Tamping punch station and method of filling capsules in a tamping punch station

Abstract

A tamping punch station for filling capsules in a capsule filling machine is described. The machine includes a rotatably drivable dosing disk with bore holes and a filling device for filling the bore holes. Tamping punches and ejection punches are held on a punch support, and vertical movement of the punch support causes the tamping punches to press filling material into the bore holes and the ejection punches to eject pellets created by the tamping punches in the bore holes. A first drive rotates the dosing disk along punches and a second drive moves the punch support. The second drive includes at least two spindle drives acting on the punch support with respectively one spindle nut and respectively one vertical drive spindle guided in the spindle nut and at least two drive motors, which drive respectively one of the spindle drives for vertical movement of the punch support.

Claims

1. A tamping punch station for filling capsules with filling material in a capsule filling machine, the tamping punch station comprising: a rotatably drivable dosing disk, which comprises a group of bore holes, the dosing disk being movable through a cycle that includes a rest time, during which the dosing disk remains stationary, and a switch time, during which the dosing disk is movable between a plurality of positions; a filling device for filling the bore holes with the filling material; a punch support that is vertically moveable; a group of tamping punches and a group of ejection punches held on the punch support, wherein through vertical movement of the punch support the group of tamping punches for pressing the filling material into the bore holes and the group of ejection punches for ejecting pellets created by the tamping punches in the bore holes are moved into the bore holes; a first drive device for incremental rotation of the dosing disk along the group of tamping punches and the group of ejection punches; and a second drive device for the vertical movement of the punch support, wherein the second drive device is operable separately from the first drive device such that rotation of the dosing disk is varied independent of vertical movement of the punch support to allow for variation in a ratio between the rest time and the switch time, the second drive device comprises at least two spindle drives acting on the punch support, each spindle drive having a respective spindle nut and a respective vertical drive spindle having a first end extending through a holding plate, a second end fastened to the punch support, and guided in the spindle nut, and the holding plate extending in parallel with the dosing disk and having a first surface facing the dosing disk and a second surface opposite from the first surface, and the second drive device comprises at least two drive motors, each drive motor axially fixedly mounting one of the spindle nuts against the second surface of the holding plate, and driving one of the at least two spindle drives for the vertical movement of the punch support by rotationally driving the one of the spindle nuts to vertically move the first end of the respective vertical drive spindle relative to the holding plate.

2. The tamping punch station according to claim 1, wherein: the punch support is at least one of a support plate or a support bridge; and a first spindle drive and a second spindle drive of the at least two spindle drives are fastened on opposing sides of the at least one of the support plate or the support bridge.

3. The tamping punch station according to claim 1, wherein each drive motor of the at least two drive motors is an electric motor.

4. The tamping punch station according to claim 1, wherein one of each of the axially fixedly mounted spindle nuts or each vertical drive spindle is arranged in a blind hole of each one of the at least two drive motors at different times.

5. The tamping punch station according to claim 1, wherein: each drive motor of the at least two drive motors is a hollow shaft motor; and each axially fixedly mounted spindle nut is respectively arranged in a hollow shaft of a respective one of the at least two drive motors.

6. The tamping punch station according to claim 1, wherein the first drive device comprises a servomotor.

7. The tamping punch station according to claim 1, wherein the first drive device comprises a torque motor.

8. The tamping punch station according to claim 1, wherein the dosing disk comprises at least two groups of bore holes.

9. The tamping punch station according to claim 1, wherein: the dosing disk comprises n groups of bore holes, wherein n>2; and the group of tamping punches is n1 groups of tamping punches held on the punch support.

10. The tamping punch station according to claim 1, wherein: each of the at least two drive motors is a hollow shaft motor with a first end having a hollow shaft, the first end in contact with the second surface of the holding plate; the one of the spindle nuts is arranged within the first end of the hollow shaft motor; and the first end of the hollow shaft motor is in contact with the second surface of the holding plate to axially fixedly mount the one of the spindle nuts against the second surface of the holding plate.

11. The tamping punch station according to claim 10, wherein: each of the at least two drive motors is a hollow shaft motor with a first end having a hollow shaft, the first end in contact with the second surface of the holding plate; and each spindle nut has a radially-extending flange at a first end that is engaged with a corresponding inner surface of a respective hollow motor and with the second surface of the holding plate to axially fixedly mount the spindle nut against the second surface of the holding plate.

12. The tamping punch station according to claim 1, further comprising: a control device receiving measured pressing forces occurring while pressing the filling material into the bore holes, and regulating the pressing forces to meet a defined mass and density for the pellets.

13. The tamping punch station according to claim 1, further comprising: pressing force sensors with which pressing forces occurring during production of the pellets are measured.

14. A capsule filling machine for filling capsules put together from a capsule top part and a capsule bottom part, the capsule filling machine comprising: a conveyor wheel, on a perimeter of which a plurality of capsule holders is provided, each of which has a group of capsule receivers for respectively receiving one capsule; a conveyor wheel drive, with which the conveyor wheel can be rotated incrementally so that the capsule holders move incrementally along a conveyor track; and a plurality of process stations arranged along the conveyor track, wherein the process stations comprise at least one feeding station for feeding capsules to be filled into the capsule receivers, at least one opening station for opening the capsules to be filled by separating the capsule top parts from the capsule bottom parts, at least one tamping punch station according to claim 1, at least one closing station for closing the filled capsules by connecting the capsule top parts with the capsule bottom parts, and at least one ejection station for ejecting the filled capsules.

15. A method for filling capsules with filling material in a tamping punch station of a capsule filling machine, the tamping punch station comprising a rotatably drivable dosing disk, which comprises a group of bore holes, the dosing disk being movable through a cycle that includes a rest time, during which the dosing disk remains stationary, and a switch time, during which the dosing disk is movable between a plurality of positions, a filling device for filling the bore holes with the filling material, a punch support that is vertically moveable, a group of tamping punches and a group of ejection punches held on the punch support, wherein through vertical movement of the punch support the group of tamping punches for pressing the filling material into the bore holes and the group of ejection punches for ejecting pellets created by the tamping punches in the bore holes are moved into the bore holes, a first drive device for incremental rotation of the dosing disk along the group of tamping punches and the group of ejection punches, and a second drive device for vertical movement of the punch support, the method comprising: rotating the dosing disk into a rotational position in which the group of bore holes is aligned with the group of tamping punches using the first drive device; moving, using the second drive device, the punch support vertically so as to move the group of tamping punches for pressing the filling material filled in the bore holes into pellets into the bore holes, wherein the group of tamping punches is held for a pressure hold time in the bore holes and then retracted from the bore holes; rotating the dosing disk into a rotational position in which the bore holes are aligned with the group of ejection punches using the first drive device; and moving the punch support vertically so as to move the group of ejection punches into the bore holes for ejection of the pellets created by the group of tamping punches in the bore holes, wherein: the pressure hold time of the group of tamping punches is varied between different filling processes through variable control of at least one of the first drive device or the second drive device, the second drive device is operable separately from the first drive device such that rotating the dosing disk is varied independent of moving the punch support to allow for variation in a ratio between the rest time and the switch time, the second drive device comprises at least two spindle drives acting on the punch support, each spindle drive having a respective spindle nut and a respective vertical drive spindle having a first end extending through a holding plate, a second end fastened to the punch support, and guided in the spindle nut, and the holding plate extending in parallel with the dosing disk and having a first surface facing the dosing disk and a second surface opposite from the first surface, and the second drive device comprises at least two drive motors, each drive motor axially fixedly mounting one of the spindle nuts against the second surface of the holding plate, and driving one of the spindle drives for the vertical movement of the punch support by rotationally driving the one of the spindle nuts to vertically move the first end of the respective vertical drive spindle relative to the holding plate.

16. The method according to claim 15, further comprising: rotating the dosing disk in at least one of a first rotational direction or a second rotational direction after moving the group of tamping punches for pressing the filling material and before rotating the dosing disk into the rotational position in which the bore holes are aligned with the group of ejection punches by means of the first drive device until the dosing disk again assumes the rotational position in which the group of bore holes is aligned with the group of tamping punches.

17. The method according to claim 15, wherein movement of the group of ejection punches into and out of the bore holes takes place by the second drive device or that the movement of the group of ejection punches into and out of the bore holes takes place by a third drive device such that the group of ejection punches is moveable independently of the group of tamping punches.

18. The method according to claim 15, further comprising: receiving, by a control device, measured pressing forces occurring while pressing the filling material into the bore holes; and regulating, but the control device, the pressing forces to meet a defined mass and density for the pellets.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views unless otherwise noted, and wherein:

(2) FIG. 1 is a first sectional view of a tamping punch station according to an embodiment of the invention;

(3) FIG. 2 is a second sectional view of the tamping punch station from FIG. 1;

(4) FIG. 3 is a sectional view of the tamping punch station from FIG. 1 in a second operating state;

(5) FIG. 4 is a sectional view of the tamping punch station from FIG. 1 in a third operating state; and

(6) FIG. 5 is schematic top view of a rotary capsule filling machine in which embodiments of the tamping punch station described herein may be implemented.

DETAILED DESCRIPTION

(7) The tamping punch station shown in the figures forms part of a capsule filling machine for filling for example hard gelatin capsules with for example a powdered filling material. One example of a capsule filling machine 50 is shown schematically in FIG. 5. The capsules 52 generally consist of a capsule top part and a capsule bottom part. The capsule filling machine 50 comprises a conveyor wheel 54, on the perimeter of which a plurality of capsule holders 56 is provided, which have respectively a group of capsule receivers 56a, in which respectively one capsule or respectively one capsule bottom part is held. Furthermore, the capsule filling machine 50 comprises a conveyor wheel drive 58, with which the conveyor wheel 54 can be rotated incrementally in the direction of the arrow 60 so that the capsule holders 56 move incrementally along a conveyor track. Moreover, the capsule filling machine 50 comprises a plurality of process stations 01 to 12 arranged along the conveyor track, among other things at least one feeding station 01, 02 for feeding capsules to be filled into the capsule receivers, at least one opening station 03, 04 for opening the capsules 52 to be filled by separating the capsule top parts from the capsule bottom parts, a tamping punch station 05, 06, 07 according to the teachings herein, at least one closing station 08, 09 for closing the filled capsules 52 by connecting the capsule top parts with the capsule bottom parts and at least one ejection station 10, 11 for ejecting the filled capsules. The wheel 62 in FIG. 5 represents a location of one example of the tamping punch station described herein relative to the remainder of the capsule filling machine 50.

(8) A tamping punch station shown in more detail in FIGS. 1-4 has a dosing disk 13, which has several groups of bore holes 12 distributed about its perimeter. A drive shaft 16 is connected with the dosing disk 13 via a flange 14, which is rotatably drivable around the rotational axis 20 by a first drive motor 18, for example a servomotor or torque motor. The dosing disk 13 is also rotated with the drive shaft 16. A base 24, which carries a tamping disk 26, is arranged on a holding plate 22 not rotated with the dosing disk 13. The tamping disk 26 closes the bore holes 12 in the area of the tamping punches 28 downwards and forms a counter bearing for the tamping punches 28. The tamping punches 28 are fastened on a plate- or respectively bridge-shaped punch support 32 via springs 30. In the example shown, drive spindles 34 are fastened on opposite-lying ends of the punch support 32. The drive spindles 34 are received in an axially displaceable manner in guides 36 and engage via an external thread with spindle nuts 38. As shown, the spindle nuts 38 are arranged respectively in an axially fixed manner on the rotor of a hollow shaft motor 40 designed as a hollow shaft and are rotatable with the rotor of the hollow shaft motor 40. As can be seen in FIG. 1, the drive spindles 34 extend through the holding plate 22 into the hollow shafts of the hollow shaft motors 40. Through rotation of the spindle nuts 38, the drive spindles 34 and with them the punch support 32 with the tamping punches 28 and ejection punches explained below are moved in the vertical direction. For example, five groups of tamping punches 28 can be provided. Six groups of bore holes 12 can then be designed in the dosing disk 13, for example. A filling trough 42 is filled with the filling material to be filled into the bore holes.

(9) Referring now to FIG. 2, a group of ejection punches 44 is also held on the punch support 32. As can be seen in FIG. 2, the tamping disk 26 does not cover the bottom side of the bore holes 12 in the area of the ejection punches 44 so that these bore holes 12 are open towards the bottom. A stripping device 46 for stripping filling material from the top side of the dosing disk 13 can be seen in the area of the ejection punches 44.

(10) During operation, the dosing disk 13 is rotated incrementally via the drive motor 18, wherein the groups of bore holes 12 are respectively aligned with a group of tamping punches 28 or respectively the group of ejection punches 44. The spindle nuts 38 are thereby rotated via the hollow shaft motors 40 and thereby the drive spindles 34 and thus the punch support 32 with the tamping punches 28 and the ejection punches 44 are moved in the vertical direction. In this way, the tamping punches 28 in the bore holes 12 successively form pellets from the powdered filling material located in the filling trough 42. The bore holes 12, which are aligned with the ejection punches 44, are open on their bottom side, as mentioned. The ejection punches 44 can thereby eject downwards the pellets created in the bore holes 12 into capsule bottom parts aligned for this, which are located in capsule holders of the capsule filling machine. The movement of the tamping punches 28 downwards and into the bore holes 12 can be seen in FIGS. 3 and 4.

(11) Moreover, a control device 48 (shown schematically only in FIG. 1) controls in a coordinated and suitable manner the drive motor 18 on one hand and the hollow shaft motors 40 on the other hand. The control device 48 may be a computer or other controller executing instructions stored in its memory or external memory to provide signals to motors 18, 40 through any suitable communication means to perform the actions described herein. Due to the separation of the drive means for the dosing disk 13 on one hand and the punch support 32 with the tamping punches 28 and the ejection punches 44 on the other hand, it is possible to variably adjust the switch and rest times. It is also possible to change the stroke length of the punch support 32 and thus of the tamping punches 28 and the ejection punches 44. Suitable sensors can also be provided, with which for example the pressing force in the area of the tamping punches 28 is measured. The measurement results can be sent to one or more inputs of the control device 48 and the control device 48 can execute suitable control circuits at one or more outputs to meet predetermined pressing forces.

(12) Although FIGS. 1-4 show a tamping punch station with several groups of tamping punches 28, a design is also possible in which only one group of tamping punches 28 and one group of ejection punches 44 is provided. It is then possible that the dosing disk 13 is rotated by the drive motor 18 such that the, if applicable, single group of bore holes 12 designed in the dosing disk 13 is aligned with the tamping punches 28. The tamping punches 28 can then be moved into and out of the bore holes 12 multiple times in succession vertically driven by the hollow shaft motors 40 so that a pellet is created in each bore hole 12 successively in several pressing procedures. The dosing disk 13 can then be rotated further so that the group of bore holes 12 is aligned with the group of ejection punches 44 and the ejection punches 44 can eject the pellets produced in the bore holes 12 into capsule bottom parts in the manner explained above. In this case, third drive means (not shown) are provided, with which the ejection punches are moveable independently of the tamping punches. This procedure is offered in particular in the field of galenics (i.e., for galenic formulations). Particularly compact laboratory tamping punch stations can be used.