CA1047714A - Pressure-loaded punch and molding machine - Google Patents
Pressure-loaded punch and molding machineInfo
- Publication number
- CA1047714A CA1047714A CA207,023A CA207023A CA1047714A CA 1047714 A CA1047714 A CA 1047714A CA 207023 A CA207023 A CA 207023A CA 1047714 A CA1047714 A CA 1047714A
- Authority
- CA
- Canada
- Prior art keywords
- punch
- cavity
- mold
- molding machine
- pin
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Abstract
PRESSURE-LOADED PUNCH AND MOLDING MACHINE
Abstract of the Disclosure A pressure-loaded punch is described which is particularly adapted for use in rotary molding machines. The punch comprises a body member having a longitudinally extending cavity which contains Belleville washers. A pin extends from the cavity to a region external of one end of the body member so that a force applied to other end of the body member is transmitted through the Belleville washers to the pin.
Abstract of the Disclosure A pressure-loaded punch is described which is particularly adapted for use in rotary molding machines. The punch comprises a body member having a longitudinally extending cavity which contains Belleville washers. A pin extends from the cavity to a region external of one end of the body member so that a force applied to other end of the body member is transmitted through the Belleville washers to the pin.
Description
~047714 23672 PRESSURE-LOADED PUNCH AND MOLDING MACHINE
Various types of rotary molding machines are known which are adapted to compress particulate material into tablets or pellets. These machines are commonly employed in the pharmaceutical industry and in the chemical industry to produce catalyst pellets. m e machines are provided with a plurality of dies which are filled sequentially with the particulate material to be compressed. Punches are inserted into both ends of the dies ~`~ and are moved together to compress the material to form a pellet. One of the punches is then withdrawn, and the second punch is pressed through the die to expel the pellet.
In many applications, it is important that the resulting pellets have uniform density, particularly when the pellets are formed of a catalytic material. It has been found that commercially available machines often produce pellets of nonuniform density due to the fact that slightly different amounts of particulate material may enter the die and the lengths of the punches may not be absolutely uniform. In United States Patent 2,921,339, to Emory W. Pitzer, issued January 19, 1960, there is disclosed a rotary molding machine which includes a gas-actuated cylinder to control the force exerted by a punch in order to provide pellets of more uniform density.
While the use of such a gas-operated cylinder has improved the operation of rotary molding machines, a need exists for a machine which is capable of making even re uniform pellets.
In accordance with this invention, such a machine is provided by the use of pressure-loaded punches. The punches of this invention comprise a hollow body member having a longitudinally extending cavity therein. The interior of the body member is filled with a compression means, such as a stack of Belleville washers. These washers transmit a force exerted to one end of the body member to a pin which protrudes from the second end of the body member. This pin is adapted to enter the cavity of the ld to compress the particulate material.
In the accompanying drawing:
~ .
.. . . ~ .. . . .
~ ' ' : .: :
., ' '' :'' ' 11~)47714 - FIGURE 1 is a schematic view of a section of a rotary lding machine having a punch of this invention incorporated therein.
FIGURE 2 is a view, shown partially in section, of an embodiment of the punch of this invention.
FIGURE 3 is an enlarged view of a portion of the punch of FIGURE 2.
Referring now to the drawing in detail and to FIGURE 1 in particular, there are shown three spaced plates 10, 11 and 12 which are adapted to rotate together about a common axis. These three plates can correspond to respec-tive plates 72, 70 and 74 of the rotary lding machine described in said U.S.
Patent 2,921,339. The illustrated section of plate 10 is provided with an opening through which the lower end of a punch 13 extends. Similarly, plate 12 is provided with an opening through which the upper end of a punch 14 extends.
Plate 11 carries a ld 15 which has a central opening therethrough. In the illustrated position, the ends of punches 13 and 14 extend into mold 15 to compress material therein into a pellet 16. A downward force is exerted on the top of punch 13 by first pressure roll 17, and an upward force is exerted on the bottom of punch 14 by second pressure roll 18. Roll 18 is mounted on a lever 19 which is pivoted about a stationary axis 20. The second end of lever 19 is connected to a rod 21 which is connected to a suitable adjusting - --20 means, not shown.
In the operation of a rotary lding machine of the type illustrated in FIGURE 1 and in U.S. Patent 2,921,339, cam tracks, not shown, are provided to raise and lower the punches as the three plates are rotated together. At -a filling location, punch 13 is lifted out of the mold cavity and particulate material is introduced to fill the cavity. As the machine rotates, punch 13 is moved downwardly by the upper cam track so as to enter the mold cavity and to exert a compression force on the particulate material. Punch 14 can be moved upwardly for the same purpose. The final compression force is exerted by pressure roll 17 and 18 which move the two punches together to the 30 locations illustrated in FIGURE 1. Further rotation of the plates results in
Various types of rotary molding machines are known which are adapted to compress particulate material into tablets or pellets. These machines are commonly employed in the pharmaceutical industry and in the chemical industry to produce catalyst pellets. m e machines are provided with a plurality of dies which are filled sequentially with the particulate material to be compressed. Punches are inserted into both ends of the dies ~`~ and are moved together to compress the material to form a pellet. One of the punches is then withdrawn, and the second punch is pressed through the die to expel the pellet.
In many applications, it is important that the resulting pellets have uniform density, particularly when the pellets are formed of a catalytic material. It has been found that commercially available machines often produce pellets of nonuniform density due to the fact that slightly different amounts of particulate material may enter the die and the lengths of the punches may not be absolutely uniform. In United States Patent 2,921,339, to Emory W. Pitzer, issued January 19, 1960, there is disclosed a rotary molding machine which includes a gas-actuated cylinder to control the force exerted by a punch in order to provide pellets of more uniform density.
While the use of such a gas-operated cylinder has improved the operation of rotary molding machines, a need exists for a machine which is capable of making even re uniform pellets.
In accordance with this invention, such a machine is provided by the use of pressure-loaded punches. The punches of this invention comprise a hollow body member having a longitudinally extending cavity therein. The interior of the body member is filled with a compression means, such as a stack of Belleville washers. These washers transmit a force exerted to one end of the body member to a pin which protrudes from the second end of the body member. This pin is adapted to enter the cavity of the ld to compress the particulate material.
In the accompanying drawing:
~ .
.. . . ~ .. . . .
~ ' ' : .: :
., ' '' :'' ' 11~)47714 - FIGURE 1 is a schematic view of a section of a rotary lding machine having a punch of this invention incorporated therein.
FIGURE 2 is a view, shown partially in section, of an embodiment of the punch of this invention.
FIGURE 3 is an enlarged view of a portion of the punch of FIGURE 2.
Referring now to the drawing in detail and to FIGURE 1 in particular, there are shown three spaced plates 10, 11 and 12 which are adapted to rotate together about a common axis. These three plates can correspond to respec-tive plates 72, 70 and 74 of the rotary lding machine described in said U.S.
Patent 2,921,339. The illustrated section of plate 10 is provided with an opening through which the lower end of a punch 13 extends. Similarly, plate 12 is provided with an opening through which the upper end of a punch 14 extends.
Plate 11 carries a ld 15 which has a central opening therethrough. In the illustrated position, the ends of punches 13 and 14 extend into mold 15 to compress material therein into a pellet 16. A downward force is exerted on the top of punch 13 by first pressure roll 17, and an upward force is exerted on the bottom of punch 14 by second pressure roll 18. Roll 18 is mounted on a lever 19 which is pivoted about a stationary axis 20. The second end of lever 19 is connected to a rod 21 which is connected to a suitable adjusting - --20 means, not shown.
In the operation of a rotary lding machine of the type illustrated in FIGURE 1 and in U.S. Patent 2,921,339, cam tracks, not shown, are provided to raise and lower the punches as the three plates are rotated together. At -a filling location, punch 13 is lifted out of the mold cavity and particulate material is introduced to fill the cavity. As the machine rotates, punch 13 is moved downwardly by the upper cam track so as to enter the mold cavity and to exert a compression force on the particulate material. Punch 14 can be moved upwardly for the same purpose. The final compression force is exerted by pressure roll 17 and 18 which move the two punches together to the 30 locations illustrated in FIGURE 1. Further rotation of the plates results in
-2- -'' ~ , , :. -1()47714 punch 13 fir~t being lifted out of tho cavity and punch 14 then being movod upwardly to expel the comprcssed pellet. A numbor of machine~ are ava~lablo commorcially to carr~ out oporations of this type. One ~uch machino, which i~ doscribed in U. S. Patent 2,921,339, is manufactured by F J. Stoke~
Machino of Philadelphia, Pennsylvania. Another machino i~ the ~odol 216 Rotary Tablet Press manufactured by Chorry-Burrell Corporation Or Cedar Rapids, Iowa.
Punch 13 is illustrated in detail in FIGURES 2 and 3. The punch compri~es a cylindrical body m~ber 25 which is provided with a longitudinally e~tonding cavity 26. A cap 27 is threaded to the upper end of bodr member 25.
Cap 27 is of such a configuration as to ride in the cam track of tho molding machino 80 as to be movod upwar~l~ and downwardly as the machine rotates. A
section of bod~ 25 can bo knurled so as to bo gripped when tho cap is to be throadod onto or removod from the body mombor. The cap can be pro~ided with a hole 28 through which a pin is extended to assemble tho punch. A guido member 29 having an opening therethrough, i9 threaded to the second end of body member 25. A pin 30, which has a shoulder 31 at the upper ond thereof, extends through guide member 29. A spacer 32 rests on the top of shoulder 31.
The intorlor cavlty 26 of body membor 25 contains a compresqion means which extonds between spacer 32 and a disk 33 which is carrled by the top Or a guide rod 34. This comprossion mean~ preferably comprlses a stack Or Bellevillo ~asher~ 36. As illustrated in greator detail in FIGURE 3, tho indivldual washera are positioned 80 that altornate washers are concave upwardly and downwardly. As an alternative, groups Or two, three or more ad~acent washers can be conca~e upwardly, with ad~acent groups concave downwardly. ~his provides a higher strength co~pression means. Guide member 29 can bo an intogral part of member 25 if desired. However, the separate structure permits pin 30 to be replaced without removing the washers.
The stack of Belleville washors results in a substantiall~ constant prossure being applied from roll 17 to pin 30 which extonds into the mold cavltyO The magnitude Or the force thus tran~mitted can be ad~usted by 1~47714 changing tho numbor of wa~her~ within cavity 26 and/or the strongth~ Or the individual wa~hors. It has boon found that the Bellevillo Waaher~ ~er~o to pro~ido a ~ub3tantiallJ constant forco on tho punch pin. Howevor, other comprossion means, such as a coiled spring or a pnoumatic prossure, can al80 bo omployed. It i~ important that the molding maohine bo adJwtod 80 that tho compresslon moans yiolds as tho punches are moved togothor. A yield of ~ome 0.025 to 0.050 inch ba~ been found to bo oatisractor~. If there i~ no yield, the pres~ure applied to the pellot ia not controlled.
; A punch 13 Or the configuration of FICURE 2 W e~aluatod in a co~ercial molding machine as compared with a con~ontion~l solid punch. Tho o~aluation ~as made in con~unction with the manufacturo Or dehydrogenation oatalyst pollets fro~ a fine powder. Pelleta Or three si~ea wero prepared by adJustment Or tho machine. In the control run~, a solid punob was employed in placo o~ punch 13 Or this invention. The operating conditionq were ~ -othorwise the same. The rosults wero as follows:
i Solid Pun¢h SDrin~-loaded Punoh Pellet Length, PoIlet Pellot Crushing Pell~t Pollet Crushing Machino Sotting Length Density Strongth Length ~en~ity Strengtb (inch~ ~ ( ~ cc? ounds) (inch) ( ~cc) (pound~
.120 .12~0 1.~0 1.0 .1193 1.67 3.4 ~ .
.125 .1256 1.67 4.4 .1246 1.66 3.7 .130 .1300 1.94 11.6 .1297 1.68 4.8 It can be aeen that s~all changos in length (.005 inch) resulted in substantial changes in den~ity and crushing strength whon the solid punch wa~ employed. Nuch re uniform pellets were produced with the spring-loaded punch.
While this invention has been described in con~unction with presentl~ preferred embodiments, it ob~iously i~ not li~ited thereto. --' - .
- .:
. ` - .
.
Machino of Philadelphia, Pennsylvania. Another machino i~ the ~odol 216 Rotary Tablet Press manufactured by Chorry-Burrell Corporation Or Cedar Rapids, Iowa.
Punch 13 is illustrated in detail in FIGURES 2 and 3. The punch compri~es a cylindrical body m~ber 25 which is provided with a longitudinally e~tonding cavity 26. A cap 27 is threaded to the upper end of bodr member 25.
Cap 27 is of such a configuration as to ride in the cam track of tho molding machino 80 as to be movod upwar~l~ and downwardly as the machine rotates. A
section of bod~ 25 can bo knurled so as to bo gripped when tho cap is to be throadod onto or removod from the body mombor. The cap can be pro~ided with a hole 28 through which a pin is extended to assemble tho punch. A guido member 29 having an opening therethrough, i9 threaded to the second end of body member 25. A pin 30, which has a shoulder 31 at the upper ond thereof, extends through guide member 29. A spacer 32 rests on the top of shoulder 31.
The intorlor cavlty 26 of body membor 25 contains a compresqion means which extonds between spacer 32 and a disk 33 which is carrled by the top Or a guide rod 34. This comprossion mean~ preferably comprlses a stack Or Bellevillo ~asher~ 36. As illustrated in greator detail in FIGURE 3, tho indivldual washera are positioned 80 that altornate washers are concave upwardly and downwardly. As an alternative, groups Or two, three or more ad~acent washers can be conca~e upwardly, with ad~acent groups concave downwardly. ~his provides a higher strength co~pression means. Guide member 29 can bo an intogral part of member 25 if desired. However, the separate structure permits pin 30 to be replaced without removing the washers.
The stack of Belleville washors results in a substantiall~ constant prossure being applied from roll 17 to pin 30 which extonds into the mold cavltyO The magnitude Or the force thus tran~mitted can be ad~usted by 1~47714 changing tho numbor of wa~her~ within cavity 26 and/or the strongth~ Or the individual wa~hors. It has boon found that the Bellevillo Waaher~ ~er~o to pro~ido a ~ub3tantiallJ constant forco on tho punch pin. Howevor, other comprossion means, such as a coiled spring or a pnoumatic prossure, can al80 bo omployed. It i~ important that the molding maohine bo adJwtod 80 that tho compresslon moans yiolds as tho punches are moved togothor. A yield of ~ome 0.025 to 0.050 inch ba~ been found to bo oatisractor~. If there i~ no yield, the pres~ure applied to the pellot ia not controlled.
; A punch 13 Or the configuration of FICURE 2 W e~aluatod in a co~ercial molding machine as compared with a con~ontion~l solid punch. Tho o~aluation ~as made in con~unction with the manufacturo Or dehydrogenation oatalyst pollets fro~ a fine powder. Pelleta Or three si~ea wero prepared by adJustment Or tho machine. In the control run~, a solid punob was employed in placo o~ punch 13 Or this invention. The operating conditionq were ~ -othorwise the same. The rosults wero as follows:
i Solid Pun¢h SDrin~-loaded Punoh Pellet Length, PoIlet Pellot Crushing Pell~t Pollet Crushing Machino Sotting Length Density Strongth Length ~en~ity Strengtb (inch~ ~ ( ~ cc? ounds) (inch) ( ~cc) (pound~
.120 .12~0 1.~0 1.0 .1193 1.67 3.4 ~ .
.125 .1256 1.67 4.4 .1246 1.66 3.7 .130 .1300 1.94 11.6 .1297 1.68 4.8 It can be aeen that s~all changos in length (.005 inch) resulted in substantial changes in den~ity and crushing strength whon the solid punch wa~ employed. Nuch re uniform pellets were produced with the spring-loaded punch.
While this invention has been described in con~unction with presentl~ preferred embodiments, it ob~iously i~ not li~ited thereto. --' - .
- .:
. ` - .
.
Claims (4)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A pellet molding machine comprising:
a mold having first and second holes at opposite ends thereof, which mold is adapted to receive material to be compressed to form said pellet;
a first punch having a body member having a cavity therein and an opening extending through one end thereof with a pin extending from said cavity through said opening beyond said one end of said cavity so as to be free to enter said first hole of said mold and form a molding surface for one entire end of said mold;
a stack of Belleville washers with adjacent washes in said stack being concave in different directions, extending through said cavity so that a force exerted on the end of said body member opposite said one end is transmitted by said Belleville washers to said pin; and a second punch adapted to enter said second hole of said mold to form a molding surface for the other entire end of said mold.
a mold having first and second holes at opposite ends thereof, which mold is adapted to receive material to be compressed to form said pellet;
a first punch having a body member having a cavity therein and an opening extending through one end thereof with a pin extending from said cavity through said opening beyond said one end of said cavity so as to be free to enter said first hole of said mold and form a molding surface for one entire end of said mold;
a stack of Belleville washers with adjacent washes in said stack being concave in different directions, extending through said cavity so that a force exerted on the end of said body member opposite said one end is transmitted by said Belleville washers to said pin; and a second punch adapted to enter said second hole of said mold to form a molding surface for the other entire end of said mold.
2. The molding machine of claim 1 further comprising a guide rod extending from the end of said cavity opposite said one end through a portion of said stack of Belleville washers.
3. The molding machine of claim 1 wherein said pin is provided with a shoulder at the end thereof adjacent said cavity, said shoulder engaging said body member to restrict movement of said pin in the direction of said one end.
4. The molding machine of claim 1 comprising in addition means to move said second punch forward to expel said thus molded pellet.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US42810273A | 1973-12-26 | 1973-12-26 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1047714A true CA1047714A (en) | 1979-02-06 |
Family
ID=23697565
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA207,023A Expired CA1047714A (en) | 1973-12-26 | 1974-08-14 | Pressure-loaded punch and molding machine |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1047714A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10973759B2 (en) | 2012-11-20 | 2021-04-13 | Intervet Inc. | Manufacturing of semi-plastic pharmaceutical dosage units |
-
1974
- 1974-08-14 CA CA207,023A patent/CA1047714A/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10973759B2 (en) | 2012-11-20 | 2021-04-13 | Intervet Inc. | Manufacturing of semi-plastic pharmaceutical dosage units |
| US11911503B2 (en) | 2012-11-20 | 2024-02-27 | Intervet Inc. | Manufacturing of semi-plastic pharmaceutical dosage units |
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