|Publication number||US2774988 A|
|Publication date||Dec 25, 1956|
|Filing date||Apr 27, 1953|
|Priority date||Mar 23, 1948|
|Publication number||US 2774988 A, US 2774988A, US-A-2774988, US2774988 A, US2774988A|
|Inventors||Frank E Stirn, Arthur S Taylor|
|Original Assignee||American Cyanamid Co|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (5), Referenced by (15), Classifications (8)|
|External Links: USPTO, USPTO Assignment, Espacenet|
Dec. 25, 1956 F. E. STIRN ETAL CAPSULE FORMING GELATIN FILM STRIPPING 6 Sheets-Sheet 1 Original Filed March 23, 1948 ATTORNEY Dec. 25, 1956 F. E. STIRN ETAL 2,774,938
CAPSULE FORMING GELATIN FILM STRIPPING Original Filed March 23, 1948 6 Sheets-Sheet 2 mm W WEI
INVENTOR5 Pfl/VA JT/PNI. VP 6. 7-4/4 05) ATTORNEY INVENTORS Dec. 25, 1956 F. E. STIRN ET AL CAPSULE FORMING GELATIN FILM STRIPPING 6 Sheets-Sheet 3 Original Filed March 23, 1948 BY W W ha f ATTORNEY Dec. 25, 1956 F. E. STIRN ET AL 2,774,988
CAPSULE FORMING GELATIN FILM STRIPPING Original Filed March 25, 1948 6 Sheets-Sheet 4 BY WWW M ATTORN EY 6 Sheets-Sheet 5 F. E. STIRN ETAL CAPSULE FORMING GELATIN FILM STRIPPING Dec. 25, 1956 Original Filed March 23, 1948 'IIIIIIII I n. n 4' .l
INVENTORS FP4/VA 'f. 6771 4/?77/4/4 6. 7-4/1 0 Dec. 25, 1956 F. E. STIRN ET AL 2,774,988
CAPSULE FORMING GELATIN FILM STRIPPING Original Filed March 23, 1948 6 Sheets-Sheet 6 ATTORNEY United States Patent CAPSULE FORlVIlNG GELATIN FILM STRIPPING Frank E. Stim, Pearl River, and Arthur S. Taylor, Spring Valley, N. Y., assignors to American Cyanamid Company, New York, N. Y., a corporation of Maine Original application March 23, 1948, Serial No. 16,554, now Patent No. 2,663,128, dated December 22, 1953. and this application April 27, 1953, Serial No,
2 Claims. (Cl. 18-15) This invention relates to a method and apparatus for stripping soft gelatin strips from a casting surface on which the strips are formed; particularly by repeatedly striking the soft strip gentle blows with a counter-rotating paddle wheel.
This application is a division of our co-pending application Serial Number 16,554, entitled Method and Masoft gelatin strip from a casting surface with a minimum of deformation of the gelatin strip.
It is an additional object of the invention to remove a soft gelatin strip from a casting surface with a minimum of stretch in order that symmetrical soft gelatin capsules may be more easily formed from an essentially unstretched gelatin film.
It is a still further object of the invention to provide a soft gelatin strip at such a rate and with such uniformity of stripping that the so formed gelatin strip is uniformly fed to the capsuling operation and is homogeneous; without any undue local over-stretching which may result from removing the gelatin strip from the casting surface by tension alone.
Further objects, advantages and meritorious features will appear from the following description, appended H certain of the drive mechanisms for the various gears,
cams and rollers.
Figure 3 is a pictorial view showing the paths of the plastic strips as they pass through the machine.
Figure 4 is a top view of the sealing film turn-over mechanism.
Figure 5 is an elevation of a portion of the die roll structure showing temperature control elements and the positioning mechanism of the filling heads.
Figure 6 is a front view of the stator of the cavity die roll, showing the pressure and vacuum chests, heat control, etc.
Figure 6a is a side view of the stator.
Figure 7 is an enlarged view of a single die of the die roll and its cooperating filling head.
Figure 8 is a pictorial view of a filling head.
Figure 9 is a view showing the various coordinated phases of the die wheel operation.
Figure 10 is a fragmentary view onan enlarged scale taken along the line 1010 of Figure 9, showing the ice Figure 11 is a similar view along the line 11-11 of Figure 9showing the die cavity containing the deformed lower film with the filling head in filling position as the powder flows into the cavity.
Figure 12 is a similar view along the line 1212 of Figure 9 showing the filled individual cavity as the upper sealing film is positioned thereover.
Figure 13 is a similar view along the line 1313 of Figure 9 showing the joining and cutting out of portions of the two films to form the individual capsule.
Figure 14, along the line 1414 of Figure 9, shows the air ejector mechanism whereby the capsule is ejected from its mold, showing more particularly how the capsule rounds out as it is ejected, forming with a substantially equatorial joining line.
This improved apparatus is designed to rapidly and efficiently produce capsules of consistent size. In the past it has been common to produce soft gelatin capsules filled with liquid or with pastes. If solids were to be encapsulated, such solids were dispersed in a liquid to form a paste so that the materials could be filled on the then existent machines.
With the development of purer and more potent vitamin products, the use of materials such as fish liver oil has given way to the use of more constituents of vitamin capsules in solid form. Many of the vitamins are now obtainable or maybe converted to a particulate form, and their use in a powdered form possesses certain conveniences and therapeutical advantages, the full commercialization of which has been handicapped by the lack of a suitable encapsulating machine.
The use of powders has long been known in hard gelatin capsules, in which the capsule body is first formed, then filled, and then a cap placed thereupon. The prior art has been uniformly unsuccessful in producing satisfactory, adequate, and cheap machines for the fillingof powders into soft gelatin capsules. Our machine fills the need. It will rapidly, easily and accurately form such powder filled capsules. This machine can be readily and conveniently adapted to fill liquids or pastes or can be used with films of material other than gelatin, if such materials are plastic, are capable of being formed into films, and if such films will unite with each other when passed through sealing rolls.
More. particularly, in our machine, molten gelatin as described-below, is prepared and fed into the hopper 21.
. For temperature control it is desirable that the hopper be equipped with a thermostatically controlled heater element 21h so that the gelatin may be kept at a desired temperature. If the hopper is constructed of brass the heat conductivity of the material will enable the heat to be applied at one location, as shown in Figure 1. If other materials of construction are used, a more uniform distribution of heat over its surface may be desirable. A jacketed hopper may be used with a suitable fluid heat transfer medium. The hopper 21 may be filled by a gelatin supply line 22 connected to a suitable source by which the gelatin in the hopper is maintained at a reason ably uniform level. The gelatin hopper may be equipped with a transparent plastic top or itself be of transparent materials in order that the gelatin level may be observed,
- but yet maintained free from danger of contamination,
' wheel 24, which wheel is formed preferably from a metal lower film in positon over the die cavity.
suchas cast iron 'which should be given a highly polished surface, as for example by chrome plating. .The hopper with the attached doctor blade is preferably adjustably 'locatable by means of links 25 and 26 and adjustable shoes or rollers 21s, riding on the surface of the casting amas roll so that the thickness of the gelatin film may be conveniently regulated. The hopper may be rigid if the doctor blade floats in the desired relationship to the drum surface.
The doctor blade may be divided vertically inthe center and each division made independently adjustable so that two separate thicknesses of film maybe cast at the same time so that the two different films'will each be of independently adjustable thickness. This individual adjustability is of value in adjusting .the position of the equatorial seal and in insuring that the wall thickness of the different portions of the capsule will be'in accordance with the operators desires.
The gelatin film is split into two portions by a splitting roll 27 which is a reasonably sharp rotatable knife, spring loaded by an adjustable spring mechanism 258 so as to separate the cast film into two separate strips. The split.- ting roll may be located adjacent to thege'latin hopper as shown, or may be located further around the casting wheel. It is only necessary that the gelatin film be somewhat solid at the splitting point, so that the gelatin will not how back together after being split.
The entire mechanism is best located in an air ,conditioned room so that both temperature and humidity may be controlled so as to maintain the gelatin 'filminthe desired condition throughout. The casting wheel is covered with a shield v2 9 which is located so that it :is adiacent to but does not interfere with the rotation of the wheel. An exhaust ductis provided through which the air is eX- hausted so that dry conditioned :air from the room is pulled through .the casting wheel shield 29 where itdries and conditions the surface .of the gelatin film, and is exhausted either into the room Oran exhaust duct, depending upon moisture load conditions. The casting Wheel is suitably supported from a main frame 31 and driven in suitably timed relationship with the rest of the mechanism by a mechanical drive means.
The partially dried and conditioned gelatin strip is removed from the casting wheel by a stripper paddle 33. The stripper paddle is driven by a belt or other suitable drive at a faster speed than the peripheral speed oflthe casting wheelzso as to pull off the gelatin film by its action. The repeatedsoft blows ;of the leading edges of this paddle as the paddle is rotated has a tendency to strip the gelatin film without damaging or stretching the film. It is highly advantageous in the production of spherical capsules that the gelatin film be not'stretched.
Undercertain operating conditions as is later described, it is desired to stretch markedly the gelatin film by keeping it-under tension, .andforming the capsule While under tension. Under such conditions, a stripping roll may be substituted for the .paddle. When so formed the gelatin strip material attempts to ,pull back ':to its original shape to relieve the strain' and accordingly, elliptical capsules are produced from round :molds. If elliptical shaped capsules' are desired,they may 'be'produced in round dies by prestretching the film. Under-the normal relationships, whereiit is desired that .a round die cut a roun'dcaps'ule, it is accordingly equally desirable that the gelatin :film be not stretched and remain substantially isotropic, so that the finished capsule willn etain the desired shape.
As shown particularly clearly in Figure 3, the two gelatin stripstake separate paths from the stripper paddle. The sealing film 34 goes :above the die roll and may .be supported over guide rolls 35 and 36.0n which may be placed a carrier belt.:3,7. The carrier'belt and rollers should be of a material which will not stick to-the gelatin. It is possible.andlfrequently convenient to use rolls made from Teflon (Polytetrafluoroethylene,.see :U. S. Patent No. 2,230,654 to Plunkett) ,or from sintered metals which arefed withan oilerto-form oiled surfaces-to whichthe gelatin strip willinot adhere. If several :rollersare used, a carrier belt is not tnecessary.
.Afterpassingtover'these guide membersthe strip itself is fed under and ..over aturnoyer mechanism :38. It has e n found that for the e t s in fi to p nsrl adhere to the lower film it is necessary that the casting wheel side of the gelatin sealing film 34 be placed in juxtaposition with the casting wheel side of the lower strip 44. The outer face of the strip forms a toughened and hardened surface, apparently from the evaporation of the moisture therein, so that it is not nearly as adhesive as the protected side ofthe strip. The outer tough side seals only with difiiculty, and such a seal is more fragile and shows a greater tendency to split.
The turnover mechanism as" illustrated, consists of two suitably .jo'urnaled rollers 39 and 40 on a shaft parallel to the die roll axis and two suitably journaled rollers 41 and 42 on an axis perpendicular to the previously mentioned axis and thereabove, so that a belt 59 traveling over these pulleys in the order 40, 42, 39, 41 and back to 40 will pick up the film as shown in Figure 3, lift the same through to a vertical direction, rotate through 90, reverse the film into another twist of 90 so that the film is fed out of this turnover mechanism .with the casting roll side reversed, and shifted laterally so that this film is now in the same frontal plane as is the lower film. The guide rolls 35 and 36 may be driven by a suitable drive system 43 as is shown more clearly in Figure 2. Some of the rolls may be driven by traveling belts, as for example the carrier belt 37, or the turnover carrier belt 50. Certain of the rollers may indeed be allowed to be idler-s if they are jOlllIlZllfid on comparatively friction free bearings so that the gelatin film itself will cause such guide rolls to rotate.
The lower strip of the gelatin 44 is, after being stripped from the casting wheel by the stripper paddle 33, fed over guide rolls 46 and 47. Guide roll 46 may be oiled by means of a brush 45, rotating in a shallow bath of oil. Alternately this guide roll may be made 'of foraminous material, as for example sintered brass, through which oil is fed from a suitable feed mechanism. it is desirable that'a .thin film of oil be maintained on the surface of this roll so that the outside surface of the gelatin film is oiled so that it will not adhere as readily to later portions of the mechanism. The guide roll 46 is preferably driven by a sprocket drive 48, shown in Figure 2, so that the surface speed of the pulley is substantially the same as the surface speed of the casting drum. The roll 47 is driven from roll 46 by a crossed belt roll drive system '32. The lower strip of gelatin 44, thence passes to the cavity die roll 49.
The cavity die roll is a most important feature of the instant machine. The cavity die roll is designed with a plurality of .cavitiesin its peripheral surface, each cavity forming a single gelatin capsule with each rotation of :thecavity wheeL The individual capsule charge is placed in this cavity and it is important that the machine work done informing the cavitydie wheel be of a high order :so -t-hat-thecavities will be of precisely identical dimensions. The consistency of successive charges and the consistency of .the'size of the filled capsules depends, to a large extent, upon the accuracy of this cavitydie wheel. The exact number of cavities in the face of the die wheel is not of critical importance except to the extent that it determines the number of capsules .filled ineach revolustion. Asshowninthe sketch in Figure '3, there are'three rows of cavitiestin staggered relationshiparound the peiriphery of the Wheel. A single row or any number of rowstmay be .used as desired. There may be any desired number of cavities per row around the circumference of the cavity die roll. Forillustrative purposes there are :48 cavities shown in each row in the accompanyingdraw ings. As shown more clearly in Figure'7, each cavity 51, which serves as .a filling chamber is cylindrical in nature and-hasaraised rim 52. The raised rim preferably has a width of approximately one to two times the thickness of the gelatin strip. For small size capsules a width of '0;03 0 inch has proved satisfactory. The height of this raised rim 52, above the surface of-the cavity roll should be at least twice and preferably about three times the thickness of the individual gelatin film. The cavity' roll surface 53 is in general the surface of a cylinder butits' accuracy is not particularly critical. The surfaces of the raised rim are necessarily very accurate as this raised rim must contact the sealing roll at all portions, during rotation, to give a good cut-out of the capsule.
The cavities may be elliptical, hexagonal, square, or such other shape as may be desired. The cavity may taper towards the bottom, although no particular advantage is found therein. Such modifications are within the scope of the invention, but are not frequently useful, as the complexity of the machining operations involved usually outweighs the advantages.
Each cavity has inserted therein an ejector plug 54. For cylindrical cavities this plug is cylindrical in configuration With a rim 55 thereon. These plugs fit loosely into a plug retainer 56. The plug retainer should fit rather snugly into the cavity so that it will retain its position therein during operations. It may, of course, be held by pins, set screws, or other suitable means if desired, but with good machine shop facilities available it is usually cheaper to merely make this plug a press fit. Either the rim of the plug or the bottom of the cavity should be slightly rough or serrated as shown at 57, so that the plug can not seal tight against the bottom of the cavity. The bottom of the cavity has an air duct 58 leading from its bottom through the cavity die rolls to pressure and suc-. tion chests, as later described. In operation the plug should be of such height that when in its lower position it is substantially even with the upper surface of the plug retainer, so that the filling cavity is a fiat bottomed cylinder. The depth of this cylinder determines the depth of the fill for each individual capsule and should be consistent for all the cavities in the cavity die roll. This is best obtained by using precise machine operations throughout the construction of the cavity, the ejector plug and ejector plug retainer. There must be sufficient clearance around the'edges of the plug so that air from the air duct 58, can raise the ejector plug until its rim contacts the retainer and is thus held in a raised position by air pressure and so that air may be evacuated from the cavity during the evacuation portion of the filling cycle. It is desirable but not necessary that the plug come to approximately the top of the cavity when raised by air pressure as it aids in the ejecting of the capsule. The cavity rim may be built up or the rim and the plug retainer made integral and screwed into the surface of the die roll, or such other construction used as may be more convenient under particular manufacturing conditions, with equipment available.
The individual cavities should be fairly accurately spaced around the periphery of the cavity die roll for convenience, as shown in Figure 3. The cavity rolls should be accurately and firmly journaled, as for example by roller bearings upon a very solid shaft, or the shaft should be solidly journaled upon appropriate bearings, because pressures induced by air pressure and vacuum applied during the filling operations may otherwise cause deflection, undue friction, and chattering of this roll.
By suitable manifolding means, as for example illustrated by Figure 6a, the inside of the cavity die roll 49, has a die roll stator 103 containing a suction chest 59 in contact with the interior surface of the cavity die roll so that air is evacuated through air duct 58, during suitable portions of the filling cycle. Air pressure acts through duct 58 during other portions.
This is most easily arranged by a stator 103 in which is arranged the suction chest 59 which has as an integral part thereof manifolding means such that suction is applied over the desired portion of the filling cycle, i. e. from the point 10-10 to 13-13 as shown in Figure 9. The suction may be applied through a suction connection 104. Air pressure is applied through the air pressure lead 105, which supplies pressure so that the ejector plugs 54 are raised at approximately the point 1414, shown in Figure 9. The use of multiple air blasts, by manifoldingas shown, is particularly effective in clearing the cavities. A spring loaded sealing member 106 may be used to separate the vacuum from the pressure chests, which member may float in the stator so that any wear or unavoidable irregularities in the internal surface on the die roll will be I compensated.
Whereas it is possible to use a stationary shaft upon which the stator is locked, for convenience of drive though the die roll is solidly attached to the axle 75, which is gear driven, and the stator is kept from rotating by a stator positioning'pin 128.
For temperature control of the die roll it is particularly convenient to install heating members in this stator, which may well be of brass. Leads to this heating element are shown diagrammatically at 102. For temperature control it is desirable that the temperature of this stator be controlled, as by a thermostat. Leads to a thermostat are shown at 107. Any suitable type of thermostat may be used, including either one which is integral and individually adjustable or one may be used in which thermocouple leads are taken to an outside control. Many variations of temperature control will be obvious to those skilled in the art, and the exact type of thermal control is not an essential feature of the instant invention.
As shown in Figures 3 and 1, there are positioning pins Won the front surface of the cavity die roll which pins are accurately positioned with respect to the cavities and are used for the positioning of the filling head. In the particular configuration shown there are sixteen pins for forty-eight holes so that three sets of cavities, that is three cavities in each of the three rows, are'filled with each stroke of the filling head. The filling head block 63 is arranged to function in timed relationship with the cavities so that during operation it performs a cyclic shift whereby it is lifted from the surface of the cavity roll,
shifted backwards and allowed to drop to position, being accurately positioned by the pins 60 and remaining in contact with the cavity roll mechanism during a suitable portion of the rotation of the cavity wheel, after which it is raised to repeat the cycle.
The individual filling heads are shown in Figure 7.
Each of them consists of a cylinder 61 in which fits a filler assembly 62. The filler assembly is positionable axially so that its lower edge projects 'below the surface of the filler head block 63 by an adjustable amount, usually equal to from 1 to 2 times the thickness of the film. The filler assembly 62. may be integral or built up and consists of a cylindrical shell through which passes a filler passage 64. This filler passage extends from the supply means, as described later in a hopper through the filler assembly. Around the lower end of the filler assembly is an annular space filled with a foraminous material 65. The foraminous material may consist of felt, sintered glass or sintered metals. For filling routine vitamin products sintered metal is usually particularly convenient because it may be turned to size and even soldered or brazed in location so that the sizing is accurate, and it may be readily sterilized. From the upper surface of this foraminous material there i an exhaust duct 66. The exhaust duct leads into an exhaust annulus 67 cut into the periphery of the filler assembly which is in turn positioned opposite the exhaust manifold 68, which in turn is connected to the exhaust tubing 80.
During the fill operations the filler head block 63 comes down into juxtaposition with the gelatin film'riding on the cavity die roll 49. The exterior diameter of the filler assembly should be such that there is suflicient clearance between it and the cylindrical surface of the cavity for the thickest gelatin film which is to be used with the machine. f
A plurality of these fillerv assemblies are positioned so that the 3 by 3 block of cavities has a filler head in 7 each; The filler heads are mounted in a filler head block 3. 7
As shown diagrammatically in Figure 7, this filler head block maybe equipped with a filler block heater element 108, and a filler block thermostat 1091 As mentioned elsewhere, any of the conventional types of heaters and thermostats may be used. Electrical controlis particularly convenient. Heating of the block is not always necessary but it' is particularly convenient, When the machine is used for hygroscopic powders, as it keeps the block warm' so that moisture will not cause the powder passages or the foraminous material to become clogged.
The filler head block hasmounted thereon a powder hopper 69. The powder hopper is preferably made of transparent material so that its contents may be readily observed. As shown in Figure l, the powder hopper has a stirrer 70 mounted therein which consists of wires mounted on a shaft which is mounted in the top of the powder hopper and is turned by a flexible shaft 71 driven by a suitable source of power. The filler passages extend up to this powder hopper. It is desirable that the stirrer be" rotated" suffi'ciently rapidly to avoid caking or bridging of the powder. If desired the powder hopper may be provided with a feed opening 72 in which. a flexible duct carrying additional powder may be inserted so that the hopper may be filled automatically or manually as may be desired with additional powder during operation of the machine so that the powder hopper is maintained sufiici'ently filled for constant operation without shutdown. For satisfactory results it is necessary that sufficient powder be maintained in the hopper at all times so that no filler passage draws air instead of powder from the hopper.
The filler head block assembly is positioned in relationship to the cavity die roll by means of the eccentric die'roll, clockwise as illustrated, the eccentric 76 contacts the lower end of the lifting arm in approximately the position as shown in Figure 6. At this point the eccentric lifts the arm substantially radially relative to the cavity" die block until the positioning. block 79 clears the positioning pin 69. As soon as this pin is cleared the friction and direction of motion of the eccentric pu-lls the-arm and the accompanying filler head block assembly in" a counterclockwise direction in an elevated position to;approxim'ately the position shown at the dotted line inFigure 5. Atthis point the eccentric pin having passed its top center and having started downward, lowers the arm and the filler head block assembly until the pins '61? pick up the positioning block 79' and cause the entire assembly to rotate clockwise again. As the block is rotated clockwise the eccentric continues to drop until the entire weight of the filler head block restsupon the positioningpins and/or the gelatin film and cavity die roll, at which point the eccentric turns free in the eccentric guide.- opening: until time for the cycle to begin again.
- Anidentical mechanism is present on the back side of the cavity dieroll so that the powder hopper is supported both in front and in back by an-iden-tical symmetrical mechanism. It is usually most convenient that this mechanism be behind the drive for the cavity die roll, For normal operations it-is desirable that the weight of the cavity block rest on the gelatin film rather than on the positioning, pins, so that the gelatin film acts as a seal and prevents the leakage of air around the periphery of the tiller; It is desirable but not necessary that the positioning pins and positioning black bear a relationship such that if the gelatin film is removed by inadvertence; or at the beginning or end of'operation, the weight of the filler block is taken by the pins rather than by the" raised rims of the cavities. If the block' is allowed to pound on the cavities with no, gelatin in between, the rims may becomebatte'red.
By this mechanism and method the filler head block assembly is raised during the non-filling portion of the cycle and positioned again over a new set of cavities. Of course, the filler head block may have more or less filler heads to fil-l more or less cavities than shown per operation provided that the pins are positioned for each group of cavities as desired. Usually for the size capsules which are desired it is more convenient if more than one capsule be filled per row per cycle. As illustrated, three are filled. g
The gelatin strip is fed under the guide roll 47 and into contact with the cavity die roll 49; As shown by the schematic Figure 9, this gelatin strip is positioned on the die roll resting on top of the raised rims 52. At the point shown by the line 10-10, Figure 9, the suction manifoldadmits suction to each cavity through the air ducts 5 8 which causes the gelatin film .to be pulled tight against the raised rim 52 and drawn down therein to form a cup shaped lining in the filling chamber 51. Figure 10* shows the lower film positioned on the raised rim and Figure 11 shows the film having been pulled down into contact with the ejector plug and plug retainer. The suction is maintained on the chamber until after the capsule is sealed and cut-out. Usually a higher degree of vacuum is maintained under the gelatin film than is used above it in the filling operations.
As" the gelatin lined chamber advances the filler head block is lowered into contact therewith, as described above, and shown schematically in Figure 11, taken on line 1111-'. The filler assembly may enter partially into the gelatin lined container. The filling. head itself preferably rests on the gelatin film.
At this portion of the cycle, at about the point 1111 of Figure 9, the filling occurs. The filled powder should be of such consistency in relation to the size of openings that it will not flow through the filler passage 64 under the influence of gravity and such vibrations as occur, but instead, after the machine is in operation, blocks or bridges across the passage.
When the filler assembly is in position, vacuum is applied through the exhaust manifold 68; To insure adequate and proper filling, it is desirable that the air be evacuated through the passage 63 in slugs. This is accomplished by connecting the exhaust tubing 80 to a solenoid operated valve which is connected to a vacuum pump (not shown). The solenoid valve may be actuated by a microswitch 81, which has a contact member I 82, riding upon actuating pins 83, on a cam plate 84.
These contacting pins are so arranged that the solenoid releases the air through the exhaust duct 68 into the vacuum pump in bursts which gives a pulsating flow to the powder and causes it to compact to a uniform density in the filling chamber. The foraminous material 65 prevents the powder from flowing through the exhaust ducts and-insures a comparatively uniform and consistent density of the powder. Under normal operating conditions, if subjected to a series of bursts of vacuum, five being a suitable number although from a single burst to as many as a dozen (for different powders) may be used if desired, a-powder may be compacted to a remarkably uniform density. It has been found that homogeneous powders will be normally compacted by such an. arrangement so that the density of a charge will not ordinarily vary more than a fraction of one percent. If the charge chambers are of consistent size and the gelatin film is cast to a consistent thickness, this will mean that the individual chambers will be filled uniformly so that the final capsules containequal dosages.
I The size of these charges may be adjusted by varying the amount which the filler assembly 62 projects into the charge chamber, or by varying the depth of the 'charge chamber. Some variation may be introduced by varying the pressures and vacuums used.
After the filling operation is completed, and the vac- .uum is released, the filling head block assembly is lifted by means of the cam and lifting arm, as explained above, the filled chamber rotates past the point shown by 1212 as shown by the sketch in Figure 12, at which point the sealing film 34 is brought into juxtaposition with the filled charge chamber by the sealing roller 85. The sealing roller 85 is spring mounted by a sealing roll spring assembly 89 so that the pressure between it and the cavity die roll may be readily varied and so that any irregularities may be compensated by spring action.
As shown in Figures 3 and 5, this sealing roll may have small apertures therein, conveniently though not necessarily mated to match with the cavities in the die roll, through which vacuum is applied as by the manifold 111 and the vacuum connection 110. The suction through these orifices assists in positioning the sealing film so that it will not slide unduly on the surface of the sealing roll. If the particular gelatin compound used appears to stick to the sealing roll, an air pressure assembly, such as is used in the cavity die roll, may be embodied in the sealing roll to assist in releasing the gelatin film and capsules from the sealing roll. As shown at 112, an oil fed wick may rest upon the surface of the sealing roll, being in turn supplied by a suitable oil supply so that a thin film of oil is maintained on the surface of the sealing roll at all times to prevent adherence of the gelatin to this roll. It will be found that if the roll is over-heated the gelatin is particularly apt to stick, and that if a gelatin mix requires a higher temperature, particular care is necessary to insure that this roll have a high gloss and be adequately oiled to prevent sticking or building up of gelatin on the surface.
As more particularly shown in Figure 5, a heater member 86 is in contact with the side of this sealing roll stator 113, and is thermostatically controlled by means of a thermostat 87 so that the temperature of this roll may be maintained as desired. Whereas the thermostat and the heater are shown in a stator, they may be built as sliding upon the side surface of this sealing roll or the heater and the thermostat may be built integral with this sealing roll and connections may be by sliding contacts brought out through the axle if desired.
The stator is retained in position by the sealing roll stator positioning pin 129 and its associated bracket 130. The temperature adjustment of this roll may be critical as will be later described.
As the cavity die roll and the sealing roll rotate together, the spring action above described, first causes the sealing film 34 to contact the lower strip 44 and then to press upon this lower strip which in turn is supported by the raised rim 52, until the raised rim cuts into the combined gelatin films, as shown at Figure 13. The compression action caused by this pressure causes the gelatin caught between the raised rim and sealing roll to be extruded and as it is pressed between these members it unites with itself so that a sealed joint is formed. The two gelatin fihns under proper operating conditions are so uniformly united that it requires inspection to locate the seal and the seal is nearly as strong as the wall of the capsule. The residual web 88, is forced down on the outside of the raised rims 52 and into the space provided therein. As the two rolls separate as they turn, air pressure may be applied by means of a manifold under the cavity die so as to raise the ejector plug 54 as shown in Figure 14, taken along the line 1414. This action of raising the ejector plug causes the filled capsule to be pressed out of the chamber and allows it to spring to its natural shape.
To give a good clean seal and to cut the gelatin completely out of the web it is desirable that the sealing roll spring assembly 89, press comparatively firmly upon the surface of the sealing roll. If there are any irregularities in the rim, a small flash may remain which may cause the capsule to stick in the web, but under normal operating conditions, if the rolls are accurately made, the capsules will be completely detached. As shown in Figure 1 and in Figure 9, the capsules after passing the line 14-14 have a tendency to be ejected by the plug and air pressure. This is followed by the action of two revolving brushes 90, which rotate in a counterclockwise direction at a comparatively high rate of speed, their peripheral speed being several times the surface speed of the cavity die roll. These brushes have an additional tendency to throw the capsules upon a conveyor belt 91 which removes the capsules to a discharge point. The web with the capsules cut on thereof is pulled around the web roller 92 and through the web removal rollers 93, which rollers are rotated at a slightly higher surface speed so as to pull the web and stretch it so that it is easily removed. The web from this point is fed to a waste container or otherwise disposed of. Other means may be used to remove the residual web, as frequently just gravity is adequate. Individual suction cups, brushes, and other methods shown in the prior art may be used.
The sealing roll spring assembly 89 may be any conventional universal assembly whereby the spring loaded sealing roller is permitted to run in contact with the gelatin contacting the cavity die roll. As shown, the axles of these two rollers are maintained essentially parallel by the slots in the retaining frame 94. However, in and out motion in the direction of the line of centers is permitted and occurs against the spring, compression of which is adjustable by means of the tightening handle 95.
Figure 2 shows in diagrammatic form the driving belt system for the machine. For normal operation, as herein described, it is desirable that the gelatin strip remain slack but not loose at all points. Tension should be avoided in the gelatin strip. This is most easily accomplished by insuring that the surface speed of each of the gelatin contacting rollers is the same as the surface speed of the casting wheel. Normally the gelatin film will have a tendency to shrink from drying after it is removed from the casting wheel, but at' the same time will have a tendency to stretch because of the warming of the gelatin and because of the natural weight of the gelatin tending to stretch it as it passes over the rollers. In general, it will be found preferable to drive the rollers by positive means by either sprockets and chains or by direct gearing. This automatically tends to stabilize the length of the cast film. The number of teeth in each of the gears is not critical nor is the size of the rollers, but they should be so related that the surface speed of all rollers be substantially uniform throughout; with the exception of rollers 93, the web removing rollers, which may be driven at a higher speed to remove the film.
Because of the peculiar properties of gelatin, it has a tendency to be slowly elastic. If stretched, a film of gelatin has a tendency to recover its original shape slowly. Accordingly, if the gelatin strip is stretched at any point during its passage through the machine it will tend to recover to its original dimensions, though slowly. If desired, advantage may be taken of this characteristic by stretching the film by driving the casting roller slower than the other rollers in the machine. If this is done, after the capsules have been cut and emerged from the die roll as essentially spherical, the gelatin films forming the capsule will shrink in the direction in which they were originally stretched in such a fashion as to give a football shaped capsule. This casting of elliptical capsules from round cavities is an important feature of this invention, but is not necessarily an essential feature; as if it be desired to cast spherical capsules, by the same token, this same stretch must be avoided.
As shown in Figures 1 and 2, a drive motor 96, through a worm gear system 97 drives the main shaft 98 which in turn drives the casting wheel by means of the casting wheel gear system 99. In the particular modification shown, beveled gears 100 drive a jackshaft 101 on which are mounted sprockets for driving various parts of the machine. Each of the rotating drive wheels is preferably driven in some fashion from a powered shaft with the exception of spring loaded roll 85, which maybe driven merely by contact because of the high pressure between it and the cavity die roll.
If mated vacuum openings 114 are used, the roll 85 should be geared or otherwise positively driven in timed relationship with the cavity die roll as shown.
Only one drive pulley is necessary for each of the belted roller systems.
Figure 2 shows diagrammatically certain aspects of a particular system or roller drives which has proved satisfactory. It is readily Within the range of anyone skilled in the art to work out other methods of drives which are satisfactory for driving the various members at the speeds shown to be desirable elsewhere in this specification. As shown in Figure 2 from the jack-shaft 101 there is a main chain roller drive 115 which drives the cluster shaft 116. From this cluster shaft by means of a paddle drive belt 117 the paddle 33 is driven. By means of the sprocket drive 48 and an associated belt drive the guide rollers 46 and 47 are driven from the same shaft. The turn-over mechanism is driven by means of a turn-over mechanism chain drive 118. The carrier belt 37 is driven by an appropriate carrier belt drive 119. From the cluster shaft 116 by means of a suitable idler gear 120 is driven the eccentric shaft 77 and related mechanism, by an ecentric shaft gear 121. In turn therefrom, through idler gear 122 is driven the cavity die roll"'gear 123 and in turn therefrom the sealing roll gear 124.
From the jack-shaft 101 by means of the web removal roller sprocket drive 125 there is driven the web removal rollers and by an associated belt and pulley system functioning as a discharge conveyor belt drive 126, the K discharge belt and associated mechanism is driven. From this in turn is driven the revolving brush drive system 127.
The entire drive system is within the skill of the art and may be readily modified in any number of various ways without departing from the scope of the invention. It is to be noted that, in the system as shown, by changing one sprocket in the main chain roller drive 115 and coordinating the sprocket drive chain length therewith, it is possible to change the speed relationship between the cavity die roll and all gelatin strip contacting members affiliated. therewith and the casting wheel itself, so that it is possible to readily arrange various degrees of stretch in the gelatin film when and if desired. If greater flexibility is desired a variable speed drive system may be installed at this point so that variations in the degree of stretch may be accomplished while the machine is in actual operation.
Certain examples of the use of the machine are described in our above mentioned Patent 2,663,128.
As our invention, an improvement to the art of making capsules, we claim:
1. An apparatus for the production of soft gelatin strip for capsule manufacture, comprising a continuously moving casting surface, means for casting a continuous gelatin strip thereon, a multibladed counter-rotating paddle wheel adjacent said casting surface at the gelatin strip take-off point and contacting the gelatin strip, means for rotating said paddle wheel at higher peripheral speed than the speed of the casting surface, and strip conveying means drawing the strip away from the paddle wheel, whereby the gelatin strip is repeatedly contacted by the leading edges of the paddles, and thereby pulled free from the casting surface with a minimum of stretching.
2. In an apparatus for the manufacture of soft gelatin capsules, a continuously moving casting surface, means for casting a continuous gelatin strip thereon, including a gelatin hopper, and support means resting on said casting surface for said hopper, means for cooling and partially drying the gelatin strip, a multibladed counterrotating paddle-Wheel adjacent said casting surface at the gelatin strip take-off point and contacting the gelatin strip, means for rotating said paddle-Wheel at a higher peripheral speed than the speed of the casting surface, and strip conveying means drawing the strip away from the paddle wheel, whereby the gelatin strip is repeatedly contacted by the leading edges of the paddles, and thereby pulled free from the casting surface with a minimum of stretching.
References Cited in the file of this patent UNITED STATES PATENTS 590,017 Evans Sept. 14, 1897 1,235,716 Mooney Aug. 7, 1917 2,116,916 Van Hyning May 10, 1938 2,556,247 Zeigler et al June 12, 1951 2,654,123 Hall Oct. 6, 1953
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|U.S. Classification||425/223, 264/DIG.370, 425/447, 425/310|
|Cooperative Classification||Y10S264/37, A61J3/07|