Abstract:
The bottom shell of a capsule is filled with at least two products, contained in respective tanks, by means of a metering device, which has a metering chamber for receiving a given quantity of product from each tank; and a transfer chamber, which receives and transfers the product from the metering chamber to the bottom shell, and has a weighing device for weighing the product inside the transfer chamber.

Description:
[0001]    The present invention relates to a machine for filling capsules or similar with at least two products. 
         [0002]    More specifically, the present invention relates to a machine for filling capsules with pharmaceutical products in granules, to which the following description refers purely by way of example. 
       BACKGROUND OF THE INVENTION 
       [0003]    In the pharmaceutical industry, a machine for filling capsules with pharmaceutical products in granules is known comprising a conveying device moving continuously along a given path and having a number of pockets, each for receiving a respective bottom shell of a capsule; two tanks of respective products; and a metering wheel mounted to rotate continuously about a substantially vertical longitudinal axis. 
         [0004]    The metering wheel has a number of metering devices, each of which is moved by the metering wheel along a portion of the bottom shell path, in time with, and so as to transfer a given quantity of each product into, a respective bottom shell. 
         [0005]    Each metering device comprises a substantially cylindrical metering chamber for receiving a given quantity of product from each tank; a feed chute for feeding the product from the metering chamber into the relative bottom shell; and a piston, which defines the bottom of the metering chamber, and moves along the metering chamber between an open position and a closed position opening and closing the feed chute respectively. 
         [0006]    Because the second product is fed into the metering chamber after the first has been fed to the feed chute and the piston has moved back into the closed position, the product inside the metering chamber is weighed by a weighing device, in this case a capacitive transducer, fitted inside the metering chamber. 
         [0007]    Starting with the metering chamber empty and the piston in the closed position, the operating sequence by which the product inside the metering chamber is weighed comprises the steps of: 
         [0008]    lowering the piston to enable the weighing device to weigh the portion of the piston projecting inside the metering chamber; 
         [0009]    raising the piston into a position corresponding to a given volume of the metering chamber; 
         [0010]    filling the metering chamber with the product; 
         [0011]    lowering the piston to enable the weighing device to measure the total weight of the piston portion projecting inside the metering chamber, and the product inside the metering chamber; and 
         [0012]    lowering the piston into the open position to feed the product along the feed chute into the bottom shell. 
         [0013]    The two weights are measured by moving the piston at constant speed from the same position along the metering chamber, so the weight of the piston portion projecting inside the metering chamber has exactly the same effect on both, and the weight of the product inside the metering chamber can be calculated as the difference between the two weights recorded by the weighing device. 
         [0014]    Because the above operating sequence has to be performed twice—once for each product fed into the metering chamber—for each complete turn of the metering wheel about its longitudinal axis, and, each time, the piston has to perform a relatively large number of movements along the metering chamber, some merely to weigh the piston portion projecting inside the metering chamber, known machines of the above type have several drawbacks, mainly due to the relatively high travelling speed of the piston along the metering chamber, which jeopardizes not only correct filling of the metering chamber, but also correct weighing of the piston portion projecting inside the metering chamber, and each product inside the metering chamber. 
       SUMMARY OF THE INVENTION 
       [0015]    It is an object of the present invention to provide a machine for filling capsules or similar with at least two products, designed to eliminate the above drawbacks. 
         [0016]    According to the present invention, there is provided a machine for filling capsules or similar with at least two products, as claimed in Claims  1  to  13 . 
         [0017]    The present invention also relates to a method of filling capsules or similar with at least two products. 
         [0018]    According to the present invention, there is provided a method of filling capsules or similar with at least two products, as claimed in Claims  14  to  20 . 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]    A non-limiting embodiment of the present invention will be described by way of example with reference to the accompanying drawings, in which: 
           [0020]      FIG. 1  shows a schematic view in perspective of a preferred embodiment of the machine according to the present invention; 
           [0021]      FIG. 2  shows a schematic plan view, with parts removed for clarity, of a detail of the  FIG. 1  machine; 
           [0022]      FIG. 3  shows operating schematics of the  FIG. 1  machine. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0023]    With reference to  FIGS. 1 and 3 , number  1  indicates as a whole a machine for filling known capsules (not shown) with at least one pharmaceutical product in granules. Each capsule (not shown) comprises a substantially cup-shaped bottom shell  2 , and a top shell (not shown) closing bottom shell  2 . 
         [0024]    Machine  1  comprises a metering wheel  3 , in turn comprising a supporting shaft (not shown), which has a substantially vertical longitudinal axis  4 , is fitted to a fixed frame  5  of machine  1 , is rotated continuously about axis  4  and with respect to frame  5  by a known drive device (not shown), and supports a metering drum  6 . 
         [0025]    Drum  6  comprises a bottom disk  7 , an intermediate disk  8 , and a top disk  9 , which are coaxial with and perpendicular to axis  4 , and are connected in angularly fixed manner to one another and to the supporting shaft (not shown) to rotate about axis  4 . 
         [0026]    On the outer surface of disk  7  are formed: a sprocket  10  coaxial with axis  4  and forming part of a known conveying device  11  for feeding bottom shells  2  along a given path P; and an annular funnel  12  extending between sprocket  10  and disk  8 , and tapering towards sprocket  10 . 
         [0027]    Device  11  comprises a chain conveyor  13  looped about a number of powered sprockets (of which only sprocket  10  is shown in  FIG. 3 ) and comprising a number of substantially cup-shaped pockets  14 , which are positioned with their concavities facing upwards, are equally spaced along conveyor  13 , are each designed to house a respective bottom shell  2  with its concavity facing upwards, and are fed continuously by conveyor  13  along path P and beneath funnel  12 . 
         [0028]    In the example shown, frame  5  is fitted with two tubular containers  15 ,  16  ( FIGS. 1 and 3   b ), which are mounted on top of disk  9 , are arranged about axis  4 , each extend less than 180° about axis  4 , are open at the top and bottom in a direction  17  parallel to axis  4 , and each house a respective pharmaceutical product in granules. 
         [0029]    Drum  6  comprises a number of metering devices  18  equally spaced about axis  4 , and which are moved by drum  6  about axis  4  and along a portion of path P in time with respective pockets  14 , so as each to withdraw a given amount of pharmaceutical product from each container  15 ,  16 , and feed it into relative bottom shell  2 . 
         [0030]    Each device  18  comprises a substantially cylindrical metering chamber  19 , which extends through top disk  9 , has a longitudinal axis  20  parallel to axis  4 , and is offset radially with respect to funnel  12 ; and a substantially cylindrical transfer chamber  21 , which is formed through intermediate disk  8 , has a longitudinal axis  22  parallel to axis  4 , and is aligned in direction  17  with funnel  12 . 
         [0031]    Chamber  21  is bounded laterally by a bushing  23  fitted inside chamber  21 , coaxially with axis  22 , and comprising a capacitive transducer  24  integrated in bushing  23  and forming part of a weighing device  25  for weighing the product inside chamber  21 . 
         [0032]    Device  25  also comprises a known electric connector (not shown) coaxial with axis  4  and in turn comprising a fixed member fitted to frame  5 , and a movable member fixed to drum  6  and connected electrically to capacitive transducers  24  of devices  18 . 
         [0033]    Bushing  23 , capacitive transducer  24 , and weighing device  25  are described and illustrated in the Applicant&#39;s Patent Application WO-2006/035285-A2, which is fully included in the present Application. 
         [0034]    Chamber  19  is connected to chamber  21  by a feed chute  26  formed through disk  9 , and is closed at the bottom by the top end of a piston  27 , which is mounted coaxially with axis  20 , extends through disks  7 ,  8  and  9 , and is fitted in axially sliding, angularly fixed manner to drum  6  to slide, with respect to drum  6 , straight along chamber  19  in direction  17 . 
         [0035]    Piston  27  has a changeable top portion  27   a,  which is bounded at the top by a flat surface  28  sloping with respect to axis  20 , is fitted removably to a bottom portion  27   b  of piston  27 , and can be changed according to the size of chamber  19 . 
         [0036]    As shown in  FIG. 3   e , pistons  27  are moved along respective chambers  19  by an actuating device  29  comprising a known cam  30 , and, for each piston  27 , a respective cam follower roller  31  engaging cam  30 . 
         [0037]    Cam  30  extends about axis  4 , and, at each container  15 ,  16 , has a respective movable portion, which is movable in direction  17  independently of the other movable portion to selectively control the volume of chambers  19  at each container  15 ,  16 . 
         [0038]    Bach roller  31  is fitted in rolling manner to a top sleeve  32 , which is fitted slidably to respective piston  27 , is coaxial with relative axis  20 , and is normally held contacting a top stop ring  33 , fixed to piston  27 , by a spring  34  fitted to piston  27 , coaxially with axis  20 , and interposed between sleeve  32  and a bottom sleeve  35  fixed to piston  27  and also coaxial with axis  20 . 
         [0039]    Chamber  21  is closed at the bottom by a shutter  36 , which extends through disks  8  and  9  in direction  17 , has a longitudinal axis  37  offset with respect to axis  22 , projects from the top of disk  9  in direction  17 , and is fitted td drum  6  to slide, with respect to drum  6  and straight in direction  17 , between an open position ( FIG. 3   a ) opening chamber  21 , and a closed position ( FIG. 3   b ) closing chamber  21 . 
         [0040]    Shutter  36  is normally held in the closed position by a spring  38  interposed between disk  9  and shutter  36 , and is moved into the open position by its top end engaging a cam  39  fixed to frame  5  ( FIG. 3   a ). 
         [0041]    Shutter  36  comprises a bottom portion  36   a  made of insulating material with a low or zero dielectric constant; and a top portion  36   b  made, for example, of metal. 
         [0042]    Portion  36   a  is substantially L-shaped and comprises a supporting rod  40 , which slides inside a groove (not shown) formed through bushing  23  and parallel to direction  17 , has a wedge-shaped portion  41  for dislodging any product clogging chamber  21 , and, on its bottom free end, has a stopper plate  42  sloping with respect to axis  37 . 
         [0043]    Operation of machine  1  will now be described with reference to  FIG. 3  and to one bottom shell  2  only, and as of the instant ( FIG. 3   a ) in which: 
         [0044]    relative metering device  18  is located upstream from container  15  in the rotation direction of wheel  3  about axis  4 ; 
         [0045]    relative shutter  36  is in the open position; and 
         [0046]    relative piston  27  projects outwards of chamber  19  and cooperates with a suction device  43  for removing any product residue from chamber  19 . 
         [0047]    At this point, device  18  and relative bottom shell  2  are advanced in time with each other; piston  27  is lowered in direction  17  into a position closing chute  26  and corresponding to a given volume of chamber  19 ; shutter  36  is moved into the closed position to allow capacitive transducer  24  to weigh the portion of shutter  36  projecting inside chamber  21 ; and device  18  is fed beneath container  15  to allow a given quantity of the first product to drop by gravity into chamber  19  ( FIG. 3   b ). 
         [0048]    Next, device  18  disengages container  15  ( FIG. 3   c ); and piston  27  is moved into position to open chute  26 , so the product inside chamber  19  slides down chute  26  into chamber  21  ( FIG. 3   d ). 
         [0049]    Finally, shutter  36  is moved into the open position, so the product in chamber  21  drops into bottom shell  2 , and capacitive transducer  24  measures the total weight of the portion of shutter  36  projecting inside chamber  21 , and the product inside chamber  21 ; and piston  27  is raised to close chute  26 , project outwards of chamber  19 , and cooperate with a second suction device  44  upstream from container  16  in the rotation direction of wheel  3  about axis  4  ( FIG. 3   a ). 
         [0050]    Because the two weights are measured by moving shutter  36  at constant speed in direction  17  and between the same positions along axis  22 , the weight of the portion of shutter  36  projecting inside chamber  21  affects both weight measurements in exactly the same way, so weighing device  25  can calculate the weight of the product inside chamber  21  as the difference between the two weights recorded by capacitive transducer  24 . 
         [0051]    Obviously, the above operating sequence relative to container  15  is repeated for container  16 . 
         [0052]    It should be pointed out that each piston  27  may be locked selectively in the closed position, preventing product feed along chute  26  into chamber  21 , when pocket  14  contains no bottom shell  2 , or when only one product is to be fed into bottom shell  2  and its weight checked by an auxiliary weighing device off wheel  3 . 
         [0053]    With reference to  FIGS. 2 and 3   e , pistons  27  are locked selectively into position closing respective chutes  26  by a lock device  45  comprising, at each container  15 ,  16 , a respective actuating cylinder  46 , which is fixed to frame  5 , beneath metering devices  18 , has a longitudinal axis  47  parallel to direction  17  and offset radially with respect to axes  20 , and supports a substantially flat cam  48  fitted to the output rod of cylinder  46  and perpendicular to axis  47 . 
         [0054]    Device  45  also comprises, for each device  18 , a respective crank  49  hinged to disk  7  to rotate, with respect to disk  7 , about a hinge axis  50  substantially parallel to direction  17 . 
         [0055]    Cylinder  46  moves cam  48  in direction  17  between a lowered rest position, in which cam  48  is positioned clear of the path of cranks  49  about axis  4 , and a raised work position, in which cam  48  is positioned along the path of cranks  49  to intercept and move crank  49  of relative device  18  into a work position (shown in  FIG. 3   e  and by the dash line in  FIG. 2 ) in which crank  49  is positioned beneath piston  27  to prevent it being lowered into position to open chute  26 . 
         [0056]    Crank  49  is moved from the work position to a rest position—shown by the dash line in  FIG. 3   e , and in which crank  49  releases piston  27 —by a return spring (not shown) and by a further cam (not shown) identical to cam  48 . 
         [0057]    In connection with the above, it should be pointed out that the upward thrust exerted by spring  34  on top sleeve  32  is less than the downward thrust exerted by cam  30  on follower roller  31 , and therefore on sleeve  32 , when piston  27  is locked in the closed position, thus enabling sleeve  32  to move down in opposition to spring  34 , and piston  27  to remain stationary in direction  17 . 
         [0058]    Machine  1  has several advantages, mainly due to transfer chamber  21 , i.e. an intermediate chamber between metering chamber  19  and bottom shell  2 , which allows metering device  18  to fill chamber  19  correctly with each product, and weighing device  25  to correctly weigh the portion of shutter  36  projecting inside chamber  21 , and the product inside chamber  21 .