EP2174573A1

EP2174573A1 - Expanding device for self-expandable foldable display case and self-expandable foldable display case

Info

Publication number: EP2174573A1
Application number: EP08787591A
Authority: EP
Inventors: Francisco Lopez
Original assignee: Mestres Armengol Ferran
Current assignee: Mestres Armengol Ferran
Priority date: 2007-06-06
Filing date: 2008-06-05
Publication date: 2010-04-14
Also published as: ES2310135A1; WO2008148916A1; ES2310135B1

Abstract

The display case comprises a foldable structure (10) with two panels (11, 12) facing one another and attached at the side edges thereof. Between the panels of the structure (10) there is an expanding device comprising a first laminar body (30) with opposed first and second edges (31, 32) and at least one insertion portion (34) extending between at least one intermediate stop edge (33) and one of said first and second edges, and a second laminar body (40) with opposed first and second edges (41, 42) and a slot (43) between said first and second edges. The insertion portion is inserted in the slot and the slot (43) and the stop edge (33) define a fulcrum line along which the first and second laminar bodies (30, 40) can rotate with respect to one another towards an expanded position in cooperation with an elastic band (5).

Description

Field of the Art

The present invention relates to an expanding device made from two laminar bodies, of a material such as cardboard, corrugated cardboard, plastic, and corrugated plastic, among others, applied to the expansion of a self-expandable foldable display case formed by two or more panels facing one another and attached at the side edges thereof, and which in a collapsed situation adopt a planar configuration, and in a service position adopt a three-dimensional configuration capable of standing upright.
The present invention also relates to a self-expandable foldable display case equipped with such expanding device.

Background of the Invention

International patent application WO 2006/067252 A1 discloses a collapsible self-expandable display case and a push element for the expansion thereof. This display case comprises a structure formed by two or more panels facing one another and attached at the respective side edges thereof by means of elastic bands hooked in protruding flanges of the panels. The structure can be arranged in a collapsed situation, in which it adopts a planar configuration, and from said collapsed situation, and in cooperation with expansion means including one or more push elements driven by one or more elastic pull elements, the display case can automatically pass to a service position in which the structure adopts a three-dimensional configuration capable of standing upright. Furthermore, from said collapsed situation, the display case can be folded through transverse fold lines to a folded situation. Each push element of said expansion means is in the form of a laminar body attached to one of the panels of the structure and capable of adopting a planar position together with the panels of the structure in said collapsed situation, and the pull element is in the form of an elastic band with one of its ends hooked in a hooking configuration formed in the laminar body and arranged to rotate, curve or bend the laminar body between the panels of the structure and thus cause the expansion of the display case.
This collapsible self-expandable display case and push element of international patent application WO 2006/067252 A1 is fully operative. However, it is susceptible of several improvements in relation to a reduction in the number of separate elements forming it, and in the number of operations necessary for the production of its components and assembly thereof.

Disclosure of the Invention

According to a first aspect, the present invention provides an expanding device for a self-expandable foldable display case. The self-expandable foldable display case is of the type comprising a structure formed from at least two panels facing one another and attached at the side edges thereof, and which in a collapsed situation adopt a planar configuration, and in a service position adopt a three-dimensional configuration capable of standing upright. The expanding device is of the type comprising at least one laminar body attached to at least one of said panels, said laminar body being capable of adopting a planar position together with the panels in said collapsed situation, and a pull element arranged to rotate, curve or bend the laminar body between the panels, and thus cause the expansion of the structure of the display case. The expanding device of the present invention is characterized in that it comprises two laminar bodies, namely: a first laminar body having opposed first and second edges and at least one insertion portion extending between at least one stop edge located between said first and second edges and one of said first and second edges; and a second laminar body having opposed first and second edges and at least one slot located in an area between said first and second edges. The mentioned insertion portion of the first laminar body is sized to be inserted in said slot of the second laminar body until said stop edge of the first laminar body makes contact with the second laminar body. In this position, the stop edge of the first laminar body and the slot of the second laminar body define a fulcrum line along which the first and second laminar bodies can rotate with respect to one another between a planar position, in which the first and second laminar bodies are superimposed, and an expanded position, in which the first and second laminar bodies are crossed.
The first and second laminar bodies are of a relatively rigid laminar material, such as for example cardboard, corrugated cardboard, plastic, or corrugated plastic, among others, although a corrugated cardboard is generally preferred. When corrugated plastic or cardboard is used, the grooves provided by the corrugations are arranged in a direction perpendicular to the mentioned fulcrum line, i.e., extending between the first and second edges of each laminar body.
For the attachment of the expanding device to the structure of the display case, from at least one of the first and second edges of the first and second laminar bodies there extends at least one attachment flange configured to be attached, for example by an adhesive, to an inner face of one of the panels of the structure. The mentioned attachment flange is connected to the corresponding first or second laminar body by a fold line facilitating the movements of the laminar body involved. In general, those push edges of the laminar bodies which are not associated with an attachment flange slide on the inner face of one of the panels of the structure of the display case during the expansion and collapsing processes of the display case. Depending on the number of panels and/or on the configuration of the structure of the display case, an attachment flange can be provided in one push edge of each laminar body of the expanding device for the attachment to two different panels of the structure of the display case, or even the four push edges of the two laminar bodies can be associated with respective attachment flanges for the attachment to four different panels of the structure of the display case.
In the simplest embodiments, the pull element of the expanding device comprises a single elastic band hooked by one of its ends in a first hooking configuration formed in the first laminar body and a second end hooked in a second hooking configuration formed in the second laminar body. The mentioned elastic band is thus tensed when the expanding device is arranged in the planar position, and is arranged to pull the first and second laminar bodies towards the expanded position.
For the purpose of limiting the rotation of the first and second laminar bodies so that in the expanded position they are approximately at a right angle with respect to one another, or forming any other angle considered to be suitable, at least one of the laminar bodies comprises a limiting appendage capable of making contact with the other one of the laminar bodies when the expanding device is in the expanded position. Advantageously, the same laminar body incorporating the slot furthermore has a cut defining the mentioned limiting appendage and also the second hooking configuration in the limiting appendage, with a proximal end (i.e., closer to the laminar body) of the limiting appendage connected to the first laminar body by a fold line facilitating the movements of the limiting appendage in relation to the laminar body. The elastic element is hooked in the first and second hooking configurations such that the limiting appendage is linked with the elastic element and rises together with the latter as the expanding device progresses from the planar position towards the expanded position. Furthermore, the limiting appendage has a distal edge (i.e., farther from the laminar body to which it is attached) wider than the first hooking configuration formed in the other laminar body, and a portion of the elastic band adjacent to the first hooking configuration makes contact with said distal edge of the limiting appendage preventing an subsequent movement thereof during the progress of the expanding device from the planar position to the expanded position to establish the limit position of the limiting appendage corresponding to the expanded position.
In this expanded position, the expanding device has, with only two crossed laminar bodies, a three-dimensional configuration with a large volume, with up to four edges, i.e., the first and second edges of the first laminar body and the first and second edges of the second laminar body, maximally separated and arranged to press against the two or more panels of the structure of the display case from the inside to expand it. Furthermore, the mentioned fulcrum line is located in an approximately central section of the two sheets, which involves that each laminar body has in practice two lever arms of substantially the same length, one between the fulcrum line and the first edge and the other one between the fulcrum line and the second edge.
As a result of its construction, the expanding device of the present invention provides a number of advantages with respect to the push elements of the prior art, including the following.
The pushing forces are distributed in four substantially symmetrical points, which provides a more balanced expansion of the structure of the display case.
The sliding run carried out by some of the push edges of the expanding device on the inner surfaces of the panels of the structure of the display case during the expansion and collapsing processes of the display case is relatively small, which results in a smooth sliding both upon collapsing and upon expanding the display case. Optionally, the laminar bodies can have marked thereon parallel score lines close to the push edges to cause a slight curvature thereof when they push on the panels of the display case and thus cause a smoothing effect of the sliding.
As a result of the crossed arrangement of the laminar bodies, one and the same expansion volume of the display case can be achieved with relatively short lever arms (between the first and second push edges of the laminar bodies and the fulcrum line), which results in a greater robustness of the expanding device.
According to a second aspect, the present invention provides a self-expandable foldable display case of the type comprising at least one structure formed from at least two panels facing one another and attached at the side edges thereof, and which in a collapsed situation adopt a planar configuration, and in a service position adopt a three-dimensional configuration capable of standing upright, and at least one expanding device arranged between said panels. The self-expandable foldable display case of the present invention is characterized in that said expanding device has the essential features of the expanding device of the first aspect of the present invention described above.
The two or more panels forming the structure of the display case according to an embodiment of the present invention are formed from a single piece of laminar material, in which the panels are arranged in parallel and connected to one another by longitudinal fold lines delimiting the mentioned side edges of the panels, except end side edges of the end panels. From an end side edge of one of said end panels there extends an attachment flange connected to said piece of laminar material by a longitudinal fold line facilitating the bending thereof. This attachment flange is arranged to be attached, for example by means of an adhesive, to the end side edge of the other one of the end panels.
The mentioned piece of laminar material further comprises transverse fold lines perpendicular to said longitudinal fold lines and running through all the panels. When the display case is assembled, these transverse fold lines allow a folding of the structure from the mentioned collapsed situation to a folded situation. Furthermore, to facilitate the folding of the display case and prevent tears in the edges, each of the transverse fold lines is formed by at least three, and preferably at least four, adjacent transverse fold lines, the mentioned attachment flange is interrupted in the areas where the transverse fold lines join the end side edge of the corresponding end panel, and the longitudinal fold lines are aligned with longitudinal cuts in areas of crossing with the transverse fold lines.
With this construction based on a single piece of laminar material, the manufacturing, handling and storage costs of the structure of the display case are significantly lower in comparison with other display cases of the prior art constructed from separate panels attached at the side edges thereof by means of elastic bands hooked in inwardly bent flanges. Furthermore, given that the outer surfaces of the panels of the display case usually have printed graphic information, the display case of the present invention allows printing all the panels by means of a single printing operation of the piece of laminar material instead of a printing operation for each individual panel, as occurs with the display cases of the prior art, which entails a significant saving in the printing and handling costs.
According to an embodiment, the structure of the display case is formed by two panels facing one another and attached at side edges, and in the expanded situation adopts a convex configuration with an elliptical or ogival cross-section, which in an extreme case can even be virtually circular. According to other embodiments, the structure of the display case can be formed by a variable number of panels attached at the side edges thereof, and which in the expanded situation adopt a prismatic planar-face configuration, the cross-section of which is preferably a polygon with an even number of sides, for example a rectangle, a square or a regular or irregular hexagon, where at least two of the panels of a larger size are facing one another. According to another embodiment, the structure of the display case comprises two or more panels, including two opposed panels of a larger size, one of which has a convex arched configuration and the other one is planar when the display case adopts the expanded situation.
With most embodiments of the structure of the display case described above, the expanding device can be attached to at least one of the panels in a position such that said fulcrum line is substantially parallel to the mentioned side edges of the panels. However, it is also possible to attach the expanding device to the structure in a position such that said fulcrum line is substantially perpendicular to the mentioned side edges of the panels. This horizontal arrangement of the fulcrum line is suitable when the structure comprises, for example, two opposed panels, at least one of which has a convex arched configuration, in which case the first and/or second edges of the first and second laminar bodies of the expanding device are curved-convex, whereby they aid in forming and maintaining said convex arched configuration of one or both opposed panels of the structure. When the structure comprises two opposed panels of a larger size, with a planar configuration, it is likewise suitable to arrange the expanding device with the fulcrum line horizontal and with the first and second edges of the first and second laminar bodies rectilinear to aid in maintaining said planar configuration of the two opposed panels of the structure. The horizontal arrangement of the fulcrum line is also suitable when the structure comprises two opposed panels of a larger size, one of which has an convex arched configuration and the other one is planar, in which case the first edges of the first and second laminar bodies of the expanding device are curved-convex according to said convex arched configuration of one of the opposed panels of the display case and the second edges of the first and second laminar bodies of the expanding device are rectilinear according to said planar configuration of the other one of the opposed panels of the structure.
In the case of a display case which in the expanded position has a planar larger face and in which the fulcrum line of the expanding device is arranged in a horizontal position, the attachment flange is formed in one of the mentioned rectilinear edges of one of the laminar bodies of the expanding element. Furthermore, the laminar body involved has a widened area such that said rectilinear edge has a length covering the entire or a substantial part of the width of the planar panel, or of one of the planar panels, of the structure. The attachment flange is attached to the inner surface of this planar panel of the structure. With this arrangement, when the structure of the display case adopts the expanded situation, the attachment flange and the laminar body to which it is connected form a dihedral angle which is a significant reinforcement for maintaining the planar configuration of the planar panel of the display case.
According to another particular embodiment of the display case of the present invention, the display case comprises at least two structures and an additional panel extending from one of said two structures to the other. Each of the two structures includes at least two opposed panels of a larger size, and at least one of the two panels of a larger size is a planar panel in the expanded situation. The mentioned additional panel has a first side edge attached to a side edge of the planar panel of one of said two structures and a second side edge attached to a side edge of the planar panel of the other one of said two structures. Both structures can be arranged with their respective planar panels mutually aligned and in turn aligned with the additional panel in order to jointly form a mural of a large size, suitable, for example, as a support for a digital print of a large size. Obviously, following this example, display cases could be constructed to form murals of a large size starting from a number n of structures and a number n-1 of additional panels, with each additional panel extending between every two of the structures.
Additionally, the display case includes one or more shelves, each of which comprises a foldable ledge panel, a contractible reinforcement member located below the ledge panel, and an elastic element for contracting the reinforcement member in the expanded situation.

Brief Description of the Drawings

The previous and other features and advantages will be more fully understood from the following detailed description of exemplary embodiments with reference to the attached drawings, in which:

Figures 1A and 1B are plan views of first and second laminar bodies, respectively, which form part of an expanding device for a self-expandable foldable display case according to a first embodiment of the first aspect of the present invention;
Figure 2 is a perspective view of the expanding device of the first embodiment formed from the first and second laminar bodies of Figures 1A and 1B assembled and pulled by an elastic band;
Figures 3 and 4 are plan views of the expanding device of the first embodiment applied to a self-expandable foldable display case with an ogival cross-section and to a self-expandable foldable display case with a square cross-section, respectively;
Figures 5A and 5B are plan views of first and second laminar bodies, respectively, which form part of an expanding device for a self-expandable foldable display case according to a second embodiment of the first aspect of the present invention;
Figure 6 is a perspective view of the expanding device of the first embodiment formed from the first and second laminar bodies of Figures 5A and 5B assembled and pulled by an elastic band;
Figure 7 is a plan view of the expanding device of the second embodiment applied to a self-expandable foldable display case comprising two opposed panels with a convex arched configuration determining an ogival cross-section;
Figures 8A and 8B are plan views of first and second laminar bodies, respectively, which form part of an expanding device for a self-expandable foldable display case according to a third embodiment of the first aspect of the present invention;
Figures 9 and 10 are plan and perspective views, respectively, of the expanding device of the third embodiment applied to a self-expandable foldable display case comprising two opposed panels, one of which is has a convex arched configuration and the other one is planar;
Figure 11 is a perspective view of an expanding device formed from first and second laminar bodies assembled and pulled by an elastic band according to a fourth embodiment of the first aspect of the present invention;
Figure 12 is a perspective view of an expanding device according to a variant of the fourth embodiment;
Figure 13 is a plan view of the expanding device corresponding to the variant of the fourth embodiment of Figure 12 applied to a self-expandable foldable display case with a hexagonal cross-section;
Figures 14A and 14B are plan views of first and second laminar bodies, respectively, which form part of an expanding device for a self-expandable foldable display case according to a fifth embodiment of the first aspect of the present invention;
Figure 15 is a perspective view of the fifth embodiment of the expanding device formed from the first and second laminar bodies of Figures 14A and 14B assembled and pulled by an elastic band;
Figure 16 is a plan view of the expanding device of the fifth embodiment of Figure 15 applied to a self-expandable foldable display case with an ogival cross-section;
Figures 17 and 18 are plan and perspective views, respectively, of a variant of the expanding device of the fifth embodiment applied to a self-expandable foldable display case which is cylindrical, i.e., it has a circular cross-section;
Figures 19A and 19B are plan views of first and second laminar bodies, respectively, which form part of an expanding device for a self-expandable foldable display case according to a sixth embodiment of the first aspect of the present invention;
Figure 20 is a perspective view of the expanding device of the sixth embodiment formed from the first and second laminar bodies of Figures 19A and 19B assembled and pulled by an elastic band;
Figure 21 is a plan view of the expanding device of the sixth embodiment applied to a self-expandable foldable display case with an irregular hexagonal cross-section, with two planar panels of a large size facing one another;
Figures 22A and 22B are plan views of first and second laminar bodies, respectively, which form part of an expanding device for a self-expandable foldable display case according to a seventh embodiment of the first aspect of the present invention;
Figure 23 is a perspective view of the expanding device of the seventh embodiment formed from the first and second laminar bodies of Figures 22A and 22B assembled and pulled by an elastic band;
Figures 24A and 24B are plan views of first and second laminar bodies, respectively, which form part of an expanding device for a self-expandable foldable display case according to an eighth embodiment of the first aspect of the present invention;
Figure 25 is a perspective view of the expanding device of the eighth embodiment formed from the first and second laminar bodies of Figures 24A and 24B assembled and pulled by an elastic band;
Figures 26A and 26B are plan views of first and second laminar bodies, respectively, which form part of an expanding device for a self-expandable foldable display case according to a ninth embodiment of the first aspect of the present invention;
Figure 27 is a perspective view of the expanding device of the ninth embodiment formed from the first and second laminar bodies of Figures 26A and 26B assembled and pulled by an elastic band;
Figures 28A and 28B are plan views of first and second laminar bodies, respectively, which form part of an expanding device for a self-expandable foldable display case according to a tenth embodiment of the first aspect of the present invention;
Figure 29 is a plan view of the expanding device of the tenth embodiment formed from the first and second laminar bodies of Figures 28A and 28B assembled and pulled at opposite sides by two elastic bands, applied to a self-expandable foldable display case with an ogival cross-section;
Figure 30 is a plan view of a single piece of laminar material provided with fold lines for the formation of the panels of a self-expandable foldable display case with an ogival cross-section according to a first embodiment of the second aspect of the present invention;
Figure 30A is an enlarged view of detail A of Figure 30;
Figure 30B is an enlarged view of detail B of Figure 30;
Figure 31 is a perspective view of the display case of the first embodiment with indication of details A and B;
Figure 32 is a perspective view showing the display case of the first embodiment in a collapsed and partially folded situation;
Figure 32A is an enlarged view of detail A of Figure 32;
Figure 33 is a perspective view of a self-expandable foldable display case according to a second embodiment of the second aspect of the present invention, including an expanding device providing a support foot;
Figure 34 is a perspective view of the expanding device providing a support foot and forming part of the display case of the second embodiment of Figure 33;
Figure 35 is a perspective view of a self-expandable foldable display case according to a third embodiment of the second aspect of the present invention, configured to provide a mural of a large size;
Figures 36A, 36B and 36C are perspective views showing the display case of the third embodiment in different positions corresponding to different collapsing and folding phases;
Figures 37, 38, 39 and 40 are perspective views showing the construction and the folding functioning of a ledge according to an embodiment adapted to be installed in a self-expandable foldable display case of the present invention;
Figures 41, 42 and 43 are perspective views showing the construction and the folding functioning of a ledge according to another embodiment adapted to be installed in a self-expandable foldable display case of the present invention;
Figures 44A and 44B are plan views of first and second laminar bodies, respectively, which form part of an expanding device for a self-expandable foldable display case according to an eleventh embodiment of the first aspect of the present invention;
Figure 45 is a perspective view of the expanding device of the eleventh embodiment formed from the first and second laminar bodies of Figures 44A and 44B assembled and pulled at opposite sides by elastic bands;
Figure 46 is a plan view of the expanding device of the eleventh embodiment in the expanded position of Figure 45;
Figures 47A and 47B are plan views of first and second laminar bodies, respectively, which form part of an expanding device for a self-expandable foldable display case according to a twelfth embodiment of the first aspect of the present invention;
Figure 48 is a perspective view of the expanding device of the twelfth embodiment formed from the first and second laminar bodies of Figures 47A and 47B assembled and pulled at opposite sides by elastic bands;
Figure 49 is a plan view of the expanding device of the twelfth embodiment in the expanded position of Figure 48 applied to a self-expandable foldable display case with a substantially rectangular cross-section;
Figure 50 is a plan view of the self-expandable foldable display case and of the expanding device of the twelfth embodiment of Figure 49 in an almost collapsed position;
Figure 51 is a plan view of a variant of the expanding device of the twelfth embodiment in the expanded position applied to a self-expandable foldable display case with a substantially rectangular cross-section;
Figure 52 is a plan view of another variant of the expanding device of the twelfth embodiment in the expanded position applied to a self-expandable foldable display case with a substantially rectangular cross-section;
Figures 53 and 54 are perspective views of a self-expandable foldable display case of substantially hexagonal cross-section equipped with an expanding device like that of Figure 52 and provided with an upper board like a table, in open and closed positions, respectively;
Figures 55, 56 and 57 are plan views respectively showing additional embodiments of the expanding device of the present invention in the expanded position, applied to self-expandable foldable display cases with a substantially elliptical cross-section;
Figure 58 is a perspective view of a foldable stiffening element in an expanded position applicable to any of the self-expandable foldable display cases of the present invention provided with at least one planar panel; and
Figures 59 and 60 are profile views of the foldable stiffening element of Figure 58 in expanded and collapsed positions, respectively.

Detailed Description of Exemplary Embodiments

With reference first to Figures 1A, 1B and 2, the expanding device for a self-expandable foldable display case comprises, according to a first embodiment of the first aspect of the present invention, a first laminar body 30, shown separately in Figure 1A, and a second laminar body 40, shown separately in Figure 1B. These first and second laminar bodies 30, 40, are made of a material such as cardboard, corrugated cardboard, plastic, and corrugated plastic, among others. The first laminar body 30 has opposed first and second edges 31, 32 and a stop edge 33 located between said first and second edges 31, 32 and substantially parallel thereto. An insertion portion 34 extends between said stop edge 33 and the second edge 32. The mentioned insertion portion 34 of the first laminar body 30 is located between two portions of said stop edge 33 and comprises retaining configurations 38 adjacent to said portions of the stop edge 33. The second laminar body 40 has opposed first and second edges 41, 42 and a slot 43 located in a mid-area between said first and second edges 41, 42. The mentioned insertion portion 34 of the first laminar body 30 is sized to be inserted in said slot 43 of the second laminar body 40 until said stop edge 33 of the first laminar body 30 makes contact with the second laminar body 40, as shown in Figure 2. In this position, the stop edge 33 and the slot 43 define a fulcrum line along which the first and second laminar bodies 30, 40 can rotate with respect to one another between a planar position (not shown), in which the first and second laminar bodies 30, 40 are superimposed, and an expanded position (Figure 2), in which the first and second laminar bodies 30, 40 are crossed. In the mentioned planar position, the first edge 31 of the first laminar body 30 is substantially adjacent to the first edge 41 of the second laminar body 40 and the second edge 32 of the first laminar body 30 is substantially adjacent to the second edge 42 of the second laminar body 40. The mentioned retaining configurations 38 formed in the base of the insertion portion 34 of the first laminar body 30 contribute to maintaining the insertion portion 34 in position inside the slot 43 of the second laminar body 40.
From the second edge 32 of the first laminar body 30 there extends at least one attachment flange 35 provided to be attached, for example by an adhesive, to an inner face of one of the panels 11, 12 forming a structure 10 of the self-expandable foldable display case, as will be described below. This attachment flange 35 is connected to the corresponding first laminar body 30 by a fold line 35a. It will be understood that, alternatively, the attachment flange 35 could extend from any other of the first and second edges of any of the first and second laminar bodies with an equivalent result, or there could even be more than one attachment flange in one and/or the other of the first and second laminar bodies, as will be seen below.
The first laminar body 30 has a first hooking configuration 36 formed, for example, by die-cutting therein and the second laminar body 40 has a second hooking configuration 46 likewise formed, for example, by die-cutting. As shown in Figure 2, the expanding device of this first embodiment includes a pull element embodied by an elastic band 5 hooked at its ends in said first and second hooking configurations 36, 46, such that the pull element 5 pulls the first and second laminar bodies 30, 40, moving them towards one another towards the expanded position.
In this first embodiment, the second laminar body 40 comprises a limiting appendage 47, formed by die-cutting, capable of making contact with the other one of the first and second laminar bodies 30, 40 to limit the rotation formed by them when they are attracted by the pull element 5 in the expanded position. Thus, the second laminar body 40 has a cut defining both the limiting appendage 47 and the second hooking configuration 46, with the second hooking configuration 46 formed in the limiting appendage 47 close to the base thereof. The limiting appendage 47 has a proximal end connected to the second laminar body 40 by a fold line 47a and a distal edge 47b wider than the first hooking configuration 36 of the first laminar body 30, whereby the elastic band 5 hooked in the first hooking configuration 36 cooperates with said distal edge 47b of the limiting appendage 47 acting as a stop to establish the limit position of the limiting appendage 47 corresponding to the expanded position. In this first embodiment, the fold line 47a connecting the limiting appendage 47 to the second laminar body 40 is located between the slot 43 and the second edges 42 of the second laminar body 40 which is adjacent to the second edge 32, i.e., to the insertion portion 34, of the first laminar body 30 in the planar position, with the fold line 47a adjacent to the slot and the distal edge 47b adjacent to the second edge 42 of the second laminar body 40.
Figure 3 shows the expanding device according to the first embodiment of the present invention applied to a self-expandable foldable display case comprising a structure 10 formed from two panels 11, 12, of a material such as cardboard, corrugated cardboard, plastic, and corrugated plastic, facing one another and attached at the side edges 16, 17 thereof, which in a collapsed situation adopts a planar configuration, and in a service position adopts a three-dimensional configuration capable of standing upright. Furthermore, the panels 11, 12 of the structure 10 of the display case include transverse fold lines 18 (see for example, Figures 30 and 31) perpendicular to the side edges 16, 17 thereof for facilitating the folding of the display case from said collapsed situation to a folded situation (Figure 32). The expanding device is arranged inside the structure 10 of the display case and is capable of adopting its planar position together with the panels 11, 12 in said collapsed situation. When the expanding device adopts the expanded position due to the effect of the pull element 5, the first and second edges 31, 32; 41, 42 of the first and second laminar bodies 30, 40 forming it press the two panels 11, 12 of the structure 10 of the display case from inside such that the display case adopts a three-dimensional configuration with an oval or ogival cross-section. It will be observed that the expanding device is attached to the display case such that the mentioned fulcrum line of the expanding device is arranged in a direction parallel to the side edges 16, 17 of the panels 11, 12 forming the structure 10 of the display case. The display case preferably includes several expanding devices, for example, one for each of the sections into which the transverse fold lines 18 divide the panels 11, 12.
In the first embodiment shown in Figure 2, the expanding device has attachment flanges 35 in the second edges 32, 42 of both the first and second laminar bodies 30, 40 for the attachment to both panels 11, 12 of the structure 10, although a single attachment flange 35 in an edge of only one of the first and second laminar bodies 30, 40 for the attachment to one of the two panels 11, 12 of the structure 10 would be enough. The first and second edges 31, 32; 41, 42 of the first and second laminar bodies 30, 40 of the expanding device which do not have an attachment flange 35 adhered to the panels 11, 12 of the display case slide on the inner faces thereof during the folding and unfolding operations of the structure 10 of the display case.
Figure 4 shows the expanding device according to the first embodiment of the present invention applied to a self-expandable foldable display case comprising a structure 10 formed from four panels, of a material such as cardboard, corrugated cardboard, plastic, and corrugated plastic, attached to one another at the side edges thereof and facing one another two by two, i.e., with two of the panels 11, 12 being mutually facing and the other two of the panels 54, 55 being mutually facing. The display case of Figure 4 can adopt, in a collapsed situation, a planar configuration in which the panels 11, 12 are superimposed on the panels 54, 55, respectively, and, in a service position, a three-dimensional configuration with a substantially square cross-section capable of standing upright. Here, the expanding device is arranged inside the panels 11, 12, 54, 55 of the display case, with the fulcrum line of the expanding device arranged in a direction parallel to the side edges of the panels 11, 12, 54, 55 of the structure 10 of the display case. Thus, each of the first and second edges 31, 32; 41, 42 of the first and second laminar bodies 30, 40 presses from inside one of the four panels 11, 12, 54, 55 of the structure 10 of the display case. There is no drawback here in all the first and second edges 31, 32; 41, 42 of the first and second laminar bodies 30, 40 having attachment flanges 35 adhered to the respective panels 11, 12, 54, 55 of the structure 10 of the display case since there is no relative sliding between them during the folding and unfolding operations.
Figures 5A, 5B, and 6 show a second embodiment of the expanding device, which only differs from the first embodiment in that, in the first laminar body 30, the first hooking configuration 36 is formed in the first edge 31 and, in the second laminar body 40, the fold line 47a connecting the limiting appendage 47 to the second laminar body 40 is adjacent to the second edge 42 thereof and the distal edge 47b of the limiting appendage 47 is between the slot 43 and the first edge 41, such that the limiting appendage 47 crosses the slot 43 and the slot 43 is divided into two portions on both sides of the limiting appendage 47. The limiting appendage 47 can thus be longer and the first and second hooking configurations 36, 46 are more separated from one another and the elastic band 5, which has a greater length, pulls the first and second laminar bodies 30, 40 from areas closer to the respective edges 31, 42 thereof.
Figure 7 shows the expanding device of the second embodiment applied to a self-expandable foldable display case with a structure 10 formed by two panels 11, 12 facing one another and attached at the side edges thereof, the details of the construction of which form part of the present invention and will be explained in greater detail below in relation to Figures 30 and 31. In the application example of Figure 7, the expanding device is placed between the panels 11, 12 of the structure 10 of the display case with the fulcrum line in a vertical position, i.e., parallel to the side edges of the panels 11, 12 of the display case.
In relation to Figures 8A, 8B, 9 and 10, an expanding device is described below according to a third embodiment of the present invention, provided to be installed in a self-expandable foldable display case, the structure 10 of which comprises two opposed panels 11, 12, one of which, in the expanded position, has a convex arched configuration whereas the other one is planar, as shown in Figures 9 and 10. To that end, the expanding device of the third embodiment differs from the second embodiment in that the second edge 32 of the first laminar body 30 and the first edge 41 of the second laminar body 40 are curved-convex according to said convex arched configuration of one of the opposed panels 12 of the display case, and the first edge 31 of the first laminar body 30 and the second edge 42 of the second laminar body 40 are rectilinear according to said planar configuration of the other one of the opposed panels 11 of the structure 10. Furthermore, the attachment flange 35 is formed in the rectilinear edge 42 of the second laminar body 40 of the expanding device. The first rectilinear edge 31 of the first laminar body 30 as well as the second rectilinear edge 42 of the second laminar body 40 and the corresponding attachment flange 35 have an extended length to cover the entire or at least a substantial part of the width of the planar panel 11 of the structure 10, and the attachment flange 35 is attached to the inner surface of said planar panel 11, 12 of the structure 10 in a position such that said fulcrum line of the expanding device is substantially perpendicular to the mentioned side edges of the panels 11, 12. In the expanded situation, the dihedron formed by the second laminar body 40 and the attachment flange 35 is a reinforcement profile which cooperates in maintaining the planar configuration of the panel 11 of the structure 10 of the display case.
Figure 11 shows an expanding device according to a fourth embodiment similar to the third embodiment, but which essentially differs from the latter in that here the second edge 33 of the first laminar body 30 and the first edge 42 of the second laminar body 40 are also rectilinear, which makes the expanding device of the fourth embodiment suitable for a self-expandable foldable display case having two planar panels facing one another. Here also, from the second edge 42 of the second laminar body 40 there extends an attachment flange 35 which, in the operative situation, is attached to the inner surface of said planar panel 11, 12 of the structure 10 in a position such that the fulcrum line of the expanding device is substantially perpendicular to the mentioned side edges of the panels 11, 12.
Figure 12 shows an expanding device according to a variant of the fourth embodiment, which is adapted to be installed in a self-expandable foldable display case with a hexagonal cross-section, as shown in Figure 13. The self-expandable foldable display case with a hexagonal cross-section has a structure 10 formed by six planar panels attached to one another at the side edges thereof and facing one another two by two. Between the panels is installed the expanding device according to this variant of the fourth embodiment, which differs from it only in that the first edge 31 of the first laminar body 30 and the first and second edges 41, 42 of the second laminar body 40 all have one and the same length substantially equal to the width of two of the panels 11, 12 facing one another of the structure 10 of the display case. From the second edge 42 of the second laminar body 40 there extends an attachment flange 35 which, in the operative situation, is attached to the inner surface of one of the planar panels 12 facing one another of the structure 10 in a position such that the fulcrum line of the expanding device is substantially perpendicular to the mentioned side edges of the panels 11, 12. Thus, in the expanded situation shown in Figure 13, the second edge 32 of the first laminar body 30 and the first edge 41 of the second laminar body 40 press against the inner face of one of the panels 11 facing one another of the structure 10 of the display case and the first edge 31 of the first laminar body 30 and the second edge 42 of the second laminar body 40 press against the inner face of the other one of the panels 12 facing one another of the structure 10 of the display case, collaborating in the maintenance of the planar configuration thereof.
Figures 14A, 14B and 15 show an expanding device according to a fifth embodiment which is very similar to the second embodiment, from which it basically differs in that all the opposed edges 31, 32, 41, 42 of the first and second laminar bodies 30, 40 are curved-convex. This is so because, unlike the expanding device of the second embodiment, the expanding device of the fifth embodiment is provided to be installed in a display case formed by a structure 10 with an ogival cross-section but with the fulcrum line of the expanding device arranged in a horizontal position, as shown in Figure 16. To that end, from the second edge 32 of the first laminar body 30 there extends an attachment flange 35 which is attached to an inner face of one of the panels 11, 12 of the structure 10 of the display case. In this case the curved- convex edges 31, 32, 41, 42 of the first and second laminar bodies 30, 40 of the expanding device cooperate in the maintenance of the arched configuration of the panels 11, 12 facing one another of the structure 10 of the display case in the expanded situation.
Figures 17 and 18 show an expanding device according to a variant of the fifth embodiment, especially designed to be installed in a self-expandable foldable display case with an elliptical or circular cross-section. The difference with respect to the expanding device of the fifth embodiment essentially lies in the profile of the curved-convex edges of the first and second laminar bodies 30, 40 adapted to the specific arched configuration of the cylindrical display case. Here, the fulcrum line of the expanding device is arranged in a horizontal position, as shown in Figure 18.
In relation to Figures 19A, 19B and 20, there is now described an expanding device according to a sixth embodiment, provided to be installed in a self-expandable foldable display case provided with a structure 10 with two planar panels 11, 12 facing one another of a large size, such as the display case shown in Figure 21, in which the structure 10 is formed by six panels attached to one another at the side edges thereof, two of which, namely panels 11 and 12, are panels of a large size which in the expanded situation are facing one another and parallel. The expanding device of this sixth embodiment is similar to the second embodiment with the difference that here, the first and second laminar bodies 30, 40 are attached to respective first and second sheets 3, 4 configured to be attached to inner faces of two panels 11, 12 facing one another of the structure 10 of the display case. The first laminar body 30 is thus formed by cut lines in the mentioned first sheet 3 and is connected to the first sheet 3 by a fold line 3a along the first edge 31. Similarly, the second laminar body 40 is formed by cut lines in said second sheet 4 and is connected to the second sheet 4 by a fold line 4a along the first edge 41. When the insertion portion 34 of the first laminar body 30 is inserted in the slot 43 of the second laminar body 40 (Figure 20) and the elastic band 5 is hooked in the corresponding first and second hooking configurations 36, an expanding device is formed which is similar to that of the second embodiment but with the first and second laminar bodies 30, 40 connected to the first and second sheets 3, 4 which, when they are adhered to the planar panels 11, 12 facing one another of the structure 10 of the display case contribute to maintaining the planar configuration thereof. Figure 21 shows the expanding device of the sixth embodiment attached to the display case with the fulcrum line arranged in a vertical position, parallel to the side edges of the panels of the structure 10 of the display case, although this expanding device would also work arranged with the fulcrum line in a horizontal position perpendicular to the side edges of the panels of the structure 10 of the display case.
Figures 22A, 22B and 23 show an expanding device according to a seventh embodiment similar to the second embodiment except in that here the first laminar body 30 (Figure 22A) has a first longitudinal fold line 39 extending from one to the other of the opposed first and second edges 31, 32 thereof, centered with the first hooking configuration 36, and the fold line 35a between the attachment flange 35 and the insertion portion 34 is formed by two fold line portions forming an angle with one another on both sides of said first longitudinal fold line 39. The second laminar body 40 (Figure 22B) has here a second longitudinal fold line 49 extending from one to the other of the opposed first and second edges 41, 42 thereof and along the limiting appendage 47. Furthermore, the slot 43 is formed by two slot portions forming an angle with one another on both sides of said second longitudinal fold line 49, and the fold line 47a in the base of the limiting appendage 47 is formed by two fold line portions forming an angle with one another on both sides of said second longitudinal fold line 49. With this construction, when the insertion portion 34 of the first laminar body 30 is inserted in the slot 43 of the second laminar body 40 and the elastic band 5 is placed in position, the expanding device is capable of adopting a planar position (not shown) with the superimposed first and second laminar bodies 30, 40. However, due to the effect of the pull exerted by the elastic band 5, the expanding device adopts an expanded position in which both the first laminar body 30 and the second laminar body 40, including the limiting appendage 47, are bent through the first and second longitudinal fold lines 39, 49 forming respective dihedrons conferring to the expanding device a significantly increased resistance in the expanded position.
Figures 24A, 24B and 25 show an expanding device according to an eighth embodiment similar to the second embodiment except in that here the second laminar body 40 (Figure 24B) includes side flanges 56 connected to the rest of the second laminar body 40 by respective fold lines 57, and the first laminar body 30 (Figure 24A) includes appendages 58 providing edges forming an angle with the stop edge 33 on both sides of the insertion portion 34. When the first and second laminar bodies 30, 40 are assembled and the elastic band 5 attracts them to the expanded position (Figure 25), the mentioned appendages 58 of the first laminar body 30 force said side flanges 56 of the second laminar body 40 to bend through their respective fold lines 57 to form an angle with respect to the rest of the second laminar body 40, which confers an increased resistance to the second laminar body 40 and, generally, to the entire expanding device.
Figures 26A, 26B and 27 show an expanding device according to a ninth embodiment similar to the previous ones except in that here the first laminar body 30 only has an inclined portion of stop edge 33 on one side of the insertion portion 34, whereas the opposite side has a flange 59 connected to the rest of the first laminar body 30 by a longitudinal fold line 60. In turn, the second laminar body 40 includes, on a side corresponding to the single portion of stop edge 33 of the first laminar body 30, a flange 61 connected to the rest of the second laminar body 40 by a longitudinal fold line 62, and an opening 63 in connection with an end of the slot 63 corresponding to the flange 59 of the first laminar body 30, where said opening 63 defines an inclined edge. When the first and second laminar bodies 30, 40 are assembled and the elastic band 5 attracts them to the expanded position (Figure 27), the inclined portion of stop edge 33 of the first laminar body 30 forces the flange 61 of the second laminar body 40 to bend along the corresponding fold line 62 and the mentioned inclined edge of the opening 63 of the second laminar body 40 forces the flange 59 of the first laminar body 30 to bend along the corresponding fold line 60, such that both first and second laminar bodies 30, 40 form respective dihedrons conferring to the expanding device a significantly increased resistance.
Figures 28A, 28B and 29 show an expanding device according to a tenth embodiment similar to the second embodiment except in that here the first laminar body 30 (Figure 28A) includes an additional first hooking configuration 64 in an end opposite to the first hooking configuration 36 and the second laminar body 40 (Figure 28B) includes an additional second hooking configuration 65 in an end opposite to the second hooking configuration 46, which allows, once the first and second laminar bodies 30, 40 are assembled (Figure 29), installing a second elastic band 66 hooked at its ends to the additional first and second hooking configurations 64, 65 in addition to the first elastic band 5 hooked at its ends to the first and second hooking configurations 36, 46, such that the first and second elastic bands 5, 66 are arranged at opposite sides of the expanding device pulling the opposite ends of the first and second laminar bodies 30, 40. With this construction, the forces exerted by the elastic bands 5, 66 are more distributed and better balanced, which reduces the risk of unwanted bends occurring in the first and second laminar bodies 30, 40.
Figure 29 shows the expanding device of the tenth embodiment installed between the two panels 11, 12 of a structure 10 of a self-expandable foldable display case with an ogival cross-section, where the expanding device is fixed such that the fulcrum line thereof is in a vertical direction parallel to the side edges of the structure 10 of the display case. Nevertheless, a person skilled in the art will understand that the incorporation of two elastic bands 5, 66 can be generalized for any of the expanding devices of the previous embodiments, including those configured to be installed with the fulcrum line in a horizontal position perpendicular to the side edges of the panels of the structure 10 of the display case.
In relation to Figures 30, 31 and 32, a self-expandable foldable display case according to a first basic embodiment of the second aspect of the present invention is described below. The display case comprises a structure 10 formed from a piece of laminar material 20, of a material such as cardboard, corrugated cardboard, plastic, or corrugated plastic, among others, which includes, in the basic version, a longitudinal fold line 17 delimiting adjacent side edges of two panels 11, 12. From a side edge of one of the panels 12 there extends an attachment flange 16 connected to said piece of laminar material 20 by a longitudinal fold line 16a and arranged to be attached to the end side edge of the other one of the panels, such that the structure 10 (Figure 31) comprises two panels 11, 12 facing one another and attached at the opposed side edges 16a, 17 7 thereof. Between the two panels 11, 12 of the display case there is placed an expanding device of the type described above attached to the inner face of one or both panels by one or two of the attachment flanges 35 thereof, as has been explained above. The pulling force of the elastic band 5 of the expanding device causes the expansion of the expanding device such that the first and second laminar bodies 30, 40 thereof push from inside the panels 11, 12 of the structure 10 of the display case to automatically expand the display case from a collapsed situation, in which the panels 11, 12 are superimposed adopting a planar configuration, to a service position or expanded situation, shown in Figure 31, in which the panels 11, 12 adopt a three-dimensional configuration with an ogival cross-section capable of standing upright. A folding of the expanding device against the force of the elastic band 5 and the adoption of the collapsed situation of the display case are achieved by pressing the panels 11, 12 towards one another from outside.
The piece of laminar material 20 further comprises transverse fold lines 18 perpendicular to said longitudinal fold line 17 through the two panels 11, 12, and the attachment flange 16 has interruptions in the areas corresponding to the ends of the transverse fold lines 18, where the transverse fold lines 18 join the side edge 16a of the corresponding panel 12, as shown in the enlarged detail of Figure 30A. These transverse fold lines 18 divide the panels 11, 12 into several sections, and preferably, between every two facing sections of the panels 11, 12 there is installed an expanding device. The transverse fold lines 18 allow a folding of the structure 10 from the collapsed situation to a folded situation, as shown in Figure 32, in which the different sections of the panels 11, 12, being in a planar configuration, are superimposed achieving a compact configuration for the display case, suitable for storage and transport thereof. From the mentioned folded situation of the display case, by simply pulling upwards the upper edge of one of the two panels 11, 12, the force of the elastic bands 5 causes the expansion of the expanding devices and the automatic self-expansion of the display case to the service position shown in Figure 31.
Each of the transverse fold lines 18 is formed by at least three, and preferably four, adjacent transverse fold lines, as can be seen from the enlarged details of Figures 30A, 30B and 32A. Furthermore, the longitudinal fold lines 17 are aligned with longitudinal cuts 19 in areas of crossing with the transverse fold lines 18, as can be seen from the enlarged detail of Figure 30B. The purpose of the several transverse fold lines 18 and the mentioned longitudinal cuts 19 is to facilitate the bending of the panels 11, 12 along the transverse fold lines 18 without unwanted tears occurring in the ends, as shown in the enlarged detail of Figure 32A. The features of the structure 10 of the self-expandable foldable display case described in relation to Figures 30, 31 and 32 allow the structure 10 to be constructed from a single piece of laminar material attached at the end side edges thereof, for example with an adhesive, or from several pieces of laminar material attached at the side edges thereof with an adhesive, without needing elastic attachments using elastic bands, such as with the self-expandable foldable display cases of the prior art. Thus, separate elements and handling and assembly tasks are saved, whereby the self-expandable foldable display case of the present invention is more cost-effective in comparison with those of the prior art.
It must be emphasized that the features described in relation to Figures 30, 31 and 32 can be generalized for self-expandable foldable display cases with a larger number of panels, such as, for example, those shown in Figures 4, 6 and 21 (with a square, regular hexagonal and irregular hexagonal cross-section, respectively) among others, by simply sizing the piece of laminar material 20 suitably and adding a required number of longitudinal fold lines 17. Generally, without it being essential, it is preferred that the structure 10 of the display case has two opposed panels 11, 12 against the inner faces of which the first and second laminar bodies 30, 40 of the expanding devices press, and these opposed panels 11, 12 can be both planar, both convex arched, or one planar and the other one convex arched, as has been explained above.
Figure 33 shows a self-expandable foldable display case comprising a structure 10 with two panels 11, 12 facing one another and attached at the side edges thereof, of the type described above in relation to Figures 30 and 31. In the embodiment of Figure 33, the panels 11, 12 of the structure 10 only have a transverse fold line 18 each, such that they are divided into two superimposed sections, and in each section there is arranged an expanding device according to the fifth embodiment of the first aspect of the present invention described above in relation to Figures 14A, 14B and 15. The difference is that here the second laminar body 40 of the expanding device comprises at least one extension portion 37 extending from its second edges 42 and one of the panels 11 of the structure 10 of the display case has formed therein a slot 67 close to a lower end adjacent to the base thereof. In the expanded situation, said extension portion 37 of the expanding device is passed through the mentioned slot 67 of the panel 11 of the structure 10 to make contact with the floor. The extension portion 37 of the expanding device thus acts as a support foot contributing to hold the expanded display case in the upright position.
It will be understood that, alternatively, the extension portion 37 could extend from the first edge 41 of the second laminar body 40 and/or from any of the opposed first and second edges 31, 32 of the first laminar body 30, and the slot 67 could be formed in the second panel 12 or there could be two slots 67, one in each panel 11, 12, for two extension portions 37 extending from both first and second laminar bodies 30, 40.
In relation to Figures 35, 36A, 36B and 36C, a self-expandable foldable display case according to another embodiment of the second aspect of the present invention is described below. The display case of Figure 35 comprises two structures 10a, 10b, each of which is essentially constructed according to the embodiment described above in relation to Figures 30, 31 and 32. Thus, each of the structures 10a, 106 comprises two opposed panels 11a, 12a; 11b, 12b, and other two narrower panels therebetween. In the expanded situation, one of the opposed panels 11a, 11b of each structure 10a, 10b is a planar panel, and the other one of the opposed panels 12a, 12b is a convex arched panel. The two structures 10a, 10b are separated and the display case includes an additional panel 15 extending from one to the other, covering the separation space between both. This additional panel 15 has a first side edge 15a attached to a side edge of the planar panel 10a of one of said two structures 10a and a second side edge 15b attached to a side edge of the planar panel 11b of the other one of said two structures 10b. The two structures 10a, 10b are configured to be arranged in a service position in which their planar panels 11a, 11b are aligned with the additional panel 15 to jointly form a mural of large dimensions.
Figures 36A, 36B and 36C show a sequence of positions corresponding to different phases in a folding operation of the display case. Preferably, the width of the additional panel 15 is approximately equal to the widths of the opposed panels 11a, 11b; 12a, 12b of the structures 10a, 10b, such that the display case, from a collapsed situation, can be folded along the side edges 15a, 15b of the additional panel 15 to superimpose the different panels in a planar configuration. Furthermore, both the panels 11a, 11b; 12a, 12b of the structures 10a, 10b and the additional panel 15 of the display case comprise mutually aligned transverse fold lines 18 which divide the display case into different superimposed sections and which allow folding the display case along the transverse fold lines 18 to arrange the several superimposed sections in a planar and compact configuration suitable for the storage and transport of the display case.
Figures 37, 38, 39 and 40 show a shelf designed to be installed in the structure 10 of any one of the display cases of the present invention. The shelf comprises a ledge panel 50 made of a laminar material, such as cardboard, corrugated cardboard, plastic, or corrugated plastic, among others, comprising a transverse fold line 50a defining a rear edge 50a and an attachment flange 68, by means of which the ledge panel 50 is attached in an articulated manner by said rear edge 50a to the inner face of one of the opposed panels, for example, the first panel 11 (schematically depicted in Figure 38) of the structure 10 of the display case. A front part of the ledge panel 50 is passed through an opening 51 formed in the other panel 12 (schematically depicted by means of dotted lines in Figure 38) of the structure 10. The ledge panel 50 can thus adopt a position substantially parallel to and superimposed on the panels 11, 12 of the structure 10 in the collapsed situation and a position substantially perpendicular to the panels 11, 12 of the structure 10 in the expanded situation. Below the ledge panel 50 there is arranged a reinforcement member 52 made of a laminar material, such as cardboard, corrugated cardboard, plastic, or corrugated plastic, among others. This reinforcement member has several fold lines 52b substantially perpendicular to said rear edge 50a of the ledge panel 50. Two of said fold lines 52b define an attachment area 52a in a central area of the reinforcement member 52, which is attached to a lower face of said ledge panel 50, such that the reinforcement member 52 can adopt a planar position superimposed on the ledge panel 50 in the collapsed situation or a three-dimensional position bent in zigzag in the expanded situation. An elastic element, such as an elastic band 53, is arranged to contract said reinforcement member 52, bending it in zigzag through said fold lines 52b when the structure 10 of the display case passes from the collapsed situation to the expanded situation. Thus, the zigzag bends form dihedrons conferring a greater bending strength to the reinforcement member 52 which, furthermore, in the service position of the display case, is supported at its front part on an edge of the mentioned opening 51 of the panel 12 of the structure 10 of the display case, and the ledge panel 50 rests on the reinforcement member 52.
Figures 41, 42 and 43 show a shelf according to a variant of the shelf described above in relation to Figures 37, 38, 39 and 40, adapted in this case to a display case provided with a structure 10 with an ogival cross-section. To that end, the reinforcement member 52, shown separately in Figure 41, includes a slightly curved transverse fold line 69 defining an attachment flange 70, and several longitudinal fold lines 71 substantially perpendicular to said transverse fold line 69. Two of said longitudinal fold lines 71 are located in the central part of the reinforcement member 52, defining between them an attachment area 72, and the remaining longitudinal fold lines 71 are connected to transverse fold line 69 by respective bifurcations. The reinforcement member 52 is attached in an articulated manner to the inner face of one of the opposed panels, for example, the first panel 11 (schematically depicted in Figure 38) of the structure 10 of the display case by the attachment flange 70, such that when the structure 10 of the display case is in the collapsed situation, the reinforcement member 52 is in a vertical planar position (Figure 41).
When the structure 10 of the display case adopts the expanded situation, the reinforcement member 52 is bent through the transverse fold line 69 and, in accordance with the curvature acquired by the first panel 11 of the structure 10 of the display case, the reinforcement member is arranged in a horizontal position with a three-dimensional configuration bent in zigzag through the longitudinal fold lines 71 (Figure 42). In the expanded situation, a front part of the reinforcement member 52 rests on an edge of an opening 51 formed in the other panel 12 (schematically depicted by means of dotted lines in Figures 42 and 43) of the structure 10. Here, the ledge panel 50 is a simple planar panel, more or less rigid, adhered at the upper part to the mentioned attachment area 72 of the reinforcement member 52, and which accompanies the reinforcement member 52 in the movements between the collapsed and expanded positions.
Figures 44A, 44B, 45 and 46 show an expanding device according to an eleventh embodiment similar to the tenth embodiment described above, but with the different that here, in addition to the first limiting appendage 47 formed in the second laminar body 40, the first laminar body 30 (Figure 44A) includes a second limiting appendage 73. The first limiting appendage 47 is connected to the second laminar body 40 by a fold line 47a adjacent to the first edge 41 and the distal edge 47b of the first limiting appendage 47 is located between the slot 43 and the second edge 42. The second limiting appendage 73 is connected to the first laminar body 30 by a fold line 73a adjacent to the first edge 31 and the distal edge 73b of the second limiting appendage 73 is located between the stop edge 33 and the second edge 32. The first hooking configuration 36 is formed in the base of the second limiting appendage 73 of the first laminar body 30 and the second hooking configuration 46 is formed in the second edge 42 of the second laminar body 40, whereas an additional first hooking configuration 64 is formed in the second edge 32 of the first laminar body 30 and an additional second hooking configuration 65 is formed in the base of the first limiting appendage 47 of the second laminar body 40. From the first edge 31 of the first laminar body 30 there extends an attachment flange 35 connected to the corresponding first laminar body 30 by a fold line 35a. This flange is provided to be attached, for example by an adhesive, to an inner face of one of the panels forming a structure of the self-expandable foldable display case. It will be understood that, alternatively, the attachment flange 35 could extend from the first edge 41 of the second laminar body 40 with an equivalent result, or there could even be attachment flanges in both the first and second laminar bodies.
As shown in Figures 45 and 46, the first and second laminar bodies 30, 40 of the eleventh embodiment, once assembled with the insertion portion 34 of the first laminar body 30 inserted in the slot 43 of the second laminar body 40, are pulled towards one another and towards an expanded position on one side by an elastic band 5 hooked at its ends in the first and second hooking configurations 36, 46, and on the opposite side by a second elastic band 66 hooked at its ends to the additional first and second hooking configurations 64, 65, whereas the distal edges 47b, 73b of the first and second limiting appendages 47, 73 make contact with the first and second laminar bodies 30, 40, respectively, to limit the rotation and stabilize the expanding device in the expanded position. The expanding device thus includes first and second elastic bands 5, 66 and first and second limiting appendages 47, 73 at opposite sides of the fulcrum line.
In relation to Figures 47A, 47B and 48, a twelfth embodiment of the expanding device of the present invention is described below, which is formed from first and second laminar bodies 30, 40 shown separately in Figures 47A and 47B, respectively. The first laminar body 30 has parallel opposed first and second edges 31, 32. From the first edge 31 there extends an attachment flange 35 connected to the first laminar body 30 by a fold line 35a. This attachment flange 35 is provided to be attached, for example, by an adhesive, to an inner face of one of the panels forming a structure of the self-expandable foldable display case (Figure 49). In the second edge 32 there is formed a first hooking configuration 36. The first laminar body 30 includes an intermediate first fold line 74 arranged between the first and second edge 31, 32 and parallel thereto. The first laminar body 30 has a first insertion portion 34 extending between the second edge 32 and a first stop edge 33 parallel thereto, and a second insertion portion 76 extending between the first edge 31 and a second stop edge 77 parallel thereto. Additional first hooking configurations 78 are formed in the ends of the intermediate first fold line 74 adjacent to the side edges of the first laminar body 30.
The second laminar body 40 shown in Figure 47B has parallel opposed first and second edge 41, 42, and an intermediate second fold line 75 arranged between the first and second edge 41, 42 and parallel thereto. Between said intermediate second fold line 75 and the second edge 42 there is a first slot 43 parallel thereto and between the intermediate second fold line 75 and the first edge 41 there is a second slot 80 parallel thereto. The first slot 43 is crossed by a limiting appendage 47 formed by die-cutting, which is connected to the second laminar body 40 by a fold line 47a adjacent to the second edge 42. The limiting appendage 47 has a distal edge 47b located between the slot 43 and the intermediate second fold line 75, and a second hooking configuration 46 is formed in the base of the limiting appendage 47. Additional second hooking configurations 79 are formed in the ends of the intermediate second fold line 75 adjacent to the side edges of the second laminar body 40.
In the operative situation shown in Figure 48, the first and second laminar bodies 30, 40 are bent through their respective intermediate first and second fold lines 74, 75 and assembled with the first and second insertion portions 34, 76 of the first laminar body 30 inserted respectively in the first and second slots 43, 80 of the second laminar body 40, such that the first and second stop edges 33, 77 of the first laminar body 30 establish respective first and second fulcrum lines in contact with the second laminar body 40. The first and second laminar bodies 30, 40 of the twelfth embodiment are pulled towards one another and towards an expanded position on one side by an elastic band 5 hooked at its ends in the respective first and second hooking configurations 36, 46, and on the opposite side by a second elastic band 66 hooked at its ends to the additional first and second hooking configurations 78, 79, whereas the distal edge 47b of the limiting appendage 47 makes contact with the first laminar body 30 for the purpose of limiting the rotation and stabilizing the expanding device in the expanded position. It is not essential for the additional first and second hooking configurations 78, 79 to be in the respective intermediate first and second fold lines 74, 75, although it is preferable for them to be close to such fold lines.
Figures 49 and 50 show the expanding device of the twelfth embodiment described in relation to Figures 47A, 47B and 48 applied to a self-expandable foldable display case with a substantially rectangular cross-section. The self-expandable foldable display case of Figures 49 and 50 comprises a structure 10 formed by a pair of mutually facing first panels 11, 12, connected by the side edges thereof by a pair of mutually facing second panels 81, 82, each of which is divided by a respective middle fold line 83, 84. The mentioned first and second panels 11, 12, 81, 82 are of a laminar material, such as, for example, cardboard, corrugated cardboard, plastic, or corrugated plastic, among others. The attachment flange 35 of the first laminar body 30 is attached, for example, by an adhesive, to an inner face of one of the first panels 11, 12 facing one another of the structure 10 of the self-expandable foldable display case, such that when, as a consequence of the tension of the elastic bands 5, 66, the expanding device adopts the expanded position (Figure 49), the first edges 31, 41 of the first and second laminar bodies 30, 40 press against the inner face of one of the first panels 11, 12 and the second edges 32, 42 of the first and second laminar bodies 30, 40 press against the inner face of the other one of the first panels 11, 12, and thus maintain the first panels 11, 12 separated and the second panels 81, 82 substantially tense and planar. To fold the structure 10 of the self-expandable foldable display case, an external pressure must be exerted on the first panels 11, 12 to overcome the tension of the elastic bands 5, 66, as shown in Figure 50, such that the first panels 11, 12 move mutually closer and the second panels 81, 82 are bent through their respective middle fold lines 83, 84 such that their halves tend to be aligned with the first panels 11, 12. It will be understood that, although Figures 49 and 50 show the second panels 81, 82 being bent with the middle fold lines 83, 84 outwards, alternatively the second panels 81, 82 could be bent with the middle fold lines 83, 84 inwards in order to adopt an even more compact collapsed position.
The advantage of the expanding device of the twelfth embodiment with two areas of crossing, i.e., with two fulcrum lines, is that it requires a relatively small space when it is in the collapsed position and can acquire, however, a large volume in the expanded position, since it behaves similarly to a pantograph. One or more ways to introduce additional fulcrum lines to increase the points of crossing between the first and second laminar bodies 30, 40 can easily occur to a person skilled in the art without departing from the scope of the present invention.
Figure 51 shows a structure 10 of a self-expandable foldable display case with a substantially rectangular cross-section similar to that shown in Figures 49 and 50, but with an expanding device according to a first variant of the twelfth embodiment described in relation to Figures 47A, 47B and 48. The main difference is that the lengths of the first and second laminar bodies 30, 40 from the first fulcrum line 33 to their respective second edges 32, 42, from the first fulcrum line 33 to their respective intermediate first and second fold lines 74, 75, from the second fulcrum line 77 to their respective first edges 31, 41, and from the second fulcrum line 77 to their respective intermediate second fold lines 74, 75 are substantially equal.
Figure 52 shows a structure 10 of a self-expandable foldable display case with a substantially rectangular cross-section similar to that shown in Figures 49 and 50, but with an expanding device according to a second variant of the twelfth embodiment described in relation to Figures 47A, 47B and 48. Here, the lengths of the first and second laminar bodies 30, 40 from the first fulcrum line 33 to their respective second edges 32, 42 and from the second fulcrum line 77 to their respective first edges 31, 41 are significantly greater than the distances from the respective intermediate first and second fold lines 74, 75 to the first and second fulcrum lines 33, 77. Furthermore, in this second variant, the first laminar body 30 incorporates a second limiting appendage 85 associated with an additional pull element or elastic band 86 similar to the first limiting appendage 47 and associated first elastic band 5.
Figures 53 and 54 show a self-expandable foldable display case with a substantially hexagonal cross-section equipped with an expanding device such as the one described above in relation to Figure 52 and provided with an upper board 87 lowerable between an open position (Figure 53), in which the upper board 87 is coplanar with the panel 11 to which it is attached, and a closed position (Figure 54), in which said upper board 87 is supported on the upper edges of one or more of the remaining panels 12, 81, 82 and can act like a table or any other type of support surface. Firstly, it must be indicated that the structure 10 of the self-expandable foldable display case with a substantially hexagonal cross-section shown in Figures 53 and 54 and the structure 10 of the self-expandable foldable display case with a substantially rectangular cross-section shown in Figures 49 to 52 are virtually identical, and it is the configuration of the limiting appendage or appendages 47, 85 which determines the degree of expansion of the expanding device, and therefore the rectangular or hexagonal configuration of the structure 10 in the expanded position. Optionally, all the panels 11, 12, 81, 82 of the structure 10 of the display cases shown in Figures 49 to 54 can have transverse fold lines (similar, for example, to those shown in Figures 30 and 31) to allow folding the display case from the collapsed situation to a folded situation.
The upper board 87 is connected to the upper edge of one of the mutually facing first panels 11, 12 of the structure 10 by means of a hinge element 88 consisting of an elongated strip of laminar material, such as, for example, cardboard, corrugated cardboard, plastic, or corrugated plastic, provided with a longitudinal middle fold line 89 dividing said hinge element 88 into two halves. One of said halves of the hinge element 88 is attached, for example, by an adhesive, to the corresponding first panel 11 and the other half is attached to the upper board 87, such that the upper board 87 is maintained attached to the structure 10 by the hinge element 88 and at the same time can rotate between the open and closed positions around the middle fold line 89 of the hinge element 88. Obviously, the hinge element 88 described in relation to Figures 53 and 54 can be applicable to attach any board to any panel of a structure 10 of a self-expandable foldable display case according to any embodiment of the present invention, or of any other display case, with the condition that at least the portion of the panel of the structure 10 where the hinge element 88 is attached is planar, and taking into account that the board 87 in the open position does not interfere in the folding and expansion operations of the structure 10. It will be likewise understood that providing the board 87 and the hinge element 88 is compatible with any of the embodiments of the expanding device of the present invention.
In relation to Figures 55 to 57, some additional variations on the expanding device and the self-expandable foldable display case of the present invention are described below, where the expanding device comprises, for example, two first laminar bodies 30 coupled to a single second laminar body 40. Each of the first laminar bodies 30 comprises (in a manner similar to that described above in relation to any previous embodiment) opposed first and second edges 31, 32 and a respective insertion portion 34 between a stop edge 33 and the second edge 31, whereas the second laminar body 40 has opposed first and second edges 41, 42 and two slots 43 formed between said opposed first and second edges 41, 42 and parallel thereto. The first laminar bodies 30 include respective first hooking configurations and the second laminar body 40 includes a pair of second hooking configurations for corresponding elastic bands 5. In the operative situation, the insertion portions 34 of the two first laminar bodies 30 are inserted in the slots 43 of the second laminar body 40 such that the stop edges 33 provide respective fulcrum lines for the rotation of the two first laminar bodies 30 with respect to the second laminar body 40. Either the first laminar bodies 30 or the second laminar body 40 have formed therein at least one limiting appendage 47 to limit the rotation of each first laminar body 30 in a manner similar to that described above.
The self-expandable foldable display case of Figure 55 is of the type formed by two panels 11, 12 attached at the side edges thereof and capable of adopting an outward convex position, similar to that described above, for example, in relation to Figures 30 and 31, and it is associated with an expanding device, the two first laminar bodies 30 of which are arranged such that their respective insertion portions 34 are at opposite sides of the second laminar body 40.
The self-expandable foldable display case of Figure 56 is also of the type formed by two panels 11, 12 capable of adopting an outward convex position, similar to that described above in relation to Figures 30 and 31, and it is associated with an expanding device having the insertion portions 34 of the two first laminar bodies 30 arranged at the same side of the second laminar body 40 and the limiting appendages 47 at the same side of the first laminar bodies 30.
The self-expandable foldable display case of Figure 57 is likewise of the type formed by two panels 11, 12 capable of adopting an outward convex position, similar to that described above in relation to Figures 30 and 31, and it is associated with an expanding device having the insertion portions 34 of the two first laminar bodies 30 arranged at the same side of the second laminar body 40 and the limiting appendages 47 at opposite sides of the first laminar bodies 30. The symmetrical arrangement of the two first laminar bodies 30 enables the second edges 32 thereof to cooperate with vertical fold lines 90 formed in one of the panels 11 of the structure 10 of the display case to provide a planar portion 11c in the panel 11 even when the display case is in the expanded position, and this planar portion 11c of the panel 11 of the display case can be useful, for example, for the attachment of the corresponding half of a hinge element 88 similar to the one described above in relation to Figures 53 and 54 for the purpose of incorporating an upper board 87 to the structure 10 of the self-expandable foldable display case.
Figure 58 shows a foldable reinforcement member 91, made of a laminar material, such as, for example, cardboard, corrugated cardboard, plastic, or corrugated plastic, among others, which is attached to a foldable panel 92 which can form part of a structure 10 according to any one of the embodiments of the self-expandable foldable display case of the present invention provided with at least one planar panel or with a panel with a planar portion. The foldable reinforcement member 91 has mutually parallel opposed first and second edges 95a, 95b and several fold lines parallel to said opposed first and second edges 95a, 95b which determine a central attachment area 96 flanked by a pair of foldable portions 97a, 97b, each divided into two by one of said fold lines 101. At least one pull element, such as an elastic band 98, is secured by its ends in first and second hooking configurations 99a, 99b of the foldable reinforcement member 91, located adjacent to the opposed first and second edges 95a, 95b, and passed through windows 100 formed in the foldable portions 97a, 97b. The foldable reinforcement member 91 has a transverse fold line 93 perpendicular to the several fold lines, which traverses it from the first to the second opposed edges 95a, 95b, and the foldable panel 92 likewise has a transverse fold line 94 traversing it completely.
In an operative situation, the attachment area 96 is attached, for example, by an adhesive, to the mentioned foldable panel 92 (Figure 58) such that the transverse fold line 93 of the foldable reinforcement member 91 coincides, i.e., it is superimposed on the transverse fold line 94 of the foldable panel 92. The tension of said elastic band 98 pulls the first and second edges 95a, 95b of the foldable reinforcement member 91 towards one another, such that the foldable reinforcement member 91 adopts a three-dimensional position (shown in Figures 58 and 59) in which the foldable portions 97a, 97b are bent through their central fold lines 101, forming rigid crests preventing the assembly from being bent through the superimposed transverse fold lines 93, 94 of the foldable reinforcement member 91 and of the foldable panel 92, respectively. In this position, for example, a part of the foldable panel 92 above the transverse fold line 94 would remain upright or the entire foldable panel 92 would remain rigid, supported by the expanded foldable reinforcement member 91. To bend the foldable panel 92 it is necessary to first press the crests formed by the foldable portions 97a, 97b of the foldable reinforcement member 91 until overcoming the tension of the elastic band 98 to arrange the foldable reinforcement member 91 in a substantially planar collapsed position (Figure 60), in which the foldable reinforcement member 91 offers virtually no resistance to the bending of the assembly through the superimposed transverse fold lines 93, 94.
Optionally, the foldable reinforcement member 91 can incorporate limiting appendages 102 (Figure 59), similar to the limiting appendage 47 described above in relation to the embodiments of the expanding device, to limit the degree of folding of the foldable portions 97a, 97b in the expanded position.
A person skilled in the art will be able to carry out modifications and variations from the embodiments shown and described without departing from the scope of the present invention as it is defined in the attached claims.

Claims

An expanding device for a self-expandable foldable display case, said self-expandable foldable display case being of the type comprising a structure (10) formed from at least two panels (11, 12) facing one another and attached at the side edges thereof, and which in a collapsed situation adopts a planar configuration, and in a service position adopts a three-dimensional configuration capable of standing upright, and said expanding device being of the type comprising at least one laminar body attached to at least one of said panels (11, 12), said laminar body being capable of adopting a planar position together with the panels (11, 12) in said collapsed situation, and a pull element arranged to rotate, curve or bend the laminar body between the panels (11, 12) and thus cause the expansion of said structure (10) of the display case, characterized in that it comprises:
a first laminar body (30) having opposed first and second edges (31, 32) and at least one insertion portion (34) extending between at least one stop edge (33) located between said first and second edges (31, 32) and one of said first and second edges (31, 32); and

a second laminar body (40) having opposed first and second edges (41, 42) and at least one slot (43) located in an area between said first and second edges (41, 42);

wherein said insertion portion (34) of the first laminar body (30) is sized to be inserted in said slot (43) of the second laminar body (40) until said stop edge (33) of the first laminar body (30) makes contact with the second laminar body (40); and

wherein the stop edge (33) and the slot (43) define a fulcrum line along which the first and second laminar bodies (30, 40) can rotate with respect to one another between a planar position, in which the first and second laminar bodies (30, 40) are superimposed, and an expanded position, in which the first and second laminar bodies (30, 40) are crossed.
The device according to claim 1, characterized in that from at least one of the first and second edges (31, 32; 41, 42) of the first and second laminar bodies (30, 40) there extends at least one attachment flange (35) for the attachment to an inner face of one of the panels (11, 12) of the structure (10), wherein said attachment flange (35) is connected to the corresponding first or second laminar body (30, 40) by a fold line (35a).
The device according to claim 1 or 2, characterized in that the first laminar body (30) has a first hooking configuration (36) and the second laminar body (40) has a second hooking configuration (46), and said pull element comprises an elastic band (5) hooked at its ends in said first and second hooking configurations (36, 46) to pull the first and second laminar bodies (30, 40) towards the expanded position.
The device according to claim 3, characterized in that at least one of the first and second laminar bodies (30, 40) comprises a limiting appendage (47) capable of making contact with the other one of the first and second laminar bodies (30, 40) to limit the rotation in the expanded position.
The device according to claim 4, characterized in that the second laminar body (40) has a cut defining said limiting appendage (47) and the second hooking configuration (46) in the limiting appendage (47), wherein a proximal end of the limiting appendage (47) is connected to the first laminar body by a fold line (47a).
The device according to claim 5, characterized in that the limiting appendage (47) has a distal edge (47b) wider than said first hooking configuration (36) of the first laminar body (30), and said elastic band (5) cooperates with said distal edge (47b) of the limiting appendage (47) to establish the limit position of the limiting appendage (47) corresponding to the expanded position.
The device according to claim 5 or 6, characterized in that said fold line (47a) connecting the limiting appendage (47) to the second laminar body (40) is located between the slot (43) and that one of the first and second edges (41, 42) of the second laminar body (40) which is adjacent to the insertion portion (34) of the first laminar body (30) in the planar position.
The device according to claim 7, characterized in that the limiting appendage (47) crosses the slot (43) and the slot (43) is divided into two portions on both sides of the limiting appendage (47).
The device according to any one of the previous claims, characterized in that the second laminar body (40) has a second longitudinal fold line (49) extending from one to the other of the opposed first and second edges (41, 42) thereof and along the limiting appendage (47), said slot (43) is formed by two slot portions forming an angle with one another on both sides of said second longitudinal fold line (49) and said fold line (47a) of the second laminar body (40) is formed by two fold line portions forming an angle with one another on both sides of said second longitudinal fold line (49), and the first laminar body (30) has a first longitudinal fold line (39) extending from one to the other of the opposed first and second edges (31, 32) thereof, centered with the first hooking configuration (36), and said fold line (35a) of the first laminar body (30) is formed by two fold line portions forming an angle with one another on both sides of said first longitudinal fold line (39).
The device according to any one of claims 1 to 8, characterized in that the first laminar body (30) is formed by cut lines in a first sheet (3) and is connected to said first sheet (3) by a fold line (3a) along one of the opposed first and second edges (31, 32) of the first laminar body (30), and the second laminar body (40) is formed by cut lines in a second sheet (4) and is connected to said second sheet (4) by a fold line (4a) along one of the opposed first and second edges (41, 42) of the second laminar body (40), said first and second sheets (3, 4) being configured to be attached to inner faces of two panels (11, 12) facing one another of said structure (10).
The device according to any one of claims 1 to 8, characterized in that at least one of the first and second edges (31, 32; 41, 42) of each of the first and second laminar bodies (30, 40) of the expanding device is a curved-convex edge.
The device according to any one of the previous claims, characterized in that the insertion portion (34) of the first laminar body (30) is located between two portions of said stop edge (33) and comprises retaining configurations (38) adjacent to said portions of the stop edge (33).
The device according to claim 4, characterized in that the first and second laminar bodies (30, 40) comprise respective additional first and second hooking configurations (64, 65) and a second pull element in the form of a second elastic band (66) is hooked at its ends in said additional first and second hooking configurations (64, 65) to pull the first and second laminar bodies (30, 40) towards the expanded position, said first and second elastic bands (5, 66) being arranged at opposite sides of said fulcrum line.
The device according to claim 13, characterized in that each of the first and second laminar bodies (30, 40) comprises a respective limiting appendage (47, 73) capable of making contact with the other one of the first and second laminar bodies (30, 40) to limit the rotation in the expanded position, said limiting appendages (47, 73) being arranged at opposite sides of said fulcrum line.
The device according to claim 4, characterized in that the first laminar body (30) further comprises an intermediate first fold line (74) arranged between the first and second edges (31, 32) and parallel thereto, and a second insertion portion (76) extending between at least one second stop edge (77), located between said intermediate fold line (74) and the first edge (31), and the first edge (31), and the second laminar body (40) further comprises an intermediate second fold line (75) arranged between the first and second edge (41, 42) and parallel thereto, and a second slot (80) located in an area between said intermediate second fold line (75) and the first edge (41), wherein said second insertion portion (76) of the first laminar body (30) is sized to be inserted in said second slot (80) of the second laminar body (40) until said second stop edge (77) of the first laminar body (30) makes contact with the second laminar body (40), and wherein the second stop edge (77) and the second slot (80) define a second fulcrum line.
The device according to claim 15, characterized in that the first laminar body (30) comprises at least one additional first hooking configuration (78) in or close to the intermediate first fold line (74), the second laminar body (40) comprises at least one additional second hooking configuration (79) in or close to the intermediate second fold line (75), and a second elastic band (66) is hooked at its ends to the additional first and second hooking configurations (78, 79).
The device according to claim 1, characterized in that the second laminar body (40) comprises at least two of said slots (43) formed between said first and second edges (41, 42) and parallel thereto, and at least two of said first laminar bodies (30) are arranged with their respective insertion portions (34) inserted in said slots (43) of the second laminar body (40), wherein each of the two first laminar bodies (30) includes at least one respective first hooking configuration, the second laminar body (40) includes at least one pair of second hooking configurations, and a corresponding pair of elastic bands (5) are hooked at their ends in said first and second hooking configurations to pull the first and second laminar bodies (30, 40) towards the expanded position.
A self-expandable foldable display case, of the type comprising at least one structure (10) formed from at least two panels (11, 12) facing one another and attached at the side edges thereof, and which in a collapsed situation adopt a planar configuration, and in a service position adopt a three-dimensional configuration capable of standing upright, and at least one expanding device arranged between said panels (11, 12) and comprising at least one laminar body attached to at least one of the panels (11, 12), said laminar body being capable of adopting a planar position together with the panels (11, 12) in said collapsed situation, and a pull element arranged to rotate, curve or bend the laminar body between the panels (11, 12) and thus cause the expansion of said structure (10), characterized in that said expanding device comprises:
a first laminar body (30) having opposed first and second edges (31, 32) and at least one insertion portion (34) extending between at least one stop edge (33) located between said first and second edges (31, 32) and one of said first and second edges (31, 32); and

a second laminar body (40) having opposed first and second edges (41, 42) and at least one slot (43) located in an area between said first and second edges (41, 42);

wherein said insertion portion (34) of the first laminar body (30) is sized to be inserted in said slot (43) of the second laminar body (40) until said stop edge (33) of the first laminar body (30) makes contact with the second laminar body (40); and

wherein the slot (43) and the stop edge (33) define a fulcrum line along which the first and second laminar bodies (30, 40) can rotate with respect to one another between a planar position, in which the first and second laminar bodies (30, 40) are superimposed, and an expanded position, in which the first and second laminar bodies (30, 40) are crossed.
The display case according to claim 18, characterized in that from at least one of said first and second edges (31, 32; 41, 42) of the first and second laminar bodies (30, 40) of the expanding device there extends at least one attachment flange (35) for the attachment to an inner face of one of the panels (11, 12) of the structure (10), wherein said attachment flange (35) is connected to the corresponding first or second laminar body (30, 40) by a fold line (35a).
The display case according to claim 19, characterized in that said attachment flange (35) is attached to the corresponding panel (11, 12) of the structure (10) in a position such that said fulcrum line is substantially parallel to the mentioned side edges of the panels (11, 12).
The display case according to claim 19, characterized in that said attachment flange (35) is attached to the corresponding panel (11, 12) of the structure (10) in a position such that said fulcrum line is substantially perpendicular to the mentioned side edges of the panels (11, 12).
The display case according to claim 21, characterized in that said structure (10) comprises two opposed panels (11, 12) with a convex arched configuration, and the first and second edges (31, 32; 41, 42) of the first and second laminar bodies (30, 40) of the expanding device are curved-convex according to said convex arched configuration of the two opposed panels (11, 12) of the structure (10).
The display case according to claim 21, characterized in that said structure (10) comprises two opposed panels (11, 12) with a planar configuration, and the first and second edges (31, 32; 41, 42) of the first and second laminar bodies (30, 40) of the expanding device are rectilinear according to said planar configuration of the two opposed panels (11, 12) of the structure (10).
The display case according to claim 21, characterized in that said structure (10) comprises two opposed panels (11, 12), one of which has a convex arched configuration and the other one is planar, and some of the first and second edges (31, 32; 41, 42) of the first and second laminar bodies (30, 40) of the expanding device are curved-convex according to said convex arched configuration of one of the opposed panels (11, 12) of the display case and the other ones of the first and second edges (21, 32; 41, 42) of the first and second laminar bodies (30, 40) of the expanding device are rectilinear according to said planar configuration of the other one of the opposed panels (11, 12) of the structure (10).
The display case according to claim 23 or 24, characterized in that said attachment flange (35) is formed in a rectilinear edge of the first and second edges (31, 32; 41, 42) of the first and second laminar bodies (30, 40) of the expanding device, wherein said rectilinear edge has a length covering the entire or a substantial part of the width of one of the planar panels (11, 12) of the structure (10) and the attachment flange (35) is attached to the inner surface of said planar panel (11, 12) of the structure (10).
The display case according to claim 22, 23 or 24, characterized in that at least one of the laminar bodies (30, 40) of the expanding device comprises at least one extension portion (37) extending from one of the opposed first and second edges (31, 32; 41, 42) thereof, and, in the expanded situation, said extension portion (37) is passed through a slot (67) formed in one of the panels (11, 12) of the structure (10) adjacent to the base thereof to make contact with the floor.
The display case according to claim 23, 24 or 25, characterized in that it comprises at least two structures (10a, 10b), each formed by at least two opposed panels (11a, 12a; 11b, 12b), at least one (11a, 11b) of which is a planar panel, and an additional panel (15) having a first side edge (15a) attached to a side edge of the planar panel (10a) of one of said two structures (10a) and a second side edge (15b) attached to a side edge of the planar panel (11b) of the other one of said two structures (10b), the two structures (10a, 10b) being configured to be arranged with their planar panels (11a, 11b) aligned with the additional panel (15) to jointly form a mural.
The display case according to any one of claims 18 to 27, characterized in that said at least two panels (11, 12) of the structure (10), or of each structure (10a, 10b) are formed from a single piece of laminar material (20), wherein the panels (11, 12) are arranged in parallel and connected to one another by longitudinal fold lines (17) delimiting said side edges of the panels (11, 12), and wherein from a side edge of one of the end panels there extends at least one attachment flange (16) connected to said piece of laminar material (20) by a longitudinal fold line (16a) and arranged to be attached to a side edge of the other one of the end panels.
The display case according to claim 28, characterized in that said piece of laminar material (20) comprises transverse fold lines (18) perpendicular to said longitudinal fold lines (17) through all the panels (11, 12), wherein said transverse fold lines (18) allow a folding of the structure (10) from said collapsed situation to a folded situation.
The display case according to claim 29, characterized in that each of the transverse fold lines (18) is formed by at least three adjacent transverse fold lines, said attachment flange (16) is interrupted in the areas where the transverse fold lines (18) join the side edge of the corresponding end panel, and the longitudinal fold lines (17) are aligned with longitudinal cuts (19) in areas of crossing with the transverse fold lines (18).
The display case according to claim 18, characterized in that it comprises a reinforcement member (52, 91) made of a laminar material, with an attachment area (52a, 96) attached to a face of an auxiliary panel (50, 92) associated with or forming part of the structure (10), said reinforcement member (52, 91) being provided with several fold lines (52b, 101) arranged such that said reinforcement member (52, 91) can adopt a collapsed situation, in which the reinforcement member (52, 91) is planar, and an expanded situation, in which the reinforcement member (52, 91) is bent in zigzag through said fold lines (52b, 101), adopting a substantially rigid three-dimensional configuration, at least one elastic element (53, 98) being arranged to contract said reinforcement member (52, 91) from said collapsed situation to said expanded situation.
The display case according to claim 31, characterized in that said auxiliary panel (92) is foldable through a transverse fold line (94), and the reinforcement member (91) has a transverse fold line (93) substantially perpendicular to the fold lines (101) of the reinforcement member (91) and superimposed on said transverse fold line (94) of the auxiliary panel (92), such that the auxiliary panel (92) and the reinforcement member (91) can only be folded jointly through their superimposed transverse fold lines (93, 94) if the foldable reinforcement member (91) is forced to said collapsed situation against the tension of said elastic element (98).
The display case according to claim 18, characterized in that it comprises an upper board (87) connected to the structure (10) by means of a hinge element (88) configured as a strip of laminar material provided with a middle fold line (89) dividing said hinge element (88) into two halves, one of said halves of the hinge element (88) being attached to an upper edge of at least one planar portion of one of the panels (11, 12) of the structure (10) and the other half being attached to the upper board (87), such that the hinge element (88) maintains the upper board (87) attached to the structure (10) and allows the upper board (87) to rotate between open and closed positions around said middle fold line (89).