Note: Descriptions are shown in the official language in which they were submitted.
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A HEAT SEALING MACHINE FOR A PACKAGING SYSTEM
This invention relates to a system for discretely packaging a plurality of
quantities of one
or more fluid or solid substances.
Particularly, although not exclusively, the system has been devised to meet
the needs of
patients and carers in the safe, accurate and convenient monitored dispensing
of
medication both in liquid and solid forms. Liquid medication, apart from the
use of
individual sachets or blisters, is currently supplied to the patient or carer
in large
containers from which individual doses are dispensed, usually into a measuring
spoon
from which the patient takes the medicine.
It is of the utmost importance that a patient should take an accurate dose of
the correct
medicine and that there should be no risk of confusion or of cross-
contamination
between patients should a large bottle of medication be used, perhaps
improperly, to
dispense the medication to different patients. Such a system is described and
claimed
in our co-pending patent application number GB 0719991.2 in which there is
provided a
container for discretely packaging a plurality of quantities of one or more
fluid or solid
substances, and comprising a tray having individual spaced compartments and a
plurality of vessels individually removably received within the respective
compartments
and adapted to contain the substances to be packaged, and a sealed film
releasably to
retain the vessels in the compartments prior to intended use, the film
sealingly retaining
the substances in the vessels prior to their intended use. The vessels are
individual pots
removably received within the compartmented tray, and the sealed film is
perforated
around the individual pots so that they may be removed from the tray
independently
when required. Thus, the film must be sealed around each pot to ensure that
the pots,
when removed, remain sealed until required for use.
The film may be printed with data representing the contents of the vessels,
their
intended dosage, and, for example, a patient's details.
The entire tray may be housed as one of several such trays, stacked one above
another,
in a cabinet or trolley for use, for example, in a nursing home, and it is
intended that the
tray should have an end face to which the film is also sealed to reveal data
pertaining to
the contents of the entire tray.
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While heat sealing of such a film to the tray along its upper and horizontal
plane in a
single operation is straightforward, nevertheless it is necessary,
substantially
simultaneously, to seal the end region of the film to the substantially
vertical end face of
the tray.
It is an object of the present invention to provide a heat sealing machine
which will
achieve the simultaneous sealing of the film to the upper and end faces of the
tray.
According to the present invention there is provided a heat sealing machine
for applying
heat at predetermined positions on a heat sealable film placed over a
compartmented
tray to seal the film to the tray on two planes, one substantially normal to
the other, the
machine comprising a heated plate adapted to bear upon a heat sealable film
superimposed on a first plane over a compartmented tray, a spring loaded
pressure
plate adapted to bear upon the heated plate, a supplementary heated member
movable
with respect to the heated plate and having a pressure member adapted to bear
against
the heat sealable film to become superimposed over the surface of the
compartmented
tray on a second plane.
The pressure plate and the supplementary heated member may becoming inter-
engaged when the pressure plate bears against the heated plate.
The heated plate may include shaped contact dies to cause the film to be
sealed to the
tray peripherally around each compartment of the tray.
The heated plate may include contact dies to cause the film to be sealed
between the
compartments of the tray.
The supplementary heated member may be pivotally mounted with respect to the
heated
plate and moved into a sealing position by the pressure plate when it bears
upon the
heated plate.
The supplementary heated member may be spring loaded thus to assume a non-
sealing
condition until engaged by the pressure plate.
The supplementary heated member may have adjustable heating pins which cause
the
film to be superimposed over an end face of the tray and spot-sealed thereto.
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Movement of the pressure plate may cause the film to be sealed around and
between
the compartments, and spot-sealed to the end face of the tray substantially
simultaneously.
Control means may be provided to enable the temperature of and/or the pressure
applied to the heated plate, and/or the duration of sealing contact to be
determined.
Means may be provided to introduce a tray and film into the machine and to
remove the
tray with the sealed film from the machine automatically.
An embodiment of the invention will now be described, by way of example only,
with
reference to the accompanying drawings in which:
Fig. 1 is an exploded perspective view of a container of a system for
discretely
packaging a plurality of quantities of one or more fluid or solid substances;
Fig. 2 is a schematic side elevation of a heat sealing machine made in
accordance
with the invention for use in connection with the container of Fig. 1;
Fig. 3 is a similar view of the heat sealing machine in a first phase of
operation;
Fig. 4 is a similar view of the heat sealing machine in a second phase of
operation;
Fig. 5 illustrates, on the container of Fig. 1, a sealing mode created by the
heat
sealing machine, and
Fig. 6 is a perspective view of a container clamping assembly.
Referring to Fig. 1, a container to be sealed comprises a tray generally
indicated at 10 of
a plastics material and formed to define side walls 11 and an array of
individual,
preformed, side-by-side compartments 12 each having a flexible base 13 and a
common
upper platform 14 extending across the tray 10 between the compartments 12. A
front
wall 15 provides a surface, as will be described, for the display of data
concerning the
contents of the tray.
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Located within each compartment 12 is a vessel in the form of an individual
pot 17 for
containment of a substance to be packaged. Each pot 17 has an upper flange 18
which
when the pot is located in the tray rests upon and flush with the platform 14.
The pots
may be of the same material as the tray.
The shape of the recess defined within each pot 17 is such as to have a curved
upper
rim 19 at least at one side. Opposite the curved rim 19 in each pot is a
straight edge 20.
The walls of each pot also conform to the shape of the upper rim.
For preference, each pot 17 is of such a size as to be an interference fit
within its
compartment, which is of complementary shape and size.
With all of the pots 17 in place a pharmacist may place the appropriate
medication in
each pot either by using a measured pipette for liquid medication or by
placing tablets or
capsules into the pots for solid medication.
To complete the container a flexible sheet 21 of a non-permeable heat sealable
material
having perforations 22 is placed over the filled tray and sealed toit, as will
be described.
The perforations 22 coincide with the outer peripheries of the pots 17 thus to
define
individual sealed films 23, one across each pot. The sheet 21 is sealed to the
platform
14 and around each individual pot flange 18, as will be described.
With the sheet in place the pots can be removed individually by pushing a pot
upwards
at the base 13 in the associated compartment thus breaking the perforation in
the sheet
21 while maintaining the integrity of the sealed film 23. Once the pot is
removed the
sealed film 23 remaining on the flange 18 can be peeled off when required to
open the
pot whereupon the medication can be taken. The curved rim 19 of each pot
facilitates
the taking of liquid medication. The regions of the flange 18 either side of
the curved rim
will have sufficient flexibility that they can be deformed to assist in
release of the
individual sealed film 23.
In this manner therefore individual pots can be removed whilst the remainder
are
retained and sealed on the tray 10. The individual films 23 may be printed,
for example,
with the time and date and the contents of the associated pot while a front
flap 29 of the
sheet 21 can be printed with information pertaining to the contents of the
entire tray.
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Referring now to Figs. 2 to 5, in order to effect a seal of the film 21 to the
tray 10 with its
pots 17 contained therein, the entire assembly of tray, pots and superimposed
film is
introduced into a heat sealing machine as shown schematically in Fig. 2. The
machine
comprises a heated plate 30 having on its lower face a plurality of dies 31
shaped to
5 determine the areas in which the film is sealed to the tray peripherally
around each pot
17 and between the pots, as will be shown.
The machine further comprises a pressure plate 32 which is spring loaded at 33
to bear
down on the heated plate 30, a pneumatic cylinder 34 or the like serving to
actuate the
pressure plate 32 when required.
Pivotally mounted at 35 on one end of the heating plate 30 is a supplementary
heated
member 36 having a row of adjustable sealing pins 37 mounted thereon. A spring
38
normally retains the supplementary heated member 36 in the position shown in
Fig. 2.
The supplementary heated member 36 and the pressure plate 32 have
complementary
inclined faces 39 and 40 respectively for a purpose to be described.
Fig. 2 shows the heat sealing machine in a non-operative position with a tray
10 and film
21 placed in readiness for sealing. The tray is slightly recessed to form a
well in which
the film 21 sits, and has upstands 53 (see Fig. 6) which engage complementary
registration notches in the edge of the film.
Referring now to Fig. 3, in a first phase of operation, pressure plate 32 and
springs 33
are shown bearing down on the heating plate 30 whose dies 31 are in sealing
contact
with the film 21 to seal it to the pots 17 and tray 10.
With reference to Fig. 5, it will be seen that the dies create a line of
sealing 41 around
the top of each pot 17 to seal the film 21 to the individual pots around their
flanges 18,
and simultaneously to spot-seal, at 42, to the tray between the compartments.
As can be seen from Fig. 2, when the heating plate 30 descends, the adjustable
sealing
pins 37 of supplementary heated member 36 cause the front flap 29 of the film
21 to be
folded over the front wall 15 of the tray 10.
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Referring now to Fig. 4, in the second phase of operation of the sealing
machine the
supplementary heated member 36 is moved pivotally by the wedge effect of the
coinciding faces 39 and 40 of the supplementary heated member 36 and the
pressure
plate 32 such that the adjustable heating pins 37 are forced against the front
flap 29 of
the film 21 to spot-seal it to the end face 15 of the tray 10. The sealing
positions of the
pins 37 are illustrated at 43 in Fig. 5.
Thus it can be seen that the film 21 is at least substantially simultaneously
sealed
against the upper horizontal face of the tray 10 and its vertical front wall
15.
Once the sealing action is completed the pressure plate 32 is retracted
together with the
heating plate 30 and the supplementary heated member 36 to resume their
positions as
illustrated in Fig. 2, whereupon the tray with its sealed film is
automatically discharged
from the machine. Introduction to and discharge from the machine of the tray
is carried
out automatically by an electrically, pneumatically or hydraulically operated
drawer
arrangement which delivers the trays smoothly into the sealing unit so as not
to disturb
any liquid contents of the pots 17, and clamps associated with the drawer
arrangement
ensure that the film 21 remains accurately in place over the tray. It is
important that the
film 21 shall not move out of register with the tray during its introduction
to the machine.
Preferably, the pressure plate 32 descends with a single motion thus to effect
substantially simultaneous sealing of the top and end of the film 21 thus to
minimise the
time taken for the tray to be sealed. The sealing process preferably requires
no more
than five seconds of heat application thus to minimise any adverse affect on
the
medication contained within the pots 17.
Referring now to Fig. 6, the drawer arrangement and clamps are illustrated
according to
one example. In the drawer arrangement the container 10 with its film 21
superimposed
thereon, is placed on a platen 44 which is transported into the sealing
machine and
which includes a pair of side clamps 45 each with a pair of spaced lips 46
which hold the
film 21 in place on the container 10. The clamps 45 are rotatable on shafts 47
journalled
in the platen 44. A pair of links 48 pivotally connected to the shafts 47 by
links 49 fixed
to the shafts 47 are also pivotally attached to a lever 50 having, in this
example, a handle
51. The lever 50 is pivotally connected to the platen 44 at 52 so that, in
Fig. 6, if the
handle and lever 50 are rotated in an anti-clockwise direction, this causes
the clamps 45
to release the container 10 after the film 21 has been sealed thereto.
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The lever 50 and handle 51 may be replaced by a rotatable knob on an axis at
52 in
order to reduce the height of the assembly. Indeed, any alternative mechanism
may be
provided to cause the clamps 45 to retain the film 21 and container 10 during
its
introduction into the sealing machine, and to release the sealed container
upon removal
from the machine. The mechanism including the drawer and clamps may be
operated
manually or automatically, but affords smooth movement in operation in order
to
minimise the risk of dislodgement or spillage of the contents of the pots.
Control means are provided to enable the temperature of and/or the pressure
applied to
the heated plate, and/or the duration of sealing contact to be predetermined
thus to
ensure sealing without unduly heating of the tray and its contents. Thus, the
user may
manage and control the combination of heat, pressure and time of application
of the
process so that the strength with which the film 21 is welded to the pots 17
can be varied
thus in turn to vary the ease with which the supplementary seals 23 may be
peeled from
the pots. The variable strength of weld also enables a level of child
protection to be
determined so that the supplementary seals may be peeled with sufficient ease
by the
patient but nevertheless represent a restriction to prevent a small child from
easily
removing the seal. The selection of weld strength is also of importance when
producing
sealed trays for elderly patients with chronic conditions such as arthritis,
where the
strength of the weld may be reduced accordingly.
The heat sealing machine made in accordance with the present invention
includes a
built-in compressor to provide compressed air to actuate the pneumatic
cylinder 34 in
order to move the pressure plate 32 to carry out the sealing operation.
The platen 44 on which the tray is placed and to provide a reaction for the
pressure of
the heating plate. To ensure complete uniformity of heat application the
platen may
include resilient means to ensure that the shaped dies of the heating plate
make uniform
pressurised contact with the film 21 throughout its upper surface. Thus, every
weld
created by the heating plate dies is of uniform strength.
It is not intended to limit the invention to the example described above, many
variations
being possible without departing from the scope of the invention as defined in
the
appended claims. For example, the individual adjustable pins 37 may be
replaced by a
single rail thus to cause a line-seal as opposed to spot-sealing of the front
flap 29 of the
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film 21. Similarly, pivotal movement of the supplementary heated member 36 may
be
effected other than by the wedge action of complementary faces 39 and 40.
Sealing of the film 21 is effected by virtue of the thermoplastic properties
of the film.
Alternatively, the film may be coated with a heat-sensitive adhesive thus to
be bonded to
the tray upon the application of heat.
