Package with a closing device

A packaging unit includes an article supporting surface (1) which is joined to a cupped lid (2, 3) on two mutually opposing side-edges via respective, generally parallel fold lines (4, 5). The article supporting surface (1) and the lids (2, 3) together form an article enclosure. A unit closure means (22, 32) is provided for holding the packaging unit in a closed state. The two lids (2, 3) have end-walls (21, 31) and the end-walls at at least one end of the packaging unit lie adjacent one another and essentially in contact with each other when the packaging unit is closed. The unit closure means includes a groove (32) in one end-wall (31) of one lid (3), and a rib (22) in that end-wall (21) of the other lid (2) that lies adjacent the groove-containing end-wall when the packaging unit is closed, such that the rib (22) engages the groove (32) in the closed state of the packaging unit, and the rib (22) and groove (32) respectively extend from the free edge (23, 33) of their respective end-walls and have a generally straight longitudinal extension.

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 mould. 
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" elastically. 
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 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 3. 
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 part 3. 
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.degree. 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 unit. 
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.