GATE FOR A TABLET DISCHARGE OF A TABLET PRESS AND METHOD FOR ACTUATING A GATE

Abstract

A tablet press comprises a gate that defines a first switching position that feeds tablets into a first tablet outlet and at least a second switching position that feeds tablets into at least one second tablet outlet. The table press further comprises a control apparatus and a drive apparatus. The drive apparatus is configured to be actuated by the control apparatus to move the gate from a home position defined as one of the first switching position and the at least a second switching position into a target position defined as a switching position that is not the home position. The gate is moved from the home switching position at a speed of movement toward the target position such that the speed of movement of the gate is reduced before the target position is reached.

Claims

1. A tablet press comprising: a gate of a tablet discharge defining a first switching position that feeds tablets into a first tablet outlet and at least a second switching position that feeds tablets into at least one second tablet outlet; a control apparatus; and a drive apparatus configured to be actuated by the control apparatus to move the gate from a home position defined as one of the first switching position and the at least a second switching position into a target position defined as a switching position that is not the home position, wherein the gate is moved from the home switching position at a speed of movement toward the target position and, wherein the speed of movement of the gate is reduced before the target position is reached.

2. The tablet press according to claim 1, wherein the control apparatus is configured to actuate the drive apparatus to reduce the speed of movement of the gate such that it stops before reaching the target position, and wherein the speed of movement of the gate is then increased such that the gate is subsequently moved into the target position.

3. The tablet press according to claim 2, wherein the tablet discharge comprises at least one discharge channel.

4. The table press according to claim 3, wherein the gate comprises at least one gate element pivotably mounted within the at least one discharge channel of the tablet discharge between the home position and the target position.

5. The tablet press according to claim 4, wherein the control apparatus is configured to actuate the drive apparatus such that the speed of movement is reduced when there is a distance of more than 10 mm between the at least one gate element and an inner wall of the at least one discharge channel bordering the at least target position.

6. The tablet press according to claim 5, wherein the at least one discharge channel has at least one section that expands along a tablet discharge direction.

7. The tablet press according to claim 6, wherein the at least one expanding section is located upstream from a region swept by the gate element during its pivoting movement.

8. The tablet press according to claim 6, wherein at least one expanding section expands opposing walls of the discharge channel.

9. The tablet press according to claim 6, wherein the expansion of the at least one expanding section has a width of at least 10 mm.

10. The tablet press according to claim 2, wherein the control apparatus is configured to actuate the drive apparatus so that the speed of movement of the gate is reduced directly before reaching an expanding section or after reaching the expanding section.

11. A rotary tablet press comprising; a rotor configured to be rotated by a rotary drive, wherein the rotor comprises an upper punch guide for upper punches of the rotary tablet press, a lower punch guide for lower punches of the rotary tablet press, and a die plate arranged between the punch guides, wherein the upper and lower punches interact with cavities in the die plate; a filling apparatus configured to deposit filling material into the cavities in the die plate; at least one upper pressing apparatus and at least one lower pressing apparatus that are configured to interact with the upper punches and the lower punches, respectively to press the filling material in the cavities in the die plate into tablets; an ejection apparatus configured to eject tablets generated in the cavities; and a tablet discharge configured to accept the ejected tablets and comprising at least one gate configured to move between a home position and a target position, wherein a speed of movement of the gate is reduced before the target position is reached.

12. A method for actuating a gate of a tablet discharge of a tablet press wherein the gate is moved between a first switching position in which tablets are fed to a first tablet outlet, and at least one second switching position in which tablets are fed to at least one second tablet outlet, the method comprising: moving the gate from a home position defined as one of the first switching position and the at least a second switching position into a target position that is not the home position at a speed of movement toward the target position, wherein the speed of movement of the gate is reduced before the target position is reached.

13. The method according to claim 12, wherein the speed of movement of the gate is reduced so that the gate stops before reaching the target position, and wherein the speed of movement of the gate is subsequently increased to move the gate into the target position.

14. The method according to claim 13, wherein the gate further comprises at least one gate element pivotably mounted in at least one discharge channel of the tablet discharge between the home position and the target position, wherein the speed of movement is reduced when there is a distance of more than 10 mm, between the at least one gate element and an inner wall of at least one discharge channel bordering the target position.

15. The method according to claim 14, wherein the speed of movement of the gate is reduced directly before or after reaching an expanding section of at least one of the tablet outlets.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] An exemplary embodiment of the invention is explained below in greater detail with reference to figures. Schematically:

[0028] FIG. 1 illustrates a cross-sectional view of an embodiment of a rotary press;

[0029] FIG. 2 illustrates a top plan view of an embodiment of a gate of the rotary tablet press shown in FIG. 1 in a first operating position;

[0030] FIG. 3 illustrates a top plan view of the gate from FIG. 2 in a second operating position;

[0031] FIG. 4 illustrates a top plan view of the gate from FIG. 2 in a third operating position; and

[0032] FIG. 5 illustrates a top plan view of the gate from FIG. 2 in a fourth operating position.

[0033] The same reference numbers refer to the same objects in the figures unless indicated otherwise.

DETAILED DESCRIPTION OF THE INVENTION

[0034] The rotary tablet press shown in FIG. 1 comprises a rotor that is rotationally driven by a rotary drive (not shown) with a die plate 10 which has a plurality of cavities 12. The cavities 12 can for example be formed by holes in the die plate 10. Furthermore, the rotor comprises a plurality of upper punches 14 and lower punches 16 that rotate synchronously with the die plate 10. In each case, a pair consisting of an upper punch 14 and lower punch 16 is thus assigned to a cavity 12. The axial movement of the upper punches 14 and lower punches 16 during the rotation of the rotor is controlled by upper control cam elements 18 and lower control cam elements 20. The rotary tablet press moreover comprises a filling apparatus 22 which has a filling chamber 24. The filling apparatus 22 moreover comprises a funnel-shaped filling material reservoir 26 which is connected by a feed section 28 to the filling chamber 24. In this manner, the powdered filling material in the present example passes under the force of gravity from the filling material reservoir 26 via the feed section 28 into the filling chamber 24, and passes therefrom via a filling opening provided in the bottom side of the filling chamber 24 into the cavities 12 of the die plate 10, again under the force of gravity.

[0035] Moreover, the rotary tablet press comprises a pressing apparatus 30. The pressing apparatus 30 possesses a pre-pressing apparatus with an upper pre-pressing roller 32 and a lower pre-pressing roller 34, as well as a main pressing apparatus with an upper main pressing roller 36 and a lower main pressing roller 38. Furthermore, the rotary tablet press comprises an ejecting apparatus 40, in the present case with a scraper 42 which supplies the tablets 74 produced in the rotary tablet press to a tablet discharge 46.

[0036] A control apparatus for operating the rotary press is shown with reference number 48. The control apparatus 48 can for example comprise a computer processor, microprocessor, microcontroller, or similar device. The control apparatus 48 is connected by lines (not shown) to, inter alia, the rotary drive of the rotor.

[0037] A gate 50 shown in FIGS. 2 to 5 is located in the tablet discharge 46. The gate 50 has a first discharge channel 52 and a second discharge channel 54. The first and the second discharge channel 52, 54 are separated by a partition wall 56 from each other. A first gate flap 58 located in the partition wall 56 is mounted pivotably about a first pivot axis 60 between the first switching position shown in FIG. 2 and a second switching position (not shown) in which the free end 62 of the gate flap 58 lies against the opposite wall 64 of the second discharge channel 54. In FIGS. 2 to 5, tablets flow from top to bottom through the gate 50. Downstream from the first gate flap 58, a second gate flap 66 is pivotably mounted about a second pivot axis 68 in the second discharge channel 54 between a first switching position shown in FIG. 2 and a second switching position shown in FIG. 4. Downstream from the second gate flap 66, a partition wall 70 can be seen that defines a third discharge channel 72. Drives of a drive apparatus are provided such as electric motor or electromagnetic drives to pivot the first gate flap 58 and the second gate flap 66 between their respective first and second switching position. In addition, sensors (not shown) which are known per se can be provided that detect the reaching of the respective end positions of the gate flaps 58, 66, i.e., the respective first switching position and the respective second switching position. The detection signals of the sensors can also be applied to the control apparatus 48 in the shown example.

[0038] Tablets 74 which are discharged through the gate 50 for different operating states of the gate 50 are shown in FIGS. 3 to 5. As can be seen in FIG. 3, the tablets 74 traverse the second discharge channel 54 when the first gate flap 58 and the second gate flap 66 are in the first switching position. If contrastingly the first gate flap 58 moves toward its second switching position as shown in FIG. 4, the stream of tablets 74 is deflected from the second discharge channel 54 into the first discharge channel 52. Only when the first gate flap 58 is located in its first switching position does the stream of tablets 74 reach the second gate flap 66. Depending on its switching position, this deflects the stream of tablets 74 into the third discharge channel 72 (see FIG. 5) or closes the access to the third discharge channel 72 so that the stream of tablets 74 can continue to flow through the second discharge channel 54.

[0039] The second discharge channel 54 can for example lead to a tablet outlet for good tablets. The third discharge channel 72 can for example lead to a tablet outlet for a sampling. The first discharge channel 52 can for example lead to a tablet outlet for bad tablets.

[0040] In FIG. 4, a tablet 76 for example is shown clamped between the first gate flap 58 and the opposite wall 64. For this reason, the first gate flap 58 cannot reach its second switching position. The lack of reaching the second switching position can be detected by the respective sensor and output to the control apparatus. This then outputs a gate malfunction which can lead to a stoppage of the rotary tablet press.

[0041] To avoid this, it is provided according to the invention that the speed of movement of the first gate flap 58 and the second gate flap 66 is slowed before the target switching position is reached during an adjustment from a home switching position to a target switching position so that any tablet 76 located in a critical region for clamping can still flow out in a timely manner before clamping occurs. The respective gate flap 58, 66 can correspondingly safely reach its target switching position, and a gate malfunction is avoided.

[0042] It can for example be provided that the first gate flap 58 and/or the second gate flap 66 is braked up to the point of stopping before reaching its target switching position. This is shown for example in FIG. 5 for the first gate flap 58. The gate flap 58 was moved starting from its first switching position toward the second switching position, and braked in the stoppage position shown in FIG. 5 before reaching the second switching position. After reaching the stoppage position and possibly after the expiration of a given stoppage period, the gate flap 58 is adjusted further toward its second switching position. This can very reliably prevent a clamping of tablets.

[0043] It can also be seen in FIGS. 2 to 5 that the second discharge channel 54 expands in width on both sides directly upstream from the region swept by the first gate flap 58 during its pivoting movement, in particular the region swept by its free end 62. The expanding sections are shown with reference numbers 80 and 82. In this context, it is discernible that the expanding section 82 is formed because an upstream constriction from a wall projection 84 terminates. The sections 80, 82 that expand stepwise in the shown example each substantially correspond in the shown example to the width of the tablets 74, 76 to be diverted by the gate 50. As shown for example in FIG. 5 with regard to the first gate flap 58, said flap is brought to a stop directly upon reaching the expanding section 80. This ensures that the gate flap 58 brought to a stoppage does not impair the remaining stream of tablets 74. In particular, the free end 62 of the first gate flap 58 basically does not project inwardly beyond the wall section 86 located directly upstream from the expanded section 80. Apart from that, the function explained in this regard is otherwise equivalent for the first gate flap 58 and the opposing expanded section 82 as well as for the second gate flap 66. There is also a section 90, 92 with an expanded width in the second discharge channel 54 located on opposing sides directly upstream from the region swept by the free end 88 of the second gate flap 66 during its pivoting movement. The expanded section 92 is formed by the end of the first gate flap 58the bottom end in FIG. 2of the constriction of the second discharge channel 54. In the same manner as explained above with reference to the first gate flap 58, the expanded sections 90, 92 also enable a slowing, or respectively a stoppage of the second gate flap 66, for example upon reaching the respective expanded section 90, 92 so that the remaining stream of tablets 74 is not impaired. The expansion 90, 92 also substantially corresponds in its width to the diameter of the tablets 74, 76 to be diverted by the gate 50.

LIST OF REFERENCE NUMBERS

[0044] 10 Die plate [0045] 12 Cavities [0046] 14 Upper punches [0047] 16 Lower punches [0048] 18 Upper control cam elements [0049] 20 Lower control cam elements [0050] 22 Filling apparatus [0051] 24 Filling chamber [0052] 26 Filling material reservoir [0053] 28 Feed section [0054] 30 Pressing apparatus [0055] 32 Upper pre-pressing roller [0056] 34 Lower pre-pressing roller [0057] 36 Upper main pressing roller [0058] 38 Lower main pressing roller [0059] 40 Ejection apparatus [0060] 42 Scraper [0061] 46 Tableting discharge [0062] 48 Control apparatus [0063] 50 Gate [0064] 52 First discharge channel [0065] 54 Second discharge channel [0066] 56 Partition wall [0067] 58 First gate flap [0068] 60 First pivot axis [0069] 62 Free end [0070] 64 Wall [0071] 66 Second gate flap [0072] 68 Second pivot axis [0073] 70 Partition wall [0074] 72 Third discharge channel [0075] 74 Tablets [0076] 76 Tablet [0077] 80 Expanded section [0078] 82 Expanded section [0079] 84 Wall projection [0080] 86 Wall section [0081] 88 Free end [0082] 90 Expanded section [0083] 92 Expanded section