FORM 2
THE PATENTS ACT, 1970 (39 of 1970)
As amended by the Patents (Amendment) Act, 2005
& The Patents Rules, 2003
As amended by the Patents (Amendment) Rules, 2006
COMPLETE SPECIFICATION (See section 10 and rule 13)
TITLE OF THE INVENTION
A rotary tablet making machine
APPLICANTS
Sci-tech Centre, Plot No 7 Prabhat Nagar, Jogeshwari West, Mumbai 400 102, Maharashtra, India and Pam Pharmaceuticals and Allied Machinery Company Pvt Ltd, 127, Kandivli Industrial Estate, Kandivli (West), Mumbai 400 067; Maharashtra. India, both Indian Companies
INVENTORS
Singh Jasjit of Sci-tech Centre, Plot No 7 Prabhat Nagar, Jogeshwari West, Mumbai 400 102, Maharashtra, India, a British national and Mehta Jagdish Shantilal and Lad Deepan Gunvant, both of Pam Pharmaceuticals and Allied Machinery Company Pvt Ltd, 127, Kandivli Industrial Estate, Kandivli (West), Mumbai 400 067, Maharashtra, India, both Indian nationals
PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the nature of this invention and the manner in which it is to be performed :

FIELD OF THE INVENTION
This invention relates to a rotary tablet making machine.
BACKGROUND OF THE INVENTION
A rotary tablet making machine includes a turret disposed for rotation about a vertical axis and adapted to describe cyclic intermittent rotary motion around a filling station, precompression station, compression station, ejection station and discharge station. The turret comprises a lower turret element and an upper turret element and a die table sandwiched between the lower and upper turret elements. The die table comprises a plurality of dies each located in a die retaining socket formed in the die table at the circumference thereof. The die sockets are formed at the circumference of the die table in radially spaced apart relationship at the same pitch circle diameter namely the diameter passing through the centre of all the sockets. The dies are held in position in the die sockets with locking screws tightened against the dies laterally from the outer circumference of the die table. The die sockets are circular and the dies each comprises a circular body corresponding to the circular sockets and an open ended tablet forming hole formed in the circular body matching with the geometry or shape of the tablets to be formed in the tablet making machine. Each of the dies is associated with a lower punch up and down movably held in the lower turret element and an upper punch up and down movably held in the upper turret element. Each of the lower punches and upper punches comprises a head. The tablet forming hole in each of the dies and the respective lower punch and upper punch are disposed along the same centre line. Each of the lower punch heads and the corresponding upper punch heads have a shape or geometry corresponding to the geometry or shape of the tablets to be made in the tablet making machine. The punch heads of a pair of lower

and upper punches are disposed adapted to enter into and move away from the tablet forming hole of the respective die.
During operation of the machine, tableting material is fed into the tablet forming holes in the dies at the filling station. The tableting material in the tablet forming holes in the dies is precompressed at the precompression station by advancing the lower and upper punch heads into the respective tablet forming holes in the dies. At the compression station, the tableting material in the die forming holes are compressed to the required size and shape by further advancing the lower and upper punch heads into the respective tablet forming holes in the dies. The tablets are ejected or pushed out of the tablet forming holes in the dies by advancing the lower punch heads into the tablet forming holes of the respective dies at the ejection station. At the discharge station, the tablets are scrapped down from the die table into a chute and collected from the chute.
As the dies and the die retaining sockets are circular, the surface area of the dies and sockets increases and the number of dies that can be accommodated in a given pitch circle diameter is reduced. Therefore, productivity is reduced. Further each time tablets of different shapes are to be made, it is necessary to replace the dies with dies having die forming holes of corresponding shapes. Because of the circularity of the die retaining sockets and dies, each time of replacement of the dies, it becomes necessary to carefully orient the tablet forming holes in the dies with the respective lower and upper punch heads. This is convenient and cumbersome to carry out and is also time consuming. As a result of this also productivity is reduced.

OBJECTS OF THE INVENTION
An object of the invention is to provide a rotary tablet making machine which is
simple in construction and easy to manufacture and economical.
Another object of the invention is to provide a rotary tablet making machine which increases productivity.
Another object of the invention is to provide a rotary tablet making machine which eliminates the need for alignment of the tablet forming holes in the dies with the respective lower and upper punch heads.
Another object of the invention is to provide a turret of a rotary tablet making machine, which turret is simple in construction, easy to manufacture and economical.
Another object of the invention is to provide a turret of a rotary tablet making machine, which turret increases productivity.
Another object of the invention is to provide a turret of a rotary tablet making machine, which turret eliminates the need for alignment of the tablet forming holes in the dies of the turret with the respective lower and upper punch heads of the machine.
Another object of the invention is to provide a turret of a rotary tablet making machine, which turret can be easily retrofitted in a conventional rotary tablet making machine.

DETAILED DESCRIPTION OF THE INVENTION
According to the invention there is provided a rotary tablet making machine including a turret disposed for rotation about a vertical axis and adapted to describe cyclic intermittent rotary motion around a filling station, precompression station. compression station, ejection station and discharge station, the said turret comprising a lower turret element and an upper turret element and die table sandwiched between the lower turret element and upper turret element, the die table comprising a plurality of die retaining sockets provided at the circumference thereof in radially spaced apart relationship describing a common pitch circle diameter and a plurality of dies each located in each of the die retaining sockets, each of the dies having an open ended tablet forming hole formed therein corresponding to the shape of the tablets to be made in the said machine, the dies being held in the die retaining sockets in position by locking screws tightened against the dies laterally from the outer circumference of the die table, each of the dies being associated with a lower punch up and down movably held in the lower punch element and an upper punch up and down movabty held in the upper turret element, each of the lower punch and corresponding upper punch having a plunger head corresponding to the shape of the tablets to be made in the said machine and adapted to enter into and move away from the respective tablet forming hole from the bottom and the top respectively of the tablet forming hole, wherein each of the die retaining sockets and each of the dies comprises a pair of parallel sidewalls, the parallel sidewalls of each of the dies being adapted to abut against the corresponding parallel sidewalls of each of the die retaining sockets.

According to the invention there is also provided a turret of a rotary tablet making machine comprising a lower turret element and an upper turret element and die table sandwiched between the lower turret element and upper turret element, the die table comprising a plurality of die retaining sockets provided at the circumference thereof in radially spaced apart relationship describing a common pitch circle diameter and a plurality of dies each located in each of the die retaining sockets, each of the dies having an open ended tablet forming hole formed therein corresponding to the shape of the tablets to be made in the said machine, the dies being held in the die retaining sockets in position by locking screws tightened against the dies laterally from the outer circumference of the die table, each of the dies being associated with a lower punch up and down movably held in the lower punch element and an upper punch up and down movably held in the upper turret element, each of the lower punch and corresponding upper punch having a plunger head corresponding to the shape of the tablets to be made in the said machine and adapted to enter into and move away from the respective tablet forming hole from the bottom and the top respectively of the tablet forming hole, wherein each of the die retaining sockets and each of the dies comprises a pair of parallel sidewalls, the parallel sidewalls of each of the dies being adapted to abut against the corresponding parallel sidewalls of each of the die retaining sockets.
The following is a detailed description of the invention with reference to the accompanying drawings, in which
Fig 1 is a plan view of the turret of a rotary tablet making machine according to an embodiment of the invention;

Fig 2 is an enlarged view of the portion marked X in Fig l;
Fig 3 is an isometric view of a die retaining socket of the turret of Fig 1;
Fig 4 is an isometric view of a die of the turret of Fig 1; and
Fig 5 is a partial crosssectional view of the turret of Fig 1,
As illustrated in Figs 1 to 5 of the accompanying drawings, the rotary tablet making machine 1 includes a turret 2 disposed for rotation about a vertical axis 3. The turret comprises a lower turret element 4 and an upper turret element 5 and a die table 6 sandwiched between the lower turret element and upper turret element. The die table comprises a plurality of die retaining sockets 7 provided at the circumference thereof in radially spaced apart relationship describing a common pitch circle diameter D. Each of the die retaining sockets comprises a pair of parallel sidewalls 7a, 7b and curved end walls 7c. 7d. The die table also comprises a plurality of dies 8 each having a pair of parallel sidewalls 8a, 8b and curved end walls 8c and 8d corresponding to the parallel sidewalls and curved end walls of each of the die retaining sockets. Each of the dies js Jocated in each of the die retaining sockets with the paralle sidewalls of the dies abutting against the parallel sidewalls of the die retaining sockets and the curved end walls of the dies abutting against the curved end walls of the die retaining sockets. The pitch circle diameter of the die retaining sockets is common to the pitch circle diameter of the dies. Each of the dies comprises an open ended tablet forming hole 9 corresponding to the shape or geometry of the tablets to be formed in the tablet

making machine. The dies are retained in position in the die retaining sockets by locking screws 10 tightened open slots 11 at the sides of the dies laterally from the outer circumference of the die table. Each of the dies is associated with a lower punch 12 up and down movably held in the lower turret element and an upper punch 13 up and down movably held in the upper turret element. The lower punch and upper punch each has a punch head 12a and 13a respectively aligned with the punch forming hole in each of the dies. The punch heads 12a and 13a have a geometry corresponding to the shape of the tablets to be formed in the machine. The punch heads 12a and 13a associated with each of the dies are disposed adapted to enter the tablet forming holes and move away from the tablet forming holes in the dies from the bottom and top of the tablet forming holes respectively. The machine works in known manner.
In a conventional die table there were 37 die retaining sockets and corresponding number of dies with a pitch circle diameter of 540 mm. Each die diameter and depth were 38.1 mm and 23.9 mm, respectively. According to the invention it was possible to have in a die table 46 die retaining sockets and corresponding number of dies with the same pitch circle diameter of 540 mm. Each die diameter and depth were the same namely 38.1 mm (with across flat 31 mm) and 23.9 mm, respectively. According to the invention there was thus 19.6% increase in the die retaining sockets and dies in the die table correspondingly increasing productivity by about 20%.
As a pair of the sidewalls of each of the die retaining sockets and each of the dies are parallel, the surface area of the dies and die retaining sockets at the parallel sides and hence the space between adjacent die retaining sockets and dies is considerably

reduced and it is possible to accommodate larger and more number of dies in a given pitch circle diameter in the die table. As a result, the number of tablets made in each cycle of operation of the machine is increased and productivity is increased. As a pair of sidewalls of the die retaining sockets and dies are parallel, the construction of the dies and die retaining sockets and hence that of the die table is simplified and rendered easy. Material cost is reduced and the turret is economical. Further the dies will always be seated in the die retaining sockets against the parallel sides and the die forming holes in the dies will always be oriented with respect to the punch heads of the lower and upper punches. Therefore, each time dies are replaced to make tablets of different shapes it is not necessary to orient the tablet forming holes in the dies with respect to the punch heads of the lower and upper punches. As a result, location of the dies in the die retaining sockets in the die table is easy and convenient and requires reduced time and productivity is increased also because of this reduction in time. The turret can be easily retrofitted in a conventional (existing) rotary tablet making machine to achieve the advantages of the invention. It is, however. understood that it is not necessary to have the endwalls of the die retaining sockets and dies curved. The endwalls of the die retaining sockets and dies also can be parallel or of other shapes.

We claim :
1) A rotary tablet making machine including a turret disposed for rotation about a vertical axis and adapted to describe cyclic intermittent rotary motion around a filling station, precompression station, compression station, ejection station and discharge station, the said turret comprising a lowei turret element and an upper turret element and die table sandwiched between the lower turret element and upper turret element, the die table comprising a plurality of die retaining sockets provided at the circumference thereof in radially spaced apart relationship describing a common pitch circle diameter and a plurality of dies each located in each of the die retaining sockets, each of the dies having an open ended tablet forming hole formed therein corresponding to the shape of the tablets to be made in the said machine, the dies being held in the die retaining sockets in position by locking screws tightened against the dies laterally from the outer circumference of the die table, each of the dies being associated with a lower punch up and down movably held in the lower punch element and an upper punch up and down movably held in the upper turret element. each of the lower punch and corresponding upper punch having a plunger head corresponding to the shape of the tablets to be made in the said machine and adapted to enter into and move away from the respective tablet forming hole from the bottom and the top respectively of the tablet forming hole, wherein each of the die retaining sockets and each of the dies comprises a pair of parallel sidewalls, the parallel sidewalls of each of the dies being adapted to abut against the corresponding parallel sidewalls of each of the die retaining sockets.

2) The rotary tablet making machine as claimed in claim 1, wherein the endwalls of each of the die retaining sockets and endwalls of each of the dies are curved.
3) A turret of a rotary tablet making machine comprising a lower turret element and an upper turret element and die table sandwiched between the lower turret element and upper turret element, the die table comprising a plurality of die retaining sockets provided at the circumference thereof in radially spaced apart relationship describing a common pitch circle diameter and a plurality of dies each located in each of the die retaining sockets, each of the dies having an open ended tablet forming hole formed therein corresponding to the shape of the tablets to be made in the said machine, the dies being held in the die retaining sockets in position by locking screws tightened against the dies laterally from the outer circumference of the die table, each of the dies being associated with a lower punch up and down movably held in the lower punch element and an upper punch up and down movably held in the upper turret element, each of the lower punch and corresponding upper punch having a plunger head corresponding to the shape of the tablets to be made in the said machine and adapted to enter into and move away from the respective tablet forming hole from the bottom and the top respectively of the tablet forming hole, wherein each of the die retaining sockets and each of the dies comprises a pair of parallel sidewalls, the parallel sidewalls of each of the dies being adapted to abut against the corresponding parallel sidewalls of each of the die retaining sockets.

4) The turret as claimed in claim 2, wherein the endwalls of each of the die retaining sockets and endwalls of each of the dies are curved.