EP1417140A1

EP1417140A1 - Child resistant blister packs

Info

Publication number: EP1417140A1
Application number: EP02744941A
Authority: EP
Inventors: Thomas Toren
Original assignee: Toren Consulting Pty Ltd
Current assignee: Toren Consulting Pty Ltd
Priority date: 2001-07-25
Filing date: 2002-07-25
Publication date: 2004-05-12
Also published as: WO2003010065A1; AUPR655001A0; EP1417140A4; WO2003010065A8

Abstract

This invention concerns child resistant blister packs. Blister packs (1) typically comprise a clear plastics film (2) having a number of wells (3) or 'blisters' formed in it to receive small articles such as tablets. Aluminium foil (5) is heat sealed to the open face of the plastics sheet to close the tops of the wells (3) and seal the contents. The contents of a single well can later be released by pushing under the well so that the tablet pushes open the foil seal. The blister pack in this invention can be folded in half and locked in its folded configuration by means of an integrally formed locking device. The folded and locked blister pack has an integrally formed child-resistant opening device that requires the use of a tool such as a pencil or pen to unlock the pack and access its content.

Description

Title

Child Resistant Blister Packs

Technical Field This invention concerns blister packs. These packs typically comprise a clear plastics film having a number of wells or 'blisters' formed in it to receive small articles such as tablets. Aluminium foil is heat sealed to the open face of the plastics film to close the tops of the wells and seal the contents. The contents of a single well can later be released by pushing under the well so that the tablet pushes open the foil seal.

Background Art

Blister packs are used to package pharmaceutical products such as tablets and capsules, household products such as dishwasher detergent tablets, and others. The foil may bear printed instructions and may have colour coded regions to assist in correct dispensing of the contents. Further, the tablets are often brightly coloured and visible through the clear plastic, for the same reason. As a result the packs may be fascinating to small children, and since the tablets can have the appearance of candy, they may be tempted to release the tablets and eat them. Perritt Laboratories, who specialise in the testing of child resistant packaging in the USA, reported: "The tragic death of a three year old boy in the United Kingdom has triggered the British Standards Institute to fast-track a new British Standard for non-reclosable pharmaceutical packages. In February 2000 the three year old boy consumed 44 out of 56 ferrous sulphate pills, prescribed for his mother to combat anaemia, after opening two blister packs found on a kitchen countertop at his home,"

Disclosure Of The Invention

The invention is a folding blister pack comprising a single plastics film with a hinge running across it to form a firsjt panel extending on one side of the hinge, and a second panel extending on the other side of the hinge; where the: first panel has a key formed in the plastics film to extend above it, and the second panel has slot formed in the plastics film to extend below it, and the key and slot are positioned in the respective panels such that when the panels are folded together about the hinge, the key will enter and engage the slot; and where at least part of the key is formed with a ramping surface extending upward from the panel; and where half-cone shaped formations are formed in each panel such that when the panels are folded together about the hinge a split cone is formed with its apex adjacent the ramping surface where the ramping surface extends upward from the panel, and the split cone's open end is at the edge of the panel so that a cone shaped object may, in use, be inserted into it to force the key and slot apart.

The folded blister pack is held closed by the engagement of key in the slot, this engagement being the result of f rictional forces. The folded blister pack may be opened using a cone shaped object, such as a pencil, by inserting the sharp end into the split cone and advancing it so that it meets the ramping surface and forces the key out of the slot.

The axis of the split cone may extend in the plane between the panels and point in the direction of the projection of the ramping surface onto that plane. The ramping surface may be flat, and it may extend upwards, away from the plane between the panels, immediately from the apex of the split cone. The slot may also have a ramping surface to lie against the ramping surface of the key (when the pack is folded) and provide a greater degree of leveraging apart as the cone shaped object is pushed forward. The key and slot may be arranged so that the cone shaped object advances in a direction parallel to the hinge, or towards the hinge. When the direction of advance is parallel to the hinge, there may be a split cone at both ends of the key and slot pair.

There may be one or more key and slot pairs. Each pair may have a split cone, but this is not necessary. Where there is more than one pair, they may be arranged in parallel to each other, or they may be ganged so that behind a first pair there is a second pair. In this case the ramping surface of the key (and slot) of the second pair may extend in the same direction as that of the first pair, so that the cone shaped object will encounter both ramping surfaces in turn as it advances in the same direction from the apex of the split cone. Also in this case, the ramping surface of the second pair may extend from adjacent to or immediately after the first key and slot pair. The first key and slot pair may ramp down to meet the second pair. Alternatively, the ramping surfaces may extend in opposite directions, and in this case there may be a split cone associated with each. The locking device, namely the key and slot, and the opening device, namely the cone and ramping surface, of this invention, make the tablets in the blister pack less accessible to children. The split cone may be sized so that it is too small for a child's finger to enter it.

The hinge may be the same as that described in Australian patent No. 671979, USA patent No. 5,549,204 and European patent No. 0627906, all of which are by the same applicant and inventor as the present invention. This construction of hinge ensures that it is not too stiff, and that the two halves of the blister pack lie flat against each other when the pack is folded. When the pack is folded, only the tough plastic film is left exposed, in order to protect the aluminium foil from accidental puncturing, when a single blister pack is removed from its outer carton and kept in a handbag, pocket or drawer. With conventional, not folded blister cards, the aluminium foil is susceptible to being punctured through contact with hard and sharp objects in a handbag, pocket or drawer, causing the tablets to be exposed to contamination, oxidation and humidity.

To further enhance child-resistance, the product packed in the plastic blister pack can be heat sealed with a soft temper of, say, 20 μM thick ductile aluminium foil. Conventional pharmaceutical blister packs typically use aluminium having a hard temper which is therefore brittle.. This more ductile aluminium foil is less likely to puncture when touched from the aluminium side of the pack, thereby making the packaged product less accessible to children. The plastic film of the blister pack may be opaque, and possibly white, so as not to attract the attention of children to the pack and the product inside. This is contrary to conventional blister packs for tables, where the tablets are often coloured, inside transparent plastic film, thereby attracting the attention of children.

The main objective of this invention is to save children's lives. At the same time, blister packs with these locking and opening devices will be easier to access for elderly people, especially those with arthritic hands, than bottles with child resistant caps that have to be pressed down and turned at the same time.

Brief Description Of The Drawings

Some examples of this invention will now be described with reference to the following drawing : Figure 1 is a plan view of a first open blister pack.

Figure 2 is a side elevatioπal view of the blister pack of Figure 1. Figure 3 is a side elevatioπal view of the blister pack of Figure 1 when folded and locked,

Figure 4 is a part cross sectional view and part end elevational view of the blister pack in Figure 1.

Figure 5 is a part cross sectional view and part end elevational view of the blister pack in Figure 1.

Figure 6 is a part cross sectional view of the blister pack of Figure 3, and view of a pencil. Figure 7 is a plan view of a second open blister pack.

Figure 8 is a plan view of a third open blister pack. Figures 9, 10 and 11 are a series of cross sectional views of a pencil approaching a folded and locked blister pack, entering a first key and slot, and separating first and second keys and slots. Best Modes Of The Invention

Referring first to Figures 1 to 6, blister pack 1 comprises a plastics film 2 in which an array of wells 3 are thermoformed. The plastic film is opaque and white. The sheet 2 is hinged 4 allowing the pack to be folded, as described in Australian patent specification No. 671979, USA patent specification No. 5,549,204 and European patent specification No. 0627 906. Aluminium foil 5 (best shown in Figure 2) is heat sealed to the open faces of the wells 3 to close them.

The blister pack 1 incorporates a locking and opening device. The locking device includes an elongated key 10 thermoformed into the plastic film 2 and rising above the surface of the sheet. The key 10 is located parallel to the hinge 4 at one end of the blister pack 1. A matching slot 1 is thermoformed into the plastic film 2 and.recessed.below the surface of said sheet. Slot 11 being located symmetrically opposite the key 10 in relation to the hinge 4, at the other end of the blister pack 1 , so that when the flat blister pack 1 is folded along its hinge 4 over an angle of 180 degrees, the key 10 enters and engages the matching slot 1 . Frictional forces between the mating surfaces of key 10 and slot 11 keep the blister back 1 in a folded and locked state. The thermoformed key 10 and slot 11 include integrally formed ramping surfaces, in this case flat slopes, 12 and 13 at both ends. Also, half-conical shapes 14 and 15 are thermoformed in line with and at the end of said slopes 12 and 13 with their apexes adjacent to said slopes. When the blister pack 1 is folded and key 10 and slot 11 are engaged to lock, the half conical shapes 14 and 15 meet so as to form a complete but split cone 16, and slopes 12 and 13 lie against each other in line with the split cone (as best shown in Figure 6).

When a tool with a conical end, such as a pencil or ball-pen 27 is pushed into the split cone 16, its conical end wiil ride through the cone along slope 2 to wedge the blister pack open, overcoming the frictional force that kept the key and slot locked together. Once the, key and slot are unlocked, the blister pack can be unfolded and the contents of the wells, for instance tablets, can be dispensed by pushing them through the aluminium foil 5.

Figure 7 shows a second blister pack 30 with keys and slots at right angles to the hinge. Two thermoformed keys 31 and two matching thermoformed slots 32 are located on opposite sides and at right angles to the hinge 34. The keys and slot have ramps 35 and 36, and these are adjacent to half cones 37 and 38, as before. In this pack, the wells 39 are elongated.

Figure 8 shows a longer blister pack 40 with two thermoformed keys 41 and two matching thermoformed slots 42. The keys and slots have ramps 43 and 44, and these are adjacent to half cones 45 and 46, as before. The advantage for longer blister packs of having two shorter keys and slots instead of one long key and slot, is that these shorter keys and slots provide a firmer and more reliable interference fit when engaged, Experience with experimental blister packs has shown that when keys and slots are too long, the sidewalls of these keys and slots tend to bow and loose some of their grip. The blister pack 40 shown in Figure 8 has thermoformed pockets 47 for tablets on only one side 48 of hinge 49. These are heat sealed with aluminium foil over area 50. The blister pack's blank half 51 with no pockets, on the other side of hinge 49, serves as a cover when the blister pack is folded. This half 51 can be used for labels, printed or thermoformed embossed messages. Figures 9, 10 and 11 illustrate the progressive penetration of a pencil or pen 27 between the two halves of a folded blister pack with two keys and two slots parallel to the hinge, similar to blister pack 40 in Figure 8, and the separation of the locked keys 41 and slots 42. In Figures 9, 10 and 11 the split cone opening device 45/46 is provided on only one side of the blister pack, with additional ramps 52 and 53 added to the slots and keys respectively, in order to assist the forward movement of the pen or pencil 27 and the separation of the two halves of the blister pack.

The aluminium foil used to seal the packs is 20 μM thick. When the aluminium foil 5 is being heat sealed to the thermoformed plastic in blister pack 1 , it is fed between the key 10 and the slot 11 , in the direction parallel to the hinge 4. In blister pack 30 the aluminium foil is fed between the two keys 31 and the two slots 32, in the direction at right angles to the hinge. In blister pack 40 the aluminium foil is fed between the keys 41 and the slots 42, in the direction parallel to the hinge,

Although the invention has been described with reference to particular examples, it should be appreciated that it may be exemplified in many other forms and materials.

Claims

. A folding blister pack, comprising a single plastics film with a hinge running across it to form a first panel extending on one side of the hinge, and a second panel extending on the other side of the hinge; where the first panel has a key formed in the plastics film to extend above it, and the second panel has a slot formed in the plastics film to extend below it, and the key and slot are positioned in the respective panels such that when the panels are folded together about the hinge, the key will enter and engage the slot; and where at least part of the key is formed with a ramping surface extending upward from the panel; and where half-cone shaped formations are formed in each panel such that when the panels are folded together about the hinge a split cone is formed with its apex adjacent the ramping surface where the ramping surface extends upward from the panel, and the spit cone's open end is at the edge of the panel so that a cone shaped object may, in use, be inserted into it to force the key and slot apart.

2. A folding blister pack according to claim 1 , where the axis of the split cone extends in the plane between the panels and points in the direction of the projection of the ramping surface onto that plane. 3. A folding blister pack according to claim 1 or 2, where the ramping surface is flat.

4. A folding blister pack according to claim 1 , 2 or 3, where the ramping surface extends upwards, away from the plane between the panels, immediately from the apex of the split cone. 5. A folding blister pack according to any preceding claim, where the slot also has a ramping surface to lie against the ramping surface of the key. 6. A folding blister pack according to any preceding claim, where the key and slot pair are arranged so that the cone shaped object advances in a direction parallel to the hinge. 7. A folding blister paek according to- aim Sjiwhecsαhere is a split cone at both ends of the key and slot pair.

8. A folding blister pack according to any one of claims 1 to 5, where the key and slot pair are arranged so that the cone shaped object advances in a direction towards the hinge.

9. A folding blister pack according to any preceding claim, where there are more than one key and slot pairs,

10. A folding blister pack according to claim 9, where each pair has an associated split cone.

11. A folding blister pack according to claim 9 or 10, where the key and slot pairs are arranged parallel to each other. 2. A folding blister pack according to claim 9 or 10, where the key and slot pairs are ganged so that behind a first pair there is a second pair. 13. A folding blister pack according to claim 12, where the ramping surface of the key of the second pair extends in the same direction as that of the first pair. 4. A folding blister pack according to claim 13, where the ramping surface of the second pair extends from immediately after the first key and slot pair.

15. A folding blister pack according to claim 14, where the first key and slot pair ramp down to meet the second pair, 16. A folding blister pack according to claim 12, where the ramping surface of the key of the second pair extends in the opposite direction to that of the first pair.

17, A folding blister pack according to any preceding claim, where the split cone is sized so that it is too small for a child's finger to enter it. 18. A folding blister pack according to any preceding claim, where the hinge is the same as that described in Australian patent No. 671979, USA patent No. 5,549,204 and European patent No. 0627906.

19. A folding blister pack according to any preceding claim, where the plastic blister pack is heat sealed with a soft temper, ductile, aluminium foil substantially 20 μM thick.

20. A folding blister pack according to any preceding claim, where the plastic film of the blister pack is opaque.

21. A folding blister pack according to any preceding claim, where the plastics film is white.