US 20040069675 A1
A blister package comprises a medication holder molded from a transparent plastic sheet and having one end closed by an integrally-formed flexible and non-resilient wall and the other end closed by a removable lid attached to the holder by a line hinge. The holder has four ribs pressed out of its sidewall and which respectively receive four detents provided at the sides of a central spigot formed on the lid and which locate in the interiors of respective ribs. The sidewall of the holder provides a socket for the reception of the lid spigot and the combined wall strengths of the spigot and socket when interfitting with one another makes the combination relatively inflexible until the lid is removed from the holder.
1. A blister package for mounting in an aperture of a carrier sheet comprises:
a holder made from plastics material and having a loading aperture surrounded by a resiliently flexible wall portion providing a socket;
a lid for closing the aperture and formed with a resiliently flexible spigot which fits snugly into the socket to close it securely;
cooperating fixtures on the spigot and socket which retain the lid closed until the package is to be opened;
means for facilitating the removal of the lid from the holder when its contents are to be accessed; and
spaced elements projecting outwardly from the blister package in the vicinity of the spigot and socket, at least one of the elements being spaced from the holder opening.
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 This application claims benefit of U.S. Provisional Application No. 60/417,240 filed Oct. 8, 2002.
 This invention relates to blister packaging and is more specifically concerned with designing a blister and its associated lid in a manner which enables the closed blister to be retained securely in position in an opening in a carrier sheet. The combination of blister and lid are referred to hereinafter as a “blister package” or “blister packaging.”
 Items such as pharmaceutical medication in the form of tablets and capsules prescribed by a doctor, are commonly dispensed by pharmacists to patients in the form of blisters pre-loaded with medication the patient is required to take at a particular time on a particular day. These blisters are commonly mounted on a carrier sheet marked with the times of day and the days of the week when the medication is to be taken.
 Blister packaging mounted on a carrier sheet as described above is easy and convenient to use when the patient is educated and understands the need to comply with a doctor's advice. However there are sections of the community which, because of their remoteness, may be poorly educated or live a nomadic life style. This results in conventionally designed blister packaging being easily damaged or mislaid, and often the compliance markings on them cannot be understood. The cost of replacing such packaging can be considerable, quite apart form the cost of replacing the medication, and this increases the difficulties associated with servicing the health needs of isolated outback communities. Any innovation which can reduce these problems areas is welcome.
 An object of this invention is to provide an improved blister package.
 In accordance with the present invention a blister package for mounting in an opening of a carrier sheet comprises a holder made from plastics material and having a loading aperture surrounded by a resiliently flexible wall portion providing a socket; a lid for closing the aperture and formed with a resiliently flexible spigot which fits snugly into the socket to close it securely; co-operating fixtures on the spigot and socket which retain the lid closed until the package is to be opened; means for facilitating the removal of the lid from the holder when its contents are to be accessed; and, spaced elements projecting outwardly from the blister package in the vicinity of the spigot and socket, at least one of the elements being spaced from the holder opening.
 A blister package as described above can be mounted in an opening in a carrier sheet by trapping the sheet between the elements on the package. The holder of the package may be inserted into its opening first and then, after loading the holder with the required contents by way of its aperture, the lid may be fitted. The spigot of the lid then lines the wall of the holder to increase the resistance of the holder wall to inward yielding in the region of the elements. This reduces the risk of the closed package being inadvertently dislodged from its opening in the carrier sheet.
 In the preferred arrangement of the invention, the wall of the holder is provided around the loading aperture with a flange element which prevents movement of the holder through the carrier opening in one direction. Movement of the holder in the other direction is conveniently resisted by an external rib element on the wall and which is spaced from, but extends parallel to the flange. The rib may be flute-shaped to provide a trough in which may locate a detent formed on the spigot of the lid. The detent acts to reinforce the strength of the rib against inward buckling. The lid may also be made of a suitably resilient material. With this arrangement, the holder is inserted into its opening in the carrier sheet before the lid is applied. During this insertion movement, the flexibility of the holder wall allows it to yield resiliently so that the rib can be pushed through the opening without damage to it or the edge of the opening. The limit to which the holder can be moved through the opening is determined by an element, such as the external flange or a second element, arranged around or close to the aperture of the holder. After loading the holder, the lid is applied. As the spigot on the lid enters the socket of the holder, the flexible resilience of the spigot allows it to yield resiliently until the detent enters the trough. This serves to hold the lid in position until manually released. The aggregated wall thicknesses of the spigot and the socket wall surrounding it, enhance the stiffness of the combination to resist inward flexing, so that the carrier sheet is firmly held between the two elements on the closed blister package. The detent also reinforces the strength of the rib.
 Suitably the lid and holder are made by a vacuum-forming process from a single strip of plastics material, and a line hinge is formed between them so that the lid and holder remain connected when the lid is opened.
 Conveniently the central portion of the holder is thinner than its wall surrounding the loading aperture, the extent of the thinning of the central portion being such that it loses its resilience entirely and becomes very flexible indeed. This allows the contents of the blister to be easily pushed out of the holder by finger pressure, if necessary.
 An advantage of the blister package of the invention is that it may be cheaply made and can be re-used a number of times without damage.
 The invention will now be described in more detail, by way of example, with reference to the accompanying largely diagrammatic formal drawings, in which:
FIG. 1 is an under-plan view of a carrier sheet containing two lines of openings one line of which has blister packages mounted in the openings,
FIG. 2 is a side view of the sheet of FIG. 1,
FIG. 3 is a side view of two blister packages in their open condition and removed from the carrier sheet, the positions of lids of the package when in their closed positions being shown in phantom outline, and
 FIGS. 4-7 are sections through FIG. 3 taken on the lines and in the directions of the arrows IV-IV, V-V, VI-VI and VII-VII respectively.
FIGS. 1 and 2 show a stiff sheet of cardboard 1 about 1 mm thick and providing a carrier having openings 3 for fourteen blister packages 2 of which seven are illustrated. The packages 2 are held in respective generally rectangular openings 3 arranged in two lines of seven openings.
 The blister packages 2 are vacuum-formed from a transparent strip 4 of thermo-plastics material which provides all seven packages. Each package 2 comprises a holder 5 connected by hinge line 6 to a lid 7 as shown in FIG. 3. The material of the strip 4 is such that it is stiffly resiliently flexible but when its thickness is reduced in the region of the central portion (referenced 13) of the holder by the vacuum-forming process, the material of the strip loses its resilience and acquires great flexibility. Typically the strip is made from polyvinylchloride (PVC) and is 0.3 mm thick before it is vacuum-formed.
 As shown in FIGS. 3, 4 and 7, the holder 5 is rectangular with rounded corners when viewed in cross-section, and is sufficiently deep to hold a number of medications which are to be taken by a patient at a particular time on a particular day. These times and days are signified by indicia (not shown) marked on the carrier sheet 1 alongside the blister packages. The underside of the holder provides a generally rectangular medication loading aperture 12 when the holder is inverted, and which may be closed by the insertion into it of a spigot 10 provided on the lid 7. The lid is also provided with a tab portion 20 which can be gripped between the fingers to pull the spigot 10 from the socket of the holder 5 when the package is to be opened.
 As may be seen from FIGS. 3, 4 and 6, the portion of the holder 5 surrounding the aperture 12 provides a wall 14 which is still resiliently flexible, as its thickness has not been reduced to the same extent as the central portion 13. An element in the form of a plinth-like flange 15 surrounds the wall 14 around the aperture 12 and is formed during the blow-molding process. The flange limits movement of the holder 5 in one direction through the opening 3 of the carrier sheet 1.
 The wall 14 is provided with four outwardly projecting ribs 16 extending parallel to, but spaced from the flange 15. One rib 16 is formed on each side of the holder, respectively, and the ribs provide elements for limiting movement of the holder 5 in the reverse direction through the opening 3. The spacing between the ribs 16 and the flange 15 is slightly larger than the thickness of the carrier sheet 1 so that the holder 5 can be inserted into any one of the openings 3 until the ribs 16 encounter the marginal edge of the sheet 1 surrounding the opening 3. By exerting a little more pressure on the holder, the wall 14 yields resiliently to allow the ribs 16 to pass through the openings 3. The holder 5 is now trapped in the opening 3 by contact of its ribs 16 with one face of the sheet 1 and the contact of its flange 15 with the opposite face of sheet 1.
 The central spigot 10 provided on the lid 7 is shaped to fit snugly into the socket provided by the interior surface of the wall 14 of the holder 5. The spigot 10 is provided externally at its leading end with four elongated detents 17 shaped to fit in respective troughs provided by the interiors of the ribs 16 of the holder 5. This is shown in phantom outline in FIG. 3. Each lid 7 is separated from its neighbor by a cut in the strip 4, as shown at 18, so that the packages can be opened and closed independently. The hinge 6, provided by a reduced thickness line in the plastics material of the strip 4, ensures that the lid 7 and holder 5 of each package remain together when the package is opened as shown in FIG. 3.
 The tab 20 formed along the edge-portion of the lid 7 remote from the hinge 6 can be gripped between the fingers to facilitate the progressive release of the lid from the holder 5 when its contents are to be accessed.
 Operation of Preferred Embodiment
 It will be noted from the phantom outline in FIG. 3 that when the package is closed, the spigot 10 fits snugly against the inside wall 14 and its detents 17 fit into the interiors of the ribs 16. As apparent from FIGS. 5 and 6, the shape of the spigot 10 is such that it is fairly resistant to inward flexing. However this resistance is not sufficient to prevent the entry of the spigot 10 of the lid 7 into the socket provided by the wall 14 of the holder. The resistance to inward flexing of the spigot 10 acts to reinforce the natural resistance to inward flexing of the wall 14 of the holder 5 so that the aggregation of the two resistances is sufficient to prevent inadvertent withdrawal of the closed package from its opening 3 in the carrier sheet 1.
 The above described arrangement of package is relatively cheap and easy to manufacture, assemble and use, and the spigot and socket arrangement of the lid and holder coupled with the avoidance of holes in the holder, greatly reduces risk of the contents of the closed holder being contaminated by dust and other pollutants. The package can be used many times without adverse effects, and can be made compactly by arranging the lines of openings 3 in staggered formation and by providing fold lines on the carrier sheet. These enable the packages to interfit with one another when the sheet is folded to bring the assembly into its transport condition. The packages then protect one another from damage and the folded sheet can be transported inside a matchbox-like surrounding sleeve.
 In an unillustrated modification of the arrangement just described, the stiff cardboard sheet providing the carrier and referenced 1 in FIGS. 1 and 2 is replaced by two superimposed thinner sheets each of which has a line of apertures for containing the holders 5. The two thinner sheets are formed by folding opposite halves of a thin cardboard sheet back on itself to provide a carrier of the requisite stiffness. When so folded back on itself, the two lines of apertures are brought into registration with one another. The unfolded flexible cardboard sheet is suitably provided with a crease line to assist correct folding. By making the carrier from a larger flexible sheet folded back on itself, the sheet can be printed using commercial printing equipment more easily when in a single thickness flexible condition than is possible when using a single thickness of a stiffer sheet.