Patent Publication Number: US-6209296-B1

Title: Machine for enrobing tablets with gelatin and die blocks for use therein

Description:
This application is a continuation-in-part of U.S. patent application Ser. No. 09/059,144 filed Apr. 13, 1998, now U.S. Pat. No. 6,018,935. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates to an apparatus for enrobing medicine and other ingestible tablets in a digestible film. 
     The pharmaceutical industry commonly provides drugs in the form of a capsule or tablet that can be readily swallowed by a person. The dosage form known as a tablet is solid and hard with a predetermined shape. Its active ingredients are held together with a suitable binder. 
     Recent U.S. Pat. No. 5,146,730 issued Sep. 15, 1992 to Banner Gelatin Products Corp. teaches a method and apparatus for producing medicine tablets that are enrobed in a gelatin coating formed by applying two layers of film to opposite sides of the tablet. Hard cores or preforms are dispensed on a self-timed basis into simultaneous contact with the two films which are supported on coacting rotary dies that come together to form a nip. The hard cores contact the films adjacent this nip at places which overlay recesses formed in the dies. The elastic films deform around each core and are sealed by the dies to each other. The dies then cut the covered cores from the films. 
     One of the difficulties of this known apparatus is that the rotary die members which are believed to be made of metal are quite expensive to manufacture. If one or both of the rotary dies should be damaged for any reason, it may be necessary to completely replace one or both of the rotary die members at a substantial cost. Furthermore, if this should occur and it becomes necessary to shut down a manufacturing operation until the one or more rotary dies are replaced, there is likely to be substantial additional expense and loss as a result of the shutdown in operations. 
     Recent U.S. Pat. No. 5,682,733 issued Nov. 4, 1997 to the present applicant describes another apparatus for enrobing tablets, which apparatus employs a main linked track of die blocks with each block having a number of recesses formed in its top surface. There is also a revolving cooperating die device which can be either another linked track or a cylindrical rotary die and this device also has a plurality of recesses, each of which is cooperable with a recess of similar size in the main linked track to provide an enclosed cavity capable of holding one of the tablets. A gelatin strip is delivered to the main linked track and moves along its upper path. A tablet dispenser drops tablets into depressions formed in this gelatin strip. A second gelatin strip is delivered to the apparatus and is laid over the first strip when the two strips reach a region of contact. 
     It is an object of the present invention to provide an apparatus for enrobing tablets in a layer of gelatin, which apparatus employs rotary die assemblies each with a series of die blocks and which apparatus can be repaired should it become damaged with reasonable speed and at less expense than the prior art rotary die members. 
     It is another object of the present invention to provide relatively inexpensive die blocks for use in an apparatus for enrobing ingestible tablets, these blocks being made of a hard plastics material and each having a number of similar recesses formed in the top. 
     It is a further object of the present invention to provide the aforementioned inexpensive die blocks for enrobing tablets, these blocks having one or more passageways for applying vacuum to the or each recess formed in the block. With these blocks vacuum can be used to pull the adjacent gelatin web into the recess, thereby forming a cup to receive the tablet. 
     SUMMARY OF THE INVENTION 
     According to one aspect of the invention, an apparatus for enrobing tablets in a gelatin layer includes a pair of cylindrical rotary die assemblies, each die assembly including a substantially cylindrical, rotatable die support and a series of die blocks mounted on the die support for rotation about a central axis of the die support. Each block has at least one recess formed in a top surface thereof and each recess of each die assembly is cooperable with a similar recess in the other die assembly to form a cavity at a nip formed by the die assemblies. Each cavity is dimensioned to receive therein one of the tablets. The blocks of at least one of the rotary die assemblies each have one or more vacuum applying passageways that open into the at least one recess. The apparatus also includes a drive system for rotating both die assemblies around their respective central axes so that the two series move in synchronism with each other. Feed apparatus delivers a gelatin strip of selected thickness and composition to each of the die assemblies. During use of the apparatus, each gelatin strip is pulled by a respective one of the die assemblies into the nip and is laid on a section of the series of die blocks of the respective die assembly. A tablet dispensing mechanism dispenses individual whole tablets onto one of the gelatin strips at a feeding location that is upstream of the nip. A vacuum applying device is mounted adjacent at least one of the rotary die assemblies and connectible to a vacuum source. The vacuum applying device extends from a first location adjacent the nip to a second location near the tablet dispenser and has a primary vacuum applying passageway extending therealong. A portion or portions of at least one of the gelatin strips is stretched in the recess by vacuum applied to the recess by the vacuum applying device and the one or more vacuum passageways in the respective block. Each dispensing tablet is held in a stretched portion of the gelatin strip as the tablet moves into the nip. 
     In a preferred embodiment, each die block of each series has a number of recesses arranged in one or more rows extending transversely of its respective die assembly and is made of a hard, plastics material. 
     According to another aspect of the invention, a die block for use in an apparatus for enrobing ingestible tablets of selected size and shape with a gelatin film has a top, a bottom and sides extending between the top and the bottom. There are a number of similar recesses formed in the top with each recess being dimensioned to receive loosely therein at least one half of one of the tablets. A raised rim extends about a perimeter of each recess for cutting a gelatin film laid over the top of the block during use of the block, which is made of hard, plastics material. 
     In a particularly preferred embodiment, the block is made of carbon fibre reinforced plastics material. 
     According to a further aspect of the invention, there is provided a die block for use in an apparatus for enrobing tablets of selected size and shape with an ingestible film, the block having a top, a bottom and sides extending between the top and the bottom. A number of similar recesses are formed in the top with each recess being dimensioned to receive therein at least one half of one of the tablets. A raised rim extends around a perimeter of each recess for cutting a gelatin film laid over the top of said block during use thereof. Each recess has a bottom and at least one sidewall forming a substantially enclosed recess with an open top. The block has two opposite ends and one or more vacuum applying passageways opening into the recesses, including an initial passageway having an open end at one end of the die block. 
     The tablet dispensing mechanism can comprise a number of vacuum applying members arranged in a row extending transversely of the one die assembly and the transfer mechanism includes a slidable frame member on which the vacuum applying members are mounted. 
    
    
     Further features and advantages will become apparent from the following detailed description taken in conjunction with the accompanying drawings. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front elevation of an apparatus for enrobing tablets, a front cover plate being shown in dot-dashed lines and the tablet feeding mechanism being omitted for sake of illustration; 
     FIG. 2 a  is a top view, partly in cross-section showing front and rear support plates for the apparatus of FIG. 1, a bowl feeder, and chutes that feed tablets to the die assemblies; 
     FIG. 2 b  is a detail view illustrating the engagement between each die block and its cylindrical support; 
     FIG. 3 is an elevational view in vertical cross-section showing the two die assemblies of the apparatus and the nip formed thereby; 
     FIG. 4 is an elevational view, partly in cross-section, showing a drive motor and drive shaft for the apparatus; 
     FIG. 5 is a cross-section taken along the line  5 — 5  of FIG. 1 showing details of the die assemblies; 
     FIG. 6 a  is a cross-sectional elevation taken along the line  6   a — 6   a  of FIG. 6 b  showing a scrap ribbon roller and cooperating spring loaded roller mounted downstream of the rotary die assemblies; 
     FIG. 6 b  is a left end view of the rollers of FIG. 6 a  and the mounting therefor; 
     FIG. 7 is a top view of one form of die block usable on the two die assemblies shown in FIG. 3; 
     FIG. 8 is an end view of the die block of FIG. 7; 
     FIG. 9 is a cross-sectional view of the die block taken along the line IX—IX of FIG. 7; 
     FIG. 10 is a side view of a metal bearing ring used to space the die blocks in the assembly, the ring being shown on the side facing the die blocks; 
     FIG. 11 is a front elevation illustrating the front bracket plate that covers the front of the rotary die assemblies; 
     FIG. 12 is a side elevation showing one form of timed tablet dispensing mechanism that can be used in the apparatus of FIG. 1; 
     FIG. 13 is a front view of the tablet dispensing mechanism of FIG. 12; 
     FIG. 14 is a side elevation showing the nip region of a second embodiment of the apparatus for enrobing tablets, this apparatus employing vacuum applying devices; 
     FIG. 15 is a cross-sectional view similar to FIG. 5 but illustrating the second embodiment of the invention and its vacuum applying devices; and 
     FIG. 16 is a cross-sectional detail view showing the construction of the die blocks in the second embodiment. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENT 
     FIG. 1 to  3  illustrate an apparatus  10  for completely enrobing medicine or similar ingestible tablets in a layer of gelatin, one of these finished tablets being shown at  12  in FIGS. 12 and 13. Not shown in FIG. 1 but shown in FIG. 2 is a bowl feeder  14  which per se is of known construction. Also, not shown in FIGS. 1 to  3  is a timed tablet dispensing mechanism, one form of which is shown in FIGS. 12 and 13. This timed tablet dispensing mechanism can be mounted rigidly on a front support plate  18  which extends vertically and which is rigidly attached to a rigid base structure  20  of suitable construction. The structure  20  supports the apparatus  10  on a floor or other suitable horizontal surface and only part of the structure is illustrated. Extending parallel to the plate  18  is a rear support plate  22 . These plates  18 ,  22  as well as other metal components and parts of the apparatus are generally made from aluminium or stainless steel due to health and cleanliness requirements for a machine of this type. 
     Tablets made with the apparatus  10  are completely enclosed and sealed and comprise preforms supplied from the bowl feeder  14  and a gelatin coating made from two webs or films of gelatin indicated at  24  and  28 . Individual preforms are dispensed onto the gelatin strip  24  at a feeding location indicated at  30  which, in a particularly preferred embodiment, is about 6 inches from a nip  32  formed by two cylindrical, rotary die assemblies indicated generally at  34  and  36 . The two gelatin strips  24 ,  28  are brought together at the nip  32 . The die assemblies each include a substantially cylindrical, rotatable die support  38  and a series of die blocks  40  mounted on the die support for rotation about a central axis of the die support  38 . One of these die blocks  40  is illustrated in FIGS. 7 to  9  and it will be understood that all of the die blocks  40  on the two die assemblies can be of identical construction. For ease of manufacture and reduced costs, the die blocks  40  are preferably made of a durable, tough, hard plastics material and can be made by an injection molding process. A preferred form of plastics material is a carbon fiber reinforced plastics material. In one preferred embodiment of the apparatus  10 , the blocks are made of carbon fibre reinforced, heat stabilized polyphthalamide (PPA). This preferred plastics material has a tensile strength of 46,500 psi (ASTM method D638) and a flexural strength of 64,500 psi (ASTM method D790). 
     Each die block  40  has at least one recess  42  formed in a top surface  44  thereof. It will be understood that each recess of each rotating assembly  34 ,  36  is cooperable with a similar recess  42  in the other rotating assembly to form a substantially enclosed cavity at the nip  32  formed by the rotating assemblies. This cavity is dimensioned to receive loosely therein one of the tablets  12 . The illustrated die block  40  has a number of recesses  42  arranged in a single row that extends longitudinally of the die block and transversely of the block&#39;s respective die track  38 . Although the illustrated die block is shown with only one row of recesses, it is of course possible to construct a die block with two or more rows of recesses, if desired. The illustrated recesses are substantially oval in shape in order to accommodate tablets of this general shape, but it will be understood that other shapes, for example, round, are also possible depending upon the shape of the tablets for which the apparatus is designed. In the first embodiment illustrated in FIGS. 7 to  9 , slots or holes  46  can be provided in the bottom of the recesses in order to permit the escape of air from the recesses during the tablet encapsulating process. Each die block  40  is formed with two or more rows of teeth  48  on a bottom  50  thereof. In one embodiment of the block having eight recesses on top, there are nine rows of three teeth per row, each extending transversely of the elongate block. By employing this number of rows of teeth, one ensures that no undue load or stress will be placed on individual teeth as the blocks rotate with the die support. 
     The die blocks  40  are formed with bottom cavities  52 , the number and shape of which can correspond to the number and shape of the recesses  42 . Two rows of the teeth  48  are located on each side of each cavity  52 . Each die block is molded with laterally projecting connecting members  54 ,  56 . In the illustrated embodiment, each of these connecting members comprises three, generally cylindrical protuberances  57 ,  58  and  59  and these are connected by integral webs  60 . These connecting members  54 ,  56  extend respectively into a hole or holes  62  having a similar cross-sectional shape in a metal bearing ring  64 , one of which is shown in FIG.  10 . There are two of these rings  64  mounted in each die rotating assembly, one on each side of the series of die blocks. These rings, which can be made of bronze, act to connect together each series of die blocks so that they are uniformly spaced relative to one another about their respective die support. The rings are detachably connected to the die blocks as the connecting members  54 ,  56  are simply slid into their holes  62 . 
     The preferred die block  40  also includes die locating members  66  that project upwardly from opposite ends of the top of the die block and help to align the die block with another cooperating die block of the apparatus during use thereof. In the block  40  as illustrated in FIG. 7, there is one central die locating member  66  at the left end and two members  66  at the right end. There are also die locating recesses  68  formed at opposite ends of the top of the die block  40 . It is the combination of the members  66  and the recesses  68  which help to align the die block  40  with another cooperating die block. It will be understood that the recesses  68  are sized to receive the members  66  of the cooperating die block which will be arranged so that its end sections are the reverse of the end sections of the first die block. 
     A raised rim  70  extends about the perimeter of each recess  42  for cutting the gelatin web or strip  24 ,  28  after it is laid over the top of the block and is pulled into the nip  32 . The top edge  72  of the rim should be slightly curved from one end of the recess to the opposite end to match the curvature of the circumference of the die support. In this way, opposing rims on opposing die blocks as they pass through the nip  32  will evenly and fully cut through the gelatin webs in order to encapsulate the tablet. Preferably, the rims  70  formed on the top of the die blocks  40  have a width from one to two times the thickness of the gelatin web which is laid over the recess. For example, for a small sized tablet or capsule, the width of the rim can be approximately 0.04 inch. The height of the rim  70  should be more than the thickness of the gelatin web. 
     Returning to FIG. 1, there is shown therein feed means for delivering a gelatin strip  24 ,  28  of selected thickness and composition to each of the die rotating assemblies  34 ,  36 . The films or webs  24 ,  28  are cast on separate, rotating casting drums which per se are of known construction. These drums  74 , 76  can be made of stainless steel. It will be understood that the gelatin in a liquid state is delivered to each drum through a heated hose (not shown). Before use, the gel is stored in a jacketed tank that maintains the liquid gel at a temperature of at least 140 degrees F. By force of gravity, the liquid gel passes through the hoses to a spreader box  75  located at the top of each casting drum. The spreader box itself can be heated with two heating cartridges to maintain the liquid gelatin at a temperature of about 140 degrees F. The liquid gel is spread onto the casting drum which rotates and forms the gel into a ribbon or strip. A fan blower  78  is provided on each casting drum and acts to cool the gelatin so that it is changed into a solid strip that can be peeled from the casting drum at a small, adjustable roller  80 . Preferably a metal cover  79  extends over the strip formed on the drum. The thickness of the gel strip can range from ten to thirty thousands of an inch. Each gel strip passes over a rotating oil roller  82  which applies a thin layer of oil on the outside surface of the strip. The oil helps to ensure the release of the gelatin strip from its respective die rotating assembly after the strip passes through the nip  32 . The gelatin web  24  then extends to the lower die assembly  36  where it is laid on the die blocks  40  located at the top of the assembly. The gelatin web  28  extends to the upper die assembly  34  where it is placed over rotating die blocks extending across the top of the die assembly  34  and down one side thereof to the nip  32 . After the two webs  24 ,  28  pass through the nip  32 , they are adhered to each other and, in this state, they are pulled down through a scrap ribbon puller  84  which is shown in detail in FIGS. 6 a  and  6   b . The used gelatin web can then be deposited in a suitable container (not shown) for subsequent disposal. 
     A drive system is provided for rotating both die assemblies  34 ,  36  about their respective central axes so that the two series of blocks move in synchronism with each other. The start of the preferred drive system is shown in FIG.  4  and it begins with an electric motor  86 . The illustrated motor is mounted on a horizontal support plate  88  but it is also possible to mount the drive motor on the floor. A vertically extending bracket  90  is used to secure the plate  88  to the main rear plate  22  which can be one inch aluminum or stainless steel plate. Four connecting bolts  92  extend between the bracket  90  and the rear plate  22 . An output shaft  94  of the motor is connected to a main drive shaft  96  which is rotatably mounted in the rear plate  22  by means of ball bearings  98 . These bearings are held in place by a bearing cover plate  100  and bolts  102 . A standard shaft coupling  104  secures the motor shaft  94  to the shaft  96 . It will be understood that if the motor  86  is mounted on the floor, suitable pulleys and a drive belt  97  can connect the motor output shaft  94  to the shaft  96 . A drive of this type is shown in part in FIG.  5 . 
     With reference now to FIG. 5, the forward section of the main drive shaft  96  is shown extending through main drive gear  108 . The forward section of the shaft is rotatably mounted in the front plate  18  which can also be one inch plate and in front bracket plate  160 . Ball bearings  110 ,  112  rotatably support the shaft. The drive gear  108  rotates a smaller drive pinion or gear  114  mounted on horizontal shaft  116 . The shaft  116  is supported in ball bearings at  118  and  120 . The bearings  118  are secured in the front plate  18  by means of bearing cover plate  122  and connecting bolts  124 . The shaft  116  which is made of stainless steel supports a drive gear  126  mounted to the rear of rear plate  22 . Gear  126  engages a similar gear  127  mounted on rotatable shaft  131 . The gear  127  operatively engages another similar gear  132  of equal size mounted on stainless steel drive shaft  134 . The shaft  134  extends through the front and rear plates and a passageway formed along the central axis of the upper die assembly  34 . The shaft  134  is rotatably supported by three ball bearings at  136 ,  137 ,  138 . The two series of die blocks  40  and their cylindrical supports are rotated at the same speed. The central shaft  134  is used to properly position the die assembly  34  relative to the lower assembly  36 . 
     A preferred construction of each die rotating assembly  34 ,  36 , will now be explained with reference to FIGS.  3  and particularly FIG.  5 . Reference will be made to die rotating assembly  36  shown in detail in FIG.  5  and it will understood that the assembly  34  is constructed in a similar manner. The main component of the die track is a solid, cylindrical aluminum block  146  through the center of which is a passageway  148  which accommodates the forward end section of the main drive shaft. A series of small, transversely extending teeth  150  are formed about the circumference of this block for engagement with the rows of teeth formed on the bottom of the blocks  40  (see FIG. 2 b ). In one preferred embodiment, the diameter of this block is eleven inches. The teeth  150  extend the width of the block  146  preferably. Connected to opposite sides of the block are two circular stainless steel side plates  152 ,  154  which can have a thickness of ¾ inch. These plates are rigidly connected to the block by means of connecting screws  156 . An annular flange is formed about each plate  152 ,  154  at  158  in order to hold each bronze ring  64  in place. 
     The bottom end of the bracket plate  160  can be detachably connected to the front plate  18  by means of connecting plate  168  and suitable screws can be used for this purpose. A similar connecting plate  169  can connect the top of bracket plate  160  to the front plate. 
     The upper die rotating assembly  34  is adjustably mounted to the front plate  18  and the front bracket plate  160 . The adjustable mounting for the shaft  142  is substantially the same on each of the plates  18 ,  22  and  160  and therefore reference will be made only herein to the adjustable support on the front bracket plate  160 . As shown in FIG. 11, two straight, parallel guide plates  168 ,  170  are attached by screws  172  to the outer surface of the plate  160 . The guide plates have an inner edge  174  that projects over a rectangular opening  183 . These plates  168 ,  170  hold in a sliding fashion a rectangular support plate  176  having a central hole  178 . This plate  176  is movable up or down in the opening  183  formed in the plate  160 . The bearing  138  is mounted in the plate  176 . Bearing on the top edge of each plate  176  is a pressure pin  186  that extends downwardly from the end of a threaded pin or screw member  188  that is part of a die plate pressure gauge  190 . The preferred gauges  190  have a gauge dial (not shown) in their top end  192  which provides a pressure readout, this pressure being readable in psi. In a preferred embodiment, turning each pressure gauge in the clockwise direction puts further pressure on the top of the plate or slide  176 . This plate and the attached die assembly move against the pressure of two or more coil springs  194 , the upper ends of which can be accommodated in cylindrical cavities  195  formed in the bottom of the plate  182 . The bottom end of each spring presses against support surface  196  in the bracket plate  160 . As shown in FIG. 5, preferably three pressure gauges of similar construction are used in order to provide for fine adjustment of the position of the upper die assembly  34  and its shaft  134 . 
     The preferred gear arrangement for rotating the two casting drums  74 ,  76  at the same rate and at the same time by means for the single main drive shaft  96  will now be described with particular reference to FIGS. 1 and 2. The shaft  96  rotates the main drive gear  108  shown in FIG.  5  and outlined in dotted lines in FIG.  1 . This drive gear turns five identical idler gears  200  to  204  arranged in a horizontal row each of which is mounted on its own rotatable shaft  206 . These shafts are mounted by means of ball bearings in rear support plate  22  and in the front plate  18  as shown in FIG.  2 . Mounted on the last shaft  206  is a smaller gear  208  which rotates with the idler gear  204  and drives a larger gear  210 . This gear is mounted on rotatable shaft  212  that rotatably supports the casting drum  74 . It will be understood that the gear sizes are arranged to drive the casting drum at the required rotational speed upon rotation of the main drive shaft  96 . 
     In order to drive the casting drum  76 , the main drive gear  108  rotates a small idler gear  220  which then rotates three identical and in line idler gears  222  to  224 . The gear  224  has been omitted from FIG. 2 for sake of illustration. Idler gears  222  to  224  are supported on their respective shafts  226  which are rotatably supported in front plate  18  and rear plate  22 . Mounted on outer-most shaft  226  is a second, smaller gear  228  shown in outline in FIG.  1 . The gear  228  in turn drives a larger gear  236  which is mounted on a relatively large shaft  238  on which the casting drum  76  is mounted. Thus rotation of the main drive shaft  96  also rotates the casting drum  76  and at the same speed as the drum  74 . 
     Turning now to the means for dispensing tablets onto the gelatin strip  24 , the aforementioned bowl feeder  14  is able to deliver properly oriented pills to a number of tablet chutes  240  which extend downwardly along a slope from the outlet of the bowl feeder located at  242 . If there are eight recesses  42  formed in each die block, then there are eight separate chutes  240  which form eight sloping lines of tablets. The chutes are each sized to receive the preforms or tablets arranged in a single line and properly oriented and they are arranged side-by-side across the width of the die rotating assembly  36 . Preferably the chutes are made of a slippery, non-abrasive material so that the preforms slide easily therealong. The inclination of the chutes should be sufficiently great that the preforms will slide easily under the force of gravity but not so great as to put any undue weight on the preforms at the bottom of the chutes. The chutes extend downwardly to a location near the feeding location  30  at the top of die rotating assembly  36 . A first version of the tablet dispensing mechanism includes a tablet transfer device indicated generally at  250  in FIGS. 12 and 13. The illustrated device is able to move eight tablets  12  from a bottom section  252  of the chutes to the gelatin strip  24  which, at this time is supported by the die blocks  40 . This transfer device includes vacuum applying members  254  used to pick up tablets  12  from their respective chutes and a vacuum source  256  indicated only schematically in FIG.  12 . The vacuum source is operatively connected to the vacuum applying members by means of a vacuum line or hose  258  in which is mounted a suitable vacuum control valve  259 . The end of the line  258  can be connected to a horizontally extending tubular support member  260  which can extend substantially the length of the adjacent die blocks, as shown in FIG.  13 . The illustrated vacuum applying members include a rubber or rubber-like suction cup  262  sized to fit on top of the tablet  12  and a tubular metal cup connector  264  which is firmly connected to the bottom of the support member  260 . A plenum chamber  266  inside support member  260  is enclosed and is evacuated by means of the vacuum line  258 . Each vacuum applying member  254  is operatively connected to this plenum and accordingly vacuum is provided to each of the members  254  when required to pick-up a tablet. It will be appreciated that the valve  259  is provided to control the vacuum in the plenum and in the members  254  and air can quickly be supplied to the plenum and to the members  254 , when required, to release the tablets onto the gelatin strip. 
     The tablets  12  are each picked up by a respective vacuum applying member  254  at a tablet pick-up position indicated at  270  in FIG.  12 . This position is at the end of the tablet chute  240 . The ends of the chutes are closed by vertically extending end wall  272  but the top of the end section of each chute is open to permit the lifting of individual tablets at the bottom end of the chutes. It will be understood that the tablet transfer device causes the vacuum applying member  254  to go through the following operational sequence. The members  254  with their flexible vacuum cups are positioned directly above the bottom tablets and they are then lowered into contact with the end tablets. Preferably the vacuum cup  262  is applied to the front portion of the top of the tablet  12 . This is done to ensure that in the eventuality that the bottom tablet is cracked or split, the vacuum cup will always pick up at least the portion of the tablet at the very end of the chute, in other words, the portion adjacent to the end wall  272 . Thus, any unwanted build up of pieces of tablets at the bottom end of the chutes is largely prevented. 
     After the vacuum cup has been lowered to the top of the pill, vacuum is generated in the plenum chamber  266 , thus permitting the vacuum cup to grip the end tablet securely. The members  254  are then lifted together with the support member  260 , the end tablets being raised sufficiently to clear the end wall  272 . Then, the transfer device  250  causes the tablets with the support member  260  to be moved about one to one half inches horizontally and then the tablets and the member  260  are lowered so that the bottom of each tablet is just above the surface of the gelatin web. At the same time as the tablet reaches this position above the gelatin web, the vacuum in the plenum  260  is eliminated, thereby releasing the tablets  12 . It will be understood that the operation of the tablet dispensing mechanism is synchronized with rotation of the die blocks, particularly the blocks on the assembly  36  so that each tablet  12  is released over a respective one of the recesses of the blocks. 
     The transfer device  250  shown in FIGS. 12 and 13 is firmly mounted by means of screws  280  to the front plate  18  and comprises first and second air cylinder drive devices with the first drive device  282  providing substantially horizontal movement and the second drive device  284  providing substantially vertical movement. Each of these drive devices can be of standard construction for such devices and therefore a detailed description herein is deemed unnecessary. Briefly, the horizontally extending first drive device  282  includes a rigid slide table  286  containing an air cylinder or air chamber indicated in dashed lines at  288 . Slidingly mounted on this table is a rectangular support block  290 . A guide rail  292  extends longitudinally along the center of the slide table  286  and extends along a slot or groove having a similar cross-sectional shape in the block  290 . Movement of a piston member (not shown) in the air cylinder  288  causes the block  290  to move horizontally back or forth as required. The movable piston is connected to the block  290 . The second vertical drive device  284  is constructed in a similar fashion and includes a vertically extending slide table  294  which is rigidly mounted to the block  290  by means of connecting bolts or screws  295 . A rectangular support block  296  is slidably supported on the slide table and moves along a central, longitudinal rail  298 . Again, an air cylinder  300  is provided in the table  294  and a piston member  302  slidable in this cylinder is connected to the support block  296 . It will be understood that both of the drive devices  282  and  284  are connected to pressurized air hoses (not shown) which provide pressurized air to these drive devices in order to operate same. The support block  296  is firmly and rigidly connected to tubular support member  260  and is thus able to move the member  260  upwardly or downwardly when required. 
     An alternative form of tablet transfer device  410  is illustrated in FIG.  14 . This transfer device is described and illustrated in applicant&#39;s co-pending U.S. patent application filed January 29, 1999, Ser. No. 06/167,684 filed Jan. 2, 2001 the specification of which is incorporated by reference. Briefly, this transfer device includes an elongate pill chute  412  capable of holding a number of pills in vertically extending rows, a plunger mechanism (not shown) for temporarily engaging one of the pills in each chute, a rotatable feed roll  414  located adjacent a bottom end section of the chute, and a stop mechanism  416  for preventing temporarily downward movement of a bottom pill of each row of pills in the chute. The stops mechanism moves to a pill releasing position when the plunger mechanism is engaging one of the pills in the respective chute, this pill being located directly above the bottom pill in the chute. The stop mechanism prevents downward movement of the rows of pills when the plunger mechanism is moved to a position of disengagement from any pill in the chute. 
     Turning now to the construction of the scrap ribbon puller  84  illustrated in FIGS. 6 a  and  6   b , this device is driven by a gear train illustrated in FIG. 1 from the main drive shaft  96 . In particular, the main drive gear  108  drives a small idler gear  309  which in turn drives two similar, larger idler gears  310 ,  311 . The idler gear  311  drives small gear  316  which in turn drives a larger idler gear  314 , the purpose of which is described later herein. The gear  316  drives a scrap ribbon roller  324  shown in FIG. 6 a . It will be appreciated that this gear train is rotatably supported by shafts extending through and mounted in the front plate  18 . 
     Shown in FIG. 6 a  is front plate  18  through which extends drive shaft  320  on which the gear  316  is mounted. A pair of ballbearings at  322  support the shaft in the plate  18 . The scrap ribbon roller  324  is mounted on the shaft  320  for rotation therewith and this roller has a number of circumferential grooves  326  spaced evenly apart. These grooves are provided to permit any tablets that remain on the scrap ribbon to pass through the nip formed by the roller and adjacent spring loaded roller  328  (shown in cross-section). Small gripping teeth can be formed on the ridges  330  in order to enable the roller to hold onto and pull the scrap ribbon better. A nut  332  and suitable washers hold the roller in place on the shaft  320 . An annular spacer  334  helps keep the roller in position. 
     The upper spring loaded roller has grooves which are aligned with the grooves  326  and the ridges which form the grooves also have gripping teeth. The roller  328  is supported by means of a horizontal support bracket  336  connected to front plate  18  and four downwardly extending posts  338  about which extend coil springs  340  used to spring load the roller. The posts are threaded into the bracket  336  from below. On the posts are mounted two bearing holders  342 ,  344 . Roller bearings are mounted in the holders to rotatably support the roller  328 . It will be appreciated that the upper roller  328  acts to press downward on the scrap ribbon so that the scrap ribbon is firmly gripped between this roller and the roller  324 . Both these rollers can be made from aluminum. 
     The encapsulated tablets normally fall from the die blocks  40  after they pass through the nip. Those tablets which remain in the recesses in the die blocks are removed from the recesses by means of knock-out brushes  350  and  352  which sweep across their respective series of die blocks. The position of these brushes is indicated in FIG.  1 . 
     Separate gear trains can be provided to rotate each of the brushes  350  and  352 , the gear train for the upper brush  350  being driven by the idler gear  202  and the gear train for the lower brush  352  being driven by the gear  316 . The gear  202  drives a series of three small gears  400  to  402  with the last gear  402  being mounted on the same shaft as the brush  350 . The first gear  400  can also be used to rotate the oil roller  82 , if desired. The gear  316  drives a series of four gears  314  and  404  to  406  with the gear  314  being substantially larger than the other gears. The small gear  406  is mounted on the same shaft as the brush  352 . It will be understood that the rotatable shafts for both of these gear trains are mounted in the front plate  18 . 
     In order to ensure that the two gel strips  24  and  28  are heated to an adequate temperature for the encapsulation step, a heat light  354  can be located above the gel strip  24  at the location indicated in FIG.  1 . In one preferred embodiment, this location is about twelve inches away from the nip where the two gel ribbons meet. The heat light can be rigidly mounted on the front plate  18 . It will be appreciated that the heat light heats the gelatin strip  24  sufficiently so that it becomes sticky and pliable so that when the tablets are dropped onto the strip, they will stick to it and remain in place as they pass through the nip. A separate heat light can be provided to heat the strip  28  if the single light  354  is not sufficient for this purpose. 
     Mounted adjacent the perimeter of the lower die rotating assembly  36  is an electronic sensor  356  which per se can be of standard construction. This sensor accurately senses the rotational position of the die blocks  40  on the assembly  36 . This sensor is connected to a programmable logic controller (not shown) which also can be a standard type of controller suitable for controlling the operation of the above described tablet transfer device  250  and vacuum applying members  254 . This logic controller controls the operation of the first and second air cylinder drive devices  282  and  284  and the application of vacuum to the members  254  so that these devices will know when to pick up tablets from the bottom end of the chute, transfer them to the moving gelatin strip  24  and release them. 
     After the encapsulated tablets are formed by the rotating die assemblies, the tablets will normally fall under the force of gravity into a container  360  provided below the downwardly moving section of the scrap ribbon as shown in FIG.  1 . Tablets which remain stuck on the scrap ribbon will be able to pass through the scrap ribbon roller  84  because of the grooves formed therein. 
     In addition to the heat light(s)  354  for heating the gelatin strips, there can be provided other conditioning means for the gelatin strips so that they have a predetermined deformability and adhesivity to the tablets and to each other. For example, the entire apparatus  10  is best located in an air conditioned room so that temperature and humidity may be controlled to maintain the desired condition of the films. 
     A second embodiment for an apparatus for enrobing tablets in a gelatin layer is illustrated in FIGS. 14 to  16 . This apparatus  450  is similar in its construction in many ways to the apparatus  10  described above. Accordingly, only those features which differ from the apparatus  10  will be described in detail hereinafter. The apparatus  450  differs from the apparatus  10  in that it employs vacuum applied to the die blocks as they approach the nip of the rotary die assemblies in order to stretch portions of the gelatin webs and pull these portions into adjacent cavities in order to form tablet receiving cups or recesses in the gelatin web. In order to accomplish this vacuum step in the preferred apparatus  450 , there are two vacuum applying devices  452  and  454  each mounted adjacent a respective one of the two rotary die assemblies and connected to a vacuum source (not shown). Thus, as shown in FIG. 14, the vacuum applying device  452  is mounted adjacent the upper rotary die assembly  34 , on one side thereof while the vacuum applying device  454  is mounted adjacent the lower rotary die assembly  36 . As these two devices can be of similar or identical construction, only the device  36  is described in detail herein. The preferred vacuum applying device extends along a circumferential arc which ends at a location adjacent the nip  32  or which extends a short distance beyond the nip as illustrated in FIG. 14, although vacuum is not applied to the die blocks beyond the nip itself. Each vacuum device has a primary vacuum applying passageway  456  that extends along the length of the device and is operatively connected to vacuum applying passageways in the plastic blocks when they are rotated along and next to the vacuum applying device. A threaded metal connector member  458  can be threaded into the device  454  at the open end of the passageway  456  to permit attachment of a vacuum hose  460  which extends to a suitable vacuum source that can be of standard construction. 
     Each vacuum applying device  452 ,  454  preferably comprises a substantially flat member having a friction reducing coating  462  on the inner side thereof (see FIG.  16 ). The preferred coating is tetrafluoroethylene polymer such as that sold under the trade-mark TEFLON and preferably the material is pharmaceutical grade Teflon. The coated inner side engages a flat side  464  of the rotary die assembly and is slidable thereon during rotation of the die assembly. Also the preferred vacuum applying device is made with two adjacent, flat plates  466  and  468  which can be securely attached to each other in any suitable manner such as by welding or by adhesive. These two plates can be seen clearly in FIG. 16 which is on a larger scale. The primary vacuum applying passageway  456  is formed in the innermost plate  466  with the outer wall of this passageway being formed by the outer plate  468 . Two or more coil springs  470  are preferably used to engage an outer side of each vacuum applying device  452 ,  454 , these springs acting to bias the substantially flat device towards and into engagement with the flat side  464  of the rotary die assembly. Each spring  470  extends around a short support pin  472 , one end of which can be mounted in the outer plate  468 . Each pin  472  is free to slide in a sleeve guide  474  which is mounted at one end of cylindrical cavity  476  formed in the bracket plate  160 . As the sleeve guide  474  is formed with an inner end flange, it cannot pass out through a circular opening  480  formed in the bracket plate  160 . It will thus be seen that the inner end of each spring  470  applies a biasing force against the outer surface of the plate  468 , thus keeping the vacuum applying device pressed against the flat side of the rotary die assembly. Also, a vacuum passageway  482  is formed in the adjacent rotary die assembly beside the primary vacuum passageway  456 , thus permitting vacuum to be applied to the modified plastic die blocks  484 . 
     Turning now to the construction of these modified die blocks  484 , it will be appreciated that these die blocks can be similar in their construction to the die blocks  40  described above and only the differences in their construction will be described hereinafter. These die blocks have a number of tablet receiving recesses  486 , each of which has a bottom  488  and at least one side wall  490  forming a substantially enclosed recess with an open top. Each block  484  has one or more vacuum applying passageways opening into the recesses  486 . In the illustrated preferred block, there is one long vacuum applying passageway  492  that extends from an open end adjacent the short vacuum passageway  482  to almost the opposite end of the block. This long passageway is connected by means of a number of short passageways  494  to the recesses  486 . It will thus be seen that these passageways  494  and  492  are connectible to the aforementioned vacuum source during operation of this apparatus and, in particular, during the time period when the blocks are approaching the nip  32 . In the preferred illustrated embodiment, one end of the long passageway  492  extends through one of the three cylindrical protrubences at the end of the block, preferably the central protuberance  58 .It will be understood that the block  484 , like the first described block, is provided with laterally projecting connecting members formed on two opposite ends of the die block for connecting the die block to connecting members, preferably in the form of the described connecting rings, used to connect the die block to a number of other similar die blocks. 
     As illustrated in FIG. 14, in the preferred embodiment, the lower vacuum applying device  454  initially provides vacuum to the die blocks at a location  500  near the tablet dispensing mechanism. Thus, as the tablet is delivered to the gelatin web  24 , a cup or recess is quickly formed in the web at each recess in the passing die block. In this way, the tablets are held securely in place in each of the respective cavities as they are rotated into the nip  32 . In other words, each dispensed tablet is held in a stretched portion of the gelatin strip as it moves with the strip into the nip. As soon as the tablet reaches the nip and is covered on both sides with a gelatin layer, the vacuum is released or removed so that it will not interfere with the completion of the enrobed tablet. 
     If desired, pressurized air can be used to help remove the covered tablets from the cavities in the die blocks after they are enrobed at the nip. This pressurized air can be introduced into the cavities of the die blocks through separate end portions of the aforementioned passageways  492  and  494 . The pressurized air can be introduced into the die blocks with the use of either the vacuum employing devices  452  or  454  or by means of separate, pressurized air applying devices constructed in a similar manner to the devices  452 ,  454  but substantially shorter. In the case where the vacuum applying devices  452 ,  454  are used, a pressurized air hose can be attached to each of these devices in the tail region  502  indicated in FIG.  14 . It will be understood that whether or not pressurized air is used, the vacuum applying passageway  456  is terminated adjacent the nip, that is at the point  504 . The portion of each passageway  456  that extends beyond the passage closure or passage end at  504  can be used for the application of pressurized air to the cavities. If the use of pressurized air is not required, then the tail section  502  of the vacuum applying device need not be provided and openings can simply be provided in the circumference of the rotary die assembly to permit air to quickly enter the passageways  492  in the blocks, thereby preventing any vacuum in the block cavities. 
     It will be further appreciated that it is possible to omit the upper vacuum applying device  452  entirely, if desired, and to only apply vacuum to the blocks of the lower rotary die assembly  36 . With this version, the upper web  28  will remain relatively flat over the top of the die cavities until it reaches the nip  32  where the introduction of the top halves of the tablets will cause the upper gelatin web to be stretched in each cavity. It is also possible, although less preferred, to apply a vacuum only to the upper rotary die assembly by means of the vacuum applying device  452  and to have no vacuum applied to the blocks of the lower rotary die assembly. In such an embodiment, one would simply rely upon the tackiness of the lower gelatin web  24  to hold the tablets in place over their respective cavities as they move from the tablet dispensing mechanism to the nip. 
     It will be appreciated by those skilled in the art that various modifications and changes can be made to the described apparatus for enrobing tablets and to the described die blocks without departing from the spirit and scope of this invention. For example, instead of employing the tablet dispensing mechanism illustrated in FIGS. 12 and 13, one could employ known tablet dispensing mechanisms such as that illustrated in FIG. 26 of U.S. Pat. No. 5,459,983, the specification and drawings of which are incorporated herein by reference. In this known dispenser, the preforms pass through chutes and an eccentric cam mounted on a drive shaft extends into each tubular chute through a side opening and contacts a tablet in the chute. The cam contour is defined in combination with the rate of rotation of its shaft to engage a tablet in the chute each time a row of recesses in the die blocks  40  reaches a desired position and to drive the tablets in each chute a desired distance along the chutes, this distance being sufficient to permit the end tablet in each chute to drop out of the chute and onto the passing web. A resilient element, ie. a leaf spring, is mounted at the bottom end of each chute to hold the lowermost tablet in the chute until the aforementioned cam operation forces it past the resilient element. 
     As indicated, many variations of this invention will suggest themselves to those skilled in this art. Accordingly, all such modifications and changes as fall within the scope of the appended claims are intended to be part of this invention.