Abstract:
The invention relates to a rotary tableting press comprising a rotor, at least one filling station and at least one pressure station as well as lower and upper ram guides. The rotary tableting press has a modular design, such that individual modules are arranged so they can be removed and/or converted within the rotary tableting press for retooling the rotary tableting press from two-layer operation to single-layer operation or vice-versa.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims priority of and incorporates by reference German patent application no. 10 2008 020 759.4 filed Apr. 18, 2008. 
     BACKGROUND 
     Rotary tableting presses are sufficiently well known. They usually comprise a rotor having a female mold table with a number of female molds arranged on a circumferential line. An upper ram and a lower ram are assigned to each female mold and are guided by guide cams. A material to be compressed can be added to the female molds through at least one filling device. The upper ram and lower ram are guided over a filling station, a metering station, a prepressure station and a main pressure station. 
     Rotary tableting presses with which multilayer tablets, e.g., two-layer tablets, can be produced are also known. Two filling stations, two metering stations and two pressure stations are arranged around the circumference of the rotor. 
     Rotary tableting presses for laboratory operation in particular, which can be retooled from a single-layer operation to a two-layer operation, are also known. These require relatively complex retooling work, namely placement of a second filling spout and adaptation of the first pressure station, the metering unit cams and the filling cams. 
     SUMMARY 
     An embodiment of the invention provides a rotary tableting press of the generic type, which will be characterized by a simple and variable design. 
     It is advantageously possible to retool a rotary tableting press rapidly and in a versatile manner because the rotary tableting press has a modular design, with individual modules being arranged so they can be removed and/or converted for retooling of the rotary tableting press from two-layer operation to single-layer operation or vice-versa. The rotary tableting press can thus be used in a variety of ways, in particular as a laboratory press, and may thus be adapted quickly to different desired parameters. This pertains to the replacement of individual components as well as quick retooling from single-layer operation to two-layer operation and/or vice-versa. 
     In a preferred embodiment of the invention, a first filling device and a second filling device are provided, with the second filling device being removable. This makes it advantageously possible that by removing the second filling device, e.g., by dismantling or by pivoting it into a non-use position, conversion of the 
     tableting press from a two-layer operation to a single-layer operation can take place very rapidly and in particular also without the use of tools. 
     Furthermore, in a preferred embodiment of the invention, the first filling device can be equipped with an enlarged filling spout—in single-layer operation with the rotary tableting press. This advantageously makes it possible to operate the rotor at a higher rotational speed during single-layer operation without interfering with reliable filling of the female molds. 
     In addition, in another preferred embodiment of the invention, a lower pressure roll of a second pressure station in two-layer operation takes on a metering function for filling the female molds in single-layer operation. This advantageously permits effectively support for retooling of the tableting press from two-layer operation to single-layer operation while at the same time allowing multifunctional use of certain components, i.e., for both two-layer operation and single-layer operation. 
     Furthermore, in a preferred embodiment of the invention, the upper ram guide comprises multiple segments, each at least partially interchangeable with at least one other segment having a different cam characteristic. Owing to this segmentation of the ram guide, retooling from two-layer operation to single-layer operation and/or vice-versa can be implemented easily. Depending on which operating modes are to be implemented in operation, the corresponding segments are used for guiding the upper ram. The longer filling distance may be supported in a single-layer mode in this way. 
     In another preferred embodiment of the invention, the rotary tableting press comprises drive adapters which are optionally operatively connectable to drive shafts for driving filling devices and/or parts of filling devices. Remodeling of the filling zone from two-layer operation to single-layer operation and/or vice-versa can be supported easily in this way. In particular, no complex assembly work may be conducted. The available drive adapters are optionally either coupled to the corresponding drive shafts or not. 
     In addition, in a preferred embodiment of the invention, the rotor can be pivoted out of a press interior of the rotary tableting press. It is advantageously possible in this way to either replace the entire rotor or to replace the segments of the ram guides on the rotor itself, for example, and/or to adapt the upper ram and/or lower ram according to the desired parameters of the tablets to be pressed. In addition, maintenance and/or cleaning jobs can easily be performed on the rotor and/or on the interior of the press. 
     Furthermore, in a preferred embodiment of the invention, the rotor comprises a receptacle for a support arm, whereby the support arm is pivotably arranged with a guide pillar of the rotary tableting press, where a lifting mechanism is preferably integrated into the support arm for lowering and/or raising the rotor. This advantageously permits dismantling and/or installation of the motor without the use of any additional external equipment and/or tools. 
     The present invention thus relates to a rotary tableting press that can be used universally, in particular a modular design laboratory press equipped for replacement of a complete rotor with only a few manipulations or for retooling the rotor and the necessary peripherals from a two-layer operation to a single-layer operation and vice-versa. 
     Essential to the invention here is, first of all, the simple and uncomplicated operation of retooling from two-layer operation to single-layer operation. This requires only the removal of the top pressure roll for pressing on the first layer—in two-layer operation—and the cam segments of the upper ram adjacent to the top pressure roll in two-layer operation. These cam segments are replaced for a cam segment having a straight guide for the upper ram. Furthermore, the filling devices for the first layer and the second layer are removed and/or refunctionalized. It is thus possible to easily use the metering unit of the filling station for the first layer in two-layer operation simultaneously with filling of the female molds in single-layer operation. It is thus possible in single-layer operation to lengthen the filling zone easily by lengthening the filling cam in this metering. Replacement of the metering unit is not necessary. The bottom pressure roll for pressing the first layer assumes the function of a metering unit and therefore need not be dismantled or retooled. A longer filling zone for female molds is likewise possible by arranging an additional stirrer blade of a filling spout for single-layer operation, so that there may be an increase in the input speed/working speed of the rotor. Retooling of the laboratory press from two-layer operation to single-layer operation and/or vice-versa can thus be accomplished within the shortest possible amount of time, as needed. Complex breakdown and/or dismantling and assembly jobs are not necessary here. The few coordinated replacement parts can easily be positioned, primarily even without the use of tools. 
     Another aspect of the present invention is the replaceability of the complete rotor of the rotary tableting press without complex dismantling work. To do so, the rotor is pivoted laterally out of its operating position. This means that the rotor is not raised but instead remains in its elevated position. In this way, pivoting of the pressure rolls and dismantling of the guide cam for the rams and the rams themselves can be omitted. It is necessary only to remove the filling cam because in this area the lower rams engaging therein would stand in the way of pivoting the rotor out laterally. 
     In its operating position, the rotor is connected in a nonpositive manner to the drive and/or the counter bearing on its drive shaft ends by mechanically acting connecting elements, e.g., connecting elements that are pneumatically or hydraulically operable so that accurate and reproducible positioning of the rotor is possible. For dismantling, the rotor is connected to a support arm and is pivoted outward about a column of the laboratory press fixedly mounted on the frame, as stated, without any change in height. After being pivoted outward, the rotor may then be placed on a rotor wagon or the like by means of a lowering device, e.g., mechanically, hydraulically or pneumatically. Replacement of the rotor, e.g., for repairs and/or maintenance purposes or for cleaning purposes or the like, is thus readily possible in a simple manner. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The basic principle of the invention is illustrated on the basis of the following figures. They show: 
         FIG. 1  a schematic view from above of a rotary tableting press in two-layer operation; 
         FIG. 2  a schematic view from above of a rotary tableting press in single-layer operation; 
         FIG. 3  a schematic perspective view of the tableting press in two-layer operation; 
         FIG. 4  a schematic perspective view of the tableting press in single-layer operation; 
         FIG. 5  a comparison of the cams for two-layer operation and single-layer operation and 
         FIGS. 6 to 8  schematic perspective views of the tableting press, showing the peripherals that can be pivoted and/or dismantled. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows a highly schematic view from above of a rotary tableting press for production of two-layer tablets. The tableting press is labeled as  10  on the whole. The tableting press  10  comprises a rotor  12 , the one female mold table  14  with female molds arranged therein (not shown here) on a circumferential line. Upper rams and lower rams (also not shown) is assigned to each female mold. The tableting press  10  comprises, in this order, a first filling device  16 , a first pressure station  18 , a second filling device  20 , a second pressure station  22  and a main pressure station  24  as well as an ejector  26 , as seen in the circumferential direction. A medium, in particular powder to be pressed for a first layer of a tablet to be pressed is supplied via the first feed mechanism  16 ′. This first layer is prepressed via the first pressure station  18 . Next, the medium to be pressed, in particular another powder, is applied to the prepressed first layer, via the second filling device  20 . Next, via the second prepressure station  22 , the tablet is pressed, now comprising two layers. The main pressure station  24  performs the final pressing of the two-layer tablet and the finished pressed two-layer tablets are sent by the ejector  26  to a collecting container or the like. 
       FIG. 2  shows the tableting press  10  in another highly schematic diagram in the retooling variant for a single-layer operation. The same parts as in  FIG. 1  are provided with the same reference numerals and will not be explained further here. 
     It is clear that the second filling device  20  here is removed and/or shifted out of the operative area of the rotor  12 . Likewise the upper pressure roll of the first pressure station  18  is removed. The first feed mechanism  16 ′ is either retained or is equipped with a larger filling spout, as shown here. This permits filling of the female molds on a larger portion of the circumference of the partial circle of the female mold table  14 . The lower pressure roll of the first pressure station  18  here takes over the metering function for control of the lower ram for metered feed of a specific quantity into the female mold, in accordance with general practice. 
     It is clear from the schematic diagrams in  FIGS. 1 and 2  that it is possible to retool the tableting press  10  from two-layer operation (diagrammed in  FIG. 1 ) to single-layer operation (diagrammed in  FIG. 2 ) in only a few retooling steps. This retooling can be performed very rapidly because no complex assembly work is required. 
       FIG. 3  shows a schematic perspective view of the tableting press  10  in the functional state “two-layer operation.” The first feed mechanism  16 ′, the top pressure roll  28  and the bottom pressure roll  30  of the first pressure station  18  and the second filling device  20  are shown. 
     Furthermore, the rotor  12  with the female mold table  14  is visible. The rotor  12  also comprises a lower ram guide  32  and an upper ram guide  34 . The lower ram and the upper ram are displaced by guide cams in their position relative to the female mold table in an essentially known manner. The metering, pressing and ejection of tablets can be controlled in this way. The upper ram cam  36  is diagrammed schematically in  FIG. 3 , comprising different segments. A segment  38 , a segment  40  and a segment  42  can be discerned. The segment  38  is arranged above the feed mechanism  16 ′, where the upper ram is guided essentially in a certain starting position. The segment  40  by which the upper ram is guided into the prepressure position is arranged upstream from the pressure roll  28 . The segment  42  guides the upper ram connected to the pressure roll  28  out of the prepressure position into the filling position according to the arrangement of the second filling device  20 . This is essentially known. 
       FIG. 4  shows the tablet press  10  in a schematic perspective view in its operating state of “single-layer operation.” The same parts are again provided with the same reference numerals and are not explained further. It is clear that the top pressure roll  28  and the segments  40  and  42  of the upper ram guide  36  have been removed. The segments  40  and  42  have been replaced by a new segment  44 , so that the upper ram is also guided in the area of the current segment  44  into a filling position, i.e., above the female molds. 
       FIG. 4  also illustrates that the second filling device  20  has been removed. A drive shaft  46  of the second filling device  20  ( FIG. 3 ) has been released and placed in a new position, as illustrated in  FIG. 4 . The first feed mechanism  16  is replaced with a feed mechanism  16 ′, of which only the stirrer blades  48  of a corresponding filling spout are shown here for illustration. The drive shaft  46  now serves to drive the second stirrer blade  48 ′, while the drive shaft  46 ′ of the first feed mechanism  16  ( FIG. 3 ) remains and now serves to drive the first stirrer blade  48 . The first feed mechanism  16  is more or less retained and is supplemented by the second stirrer blade  48 ′. Corresponding drive adapters  47  and/or  47 ′ are provided in a base plate  11 , being operatively connected and/or connectable to the drive shafts  46  and/or  46 ′. The lower pressure roll  30  of the first pressure station  18  ( FIG. 1  and/or  FIG. 3 ) now takes up the metering function to trigger the lower ram via the partial circle of the feed mechanism  16 ′. It is clear that a longer filling zone is easily created in this way during single-layer operation, so that reliable filling of all female molds is possible, even at high rotational speeds. 
     All the other components of the tableting press  10  remain unchanged and are functional in both two-layer operation and single-layer operation. 
       FIG. 5  shows schematically the developed view of the rotor  12  of the tableting press  10 . The main pressure station  24  with the upper main pressure roll  50  and the lower main pressure roll  52  can be seen. Furthermore, the first prepressure and/or initial pressure station  18  and the second prepressure and/or initial pressure station  22  are also shown. The first prepressure station  18  has the upper pressure roll  28  and the lower pressure roll  30 . The second prepressure station  22  has the upper pressure roll  54  and the lower pressure roll  56 . This also shows the developed view of the upper ram cam  60  and/or the lower ram cam  62 . 
     As already explained with reference to the preceding figures, first the female molds are filled upstream from the first pressure station  18 , the first layer is prepressed in the pressure station  18 , the female molds are filled upstream from the second pressure station  22 , the second layer is prepressed in the pressure station  22  and the main pressing takes place in the main pressure station  24 . Downstream from the main pressure station  24 , the completely pressed tablet is ejected, indicated here with an arrow  64 . 
     In single-layer operation, the top pressure roll  28  of the first pressure station  18  is removed and the segments  40  and  42  of the upper ram guide  60  are replaced by segment  44 . The top pressure roll  30  now acts in the function of a metering roll. 
       FIG. 6  shows a schematic view of the tableting press  10 , illustrating that the rotor  12  can be pivoted completely out of the press interior  20 . The rotor  12  is mounted on a support arm  72 , which is connected by an articulated joint to a guide pillar  74  of the tableting press  10 . The rotor  12  is pivoted out in its horizontal plane of the press interior  70  into the position shown here by a simple pivoting motion. This can be accomplished without dismantling work on the rotor  12 . The pressure rolls (the first upper prepressure roll is visible here, for example) and the ram guides, the individual cam segments and the rams themselves on the rotor  12  can still be pivoted out without having to be dismantled first. When the rotor  12  has been pivoted outward, it can be set down by means of a lifting mechanism integrated into the support arm  72 , e.g., pneumatically on a rotor wagon or the like (not shown here). It is important that the rotor  12  here can be pivoted out of the press interior  70  without raising or lowering it. This means that the rotor remains essentially in its horizontal plane. There is a drive coupling to a drive machine of the tableting press  10  and/or a counter bearing is provided via the respective end faces  76  and/or  78  of the rotor  12  on corresponding counterparts for a nonpositive assembly. 
       FIGS. 7 and 8  show the tableting press  10  again schematically, illustrating which parts must be removed and/or pivoted in order for the rotor  12  to be pivotable horizontally out of the press interior as shown in  FIG. 6 . 
       FIG. 7  illustrates how the first feed mechanism  16 ′ and the second filling device  20  as well as the drive shaft  46 ′ are removed here. The filling cam is also removed. 
     These parts are removed by releasing the corresponding quick-snap connections or the like without the use of tools. 
       FIG. 8  illustrates how the parts remaining on the tableting press  10 , namely the guide elements and/or holding elements for the feed mechanism  16 ′ and/or the filling device  20  (need not be pivoted) are pivoted out of the area of the rotor  12 . Due to the dismantled parts, as shown in  FIG. 7 , and the pivoted parts, as shown in  FIG. 8 , it is readily possible to pivot the rotor  12  out of the press interior  70 , as illustrated in  FIG. 6 . This allows simple handling of the tableting press  10 , in particular for cleaning purposes, repair purposes and/or replacement of the ram cams and/or female molds on the rotor  12 . No complex dismantling work is required. 
     LIST OF REFERENCE NUMERALS 
     
         
           10  Tableting press 
           11  Base plate 
           12  Rotor 
           14  Female mold table 
           16  First filling device 
           16 ′Feed mechanism 
           18  First pressure station 
           20  Second filling device 
           22  Second pressure station 
           24  Main pressure station 
           26  Ejector 
           28  Top pressure roll 
           30  Bottom pressure roll 
           32  Lower ram guide 
           34  Upper ram guide 
           36  Upper ram cam 
           38  Segment 
           40  Segment 
           42  Segment 
           44  Segment 
           46  Drive shaft 
           46 ′ Drive shaft 
           47  Drive adapter 
           47 ′ Drive adapter 
           48  Stirrer blade 
           50  Top main pressure roll 
           52  Bottom main pressure roll 
           54  Top pressure roll 
           56  Bottom pressure roll 
           60  Upper ram cam 
           62  Lower ram cam 
           70  Press interior 
           72  Support arm 
           74  Guide pillar 
           76  End face 
           78  End face