The present invention relates to a packaging unit of the kind defined
in the preamble of Claim 1.
It has become progressively more desirable in recent times to produce
packaging units from an homogenous material, in order to facilitate recovery of
the material. It is also desirable to be able to produce packaging units from thin
sheet-like materials, preferably transparent materials, with integrated unit closure
devices made of the same material as the unit in general, so as to enable the packaging
unit to be easily latched or secured when closed and also to be readily re-opened
and optionally resealed. This can be achieved with one known type of packaging
unit that includes an article supporting surface that has two mutually opposing
side-edges which are joined to a cupped lid or cover via respective fold lines.
The two fold lines are parallel when the two lids or covers are positioned over
the article supporting surface, and the article supporting surface and the lids
or covers form a substantially tight article enclosure.
It is also known in practice to achieve latching of a packaging unit
with the aid of a deep-drawn, convex stud on one packaging part, said stud being
pressed-fitted into a corresponding recess or cut-out in an adjacent packaging
part. Such a latching arrangement has a number of drawbacks, as is well known
to the skilled person. A more secure latching effect could, of course, be established
by providing the stud and the cut-out with undercuts, although such a solution
would place unacceptably high requirements on the packaging manufacturing equipment,
due to the requirement of special means for establishing undercuts and/or the packaging
material must be deformed when the packaging unit is removed from the production
FR-A-2203359 reveals a container, which is closed by a separate lid
device that consists of a sheet structure having two parallel separate folding
lines, which define an intermediate sheet portion with a large hole, and two end
portions, which mutually overlap when folded over the intermediate part. Undercut
closure means are arranged to hold the sheet portions in said mutual overlapping
condition. The large hole in the intermediate sheet portion is a necessity for
taking out objects from the container through the lid device.
The object of the present invention is to provide a more favourable
packaging-unit closure means of the aforedescribed kind without needing to form
undercuts in the manufacture of the packaging unit, or to form mould release means
on the packaging unit or in the mould used to produce the packaging unit, so as
to enable the packaging unit to be removed easily from the mould and so that the
packaging unit can be latched securely and easily, and optionally also re-opened,
while enabling the packaging unit as a whole to be produced advantageously from
one single type of material.
This object is achieved in accordance with the invention with a packaging
unit constructed in accordance with the following Claim 1.
The invention can be considered to be based realising the advantages
that can be achieved with a packaging unit of the aforedescribed kind when the
packaging-unit closure or latching means has the form described in more detail
in Claim 1, with the advantages accompanying said closure means as described hereinafter.
Further embodiments of the inventive packaging unit will be apparent
from the dependent Claims.
The invention has as its starting point a packaging unit that includes
an article supporting surface having two mutually opposing side-edges which are
joined to a cupped lid or cover via respective, generally parallel fold lines,
wherewith the two lids can be folded-in over one another and over the article
supporting surface so as to form an article enclosure. The two cupped lids include
end-walls at their opposing ends. According to the invention, that pair of end-walls
which lie in mutual abutment when the packaging unit is closed include a groove
and the adjacent second end-wall has a rib. When the two lids are swung-in over
one another on the article supporting surface so as to close the packaging unit,
the ribs will snap into corresponding grooves, by virtue of the end-walls "yielding"
Naturally, a rib and a groove coacting therewith may be provided
on each pair of end-walls of the packaging unit. Because the groove and the rib
extend from the edge of the lid, the rib and the groove can both be formed without
needing to provide undercuts or mould release means.
The inventive packaging unit is not limited to cupped lids nor yet
to article supporting surfaces of any particular configuration, although in the
illustrative embodiment the cupped lids may have cupped recesses that correspond
generally to half a straight cylinder and the article supporting surface may have
a correspondingly recessed shape in the form of a half straight cylinder, so that
when the packaging unit is closed the packaging space have the shape of a straight
cylinder. This space can be used conveniently to accommodate a row of chocolate
mints for instance. When the packaging material is transparent, a person receiving
the packaged mints is able to inspect the mints visually.
As indicated, the inventive packaging unit is produced by vacuum-forming
a softened plastic foil in a vacuum mould. Alternatively, the packaging unit can
be produced by pressing a plastic sheet between a matrix and a patrix. The packaging
unit may also be injection-moulded in a mould comprising a matrix mould-half and
a patrix mould-half.
The invention will now be described in more detail with reference
to an exemplifying embodiment thereof and also with reference to the accompanying
Fig. 1 is a perspective view of an inventive packaging unit.
Fig. 2 is an end view of the packaging unit shown in Fig. 1.
Figs. 3 and 4 illustrate two working steps in closing the packaging
unit shown in Fig. 2.
Fig. 5 is a schematic sectional view taken on the line V-V in Fig.
Fig. 6 illustrates another embodiment of an inventive packaging unit,
in a view corresponding to Fig. 2.
Fig. 7 is a side view of the article shown in Fig. 2.
The embodiment illustrated Figs. 1-5 is intended to tightly enclose
an article that has the shape of a straight cylinder, more specifically a stack
of mints. The packaging unit is comprised of a thin, sheet-like preferably transparent,
plastic material which has been shaped into three main parts 1, 2, 3, each having
the form of a trough intended to accommodate a respective half of the packaged
article . The packaging unit parts 1 and 3 therewith are of mutually the same
size in principle, whereas the packaging unit part 2 is slightly larger than the
part 3 so as to be able to also accommodate the material thickness of the part
Each of the parts 1, 2 3 is comprised of a respective mantle surface
15, 25 and 35, and two end-walls 11, 21 and 31 respectively. The part 2 has a flange
8 on its free long edge. The long edges of the packaging-unit parts 2 and 3 are
connected to the long edges of the packaging unit part 1 via respective fold line
formations 4 and 5.
The edges of the trough-shaped or cupped parts 1, 2, 3 can be considered
to be in the state shown in Fig. 1, said flange 8 also protruding out in this plane.
It can be imagined that the sheet-like packaging unit shown in Fig.
1 is formed from a flat, pre-heated sheet of plastic, by being vacuum-drawn down
into a mould that has the configuration illustrated in Fig. 1.
Returning now to Fig. 1, it will be seen that the end-walls 31 include
a straight groove 32 which extends from the free edge of the end-wall (the plane
P) generally perpendicularly to said edge. The groove 32, which can be considered
to be deep-drawn in the end-wall 31, bulges inwardly of the interior of the trough-shaped
The part 2 has a rib 22 which is complementary to the groove 32 and
which is formed so that when closing the packaging unit the rib can be received
in the groove 32.
The end-walls 21, 31 (and 11) are parallel and lie generally in a
common plane (the end-wall 21 lies in a plane that borders on the plane 31). The
plane of the end-walls 21, 31 defines an angle with a normal plane to the axes
of the fold lines 4, 5, so that the end-walls can be released readily from the
mould (see Fig. 7). The groove 32 and the rib 22 are directed so that the rib 22
will engage in the groove 32 when the part 2 is in close surface contact with the
outside of the part 3.
As will be seen from Fig. 3, the part 3 is first folded back around
the fold line 5 and in over the part 1, which can be said to form an article supporting
surface. The part 2 is then folded in over the part 3 around the fold line such
that the end-wall 21 will lie on the outside of the end-wall 31. The rib 22 will
slide on the outer surface of the end-wall 31, wherewith the end-wall 31 flexes
resiliently inwards while the end-wall 21 flexes resiliently outwards. When the
part 2 finally makes full contact with the part 3, the rib 22 will snap into the
groove 32 and therewith latch the packaging unit. The flange 8 forms a thumb grip
which enables the packaging unit to be opened up, in the reverse order.
It will be evident from the aforegoing that the formations 22, 32
will preferably be made parallel as the packaging unit is formed, so as not constitute
an obstruction to the release of the packaging unit from the mould, or to make
such release impossible. Neither shall the packaging unit in general have any
surfaces that will make release of the packaging unit from the mould difficult
or impossible to achieve.
In the embodiment illustrated in Figs. 1-5, the formations 22, 32
are directed perpendicularly to the free end-wall edges 23, 33 (which lie in the
plane P), although it will be understood that the groove 32 and the rib 22 need
not be perpendicular to the edges 23, 33 and need not extend up to the opposite
edge of the end-wall 21, 31. Neither need the formations 22, 32 lie in the centre
of respective end-walls.
Fig. 6 illustrates an embodiment in which the part 1 has the form
of a generally flat article supporting surface and the packaging unit parts 2 and
3 have the form of a trough which includes flat bottoms and sloping side-walls.
The end-walls are shown to lie at a small angle to a normal plane to the axes
of the fold lines 4, 5, so as to enable the end-walls to be released easily from
the mould. However, the end-walls may slope at a much greater angle than that shown,
for instance an angle of 45° to the normal plane. It will be seen that the formations
22, 32 are parallel but not perpendicular to the plane P. It will also be seen
that the formations 22, 32 do not lie at the broad centre region of the end-walls
21, 31. Neither do the formations 22, 32 extend to the bottom of the packaging-unit
parts 2, 3.
In the embodiment illustrated in Figs. 1-5, the flange 8 forms a
thumb grip which facilitates opening of the packaging unit. It will also be understood,
however, that the flange 8 may form an extension flap by means of which the packaging
unit can be hung more easily on a display rack, said flange 8 suitably having
appropriate perforations for this purpose. It will also be understood that when
the flange is to be used to hang the packaging unit, it need not be provided on
the free long edge of the outer packaging part 2 but may be an adjoinment to one
of the end-wall edges 13 instead.
Although the embodiment shown in Fig. 1 has latching formations 22,
32 on each of the opposing ends of the packaging unit, it will be understood that
it is sufficient to provide the formations 22, 32 solely at the ends of the packaging
The force with which the groove 32 and the rib 22 coact may be adapted
by suitable choice of their respective cross-sectional profiles. For instance,
if the groove and the rib are formed with straight angles (c.f. Fig. 5), it will
be difficult to reopen the packaging unit. On the other hand, if the formations
22, 32 are given a semi-cylindrical cross-sectional shape with rounded transitions
to the end-walls 21, 31, it will be much easier to reopen the packaging unit. The
ease with which the packaging unit can be closed and opened will increase with
an increasing slope of the end-walls to the normal plane of the fold line direction.
It will be obvious to the skilled person that the packaging unit
itself, with the exclusion of the unit closure members shall be configured so as
to enable the unit to be manufactured without movable mould parts and without
component shapes that render release of the packaging unit from the mould difficult
to achieve. The unit closure members are also shaped to fulfil these requirements,
said unit closure members sliding into mutual alignment as the cupped parts of
the packaging unit are swung to a closed state, and wherewith the resilience of
the end-walls provides the spring effect necessary for the rib to snap into (and
out of) engagement with the groove.
The invention provides a good unit latching function, despite the
relatively low tolerance requirement on the formations 22, 32.