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The present invention relates to the sector of cardboard
packaging and in particular to a lid for a cardboard carton
according to the preamble of Claim 1.
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Cardboard cartons of this type are used, for example, to carry
goods such as beverages contained in plastic cups closed by a
perforable foil from the production site to the point of sale
(especially to supermarkets and other large retail sites).
Products of this type are formed into groups (comprising six or
twelve products in rows, for example) and these groups are then
stacked like bricks to form more complex structures (two or
three layers of several adjacent groups, for example) which are
then packaged in a cardboard carton.
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The latter is preferably constituted by a base part with sides,
for receiving the products. The base part is then closed by a
lid generally constituted by a central panel (which forms the
top surface of the carton) from which side walls extend to
partly surround the side walls of the base and are secured to
the latter by spots of hot-melt glue.
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Substantially similar cartons can of course be used for other
products, including non-food products.
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However, the use of such cartons does involve some drawbacks,
both structural and functional.
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From a structural point of view, some packaging cartons turn
out to be rather complicated at times because they require the
application of somewhat numerous spots of adhesive in order to
form the base, to close the lid and to couple them.
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Another disadvantage consists in the fact that cartons of the
above type are often superimposed to form stacks, thereby
forming assemblies of considerable dimensions and height, which
are then stored and transported on pallets. This leads to the
cartons, in particular those in the lower positions, being
subjected to considerable mechanical stress, with the result
that they may be deformed, especially outwardly.
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The deformed portions may project from the assembly of cartons
loaded on the pallet, with the risk of causing them to catch on
adjacent stacks and/or on external obstacles, thereby risking
being torn.
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An additional disadvantage consists in the fact that, once the
carton has been opened and the products contained therein have
been removed, both the base and the lid constitute three-dimensional
bodies which, by virtue of the heavy application of
adhesive in order to ensure that they are solid and strong, are
difficult, or at least not easy flatten for disposal. In fact,
in some cases, in order to be flattened, the base and/or the
lid require tough action, which often results in the part being
torn, thereby dispersing fragments or residues.
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The object of the present invention is to provide an
arrangement able to overcome the aforesaid disadvantages.
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This object is achieved according to the present invention by
providing a lid having the characteristics claimed in the
claims which follow. The invention also relates to the carton
to which the said lid is fitted.
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The invention will now be described, purely by way of non-limitative
example, with reference to the appended drawings, in
which:
- Figures 1 and 2 illustrate two successive steps in the
sequence of operations which form a base for coupling with a
lid of the invention;
- Figure 3 illustrates in detail the structure of a lid of
the invention,
- Figure 4 illustrates schematically two successive steps in
the operation for coupling the lid of Figure 3 to a base of a
type illustrated in Figures 1 and 2, and
- Figure 5 shows the carton obtained as a result of this
operation.
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Before a detailed examination of an embodiment of the
invention, it should be stated once again that the invention is
of entirely general application. In the introduction of the
present description, reference was made to a possible
application to the packaging of beverages sold in cups closed
by foil seals: however, the invention could be used in numerous
other packaging applications, both dealing with food products,
such as a bakery goods or fruit and vegetables, or with other
products such as detergents and similar products.
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It must also be said that the assembly of parts, indicated 1 in
Figures 1 and 2, which constitutes - as will be seen more
clearly later - the base of the carton C, illustrated as a
whole only in Figure 5, corresponds to an arrangement which is
known per se and in use in the field of cardboard packaging.
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In substance, the base 1 is preferably constituted of a single
piece of sheet material (typically cardboard, such as
corrugated cardboard, especially in cases in which the carton
is required to have a degree of mechanical strength) in which a
rectangular central panel or base 3, a pair of sides or shorter
walls 4 and a pair of sides or longer walls 5 can be
distinguished.
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The terms "shorter" and "longer" refer to the relative
dimensions of the walls, which are significantly different
since the central panel 3 is rectangular.
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The central panel could, of course, also be square, and would
then have side walls of about the same dimensions. The shape
could also be rectangular but complementary, as it were, to
that illustrated, that is with the two sides constituting the
shorter sides becoming the longer sides and, vice versa, those
shown as the longer sides becoming the shorter. In such a
case, the structure of the sides 4 and 5 would be reversed,
without however having any appreciable effect on the scope of
the invention.
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With a more detailed examination of the structure of the base
1, it will be noted that each of the sides 4 is constituted by
a respective square or rectangular central main portion 41,
with two edge flaps folded over on themselves and glued by
their distal end to the main portion 41. At each lateral edge
of the side 4 (and at each vertical corner of the base 1 as
seen in Figure 2) this produces a corner element or column 42
with an approximately triangular section and reinforcing
projections 43 which extend both along the shorter edges and
along the longer edges of the bottom 3.
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As already stated, all the above follows criteria known per se,
which do not require any further description here.
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In the embodiment illustrated, the sides 5 are generally U-shaped.
They therefore comprise two lateral arms 51, each of
which is in contact, when the respective side 5 is folded
against the corner formations 42, with one of the respective
corner formations 42 of the pair between which the respective
side 5 extends. The two lateral arms 51 of the U shape are
connected to each other by a main portion 52 which is connected
in turn by a fold line to the respective edge (in this case one
of the longer edges) of the central panel 3.
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The main portion 52 is preferably formed, again according to
known criteria, as a double structure - with the obvious aim of
increasing strength and rigidity - by folding over a distal
portion 53 against the proximal portion connected to the
central panel 3.
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Once the corner formations 42 have been formed, and the
portions 53 have been folded against the parts 52, the sequence
of operations to assemble the base 1 calls for the sides 4 to
be arranged perpendicular to the central panel 3 and also the
sides 5.
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In prior art arrangements, the base thus formed is next
consolidated in its final assembled shape, which provides a
concave configuration for receiving the intended products, by
the application of sealing points, typically spots of hot-melt
glue.
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The lid 6 shown in detail in Figure 3 also comprises a central
panel 7, which is rectangular in the embodiment illustrated.
The dimensions of the central panel 7 are preferably identical,
or substantially identical to those of the central panel 3 of
the base 1, since these two elements are intended to constitute
the base surface and the top surface of the finished carton C.
It is conceivable, however, that the dimensions of the central
panel 7 could be greater or smaller than those of the central
panel 3, thereby giving the carton C the general shape of a
truncated pyramid, either narrowing or broadening at the top.
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The central panel 7 of the lid 6 also has two sides 8 along a
first pair of edges (the shorter edges in the embodiment
illustrated) and two other sides 9 along the other pair of
edges (the longer edges in the embodiment illustrated).
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The sides 8 are preferably shaped somewhat like an eyelid, in
the sense that their dimension measured from the fold line 8a
connecting them to the central panel 7 is minimal (preferably
nothing) at the corners of the central panel 7 and increases
gradually (preferably symmetrically with respect to their
central region) to a maximum which is preferably reached around
mid way between the ends of the side or corners and the mid
region of the side.
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Construction experts will immediately appreciate that the
aforesaid shape is closely similar to that of a girder (in a
bridge, for example). This shape is designed to provide the
advantage of maximum resistance to stress (directed primarily
vertically and thus in the plane of the side 8 when it is
folded against the box, as shown in Figure 5) in the central
portion.
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The sides 9, on the other hand, are generally tapered from
their proximal region 90, joined to the central panel 7 along a
fold line 9a.
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The aforesaid tapered shape preferably gives the proximal
portion 90 an approximately trapezoidal shape, with the distal
portion 91 of the side 9 extending as an approximately
rectangular shape from the shorter side of the said trapezoid.
One or more tabs 92 project in a transverse direction from the
distal portion 91. The function of these tabs will be
explained later.
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In Figure 3, the distance between the fold line 9a and the edge
93 of the distal portion 91 of each side 9 of the lid 6 is
indicated d. The choice of the value of this distance d will
also be discussed in detail later.
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The sequence of operation for the application of the lid 6 of
the invention to the base 1 follows criteria which do not
differ substantially from those used to fit lids of the prior
art.
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In substance, the products to be packaged (not explicitly shown
in the drawings) are arranged in the base 1 in one or more
layers on the central panel 3, for example when the base 1 is
still in the condition shown in Figure 2, that is with the
sides 5 still open, away from the corner formations 42.
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The products could, of course also be stacked onto the central
panel 3 at an earlier moment, before the sides 4 are folded
upwards, that is even before they are arranged in the position
shown in Figure 1.
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In principle, it would be possible to arrange the products on
the central panel 3 when the blank to be used to form the base
1 is entirely, or substantially entirely flat, that is before
the folding of the corner formations 42.
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In any case, the actual moment when the products are placed in
the base 1 is not critical to the scope of the invention.
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Starting with a condition such as that shown in Figure 2
(independently of the specific condition of the base 1 when it
has received the products) the lid 6 is fitted by arranging it
over the base 1, substantially in the condition shown in Figure
3. The central panel 7 thus rests on the upper ends of the
corner formations 42 (and on the upper edges of the mid-portions
41 of the sides 4) with the sides 8 projecting over
the upper edge of the said central portions 41 and the sides 9
projecting from the fold line 9a.
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The sides 8 of the lid 6 are then turned down against the
central portions 41 of the sides 4 of the base 1. These sides
8 are then secured in this position by the application, for
example, of staples or of beads of an adhesive such as hot-melt
glue.
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The sides 9 are also folded back against the carton C in two
movements illustrated schematically in an ideal sequence, to
the left and to the right of Figure 4 respectively. It must be
emphasized that this sequence is ideal since the single
movements described hereafter should preferably be carried out
simultaneously and symmetrically on the two sides of carton C.
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In practice, the two movements are as follows:
- folding the sides 9 downwards so that they are aligned
vertically with the edges of the central panel 3: as a result
of this operation, the ends of the proximal portions 90 of each
side 9 (which are generally triangular owing to the trapezoid
shape of the proximal portions 90) are in contact with the
upper ends of the two corner formations 42 between which the
side extends; and
- subsequently folding the sides 5 upwards so that the
arms 51 are in contact with the corner formations 42.
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The overall result thus achieved is the closure of the carton
in the manner illustrated in Figure 5.
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Folding of the sides 5 upwards (to the right in Figure 4) has a
dual effect.
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Firstly, as can be seen more clearly in the lower right-hand of
Figure 5, by folding upwards, the main portions 52 of the sides
5 secure the respective distal portions 91 of the sides 9.
This result is achieved by choosing the distance d (in Figure
3) between the fold line 9a and the edge 93 so that it is at
least slightly greater than the distance (indicated dl in
Figure 5) between the fold line 9a and the upper edge of the
main portion 52 of the associated side 5.
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As an alternative to, or in addition to the arrangement
described above, the sides 5 can be made to secure the sides 9
against the carton by providing the sides 9 with tabs 92,
preferably projecting from their distal portions 91, which can
be inserted (as a result of the folding mechanism shown in
Figure 4) between the corner formations 42 of the base 1 and
the lateral arms 51 of the corresponding folded sides 5.
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In this manner, the sides 9 can be secured against the carton
simply by being hooked to the sides 5 of the base 1, without
the need for fixing points (by staples or beads of adhesive,
for example).
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In order to achieve this result, it is sufficient to secure
(typically with the application of beads of glue) the lateral
arms 51 of the sides 5 and the corresponding corner formations
42, that is two portions of the base 1.
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The overall result of this sequence of operations is the carton
indicated C in Figure 5.
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It will be appreciated that the presence of the lid 6 gives
this carton various advantages over packaging of the prior art.
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Firstly, a cardboard carton is provided which is both simple
and very robust. In particular, it provides considerable
resistance to mechanical stress on the sides 8 which, thanks to
their girder-like conformation, do not tend to bulge outwardly,
even when the carton is subjected to considerable vertical
stress.
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At the same time, the need for fixing elements or points is
reduced to a minimum, both in the case of the lid 6 alone and
in the carton C as a whole. In practice, with the exception of
the points fixing the sides 8 to the sides 4 (points which are
schematically indicated P in Figure 5: it must be remembered
that this illustration is purely schematic, since the points in
question are applied to the face of the side 8 opposite that
which is viewed, and are thus not per se visible), the
respective portions of the lid 6 of the invention have no
attachment elements or points.
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As a result, once the sides 8 are raised and separated from the
sides 4 in order to open the box, the lid 6 consists once again
of a simply folded element of sheet material and is thus easy
returned to its flat state for disposal. This with no need for
detaching any points, with the possible risk of tearing.
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With regard to the base 1, the overall configuration thereof is
no different from that of similar bases of the prior art, the
arrangement of the invention enables the need for closure
points to be kept to a minimum. These can be simply beads or
rings of beads or strips of hot-melt adhesive material, such as
those indicated S in figure 5 alone (it will be recalled, once
again, that this illustration is schematic, since the said
connection elements S are applied to the surfaces which are
hidden from outside view), arranged over the area where the
tabs 92 are inserted between the corner formations 42 and the
arms 51 of the sides 5.
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As a result, operations for the disposal of the base 1 are also
considerably simplified, once the lid has been returned to its
original flat state. All that is required is to "break" the
fixing areas S in order to be able to flatten the base 1 (after
previously flattening the corner portions 42) and possibly
dispose of it.
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Naturally, the principle of the invention remaining the same,
manufacturing details and embodiments may vary widely from
those described and illustrated, without departing thereby from
the scope of the present invention, as claimed in the appended
claims.
