Abstract
The invention relates to a rotary press having height-staggered ram tips for carrying out at least two pressing operations, which preferably build on one another. Furthermore, the invention relates particularly to rotary presses and methods for producing multi-layer and coating-core tablets and for pressing tablets into cups during a rotation.
Claims
1. A rotary press for carrying out at least two pressing operations during a rotation of the rotary press, said rotary press including a rotor (28), a die table (18), a top ram guide (17) for receiving top rams (10), and a bottom ram guide (19) for receiving bottom rams (11), characterized in that the top rams (10) each comprise at least two top ram tips (12, 13), wherein a first top ram tip (12) is of a length which is by a length difference (L.sub.D1) shorter than that of a second top ram tip (13), and the bottom rams (11) each comprise at least two bottom ram tips (14, 15), wherein a first bottom ram tip (14) is of a length which is by a length difference (L.sub.D2) longer than that of a second bottom ram tip (15), the die table (18) comprises first die cavities (32) which are aligned with the first top and bottom ram tips (12, 14), and comprises second die cavities (33), which are aligned with the second top and bottom ram tips (13, 15), such that a first material to be pressed (34) can be pressed in the first die cavities (32) in a first pressing operation and a second material to be pressed (35) can be pressed in the second die cavities (33) in a second pressing operation during one rotation of the rotor of the rotary press.
2. The rotary press according to the claim 1, characterized in that the extension of the first die cavities (32) and the extension of the first top and bottom ram tips (12, 14) are smaller than the extension of the second die cavities (33) and the extension of the second top and bottom ram tips (13, 15).
3. The rotary press according to claim 1, characterized in that the rotary press includes die inserts (16), the die table (18) comprises recesses (37) for the die inserts (16), and the first die cavity (32) and the second die cavity (33) are provided in a die insert (16).
4. The rotary press according to claim 1, characterized in that the rotary press includes a transport device (24), which transports the first pressed product (34) after the first pressing operation into the second die cavities (33).
5. The rotary press according to claim 4, characterized in that the transport device (24) includes a turnstile (36) or a slider, and the bottom press tool (11) can be moved after the first pressing operation to a position in which the upper end of the first bottom ram tip (14) is flush with the surface of the die table (18) and the first pressed product (34) is transported into the second die cavity (33) by turning the turnstile (36) or by the slider.
6. The rotary press according to claim 1, characterized in that the first die cavities (32) and the first top and bottom ram tips (12, 14) are arranged concentrically on an inner pitch circle, and the second die cavities (33) and the second top and bottom ram tips (13, 15) are arranged concentrically on an outer pitch circle.
7. The rotary press according to claim 1, characterized in that the rotary press is suitable for pressing tablets (1) in cups (2) and the rotary press includes a filling station (29), a first pressing station (20), a cup inserting station (22), a transport device (24), and a second pressing station (25), wherein the filling station (29) is configured to dose a powder, into the first die cavities (32), the first pressing station (20) is configured to press the powder in the first die cavities into a tablet (1) in a first pressing operation, the cup inserting station (22) is configured to position cups (2) in the second die cavities (33), the transport device (24) is configured to insert the tablet (1) into the cups (2), which are located in the second die cavities (33), and the second pressing station (25) is configured to press the tablet (1) into the cups (2) in a second pressing operation.
8. The rotary press according to claim 7, characterized in that the first pressing station (20) comprises a measuring device for determining the pressing force during the first pressing operation, and the rotary press includes an ejection station (23), which is configured to eject tablets (1) for which the pressing force deviates from a specified normal range during the pressing process.
9. The rotary press according to claim 7, characterized in that the second pressing station (25) comprises a measuring device for determining the pressing force during the second pressing operation, and the rotary press includes a sorting station (26), which is configured to direct cups (2) with pressed-in tablets (1) during the second pressing operation either to a transport path (26a) for suitable cups (2) with pressed-in tablets (1) or to a transport path (26b) for unsuitable cups (2) with pressed-in tablets (1) depending on the pressing force, if the pressing force deviates from a specified normal range.
10. The rotary press according to claim 7, characterized in that the pressing stations comprise top and bottom pressure rollers, which act on the rams (10, 11).
11. The rotary press according to claim 7, wherein the powder is a metal oxide powder.
12. A method for producing cathodes for button cells using a rotary press according to claim 1, the method comprising the following steps a) Dosing powder into first die cavities (32) by means of a filling station (29) b) Pressing the powder into tablets (1) by means of a first pressing station (20), wherein optionally the pressing force is determined c) Optionally ejecting tablets (1) for which a pressing force was determined in step c) which deviates from a normal range, d) Inserting the cups (2) into the second die cavities (33) by means of a cup inserting station (22) e) Inserting the tablet (1) into the cups (2), which are located in the second die cavities (33), by means of a transport device (24) f) Pressing the tablet (1) into the bottom of the cups (2) by means of the second pressing station (25) and the interaction of the second top ram tips (13) and second bottom ram tips (15), wherein optionally the pressing force is determined g) Ejecting the cathodes, wherein optionally the cathodes are directed to a transport path (26a) for suitable cathodes or to a transport path (26b) for unsuitable cathodes depending on the pressing force determined in step f) by means of a sorting station (26).
13. The method for producing cathodes for button cells according to claim 12, wherein the dosing powder is a metal oxide powder.
14. The method for producing cathodes for button cells according to claim 12, wherein the transport device (24) includes a turnstile (36).
15. The method for producing cathodes for button cells according to claim 12, wherein the dosing powder is a metal oxide powder and the transport device (24) includes a turnstile (36).
16. The rotary press according to claim 1 for carrying out at least three pressing operations during one rotation of the rotary press characterized in that the rotary press is suitable for producing coating-core tablets (43) and the rotary press includes a filling station (29), a first pressing station (20), a second filling station (38), a second pressing station (25), a transport device (24), a third filling station (39), and a third pressing station (40), wherein the filling station (29) is configured to dose a first powder into the first die cavities (32), the first pressing station (20) is configured to press the first powder in the first die cavities (32) into a core tablet (41) in a first pressing operation, the second filling station (38) is configured to dose a second powder into the second die cavities (33), the second pressing station (25) is configured to tamp the second powder in the second die cavities (33) in a second pressing operation, the transport device (24) is configured to insert the core tablet (41) into the second die cavities (33) onto the already tamped second powder, the third filling station (39) is configured to dose the second powder into the second die cavities (33), whereby the core tablet (41) is covered by the second powder, the third pressing station (40) is configured to press the core tablet (41) coated with the second powder in the second die cavities (33) into a coating-core tablet (43).
17. The rotary press according to claim 16, characterized in that the first pressing station (20) comprises a measuring device for determining the pressing force during the first pressing operation, and the rotary press includes an ejection station (23), which is configured to eject core tablets (41) for which the pressing force deviates from a specified normal range during the pressing process.
18. The rotary press according to claim 16, characterized in that the third pressing station (40) comprises a measuring device for determining the pressing force during the third pressing operation, and the rotary press includes a sorting station (26), which is configured to guide coating-core tablets (43) during the third pressing operation to a transport path (26a) for suitable coating-core tablets (43) or to a transport path (26b) for unsuitable coating-core tablets (43) depending on the pressing force during the third pressing operation.
19. A method for producing coating-core tablets (43) using a rotary press according to claim 1, the method comprising the following steps a) Dosing a first powder for the core of the coating-core tablet (43) into first die cavities (32) by means of a first filling station (29) b) Pressing the first powder into core tablets (41) by means of a first pressing station (20), wherein optionally the pressing force is determined c) Optionally ejecting core tablets (41) for which a pressing force was determined in step b) which deviates from a normal range d) Dosing a second powder for the coating of the coating-core tablet (43) into second die cavities (33) by means of a second filling station (38) e) Tamping the second powder by means of a second pressing station (25) f) Inserting the core tablet (41) into the tamped second powder, which is located in the second die cavities (33), by means of a transport device (24), g) Dosing the second powder into second die cavities (33) by means of a third filling station (39), such that the core tablet (41) is covered with the second powder h) Pressing the core tablet (41) coated with the second powder into a coating-core tablet (43) by means of a third pressing station (40), wherein optionally the pressing force is determined i) Ejecting the coating-core tablet (43), wherein optionally the coating-core tablets (43) are directed to a transport path (26a) for suitable coating-core tablets or to a transport path (26b) for unsuitable coating-core tablets depending on the pressing force determined in step h) by means of a sorting station (26).
20. The method for producing coating-core tablets according to claim 19, wherein the transport device (24) includes a turnstile (36).
Description
BRIEF DESCRIPTION OF THE FIGURES
(1) FIG. 1 Schematic representation of a preferred embodiment of a cathode
(2) FIG. 2 Schematic representation of a cross section of a rotor of a preferred embodiment of the rotary press for illustrating the height-staggered rams
(3) FIG. 3 Schematic representation of a side view of a preferred embodiment of the rotary press for illustrating the ejection of pressed tablets by means of the height-staggered bottom rams
(4) FIG. 4 Schematic representation of a preferred embodiment of a rotary press for producing cathodes for button cells
(5) FIG. 5 Schematic top view of a preferred embodiment of the rotary press of FIG. 4 for illustrating the successive steps for producing a cathode for button cells
(6) FIG. 6 Schematic representation of a preferred embodiment of the transport device designed as a turnstile for transferring tablets from the first die cavities to the second die cavities
(7) FIG. 7 Schematic representation of a preferred embodiment of the sorting station for ejecting and sorting the pressed cathodes
(8) FIG. 8 Schematic representation of a preferred embodiment of a rotary press for producing coating-core tablets
(9) FIG. 9 Overview of various applications for preferred embodiments of the rotary press
DETAILED DESCRIPTION OF THE FIGURES
(10) FIG. 1 shows a schematic representation of pressing tablets 1 into cups 2 like it is carried out for the production of cathodes. The bulk metal oxide tablet 1.1 has a preferably smaller diameter than the cups 2 and is inserted into the cup 2. The band height of the metal oxide tablet is reduced while its diameter increases due to the interaction of top and bottom rams (not shown). In this process, the tablet 1 is pressed flatly into the cup bottom. The flatly pressed-in metal oxide tablet 1.2 thus is in firm contact with the inner wall of the cup. Air can escape during the pressing operation, such that the flatly pressed-in metal-oxide tablet 1.2 is firmly and securely present in the cup 2.
(11) FIG. 2 shows a schematic representation of a preferred embodiment of the height-staggered rams 10 and 11. The top ram 10 is located in the top ram guide 17 and comprises a first top ram tip 12 and a second top ram tip 13. The length of the first top ram tip 12 is by a length difference L.sub.D1 shorter than the length of the second top ram tip 13. It is further preferred that the first top ram tip 12 has a smaller diameter than the second top ram tip 13. The bottom rams 11, on the other hand, are guided by means of a bottom ram guide 19 and include a first bottom ram tip 14 (not drawn in) and a second bottom ram tip 15 (not drawn in). The length of the first bottom ram tip 14 is by a length difference L.sub.D2 longer than the length of the second bottom ram tip 15. In the embodiment shown, the length differences L.sub.D1 and L.sub.D2 are identical. Furthermore, the first top and bottom ram tips 12 and 14 have an identical shape and an identical diameter. The same applies to the second top and bottom ram tips 13 and 15. The top and bottom rams 10 and 11 are aligned with the first die cavities 32 and the second die cavities 33. The size and shape of the circular die cavities 32 and 33, respectively, corresponds to the size and shape of the aligned pairs of top and bottom ram tips 12 and 14 or 13 and 15, respectively. In the embodiment shown, the die cavities are formed by openings in the die inserts 16, which are located in recesses of the die table 18.
(12) FIG. 3 shows a side view of the preferred embodiment of a rotary press, which includes height-staggered rams, according to FIG. 1. As shown in FIG. 2, the first top and bottom ram tips 12 and 14 are arranged on an inner pitch circle, while the second top and bottom ram tips 13 and 15 are guided on an outer pitch circle. The bottom ram tips 14 and 15 can be seen in the central four die inserts 16. The outer, second bottom ram tip 15 is flush with the upper edge of the die table. The inner, first bottom ram tip 14 projects beyond the upper edge of the die due to the length difference L.sub.D2. Due to the height staggering of the bottom rams, the second bottom ram tips 15 advantageously do not represent an obstacle for ejecting the tablets 1 by means of the first bottom ram tips 14.
(13) FIG. 4 and FIG. 5 show a schematic perspective view and top view of a preferred rotary press for pressing tablets in cups. The tablets preferably are metal oxide tablets for producing cathodes for button cells. The components of the rotary press are mounted onto a mounting plate 27. For a better overview, the machine housing, the machine base, and the drive system of the rotary press are not shown. The rotor 28 of the rotary press includes a top and a bottom ram guide 17 and 19, a die table 18, and top and bottom rams 10 and 11. The direction of rotation of the rotor 28 is indicated by an arrow. During the rotation of the rotor, i.e. a rotation of the rotary press, the rams rotate together with the die inserts 16 in the die table 18 through various functional assemblies or stations, which cause the production process of the cathodes. The assemblies or stations of the rotary press are described in accordance with their order of operation along the direction of rotation of the rotor 28. By means of the first filling station 29, the first powder, preferably the metal oxide powder, is filled into the first die cavities of the die inserts. As can be seen in FIG. 5, the filling station 29 for this purpose preferably includes a feed shoe with a material supply system, impellers, and a scraping device for filling and dosing the metal oxide powder into the first die cavities. After filling the first die cavities 32, the die insert 16 rotates under the first pressing station 20. In the preferred embodiment, this is a pressure roller station having a top pressure roller 30 and a bottom pressure roller (not visible). The top ram shafts 44 pass under the top pressure roller 30 during the rotation. In this way, the top rams 10 are subjected to a downward pressing force. Likewise, the bottom rams 11 are subjected to an upward pressing force, such that the first top and bottom ram tips press the powder in the first die cavities 32 into tablets 1. It is preferred that the pressing force is determined at the first pressing station 20 by means of a measuring cell. If the pressing force determined should deviate from a specified normal range, the defective tablet is ejected in the ejection station 23. The ejection station 23 preferably includes a discharge chute, and ejection is carried out by lifting the first bottom ram tips 14. After producing the tablets 1 and quality check by the electronically controlled ejection station 23, the cups 2 are inserted into the second die cavities 33. For this purpose, the cups 2 are supplied by means of a cup feeding device 21 in a transport bar of a vibration feeder and conveyor belt of the cup inserting station 22. The cup inserting station 22 preferably includes a turnstile with gripping arms, which takes over the cups 2 and transfers them in a rotational movement to the second die cavities 33. The cup inserting station 22 first separates the cups 2 for subsequent precise insertion. This allows a high cycle rate of inserting the cups 2. After inserting the cups, the tablets 1 are transferred into the cups 2 by means of the transport device 24. FIG. 6 schematically shows the operation of the preferred transport device 24. After inserting the tablet 1 into the cups 2, which are located in the second die cavities 33, the tablet 1 is pressed in by the second pressing station 25. It is preferred that the second pressing station also is a pressure roller column, and like at pressing station 20, a top pressure roller 31 and a bottom pressure roller (not shown) interact with the rams. It is preferred that the pressure rollers are adjusted such that the bottom rams 11 remain in their position nearly constantly. During the second pressing operation, the second bottom ram tip 15 therefore acts as a counterpart, and the second top ram tip 13 can press the tablet 1 uniformly and homogeneously onto the cup bottom. This effectively prevents air pockets. In the case of metal oxide tablets, the cups 2 with the finished pressed-in tablets 1 are called cathodes, which can be further processed into button cells. It is preferred that the pressing force is determined during the second pressing operation. Suitable and unsuitable cathodes are directed to different containers in a sorting station 26 by comparing the pressing force to a specified normal range. FIG. 7 showed a schematic representation of the operation of the sorting station 26.
(14) FIG. 6 shows a schematic view of a preferred transport device 24 for transferring the tablets 1 into the cups 2. The first bottom ram tips 14 are moved to a position in which the upper ends of the first bottom ram tips 14 (not drawn in) are level with the surface of the die table 18. Thus the tablets 1 are at the level of the surface of the die table 18. It is preferred that the second bottom ram tips 15 (not drawn in) have a length that is by a length difference L.sub.D2 shorter than the length of the first bottom ram tips 14, wherein L.sub.D2 is selected such that L.sub.D2 is greater than or equal to the cup height. In this position, the cups 2 lying on the second bottom ram tips 15 in the second die cavities 33 are thus located underneath the surface of the die table 18. When passing into the transport device, the tablet 1 can therefore be moved into the cups by a simple rotational movement of the preferred turnstile 36. For this purpose, the turnstile 36 comprises two radially extending arms, whose shape and spacing is adjusted to the tablet size. The rotational frequency of the turnstile 36 is adjusted to the rotational speed of the die table 18, such that the tablets 1 are inserted into the cups 2 in a precisely timed manner.
(15) FIG. 7 shows a schematic view of a preferred sorting station 26. The cups 2 with the pressed-in tablets 1, which preferably are cathodes, are preferably ejected by lifting the second bottom ram tips 15. Since the first bottom ram tips 14 are arranged on an inner pitch circle, they are located behind the cathodes in the direction of ejection. Due to the height-staggered rams, the first bottom ram tips 14 project from the surface of the die table 18 by at least the length difference L.sub.D2 and thus do not obstruct the ejection of the cathodes. The ejection movement is dependent on the pressing force which was determined when the tablets were pressed in. If the pressing force is within the specified normal range, the cathodes are suitable. If the pressing force deviates from the specified normal range, the cathodes are rated defective. Defective, unsuitable cathodes are ejected when entering the sorting station on a first transport path 26b into a rejects container (not shown). Suitable cathodes are ejected at a slight delay in a second transport path 26a of the discharge chute and placed in a container for suitable cathodes.
(16) FIG. 8 shows a schematic representation of a preferred rotary press for producing coating-core tablets. The rotor 28 of the rotary press includes a top and a bottom ram guide 17 and 19, a die table 18, and height-staggered top and bottom rams 10 and 11 (all not drawn in). The direction of rotation of the rotor 28 is indicated by an arrow. During the rotation of the rotor, i.e. a rotation of the rotary press, the rams 10 and 11 rotate together with the die inserts 16 in the die table 18 through various functional assemblies, which enable the production process of the coating-core tablets. The assemblies of the rotary press are described in accordance with the flow of the production process along the direction of rotation of the rotor 28. Die inserts 16, each including a first die cavity 32 and a second die cavity 33, are present in recesses of the die table 18. The die cavities are preferably circular in shape, wherein the first die cavity 32 has a smaller diameter than the second die cavity 33. In addition, the first die cavities 32 are present on an inner pitch circle, while the second die cavities 33 are arranged on an outer pitch circle. By means of the first filling station 29, the first powder for the core 41 is filled into the first die cavities 32 of the die inserts. The powder is then pressed into a core tablet 41 in a first pressing operation while passing through the first pressing station 20. It is preferred for this purpose that top and bottom pressure rollers interact with the top and bottom rams in the pressing station 20. In this process, it is preferred that the pressing force is determined by means of a measuring cell in the pressing station 20 and compared to a normal range. A defective tablet would be detected via the pressing force check and be guided by the individual sorting system into the reject duct of the ejection station 23. The ejection station 23 preferably includes a discharge chute, and ejection is carried out by lifting the first bottom ram tips 14. After producing the core tablets 41, a second powder for the coating of the core tablets 41 is dosed into the second die cavities onto the surface area of the second bottom ram tips 15 by means of a second filling station 38. The second powder is tamped in the second pressing station by interaction of the top pressure roller 31 and the bottom pressure roller (not shown) with the rams. This process is preferably referred to as tamping. Slight tamping of the second powder for the coating allows particularly precise positioning of the core tablet 41. A transport device 24 is used for inserting the core tablets 41 onto the already tamped coating bottom in the second die cavities 33. The preferred transport device 24, which is shown in FIG. 6, is also preferably suited for inserting the core tablets 41. After the core tablets 41 were inserted onto the coating bottom in the second die cavities 33, additional metal powder, the second powder, is dosed by means of a third filling station 39. The core tablet 41 is thus completely encompassed by the coating powder. The coating-core tablet 43 is pressed in a third pressing operation by means of the third pressing station 40 and a top pressure roller 42 and a bottom pressure roller (not shown). It is preferred that the pressing force is determined during the third pressing operation. Suitable and unsuitable coating-core tablets are directed to different containers in a sorting station 26 by comparing the pressing force to a specified normal range. It is preferred that the sorting station 26 and mode of operation shown in FIG. 7 are used for this purpose.
(17) FIG. 9 illustrates various preferred fields of application of the rotary press having height-staggered rams according to the invention. Due to the height staggering of the rams, multiple pressing operations which may optionally build on one another can be carried out during one rotation. This allows the production of complex products during one rotation. A coating-core tablet can preferably be produced as described during one rotation. Furthermore, it is preferably possible to produce a multi-layer tablet, preferably a three-layer tablet, during one rotation of a single rotary press. For the production of the illustrated multi-layer tablet, the first and second die cavities are preferably circular, wherein the diameter of the first die cavities is only slightly smaller than the diameter of the second die cavities. It is preferred that the first die cavities are located on an inner pitch circle of the die table, whereas the second die cavities are located on an outer pitch circle. The powder of the inner second layer is preferably dosed into the first die cavities by means of a first filling station and then pressed into a tablet by means of a first pressing station. A second filling station then doses the material of the third layer into the second die cavities, which is pressed by means of a second pressing station. A transport device can place the tablet which forms the second layer of the multi-layer tablet into the second die cavities onto the already tamped third layer. A third filling station and pressing station preferably allow pressing on the first layer and thus finishing the multi-layer tablet. A has been explained in detail above, it is preferably further possible to press tablets into cups or other containers by means of the staggered rams according to the invention. The staggered rams thus surprisingly present a particularly simple manner of pressing products from multiple components during one rotation. Advantageously, first pressed products such as the core in the case of a coating-core tablet, a tablet which forms the second layer of a multi-layer tablet, or a metal oxide tablet for producing cathodes can processed further in pressing operations building on the first one. But the staggered rams can also be used for producing separate products in independent pressing operations. It can for example be preferred, as illustrated, to produce tablets of a smaller diameter in the first die cavities during the first half of the rotation and to produce tablets of a larger diameter in the second die cavities during the second half of the rotation. This makes it possible to produce tablets of different weight for the pharmaceutical industry using a single tablet in the rotation. For example, a batch of 50 mg tablets can be produced on the inner pitch circle in the first die cavities, while a batch of 100 mg tablets is run on the outer pitch circle in the second die cavities. It is preferred that the same material to be pressed with the same active ingredient is used for producing these tablets of different dosages. Compared to prior art, the staggered rams thus provide clearly increased flexibility with respect to the number or complexity of the pressed products.
(18) It should be noted that various alternatives to the embodiments of the invention described can be used to execute the invention and to arrive at the solution according to the invention. Embodiments of the rotary press according to the invention and its use in the methods described are not restricted to the above preferred embodiments. Instead, a multitude of design variants is conceivable, which may deviate from the solution presented. It is the goal of the claims to define the scope of protection of the invention. The scope of protection as laid out in the claims is aimed at covering the rotary press according to the invention and preferred methods as well as equivalent embodiments thereof.
LIST OF REFERENCE SYMBOLS
(19) 1. tablet 1.1 bulk metal oxide tablet 1.2 pressed-in metal oxide tablet 2 cup 10 top ram 11 bottom ram 12 first top ram tip 13 second top ram tip 14 first bottom ram tip 15 second bottom ram tip 16 die insert 17 top ram guide 18 die table 19 bottom ram guide 20 first pressing station 21 cup feeding device 22 cup inserting station 23 ejection station for defective tablets 24 transport device 25 second pressing station 26 sorting station 26a transport path for suitable cathodes 26b transport path for unsuitable cathodes 27 mounting plate 28 rotor 29 first filling station 30 top pressure roller of the first pressing station 31 top pressure roller of the second pressing station 32 first die cavities 33 second die cavities 34 first material to be pressed/pressed product 35 second material to be pressed/pressed product 36 turnstile 37 recesses 38 second filling station 39 third filling station 40 third pressing station 41 core tablet 42 bottom pressure roller of the third pressing station 43 coating-core tablets 44 top ram shaft 45 bottom ram shaft
