Abstract:
A pressure roller unit for rotary presses, especially for preparing tablets, with a frame lockable at the rotary press and with two bearing blocks, which can be adjusted at the frame and carry the pressure rollers. To absorb stronger pressing forces and to extensively relieve the press frame of the pressing forces, the frame is formed from a guide column ( 1 ), and the bearing blocks ( 20 ) are arranged at upper and lower pressure roller mounts ( 2  and  3 ), which are guided by the guide column ( 1 ) and are adjustable in relation to one another.

Description:
FIELD OF THE INVENTION 
     The present invention pertains to a pressure roller unit for rotary presses, especially for preparing tablets, with a frame lockable at the rotary press and with two bearing blocks which are adjustable at the frame and carry the pressure rollers. 
     BACKGROUND OF THE INVENTION 
     Such pressure roller units are used in rotary presses which comprise a frame, a rotor with drive, upper and lower rockers, which guide upper and lower pressure rollers, a frame housing, corner connections, and a cover plate. The forces occurring during the pressing process are directly introduced into the cover plate and the frame via the punches and the rockers and induce vibrations in these membrane-like components due to the pressing forces. These vibrations lead to considerable noise emissions. 
     A pressure roller unit of this type has been known from U.S. Pat. No. 3,891,375. In this pressure roller unit, the frame comprises upper and lower crossbeams, which are connected by vertical braces, and two columns arranged between these, on which the bearing blocks of the pressure rollers are slidable. The frame is mounted pivotably around a vertical axis in the press frame and forms a part of the press housing in the closed position. The frame may be pivoted by about 90° from a working position into the open position, in which case the drive of the pressure rollers is uncoupled and the pressure rollers are disengaged from the upper and lower punches. The bearing block for the upper pressure roller is connected to the upper crossbeam by means of an adjustable spacer. The spacer is used to set the depth of penetration of the upper punches into the dies of the die disk. The bearing block for the lower pressure roller is connected via a shaft to a hydraulic adjusting unit, which acts on the lower pressure roller for the purpose of setting the tablet thickness. The drawback is that the pressing force passes over the press frame and that the mounting of the bearing blocks for the pressure rollers at the two vertical columns and at the frame pivotable in the press frame is soft and elastic, so that the prior-art pressure roller unit can be used for weak pressing forces only. 
     SUMMARY AND OBJECTS OF THE INVENTION 
     The basic object of the present invention is therefore to improve the pressure roller unit of this type. 
     To accomplish this object, the present invention provides for the frame formed from a guide column and bearing blocks arranged at jointly adjustable upper and lower pressure roller mounts guided by the guide column. As a result, a pressure roller unit which can be used to absorb strong pressing forces is created, whose guide column can be designed as an extremely stable guide column, and the pressing force is prevented from passing over the press frame. Furthermore, the upper and lower pressure roller mounts may be adjusted not only independently from one another, but also together, in order to thus make possible the adjustment of the pressing zone in the case of the parallel adjustment of both pressure roller mounts at a fixed distance from another, or the adjustment of the web height for setting the tablet thickness in the case of the setting of the lower pressure roller mount in relation to the upper pressure roller mount. 
     In the preferred embodiment, the guide column and the pressure roller mounts have a cylindrical design and the pressure roller mounts are mounted in the guide column. Thus, this forms the housing of the pressure roller unit at the same time. 
     In another embodiment of the present invention, the upper pressure roller mount is provided with an upper adjusting drive acting on the guide column, and the lower pressure roller mount is provided with a lower adjusting drive, which is mounted in the upper pressure roller mount and acts on same. 
     Furthermore, the guide column is mounted vertically upright on a frame plate of the rotary press and can be set and locked by means of an adjusting drive. This design and arrangement of the pressure roller unit is possible, because the pressing forces of both pressure rollers are absorbed exclusively by the guide column, and this guide column can thus be arranged freely on a component standing on a massive, rigid and twisting-resistant frame plate of the rotary press. 
     The various features of the novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings: 
     FIG. 1 is a vertical sectional view taken through the pressure roller unit; 
     FIG. 2 is an enlarged vertical sectional view taken through the upper adjusting drive; 
     FIG. 3 is an enlarged vertical sectional view taken through the lower adjusting drive; 
     FIG. 4 is a vertical sectional view taken through the adjustable mounting of the pressure roller unit on a frame plate, and 
     FIG. 5 is a view of a rotary tabletting press with the pressure roller unit. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The pressure roller for rotary tabletting presses comprises a massively designed guide column  1  of cylindrical cross section, in the cylindrical interior space of which a likewise cylindrical and hollow, upper pressure roller mount  2  and a cylindrical and internally hollow, lower pressure roller mount  3  are slidably mounted, wherein the upper and lower pressure roller mounts  2 ,  3  are likewise of a massive and stable design. The adjusting drive  4  for the upper pressure roller  40  is arranged in the upper area of the guide column  1 , and the adjusting drive  5  for the lower pressure roller  50  is arranged in the middle area of the guide column  1 . The upper adjusting drive  4  is used for setting the upper pressure roller  40  and thus the depth of penetration of the upper punch  56 , on which the upper pressure roller  40  acts, and for adjusting the upper and lower pressure rollers  40  and  50 , respectively, jointly, i.e., in parallel, at a fixed distance and thus for adjusting the pressing zone. The adjusting drive  5  for the lower pressure roller  50  is used to set the tablet thickness in relation to the upper pressure roller  40 . 
     The upper adjusting drive  4  shown in FIG. 2 on a larger scale contains a gear motor  6  with a gearbox  36  and power take-off shaft  37 . The gear motor  6  is surrounded by a closing cover  42  closing off the guide column  1  in the upward direction, as well as a pot-shaped spindle  7 , which is connected to the power take-off shaft in a non-positive matter. The pot-shaped spindle  7  has external teeth  66  which mesh with the internal teeth  67  of a spindle nut  12  fixed in the cylindrical upper pressure roller mount  2 . To mount the gear motor  6  and the gearbox  36 , two disks  8 ,  9  are screwed to the upper end of the guide column  1 . The disk  9  carries the gear motor  6  and the gearbox  36 , and the outer bearing ring of a bearing  10  is clamped between the two disks  8 ,  9 , and the inner bearing ring of said bearing  10  carries the upper circumferential edge of the pot-shaped spindle  7 . The pot-shaped spindle  7  is thus freely rotatable in relation to the disks  8 ,  9  and the gearbox  36  enclosed inside. The spindle nut  12  is screwed to a flange  11 , which in turn is screwed to the top side of the cylindrical upper pressure roller mount  2 . The likewise hollow cylindrical upper pressure roller mount  2 , which is slidable in the inner cylindrical hole  81  of the guide column  1  by means of sliding elements  68 , can thus be moved vertically adjustably within the guide column  1  by actuating the gear motor  6  and in cooperation with the rotatable spindle  7  and the fixed spindle nut  12 . 
     On the side shown on the left in FIGS. 1 and 2, the upper pressure roller mount  2  has a passage opening  38 , in which the massive bearing block  20  for the upper pressure roller  40  is mounted, wherein the end of the bearing block  20 , which is the right-hand end in FIG. 1, is inserted into an inner recess  69  on the inside of the cylindrical upper pressure roller mount  2  by means of a screw  39 . In the area of the head of the screw  39 , a mounting opening  43 , which is closed by a plug  70 , is provided within the cylindrical guide column  1 . On the outer side of the guide column  1 , which is the left-hand outer side in FIG. 1, the pressure roller axle  20  carries the upper pressure roller  40  acting on the upper punch  56  with the pressure roller mount  41  comprising two angular ball bearings  71 . A sealing ring  72  cooperating with the rear side of the upper pressure roller  40  is arranged on the outside of the guide column  1  facing the upper pressure roller  40 . The pressure roller axle  20  of the upper pressure roller  40  has a hole  35  for manual adjustment in the central axis  73 . 
     The adjusting drive  5  for the lower pressure roller  50 , which is shown on a larger scale in FIG. 3, contains a gear motor  13  with gearbox  14 , which is mounted in the gearbox flange  16 , which in turn is mounted in an axially longer mounting sleeve  15 , wherein the gearbox flange  16  and the mounting sleeve  15  are tightened with screws  74  in the lower area of the upper pressure roller mount  2 . The mounting sleeve  15  dips with its outer circumference freely into the top end of the lower pressure roller mount  3 , which has a hollow cylindrical design, just as the upper pressure roller mount  2 . The drive shaft  45  of the transmission formed by the gear motor  13  and the gearbox  14  engages a spindle  18  through a clutch disk  75 , which lies on the upper bearing ring of a ball bearing  44 , and the external teeth  76  of the spindle  18  mesh with the internal teeth of a spindle nut  17  fixed in the lower pressure roller mount  3  by means of screws  46 . By actuating the gear motor  13 , the cylindrical lower pressure roller mount  3 , which is slidably mounted in the inner hole  81  of the guide column  1  by means of nonskid elements  68 , like the cylindrical upper pressure roller mount  2 , can thus be moved vertically slidably and adjustably within the guide column  1  by means of the adjusting drive  5  shown in FIG.  3 . This adjusting movement is used to adjust the web height or to set the tablet thickness in relation to the upper pressure roller  40 . FIG. 3 also shows that compression springs  19  are inserted between the upper pressure roller mount  2  and the lower pressure roller  3 . 
     The pressure roller axle  20  of lower pressure roller mount  41  is inserted under the adjusting drive  5  in a passage opening  78  in the lower pressure roller mount  3  of the pressure roller axle  20  for the lower pressure roller  50 , and the right-hand end of this pressure roller axle  20  of lower pressure roller mount  41  shown in FIG. 1 is in turn clamped by means of a screw  39  in a recess  69  on the inside of the lower pressure roller mount  3 , wherein a corresponding mounting hole  43  is closed by means of a plug  70 . The lower pressure roller  50  is also mounted on the corresponding pressure roller axle  20  by means of a pressure roller mount  41  formed by angular ball bearings  71  and is sealed by means of a sealing ring  72 . The lower pressure roller  50  cooperates with the lower punches  56 . 
     The pressure roller unit shown in FIG. 1 is mounted with its guide column  1  vertically upright on a massive base plate  29  of the rotary tabletting press and is movable by means of a horizontally operating adjusting drive  79 , which is shown on a larger scale in FIG. 4. A truncated cone-shaped mounting flange  22  is fixed within the lower end of the guide column  1  by means of three ring segments  23  distributed over the circumference and of additional ring elements  49 . A tie rod  21 , which passes through a projection  48  at the lower end of the truncated cone-shaped mounting flange  22 , is screwed into the mounting flange  22  within the central axis  73  of the guide column  1 , and the tie rod is movable within an elongated hole  47 , which is provided in the massive base plate  29  of the rotary tabletting press. The tiered  21  passes through the wedge  24  within the stop ring  26  under the base plate  29 , and the stop ring  26  is held by the T-shaped head of the tie rod  21  by means of a dome-shaped piece  80 . The wedge  24  can be loosened and tightened by means of a spindle  25 , which is located rotatably and horizontally nondisplaceably in a vertical bolt  53  at the free end, which is inserted into a vertical blind hole  52  on the underside of the base plate  29 . The spindle  25  has a spindle head  51  on its face. It is connected to a pressure piece  27  acting on the tie rod  21  via a compression spring  28 . For locking, the spindle  25  is rotated at the spindle head  51  until the projection  48  of the mounting flange  22  and the stop ring  26  at the end of the elongated hole  47 , which is the left-hand end in FIG. 4, come into contact with base plate  29 . Under the action of the compression spring  28 , the spindle  25  now presses the pressure piece  27  against the spindle  21 . The wedge  24  is displaced at the same time to the left in FIG. 4 such that the guide column  1  becomes firmly seated on the top side of the base plate  29  of the rotary tabletting press by means of the tie rod  21 . 
     To pull the pressure roller unit and thus the pressure rollers  40 ,  50  forward from the engagement area of the upper and lower punches  56  and  57 , respectively, the spindle  25  is rotated in the opposite direction by means of the spindle head  51 , the compression spring  28  is released, and the wedge  24  is moved away from the stop ring  26  by a small amount, so that the guide column  1  is released from its fixed tensioning at the base plate  29  and can be pulled to the right in FIG. 4 by continuing to actuate the spindle  25 . 
     FIG. 5 shows a view of the entire rotary tabletting press, in which the pressure roller unit comprising the guide column  1  and the upper and lower pressure rollers  40  and  50 , respectively, is placed on the base plate  29  and FIG. 5 shows that the pressing force from the rollers  40 ,  50  is transmitted through the guide column  1  to the one end of the guide column connected to the base plate  29 . The upper and lower punches  56  and  57  engage dies of the die plate  55 , not shown. The respective upper and lower pressure rollers  40  and  50  act on the respective punch heads  58  and  59  during the rotation of the die plate  55  of the rotor  30 . The rotor  30  is driven via a drive motor  54 , a toothed belt  31  and two belt pulleys  60  and  61 , as well as a tightening disk  62 . The massive base plate  29  accommodating the pressure roller  1 , the rotor  30  and the drive motor  54  is mounted on the base frame  33  of the rotary tabletting press by means of a plurality of rubber-bonded-to-metal mountings  32 , the rotary tabletting press being carried by frame legs  34  at the installation site. The rotary tabletting press also contains non-carrying frame parts  63 ,  64  and  65 , which are used to accommodate the press control and the encapsulation of the rotor  30  and of the pressure roller unit  1 . 
     While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles. 
     
       
         
               
             
               
               
               
             
           
               
                   
               
               
                 LIST OF REFERENCE NUMBERS 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                  1 
                 Guide column 
               
               
                   
                  2 
                 Upper pressure roller mount 
               
               
                   
                  3 
                 Lower pressure roller mount 
               
               
                   
                  4 
                 Adjusting drive for depth of 
               
               
                   
                   
                 penetration 
               
               
                   
                  5 
                 Adjusting drive for tablet 
               
               
                   
                   
                 thickness 
               
               
                   
                  6 
                 Gear motor 
               
               
                   
                  7 
                 Spindle (pot-shaped) 
               
               
                   
                  8, 9 
                 Disk 
               
               
                   
                 10 
                 Bearing 
               
               
                   
                 11 
                 Flange 
               
               
                   
                 12 
                 Spindle nut 
               
               
                   
                 13 
                 Gear motor 
               
               
                   
                 14 
                 Gearbox 
               
               
                   
                 15 
                 Mounting sleeve 
               
               
                   
                 16 
                 Gearbox flange 
               
               
                   
                 17 
                 Spindle nut 
               
               
                   
                 18 
                 Spindle 
               
               
                   
                 19 
                 Compression spring 
               
               
                   
                 20 
                 Pressure roller axle 
               
               
                   
                 21 
                 Tie rod 
               
               
                   
                 22 
                 Mounting flange 
               
               
                   
                 23 
                 Ring segment 
               
               
                   
                 24 
                 Wedge 
               
               
                   
                 25 
                 Spindle 
               
               
                   
                 26 
                 Stop ring 
               
               
                   
                 27 
                 Pressure piece 
               
               
                   
                 28 
                 Compression spring 
               
               
                   
                 29 
                 Base plate 
               
               
                   
                 30 
                 Rotor 
               
               
                   
                 31 
                 Toothed belt 
               
               
                   
                 32 
                 Rubber-bonded-to-metal 
               
               
                   
                   
                 mounting 
               
               
                   
                 33 
                 Base frame 
               
               
                   
                 34 
                 Frame leg 
               
               
                   
                 35 
                 Hole for manual adjustment 
               
               
                   
                 36 
                 Gearbox 
               
               
                   
                 37 
                 Drive shaft 
               
               
                   
                 38 
                 Passage opening 
               
               
                   
                 39 
                 Screw 
               
               
                   
                 40 
                 Upper pressure roller 
               
               
                   
                 41 
                 Pressure roller mount 
               
               
                   
                 42 
                 Closing cover 
               
               
                   
                 43 
                 Mounting opening 
               
               
                   
                 44 
                 Bearing 
               
               
                   
                 45 
                 Drive shaft 
               
               
                   
                 46 
                 Screw 
               
               
                   
                 47 
                 Elongated hole 
               
               
                   
                 48 
                 Projection 
               
               
                   
                 49 
                 Ring element 
               
               
                   
                 50 
                 Lower pressure roller 
               
               
                   
                 51 
                 Spindle head 
               
               
                   
                 52 
                 Hole 
               
               
                   
                 53 
                 Bolt 
               
               
                   
                 54 
                 Drive motor 
               
               
                   
                 55 
                 Die plate 
               
               
                   
                 56 
                 Upper punch 
               
               
                   
                 57 
                 Lower punch 
               
               
                   
                 58, 59 
                 Punch head 
               
               
                   
                 60, 61, 62 
                 Belt pulley 
               
               
                   
                 63, 64, 65 
                 Frame parts 
               
               
                   
                 66 
                 External teeth 
               
               
                   
                 67 
                 Internal teeth 
               
               
                   
                 68 
                 Sliding element 
               
               
                   
                 69 
                 Recess 
               
               
                   
                 70 
                 Plug 
               
               
                   
                 71 
                 Angular ball bearing 
               
               
                   
                 72 
                 Sealing ring 
               
               
                   
                 73 
                 Central axis 
               
               
                   
                 74 
                 Screw 
               
               
                   
                 75 
                 Clutch disk 
               
               
                   
                 76 
                 External teeth 
               
               
                   
                 77 
                 Internal teeth 
               
               
                   
                 78 
                 Passage opening 
               
               
                   
                 79 
                 Adjusting drive 
               
               
                   
                 80 
                 Dome-shaped piece 
               
               
                   
                 81 
                 Hole