Packaging box comprising a cardboard bottom and a transparent lid

A packaging box comprising a cardboard bottom and a transparent lid removably mounted on the opening of the bottom. The lid comprises a convex portion facing inside the box and cooperating with the opening of the bottom and at least two flaps articulating on opposite edges of the lid. Each overlapping at least partly a side face of the bottom. The flaps each comprise at least locking elements cooperating with complementary locking elements provided in one side face of the bottom or with complementary locking elements born by the other flap auxiliary flaps articulated on the other edges of the lid. The invention is applicable to the packaging of food products.

FIELD OF THE INVENTION
 The present invention relates to a packing box for products, in particular
 food products such as pastries.
 BACKGROUND OF THE INVENTION
 Packaging boxes conventionally used in the food trade are generally made of
 a cardboard blank, cut out, bent and cemented. Such boxes conventionally
 are not usable in industry and for the distribution of foodstuffs because
 of their cost of production and filling. Moreover, this type of package
 does not permit the enclosed product to be seen.
 There have been developed boxes that are entirely of transparent or
 translucent material, permitting overall direct viewing of the contained
 product.
 However, such boxes are not suitable for high-class contents such as for
 example pastries, because of their poor and relatively cheap appearance.
 It is thus preferred to use boxes whose bottom is of cardboard and on which
 has been placed a transparent film or cover arranged to fit onto the
 bottom.
 So as to obtain viewing of the contents, the cover can comprise a window on
 top closed by a transparent or translucent film. The cover can also be
 made entirely of transparent or translucent plastic material. However, in
 this latter case, the production of such covers and their emplacement are
 not easy. Moreover, there is not always obtained a locked closure of said
 cover on the bottom, the cover being simply placed over the bottom.
 There has been proposed, in Belgian patent BE-A-572 970, a box constituted
 of a bottom on which is disposed and locked a cover having a shape
 corresponding to the opening of the bottom of the box and which comprises
 two flaps articulated on opposite corners of the cover. These flaps can
 cover totally the side faces of the bottom and thus have respectively an
 edge of their own disposed below the bottom, the bottom thus having on its
 side surfaces retaining plates whose lower portion extends below the
 bottom so as each to constitute a retaining element in which can be fixed
 the flexible edge of each flap of the cover provided with a groove
 adjacent of the bend between the flap and the edge.
 According to another embodiment, in the absence of a retaining plate, the
 edge is bent into V-shape and is disposed below the bottom or else a
 retaining plate is provided along all the lengths of the lateral surface
 to serve as an abutment to the free end of the edge bent in a V. The
 articulated flaps can also partially cover the lateral surfaces of the
 bottom and more precisely the upper edge of said lateral surfaces. These
 flaps thus have an edge co-acting with an edge of the opening of the
 bottom by the horizontally projecting opening of the bottom provided at
 the upper end of the lateral surfaces.
 In this type of box, it is thus necessary, to obtain good closure, to
 provide locking means for the flaps carried by the bottom which are always
 projecting from one lateral surface either at its upper end or at its
 lower end. These locking means provided on a corner of a lateral surface
 of the bottom are not always simple to make.
 SUMMARY OF THE INVENTION
 So as to overcome these drawbacks, there is proposed a packaging box whose
 cover of transparent or translucent plastic material is easily produced
 and whose closure is simple and easy because of the simple and easy
 emplacement of the cover on the box, the closure being adapted also
 moreover to be locked.
 To this end, the invention has for its object a packaging box of the type
 comprising an open cardboard bottom of parallelepipedal shape and a
 transparent or translucent cover mounted removably on the opening of said
 bottom, characterized in that the cover comprises an embossment turned
 inwardly of the box and co-acting with the opening of the bottom as well
 as at least two flaps articulated on opposite edges of the cover, each
 covering at least partially a lateral surface of said bottom, said flaps
 moreover each comprising at least one locking means co-acting with a
 complementary locking means provided in a side surface of the bottom or
 with complementary locking means carried by the other flap or auxiliary
 flaps articulated on other edges of the cover.
 Thus, upon emplacement of the cover on the bottom, there is ensured a
 closing of the box by the co-action of the locking means carried by the
 flaps with the complementary locking means provided on the bottom and/or
 on the other flaps of the cover.
 The bottom is preferably made of cardboard in the conventional way, and it
 can be of the "automatic" type, that is, re-bendable.
 The cover is preferably constituted by thermo-forming a plastic material,
 elastically deformable, transparent or translucent. It is present in the
 form of a parallelepipedal corresponding to the opening of the bottom.
 Thus, according to a first embodiment, the cover comprises a protrusion
 turned inwardly of the box when the cover is emplaced on the bottom and at
 least two opposite flaps provided each with locking means co-acting with a
 complementary locking means provided in each lateral surface of the base
 that the flaps cover at least partially.
 According to a modification, the cover preferably comprises two opposite
 flaps covering respectively entirely a lateral surface of the bottom, each
 flap having at its lateral ends, end tongues articulated about the corners
 of the bottom, each end tongue partially covering the adjacent lateral
 surface and each tongue having moreover a locking means co-acting with a
 complementary locking means provided on said adjacent lateral surface of
 the bottom.
 Preferably, the locking means are of the tongue/slot type, known per se,
 and, in the case of the modified embodiment, they are provided
 respectively on the end tongues of the flaps of the cover and on the ends
 of the side surfaces of the bottom which are not covered by the flaps of
 the cover.
 This modification permits providing recesses in the side surfaces of the
 bottom covered by the flaps of the cover so as to offer greater visibility
 of the product contents, said flaps being adapted to have embossments
 engaging in said recesses. In this manner there is assured good
 emplacement of the cover on the bottom.
 In this embodiment, the closing of the box is obtained by the emplacement
 of the cover and the co-action of the locking means of said cover and of
 the bottom. The locking of the closure is obtained simultaneously to the
 closure itself by cooperation of the locking means of the flaps and of
 those of the bottom.
 According to a second embodiment of the invention, the cover comprises at
 least two opposite flaps, each of the flaps being provided with locking
 means co-acting with a complementary locking means provided on the other
 flap or on an auxiliary flap of the cover so as to ensure closure of the
 cover on the bottom.
 Thus, the emplacement of the abutment of the cover on the opening of the
 bottom permits good positioning and the closure is obtained simply by
 assembling the cover on the bottom by co-action of the locking means of
 the flaps which extend along lateral surfaces of the bottom. There is
 accordingly no need to encase the cover along the lateral walls of the
 bottom, which greatly facilitates closure of the box.
 In this embodiment, each of the flaps comprises preferably an embossment as
 such to engage in a recess provided on the surface of the bottom covered
 by said flap so as to obtain among other things a locking of the closure
 of the box by engagement of said embossments in the windows of the bottom.
 According to a first modification of this embodiment, the two flaps of the
 cover have, at their side ends, lateral prolongations articulated on the
 edges of the bottom, the two lateral prolongations of the first flap of
 the cover partially covering the adjacent surfaces and the two lateral
 prolongations of the second flap of the cover also covering partially the
 same surfaces, said lateral prolongations being arranged to cover said
 surfaces, one of the prolongations comprising a locking means co-acting
 with a complementary locking means provided on the other said
 prolongation.
 Thus, upon locking the lateral prolongations, the cover is closed on the
 bottom, the embossments of the flaps being moreover engaged and maintained
 in their recesses in the surfaces of the bottom so as to lock the box
 closed.
 The lateral prolongations can be shaped so as to form, upon locking, an
 embossment adapted to engage in an opening provided in the lateral side of
 the bottom that they cover. Thus, there can be used a bottom having an
 opening on each side surface.
 In this manner, the co-action of the locking means of a flap with the
 complementary locking means of the other flap permit easy closure of the
 box, locking of this closure being obtained by the engagement of the
 embossments of the flaps in the windows of the bottom.
 According to a second modification of this embodiment, one of the flaps of
 the cover is provided at its side ends with two lateral prolongations
 pivoted on the edges of the bottom and adapted to cover totally the two
 adjacent lateral surfaces, each side prolongation comprising an end tongue
 articulated about an edge of the bottom and partially covering the second
 flap of the cover, each end tongue having a locking means co-acting with a
 complementary locking means provided on the second flap of the cover.
 In this case as well, the bottom can comprise an opening on each lateral
 surface, each lateral prolongation being adapted to have a complementary
 protrusion thus ensuring the locking of the closure of the box.
 According to a third modification of this embodiment, the cover has four
 flaps articulated on the edges of the cover, two opposite flaps having at
 their lateral ends an end tongue articulated on an edge and partially
 covering the adjacent auxiliary flaps, said end tongues having
 respectively locking means and the two adjacent auxiliary flaps having at
 their lateral ends a complementary locking means.
 Preferably, in this embodiment, the locking means carried by a flap are
 tongues, the complementary locking means carried by the other flap or an
 auxiliary flap being slots.
 It can also be provided that each flap of the cover has an end tongue
 provided with locking means co-acting with a complementary locking means
 provided at the end of the adjacent flap which covers the end tongue and
 has a complementary locking means at its other end adapted to co-act with
 a locking means carried by the end tongue of the other adjacent flap.

DESCRIPTION OF THE PREFERRED EMBODIMENTS
 As can be seen in FIG. 1, a box according to the invention comprises a
 cover 1 and a bottom 2.
 The bottom 2 of cardboard has an open parallelepipedal shape and comprises
 four side surfaces 4, 4' and 8, 8'.
 The cover 1 is made by thermo-forming an elastically deformable plastic
 material and is prolonged by two flaps 3, 3' which, when the cover 1 is
 emplaced on the bottom 2, cover respectively partially the two opposite
 surfaces 4, 4' of the bottom 2. Each flap 3, 3' comprises a tongue 5
 lockable in a slot 6 provided at the same position on each surface 4, 4'.
 On the external surface of the cover 1 is formed a rib forming an
 embossment 7 which constitutes an abutment member against the periphery of
 the edges of the opening of the bottom 2, thereby ensuring good
 emplacement of the cover 1 on the bottom 2.
 So as to close the box, it suffices to emplace the cover 1 and to introduce
 the tongues 5 into the slot 6 so as to lock the closure.
 In FIG. 2, the flaps 3, 3' have dimensions suitable to cover totally the
 surfaces 4 and 4' of the bottom 2. Each flap 3, 3' comprises two end
 tongues 9. Upon emplacement of the cover 1 on the bottom 2, the flaps 3
 and 3' cover the surfaces 4 and 4' and the end tongues 9 articulated on
 the edges of the bottom 2 partially cover the two adjacent surfaces 8 and
 8' of the bottom 2. Each end tongue 9 is provided with a tongue 5
 co-acting with a slot 6 provided at the same place at each end of the
 surfaces 8 and 8' of the bottom 2.
 Preferably, the openings 10 in the surfaces 4 and 4' of the bottom 2, the
 flaps 3 and 3' being provided with an embossment 11 corresponding to said
 openings 10 such that, when the flap 3 or 3' covers the surface 4 or 4',
 the embossment 11 engages in the opening 10.
 FIGS. 3, 4 and 5 show the second embodiment of the invention.
 In FIG. 3, the flaps 3 and 3' are provided with embossments 11 adapted to
 engage in openings 10 provided in the surfaces 4, 4' of the bottom 2 that
 they cover.
 The flaps 3, 3' are moreover provided, at their side ends, with
 prolongations 12, 12'. Thus, although the flaps 3, 3' cover the surfaces
 4, 4', the lateral prolongations 12 and 12' of the flaps 3 and 3'
 partially cover the two adjacent surfaces 8 and 8' of the bottom 2. A
 lateral prolongation 12 and a lateral prolongation 12' extending along a
 same surface 8 or 8' of the bottom 2 are so dimensioned as to overlap, one
 comprising a tongue 13 and the other a slot 14.
 Upon locking the lateral prolongations 12 and 12', the embossments 11 of
 the flaps 3, 3' are engaged in the openings 10 of the surfaces 4, 4'.
 Thus, the cover 1 is retained on the bottom 2 by means of the embossments
 11 engaged in the openings 10, the closure of the box obtained by the
 co-action of the locking means of the flaps 3, 3' is thus perfectly
 locked.
 In this embodiment, it is possible to provide a bottom 2 of which all the
 surfaces 4, 4', 8 and 8' are provided with openings 10, the lateral
 prolongations 12, 12' being shaped so as to form, upon their locking on
 the surfaces 8 and 8', an embossment 15 engaging in the opening 10 of said
 surfaces 8 and 8'.
 According to the modification of the second embodiment shown in FIG. 4,
 only the flap 3 is provided with lateral prolongations 16 adapted to cover
 the adjacent surfaces 8 and 8'. Each lateral prolongation 16 comprises at
 its longitudinal end, an end tongue 17 adapted partially to cover the end
 of the adjacent flap 3'. Each end tongue 17 comprises a tongue 18
 co-acting with a slot 19 provided at the same position on the flap 3'.
 The lateral prolongations 16 can also comprise an embossment 20 adapted to
 engage in an opening 10 provided on each surface 8, 8' of the bottom 2
 which thus comprises four openings 10.
 In FIG. 5, the cover 1 comprises four flaps 3, 3', 30, 30', the two
 opposite flaps 3, 3' comprising end tongues 31 partially covering the ends
 of the two auxiliary flaps 30, 30' respectively articulated on the edges
 of the cover which do not comprise flaps 3, 3'. Each end tongue 31 has a
 tongue 32 co-acting with a slot 33 provided at each end of the adjacent
 flaps 30, 30'.
 Preferably, the locking of the closure of the box is ensured by engagement
 of the embossments 11 provided on each flap 3, 3' and the embossments 34
 provided on the flaps 30 and 30' in openings 10 provided on each lateral
 surface 4, 4', 8 and 8' of the bottom 2.
 A box according to the invention therefore offers the advantage of being
 adapted to be easily closed, the cover being adapted to be locked on the
 bottom, of being also equally easy to open, the means being reversible, of
 being simple in construction, and easy to store before use, the cover in
 particular being stackable and the bottom being adapted to be folded.