The present invention refers to a multi-functional cardboard box, in particular to a cardboard box which is applicable simultaneously as a container, in particular as a container for food products and as a building element, such as a building element for assembling cardboard furniture.

In the relevant technical field it is known to use paper, cardboard paper or plastic based boxes for storing food products, which apart from their primary application, i.e. storage and delivery of food products can be cleaned in order to be recycled or to be offered for other purposes.

In German patent Nr. DE 100 24 967 a cardboard box for packaging food products - such as pizza or bakery - containing a removable and disposable inner insertion layer is shown. The insertion layer prevents the cardboard box from getting into contact with, and being contaminated by the food product and also prevents the fluids released by the food product to be soaked up by the material of the cardboard box or to drop from inside to the environment. Further, the insertion layer decreases the waste associated with the application of the cardboard box. After disposal of the insertion layer the cardboard box can be reused for packaging and delivery of food products. The insertion layer is made of the same paper or cardboard material like the cardboard box itself.

In document US 591 3443 a liner for protection of a food container is disclosed, which separates the interior of a lunch container from the food content in the container. The liner is comprised of a single continuous piece made of a non-porous material that conforms to the food container and the piece completely covers an interior bottom surface and all interior side surfaces of the container, and at least one adhesive piece is affixed on at least one side of the liner for removable attachment and sealing of the liner material to the container. The adhesive piece has a length substantially equal to that of the side of the liner material on which the adhesive piece is affixed. The liner is made of an absorbent, flexible material. Shape of the liner is preferably rectangular. By tearing off the liner covering the inner surfaces of the food container both the liner and the contamination contained therein can be removed and the container is reusable for storing and delivering food products again. Utility model Nr. DE 700 5841 U discloses a foldable container comprising a bottom tray and an upper cover foldable over the bottom tray, the latter being arranged so that in closed position the walls of the cover surround the walls of the bottom tray. Material of the container is impenetrable for water, e.g. it is made of paper or cardboard coated by plastic on its inner surfaces.

From document DE 782 0603 a container for storing food products which tend to release fluids is known. Onto the inner surface of the container a piece of material with adherent coating can be folded. The coating is formed by high frequency welding of a plastic material such as PVC.

In EP 0 540 482 there is shown a tray applicable for packaging food products, wherein a second, disposable tray can be inserted into the first tray. In patent US 519 0213 a food container being formed entirely from plastic is disclosed. This container, as a result of water repellency of its plastic material, can be washed or rinsed.

In the field of cardboard furniture design it is a common solution to build structures from cardboard box building elements with predetermined shape.

In patent CH 671521 rectangular packaging cardboard containers are applied as building blocks. On the edges of the containers cutouts are formed in which clamping elements can be inserted and with the aid of clamping elements identical rectangular containers as building blocks can be assembled to form various - mainly rectangular - structures.

US 375 2089 discloses a load bearing assembly comprising a horizontal platform mounted on a sub- structure comprising a plurality of vertical hollow units. The units contain a rectangular sheet of substantially rigid material scored along longitudinal lines into rectangular sections and folded and joined to form a box tube unit.

Document AT 404 118 discloses a furniture constructed from at least one cardboard box, and a process for making such cardboard box structure. The cardboard boxes - forming the furniture and having suitable shape - are arranged on top of each other. Vertical walls of neighboring boxes are fixed to each other by means of Velcro-type connecting elements. By this solution a furniture made entirely of recycled material is proposed and the related process can be provided with reduced cost. The present invention aims at providing a multi-functional cardboard box, in particular a cardboard box which is applicable simultaneously as a container for food products (as a primary application) and as a building element for assembling cardboard furniture (as a secondary application).

Object of the present invention is to produce the above mentioned multi-functional cardboard box with high load carrying capacity and esthetically pleasant appearance. With the cardboard box building element of the present invention various furniture designs can be easily conceived and built by the untrained, non-professional end-user.

Further object of the present invention is to produce a recyclable cardboard box, which can be dumped at suitable disposal stations for recycling or reprocessing (can be regarded as third possible use), in case the user decides not to benefit from the secondary application of the cardboard box, i.e. does not exploit the opportunity to assemble cardboard furniture.

According to the present invention the above objects are achieved by a cardboard box container and building element which has a rectangular bottom tray, vertical side walls projecting from the bottom tray and a cover having vertical side walls and being foldable on top of the bottom tray by a pivoting connection, and in closed position of the cardboard box sidewalls of the cover surround sidewalls of the bottom tray from outside or vice versa. The bottom tray, the sidewalls of the bottom tray, the cover and sidewalls of the cover are at least partially provided with fluid resistant, in particular water and grease repellant protective coating on at least part of their inner surfaces. On any of the bottom tray, the sidewalls of the bottom tray, the cover and/or the sidewalls of the cover perforations and/or printed patterns are provided to support secondary application of the cardboard box. The perforations and/or printed patterns form cutting lines or folding lines on the bottom tray, on the sidewalls of the bottom tray, on the cover and/or on the sidewalls of the cover which can be used to form furniture parts like shelves, doors, windows and similar.

As a result of the above features we get a cardboard box which is applicable for storing and delivering food products, and further it can be applied, according to the user's choice, either as a recyclable food container, or due to the prefabricated perforations or printed patterns as a building element for cardboard furniture structures.

In the following description the expression "secondary application" is understood as the additional application of the cardboard box, in particular application as a building element. In the below description with the expression "recycling" we define the case, when the user - disregarding the possible secondary application - dumps the cardboard box at disposal stations exclusively assigned for this purpose.

Further benefits, advantages and features of the present invention become more apparent from the below description of the preferred embodiments, carried out with reference to the drawings, where Fig. 1 is a perspective view of the cardboard box of the present invention,

Fig. 2 is a perspective view of the cardboard box of Fig. 1 with the protective coating against contamination, in

Fig. 3a perforations defining three cutting lines are shown together with perforations defining the openings in which connecting elements can be inserted, in

Fig. 3b perforations defining both cutting and folding lines are shown together with perforations defining the openings for connecting elements, in

Fig. 4 one embodiment of the connecting element for connecting the cardboard box building elements is presented in enlarged view, in

Fig. 5 another embodiment of the connecting element for connecting the cardboard box building elements is presented in highly enlarged view, in

Fig. 6 a structure built up by using cardboard boxes of the present invention is represented.

In Fig. 1 a first preferred embodiment of the cardboard box (1) is shown. The cardboard box (1) has a rectangular bottom tray (2) and the bottom tray (2) contains vertical side walls (3a-3d) extending perpendicular from the plane of the bottom tray (2). A cover (4) with vertical side walls (5a-5c) is pivotally connected to the bottom tray (2). The cover (4) is thus foldable on top of the bottom tray (2). The pivoting connection is effected by an edge (6) extending between a sidewall (3d) the tray (2) and the cover (4). In the closed position of the cardboard box (1) sidewalls (5a-5c) of the cover (4) surround the sidewalls (3a-3d) of the bottom tray (2) from outside (or vice versa), i.e. in closed position sidewalls (5a, 5b, 5c) of the cover and respective sidewalls (3a, 3b, 3c) of the tray (2) are adjacent to each other. Each edge or border line between respective pairs of the bottom tray (2), sidewalls (3a-3d) of the bottom tray (2), cover (4) and the sidewalls (5a-5c) of the cover (4) are provided with perforations so that the respective sidewalls (3a-3d, 5a-5c) can be separated from the tray (2) or cover (4) at the user's choice.

In Fig. 2 the fluid resistant, in particular water and grease repellant protective coatings (12, 13-13d, 14) covering at least partially the inner surfaces of the bottom tray (2), sidewalls (3a-3d) of the bottom tray (2), the cover (4) and/or sidewalls (5a-5c) of the cover (4) are represented. In the cardboard box (1) container food products, like pizza or other hot or cold foods can be stored and/or delivered. In the closed position of the cardboard box (1) the food product can get in contact with the inner surface of either the bottom tray (2), or sidewalls (3a-3d) of the bottom tray (2) or the cover (4). Since contamination caused by the food product would compromise or counteract the secondary application or recycling of the cardboard box (1) due to aesthetical reasons or due to damages caused by fluids released from the food product and soaked up by the box - this way resulting in substantial weakening of the cardboard material - the bottom tray (2), sidewalls (3a-3c) of the bottom tray (2), the cover (4) and/or sidewalls (5a-5c) of the cover (4) are at least partially provided with fluid resistant, in particular water and grease repellant protective coatings (12, 13a- 13d, 14) on their inner surfaces (in the view of Fig. 2 inner surfaces of wall 3b and 3c cannot be seen, however, arrows indicate the position of the respective 13b and 13c coatings).

The material of the fluid resistant coating (12, 13a-13d, 14) can be for example waxed paper, plastic, such as PVC, PE or PP, silicon coated paper or greaseproof paper or silicon based foil or any other suitable material used in the relevant field, which according to current standards may get in contact with food products. The fluid resistant coating (12, 13a-13d, 14) is releasably bonded to the whole or to a partial area of the inner surface of the bottom tray (2), sidewalls (3a-3d) of the bottom tray (2) and/or the cover (4) of the cardboard box (1). Adhesion can be effected by adhesives or welding processes, e.g. by high temperature welding, hot melt type adhesives, double sided adhesives etc. The adhesive layer or welding seam is denoted by reference number 122 in Fig. 2. It is also conceivable to fix the resistant coating (12, 13a-13d) within the cardboard box (1) simply by folding around respective sidewalls (3a-3d, 5a-5c).

Alternatively, bonding of the inner coating (12, 13a-13d, 14) can simply be achieved by any mechanical means, such as by clamps or staples (not shown). The releasably bonded coatings (12, 13a-13d, 14) - when primary use as a food container is over - can be removed by tearing or cutting. In a further embodiment (not shown) the fluid resistant coating (12, 13a-13d, 14) is not adhesively bonded to the cardboard box (1). In this case a closed, perforated bag containing the food product is placed inside the cardboard box (1). The material of the fluid resistant bag can be for example waxed paper, plastic, such as PVC, PE or PP, silicon coated paper or silicon based foil or any other suitable material used in the relevant field. In view of the secondary application and/or recycling the most important feature is that the weight and cost of the coatings (12, 13a-13d, 14) - or the closed, perforated bag - are considerably lower than that of the whole cardboard box (1). Thus, it is advantageously achieved that at the beginning of the secondary application no significant amount of waste is produced.

In Fig. 3a perforations (7a, 7b) formed on the cardboard box are shown. The bottom tray (2) of the box is provided with perforations (7a) facilitating the secondary application of the cardboard box (1) and making possible modification of the shape of the box (1) by tearing and cutting along said perforations (7a). Same perforations (7a) can be formed on sidewalls (3a-3d) and on the cover (4). Furthermore, each sidewall (3a-3d) of the bottom tray (2) and each sidewall (5a-5c) of the cover (4) and the cover (4) itself are provided with perforations (7b) facilitating the secondary application of the cardboard box (1). Perforations (7b) indicate the positions of openings (8) in which - after tearing off or cutting out the perforations (7b) - connecting elements (90) for fastening the cardboard box can be inserted. Same perforations (7b) can be formed on the bottom tray (2) as well.

The shape of the perforations (7a, 7b) can be different depending on the intended building structure. In the present embodiment in Fig. 3a a cardboard box (1) is shown from which an open shelf can be formed by cutting out the cardboard material along the depicted three perforating (7a) lines. In order to achieve this result the perforating (7a) lines are running parallel with walls (3a, 3b and 3c) of the bottom tray (2) and are engraved into the tray (2) at about 2-3 cm distance from each respective wall (3a, 3b, 3c). Along such perforations (7a) the cardboard material can be cut out, made open and its content is rendered accessible. Any desirable pattern can be cut out by the perforations (7a).

In Fig. 3a perforations (7a, 7b, 7c, 7d) formed on the cardboard box (1) are shown. The bottom tray (2) of the box is provided with perforations (7a, 7c) facilitating, similarly to the embodiment of Fig. 1, secondary application of the cardboard box (1) and making possible modification of the shape of the box (1) by tearing and cutting along said perforations (7a) and folding along the second type of perforations (7c). Same perforations (7a, 7c) can be formed on sidewalls (3a-3d) and on the cover (4). In the embodiment of Fig. 3b a cardboard box (1) is shown from which a double door can be formed. To this end, the cardboard material of the bottom tray (2) is provided with perforating (7a, 7c) lines running parallel with walls (3a, 3b and 3c) of the bottom tray (2) and being engraved into the tray (2) at about 2-3 cm distance from each wall (3a, 3b, 3c), and has a further perforation (7a) extending along the symmetry axis of the tray (2). Along the first type of perforations (7a), i.e. the perforation (7a) overlying in the symmetry axis and the perforation (7a) extending perpendicular to the symmetry axis and running parallel with sidewall (3d), the cardboard material can be cut, whereas the second type of perforations (7c) serve as folding lines. Any further arbitrary configuration of the perforations (7a, 7c) is conceivable according to which shelves, windows, doors and other furniture parts can be formed and any desirable pattern can be obtained by cutting out and folding the perforations (7a, 7c). In Fig. 3b two different types of perforations (7b, 7d) defining the openings (8) for the insertion of connecting elements (90, 9) are shown in detail. From the two different perforations (7b, 7d) in general only one is present on a single cardboard box (1), since a given sort of perforation (7b or 7d) entails the use of a predetermined type of connecting element (90, 9). In this embodiment perforations (7b, 7d) are engraved into each sidewall (3a-3d) of the bottom tray (2), each sidewall (5a-5c) of the cover (4) and the cover (4) itself and facilitate the secondary application of the cardboard box (1). Perforations (7b, 7d) indicate the positions of openings (8) in which connecting elements (90, 9) of the cardboard box (1) can be inserted. Perforations (7b, 7d) can be removed by tearing or cutting, no folding is foreseen in this case. By proper folding and shaping of the sheets of the cardboard box (1), i.e. the bottom tray (2), the cover (4), sidewalls (3a-3d) of the tray (2) or sidewalls (5a-5c) of the cover (4) - the openings (8) for the engagement of connecting elements (90, 9) are placed adjacent to each other and the connecting elements (90, 9) can be lead through more adjacent sheets of the box, thus, the sheets can be held in fixed position.

Connecting elements (90, 9) are available in the form of mechanical connectors for the connection of a series of cardboard boxes (1) and can be provided as auxiliary accessories in a separate package or packages.

In Fig. 3c and 3d the cardboard material of the bottom tray (2), the sidewalls (3a, 3c, 5a, 5c) and the cover (4) is provided with lines (17) of a printed pattern. The lines (17) forming the printed pattern can extend through more walls of the cardboard box (1) and can be used as cutting lines, which can be cut out for example by a suitable knife or other cutting means, or the lines (17) of the printed pattern may serve as folding lines. A single cardboard box (1) may contain more groups of printed patterns foreseen for different secondary applications, i.e. one group for a shelf, one for a table etc. and in this case the different printed patterns are printed in different colors. As a concrete example, the cardboard box (1) of Fig. 3c is suitable to erect a table, the cardboard box (1) of Fig. 3d is suitable to construct a tabletop or a picture frame. We note here that in these cases there is no need for connecting elements, the cut and folded elements can be engaged in each other at the proper adjacent connection lines. In certain cases to construct the intended furniture structure the bottom tray (2) and cover (4) of the cardboard box (1) can be folded inside out.

The connecting elements (90, 9) can be for example staples, pins or spikes, connectors containing mating plug and socket type elements, clamping elements, snap fitting connectors and the like. Particular examples of the connecting elements (90, 9) are shown in Figs. 4 and 5.

Fig. 4 is a schematic representation of a possible embodiment of a first connecting element (9) for connection of adjacent cardboard boxes (1). This element (9) is designed to have three arms (91) being directed in 120° with respect to each other in a plane perpendicular to a longitudinal axis (T) of the connecting element (9) and three bars (92) extending from the respective ends of the arms (91) parallel to said longitudinal axis (T). The arms (91) and bars (92) of the connecting element (9) can be selectively boken down; in this way coupling and fixing of adjacent sheets of the cardboard box (1) can be realized by only two arms (91) or bars (92). It is not excluded to have an embodiment, where the connecting element (9) - for the sake of more durable fastening - comprises more than three arms (91) and bars (92). In this case the respective angles between the arms (91) can deviate from 120° (and may be not equally distributed).

In cooperation with the connecting element (9) along the bottom tray (2), the sidewalls (3a-3d) of the bottom tray (2), the cover (4) and the sidewalls (5a-5c) of the cover (4) openings (8) are provided which facilitate insertion of the bars (92) of the connecting elements (9). Positions of the openings (8) are defined (see Fig. 3b) by perforations (7d) having the same diameter as the bars (92). Since here the number of arms (91) and bars (92) is three, the respective number of openings (8) is also three. In case of connecting elements (9) with higher number of arms (91) and bars (92) the number of necessary openings (8) is higher. This means that on the respective sidewalls (3a-3d) of the tray (2) and sidewalls (5a-5c) of the cover (4) the number of perforations (7d) is accordingly higher. It is not excluded, however, to apply a connecting element (9) with only two arms (91) and mark on the box only two perforations (7d) for the intended openings (8). The diameter of the openings (8) provided for the first connecting element (9) is 2-5 mm.

Fig. 5 is a schematic representation of a possible embodiment of a second connecting element (90) designed to connect adjacent cardboard boxes (1). The second connecting element (90) has a cylindrical body (93) symmetrical with respect to a longitudinal axis (T), and one end of the body (93) is provided with a plug (95) and the opposite end of the body (93) is provided with a socket (96) type connector part. In the embodiment of Fig. 5 two connecting elements (90) are shown next to each other. The plug (95) of the body (93) of the left connecting element (90) can be tightly engaged into the socket (96) of the body (93) of the right connecting element (90). The plug (95) and socket (96) type parts of the body (93) of the cylindrical connecting element (90) can be engaged for example by snap fit connection, screwing or bayonet-type coupling. On the periphery of the body (93) a recess (94) running around the body (93) in the circumferential direction is formed. The recess (94) can be formed in the body (93) e.g. by milling in about 1-3 mm thickness. The diameter of the recess (94) is thus smaller than the diameter of the rest of the body (93).

In cooperation with the connecting elements (90) along the bottom tray (2), the sidewalls (3a-3d) of the bottom tray (2), the cover (4) and the sidewalls (5a-5c) of the cover (4) openings (8) are provided which facilitate insertion of the cylindrical body (93) of the connecting element (90). These openings (8) defined by perforations (7b) have the same diameter as the recess (94) formed on the cylindrical body (93). Diameter of the openings (8) is relatively large, in this embodiment 5-12 mm. Each connecting element (90) needs to be associated with one respective opening (8). With the above arrangement it is advantageously achieved that the body (93) of the connecting elements (90) is tightly fastened into the openings (8). ln Fig. 6 there is shown a structure made up of several cardboard boxes (1) as building elements. In this embodiment a shelf unit having five closed sidewalls and an openable door is shown. The shelf unit is configured so as its upper side and two of its sidewalls is composed of bottom trays (2) - of three cardboard boxes (1) - and its backside and front side is composed of covers (4) of respective cardboard boxes (1). Bottom part of the shelf can be composed for example by an upper wall of a second shelf unit having the same structure. From the cover (4) constituting the front side of the shelf unit the sidewalls (5a-5c) can be removed along the perforations being provided on the edges (which have no separate reference number). The cover (4) constitutes a door by being pivotally connected to the sidewall (3d) and being able to rotate around edge (6). The cover (4) can be closed to a position facing the opposite sidewall (3b) - which sidewall (3b) may be part of another cardboard box (1) building element.

The shelf is fastened and held in place by connecting elements (90). Connecting elements (90) may be lead through the openings arranged on the bottom tray (2) forming the upper side of the shelf unit and sidewalls (3a, 3c) of the respective cardboard box (1) building elements. Other parts of the shelf are to be fixed in similar manner. Depending on the intended structure, i.e. the possible attachment of the shelf units the connecting elements (90) can be directed in different directions than what is shown here. In the present embodiment plugs (95) projecting from a bottom part of a possible second shelf unit (not shown) can be engaged into corresponding sockets (96) of the connecting elements (90) positioned in the upper side of the shelf. Cylindrical connecting elements (90) can be replaced by the first type of connecting elements (9) with arms (91) and bars (92).

It is evident that in order to improve strength of the structure more than two connecting elements (90, 9) may be positioned along the sidewalls (3a, 3c). In the present example in Fig. 6 this number is three.

Strength and durability of the structure can be increased by other means as well, e.g. with the aid of stiffening elements. For this purpose sidewalls (3a-3d, 5a-5c) are removed or torn off from the corresponding bottom tray (2) and cover (4) along the edge perforations. Sidewalls (3a-3d) and sidewalls (5a-5c) can be used for example as ridges running inside the cardboard boxes (1) parallel with edges of the bottom tray (2) or the cover (4). Alternatively, they can extend under a predetermined angle, such as 45° with respect to the edges and span between for example the opposite corners (this embodiment is not represented).

According to a further aspect of the invention a process for assembling the above described cardboard box (1) is provided, wherein in the course of the process first a cardboard box (1) is provided, which has a rectangular bottom tray (2), the bottom tray (2) having vertical sidewalls (3a- 3d), and a cover (4) having vertical sidewalls (5a-5c) and being foldable on top of the bottom tray (2) is pivotally connected to the bottom tray (2), and in closed position of the cardboard box (1) sidewalls (5a-5c) of the cover (4) surround sidewalls (3a-3d) of the bottom tray (2) from outside, in the next step perforations (7a-7d) and/or lines (17) of a printed pattern are formed on the bottom tray (2), on sidewalls (3a-3d, 5a-5c) and on the cover (4) of the cardboard box (1) to support secondary application of the cardboard box (1) container, then the bottom tray (2), sidewalls (3a-3d) of the bottom tray (2) and the cover (4) are at least partially provided with fluid resistant, in particular water and grease repellant protective coating (12, 13a-13d, 14) on their inner surfaces, thereafter the cardboard box (1) is applied (as a primary application) for storage and/or delivery of food products; following the primary use the fluid resistant, in particular water and grease repellant protective coating (12, 13a-13d, 14) can be removed from the inner surfaces before starting the secondary application of the cardboard box (1), the secondary application comprising of cutting and/or folding the perforations (7a, 7c) and/or the lines (17) of the printed pattern to form furniture parts like shelves, doors, windows and similar. If the furniture is constructed on the basis of lines (17) of the printed pattern no connecting means are necessary, and construction can be completed by simple cutting and folding actions. If connecting elements (90, 9) are needed to the actual design cutting of perforations (7b, 7d) is essential to form openings (8) in which connecting elements (90, 9) can be inserted and in this case the furniture parts are fastened with the aid of connecting elements (90, 9).

According to a further preferred aspect of the invention the predetermined secondary application of the cardboard box (1) is not exploited. During this process we carry out the same steps as we did in case of the above procedure, however, after using the cardboard box (1) for the first application and removing the fluid resistant, in particular water and grease repellant protective coating (12, 13a-13d, 14) from the inner surfaces of the bottom tray (2), sidewalls (3a-3d) of the bottom tray (2) and the cover (4) we do not proceed with secondary application of the box, i.e. the application as a cardboard box building element, instead we can dump the cardboard box (1) at a disposal station exclusively assigned for this purpose (for example by an exclusive owner of the rights) to recycle the cardboard box (1) container, and finally we may apply the cardboard box (1) again but not exclusively for storage and/or delivery of food products.