WO2009101184A1

WO2009101184A1 - Tablet press machine with a turret sub assembly

Info

Publication number: WO2009101184A1
Application number: PCT/EP2009/051726
Authority: WO
Inventors: Doug Stopforth
Original assignee: Oystar Manesty
Priority date: 2008-02-14
Filing date: 2009-02-13
Publication date: 2009-08-20
Also published as: DE102008009364B4; EP2197661A1; DE102008009364A1

Abstract

The invention relates to a tablet press machine comprising a turret sub assembly (10) which is carried by a driven spindle (5) and rotates jointly with said spindle about an axis D. The turret sub assembly (10) comprises a die plate (20) in which a plurality of dies ( 22) or die carriers are arranged, an upper punch guiding plate (30) located above the die plate (20) and a lower punch guiding plate (40) located below the die plate (20). The die plate (20), upper punch guiding plate (30) and lower punch guiding plate (40) are configured as separate parts which can be fixed to one another by means of at least one fixing device (12) in such a manner that the turret sub assembly (10) can be inserted into the tablet press machine and removed there from as a one-piece coherent part.

Description

TABLET PRESS MACHINE WITH A TURRET SUB ASSEMBLY

The present invention relates to a tablet press machine with turret sub assembly according to the preamble of the main claim. In particular, the invention relates to a tablet press machine having a turret sub assembly comprising a one-piece die plate in which a plurality of dies or die carriers are located.

Numerous tablet press machines are known from the prior art. In principle, tablet press machines comprise a turret sub assembly which is almost always carried by a driven spindle and which rotates jointly with the spindle about an axis of rotation D. In this case, the turret sub assembly usually comprises a die plate in which a plurality of dies or die carriers are located. The die carriers are provided to accommodate separately formed dies therein. Upper or lower punch guiding plates are usually located respectively above and below the die plate, wherein a plurality of upper or lower punches displaceable in the direction of the axis of rotation are located, the ends whereof engage in the dies of the die plate.

During rotations of the turret sub assembly, the upper or lower punches are actuated by cams which, for example, can be connected mechanically firmly to a frame of the tablet press machine. However, the cams can also be formed as disks which are rotatably mounted on the frame of the tablet press machine.

At the present day, most of the tablet press machines in use comprise a turret sub assembly in which a plurality of separately formed dies is inserted in the die plate. As an example of this mention may be made of DE 101 59 114 B4 which discloses a rotor for a tablet press in which the die plate is configured as a separate ring. At the same time, the ring is divided into a plurality of segments which can be fastened on the lower punch guiding plate of the turret sub assembly by means of a clamping mechanism. At the same time, a plurality of holes which serve directly as dies are formed in the die plate. In the document to which reference is made, a lower liability of contamination of the die plate is mentioned as an advantage. If, for example, the tablet form or size is to be changed, the individual segments of the die plate are replaced by segments of a die plate having different dies. However, a disadvantage of the construction known here from is that the segmenting of the die plate for its part increases the liability of contamination since the powder material to be tabletted can be deposited in the joints between the segments of the die plate. The alignment effort required when changing the segments of the die plate has also proved to be high.

On the other hand, EP 1 368 181 Bl discloses a tablet press machine in which the turret sub assembly again comprises a die plate, an upper punch guiding plate located above the die plate and a lower punch guiding plate located below the die plate. The die plate, and the upper and lower punch guiding plates are formed as separate parts and no segmenting of the die plate is provided. Instead, the die plate comprises a plurality of die carriers which are provided to accommodate separately formed dies therein. In this tablet press machine, the entire turret sub assembly consisting of die plates and upper and lower punch guiding plates is designed as a mechanically coherent unit which can be removed as a whole from the tablet press machine. However, since the die plate used here is based on exchangeable dies, in the design disclosed here no particular attention has been paid to the dismountability of the turret sub assembly. If the die plate of the turret sub assembly is to be changed, a laborious dismantling of the turret sub assembly is required followed by a laborious assembly. The expenditure of time required for this prevents the tablet press machine known from this patent from being used with a die plate in which the dies are formed directly.

It is therefore the object of the present invention to provide a tablet press machine with a turret sub assembly in which a die plate formed in one piece can be simply exchanged.

This object is achieved by a tablet press machine having the features of the independent claim. A tablet press machine according to the invention comprises a turret sub assembly which is carried by a driven spindle. In this case, the spindle and the turret sub assembly rotate about a common axis D. The turret sub assembly further comprises a one-piece die plate in which a plurality of dies or die carriers is arranged, preferably regularly. A preferably disk-shaped an upper punch guiding plate is located above the die plate and a likewise preferably disk-shaped lower punch guiding plate is located below the die plate. In this case, the die plate, the upper punch guiding plate and the lower punch guiding plate are configured as separate parts which can be fixed to one another by means of at least one fixing device in such a manner that the turret sub assembly consisting of the die plate, upper punch and lower punch carriers can be inserted into the tablet press machine and removed there from as a one-piece coherent part.

According to the invention, a positioning device is provided on the turret sub assembly which, when joining together the die plate, upper punch guiding plate and lower punch guiding plate to form the turret sub assembly, determines the position of the die plate, the upper punch guiding plate and the lower punch guiding plate relative to one another in the circumferential direction. In principle, it is possible to provide a first positioning device which determines the relative position of the die plate and upper punch guiding plate with respect to one another and a second positioning device which determines the position of the die plate and the lower punch guiding plate relative to one another. In a preferred embodiment, however, the positioning device is configured so that it simultaneously determines the relative position of the die plate and upper punch guiding plate and of the die plate and lower punch guiding plate in the circumferential direction.

By providing such a positioning device, the necessary alignment effort when joining the die plate and upper punch and lower punch guiding plate to form the turret sub assembly, e.g. after exchanging the die plate, is drastically reduced. In particular, it is possible to implement the positioning device by suitable mechanical configuration so that when joining together the die plate and upper punch guiding plate or lower punch guiding plate, the correct alignment of the die plate and upper punch guiding plate or lower punch guiding plate in the circumferential direction takes place automatically. For this purpose, the positioning device can be formed, for example, by pins having guide faces inclined towards the axis of rotation D of the of the spindle which, when the pins engage in complementarily shaped recesses in a component of the turret sub assembly slightly twisted with respect to its desired position, generate a force which effects a relative movement of the die plate and upper punch guiding plate or lower punch guiding plate and thereby automatically leads to a correct alignment of said parts in the circumferential direction.

In a preferred embodiment, the positioning device not only determines the position of the die plate and the upper punch guiding plate and/or lower punch guiding plate relative to one another in the circumferential direction but rather it determines the relative position of the aforesaid parts in a perpendicular plane to the axis of rotation D of the spindle. In this way, it is not only possible to minimise the alignment effort required to produce the position of the die plate, upper punch guiding plate and/or lower punch guiding plate relative to one another in the circumferential direction with sufficient accuracy. Since the die plate, upper punch guiding plate and/or lower punch guiding plate are automatically positioned relative to one another in a plane perpendicular to the axis of rotation D of the spindle, clear advantages are obtained in regard to avoiding imbalance of the entire turret sub assembly. The effort required for re-assembly of the turret sub assembly, i.e. after exchanging the die plate can thereby be reduced dramatically.

In a preferred embodiment, the positioning unit comprises a first pin which extends from the upper side of the die plate and engages in a recess in the upper punch guiding plate or conversely.

In a further preferred embodiment, the positioning unit of the tablet press machine according to the invention comprises a second pin which extends from the underside of the die plate and engages in a recess in the lower punch guiding plate or conversely. In a particularly preferred embodiment, both the first and the second pins are part of a one-piece positioning device which can be inserted in particular into a recess in the die plate. The previously mentioned self-centring properties of the positioning device can be realised, for example by a corresponding configuration of the outer peripheral surfaces of a, for example, slightly conical positioning pin.

In a further preferred further development of the tablet press machine according to the invention, the turret sub assembly further comprises an assembly unit comprising a collar part which is provided to be placed at the top on the upper punch guiding plate. In this case, the collar part forms a central through hole. Furthermore the assembly unit comprises a central axis bolt which is guided through the central through hole in the collar part. The central axis bolt is used to fix the turret sub assembly mechanically on the spindle in the operating state of the tablet press machine. In a particularly preferred embodiment, the central axis bolt of the assembly unit is connected undetachably to the collar part. Furthermore, the assembly unit can be configured so that the central axis bolt has at least two usage positions. In a locking position the central axis bolt fixes the turret sub assembly on the spindle of the tablet press machine. In a removal position, on the other hand, the turret sub assembly can be inserted into the tablet press machine or removed there from as a one-piece part by means of a removal device acting, for example, on the central axis bolt. For this purpose, the central axis bolt preferably forms a mechanical point of application for the removal device.

According to a further aspect of the present invention, an alternative turret sub assembly according to the invention comprises a die plate in which a plurality of dies or die carriers are disposed, an upper punch guiding plate located above the die plate and a lower punch guiding plate located below the die plate. The die plate, upper punch guiding plate and lower punch guiding plate are formed as separate parts which can be fixed to one another by means of at least one fixing device in such a manner that the turret sub assembly can be inserted into the tablet press machine and removed there from as a one-piece coherent part. The turret sub assembly further comprises an assembly unit comprising a collar part which is provided to be placed at the top on the upper punch guiding plate. In this case, the collar part forms a central through hole. Furthermore, the assembly unit comprises a central axis bolt which is guided through the central through hole in the collar part. The central axis bolt is used to mechanically fix the turret sub assembly on the spindle in the operating state of the tablet press machine. In the preferred embodiment, the upper punch guiding plate can be combined to form a mechanical unit with the assembly unit, e.g. using suitable mechanical connecting means such as screws or a quick-closure system. These connecting means are preferably independent of the first fixing device.

Since the upper punch guiding plate and the assembly unit are combined to form a separate mechanical unit, by releasing the first fixing device, it is possible to dismantle the turret sub assembly into two assemblies - an upper and a lower one. By raising the upper assembly comprising the assembly unit and the upper punch guiding plate, the die plate is exposed for access or exchange.

In a further development of this preferred embodiment, a positioning device is also provided on the turret sub assembly which determines the position of the die plate, the upper punch guiding plate and/or the lower punch guiding plate relative to one another in the circumferential direction when joining together the die plate, the upper punching guiding plate and the lower punch guiding plate to for the turret sub assembly.

All the further configurational features described hereinafter can be provided as desired on both of the alternative turret subassemblies described hereinbefore.

In a further preferred embodiment of the aforesaid turret sub assembly, a tensioning device is provided on the central axis bolt which is configured to apply a pretension to the central axis bolt in the locking position and thereby lock it in the locking position. The introduction of such a pretension in the central axis bolt has particular advantages when the central axis bolt is screwed to the spindle of the tablet press machine. Optimum strength of the screw connection can then be achieved by introducing a pretension into the central axis bolt. At the same time, the tensioning device in particular makes it possible to achieve the required torque of a central axis bolt screwed to the spindle without the need to use large tools whereby sufficiently high torques can be applied directly to the central axis bolt. For example, the central axis bolt can form a flange on which a plurality of tensioning screws is preferably arranged equidistantly. Since these tensioning screws can be fitted with significantly smaller thread than the central axis bolt itself and a plurality of tensioning screws can be provided, application of a relatively small torque to the plurality of tensioning screws is sufficient to introduce a sufficient stress into the central axis bolts. In this way, the ready-to-operate state of the turret sub assembly on the spindle of the tablet press machine can be produced by screwing the central axis bolt the spindle in a first step by hand. The required pretension is then introduced into the central axis bolt by applying a sufficient torque to the plurality of tensioning screws. This can optionally take place using a very simple tool.

In a further preferred embodiment of the assembly unit, a thrust bearing is located between the central axis bolt and the collar part which allows a relative rotary movement of the central axis bolt and the collar part in the removal position of the central axis bolt. In this way, relative alignment of the turret sub assembly and spindle in the circumferential direction can be simplified appreciably when inserting the turret sub assembly into the tablet press machine. In particular, the required actuating forces can be minimised.

The turret sub assembly of the tablet press machine according to the invention preferably comprises a mechanical connecting means whereby at least the die plate, the upper punch guiding plate and the lower punch guiding plate are connected to form a mechanical unit. This can comprise, for example, one or more bolts which grip through the aforesaid components of the turret sub assembly and join them together. The mechanical connecting means is preferably also provided however to connect the collar part of the turret sub assembly to the die plate, the upper punch guiding plate and the lower punch guiding plate to form a mechanical unit.

Further advantages are obtained if, in addition to the aforementioned collar part, the assembly unit further comprises a pressure plate which is placed at the top on the collar part. In this case, the pressure plate cooperates with the mechanical connecting means in such a manner that the force exerted by the mechanical connecting means on the collar part is made uniform. At the same time, the pressure plate can in particular be configured as annular and form passages for a plurality of bolts.

It is known from the prior art that the punches guided in the upper punch guiding plate and lower punch guiding plates are actuated by cams during a rotation of the entire turret sub assembly which are mechanically fixed in a suitable manner on the tablet press machine, for example on a frame of the tablet press machines so that they do not follow the rotation of the spindle and turret sub assembly connected therewith. At the same time, these cams can be configured for example as fixed mimics in the form of a correspondingly contoured disk. Alternatively, however, it is also possible to use rotatably mounted disks as cams whose axis of rotation is oriented perpendicular to the axis of rotation D of the spindle. However, all these aforesaid structures have in common that the cam carrier is always mechanically connected to the tablet press machine and not to the turret sub assembly so that when the turret sub assembly is removed from the tablet press machine, the cam carrier usually remains in the tablet press machine. In the machine according to the invention, provision is now made to provide a cam carrier on the turret sub assembly itself, forming a mechanical unit with the turret sub assembly so that the cam carrier can be removed together with the turret sub assembly from the tablet press machine. At the same time, the cam carrier is rotatably disposed on the turret sub assembly so that by means of suitable measures the rotary movement of the turret sub assembly can be decoupled from the cam carrier. Rather the cam carrier can be firmly connected, for example, to a fixed frame in which the driven spindle is rotatably mounted. As a result of the rotational mounting of the cam carrier on the turret sub assembly, the turret sub assembly can turn relative to the fixed cam carrier in the ready- to-operate state of the tablet press machine.

Since the cam carrier is mechanically joined to the turret sub assembly, the removal of the turret sub assembly from the tablet press machine is substantially simplified. Furthermore, the effort involved in aligning the cams relative to the punches of the press when reinserting the turret sub assembly in the tablet press machine is substantially reduced. It is particularly preferable if the cam carrier receives the cams for controlling the lower punch but the cam carrier can also be provided for receiving cams which actuate the upper punches of the tablet press machine.

In a preferred further development of the tablet press machine according to the invention, in addition to the cam carrier on the turret sub assembly, this further comprises a second positioning device which determines the relative position of the cam carrier and the tablet press machine in general, but in particular of the frame of the tablet press machine in the circumferential direction when inserting the turret sub assembly into the tablet press machine. In particular, the second positioning device can be configured such that insertion of the turret sub assembly into the tablet press machine is only possible in a position predefined by the second positioning device. In addition, the second conditioning device can be configured such that when inserting the turret sub assembly into the tablet press machine, a torque is exerted on the turret sub assembly, in particular its cam carrier if the cam carrier is not correctly aligned relative to the tablet press machine, in particular to the frame of the tablet press machine.

Finally, the tablet press machine can also comprise a removal device whereby the turret sub assembly can be inserted as a one-piece coherent part into the tablet press machine and removed there from. At the same time, the removal device can be arranged in particular on a fixed frame of the press machine in which in particular the driven spindle of the tablet press machine is rotatably mounted. Further advantages and features of the tablet press machine according to the invention are obtained from the dependent claims and exemplary embodiments discussed hereinafter which are explained in detail with reference to the drawings. In the figures:

Fig. 1 : is a sectional view of a turret sub assembly of a tablet press machine according to the invention,

Fig. 2: is a sectional view of the turret sub assembly from Fig. 1 when releasing the fixing device of the turret sub assembly,

Fig. 3: is a sectional view of the turret sub assembly from Fig. 1 with the upper punch guiding plate raised,

Fig. 4: is a sectional view of the turret sub assembly from Fig. 3 with the die plate removed,

Fig. 5: is a sectional view showing a plurality of die plates and

Fig. 6: is a sectional view of the further developed turret sub assembly during removal from the tablet press machine.

Figure 1 is a schematic sectional view of a turret sub assembly 10 of a tablet press machine according to the invention placed on a driven spindle 5 of the tablet press machine. For reasons of clarity, apart from the turret sub assembly 10 and the spindle 5, no other parts of the tablet press machine according to the invention are shown since the features important to the invention are almost completely related to the turret sub assembly 10 of the tablet press machine. The applicant reserves the right to optionally strive for separate protection for a turret sub assembly 10 of a tablet press machine.

The turret sub assembly 10 of the tablet press machine according to the invention comprises a die plate 20 which is configured as annular. A plurality of dies 22 are formed in the die plate 20 in the form of through holes extending in the direction of the axis of rotation D of the spindle 5 of the tablet press machine. Typical tablet press machines have fifty or more dies 22 or recesses for separately formed dies 22 which are arranged equidistantly on the die plate 20. During the production of tablets with the tablet press machine according to the invention the powder material to be tabletted is usually supplied to the dies 22 in the die plate 20 from above and compressed by upper punches or lower punches displaceable in the direction of the axis of rotation D of the spindle, which are actuated by means of suitable cams during a rotation of the turret sub assembly 10 of the tablet press machine and is then ejected.

In addition to the die plate 20, the turret sub assembly 10 of the tablet press machine according to the invention comprises an upper punch guiding plate 30 located there above and a lower punch guiding plate 40 located below the die plate 20. The upper punch guiding plate 30 comprises a plurality of holes 32 which likewise extend in the direction of the axis of rotation D of the spindle 5. At the same time, the number of holes 32 corresponds to the number of dies 22 in the die plate 20. Furthermore, the holes 32 are aligned to the dies 22 of the die plate 20. The holes 32 in the upper punch guiding plate 30 are provided to receive upper punches not shown in Fig. 1 which enter into engagement with the dies 22 during the pressing process. Similarly, through holes 42 are formed in the lower punch guiding plate 40 which are again oriented in the direction of the axis of rotation D in the spindle 5 of the tablet press machine according to the invention. Here also the number and the arrangement of the holes 42 is oriented to the number and arrangement of the dies 22 in the die plate 20.

The lower punch guiding plate 40 forms a sleeve section on the underside. The driven spindle 5 of the tablet press machine according to the invention forms a complementarily shaped hub section 8 on which the lower punch guiding plate 40 with its sleeve section 46 is placed. At the same time, the hub section 8 and sleeve section 46 are fabricated to be complementary in their shape and precision in such a manner that when the turret sub assembly 10 is placed on the spindle 10, a sufficiently good running of the turret sub assembly 10 is obtained even when the turret sub assembly 10 was raised repeatedly from the spindle 5 and placed thereon. In particular the sleeve section 46 and particularly the hub section 8 can be configured such that self-centring of the lower punch guiding plate 40 takes place when placing on the spindle 5 of the tablet press machine.

At the top, the lower punch guiding plate 40 forms an annular collar section 44 which is matched with regard to its dimensions to the inner circumference 26 of the central recess formed in the die plate 20. This matching should be carried out in such a manner that when the die plate 20 is placed on the lower punch guiding plate 40, whereby the collar section 44 enters into engagement with the recess 24, adequate running of the lower punch guiding plate 40 with the die plate 20 about the axis of the spindle 5 is ensured even when the die plate 20 was repeatedly raised from the lower punch guiding plate 40 and placed thereon again.

An upper punch guiding plate 30 is placed at the top on the die plate 20, again forming a collar section 34 at its lower end which is shaped complementarily to the central recess of the annular die plate 20. When the upper punch guiding plate 30 is placed on top on the die plate 20, the collar section 34 comes to rest with its outer circumferential surface against the inner circumference 26 of the central recess of the die plate 20. Here also, the dimensions of the inner circumference 26 of the die plate 20 and the outer circumference of the collar section 34 of the upper punch guiding plate 30 are matched to one another in such a way that when the upper punch guiding plate 30 is placed in the die plate 20, sufficiently good running of the subunit of the turret sub assembly 10 comprising the lower punch guiding plate 40, the upper punch guiding plate 30 and the die plate 20 is achieved.

Of elementary importance for failsafe operation of the tablet press machine according to the invention is a very exact positioning of the holes 32 of the upper punch guiding plate relative to the dies 22 in the die plate 20, likewise the holes 42 in the lower punch guiding plate 40. As will be explained in more detail hereinafter, the tablet press machine according to the invention is provided to allow the die plate 20 to be changed in the simplest possible way by partially dismantling the turret sub assembly 10. It is therefore of essential importance to ensure a highly accurate relative alignment of die plate 20, upper punch guiding plate 30 and lower punch guiding plate 40 when exchanging the die plate 20. For this purpose, a first positioning device 14 is provided on the turret sub assembly 10 according to the invention, which in the exemplary embodiment shown consists of a first pin 16 and a second pin 18. Both the first pin 16 and also the second pin 18 are screwed into a recess 24 formed in the die plate so that the first pin 16 is raised from the upper side of the die plate 20 and the second pin 18 is raised from the underside of the die plate 20. At the same time recesses not designated in detail are formed in the upper punch guiding plate 30 and in the lower punch guiding plate 40, which are matched in their shaping to the first pin 16 or the second pin 18. The relative matching of pins and complementary recess is in such a manner that when the die plate 20 is placed on the lower punch guiding plate 40 and the first positioning device 14 has engaged, the correct relative angular position of the die plate 20 and lower punch guiding plate 40 is ensured. In a particularly preferred embodiment the second pin 18 is configured so that certain angular errors are automatically compensated when placing the die plate 20 on the lower punch guiding plate 40. That is, if the die plate 20 and the lower punch guiding plate are in an incorrect angular position, a torque is exerted on the die plate 20 which automatically produces the correct angular position between the die plate 20 and the lower punch guiding plate 40.

Also, the upper punch guiding plate 30 can only be placed on the die plate 20 when the first pin 16 and the complementarily formed recess in the upper punch guiding plate 30 are brought into congruence. Here also, a certain incorrect angular position between the upper punch guiding plate 30 and the die plate 20 can also be automatically corrected by a suitable configuration of the first positioning device 14, in particular by a suitable shaping of the cylindrical outer surface of the first pin 16. By providing the first positioning device 14 on the die plate 20, which in the exemplary embodiment shown consists of first pin 16 and a second pin 18, which engage in complementarily shaped recesses on the upper punch guiding plate 30 and the lower punch guiding plate 40, sufficiently accurate position of the upper punch guiding plate 30, die plate 20 and lower punch guiding plate 40 in the circumferential direction can be ensured even in the non-screwed state of the entire turret sub assembly 10. As has already been mentioned, the interplay of the collar sections 34 or 44 on the upper punch guiding plate 30 or the lower punch guiding plate 40 with the inner circumference 26 of the central recess of the die plate 20 can also ensure the relative positioning of said three components in a plane perpendicular to the axis of rotation D of the spindle 5 so that even during repeated dismantling and assembly of the turret sub assembly 10 according to the invention, sufficiently good running of the turret sub assembly 10 is ensured without expensive alignment measures being required to produce running.

The die plate 20, the upper punch guiding plate 30 and the lower punch guiding plate 40 are joined to form a mechanical unit which can be removed from the tablet machine by using an assembly unit 50 which is placed on top on the upper punch guiding plate 30. The assembly unit 50 comprises a collar part 52 which is placed on the top on the upper punch guiding plate 30 and its shaping is matched to the shaping of the upper punch guiding plate 30. Here also the relative shaping of the upper punch guiding plate 40 and the collar part 52 is selected so that sufficiently accurate centring of the collar part 52 on the upper punch guiding plate 30 is automatically obtained when the collar part 52 is placed on the upper punch guiding plate 30 and engages positively in its central recess. The collar part 52 has a central through hole 53 whose longitudinal axis coincides with the axis of rotation D of the spindle 5. A multipart central axis bolt 54 is inserted in this through hole 53, forming a flange 58 at its upper end and a threaded section 55 at its lower end. The threaded section 55 is provided for screwing into a threaded recess 6 of the spindle 5 whose longitudinal axis in turn coincides with the axis of rotation D of the spindle 5. When the central axis bolt 54 has been screwed sufficiently far into the threaded recess 6 of the spindle 5, its upper-side flange 58 comes to abut against the upper side of the collar part 52. Since the central axis bolt 54 is subjected to a sufficiently large torque, the entire turret sub assembly 10 is fixed on the spindle 5 of the tablet press machine so that the turret sub assembly 10 is ready to operate. In the turret sub assembly 10 which can be seen from Fig. 1, it is possible to produce the required torque of the central axis bolt 54 by directly applying a suitable torque to the bolt head. Alternatively, it is possible to use the tensioning device 59 disposed in the flange of the central axis bolt 54, which in the exemplary embodiment shown consists of a plurality of screws which are arranged equidistantly in the flange 58 and are supported on the upper side of the collar part 52. Thus, for example, six or eight equidistant screws can be provided in the flange 58 which can be tightened by hand by the operating staff. By this means a pretension in the central axis bolt 54 can be built up with a minimum expenditure of force, which is easily sufficient to secure the central axis bolt 54 in the threaded recess 6 of the spindle 5.

In order to combine the turret sub assembly 10 to form a mechanical unit, in the present exemplary embodiment a fixing device 12 is provided in the form of a plurality of bolts which grip through through-holes in the collar part 52, the upper punch guiding plate 30 and the die plate 20. At the same time, the through-holes are oriented along the axis of rotation D of the spindle 5. The through bolts engage in threaded holes in the lower punch guiding plate 40 whose longitudinal axes are again oriented parallel to the spindle axis D. Only one bolt is visible in the sectional view according to Fig. 1 but a plurality of bolts are in fact provided, disposed equidistantly along the circumference of the turret sub assembly 10. In a preferred embodiment at least three bolts are used, preferably five or more bolts. In order to ensure a uniform introduction of force into the collar part 52 of the turret sub assembly 10, a pressure plate 57 is located between the upper side of the collar part 52 and the heads of the bolts 12, which makes the force introduced into the collar part 52 by the bolt heads uniform.

Figure 1 shows the central axis bolt 54 in its locking position in which the central axis bolt 54 fixes the turret sub assembly 10 on the spindle 5. It can be clearly seen that the threaded section 55 of the central axis bolt 54 engages in the threaded section 6 of the spindle 5. It can further be identified that in the lower section of the central axis bolt 54, this is surrounded on the outside by a sleeve 56 which is supported on a shoulder formed on the stem of the central axis bolt 54. At the top of the sleeve 56, a thrust bearing 51 is located between this and the underside of the collar part 52, the function whereof will become clearer from the following figures.

Figure 2 shows the process of dismantling the turret sub assembly (10) from Fig. 1, where the turret sub assembly 10 remains with its lower punch guiding plate 40 on the spindle 5 during dismantling for the purpose of removing the die plate 20. In order to be able to dismantle the mechanical unit of the turret sub assembly 10, the bolts forming the fixing device 12 are loosened. Here Fig. 2 shows as an example only the removal of only one central axis bolt although it was previously mentioned that preferably at least three, but better five or seven bolts are provided. By removing the bolts, the mechanical unit of collar part 52, upper punch guiding plate 30, die plate 20 and lower punch guiding plate 40 is released so that the turret sub assembly 10 can then be dismantled.

In the first step the central axis bolt 54 is released from the spindle 5. For this purpose the screws of the tensioning device 59 are released so that the central axis bolt 54 is relieved of stress. Without any introduced pretension, the central axis bolt 54 can the be unscrewed by hand from the threaded recess 6 of the spindle and then brought from its locking position which can be seen from Fig. 1 into its removal position shown in Fig. 2. In the removal position of the central axis bolt 54, the thrust bearing 51 located at the top of the sleeve 56 comes to abut against the underside of the collar part 52.

Particular advantages are obtained if further connecting means are provided whereby the upper punch guiding plate 30 can be combined with assembly unit 50 to form a mechanical unit. These connecting means are preferably independent of the first fixing device 12 which serves to join the upper punch guiding plate 30, the die plate 20 and the lower punch guiding plate 40 to form a common mechanical unit. By combining the upper punch guiding plate 30 and the assembly unit 50 to form a separate mechanical unit, it is possible, by releasing the first fixing device 12, to dismantle the turret sub assembly 10 into two assemblies, one upper and one lower, as shown in Fig. 3. By raising the upper assembly comprising the assembly group 50 and the upper punch guiding plate 30, the die plate 20 is exposed for access. Since the fixing device 12 of the turret sub assembly 10 was already removed before dismantling the turret sub assembly 10 into the upper and the lower assembly, in the arrangement shown in Fig. 3 the die plate 20 rests only loosely on the lower punch guiding plate 40. Thus no further fixing devices need to be released to remove the die plate 20. In this way, the die plate 20 can be exchanged very simply without the entire turret sub assembly 10 needing to be removed from the tablet press machine.

Figure 3 now shows the next dismantling step of the turret sub assembly 10 which is initiated by raising the central axis bolt 54 in the direction of the axis of rotation D of the spindle 5. Since the collar part 52 is undetachably connected to the central axis bolt 54, the complete assembly unit 50 is raised. The upper punch guiding plate 30 is firmly connected to the collar part 52 of the assembly unit 50 by an additional screw connection which cannot be seen from the figures. Thus, when the central axis bolt 54 is moved upwards, the turret sub assembly 10 is dismantled into two parts, i.e. an upper and a lower assembly so that the die plate 20 is accessible for removal. So that the central axis bolt 54 can be raised in the direction of the axis of rotation D, the central axis bolt 54 has an application point 70 for a removal device at its upper end which is not shown in the figures for reasons of clarity. Such a removal device can be arranged in particular on a fixed frame of a tablet press machine, for example, it can be configured as a crane-like element. Such a removal device is preferably mechanically actuated and can be controlled remotely by a user, where the raised upper assembly which can be seen in Fig. 3 can be locked in any position desired by the user.

Figure 4 finally shows that in the position of the upper assembly of the turret sub assembly 10 which can be seen in Fig. 3, the die plate 20 can be removed, for example, by hand by the user. Depending on the type of die plate 20 used, the die plate 20 can then be replaced by another die plate in which, for example, the integrated dies 22 have a different size and/or shape. Instead of a die plate 20 with integrated dies 22, it is also possible to use a die plate 20 in which recesses are provided into which separately formed dies can be inserted, as is the case for example, with the die 20 shown bottommost in Fig. 5. The two upper die plates 20 which can be seen in Fig. 5 differ in that the integrated dies 22 are differently configured in their shape 20. It can be seen clearly from Fig. 5 that all the die plates 20 have a recess 24 which is provided to accommodate therein the first and second pins 16 and 18 of the first positioning device 14. Furthermore, all the die plates 20 have through holes 28 through which the bolts forming the fixing device 18 of the turret sub assembly 10 can be guided to screw the turret sub assembly 10.

In addition to the variability of the die plates 20 used with regard to shape and size of the dies 22 which can be seen from Fig. 5, in the tablet press machine according to the invention it is also possible to use various materials for the die plates 20. This makes it possible to adapt the tablet press machine to the special intended usage. For example, die plates in an anti-corrosion design e.g. made of stainless steel or die plates having specially configured surfaces suitable for food use can be produced, for example, by coating the die plate with PTFE or similar.

A particular simplification in the production of die plates 20 is obtained if the die plate 20 is provided with standardised, for example, cylindrical recesses for the insertion of individually shaped dies 22. These dies 22 can then be configured so that, when individualising the die plate 20, they are inserted in the recesses provided there, for example, are pressed in and remain there. That is, scope for exchanging of the dies 22 need not be provided. Such a die plate 20 can be produced with relatively little effort since cylindrical recesses can be produced simply by machine in the die plate 20. However, as a result of significantly smaller size, individually configured matrices can be produced substantially more easily be machine compared with the incorporation of such individually configured recesses directly in the die plate 20. In principle, however, one-piece die plates 20 of all kinds can be used with the turret sub assembly 10 according to the invention, in particular die plates 20 with separately configured exchangeable dies 20 as are widely used in the prior art.

Particular advantages are obtained if the die plate 20 is not exchanged manually in the dismantled state of the turret sub assembly 10 (see Fig. 4) but a separate lifting device for the die plate 20 is provided on the tablet press machine according to the invention. Such a lifting device can in turn be connected mechanically to a fixed component of the tablet press machine, for example to its frame. The lifting device is provided to raise the die plate 20 from the lower punch guiding plate 40. Optionally it is further provided to move the die plate 20 raised from the lower punch guiding plate 40 in the lateral direction, for example, to place it on a transporting device standing next to the tablet press machine.

It can now be seen from Fig. 6 how a complete turret sub assembly 10 according to the invention of a tablet press machine according to the invention is raised from the spindle 5 of the tablet press machine to be completely exchanged. After releasing the central axis bolt 54, a lifting device (not shown in Fig. 6) is located at its point of application 70 which, for example, can be located fixedly on a frame of the tablet press machine. The central axis bolt 54 is then brought by means of the lifting device from its locking position into the removal position, i.e. the thrust bearing 51 comes to abut against the collar part 52. The entire one-piece cohesive turret sub assembly 10 is then raised from the spindle 5. By suitably configuring the lifting device, in particular by mounting the same in a rail system, the turret sub assembly 10 can be raised not only from the spindle but rather it can also be displaced horizontally in the raised state, for example to be transported from the frame of the tablet press machine into a separate transport device.

In the turret sub assembly 10 which can be seen from Fig. 6, which comprises a further development of the turret sub assembly 10 known from the preceding figures, a cam carrier 60 is mechanically fixed to the turret sub assembly 10 on the underside of the lower punch guiding plate 40 so that this can be removed from the tablet press machine together with the turret sub assembly 10. As a result, time-consuming adjustment of the cam carrier 60 relative to the lower punch guiding plate 40 and the lower punches guided there is eliminated after maintenance work on the turret sub assembly 10 and reinsertion of the turret sub assembly 10 in the tablet press machine.

Since the cam carrier 60 remains fixed during operation of the tablet press machine, i.e. the turret sub assembly 10 turns relative to the cam carrier 60, the mechanical connection between the cam carrier 60 and the turret sub assembly 10 is made by means of an angular contact bearing 62 which is inserted between the lower end of the lower punch guiding plate 40 and a bearing flange 66 on which the cam carrier 60 is located. The angular contact bearing 62 has a load bearing capacity both in the axial and in the radial direction. This can, for example, be an angular ball bearing or a tapered roller bearing.

After inserting the turret sub assembly 10 in the tablet press machine, the cam carrier 60 is fixed mechanically to a fixed component of the tablet press machine, for example, on a frame. At the same time, a second positioning unit 64 is preferably provided between the aforesaid mechanical components of the tablet press machine and the cam carrier 60, which ensures that the cam carrier 60 can only be arranged in a predefined position relative to the fixed components of the tablet press machine. It is again hereby possible to fit this second positioning device 64 with self- aligning properties as has already been discussed for the example of the first positioning unit 14. In particular, the second positioning unit 64 can operate according to the spring-groove principle, i.e. based on form closure.

Finally a third positioning unit 9 can be provided on the spindle 5 of the tablet press machine and the turret sub assembly 10, which ensures that the turret sub assembly 10 can only be set in a defined angular position on the hub section 8 of the spindle 5. This can also operate on the spring- groove principle. In particular, the hub section 8 can have a cross-section which is not round but can be formed, for example, as polygonal, for example, in the form of a hexagonal or octagonal column section. It is also possible to flatten an inherently circular cross-section of the hub section 8 at one point and to provide the inner recess of the coupling disk 48 located under the lower punch guiding plate 40 with a complementary shaping. In the exemplary embodiment which can be seen from Fig. 6, however, the positioning device designated by 9 is configured in the form of a spring- groove connection.

Claims

1. A tablet press machine comprising a turret sub assembly (10) which is carried by a driven spindle (5) and rotates jointly with said spindle about an axis D, wherein the turret sub assembly (10) comprises the following :

a) a one-piece ring-like die plate (20) in which a plurality of dies (22) or die carriers are arranged, b) an upper punch guiding plate (30) located above the die plate (20), c) a lower punch guiding plate (40) located below the die plate (20),

wherein

d) the die plate (20), upper punch guiding plate (30) and lower punch guiding plate (40) are configured as separate parts which can be fixed to one another by means of at least one fixing device (12) in such a manner that the turret sub assembly (10) can be inserted into the tablet press machine and removed there from as a one-piece coherent part, e) the turret sub assembly (10) further comprises an assembly unit (50) comprising : i) a collar part (52) which is provided to be placed at the top on the upper punch guiding plate (30), wherein the collar part (52) as a central through hole (53), ii) a central axis bolt (54) which is guided through the central through hole (53) wherein the central axis bolt (54) is used to fix the turret sub assembly (10) mechanically on the spindle (5) in the operating state of the tablet press machine. f) fixing devices are provided whereby the upper punch guiding plate (30) can be combined to form a mechanical unit with the assembly unit (50) so that the turret sub assembly (10) can be dismantled into an upper and a lower assembly by releasing the first fixing means (12).

2. The tablet press machine according to claim 1, characterised in that a positioning device (14) is provided on the turret sub assembly (10) which, when joining together the die plate (20), upper punch guiding plate (30) and lower punch guiding plate (40) to form the turret sub assembly (10), determines the position of the die plate (20), the upper punch guiding plate (30) and/or the lower punch guiding plate (40) relative to one another in the circumferential direction.

3. The tablet press machine according to claim 2, characterised in that the positioning device (14) comprises a) a first pin (16) which extends from the upper side of the die plate (20) and engages in a recess in the upper punch guiding plate (30) or conversely and b) a second pin (18) which extends from the underside of the die plate (20) and engages in a recess in the lower punch guiding plate (40) or conversely.

4. The tablet press machine according to claim 3, characterised in that the first and the second pins (16, 18) are part of a one-piece positioning device.

5. The tablet press machine according to claim 4, characterised in that the positioning device pin is inserted into a recess (24) in the die plate (20).

6. The tablet press machine according to claim 1, characterised in that the central axis bolt (54) is connected undetachably to the collar part (54).

7. The tablet press machine according to claim 1, characterised in that the central axis bolt (54) has at least two usage positions: a) a locking position in which the central axis bolt (54) fixes the turret sub assembly (10) on the spindle (5), b) a removal position in which the turret sub assembly (10) can be inserted into the tablet press machine or removed there from as a one-piece coherent part by means of a removal device acting on the central axis bolt (54).

8. The tablet press machine according to claim 1, characterised in that the central axis bolt (54) forms a defined mechanical point of application for a removal device (70).

9. The tablet press machine according to claim 1, characterised in that a tensioning device (59) is provided on the central axis bolt (54), which is configured to apply a pretension to the central axis bolt (54) in the locking position.

10. The tablet press machine according to claim 1, characterised in that the tensioning device (59) comprises a plurality of tensioning screws which are arranged in a flange (58) formed on the central axis bolt.

11. The tablet press machine according to claim 1, characterised in that a thrust bearing (51) is located between the central axis bolt (54) and the collar part (52) which allows a relative rotary movement of the central axis bolt (54) and the collar part (52) in the removal position of the central axis bolt (54).

12. The tablet press machine according to claim 1, characterised in that the fixing device (12) further connects the collar part (52) to the die plate (20), the upper punch guiding plate (80) and the lower punch guiding plate (40) to form a mechanical unit.

13. The tablet press machine according to claim 1, characterised in that the assembly unit (50) further comprises a pressure plate (57) which is placed at the top on the collar part (52) and cooperates with the fixing device (12) in such a manner that the force exerted by the fixing device (12) on the collar part (52) is made uniform.

14. The tablet press machine according to claim 1, characterised in that the turret sub assembly (10) comprises a cam carrier (60) which a) forms a mechanical unit with the turret sub assembly (10) and b) is rotatably disposed on the turret sub assembly (10).

15. The tablet press machine according to claim 14, characterised in that a) this further comprises a fixed frame in which the driven spindle (5) is rotatably mounted and b) the cam carrier (60) is mechanically fixed on the frame when the tablet press machine is ready for operation.

16. The tablet press machine according to claim 15, characterised in that this further comprises a second positioning device (64) which determines the position of the cam carrier (60) and the frame relative to one another in the circumferential direction when inserting the turret sub assembly (10) into the tablet press machine.

17. The tablet press machine according to claim 1, characterised in that this further comprises a removal device whereby the turret sub assembly (10) can be inserted as a one-piece coherent part into the tablet press machine and removed there from.

18. The tablet press machine according to claim 17, characterised in that this further comprises a fixed frame in which the driven spindle is rotatably mounted and on which the removal device is disposed.