BLISTER WITH TILTING SIDE-WALLS

EMBALLAGE-COQUE AVEC PAROIS LATERALES A INCLINAISON

English Abstract

A blister sheet (1) has a generally rectangular blister (2) formed with one
pair of longer side walls (7) having parallel
steps (8) and a second pair of shorter side wall (9) devoid of steps. The side
walls serve to space a front face (5) of the blister
from the plane of a rupturable foil backing sheet (4) which retains medication
doses (nor shown) inside the blister until they are to
be taken. The medication doses are ejected from the cavity of the blister (2)
by depressing its front face with finger pressure so
that they are forced against the backing sheet (4) with sufficient force to
rupture it. During the application of finger pressure to the
front face (5) it bows downwardly in its central region as indicated by the
broken outline. Simultaneously the end walls (9) tilt in-
wardly towards one another so that any medication doses lying against them are
forced into the central region of the blister from
which they can be ejected more easily by the descending front face (5).

French Abstract

L'invention porte sur une feuille d'emballage-coque (1), qui a un emballage-coque globalement rectangulaire (2) formé avec une paire de parois latérales plus longues (7) ayant des échelons parallèles (8) et une seconde paire de parois latérales plus courtes (9) sans échelons. Les parois latérales servent à espacer une face avant (5) de l'emballage-coque vis-à-vis du plan d'une feuille de support à feuille apte à être rompue (4) qui maintient des doses de médicament (non représenté) à l'intérieur de l'emballage-coque jusqu'à ce qu'elles doivent être prises. Les doses de médicament sont éjectées à partir de la cavité de l'emballage-coque (2) par enfoncement de sa face avant avec une pression des doigts, de telle sorte qu'elles sont forcées contre la feuille de support (4) avec une force suffisante pour rompre celle-ci. Durant l'application d'une pression des doigts sur la face avant (5), celle-ci s'infléchit vers le bas dans sa région centrale, comme indiqué en pointillés. Simultanément, les parois d'extrémité (9) s'inclinent vers l'intérieur, l'une vers l'autre, de telle sorte que toutes doses de médicament se trouvant contre celles-ci sont forcées dans la région centrale de l'emballage-coque, à partir duquel elles peuvent être éjectées plus facilement par la face avant descendante (5).

Claims

6

The embodiments of the invention in which an exclusive property or privilege
is
claimed are defined as follows:
1. A blister sheet having a planar back and provided with a blister having
first and
second pairs of side walls and a front face held spaced from the plane of the
back of the
sheet by the side walls, the blister being of elongated shape and the first
pair of side walls
being longer than the second pair of side walls, the first pair of side walls
being so
formed that they yield under finger pressure applied to the front face of the
blister while
progressively collapsing from the front face in response to increasing finger
pressure
being applied to the front face, and the second pair of side walls responding
to the finger
pressure by tilting towards one another so that any medication dose which may
be located
against a tilting side wall is displaced towards a position lying beneath the
front face and
from which it can be ejected by increasing finger pressure, and wherein the
first pair of
side walls are formed with parallel steps, and the second pair of side walls
have their
central regions devoid of steps or corrugations and of planar trapezoidal
shape so that
they can tilt towards one another about their edges where they join the
portions of the
blister sheet from which the associated blister protrudes.

Description

CA 02763224 2011-11-23
WO 2010/135765
PCT/AU2010/000623
1
BLISTER WITH TILTING SIDE-WALLS
Field of the invention
THIS INVENTION relates to a blister of a blister sheet and is more
specifically
concerned with an improvement in, or a modification of the invention described
and
claimed in our Australian Patent No. 779458 (hereinafter referred to as "the
parent
patent") and to which the present application is for a patent-of-addition.
State of the art
The parent patent describes and claims an invention comprising a blister sheet
formed
with a blister having side walls and a front face which is held spaced from
the plane of
the back of the blister sheet by the side walls which are designed to yield
gently while
progressively collapsing from the front face in response to increasing finger
pressure
being applied to the front face. This enables older people to more easily
depress the front
face of a blister with sufficient force to eject medication doses from the
cavity of the
blister. This force must be sufficient to rupture a backing sheet sealing the
cavity of the
blister and also to buckle the side walls of the blister sufficiently to
enable the front face
of the blister to be pressed down as far as the backing sheet.
Medication doses within the blister may have many different sizes and shapes.
Some of
these shapes are such that it is possible for an occasional medication dose to
be
inadvertently trapped between a collapsing side wall of the blister and its
front face
while the latter is being pushed by finger pressure towards the backing sheet.
An elderly
patient may not notice that this has occurred and thus fail to take the total
number of
medication doses which a doctor has prescribed.

CA 02763224 2014-10-24
2
Object of the invention
An object of this invention is to provide an improved shape of blister.
Summary of the invention
The present invention provides a blister sheet formed with a blister having
two pairs of side
walls and a front face which is held spaced from the plane of the back of the
sheet by the
side walls, one pair of opposed sidewalls being so formed that they yield
gently while
progressively collapsing from the front face in response to increasing finger
pressure being
applied to the front face, and the other pair of sidewalls responding to the
finger pressure
by tilting towards one another so that any medication dose which might be
located against
a tilting side wall is displaced towards a position lying beneath the front
face and from
which it can be ejected by increasing pressure. This enables a blister to have
its contained
medication doses ejected through the backing sheet with more certainty than is
the case
with a blister having all of its side walls corrugated.
Preferably the blister is of elongated shape and the first pair of sidewalls
are rather longer
than the second pair of side walls. The first pair of sidewalls are suitable
formed with
parallel steps, for example three such steps. The side walls of the second
pair are suitably
devoid of steps and are smooth so that their stiffness is not impaired and
they can tilt
gradually towards one another as finger pressure is applied to the front face.
According to an aspect of the present invention there is provided a blister
sheet having a
planar back and provided with a blister having first and second pairs of side
walls and a
front face held spaced from the plane of the back of the sheet by the side
walls, the blister
being of elongated shape and the first pair of side walls being longer than
the second pair
of side walls, the first pair of side walls being so formed that they yield
under finger
pressure applied to the front face of the blister while progressively
collapsing from the front
face in response to increasing finger pressure being applied to the front
face, and the second
pair of side walls responding to the finger pressure by tilting towards one
another so that
any medication dose which may be located against a tilting side wall is
displaced towards
a position lying beneath the front face and from which it can be ejected by
increasing finger
pressure, and wherein the first pair of side walls are formed with parallel
steps, and the
second pair of side walls have their central regions devoid of steps or
corrugations and of
planar trapezoidal shape so that they can tilt towards one another about their
edges where
they join the portions of the blister sheet from which the associated blister
protrudes.

CA 02763224 2014-10-24
2a
Introduction to the drawings
The invention will now be described in more detail, by way of example, with
reference to
accompanying drawings, in which:-
In the drawings
FIGURE 1 is a plan view of a blister forming part of a blister sheet;
FIGURE 2 is a diagrammatic vertical section through the blister of figure 1
taken on the
line and in the direction indicated by the arrows 11-11 in figure 1;

CA 02763224 2011-11-23
WO 2010/135765
PCT/AU2010/000623
3
FIGURE 3 is an end view of the blister of figure 1 taken on the line and in
the direction
indicated by the arrows 111-111; and,
FIGURE 4 is a view similar to figure 2 and shows a stage in the collapsing of
a blister by
finger pressure applied to its front face, the end walls of the blister and
its front face
being shown in full outline in its initial position, and in broken outline in
an intermediate
position it assumes during ejection of medication doses from the cavity of the
blister.
Description of preferred embodiment
In order to avoid burdening the present specification with unnecessary detail
concerning
the way in which the blister sheet is used in conjunction with a foil backing
sheet and a
stiff folder, reference should be made to the specification of the parent
patent for such
detail and the reader is to understand that the blister sheet of the present
invention is used
in a similar manner.
Referring to figures 1,2 and 3 these show part of a transparent, vacuum-formed
plastics
blister sheet 1 having a blister 2 of generally truncated pyramidal shape and
which
protrudes from one side of the blister sheet 1. The blister tapers in the
direction of its
protrusion. A finger-rupturable, airtight backing sheet 4 , which may be a
thin metal foil,
is adhesively sealed to the back of the sheet 1 around the marginal edge of
the blister 2
and acts to seal prescribed medication doses (not shown) within the cavity of
the blister.
The blister has a generally oblong and outwardly convex front face 5 with
generously
rounded corners 6 and is held spaced from the plane of the backing sheet 4 of
the blister 2
by four side walls arranged in two pairs respectively referenced 7 and 9. The
longer pair
of side walls 7 are provided with parallel steps 8 which extend around the
corners 6 and
are parallel to the plane of the backing sheet 4. The shorter pair of parallel
side walls 9
have flat central regions of generally trapezoidal shape as shown in figure 1
and which
taper upwardly towards the front face 5 of the blister as clearly shown in
figure 2.

CA 02763224 2011-11-23
WO 2010/135765
PCT/AU2010/000623
4
Pairs of narrow, parallel, bleed openings are integrally formed in the blister
sheet 1
provide narrow ducts 10 extending between the central portions of the
neighboring
shorter side walls 9 of respective blisters. These ducts have an internal
cross-section of
about one square millimeter and are about four millimeters long. They are
integrally
moulded with the blister sheet 1. The ends of the ducts 10 open into the
cavities of
respective blisters 1 so that air can escape from each blister, when its front
face is
depressed towards the backing sheet 4 by finger pressure, by way of the ducts
10 into the
cavities of the neighboring blister or blisters I. If either or both of the
blisters to which
the ducts 10 are connected, are connected to atmosphere as a result of their
contents
having already been ejected, the air passing through the ducts 10 discharges
to
atmosphere to relieve the pressure inside the blister being opened. On the
other hand, if
the neighboring blister at the other end of the ducts 10 is still intact, its
shape allows it to
dilate slightly to absorb the air passing through the ducts 10. Thus, in each
case, the air-
pressure inside the blister which is in the course of being opened, is not
significantly
increased and this makes opening of the blister easier as less finger pressure
is required to
depress its front face than would otherwise be required were the ducts 10 not
present.
Operation of the preferred embodiment
In order to eject the medication doses contained in a particular blister
cavity and which
may be in the form of tablets or capsules, the patient depresses the front
face 5 of the
selected blister by applying finger pressure to it. The pressure is
transmitted by way of
the medication doses to the backing sheet 4 of the blister, causing it to
rupture. The
downward pressure on the front face 5 also causes air within the blister to
flow through
the ducts 10 at one or both ends of the blister cavity so that the depression
of the front
face causes negligible build-up of air pressure inside the blister being
opened and which
might otherwise prevent the medication doses from being forced against the
backing
sheet with sufficient force to rupture it.
The steps 8 in the longer side walls 7 of the blister allows the blister to
collapse
progressively from the front face 5 when downward pressure is applied to it.
The steps 8

CA 02763224 2011-11-23
WO 2010/135765
PCT/AU2010/000623
also allows neighboring blisters interconnected by the ducts 10 to expand
slightly, if they
have not been previously opened, so that air flowing through the ducts 10 can
escape.
Turning next to figure 4 it will be noticed that the absence of steps 8 in the
flat
trapezoidal regions of the shorter side walls 9 at the ends of the blister
results in them
being more resistant to collapsing that the longer side walls 7. As a
consequence, the
finger pressure applied to the central portion of the front face 5 causes it
to bow
downwardly in the middle, as indicated in broken outline parts in figure 4.
This bowing
causes the end walls 9 to tilt towards one another about their attachments to
the coplanar
parts of the blister sheet 1 which are adhesively attached to the backing
sheet 4. This
tilting causes any medication doses adjacent the tilting side walls 9 to be
pushed towards
the central portion of the blister cavity where rupturing of the foil,
diagrammatically
illustrated at 12, is most likely to occur. There is thus less risk of a
medication dose being
inadvertently retained in the opened blister by being trapped between the edge
of the
front face 5 and the shorter side walls of the blister.

Representative Drawing