Abstract:
Automatic feeding machines are commonly used for filling blister packs with items of product such as pharmaceutical dosage forms. These machines are usually designed for the handling of a specific shape and sized product item. Handling of different shaped items requires expensive re-tooling of all the product item contact components. The invention allows a single feeding machine to be quickly configured for use to handling a wide variety of item sizes/shapes. A machine ( 21 ) has a tray ( 36 ) defining a series of tapered channels ( 40 ) and a container ( 22 ) slideably mounted above the tray. A wall of the container and the channels together define apertures into each channel through which items of product pass out of the container. Sliding movement of the container across the planar tray surface ( 38 ), along and over the channels, allows the size of the apertures to be adjusted depending upon the size of the item of product to be handled, using the same components.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This national stage application claims the benefit under 35 U.S.C. §371 of International Application No. PCT/GB008/003133 filed on Sep. 15, 2008, entitled PRODUCT FEEDING APPARATUS, which in turn takes its priority from British Application No. 0717980.7 filed on Sep. 14, 2007 and all of whose entire disclosures are incorporated by reference herein. 
     BACKGROUND 
     The present invention relates to product feeding apparatus suitable for delivering items of product into pockets of a blister type pack and, in particular but not exclusively, for the feeding of pharmaceutical dosage forms into pockets of pharmaceutical blister and patient packs. 
     Patient packs are trays defining an array of pockets for holding medication for a patient, hermetically sealed by a film. Typically the pockets, which are sized to accommodate a variety of product types, hold a dose of medication to be taken on a particular day or time. For example, a pack may have an array of pockets arranged into four columns by seven rows wherein each column represents one week of a four week period and the rows represent days within each week. If medication is needed to be taken multiple times a day, e.g. with breakfast, lunch and dinner, three packs would be assigned to the patient for the four week period wherein each pack contains the medication for the respective dose for breakfast, lunch and dinner. 
     Patient packs are particularly useful in environments such as nursing homes and prisons for the dispensing of medication to residences with ongoing or repeat prescriptions. The prescription, in the form of tablets, capsules, caplets or other discrete dosage forms, is made up in advance at a pharmacy, hand filled into the pockets of the patient pack, sealed, marked with the patient&#39;s details and sent to the patient&#39;s residence. The medication can then be taken by the patient as directed on the pack. This system obviates the need for institutions, such as those mentioned above, to employ staff who are authorised to dispense medication. 
     Automatic filler machines are commonly used for the filling of specific product items into blister packs. The process for each product is heavily tailored with the blister pack and filling machining being specifically designed to hold and handle the dimensions and form of the particular product item. Modification of the machines to handle a different shaped or sized product requires expensive re-tooling of all the product contact components. It is thought that in excess of 300 sets of re-tooled components would be needed for a feeding machine to handle all of the known discrete dosage forms of pharmaceutical product. 
     As a consequence of the above, automatic feeders have been considered impractical for use in filling patient packs where a wide variety of different product forms are handled, often in relatively small quantities at a time. 
     SUMMARY OF THE INVENTION 
     In accordance with one aspect of the present invention, there is provided product feeding apparatus for delivering items of product to one or more outlets from which they may be delivered into pockets of a blister type pack or other packaging or receptacle, comprising: 
     a surface defining one or more channels arranged to guide items of product and where the width and/or depth of the channel increases towards an exit of the channel; 
     a wall adjacent to the surface; 
     wherein the wall and one or more channels cooperate to define at least one aperture through which items of product pass towards the exit of the channel; 
     and wherein the size of the aperture is adjustable by movement of the wall and/or surface relative to the other. 
     The invention enables a single feeding machine to be used to fill a package such as a blister pack with product items having a variety of product forms, such as tablets, caplets, capsules, hardgels and softgels in a wide range of sizes and shapes, without the need for numerous expensive sets of tooled components 
     A preferable embodiment of the invention comprises a repository for holding loose items of product. The wall may be associated with the repository or more favourably form part of the repository. Ideally, the wall is arranged to move transversely across the surface which may be achieved by slideably mounting the repository above the surface. If the wall is moved along the channel in a direction of increasing or decreasing channel width or depth, the aperture size may be correspondingly increased or decreased using the same set of components. 
     It is preferred that the channels of the surface be tapered over at least a part of their length. It is preferred that the channels be sloping downwardly from the horizontal over at least a part of their length. It is preferred that the surface be agitated by vibrating means so as to shake items of product along the channels towards their exits. 
     Movement of the items of product out of a channel before the intended exit point may be prevented by a restraining means which preferably takes the form of a restraining member supported above the open channel. The restraining member may be supported such as to be inclined at an angle relative to the surface. This angle may correspond to the slope of the channel, or may be steeper, thus causing the channel depth to decrease towards its exit. 
     The apparatus may also comprise a discharge gate mechanism associated with each channel to control delivery of items of product from the channel exit into pockets of the blister pack or other receptacle. It is preferred that the gate mechanism comprises at least two sequential gates defining a product item delivery compartment between them. At least one of the gates, particularly an entry gate to the delivery compartment, may be associated with a restraining member. It is further preferred that a gate associated with a restraining member is formed as a lip on the restraining member which protrudes into the channel. The gate may be actuated by making the restraining member moveable relative to the channel. Alternatively, the gates may be separate from the restraining members. 
     So as to control the number of items of product being retained in the delivery compartment between the two gates at one time, it is preferred that the gate mechanisms of the sequential gates for each channel are operable independently from one another, that at least the delivery compartment entry gate mechanisms for separate channels are operable independently from one another, and that the spacing between the gates is adjustable to control the size of the compartment. 
     To aid in limiting or controlling the flow of items of product, the repository may further comprises a baffle. Product sweeping means may be provided to sweep product items over the surface containing the channels, in order to limit build-up of product on the surface. Such sweeping means may be provided before the at least one aperture, preferably adjacent the wall and inside the repository. 
     It is further preferred that the repository, restraining means and gate mechanism are supported on one or more carriages so as to be slideably moveable. The carriages may be moveable along rails, and provided with clamps and position indicators so that their positions for particular product items may be reproduced. 
     Other aspects of the invention are set out in the following specific description and in the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Two embodiments of the invention will now be described by way of example and with reference to the following figures in which: 
         FIG. 1  is an isometric view of a first embodiment of a filling machine for filling discrete items of pharmaceutical product into patient packs; 
         FIG. 2  is an enlarged isometric view of the hopper (repository) and tray (surface) of  FIG. 1  in cross section; 
         FIG. 3  is a side view cross section of the filling machine; 
         FIGS. 4A and 4B  are isometric views to illustrate movement of the hopper across the tray to adjust the aperture size; 
         FIGS. 5A and 5B  are cross section views of a tray in conjunction with preferred profiled restraining bars; 
         FIG. 6  is an isometric view of a second embodiment of a filling machine for filling discrete items of pharmaceutical product into patient packs; 
         FIG. 7  is an isometric view of the filling machine of  FIG. 6  from a different viewpoint and with the top partially lifted; 
         FIG. 8  is an enlarged view of a portion of  FIG. 7 ; 
         FIG. 9  is a view corresponding to  FIG. 6  but in longitudinal cross section; 
         FIG. 10  is an enlarged view of a portion of  FIG. 9 ; 
         FIGS. 11A and 11B  are isometric views to illustrate movement of the repository across the surface to adjust the aperture size; 
         FIGS. 12A and 12B  are respectively an end elevation and an isometric view illustrating the co-operation of a restraining member with channels formed in the surface of a delivery tray; 
         FIG. 13  is an isometric view from the exit end and underneath of the underside of the delivery tray of  FIGS. 12A and 12B ; 
         FIG. 14  is an elevation corresponding to  FIG. 12A  showing an alternative delivery tray for a different size and shape of product item; and 
         FIG. 15  is an isometric view showing a delivery chute, with its cover removed, leading from the machine to a blister pack. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Referring to  FIGS. 1 to 3  there is shown a filling machine  1  comprising a repository for discrete items of pharmaceutical product, formed of an inverted truncated pyramid shaped hopper  2 . The hopper  2  has an open bottom and a lower portion of its front wall is formed from a rubber strip member  2 A secured by clamp  2 B. The hopper  2  is slideably supported via a carriage  7  on slide rails  3  which are in turn supported on a frame  4 . 
     A product feed tray  5  has a top surface which defines seven parallel open-topped channels  5 A running to an edge (discharge end)  5 B of the tray substantially along the length of the tray  5 . The channels  5 A have a V-shaped, including flat bottom V-shaped, cross section. The width and depth of each channel  5 A tapers gradually along its length from a width and depth of zero in a hopper base region  5 C of the top surface of the tray  5  to a maximum width and depth, and is thereafter constant to an exit end of the tray from which product will, in use, be discharged. Throughout the channel&#39;s length, its width W is greater than its depth D so as to minimise jamming of an item of product in the channel  5 A. The bottoms of the channels slope at a shallow angle, typically up to ten degrees and preferably from four to eight degrees to the horizontal, downwardly towards the exit end. 
     The tray  5  is positioned such that the hopper base region  5 C is directly below the hopper  2  so as to form a base of the hopper  2 . The tray  5  is also orientated such that the channels  5 A extend under the front wall  2 A of the hopper  2  forming seven apertures  2 C defined between the channel  5 A walls and the bottom edge of the front wall  2 A. The tray  5  is supported by an electromagnetic shaker  6 , of a kind known as a vibrating means in the blister pack filling art. The shaker  6  is itself mounted on frame  4 . 
     As can be seen in  FIGS. 4A and 4B , the carriage  7  enables the hopper  2  to be slid along slide rails  3 , horizontally across the top surface of the tray  5 , parallel with the channels  5 A. Movement of the hopper  2  towards the discharge end  5 B of the tray  5  causes the aperture size  2 C to increase as a consequence of the enlarging width W and depth D of channel  5 A. Conversely, movement away from the discharge end  5 B of the tray  5  causes a reduction in the aperture  2 C size. Movement of this kind allows the apertures  2 C to be sized depending upon the product held within the hopper  2 , such as to allow only a single item of product to pass out of each aperture of the hopper at a time, according to the product item dimensions. 
     Also mounted onto carriage  7  in front of wall  2 A is a restraining mechanism comprising seven solenoid linear actuators  8 , actuating rods  8 A and restraining bars  9 . The restraining bars  9  are supported directly above the centreline of each channel  5 A and inclined at an angle so that the lower surface  9 A of each retaining bar is closest to the tray  5  at the discharge end. Formed at the free end of each bar  9  is a lip  9 B which protrudes into the channel  5 A. The lip  9 A acts as a gate for the control of items of product along each channel  5 A. Each lip/gate  9 B may be raised or lowered independently of the other six gates  9 B. 
     Because the restraining mechanism and hopper  2  are mounted on the same carriage  7 , both can be moved across the tray  5  whilst maintaining the horizontal relationship between the apertures  2 C and restraining bar inlets  9 D. 
     Slide rails  3  also support a second carriage  10  independently moveable from the first carriage  7 , onto which is mounted a laser sensor  11  associated with each channel  5 A, a discharge gate  12  and a solenoid operated linear actuator  13 . 
     Laser sensors  11  are arranged to detect the presence of an item between the gates  9 B and  12 . Each sensor has a complementary reflector which is formed from a polished base portion of the V-shaped channel. The sensors  11  and solenoid actuators are controlled by a programmable logic control system also not shown. 
     The discharge gate  12  is composed of a machined plate defining seven protrusions  12 A and arranged so that each protrusion sits within a channel  5 A at the discharge end  5 B of the tray  5 . The protrusions  12 A may be raised and lowered in unison by the solenoid actuator  13  to control the discharge of items of product from the tray  5 . 
     Supported by the frame at the discharge end of the tray  5  is a vertical delivery box  14  containing seven individual chutes whose inlets are aligned with each of the channels  5 A. The width and depth of each chute at its outlet end is equal to the width and depth of a patient pack pocket (not shown) which are positioned at the outlet end of the chutes  14 A for filling. 
     The feeder machine  1  is enclosed within a clear polycarbonate cover (not shown) secured with quick release fasteners to the main frame. 
     Before operation, the carriage  7  holding hopper  2  and the restraining mechanism are slid along slide rails  3  so as to tailor the aperture size  2 C to the size/shape of the product item. The height of the restraining bars  9  above the channel may also be adjusted to ensure that the product items do not climb above one another when queued along the channel and so as to ensure that gate  9 B operates effectively. 
     The second carriage  10  may also be slid along rails  3  so as to ensure that the discharge gate  12  and lip  9 B are separated by a distance corresponding to the size of a single item of product, thus forming a delivery compartment. 
     In use, loose items of product are fed into the top of hopper  2  and retained between the walls of the hopper  2  and tray  5 . The electromagnetic shaker  6  agitates the tray  5  to incite the items of product to move generally down the slope towards the discharge end of the tray. Rubber wall  2 A generally prevents the passage of items of product out of the hopper  2 . However, items which have fallen within the channels  5 A are able to pass out through apertures  2 C one at a time. 
     The items move along the channels until they reach lip  9 B. Restraining bar  9  ensures that the queue of items of product along the channel between gate  9 B and aperture  2 C remain in single file by preventing ‘climbing’ of the items on top of one another. 
     Upon a command from the control system the solenoid actuator  8  raises lip  9 B to allow passage of an item through into the delivery compartment. The distance between the discharge gate  12 A and lip  9 B has been pre-set so that only a single item of product can reside between the two at a time. The presence of an item between the gates  12 A and  9 B is sensed by sensor  11  which causes the actuator  8  to lower the lip  9 B to prevent any further items from entering the gate. 
     Once an item of product is contained between each of the pairs of gates, the control system instructs the discharge gate  12 B to be raised by actuator  13  allowing the discharge of the seven items from the tray and down chutes  14 A into the patient pack (not shown) which is positioned at its outlet. 
     The ability of the of the individual gates  9 B to open and close independently of one another enables the feeder  1  to accommodate for varying passage rates of items of product along individual channels  5 A. This reduces the possibility of more than one item of product collecting in the delivery compartment between the gates  9 B and  12  at one time. 
     Upon discharge of the items from the tray  5 , the discharge gate  12  is closed and the lips  9 B are again raised to allow the passage of seven further items into the delivery compartments between the gates  9 B,  12 . 
     So as to enable accommodation of both large and small items, the restraining bars  9  are detachable from the actuating rods so that they can be interchanged with bars  9 A having different lower surface profiles  9 A. Examples of two preferred profiles are illustrated in  FIGS. 5A and 5B .  FIG. 5A  illustrates a square bottomed bar  9  arranged to rest across the top of channel  5 A.  FIG. 5B  illustrates a wedged or V-shaped profile so as to more closely correspond to the profile of the channel  5 A. The first profile is thought to be more suitable for use with larger bevelled tablets  20  whereas the second profile is better suited to small items  21 . 
     In a variation, not shown in the drawings, the hopper  2  may also comprise a baffle which extends from a mid-point of the front wall diagonally downwards towards the lower edge of the hopper&#39;s back wall so as to form a funnel to restrict and/or control the flow of product onto the tray. This inhibits jamming of the product and/or multiple simultaneous passage of product items through an aperture  2 C. Further control of product in the vicinity of the funnel might be provided by a gating mechanism controlled by the control system, or by a sweeping mechanism as used in the second embodiment, to be described below. 
     The second embodiment of a filling machine is illustrated in  FIGS. 6 to 15 , and is broadly similar to the first embodiment, but incorporates a number of further variations, including neither of the gates being associated with a restraining bar but being formed separately and operating independently thereof. If there is no indication herein to the contrary, it may be taken that both embodiments incorporate similar features and operate similarly. 
     Referring initially to  FIGS. 6 to 10  in particular, there is shown a filling machine  21  comprising a repository for discrete items of pharmaceutical product, formed of a container  22  with an upper charging inlet  24 . The container  22  has an open bottom and a lower portion of its front wall is formed from a rubber strip member  26  secured by clamping screws  28 . The container  22  is slideably supported via a container mounting carriage  30  on slide rails  32  which are in turn supported on a hinged upper portion of a frame  34 . 
     A product feed tray  36  has a top surface  38  which defines seven parallel open-topped channels  40  running to a discharge end of the tray substantially along the length of the tray. In the channels  40  the surface of the tray has a V-shaped, including flat bottom V-shaped, cross section. The width and depth of each channel tapers gradually along its length from a nominal width and depth in a planar container base region of the top surface of the tray  36  to a maximum width and depth at point  42  where the planar portions of the surface terminate, as the tray slopes away, and is thereafter constant to an exit end of the tray from which product will, in use, be discharged. Throughout the channel&#39;s length, its width is greater than its depth so as to minimise jamming of items of product in the channel. The bottoms of the channels slope at a shallow angle of six degrees to the horizontal, downwardly towards the exit end. 
     The tray  36  is positioned such that the planar surface region is directly below the container  22  so as to form a base for the product repository. The tray  36  is also orientated such that the channels  40  extend under the front wall  26  of the container forming seven substantially triangular or trapezoidal apertures  44  (visible in  FIGS. 11A ,  11 B) defined between the channel surfaces and the bottom edge of the front wall  26 . The tray  36  is supported at each end on a rear mounting  46  and a front mounting  48 , comprising PTFE blocks, which allow limited movement of the tray from end to end, longitudinally of the channels, but substantially prevent vertical or lateral motion of the tray. The tray is agitated, in use, by an electromagnetic shaker  50 , of a kind known as a vibrating means in the blister pack filling art. The shaker  50  is itself mounted on frame  34 . 
     As can be seen in  FIGS. 11A and 11B , the container mounting carriage  30  enables the container  22  to be slid along slide rails  32 , horizontally across the top surface  38  of the tray  5 , in the direction in which the channels  40  extend. Movement of the container towards the discharge end of the tray causes the size of each aperture  44  to increase as a consequence of the enlarging width and depth of each channel. Conversely, movement away from the discharge end of the tray causes a reduction in the aperture size. Movement of this kind allows the apertures to be sized depending upon the product held within the repository, such as to allow only a single item of product to pass out of each aperture of the hopper at a time, according to the product item dimensions. 
     Also mounted on slide rails  32 , over the channels outside the container  22  in front of wall  26 , is a product delivery compartment inlet gate mechanism comprising seven pneumatic cylinders (not individually shown) on inlet gate cylinder mount  52 . Mounted in front of the container  22  is a restraining plate  54 , the under side of which is shaped with seven integral restraining bars  56 , one corresponding to each channel. The restraining bars  56  are positioned directly above the centreline of each channel and parallel to the sloping channel floor. The rear end of the plate  54  is tapered to closely abut container wall  26  above the apertures. At the front end of plate  54 , remote from the container  22 , are mounted seven delivery compartment inlet gates  60  comprising pivoted arms  62  tipped with triangular or trapezoidal gate pads  64 , shaped to fit the channel profile and close the channel when the gate is lowered into the channel, and to open the channel when the gate arm is raised. The gate pads are made of a pharmaceutically acceptable material that will not damage product items in the channels. Silicone rubber is one such preferred material. Each gate  60  may be raised or lowered independently of the other six gates  60 . 
     Because the restraining plate and inlet gates as well as the container are effectively mounted on the same carriage  30 , all can be moved across the tray  36  whilst maintaining a consistent mutual position relationship. But since the channel floors are consistently sloping from the interior of the container to the discharge end of the tray, provision for tray (and therefore also inlet gate) height adjustment is made in the form of restraining plate clamps  66 . 
     Each discharge compartment inlet gate arm  62  also incorporates an air pipe  68  whose inlet is seen in  FIG. 8 . Each pipe passes through the arm and emerges directed downwardly on the front of the arm, directed into the channel. These air pipes are arranged to deliver air jets into the delivery compartment when the compartment discharge gate  70  is opened to discharge product. The air jets assist the discharge of the product, and in keeping the channel free of product dust. Below the discharge end of tray  36  is a dust extractor duct  72 , connected to a vacuum duct  74  inside the frame  34  for collecting and removing such dust. 
     A further pair of slide rails  80 , parallel with the alignment of the channel floors, support a discharge gate carriage  82  on which is mounted a laser sensor (not shown) mounted on plates  76 , associated with each channel, as well as the single discharge gate  70  which is shaped to enter and close each channel at the same time, and a pneumatic operating cylinder (not shown) for the discharge gate. 
     The laser sensors are arranged to detect the presence of an item between the gates  60  and  70 . Each sensor has a complementary reflector which is formed from a polished base portion  78  of the V-shaped channel. The polished portion extends over the possible length and position of the product discharge compartment. The sensors and pneumatic actuators are controlled by a programmable logic control system also not shown. 
     Supported by the frame at the discharge end of the tray  36  is a vertical delivery box  84  containing seven individual chutes  86  whose inlets  88  are aligned with each of the channels  40 . A transparent cover plate  90  on the front of the delivery box allows the chutes to be inspected. The lower end of the delivery box is the discharge outlet of all seven chutes, and flexible ducts may be provided, as known in the art, to lead discharged products into their proper pockets in a patient blister pack  92  ( FIG. 15 ). 
     Inside the container  22 , adjacent the front wall  26 , is mounted a rotary sweeper  100 , driven by electric motor  102 . The sweeper has four stiff nylon blades  104  which continuously wipe the top planar surface of tray  36  inside the container above the outlet apertures  44 , sweeping away product from the planar surface so preventing build-up of product items at this point and facilitating a steady delivery of single product items along the channels through the apertures. 
     Before operation, a suitable restraining plate  54  is selected, with its restraining bars  56  adapted to the product item. We have found that six different plates  54  may permit the machine to be used with up to 120 different shapes and sizes of pharmaceutical product, no other change parts being required at all. Such plates may be of the general form shown in  FIGS. 12A and 12B , for tablets and caplets which have a flat or rounded face which causes the item to have a preferred way of lying against a flat surface (item  106 ,  FIG. 12A ), or of the form shown in  FIG. 14  (a similar form to that of restraining bar  9  shown in  FIG. 5B ) for items that are round or rounded such that they have no preferred face to lie on. Each of these two general forms may be made to accept and restrain a range of item sizes in the channels  40 . 
       FIG. 13  shows the restraining bars  56  of a plate  54  for tablets or caplets with preferred orientations. These bars are provided with entry guides  108  at the inlet ends, just outside apertures  44 . Guides  108  have twisted guide surfaces  110  which do not interact with items lying in the channels as shown in  FIG. 12A , but engage with, and turn into that orientation, items which are progressing along the channels resting against the opposite wall of the V. This ensures that all product items are aligned, and minimises jams. 
     Next, the carriage  30  is moved along slide rails  32  so as to tailor the aperture size  44  to the size of the product item. This may be done with lead screw  112 . The height of the restraining plate and inlet gates above the tray may also be adjusted. The position of the discharge gate is adjusted to form the correct size of delivery compartment. 
     In use, the machine operates substantially as previously described in relation to the first embodiment of the invention. 
     It will be readily apparent to the skilled person that numerous variations can be made without departing from the invention. For example, in possible alternative embodiments, the channels may not be tapered but rather decrease in width and/or depth in a graduated manner; the aperture size may be adjusted by movement of the surface relative to the repository; the aperture size may be adjusted by vertical movement as opposed to solely horizontal movement; any suitable sensors other than laser sensors can be used, for example infra-red sensors; and mechanical vibrators other than electromagnetic shakers can be used. 
     Further, the discharge gates need not be arranged to rest within the channel or profiled to suit but alternatively reside at the end of the channel. Additionally, means other than mechanical vibrators can be used to move the items through the aperture and along the channel. 
     While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof.