the axis  23 . 
         [0027]    The device  19  further comprises a shaft  31 , which is fitted inside the sleeve  22  coaxially to the axis  23 , is slidingly coupled to the sleeve  22  to perform, with respect to the sleeve  22  itself, rectilinear displacements in the direction  26 , and has a lower end  32 , which protrudes at the bottom from the sleeve  22  in the direction  26 , and is fluid-tightly coupled with a pneumatic chamber  33  connected to a compressed air feeding device (known and not shown). 
         [0028]    The shaft  31  is displaced in the direction  26  by means of a tappet roller  34 , which is mounted on the shaft  31 , and is kept in contact with a cam  35  extending about the axis  6  parallelly to the cam  25  under the upward bias exerted on the shaft  31  by the compressed air fed to the chamber  33 . 
         [0029]    According to a variant (not shown) , the roller  34  is kept in contact with the cam  35  by means of at least one spring arranged between the sleeve  22  and the shaft  31 . 
         [0030]    Each shaft  31  is further coupled in an angularly fixed manner to the drum  10  by means of a tappet roller  36 , which is mounted on the shaft  31 , and is engaged in the corresponding slot  28  to prevent the shaft  31  itself from rotating about the axis  23 . 
         [0031]    At the upper end of the shaft  31  , by means of the interposition of a supporting bracket  37 , a substantially cylindrical piston  38  is fixed, which protrudes downwards from the bracket  37 , engages in a sliding manner the corresponding cylinder  29 , and has a diameter rounding down the diameter of the cylinder  29  itself. 
         [0032]    The operation of the machine  1  will now be described with reference to  FIGS. 3 and 6 , assuming the filling of only one bottom shell  3 , and starting from a moment in which the corresponding metering device  19  has been fed to the withdrawal station  20  ( FIGS. 3 and 6   a ) and faces the container  17 . 
         [0033]    By combining the displacement of the device  19  considered about the axis  6  with the action of the cams  25 ,  35 , the cylinder  29  and the piston  38  are lowered in the direction  26  at the station  20  with laws of motion which are substantially identical to each other, so as to be arranged in contact with the upper surface of the product contained in the container  20  ( FIG. 6   a ). 
         [0034]    At this point, the piston  38  is kept in contact with the upper surface of the product by engaging a tappet roller  39  mounted on the shaft  31  in a substantially horizontal cam  40  obtained along a lower edge of a block  41 , which has a helical shape, extends about the axis  6 , and slidingly engages a guiding channel  42  helically wound about the axis  6  itself. In other words, upon the rotation of the metering wheel  4  about the axis  6 , the roller  39  engages the cam  40  causing the disengagement of the roller  34  from the cam  35  and interrupting the descent of the piston  38  ( FIG. 6   a  and  6   b ). 
         [0035]    At the same time, the cylinder  29  is lowered into the product by means of the cam  25  so as to delimit a metering chamber  43 , which has a height H corresponding to the correct amount of product to be withdrawn, and is formed keeping the piston  38  substantially in contact with the upper surface of the product to avoid the presence of air within the chamber  43  itself ( FIG. 6   b ). 
         [0036]    After delimiting the chamber  43 , the roller  39  disengages the cam  40  allowing the roller  34  to engage the cam  35  again and the cams  25 ,  35  to lower the cylinder  29  again and, respectively, the piston  38  with laws of motion which are substantially identical to each other, and to displace the cylinder  29  substantially in contact with the bottom wall of the container  17  ( FIG. 6   c ). 
         [0037]    The piston  38  is then further lowered with respect to the cylinder  29  in the direction  26  to compact the product contained in the chamber  43  ( FIG. 6   c ) . The lowering of the piston  38  is obtained by engaging the roller  39  in a cam  44  and consequently releasing the roller  34  from the cam  35 . 
         [0038]    At this point, by combining the displacement of the device  19  about the axis  6  with the action of the cams  25 ,  35  and with the eccentric assembly of the container  17  with respect to the drum  10 , the device  19  is raised in the direction  26 , is extracted from the container  17 , and is fed in phase with a corresponding pocket  16  through the filling station  21 , at which the cylinder  29  and the piston  38  face the pocket  16  and, thus, the corresponding bottom shell  3  ( FIG. 6   d ). 
         [0039]    Finally, the piston  38  is lowered again with respect to the cylinder  29  in the direction  26  to transfer the product from the chamber  43  into the bottom shell  3  ( FIG. 6   e ) . The lowering of the piston  38  is obtained by engaging the roller  39  in a cam  45  mounted at the station  21  and consequently releasing the roller  34  from the cam  35 . 
         [0040]    With reference to  FIGS. 1 and 4 , the powdered pharmaceutical product is fed into the container  17  by means of a feeding hopper  46 , which is inserted in a container  17 , has the shape of a circular sector extending about the axis  18 , is open at the bottom, is coupled in an angularly fixed manner to the frame  7 , and is further slidingly coupled to the container  17  for performing, with respect to the container  17  itself, rectilinear displacements in the direction  26 . 
         [0041]    Furthermore, the hopper  46  defines a leveling element of the product inside the container  17 , and is thus arranged at a distance from the bottom wall of the container  17  equal to a height h of the product in the container  17  itself. 
         [0042]    The position of the hopper  46  in the direction  26  and, thus, the height h of the product in the container  17 , are selectively controlled according to the chemical-physical features of the product and/or to the amount of product which is to be withdrawn by the metering devices  19  by means of an actuating device  47  comprising a substantially flat and horizontal supporting bracket  48 , which is slidingly coupled to the frame  7 , and is further coupled by means of a screw/nut-screw coupling to a screw  49 , which extends in the direction  26 , and is coupled to an outlet shaft  50  of an electric motor  51  by means of the interposition of a pair of gears  52  so as to rotate under the propulsion of the motor  51  and to impart rectilinear displacements in the direction  26  to the bracket  48 . 
         [0043]    The adjustment of the position of the hopper  46  in the direction  26  and, thus, of the height h of the product in the container  17  necessarily implies a corresponding adjustment of the position of the piston  38  in the direction  26  so as to keep the piston  38  always substantially in contact with the upper surface of the product, regardless of the height h, when forming the metering chamber  43  ( FIGS. 6   a  and  6   b ). 
         [0044]    With this regard, the block  41  is displaced along the guiding channel  42  by means of a drive assembly  53  interposed between the motor  51  and the block  41  and comprising two driving shafts  54 ,  55 , which are mounted with respect to the frame  7  to rotate about corresponding longitudinal axes  56  parallel to the direction  26 , and are reciprocally connected by means of a drive belt  57  extending on a horizontal plane substantially orthogonal to the direction  26  itself. 
         [0045]    The shaft  54  is coupled to the outlet shaft  50  of the motor  51  by means of a pair of gears comprising the gear  52  mounted on the shaft  50  and a gear  58  mounted on the shaft  54 , while the shaft  55  is coupled by means of a pair of bevel gears  59  to a screw  60 , which extends transversally with respect to the direction  26 , and is coupled to the block  41  by means of a worm-helical wheel coupling. 
         [0046]    From the above, it is apparent that the actuation of the motor  51  implies the adjustment of the position of the hopper  46  in the direction  26  and, thus, of the height h of the product in the container  17  and, at the same time, the adjustment of the position of the block  41  along the guiding channel  42  ( FIG. 5 ), of the position of the cam  40  in the direction  26 , and, therefore, of the position of the piston  38  when forming the metering chamber  43 . 
         [0047]    Obviously, according to a variant (not shown), the drive assembly  53  is eliminated and replaced by an electric actuating motor of the screw  60  interconnected to and phased with the motor  51 . 
         [0048]    Furthermore, it is worth noting that the cam  35  is slidingly coupled to the cam  25  to perform rectilinear displacements in the direction  26  with respect to the cam  25  and under the bias of an actuating device (known and not shown), and to selectively control the height H of the metering chambers  43 . 
         [0049]    The machine  1  thus allows to selectively and continuously control the position of the piston  38  in the direction  26  when forming the metering chamber  43  according to the height h of the product in the container  17  by means of a single block  41 .