ES2340125B1 - LINEAR EXTENSION DEVICE. - Google Patents

Abstract

Linear extender device.

The device comprises two sheets (10, 20) assembled so that they can slide guided the one with respect to the other. The first sheet (10) has a first configuration of anchor (121) and a first thrust region (11) in contact with an inner area of an extendable folding structure or expandable, and the second sheet (20) has a second configuration anchor (221) and a second thrust region (21) in contact with Another interior area of the folding structure. The first anchor configuration (121) of the first sheet (10) is located closer to the second thrust region (21) of the second sheet (20) than the second anchor configuration (221) of the second sheet (20). An elastic tensile element (301) is hooked on the first and second anchor configurations (121, 221) to push the first and second sheets (10, 20) towards a extended position

Description

Linear extender device.

Technical field

The present invention concerns an extender device made of cardboard sheets or other similar material in cooperation with one or more elastic tensile elements, which is applicable to an expandable or expandable folding structure made of cardboard panels or other similar and configured material. to adopt a retracted flattened situation in a folded position and an elongated or three-dimensional situation in an extended or expanded position. The present invention also concerns an expandable folding structure including such an element.
extender

Background of the invention

The patent FR-A-2760880 describes an exhibitor formed by a pair of cardboard or material laminar panels similar, generally rectangular, faced and united by their vertical edges forming two opposite edges. In a position folded, the two laminar panels are superimposed on one flattened situation. From the flattened situation, the exhibitor it can be folded like an accordion by a few fold lines horizontal panels to adopt a folded situation compact Between the two laminar panels are arranged elastic bands connected to one and the other of said opposite edges, so that the tension of the elastic bands pulls the edges opposite of the laminar panels bringing them closer to each other causing a bulging of the laminar panels and a deployment from the exhibitor towards an expanded situation in which the exhibitor He is able to stand up. Between the two laminar panels too limiter members are arranged in the form of some cardboard laminating elements or similar material that interfere with opposite edges and / or with elastic bands to counteract, by compression stiffness in a direction parallel to the plane of the laminar element, the tension of the elastic bands and limit the bulging of the laminar panels in position expanded. The possibility of a trained exhibitor is also foreseen by a single laminar panel, in which case the elastic bands and the limiting members act in relation to vertical edges opposite of it.

Documents EP-A-1395971 and FR-A-2795217 release variants of the exhibitor described in the mentioned patent FR-A-2760880 in which one or more of the laminar panels include a vertical fold line, of so that, when adopting the expanded situation, the panels instead of bulge fold down the vertical fold lines to adopt A prismatic configuration. The tension of the elastic bands acts to bring two edges or opposite areas of the exhibitor the one towards the other and the compressive stiffness of the limiting elements acts to counteract the tension of the elastic bands in the expanded situation. This construction has, among others, the drawback of not allowing the folding of the folding panels with the vertical fold lines into the structure, of so that in the flattened situation and in the folded situation compact the structure occupies a considerably larger space than which would occupy if the folding panels could be folded towards within the structure

Exhibition of the invention

According to a first aspect, this invention provides an applicable linear extender device, between others, to an expandable or expandable folding structure. He linear extender device of the present invention comprises first and second sheets, which, in operational situation, are assembled so that they can slide guided the one with respect to the other. The mentioned first sheet has a first anchor configuration and a first push region configured to be attached or in contact with an interior area of said expandable or expandable folding structure. The second sheet has a second anchor configuration and a second thrust region configured to be attached or in contact with another interior area of The expandable or expandable folding structure. In that situation operational, the aforementioned first anchor configuration of the first sheet is located closer to said second region of thrust of the second sheet that said second configuration of anchor of the second sheet. An elastic tensile element is hooked on said first and second anchor configurations of the first and second plates, with which the force of said elastic traction element makes the first and second slide foils in relation to each other in respective directions opposite extensions to automatically extend or expand the expandable or expandable folding structure. The extender device linear of the present invention allows subsequently to contract or fold the expandable or expandable folding structure, simply manually forcing the first and second plates to slide the one with respect to the other against the force of said elastic element of traction in respective opposite directions of contraction.

When the first and second sheets move in the aforementioned opposite directions of extension, the first and second push regions move away from each other while when the first and second sheets move in those directions opposite contraction, the first and second thrust regions are they approach each other.

In one embodiment, both the first region of thrust of the first blade as the second thrust region of the second sheet are respective first and second edges of push each other opposite, which may simply be embedded in a structure configuration, such as an edge internally concave, or attached to the corresponding inner zone of the structure by means of a fin or similar. In this case, it will also comply with the second anchor configuration of the second sheet will be located closer to the first pushing edge of the first sheet that the first anchor configuration of the first sheet.

In another embodiment, the first thrust region of the first sheet comprises a portion of the intended sheet to be attached internally to the corresponding area of the extendable or expandable folding structure, while the second thrust region of the second sheet is a thrust edge that it can be simply embedded in a configuration of the structure, for example an inwardly concave edge, or attached to the corresponding inner zone of the structure by means of a fin  or similar. Therefore, the first anchor configuration of the first sheet is located closer to the second edge of thrust of the second sheet than the second anchor configuration of the second sheet.

It is also planned that both regions of push be portions of the respective first and second sheets, or fins attached to them, intended to be glued internally to the corresponding areas of the folding structure extensible or expandable.

The extender device comprises preferably slip limiting means configured to limit the slippage of the first and second sheets by force of the elastic tensile element in a expanded position. For example, said means of limiting slip can comprise a first configuration of hitch formed on the first sheet and located, in the situation operational, between the first and second anchor configurations of both first and second sheets. So, when the first and second sheets slide in opposite directions of extension and the first hitch configuration of the first sheet reaches the position of the second anchor configuration of the second foil, the first hitch configuration engages with the elastic tensile element thus canceling the tensile capacity thereof and thereby limiting the sliding of first and second sheets by force of the elastic element of traction in an expanded position. Alternatively, the means of slip limitation may comprise settings formed in one and another of the first and second sheets arranged to interfere with each other in the extended position.

Guiding the relative movements of First and second sheets can be made by different means. For example, two elastic elements in the form of elastic bands endless arranged around two couples of first and second anchor configurations formed symmetrically and in parallel in opposite edges of the first and second sheets act to keep the two sheets together, to push the movements relative sliding of both and to guide such movements. Alternatively, the two sheets may have respective lines of longitudinal fold overlays for guiding, or one of the sheets may have one or more cross slits in which it is slidingly inserted a portion of the other sheet, or a of the sheets can have a pair of longitudinal tabs slidingly hugging opposite edges of each other sheet.

The linear extender device of the present invention may be applied, for example, to expanding a expandable folding structure of polygonal cross section, made for example of panels of cardboard or similar material attached articulated by its edges, which can serve, for example, as a column-shaped display. Alternatively, the linear expander device of the present invention can be used in a huge variety of applications, such as, by example, to emerge a surprise content from an envelope, to automatically open the lid of a box or to provide a folding stand for an image or information support panel, Just like a picture frame. A person skilled in the art will be other applications will easily occur.

According to a second aspect, the present invention provides an expandable folding structure comprising the minus four laminar panels articulated together by their edges sides so that you can adopt a flattened configuration, in which said laminar panels are parallel and total or partially overlaid, and an expanded configuration, in which the laminar panels form a hollow body of cross section polygonal. At least one device is arranged between the panels linear extender according to the present invention as has been described above, which include two sheets linked the one to the other by at least one elastic tensile element and provided of respective thrust edges configured and arranged to press internally against areas of at least two of said laminar panels by force of said elastic element of traction to bring the expandable folding structure to said expanded configuration.

Two of the structure's laminar panels they are facing flat panels and the other two panels laminar are first and second folding panels likewise faced. Each of said folding panels is divided into two panel halves by a respective fold line longitudinal. The first pushing edge of the first sheet of the extender device is connected to one of said panel halves of the first folding panel and the second pushing edge of the second sheet of the extender device is connected to one of said panel halves of the second folding panel, so that the expandable folding structure can be taken to the configuration expanded by the force of the elastic tensile element and can be forced manually to the configuration contracted against the force of the elastic tensile element. Obviously the panels folding of the structure are folded with the edges inwards of the structure, so that the structure in the flattened situation or in a compact folded situation it occupies a smaller space than if the folding panels were folded out, as is the case with the expandable folding structures of the prior art.

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Another aspect of the present invention makes reference to an improved method of manufacturing a display by means of an expandable folding structure of the present invention, as described above. According to the method Traditional, manufacturing exhibitors based on structures expandable folding made of cardboard or similar material entails a long process that usually involves several different industries: the industry that dies the panels of cardboard making cuts and marking creases for the lines of fold; the industry that prints images and / or information about the die cut cardboard; the one that plasticizes the structure; the industry that manipulate the structure for assembly and setup operational, etc. This generates numerous storage costs, transport and handling that produce a high final cost. For small productions this traditional method is in practice unfeasible for economic reasons.

The process of the present invention allows to manufacture expandable folding displays quickly and economical, using digital printing, and saving mostly on transport costs, and die cutting. The procedure includes first make expandable folding structures of according to the present invention by punching and marking of blank cardboard pieces including the outer contours, creases for the bending lines that define the laminar panels and optionally other cuts and / or clefts that define various configurations On at least one side of the die cut piece they have formed anchor points punched out by which the structure is fastened. These anchor points are defined by slits surrounding a portion of material, which is attached to the rest of the blank piece stamped only by a few points of union that interrupt the cracks. Then the blank stamped structures are shipped still disassembled (flat) to a digital printing press where printing is done digital images and information on a substrate sheet preferably thin, which can then be attached on the blank pieces preferably cut in the same place of the printing. Under the thinness of the printing sheet digital, when the digital printing sheet is adhered to the blank piece die cut, cuts, fold lines and slits of the blank piece stamped are automatically marked in the sheet of digital printing, so that they are not necessary further punching and marking operations. Finally, the portions of blank blank and sheet material digital printing corresponding to the mentioned points of anchor can be removed from the exhibitor by following the mentioned slits with a blade or cutter using a simple manual operation that can be performed, for example, in the same Print shop. Alternatively, the corresponding material to the anchor points can be removed using a small manual die-shaped buffer. After these operations, the Exhibitor is ready to be assembled in the usual way.

Brief description of the drawings

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

Fig. 1 is a side view of some first and second sheets that are part of a linear extender device according to a first embodiment of the present invention;

Fig. 2 is a side view of the device linear extender of the first embodiment in one position contracted;

Fig. 3 is a side view of the device linear extender of the first embodiment in one position extended;

Fig. 4 is a schematic top view of the linear extender device of the first embodiment;

Fig. 5 is a side view of some first and second sheets that are part of a linear extender device according to a second embodiment of the present invention;

Fig. 6 is a side view of the device linear extender of the second embodiment;

Fig. 7 is a side view of some first and second sheets that are part of a linear extender device according to a third embodiment of the present invention;

Fig. 8 is a side view of the device linear extender of the third embodiment in one position contracted;

Fig. 9 is a side view of the device linear extender of the third embodiment in one position extended;

Fig. 10 is a side view of a first and second sheets that are part of a linear extender device according to a fourth embodiment of the present invention;

Fig. 11 is a side view of the device linear extender of the fourth embodiment;

Fig. 12 is a schematic top view of an expandable folding structure according to an embodiment of the present invention in a flattened situation;

Fig. 13 is a schematic top view of the expandable folding structure of Fig. 12 in a situation expanded;

Fig. 14 is a perspective view of the expandable folding structure of Figs. 12 and 13 in a situation expanded;

Fig. 15 is a perspective view of the expandable folding structure of Fig. 14 initiating a fold from a flattened situation to a folded situation compact;

Fig. 16 is a perspective view of the expandable folding structure of Fig. 14 in a situation close to the compact folded situation;

Fig. 17 is a side view of a first and second sheets that are part of a linear extender device according to a fifth embodiment of the present invention;

Fig. 18 is a side view of the device linear extender of the fifth embodiment in arrangement operational;

Fig. 19 is a side view of a linear extender device according to a sixth embodiment of the present invention in operative arrangement;

Fig. 20 is a side view of a first and second sheets that are part of a linear extender device according to a seventh embodiment of the present invention;

Fig. 21 is a side view of the device linear extender of the seventh embodiment in arrangement operational;

Fig. 22 is a side view of a linear extender device according to an eighth embodiment of the present invention in operative arrangement;

Fig. 23 is a side view of a linear extender device according to a ninth embodiment of the present invention in operative arrangement;

Fig. 24 is a side view is a view side of first and second sheets that are part of a linear extender device according to a tenth embodiment of the present invention;

Fig. 25 is a side view of the device linear extender of the tenth embodiment in arrangement operational;

Fig. 26 is a side view is a view side of first and second sheets that are part of a linear extender device according to an eleventh embodiment of the present invention;

Fig. 27 is a side view of the device linear extender of the eleventh embodiment in disposition operational;

Fig. 28 is a side view of an example of application comprising an envelope and a surprise content based on the linear extender device of the eleventh embodiment;

Fig. 29 is a side view of the content surprise of Fig. 28 automatically emerging from the envelope when this one is open;

Fig. 30 is a side view of another example of application comprising an envelope and a surprise based content in a variant of the eleventh linear extender device realization;

Fig. 31 is a side view of the content surprise of Fig. 30 automatically emerging from the envelope when this one is open;

Fig. 32 is a perspective view of a box equipped with a linear extender device of the present invention applied to provide an automatic opening of the top;

Fig. 33 is a perspective view of a Image or information support equipped with an extender device linear of the present invention applied to provide an easel in a work position;

Fig. 34 is a schematic side view of the image or information support of Fig. 33 with the easel on the work position;

Fig. 35 is a schematic side view of the image or information support of Fig. 33 with the stand in a folded position;

Fig. 36 is a side view of a piece of blank cardboard stamped and marked obtained according to a first step in a manufacturing procedure for an exhibitor based on a expandable folding structure of the present invention, with a enlarged detail showing a die-cut anchor point;

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Fig. 37 is a perspective view that illustrates the application of a digital print on the piece of blank cardboard stamped and marked in Fig. 36 to form a final piece according to a second step in the manufacturing process of the exhibitor; Y

Fig. 38 is a perspective view of the final piece that forms the exhibitor, with an expanded detail that illustrates the removal of a portion of the final piece corresponding to the anchor point according to a third step in the Exhibitor manufacturing procedure.

Detailed description of some embodiments

Referring firstly to Figs. 1 to 4 a first embodiment of the extender device is described linear of the present invention, which is applicable to a expandable or expandable folding structure. The extender device linear according to this first embodiment comprises two sheets 10, 20 (shown separately in Fig. 1) of a sheet material relatively rigid, such as cardboard or other similar material, and a pair of elastic tensile elements 301, 302 such as ones endless elastic bands, which, in an operational situation, link the two sheets 10, 20 with each other (as shown in Figs. 2 to 4).

As best seen in Fig. 1, the first and second sheets 10, 20 have a shape approximately rectangular flat and are substantially symmetrical. The first sheet 10 has a couple of first configurations of anchor 121 on opposite sides upper and lower, and a first thrust region that defines a first thrust edge 11 in one side end Similarly, the second sheet 20 has a pair of second anchor configurations 221, 222 on sides upper and lower opposites and a second thrust region that defines a second thrust edge 21 at a side end opposite to said first pushing edge 11.

In the operational situation shown in Figs. 2 to 4, the first and second sheets 10, 20 are assembled, partially overlapping (Fig. 4), so that they can slide linearly guided with respect to each other between positions contracted (Fig. 2) and extended (Fig. 3). The first elastic element Traction 301 is hooked on the first and second anchor configurations 121, 221 of the upper side of the first and second sheets 10, 20 while the second elastic element Traction 302 is engaged in the first and second anchor configurations 122, 222 of the lower side of the first and second sheets 10, 20. In addition, in the operational situation (Figs. 2 to 4), the first and second sheets 10, 20 are mutually positioned so that, in any position including the mentioned contracted and extended positions, the first edge of thrust 11 of the first sheet 10 is closer to the second anchor configurations 221, 222 of the second sheet 20 that of the first anchor configurations 121, 122 of the first blade 10, and, analogously, the second thrust edge 21 of the second sheet 20 is closer to the first hitch configurations 121, 122 of the first sheet 10 which of the second anchor configurations 221, 222 of the second sheet 20. In addition, preferably, the first and second elements traction elastics 301, 302 are sized so that, in any position including the mentioned positions contracted and extended, are more or less stressed and elastically deformed Consequently, the elastic recovery force of the first and second elastic tensile elements 301, 302 ago slide the first and second sheets 10, 20 the one relative to the another in respective opposite directions of extension, in the that the first and second thrust edges 11, 21 move away the one of the other. Conversely, the first and second thrust edges 11, 21 of the first and second sheets 10, 20 can be forced manually move in respective opposite directions of contraction, in which the first and second thrust edges 11, 21 they approach each other, against the elastic force of the first and second tensile elastic elements 301, 302. Thus, in the contracted position shown in Fig. 2 the elastic elements of traction 301, 302 are very elastically deformed and subjected to a high voltage, and therefore have a high level of accumulated energy that is used to automatically move the first and second sheets 10, 20 to the extended position shown in Fig. 3, in which the elastic tensile elements 301, 302 they are slightly elastically deformed and subject to low tension.

The first push region, and more specifically the first pushing edge 11, of the first sheet 10 is configured to be attached or in contact with a zone interior of the aforementioned folding structure extensible or expandable, and the second thrust region, and more specifically the second pushing edge 21, of the second sheet 20 is configured to be attached or in contact with another zone inside the folding or expandable structure, of so that the movement of the first and second plates 10, 20 of the extensor device driven by the force of the elements traction elastics 301, 302 in the respective directions of expansion acts to automatically extend or expand the folding structure up to an extended or expanded situation. Conversely, the folding structure can be folded up to a contracted situation manually forcing the first and second sheets 10, 20 of the extender device to move in the respective opposite directions of contraction against the force of the first and second elastic tensile elements 301, 302. Further down, in relationship with Figs. 12-16 and 24-29, various embodiments of expandable or expandable folding structures to which it is applied the extender device of the present invention. In some cases, and depending on the configuration of it, when the expandable or expandable folding structure reaches its situation expanded the inner areas of it in contact with the thrust regions of the first and second blades 10, 20 of the extender device provide a limit for the extension of the extender device However, it is generally preferred that the extender device include a means of limiting slip set to limit the slip of the first and second sheets 10, 20 by the force of the elastic element of traction 301 in a predetermined expanded position.

In the first embodiment shown in Figs. 1 to 4, said slip limiting means comprise a pair of first hitch configurations 131, 132 formed in the first sheet 10 and located on the upper and lower sides between the respective first anchor configurations 121, 122 and the first pushing edge 11 (Fig. 1). In the operational situation, the mentioned first hitch configurations 131, 132 are located between the first anchor configurations 121, 122 of the first sheet 10 and the second anchor configurations 221, 222 of the second sheet 20, and in line with them (Fig. 2), of so that said first hitch configurations 131, 132 are engage with the respective first and second elastic elements of traction 301, 302 when, when sliding the first and second sheets 10, 20 in the opposite directions of extension, the first hitch configurations 131, 132 reach the position of the second anchor configurations 221, 222 of the second sheet 20 (Fig. 3), thus canceling the tensile capacity of the elastic tensile elements 301, 302 and limiting the sliding of the first and second sheets 10, 20 by action of the force of the elastic tensile elements 301, 302 in a default expanded position. In a similar way, the second sheet 20 has a pair of second configurations of hitch 231, 232 located on the upper and lower sides between the respective second anchor configurations 221, 222 and the second pushing edge 21 (Fig. 1). In the operational situation, the mentioned second hitch configurations 231, 232 are located between the second anchor configurations 221, 222 of the second sheet 20 and the first anchor configurations 121, 122 of the first sheet 10, and in line with them (Fig. 2), and are hooked with the respective first and second elements traction elastics 301, 302 when the extender device it reaches the extended position (Fig. 3).

As shown in Figs. 2 and 3, in the first embodiment of the extender device, the first sheet 10 it has formed a first couple of first configurations of anchor and hitch 121, 131 on the upper side and a second couple of first anchor and hitch configurations 122, 132 in the bottom side ,. The first couple is separated in parallel from the Second couple In a similar manner, the second sheet 20 has formed a first pair of second anchor configurations and hook 221, 231 on the upper side and a second pair of second anchor and hitch configurations 222, 232 on the side lower, said first and second couples being separated in parallel to each other. Both first and second elastic elements of traction 301, 302 are arranged mutually parallel and parallel to the sliding direction of the first and second sheets 10, 20. The first elastic tensile element 301 is in the form of a endless elastic band arranged around the first pairs of first and second anchor and hitch configurations 121, 131 and 221, 231 located on the upper side of the respective first and second sheets 10, 20, and similarly, the second element elastic traction 302 is in the form of an endless elastic band arranged surrounding the second pairs of first and second anchor and hitch configurations 122, 132 and 222, 232 located on the lower side of the respective first and second sheets 10, 20. With this arrangement, the first and second elastic elements traction 301, 302 act in cooperation with the first and second pairs of first and second anchor configurations and hitch 121, 131 and 221, 231; 122, 132 and 222, 232 to maintain together the first and second sheets 10, 20 and to guide linearly the relative landslides of the first and second sheets 10, 20 in the opposite directions of extension and contraction, in addition to activate these movements.

In relation now to Figs. 5 and 6 a second embodiment of the extender device is described, which also comprises first and second sheets 10, 20 of approximately rectangular flat shape and substantially symmetrical. However, here, the first and second sheets 10, 20 comprise respective first and second longitudinal fold lines 14, 24 (Fig. 5), parallel to the opposite directions of extension and contraction, forming. Both first and second sheets 10 are bent at an angle by their respective first and second fold lines 14, 24 and partially overlapping (Fig. 6), so that the folds by said first and second overlapping fold lines 14, 24 act to guiding the relative slides of the first and second sheets 10, 20 in the opposite directions of extension and contraction and to confer to the first and second sheets 10, 20 greater compression resistance in a direction parallel to the opposite directions of extension and
contraction.

In this second embodiment, the first sheet 10 has a single first anchor configuration 11 formed in a rear edge at a side end opposite the first edge of push 11 and in alignment with the corresponding first line of fold 14, and the second sheet 20 has a single second anchor configuration 21 formed on a trailing edge in a lateral end opposite the second thrust edge 21 and in alignment with the corresponding second fold line 24. The first sheet 10 has a first elongated window 15 formed in alignment with the first fold line 14, and the second sheet 20 has a second elongated window 25 in alignment with the second fold line 24. A single elastic element of traction 301, for example in the form of an endless elastic band, is hooked to the first anchor configuration 121 of the first sheet 10 through said second elongated window 25 of the second sheet 20, and to the second anchor configuration 221 of the second sheet 20 through said first elongated window 15 of the first sheet 10. Internal edges of the first and second windows 15, 25 provide respective first and second hitch configurations 131, 231, each of which is arranged in an operational situation between the first anchor configuration 121 of the first sheet 10 and the second anchor configuration 221 of the second sheet 20, so that the first and second hitch configurations 131, 231 are engage with elastic tensile element 301 when, at slide the first and second sheets 10, 20 in the directions opposite extension, the first and second configurations of hitch 131, 231 respectively reach the positions of the first and second anchor configurations 121, 221 of the first and second sheets 10, 20, thus limiting the relative movement of the first and second sheets 10, 20 in an extended position default

Next, and in relation to Figs. 7 a 9 a third embodiment of the extender device is described, in which the first and second sheets 10, 20 (shown separately in Fig. 7) they include the same characteristics and substantially the same arrangement as the first and second sheets 10, 20 of the first embodiment (compare with Fig. 1), so that your Detailed description will be omitted. The difference is that here the first and second elastic tensile elements 301, 302, the which are also in the form of endless elastic bands, are arranged mutually crossed (Figs. 8 and 9), with the first element traction elastic 301 engaged in the first configuration of anchor 121 on the upper side of the first sheet 10 and on the second anchor configuration 222 on the bottom side of the second sheet and the second elastic tensile element 302 hooked on the first anchor configuration 122 on the side bottom of the first sheet 10 and in the second configuration of anchor 221 on the upper side of the second sheet 20. Fig. 8 shows the first and second sheets in the contracted position and with the first and second elastic tensile elements 301, 302 stressed and ready to start their movement in opposite directions of extension. With this cross arrangement, the first and second hitch configurations 131, 132 and 231, 232 of the first and second sheets 10, 20 also engage with the first and second elastic tensile elements 301, 302 when they reach the respective positions of the first and second anchor configurations 121, 122 and 221, 222 limiting the movement in a predetermined extended position (Fig. 9). The first and second tensile elastic elements 301, 302 act in cooperation with the first and second couples of first and second anchor and hitch configurations 121, 131; 221, 231 and 122, 132; 222, 232 additionally to hold the first and second sheets 10, 20 and to guide their movements in the opposite directions of extension and contraction.

In relation to Figs. 10 and 11 describes then a fourth embodiment of the extensor device of the present invention, which comprises first and second sheets 10, 20 (shown separately in Fig. 10) so approximately rectangular flat and substantially symmetrical, the which include the same characteristics as the first and second sheets 10, 20 of the first embodiment (shown in Fig. 1), although with a different disposition. In this fourth embodiment, the first sheet 10 has a pair of first windows 151 formed, 152 upper and lower, elongated, located one above the other and parallel to the relative sliding direction of the first and second sheets 10, 20, and the second sheet 20 has a pair formed of second windows 251, 252 upper and lower, elongated, located one above the other parallel to the direction of relative slippage of the first and second sheets 10, 20 and in alignment with the aforementioned first windows 151, 152 of the first Plate 10. Here, the first and second pairs of first and second anchor and hitch configurations 121, 131; 221, 231 and 122, 132; 222, 232 are formed at opposite inner edges of said first and second windows 151, 152; 251, 252 higher and lower formed in the first and second sheets 10, 20, respectively.

In this fourth embodiment, as in the first embodiment, a first tensile elastic element 301 in endless elastic band shape is arranged surrounding the first couples of first and second anchor and hitch configurations 121, 131 and 221, 231 located in the first and second windows 151, 251 upper of the respective first and second sheets 10, 20, and a second elastic tensile element 302 in the form of a band elastic endless is arranged surrounding the second pairs of first and second anchor and hitch configurations 122, 132 and 222, 232 located in the first and second windows 152, 252 of the respective first and second sheets 10, 20. With this arrangement, the first and second elastic tensile elements 301, 302 act in cooperation with the first and second couples of first and second anchor and hitch configurations 121, 131 and 221, 231; 122, 132 and 222, 232 to keep the first and second together sheets 10, 20 and to linearly guide relative landslides of the first and second sheets 10, 20 in the opposite directions extension and contraction, in addition to activating these movements. The operation is the same as in the first embodiment.

In Figs. 12 to 16 a structure is shown expandable folding according to an embodiment of the second aspect of the present invention, which comprises four panels laminar 41, 42, 43, 44, of a relatively laminar material rigid, such as cardboard or similar, articulated jointly by their side edges so that you can adopt a configuration flattened (Fig. 12), wherein said laminar panels 41, 42, 43, 44 are mutually parallel and totally or partially overlapping, and an expanded configuration (Fig. 13), in which the panels laminar 41, 42, 43, 44 form a hollow sectional body polygonal transverse Two of said laminar panels are about flat panels 41, 42 facing each other and the other two panels are about first and second folding panels 43, 44 facing each other which is divided into two panel halves 43a, 43b; 44a, 44b by a respective longitudinal fold line 45, 46. The expandable folding structure includes a couple of devices extenders, which may be in accordance with any of the first, second, third and fourth embodiments of the first aspect of the present invention described above in relation to Figs. 1 to 11. That is, and in a very short way, each device extender comprises first and second sheets 10, 20 linked to each other by one or more elastic tensile elements 301 and provided with respective thrust edges 11, 21 capable of press internally against areas of two of said panels laminar 41, 42, 43, 44 by force of said elastic element of traction 301 to bring the expandable folding structure to said expanded configuration.

In the embodiment shown in Figs. 12 to 16, the first pushing edge 11 of the first sheet 10 of each of the two extender devices is connected to a respective of said panel halves 43a, 43b of the first folding panel 43 and the second pushing edge 21 of the second sheet 20 of each of the extender devices is connected to a respective one of the panel halves 44a, 44b of the second folding panel 44 (Figs. 12 and 13). Thus, the expandable folding structure can pass automatically of the flattened configuration shown in Fig. 12 to the expanded configuration shown in Fig. 13 accordingly of the movement of the first and second plates 10, 20 of the extender devices in opposite directions of extension driven by the force of elastic tensile elements 301 and can be manually forced to pass the configuration expanded to the configuration contracted against the force of elastic tensile elements 301 applying an external pressure on, for example, said flat panels 41, 42 facing each other.

Preferably, from the respective first and second thrust edges 11, 21 of the first and second blades 10, 20 extend fins (not shown) connected articulated to the first and second plates 10, 20, for example by fold lines, which are intended to be glued by adhesive to the corresponding halves 43a, 43b, 44a, 44b of the first and second folding panels 43, 44. Alternatively, from the respective first and second thrust edges 11, 21 of the first and second sheets 10, 20 can extend fins rigid (not shown) intended to be inserted into corresponding slits formed in the corresponding halves 43a, 43b, 44a, 44b of the first and second folding panels 43, 44. Obviously a combination of glued fins and inserted fins, or the use of other means of connection, including the fitting of one or more of the respective first and second edges of push 11, 21 of the first and second sheets 10, 20 at vertices interiors formed by the conjunction of two panels or parts of expandable folding structure panel. One skilled in the art understand that a folding structure is equally possible expandable formed by four laminar panels 41, 42, 43, 44 identical to those shown in Figs. 12 to 16 and a single expander device with the first and second thrust edges 11, 21 of its first and second sheets connected to a single half of each folding panel 43, 44.

As shown in Figs. 14 to 16, the laminar panels 41, 42, 43, 44 of the folding structure expandable are crossed by transverse fold lines 48, which are perpendicular to edges formed between adjacent edges of the laminar panels 41, 42, 43, 44 and are mutually aligned. The transverse fold lines divide the structure in several overlapping sections, and in each section are internally arranged a pair of extension devices. So, to from the flattened configuration shown in Fig. 12, the expandable folding structure can be folded by said lines cross bending 48 following the steps shown in the Figs. 15 and 16 to a compact folded position, which is a stable position because successive folds prevent a spontaneous extension of the extensor devices. But nevertheless, when starting from the compact folded configuration starts Manually deploy the structure to the configuration flattened, the energy accumulated in the elastic elements of traction 301 triggers a full automatic deployment of the structure to the expanded configuration shown in Figs. 13 and 14.

In relation now to Figs. 17 and 18 se describes a fifth embodiment of the extensor device of the present invention, which is formed by first and second sheets 10, 20 (shown separately in Fig. 17) linked each other by an elastic tensile element 301 (Fig. 18). In this In this case, the two sheets 10, 20 are of different shapes. The first sheet 10 is substantially rectangular flat and has a first thrust region 11 adjacent to a side end, a pair of first anchor configurations 121, 122 at the other end opposite side, and cuts that define guide fins upper and lower 141, 142, facing, connected to the first sheet along respective upper and lower fold lines 143, 144 parallel to the relative sliding direction of the first and second sheets 10, 20. The second sheet 20 is of shape substantially rectangular flat and has a second region of thrust 21 adjacent to a side end opposite the first region of thrust 11 of the first sheet 10, a couple of seconds anchor configurations 221, 222 at the other side end opposite, and upper and lower edges 241, 242 parallel to the relative sliding direction of the first and second sheets 10, 20. The distance between said upper and lower edges 241, 242 of the second sheet 20 is slightly shorter than the distance between the upper and lower fold lines 143, 144 of the first sheet 10.

In the operational situation shown in Fig. 18, the first and second sheets 10, 20 are assembled partially overlapping and with the upper and lower edges 241, 242 of the second sheet 20 arranged between the fold lines upper and lower 143, 144 and below the mentioned fins of upper and lower guide 141, 142 of the first sheet 10. With this arrangement, the upper and lower guide fins 141, 142 of the first sheet 10 in cooperation with the upper edges e bottom 241, 242 of the second sheet 20 act to maintain together the first and second sheets 10, 20 and to guide their movements in opposite directions of extension and contraction. The elastic tensile element 301, which can be a band elastic endless, is hooked on the first configurations of anchor 121, 122 of the first sheet 10 and the second anchor configurations 221, 222 of the second sheet 20 for actuate the automatic extension movement as described in relation to the previous embodiments. Alternatively with the same first and second sheets 10, 20 could be used two elastic tensile elements, one on the upper side and the other on the bottom side.

A sixth embodiment is shown in Fig. 19 of the extensor device of the present invention comprising first and second sheets 10, 20 linked together by a pair of elastic tensile elements 301, 302. The first and second sheets 10, 20 have the same characteristics and arrangement as the first and second sheets 10, 20 of the fifth embodiment described above in relation to Figs. 17 and 18 except that the second sheet 20 has a single second configuration of hitch 221. Here, the two elastic tensile elements 301, 302, which may be, for example, elastic bands endless, they are arranged surrounding the first and second sheets 10, 20 and engaged in the first anchor configurations 121, 122 of the first sheet 10 and in the only second configuration of anchor 221 of the second sheet 20. The side edge adjacent to the first thrust region 11 of the first sheet 10 acts as a limit for device extension when as a result of relative movement of the first and second sheets 10, 20 in the extension address the only second anchor configuration 221 of the second sheet 20 reaches the position of said lateral edge of the first sheet 10 and the elastic tensile elements 301, 302 get hooked with it.

A seventh is described below. embodiment in relation to Figs. 20 and 21, which includes first and second sheets 10, 20 (shown separately in the Fig. 20) linked to each other by an elastic tensile element 301 (Fig. 21). The first sheet 10 is substantially flat rectangular and has a first adjacent thrust region 11 to one side end, a couple of first anchor configurations 121, 122 at the other opposite side end, and a pair of openings guide 160 elongated in the direction transverse to the direction of relative slippage of the first and second sheets 10, 20 and limited by respective upper and lower edges 161, 162 mutually aligned and parallel to the sliding direction relative of the first and second sheets 10, 20. The second sheet 20 is substantially rectangular flat and has a second thrust region 21 adjacent to a side end opposite to the first push region 11 of the first sheet 10, a pair of second anchor configurations 221, 222 at the other end opposite side, and upper and lower edges 241, 242 parallel to the relative sliding direction of the first and second sheets 10, 20. The distance between said upper edges e lower 241, 242 of the second sheet 20 is slightly lower than the distance between the mentioned upper and lower edges 161, 162 of the guide openings 160 of the first sheet 10.

In the operational situation shown in Fig. 21, the first and second sheets 10, 20 are assembled partially overlapping and with the second sheet 20 inserted into through the guide openings 160 of the first sheet 10. With this arrangement, the guide openings 160 of the first sheet 10 and its upper and lower edges 161, 162 in cooperation with the upper and lower edges 241, 242 of the second sheet 20 act to hold together the first and second sheets 10, 20 and to guide your movements in the opposite directions of extension and contraction. The elastic tensile element 301, which can be an endless elastic band, is hooked on the first anchor configurations 121, 122 of the first sheet 10 and in the second anchor configurations 221, 222 of the second sheet 20 to activate the automatic extension movement as described in relation to the previous embodiments. Alternatively, with the same first and second sheets 10, 20 two elastic tensile elements could be used, one on the side upper and the other on the lower side.

An eighth embodiment is shown in Fig. 22 of the extensor device comprising first and second sheets 10, 20 with the same characteristics as sheets 10, 20 of the fifth embodiment shown in Figs. 17 and 18, except that here the second sheet 20 has a single second configuration of anchor 221 formed by a cut in a middle region of the second sheet 20. An elastic tensile element 301, for example in the form of an endless elastic band, it is hooked on the first anchor configurations 121, 122 of the first sheet 10 and in the only second anchor configuration 221, 222 of the second sheet 20.

A ninth embodiment is shown in Fig. 23 of the extensor device comprising first and second sheets 10, 20 with the same characteristics as sheets 10, 20 of the seventh embodiment shown in Figs. 20 and 21, except that here the first sheet 10 includes a single guide opening 160 bounded by upper and lower edges 161, 162 and the second sheet 20 has a single second anchor configuration 221 formed by a cut in a middle region of the second sheet 20. An elastic tensile element 301, for example in the form of an endless elastic band, is hooked on the first anchor configurations 121, 122 of the first sheet 10 and in the only second anchor configuration 221, 222 of the second sheet twenty.

In the fifth, sixth, seventh and ninth embodiments described above, the first thrust region 11 of the first sheet 10 generally comprises a portion of the first sheet 10 itself intended to be, for example, held manually or glued by adhesive to an inner zone of the corresponding expandable or expandable folding structure, while the second pushing region 21 of the second sheet 20 has a pushing edge 21 configured to be in contact with the corresponding inner zone of the expandable or expandable folding structure. Alternatively, in these embodiments the first push region 11 of the first sheet 10 may also be a push edge 11 and optionally the portion of the first sheet 10 intended to be glued may be formed by one or more fins (not shown) extending , for example, from said pushing edge 11. Alternatively, the pushing edge 21 of the second sheet 20 may be associated with one or more fins intended to be glued to a corresponding inner area of the folding structure.
expansible.

In relation to Figs. 24 and 25 describes then a tenth embodiment of the linear extender device of the present invention, which comprises first and second sheets 10, 20 (shown separately in Fig. 24) linked each other by an elastic tensile element 301 (Fig. 25). The first sheet 10 is substantially rectangular flat and it has a first thrust region 11 adjacent to one end lateral, a pair of upper and lower fold lines 163, 164 longitudinal parallel to the relative sliding direction of the first and second sheets 10, 20 and separated by a distance, and a couple of first anchor configurations 121, 122 near the other opposite side end. The mentioned fold lines upper and lower 163, 164 delimit respective fins of guide 170, 171 adjacent to upper and lower edges of the first sheet 10. The first anchor configurations 121, 122 they are formed by some cuts that have the beginning and the end in alignment with said upper and lower fold lines 163, 164 and extending inside said guide fins 170, 171. The second sheet 20 is substantially rectangular flat in shape and has a second thrust region 21 adjacent to a side end opposite the first thrust region 11 of the first blade 10, a second anchor configuration 221 formed by a cut centered near the other opposite side end, and some edges upper and lower 267, 268 parallel to the direction of relative slippage of the first and second sheets 10, 20. The distance between said upper and lower edges 267, 268 of the second sheet 20 is slightly less than the distance of separation between the upper and lower double lines 163, 164 of the first sheet 10.

In the operational situation shown in Fig. 25, the first and second sheets 10, 20 are assembled partially overlapping and with the upper and lower edges 267, 268 of the second sheet 20 inserted below the fins of guide 170, 171 of the first sheet 10, which have been previously folded by the upper and lower fold lines 163, 164. With this arrangement, guide fins 170, 171 of the first sheet 10 cooperate with the upper and lower edges 267, 268 of the second sheet 20 act to hold the first together and second plates 10, 20 and to guide their movements in the opposite directions of extension and contraction. The element elastic tensile 301, which can be an elastic band endless, is hooked on the first anchor configurations 121, 122 of the first sheet 10 and in the second configuration of anchor 221 of the second sheet 20 to drive the movement Automatic extension as described in relation to the previous embodiments. Elastic tensile element parts 301 between the first and second anchor configurations 121, 122, 221 are arranged above guide fins 170, 171 ensuring that they do not get up.

In relation to Figs. 26 and 27 describes then an eleventh embodiment of the extender device linear of the present invention, which comprises first and second sheets 10, 20 (shown separately in Fig. 26) linked to each other by an elastic tensile element 301 (Fig. 27). Both first and second sheets 10, 20 are shaped substantially rectangular flat, of similar dimensions, and they have respective upper and lower edges 165, 166; 265, 266 parallel to the relative sliding direction of the first and second sheets 10, 20. The first sheet 10 has a first thrust region 11 adjacent to a side end and a pair of first anchor configurations 121, 122 formed in said upper and lower edges 165, 166 near the other side end opposite. The second sheet 20 has a second thrust region 21 adjacent to a side end opposite the first thrust region 11 of the first sheet 10, and a second anchor configuration 221 centered on one edge of the other opposite side end. The second sheet 20 further comprises a retaining tab 269 formed by a cut centered near the second configuration of anchor 221, a pair of first clamping cuts 263, 264 adjacent to the upper and lower edges 265, 266, and a pair of second clamping cuts 270, 271 further from the edges upper and lower 265, 266 and closer to the second region of push 21.

In the operational situation shown in Fig. 27, the first and second sheets 10, 20 are assembled partially overlapping and with the respective upper edges and lower 165, 166; 265, 266 substantially aligned, although in the figures are somewhat displaced for clarity of the He drew. The elastic tensile element 301, which can be a endless elastic band, is hooked on the first anchor configurations 121, 122 of the first sheet 10 and in the second anchor configuration 221 of the second sheet 20 for actuate the automatic extension movement as described in relation to the previous embodiments. Parts of the item traction elastic 301 between the first and second anchor configurations 121, 122, 221 are arranged below of the second sheet 20, so that it is cleared. A sheet or booklet 90 (shown by dashed lines in Fig. 27) can be attached to the second sheet 20 with a rear edge inserted below said holding tab 269 and front corners inserted in said first cuts of clamp 263, 264. In addition, a card 91 (shown by lines of strokes in Fig. 27) can be attached to the second sheet 20 with rear corners inserted in said second cuts of clamping 270, 271. The linear extender device of this eleventh realization does not include specific means to guide and maintain together the first and second sheets 10, 20 since such functions can be performed by the extendable folding structure of according to an application example, as described in continuation.

In Figs. 28 and 29 an example of application of the extender device of the eleventh embodiment, where the extendable folding structure is an envelope 30 provided with upper and lower edges 311, 312, a bottom 313 and a flap closure 31 connected by a fold line 32 to one end front of the envelope opposite the bottom 313. The extender device, which is formed by the first and second sheets 10, 20, assembled, linked together by the elastic element of traction 301, and the sheet or leaflet 90 and card 91 are attached as described above in relation to the eleventh embodiment shown in Fig. 27, is sized to be inserted into the envelope 30 so that the edges upper and lower 165, 166; 265, 266 of the first and second sheets 10, 20 are a short distance from the upper edges and bottom 311, 312 of envelope 30. Thus, envelope 30 performs the functions of holding together the first and second sheets 10, 20 and guiding their relative movements

The first and second thrust regions 11, 21 of the first and second sheets 10, 20 are in this case about respective thrust edges 11, 21. The extender device is sized so that, when housed inside envelope 30 closed, the first and second sheets 10, 20 are in the situation contracted and the elastic tensile element 301 is tensioned to press the first pushing edge 11 against the bottom 313 of the over 30 and second pushing edge 21 against the fold line 32 of envelope 30. When a manual opening of the flap is started closure 31 (Fig. 29), the force of the elastic tensile element 301 move the second sheet 20 towards the extended position and causes automatically a complete opening of the closing flap 31 and an outlet of the second sheet 20 to a preeminent position. Thus, the second sheet 20 can be used as a support for the sheet or brochure 90 and card 91 to produce an effect surprising when a user starts the action of opening the envelope 30. It will be understood that, alternatively, sheet or booklet 90 and the card 91 could be omitted and the image or information could be printed directly on the second sheet 20, or a combination of both.

In Figs. 30 and 31 shows another example of applying a variant of the eleventh embodiment in cooperation with an envelope 30 to produce a surprising effect. In the application example of Figs. 30 and 31, the extender is also formed by first and second sheets 10, 20 linked by an elastic tensile element 301, and the main difference with respect to the extender device of the eleventh embodiment is that the rectangular shape of the first and second Blades 10, 20 is landscape here and that the second sheet 20 only includes a clamping tongue 269 and a pair of first clamping cuts 263, 264 to hold a sheet or booklet 90, without the card. Envelope 30 generally has the same characteristics as envelope 30 of Figs. 28 and 29, except that here it is a rectangular landscape in accordance with the first and second sheets 10, 20 of the device
expander

An example of application of the extender device of the first embodiment, although it could also be according to any other of the embodiments described above, where the folding structure expandable is a box 33 provided with a cover 34 connected to the box 33 by an articulation line 35. The first sheet 10 of the extender device has a first thrust edge (not shown in Fig. 32) embedded inside an edge 36 between the bottom and a side wall of the box 33 opposite said line of joint 35, and the second sheet 20 has a second edge of thrust 21 connected to an inner area of the cover 34 by means of, for example, a fin 37 attached by adhesive. The device extender is sized so that when it is inside the box 33 with the lid 34 closed, the first and second sheets 10, 20 they are in the contracted situation and the elastic elements of traction 301, 302 are stressed. When, for example, a latch device (not shown) that holds lid 34 closed is released, the strength of the elastic elements of traction 301, 302 moves the second sheet 20 towards the position extended and causes automatic opening of the lid 34.

In Figs. 33, 34 and 35 an example is shown of application of the extender device of the first embodiment, although it could also be according to any other of the embodiments described above, where the folding structure Expandable is a folding stand 50 for a support panel 51 of image or information, such as a photo frame. Said folding stand 50 is made, for example, of a piece of relatively rigid sheet material, such as cardboard or the like, and it comprises a leg 52, a connection portion 53 and the first and second sheets 10, 20 of the expander device. Leg 52 and connection portion 53 are articulated connected by a fold line 54, leg 52 and first sheet 10 are articulated connected by another fold line 55 that coincides with the first pushing edge 11, and the connecting portion 53 and the second sheet 20 are articulated connected by yet another fold line 56 that coincides with the second thrust edge 21. The connection portion 53 is glued to one side adhesive rear of panel 51 and the first and second sheets 10, 20 are assembled and linked together by one or more elastic elements of tension 301 as described above in relation to the first embodiment of the extender shown in Figs. one to 4. In a folded position as shown in Fig. 35, the first and second plates 10, 20 are in the contracted situation and elastic tensile elements 301 are tensioned. Starting of said folded position, the strength of the elastic elements of traction 301 moves the first and second sheets 10, 20 towards a extended position determined by limiter members Built-in expander device. This causes a deployment Automatic folding stand 50 by rotating the leg 52 around the fold line 54 to the deployed position of work shown in Figs. 33 and 34. From that position deployed work, manual pressure on panel 51 and the leg 52 allows folding the folding stand 50 against the force of the elastic tensile elements 301 again towards the position folded shown in Fig. 35.

Finally, in relation to Figs. 36, 37 and 38 describes a procedure that allows to manufacture exhibitors expandable folding quickly and economically, using digital printing. The procedure comprises first make by punching and marking cardboard pieces in white 60 (Fig. 36), each of which includes panels Layers 61, 62 for an expandable folding structure, with about outer contours, a few slits 63, 64 that define lines bending that delimit said laminar panels 61, 62, and optionally other cuts and / or clefts that define various configurations On at least one side of the cardboard piece in white 60 are formed one or more anchor points 65 die cut by which the expandable folding structure is held. These anchor points 65 are defined by slits 66 that surround a portion of material 67, which is attached to the rest of the blank cardboard piece 60 stamped only by a few points of union 68 that interrupt the slits 66. On the other hand, the procedure includes printing digital images and / or printing information on a relatively thin substrate sheet 70, and then adhering said substrate sheet 70 printed on the piece of blank cardboard 60, as shown in Fig. 37, to form a final piece 80 (Fig. 38).

Under the thinness of the substrate sheet 70 that carries digital printing, when the substrate sheet 70 is adhered to the blank cardboard piece 60 die cut, the cuts, slits 63, 64 and slits 66 of blank cardboard piece 60 are automatically marked on substrate sheet 70, of so that further die cutting operations are not necessary and marked on the final piece 80. Finally, the procedure comprises remove portions of material 67 from anchor points 65 of the final piece 80 formed by the blank cardboard piece 60 and the substrate sheet 70 joined, operation that can be performed Easy, fast and simple way by manually cracking the slits 66 marked in the final piece 80 with a knife or cutter 38 for cut the substrate sheet 70 and the attachment points 68 of the piece blank cardboard 60. Alternatively, the material portion 67 corresponding to anchor points 65 can be removed from the final piece 80 using a small manual die (not shown) in buffer form. After these operations, the structure Expandable folding display stand is ready to be assembled from The usual way.

An additional advantage of this procedure is that blank die cutting operations 60 can be carried out, for example, in a die-cutting workshop, to then the pieces of blank cardboard 60 stamped can be sent, in a flat unfolded situation, to a printing press digital where the digital printing of the sheets is made substrate 70, and the operations of joining substrate sheets 70 to the blank cardboard pieces 60 to form the final pieces 80 and of eliminating the portions of material 65 corresponding to the anchor points 65 of the end sheets 80 can be made comfortably in the same digital printing shop. So, the expandable folding structures can be manufactured so Fast and economical, using digital printing, and saving on all in transport costs, and die cut.

A person skilled in the art will be able to perform modifications and variations from the embodiments shown and described without departing from the scope of this invention as defined in the appended claims.

Claims (21)

1. Linear extender device, applicable to expandable or expandable folding structure, of the type comprising at least two sheets (10, 20) linked to each other by at least one elastic tensile element (301) and provided with respective regions of thrust (11, 21) capable of pressing internally against areas of said collapsible extendable or expandable structure by the force of said elastic tensile element (301) to extend or expand it, characterized in that it comprises: first and second sheets (10, 20), the which, in operational situation, are assembled so that they can slide guided one towards the other, where the mentioned first sheet (10) has at least a first anchor configuration (121) and a first thrust region (11) configured to be attached or in contact with an interior area of said expandable or expandable folding structure, and the second sheet (20) has at least a second anchor configuration (221) and a second push region (21) configured to be attached or in contact with another interior area of the folding structure extensible or expandable, being, in said operational situation, the mentioned first anchor configuration (121) of the first sheet (10) located closer to said second thrust region (21) of the second sheet (20) than said second anchor configuration (221) of the second sheet (20); Y at least one elastic tensile element (301) hooked on said first and second anchor configurations (121, 221) of the first and second sheets (10, 20), whereby the force of said elastic tensile element (301) slides the first and second plates (10, 20) the one with respect to the other in respective opposite directions of extension, in which the first and second thrust regions (11, 21) move away from one of the another, to automatically extend or expand the structure Extendable or expandable folding.

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2. Extender device according to claim 1, characterized in that the first thrust region (11) of the first blade (10) and the second thrust region (21) of the second blade (20) comprise respective first and second mutually opposite thrust edges (11, 21) configured to be in contact with said respective inner zones of the expandable or expandable folding structure, where the second anchor configuration (221) of the second sheet (20) will be located closer to the first thrust edge of the first sheet (10) than the first anchor configuration (121) of the first sheet (10). 3. An extender device according to claim 2, characterized in that it comprises sliding limiting means configured to limit the sliding of the first and second sheets (10, 20) by the force of the elastic tensile element (301) in a expanded position. 4. An extender device, according to claim 3, characterized in that said sliding limitation means comprise at least a first engagement configuration (131) formed in the first sheet (10) and located, in the operative situation, between the first and second anchor configurations (121, 221), such that said first engagement configuration (131) is engaged with said elastic tension element (301) when, when sliding the first and second sheets (10, 20) in opposite directions extension, the first hitch configuration (131) reaches the position of the second anchor configuration (221) of the second sheet (20), thereby canceling the tensile capacity of the elastic tension element (301) and limiting the sliding of the first and second sheets (10, 20) by the force of the elastic tensile element (301) in an expanded position. 5. An extender device according to claim 4, characterized in that the second sheet (20) has at least one second hook configuration (231) located, in the operative situation, between the second and first anchor configurations (221, 121), so that said second engagement configuration (231) is engaged with said elastic tension element (301) when, when sliding the first and second sheets (10, 20) in the opposite directions of extension, the second configuration of hitch (231) reaches the position of the first anchor configuration (121) of the first sheet (10). 6. Extender device according to claim 5, characterized in that the elastic tensile element (301) is in the form of an endless elastic band arranged surrounding the first and second anchor configurations (121, 221) and said first and second configurations of engagement (131, 231), the tensile elastic element (301) acting in cooperation with the first and second anchoring and engagement configurations (121, 221; 131, 231) additionally to hold the first and second sheets together (10, twenty). 7. Extender device according to claim 5, characterized in that the first sheet (10) has formed a first pair of first anchor and hook configurations (121, 131) and a second pair of first anchor and hook configurations (122 , 132) separated in parallel from the first pair, and the second sheet (20) has formed a first pair of second anchor and hook configurations (221, 231) and a second pair of second anchor and hook configurations (222, 232 ) separated in parallel from the first pair, at least some first and second elastic tension elements (301, 302) being provided in cooperation with said first and second pairs of first and second anchor and engagement configurations (121, 131; 221, 231; 122, 132; 222, 232).

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8. Extender device according to claim 7, characterized in that said first and second elastic tension elements (301, 302) are in the form of endless elastic bands and are arranged mutually parallel, with the first elastic tension element (301) surrounding the first pairs of first and second anchor and hitch configurations (121, 131; 221, 231) and the second elastic tensile element (302) surrounding the second pairs of first and second anchor and hitch configurations (122, 132; 222, 232), the first and second elastic tensile elements (301, 302) acting in cooperation with the first and second pairs of first and second anchor and engagement configurations (121, 131; 221, 231; 122, 132; 222 , 232) additionally to hold the first and second sheets (10, 20) together and guide the relative slides of the first and second sheets (10, 20) in opposite directions of extension and contraction tion. 9. Extender device according to claim 7, characterized in that said first and second elastic tensile elements (301, 302) are in the form of endless elastic bands and are mutually crossed, with the first elastic tensile element (301) hooked in the first anchor configuration (121) of the first pair of first anchor and hitch configurations (121, 131) and in the second anchor configuration (222) of the second pair of second anchor and hitch configurations (222, 232) and the second elastic tensile element (302) engaged in the first anchor configuration (122) of the second pair of first anchor and engagement configurations (122, 132)) and in the second anchor configuration (221) of the first pair of second anchor and hitch configurations (221, 231), the first and second elastic tension elements (301, 302) acting in cooperation with the first and second torque axes of first and second anchor and hitch configurations (121, 131; 221, 231; 122, 132; 222, 232) additionally to hold the first and second sheets (10, 20) together and guide the relative slides of the first and second sheets (10, 20) in the opposite directions of extension and contraction. 10. Extender device according to claim 7, 8 or 9, characterized in that the first and second pairs of first and second anchor and engagement configurations (121, 131; 221, 231; 122, 132; 222, 232) are formed on opposite outer edges of the first and second sheets (10, 20), respectively. 11. Extender device according to claim 7 or 8, characterized in that the first and second pairs of first and second anchor and engagement configurations (121, 131; 221, 231; 122, 132; 222, 232) are formed in opposite inner edges of first and second windows (151, 152; 251, 252) formed in the first and second sheets (10, 20), respectively. 12. Extending device according to any one of claims 1 to 6, characterized in that the first sheet (10) is bent at an angle by a first fold line (14) parallel to the opposite directions of extension and contraction, and the second sheet (20) is bent at an angle by a second fold line (24) aligned and superimposed on said first fold line (14), said first and second fold lines (14, 24) acting to guide the relative slides of the first and second sheets (10, 20) in the opposite directions of extension and contraction and to confer to the first and second sheets (10, 20) a greater compressive strength in a direction parallel to the opposite directions of extension and contraction . 13. Extender device according to claim 12, characterized in that the first and second anchor configurations (121, 221) are formed on rear edges of the first and second sheets (10, 20) and in alignment with the respective first and second fold lines (14, 24), and the elastic tensile element (301) is hooked to the second anchor configuration (221) of the second sheet (20) through a first elongated window (15) formed in the first sheet (10) in alignment with the first fold line (14) and the first anchor configuration (121) of the first sheet (10) through a second elongated window (25) formed in the second sheet (20 ) in alignment with the second fold line (24), the first and second engagement configurations (131, 231) being formed by internal edges of said first and second windows (15, 25), respectively. 14. Extending device according to claim 1, characterized in that the first pushing region (11) of the first sheet (10) comprises a portion intended to be glued internally to the corresponding area of the expandable or expandable folding structure, while that the second pushing region (21) of the second sheet (20) is a pushing edge (21) configured to be in contact with the corresponding internal area of the expandable or expandable folding structure. 15. Expandable folding structure, of the type comprising at least four laminar panels (41, 42, 43, 44) articulated jointly by their lateral edges so that it can adopt a flattened configuration, in which said laminar panels (41, 42, 43, 44) are parallel and totally or partially overlapping, and an expanded configuration, in which the laminar panels (41, 42, 43, 44) form a hollow body of polygonal cross-section, and at least one extender device including at least two sheets (10, 20) linked to each other by at least one elastic tensile element (301) and provided with respective thrust regions (11, 21) capable of pressing internally against areas of at least two of said panels laminar (41, 42, 43, 44) by the force of said elastic tensile element (301) to bring the expandable folding structure to said expanded configuration, characterized in that said extensor device comprises: first and second sheets (10, 20), the which, in operational situation, are assembled so that they can slide guided one towards the other, where the mentioned first sheet (10) has at least a first anchor configuration (121) and a first thrust edge (11) configured to be attached or in contact with an interior area of said expandable or expandable folding structure, and the second sheet (20) has at least a second anchor configuration (221) and a second pushing edge (21) configured to be joined or in contact with another interior area of the folding structure extensible or expandable, being, in said operational situation, the mentioned first anchor configuration (121) of the first blade (10) located closer to said second thrust edge (21) of the second sheet (20) than said second anchor configuration (221) of the second sheet (20), said second configuration anchor (221) of the second sheet (20) located closer to said first pushing edge (11) of the first sheet (10) that said first anchor configuration (121) of the first sheet (10); Y at least one elastic tensile element (301) hooked on said first and second anchor configurations (121, 221) of the first and second sheets (10, 20), whereby the force of said elastic tensile element (301) slides the first and second plates (10, 20) the one with respect to the other in respective opposite directions of extension, in which the first and second thrust edges (11, 21) move away from one of the other, to automatically extend or expand the structure Extendable or expandable folding.

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16. Structure according to claim 15, characterized in that it comprises sliding limiting means configured to limit the sliding of the first and second sheets (10, 20) by the force of the elastic tensile element (301) in a position expanded. 17. Structure according to claim 16, characterized in that said slip-limiting means comprise at least a first engagement configuration (131) formed in the first sheet (10) and located between the first and second anchor configurations (121, 221), so that said first engagement configuration (131) engages with said elastic tension element (301) when, when sliding the first and second sheets (10, 20) in the opposite directions of extension, the first configuration of coupling (131) reaches the position of the second anchoring configuration (221) of the second sheet (20), thereby canceling the tensile capacity of the elastic tensile element (301) and limiting the sliding of the first and second sheets ( 10, 20) by the force of the elastic tensile element (301) in the expanded configuration. 18. Structure according to claim 17, characterized in that two of said laminar panels are facing flat panels (41, 42) and the other two laminar panels are facing first and second folding panels (43, 44), each divided into two panel halves (43a, 43b; 44a, 44b) by a respective longitudinal fold line (45, 46), where the first pushing edge (11) of the first sheet (10) of the extender device is connected to one of said panel halves (43a, 43b) of the first folding panel (43) and the second pushing edge (21) of the second sheet (20) of the extender device is connected to one of said panel halves (44a, 44b ) of the second folding panel (44), so that the expandable folding structure can be brought to the expanded configuration by the force of the elastic tensile element (301) and can be manually forced to the configuration contracted against the force of the elastic element of traction (301). 19. Structure according to claim 18, characterized in that it includes a second extender device with the first pushing edge (11) of the first sheet (10) connected to the other of the panel halves (43a, 43b) of the first folding panel (43) and the second pushing edge (21) of the second sheet (20) connected to the other of the panel halves (44a, 44b) of the second folding panel (44). 20. Structure according to claim 19, characterized in that fins extending from the first and second thrust edges (11, 21) of the first and second sheets (10, 20) of the extender device are connected to the corresponding ones. panel halves (43a, 43b; 44a, 44b) by adhesive. 21. Structure according to any one of claims 17 to 20, characterized in that the laminar panels (41, 42, 43, 44) are crossed by transverse fold lines (48) perpendicular to edges formed between the laminar panels (41, 42, 43, 44) and mutually aligned, so that the expandable folding structure can be folded by said transverse fold lines (48) from said flattened configuration.