Abstract:
A rotary deblistering apparatus is described. It comprises a rotatable drum having plurality of circumferential pack holding means each adapted to hold and retain a blister pack. The drum can rotate to locate the pack holding means at a plurality of peripheral work positions including a pack loading position, a pack deblistering position, and a pack detachment position. The blister packs can be loaded onto the drum through a loading means, preferably the loading means has a storage magazine able to supply a continuous number of packs to the drum. For a peelable pack, prior weakening or cutting of the backing of the pack may be necessary or desired. Such action could be carried out at the pack deblistering position. Alternatively, there is a prior weakening and/or cutting position around the drum.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This Application is the U.S. National Phase Application of PCT International Application No. PCT/GB99/03618 filed Nov. 02, 1999, and published under PCT Article 21(2) in English. 
     The present invention relates to a rotary deblistering apparatus. 
     DESCRIPTION OF RELATED ART 
     Blister packs for pharmaceutical tablets are generally either “push through” packs, where manual pushing of the tablet will eject it from the pack through the backing, or “peelable” packs. Peelable packs are intended to be child-resistant, and require the backing to be ‘peeled’ away before the tablet is accessible. Deblistering of tablets from a push through pack is generally carried out by passing the packs through rollers. Because of the more sealed nature of the peelable pack, deblistering of tablets from such packs is often not possible simply through rollers, and linear or batch processing has been necessary. 
     BRIEF SUMMARY OF THE INVENTION 
     According to one aspect of the present invention, there is provided a rotary deblistering apparatus comprising a rotatable drum having a plurality of circumferential pack holding means, each adapted to hold a blister pack, wherein the drum is rotated to locate the pack holding means at a plurality of peripheral work positions including a pack loading position, a pack deblistering position, and a pack detachment position. 
     The multiplicity of pack holding means on the drum, and the drum&#39;s rotational ability, allow more than one pack to be handled at the same time, increasing the rate of deblistering of the apparatus compared with prior art static deblistering apparatus. Indeed, the present invention is able to provide a continuous operation. 
     The rotational movement of the drum is preferably indexed, and the drum is preferably stationary at each work position. 
     The drum may have any number of pack holding means, and be of any suitable size and shape. In one embodiment of the present invention, the drum has the same or similar number of pack holding means as work positions around the drum. 
     Preferably, the drum is vertically arranged. More preferably, the pack loading position is located wholly or substantially above the drum, to allow gravity to assist loading of a blister pack onto the drum. Similarly, preferably the pack deblistering position and/or the pack detachment position are located wholly or substantially below the drum, to allow gravity to assist the ejection or detachment of the tablets and/or deblistered pack from the drum. 
     The blister packs can be loaded onto the drum through any suitable loading means. The loading means preferably has a storage magazine able to supply a continuous number of packs to the drum. The loading means could also have a pack selection means to assist individual loading of each pack onto each pack-holding means. The magazine and/or pack selection means is preferably able to deal with curled packs, which are often the most problematic with prior art deblistering apparatus. The pack selection means preferably involves opposing means moveable between pack-edge support and release positions, generally through reciprocal linear and/or rotational motion. Such means include pins, flanges, discs, etc. 
     A blister pack can be held by a pack holding means using any suitable attachment means, including vacuum, mechanical fastening aids, and/or possibly simple friction fit. 
     The pack holding means are preferably adapted to match the shape, size and configuration of the design of the pack to be deblistered. The drum also preferably allows each pack holding means to be rapidly and easily changed for different pack designs. The changeability is preferably tool-less, i.e. possible without the need for use of any separate tools such as spanners, keys, screwdrivers, etc. 
     The deblistering of the tablets from a pack held on the drum can be carried out using suitable mechanical or pneumatic force, eg air, pins, etc. Direct force is generally sufficient for deblistering a push through pack. For a peelable pack, prior weakening or cutting of the backing of the pack may be necessary or desired. Such action could be carried out at the pack deblistering position. Alternatively, there is a prior weakening and/or cutting position around the drum. Such a position could be permanently located, but by-passable or inoperable when the present invention is being used for push through packs. 
     The pack holding means may be moveable at one or more the work positions to effect the operation on the pack thereat. Alternatively, one or more of the relevant operative means at each work position is moveable when operating on the pack held on the drum. 
     The present invention may be used for any shape, size and design of blister pack. 
     According to a second aspect of the present invention, there is provided a method of deblistering one or more blister packs using a rotary deblistering apparatus as herein described, wherein the pack is loaded onto a pack holding means at the pack loading position, rotated to the pack deblistering position where the tablets are forced out of the pack, and the empty pack is then rotated to the pack detachment position where the pack is detached from the pack holding means. 
     In one embodiment of the method-of the present Invention, the backing of the pack is wholly or substantially cut or weakened at a further work position around the drum. 
    
    
     DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     An embodiment of the present invention will now be described by way of example only and with reference to the accompanying drawings in which: 
     FIG. 1 is a front view of a rotary deblistering apparatus according to the present invention; 
     FIG. 2 is a side view of the apparatus of FIG. 1; 
     FIG. 3 is a top view of a first pack plate used in the apparatus of FIG. 1; 
     FIG. 4 is a cross-sectional side view of the pack plate of FIG. 3; 
     FIGS. 5 a  and  5   b  are plan views of a first pack selection means for use in the apparatus of FIG. 1; 
     FIGS. 5 c  and  5   d  are side views of the pack selection means in FIGS. 5 a  and  5   b  respectively; 
     FIGS. 6,  7  and  8  show a top view and first and second cross-sectional side views of a second pack plate for use in the present invention; and 
     FIG. 9 is a side cross-sectional view of a second pack selection means for use in the apparatus of FIG.  1 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to the drawings, FIGS. 1 and 2 show a rotary deblistering apparatus involving a drum  2  rotatable about a central axle  4 . The drum  2  has four pack holding means  6  symmetrically located about its circumference. 
     Each pack holding means  6  has a pack plate  8  which is shown in more detail in FIGS. 3 and 4. The plate  8  has a flat top surface  10  and a number of pockets  12  depending therefrom. The shape, number and configuration of the pockets  12  is designed to match the shape, number and configuration of the blisters on the blister pack or packs to be deblistered. An aperture  13  extends from the bottom of each pocket  12  and through the plate B to a hollow insert  14  in the base of the pack plate  8 . 
     Behind each pack holding means  6  is piping (not shown) extending back to intermediate slip plates  20  between the rotating drum  2  and a stationery support wall  24 . The slip plates  20  are preferably plastic, and may be urged or biased together to maintain an air seal therebetween despite wear. 
     Using grooves and apertures in the slip plates  20 , either an air vacuum or an air over-pressure can be directed through each piping to the base of each pack plate  8  and then to the pockets  12 . One or more bleed or pressure valves may be necessary around the apparatus to ensure equilibrium of pressure or vacuum, or to at least avoid over-pressure or over-vacuum. The pressure or vacuum can be supplied by any suitable pump means known in the art. 
     The pack plate  8  has, a shoe  16  on each side to match opposing shoulders  18  attached to the drum  2  at each pack holding location. Thus, if it is desired to deblister a pack having a different blister shape, the pack plates  8  can be rapidly and easily removed onto and off the drum  2  using a simple sliding action to fit new plates with the required new pocket shape, etc. A final fastening means could be used to hold each pack plate  8  securely on the drum  2 . The base of each type of pack plate should be similar. 
     The rotational movement of the drum  2  is indexed, such that the drum  2  is stationery when the pack-holding means  6  are aligned with the following work positions. 
     In the apparatus shown in FIGS. 1 and 2, there are four work positions. Uppermost is a pack loading position A. On the right in FIG. 1 is a pack cutting position B. Lower most is a pack deblistering position C, and on the left in FIG. 1 is a pack detachment position D. 
     The pack loading position A involves a pack loading means  26  with an upright magazine  27  in which a number of blister packs could be stacked, either prior to operation of the drum  2  or continuously. The operation at the base of the pack loading means  26  is shown in more detail in FIGS. 5 a-d.    
     FIGS. 5 a - 5   d  show a pack selection means  26  comprising opposing pack edge semi-circular blades  28 . The blades a  28  are rotatable about axes  29 , using reciprocal ram and piston means  30  attached at one corner of the blades  28 . Each blade  28  has generally arcuate lower and upper front edges  34 , cutaway  31  at different positions around the front edge. The blades  28  are moveable to move the edges  34  between (lowest) pack-edge overlapping positions, shown as “Position  1 ”, and (lowest) pack-edge avoiding positions, shown as “Position  2 ”. 
     FIG. 5 c  shows two stacked blister packs  32   a  and  32 b (generally “ 32 ”). The edges of the lowest pack  32   a  are held by the lower edges of each blade  28  above which the upper edges are cutaway. By rotation of the blades  28  from Position  1  to Position  2 , the lower edges are drawn away from the pack edges, so as to release lowest pack  32   a  to fall by gravity onto an aligned pack holding means  6  therebelow (not shown). Simultaneously, and as shown in FIG. 5 d , the offset extended part of the upper edge of each blade  28  is rotated into an overlapping position underneath the pack edges of the next blister pack  32   b . Reverse motion of the blades  28  allows the now-lowest pack  32   b  to be held by its pack edges by the lower extended edges of the blades  28 , ready for loading into the next pack holding means  6  as it becomes available. 
     In use, blister packs  32  are fed into the magazine  27  to be loaded around the drum  2 . Vacuum is applied to the pack holding means  6  when at the pack loading position A to assist loading of a pack  32  onto the relevant pack plate  8 . The pockets  12  of the plate  8  accommodate the blisters of the pack  32 . The drum  2  is then rotated 90° until the held pack  32  is aligned with the cutting position B. Where the pack  32  is a push through pack, no cutting may be necessary, such that the pack  32  is not acted upon at this stage. Where the pack  32  is a peelable pack, a cutting tool  36  can be directed against the backing of the pack  32  to wholly, or preferably substantially, cut the backing around each blister. 
     Meanwhile, a second pack  32  is loaded onto the following pack-holding means  6 . 
     The drum  2  is then rotated 90° again until the first pack  32  is aligned with the pack deblistering position C. With continuing vacuum applied to the rear of each pack plate  8  as described above, the pack  32  is retained on the plate  8  even at position C. 
     At position C, a backing plate  38  is raised against the backing of the held pack  32 . The backing plate  38  has apertures aligned with the blisters of the pack  32  and the pockets  12  of the pack plate  8 . With the backing of the pack  32  thus firmly held between the plates  8 ,  38 , the tablets can be forced out of the pack and collected below position C. The tablets could be pneumatically blown out. The backing plate  38  is then retracted. 
     Meanwhile, the following blister pack could be being out at position B, and a third pack loaded at position A. 
     With further 90° rotation of the drum  2 , the empty pack  32  is ready for detachment at position D. Using a blast or pulse of air through the piping behind the pack plate  8  instead of vacuum, the empty pack is blown away from the drum  2 . The discarded packs could be collected in a suitable bin. 
     Continuous rotation of the drum  2  clearly allows for continuous loading, optionally cutting, deblistering and detachment of similar blister packs. 
     In one modified arrangement, second pack plates  46  as shown in FIGS. 6,  7  and  8  could be used. These pack plates  46  are similar to the first pack plates  8  described above, in that they have a smooth top surface  48 , and a number of pockets  50  depending therefrom to suit the shape, number and configuration of the blisters on the blister pack or packs to be deblistered. 
     The top plate  52  of the second pack plate  46  fits with a pack holding means, eg the pack holding means  6  in FIG. 1 etc, to form a sealed enclosure, such that again vacuum can be used to retain the blister packs on the top plate  52  during the majority of the working cycle of the deblistering apparatus. The second pack plates  46  could be held in the pack holding means by simple catches or bolts etc. 
     Attached to the top plate  52  via a shoulder bolt  54  is a bottom plate  56 , biased away from the top plate  52  by two intermediate springs  58 . Upstanding from the bottom plate  56  are a series of eject pins  60  aligned with the pockets  50 . The pins  60  are fixed to the bottom plate  56  by holding screws  62 . 
     In use, the second pack plate  46  provides an alternative arrangement for ejecting the tablets from a blister pack, especially stronger eg. push through packs. When the blister pack has reached position C as shown in FIG. 1, a backing plate is still brought against the free side of the blister pack to firmly hold it as before. However, a mechanical force, eg. a hydraulic ram or piston, can now be used to impact the base of the bottom plate  56 , and force it towards the top plate  52  of the second pack plate  46 . In doing this, the pins  60  will travel up to and through the pockets  50 , and mechanically push out the tablets from the held blister pack. A stop bar  64  limits the possible inter-plate distance. 
     This arrangement provides a usually stronger force of ejection, and possibly a more even force of ejection across all the pockets  50 . The strength of each blister is therefore less important. There is also the potential with the ejection by air pressure that the bursting of any one blister will effectively nullify or weaken further air pressure action. Use of mechanical pins avoids this. 
     In a second possible modification to the apparatus, loading means as shown in FIG. 9 could be used. FIG. 9 shows four blister packs  78 . The lowest pack  78   a  is held by two sets of lower pins  80  (one of each set is shown). Above these are two sets of upper pins  82 , generally held (but not shown) in a retracted position. When the drum  2  has aligned a pack holding means  6  below the stack of blister packs  78 , the upper pins  82  are extended (as shown) to hold the penultimate pack  78   b  (and thus all higher packs), whilst the lower pins  80  are retracted to allow the bottom pack  78   a  to fall by gravity onto the pack holding means  6 . The lower pins  80  are then re-extended, and the upper pins  82  retracted, to allow the next pack  78   b  to be the next loadable pack. 
     The lower and upper pins  80 ,  82 , like the blades  28  in FIGS. 5 a - 5   d , have the added advantage that they are able to accommodate curled or otherwise non-flat blister packs by acting on the edges of a pack. 
     In a third possible modification of the apparatus, the mechanism for loading blister packs onto the apparatus at the pack loading position A could involve two or more helical screw or augers inclined towards the pack loading position. The substantially vertical screws are locatable on opposite sides of the blister packs, and converge towards the pack loading position, such that by rotation, the edges of the packs are met with the edges of the screws, and then guided downwards towards the pack loading position A. With the slight downward convergence of the screws, once the edges of the blister packs are located within the grooves of the screws, they will be continuously guided downwards towards the pack loading position A. The use of such screws may provide better and smoother catching of the edges of blister packs, and result in less rejection of misshaped blister packs, ie packs which may be curled or otherwise non-flat. The rotating screws also provide a continuous mechanism for regularly downloading the blister packs into the pack loading position A, without requiring separate or discrete pack loading operations. 
     The apparatus of the present invention as shown in FIG. 1 can be located with a box or cover  40 , which could also be wholly or substantially sealed to minimize the possibility of contamination during the deblistering operation. FIG. 2 also shows the apparatus located on a mobile platform  42 , making it easily relocatable. The motors and valves for the vacuum to the drum  2  and for the pneumatics for the operable work stations are located in a rear cabinet  44 . 
     It is considered that the present invention could deblister fifty or more average peelable blister packs per minute, compared with the common maximum of twenty peelable packs per minute with batch or individualised prior art apparatus. The present invention can also deal with curled packs, which often block or jam prior art apparatus. 
     The present invention furthermore has the ability for tool-less changing of its plates to fit different sized, shaped or configured blister packs. Thus, the number of each type of pack to be deblistered, whether it be one or a thousand or more, makes little difference to the time required for deblistering. 
     The present invention also avoids the use of belts or chains to convey the blister packs between the work positions, decreasing the possibility of any contamination of the tablets from oil or grease etc.