ROTARY TABLET PRESS COMPRISING A TURRET AND A METHOD OF PROVIDING IMPROVED ADJUSTMENT OF PARTS OF THE ROTARY TABLET PRESS

Abstract

The rotary tablet press has a housing including a compression section (6) with a turret (10) including a die disc (40), a top punch guide (20), a bottom punch guide (30), and a plurality of punches (25, 35). The turret (10) defines an axial direction (a) and a radial direction (r), the punches being arranged at a predefined radius defining a pitch (p) of the turret. The rotary tablet press comprises a bearing assembly (50) connected to the turret (10) and providing support to at least one auxiliary component of the rotary tablet press and the bearing assembly comprises a bearing (51) and a support means (60) for the at least one auxiliary component, and the bearing (51) is positioned outside the pitch (p) of the turret in the radial direction (r).

Claims

1. A rotary tablet press comprising: a housing including a compression section, a turret including a die disc , a top punch guide, a bottom punch guide, and a plurality of punches, said turret defining an axial direction (?) and a radial direction (r), the plurality of punches being arranged at a predefined radius defining a pitch (p) of the turret, said turret being positioned in the compression section in a position of use of the rotary tablet press, and a number of auxiliary components, wherein the rotary tablet press comprises a bearing assembly connected to the turret and providing support to at least one of the number of auxiliary components of the rotary tablet press, and wherein the bearing assembly comprises a bearing and a support means for the at least one of the number of auxiliary components, and wherein the bearing is positioned outside the pitch (p) of the turret in the radial direction (r), and wherein a reference point relative to the turret is provided.

2. A rotary tablet press according to claim 1, wherein the bearing assembly provides support in the axial direction (?) and the radial direction (r) of the turret.

3. A rotary tablet press according to claim 1, wherein the bearing comprises a ball bearing, wherein the ball bearing is one or more of a four point contact ball bearing or a pre-loaded bearing.

4. A rotary tablet press according to claim 1, further comprising an anti-rotation element is provided that prevents the support means from rotating during use.

5. A rotary tablet press according to claim 1, wherein the bearing assembly further comprises a bearing housing and a support flange, the bearing housing including comprising an inner bearing housing part connected to an outwards facing circumferential of said turret, and the bearing housing comprising an outer bearing housing part connected to the support flange.

6. A rotary tablet press according to claim 5, wherein the inner bearing housing part is connected to the bottom punch guide at a stepped portion that comprises said outwards facing circumferential of the turret.

7. A rotary tablet press according to claim 1, wherein the bearing is connected to an inwards facing circumferential of said turret.

8. A rotary tablet press according to claim 7, wherein the bearing is connected to a flange depending from the bottom punch guide.

9. A rotary tablet press according to claim 1, wherein the bearing assembly is connected to the top punch guide.

10. A rotary tablet press according to claim 1, wherein the bearing assembly is connected to the die disc.

11. A rotary tablet press according to claim 1, wherein said at least one of the number of auxiliary components is attached to the support means to permit removal from the compression section of the housing with the turret without disconnecting the number of auxiliary components.

12. A rotary tablet press according to claim 11, wherein the at least one of the number of auxiliary components comprises one or more feeders of the turret.

13. A rotary tablet press according to claim 1, wherein the at least one of the number of auxiliary components comprises a cover.

14. A rotary tablet press according to claim 13, wherein the cover is made from one or more of a light-weight or transparent material.

15. A rotary tablet press according to claim 13, wherein the cover is made from one piece or a limited number of pieces.

16. A rotary tablet press according to any claim 13, wherein the cover comprises a locking means.

17. A rotary tablet press according to claim 1, further comprising a seal between the turret and the support means.

18. A method for providing adjustment of at least one auxiliary component of a rotary tablet press, the method comprising: providing the rotary tablet press with a housing including a compression section, and a rotary turret including a die disc, a top punch guide, and a bottom punch guide, said rotary turret defining an axial direction and a radial direction, providing said rotary turret in the compression section in a position of use of the rotary tablet press, providing a bearing assembly, connecting the bearing assembly to the rotary turret, connecting at least one auxiliary component to said bearing assembly, wherein the bearing assembly provides a reference point for adjusting the at least one auxiliary component with reference to the rotary turret.

19. The method of claim 18, further comprising supporting the at least one auxiliary component in the axial direction and the radial direction.

20. The method of claim 18, wherein said at least one auxiliary component is removed from the compression section of the housing with the rotary turret without disconnecting the at least one auxiliary component(s) from the rotary turret.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In the following the invention will be described in further detail by means of examples of embodiments and referring to the schematic drawings, in which

[0026] FIG. 1 shows a perspective overview of a rotary tablet press;

[0027] FIG. 2 shows a perspective view, on a larger scale, of details of a rotary tablet press in an embodiment of the invention;

[0028] FIG. 3 shows a perspective view of details of the embodiment shown in FIG. 2, seen from below;

[0029] FIG. 4 shows, on a larger scale, a sectional view through parts of the turret, the support plate and a bearing in the embodiment of FIGS. 2 and 3;

[0030] FIGS. 5 and 6 show perspective views of details of a further embodiment of a rotary tablet press according to the invention;

[0031] FIGS. 7a and 7b show schematic axial sections of further embodiments of the rotary tablet press; and

[0032] FIGS. 8 to 10 show schematic axial sections of still further embodiments of the rotary tablet press including details such as the turret, with the support plate positioned at the bottom, die disk and top of the turret, respectively.

DETAILED DESCRIPTION OF THE INVENTION AND OF PREFERRED EMBODIMENTS

[0033] Referring first to the schematic overview of FIG. 1 showing a first embodiment of a rotary tablet press generally designated 1, the rotary tablet press 1 has a press housing 2 comprising a frame 3 and an outer lining 4. The press housing 2 is composed of three sections, which are located on top of each other and are separated by means of partition walls. The lower section, designated the drive section 5, is separated from a central section, designated the compression section 6, by a bottom frame 7 of the press, and the compression section 6 is separated from an upper section, designated the accessory section 8, by a top frame 9 of the press. FIG. 1 further shows caps 21, 22 and 23 which are present to prevent excessive contamination of mechanical parts.

[0034] It is noted that only parts relevant to the present invention will be described in detail. For detailed information regarding the operation of a rotary tablet press, reference is made to the above-mentioned WO 03/020499 A1 and WO 2009/112886 A1 (Courtoy).

[0035] In a manner known per se the housing 2 accommodates a turret 10, parts of which are shown in more detail in FIGS. 2 and 3. During operation of the tablet press, the turret 10 is positioned in the compression section 6 of the housing 2, but may be removed from the compression section 6 in order to allow for instance cleaning, change-over of parts, etc. as indicated in FIG. 1.

[0036] The turret 10 comprises a top punch guide 20, a bottom punch guide 30, and a die disc 40 between the top punch guide 20 and the bottom punch guide 30. In the embodiment shown, the die disc 40 is substantially plate-shaped and has a number of bores 41 accommodating a corresponding number of dies (not shown) adapted for forming the tablets to the desired shape and size.

[0037] Referring also to the schematic view of FIG. 7, the bores 41 are arranged at a predefined radius defining a pitch p of the turret 10. The bores 41 are evenly distributed along a circumferential line near the outer border of the die disc 40, each bore 41 being arranged with its axis parallel to an axial direction ? defined by the turret and coinciding with the vertical rotational axis of the turret. The bore 41 may as shown in FIG. 7 receive a die 45. Top and bottom punches 25 and 35 are guided in corresponding guide bores formed in the top punch guide 20 and the bottom punch guide 30, respectively. The punches 25, 35 are accommodated reciprocally in the turret so that a first end of each punch is able to enter a corresponding die, or the bore itself, if no die is present, by displacement of the associated punch in its guide bore, in order to compress material in the die or bore.

[0038] A second end of each punch 25, 35 is in a well-known manner cooperating with top and bottom cams, respectively, arranged stationary in relation to the press housing in order to effect axial displacement of the punches by rotation of the turret. The cams only extend along part of the circumference of the turret, and at that circumferential position where the compression of the material in the bore or die is to be performed, top and bottom pre-compression rollers and top and bottom main compression rollers, respectively, take over the displacement of the punches. Alternatively, compression cams may be used instead of compression rollers for pre- and/or main compression.

[0039] A number of auxiliary components are provided. A list of such auxiliary components includes, but not exhaustively: a tablet chute 11 protruding from the turret 10 at an angle for conducting away compressed material in the form of tablets from the die bores; a feeder 12 extending in between the die disc 40 and the top punch guide 20, from where it provides the die disc with powder or granules; a powder inlet tube 13 extending in the vertical, i.e. axial direction of the turret, from here powder or granules enter the turret 10 and is fed to the feeder 12. Furthermore, a scraper 14a adapted to scrape off excess powder, thereby ensuring that only the desired amount of powder is present in the die disc, an extraction nozzle 14b connected to an extraction tube for extracting dust to a suction system and an ejection finger 15 are shown. Further auxiliary components, not referred to specifically in FIGS. 2 and 3, may be present as well, such as a recuperation finger and cams (not shown). Other elements may be present in the tablet press and means for controlling the tablet press according to desired settings may be provided as well.

[0040] In the embodiment shown, the single-sided rotary tablet press 1 is adapted for production of single-layer tablets. However, configurations with multiple compression stations, multilayer configurations and configurations for dry-coated tablet production are possible with several feeders, scrapers, compression rollers, ejection stations, core-intake elements etc.

[0041] The rotary tablet press 1 comprises a bearing assembly generally designated 50 connected to the turret 10 and providing support to at least one auxiliary component of the rotary tablet press in the axial direction of the turret. As will be described in further detail below, the bearing assembly comprises a bearing 51 and a support means generally designated 60 for the at least one auxiliary component. The bearing 51 is positioned outside the pitch p of the turret in the radial direction r. In the context of the present application, the term bearing assembly should encompass a structure comprising the bearing, its housing, elements needed to mount the bearing to the turret and elements needed to enable the connection of auxiliary components to the bearing. It is noted that in the case of multiple concentric rows of punches, the feature outside the pitch should be interpreted as meaning outside the pitch of the outermost row of punches.

[0042] As shown in more detail in FIG. 4, the support means 60 in one embodiment comprises an annular support flange 61.

[0043] The bearing assembly 50 provides a reference point of one or more of the auxiliary components relative to the turret in the axial direction. Also the position in the radial direction is established. In the embodiment shown in FIGS. 2 and 3, a protruding support section 62 connected to the annular support flange 61 is provided to support the feeder 12. The support section 62 also functions as an anti-rotation element that is interacting with a counterpart (not shown) connected to the press housing.

[0044] The auxiliary component or components, for instance the above-mentioned auxiliary components 11-15 are attached to the support means to permit removal from the compression section 6 of the housing 2 with the turret 10 without disconnecting the auxiliary component or components from the turret.

[0045] In the embodiment shown in FIG. 4, the bearing assembly 50 comprises a bearing 51, a bearing housing 52, 53 and a support flange 61, the bearing housing including an inner bearing housing part 52 connected to an outwards facing circumferential of the turret, and an outer bearing housing part 53 connected to the support flange 61. The inner bearing housing part 52 is connected to the lower punch guide 30 at a stepped portion 31, 32 constituting the outwards facing circumferential of the turret. The inner bearing housing part 52 is connected to the bottom punch guide 30 by means of fastening means represented by bolt 55, and the outer bearing housing part 53 to the support flange 61 by means of bolt 54. Seals 56, 58 seal off the bearing 51 itself from the surroundings. Finally, a seal 57 is provided between the turret 10 and the support means 60, protecting the bearing assembly against contamination by powder and cleaning fluids.

[0046] The bearing 51 may be any type of bearing capable of fulfilling the demands as to load-bearing capacity and accuracy. In the embodiment shown in FIG. 4, the bearing 51 is shown as a general representation of a four point contact ball bearing, preferably a pre-loaded bearing. Other types of conceivable bearings include roller bearings (taper or cylindrical),cross roller bearings, needle bearings, combined bearings and plain bearings.

[0047] Referring now to FIGS. 5 and 6, a further embodiment of the rotary tablet press will be described. In this description, only differences relative to the embodiment shown in FIGS. 2 and 3 will be described in detail, and elements having the same or analogous function carry the same reference numerals, even though slight deviations from the first embodiment may occur.

[0048] In the embodiment shown, a cover 16 is attached to a support plate 64 forming part of the support means. The cover 16 is made from a transparent material as indicated schematically in FIG. 6, and is preferentially made of a light-weight material. However, cover can also be made of opaque material and have one or several transparent parts/windows. The cover 16 is placed in connection with the support plate, sealing against the support plate by means of sealing 64a. Although not shown, locking means may be provided to ensure tight sealing between the cover and the support plate. In the embodiment shown, the cover 16 also extends across the top of the turret 10 and comprises one or more aperture(s) 16a for receiving tubing to the interior of the cover, or other elements like shaft transmission to drive the feeder wheels, sensor cables, top cams, a non-return valve communicating with the surroundings and arranged to prevent outflow from the compression chamber to the surroundings of the tablet press. A sealing can be provided to seal the gap between the cover and these elements. In case of the cover 16, it is most convenient to provide a plate-like support element as the support plate 60, whereon the cover 16 is placed. This is not necessarily an additional plate, but can be an extended support flange or even the bearing housing elongated in the radial direction. Eventually, in the embodiment shown, a sealing 24 seals between the top punch guide of the turret 10 and the cover 16.

[0049] The cover 16 can be removed from the turret and support plate as an integral piece, or as a limited number of separate cover parts. It is also an option to partially or even completely removing the cover when the turret is still inside the tablet press.

[0050] In the alternative embodiment shown in FIG. 7a, the bearing assembly 50, 60 comprises a bearing 51 connected to an inwards facing circumferential of the turret, namely to a flange 33 depending from the lower punch guide 30.

[0051] In the further alternative embodiment of FIG. 7b, the bearing 51 is attached to the bottom plane of the bottom punch guide 30 and centered by means of dowel pins 65. Other details of this embodiment correspond in substance to those of the embodiment shown in FIG. 7a.

[0052] In FIGS. 8 to 10, three different positions of the bearing assembly relative to the turret are shown.

[0053] FIG. 8 corresponds in substance to the embodiments of FIGS. 2 to 3, 4, and 5 to 6, as the bearing assembly 50, 60 is connected to the bottom punch guide 30.

[0054] In the embodiment of FIG. 9, the bearing assembly 50, 60 is connected to the die disc 40.

[0055] Finally, in the embodiment of FIG. 10, the bearing assembly 50, 60 is connected to the upper punch guide 20.

[0056] The invention is not limited to the embodiments shown and described in the above. Several combinations and modifications may be carried out without departing from the scope of the appended claims.