EP3519659B1 - Internal connection part for a sandwich structure and corresponding assembly method - Google Patents

Description

1. Domain

The field of the invention is that of door openings, also called leaves, and more particularly panel door openings. The invention also applies to partitions and panels for the construction of houses.

2. Prior art

In known manner, the panel openings incorporate a frame clamped between two panels, the latter defining with the frame a cavity into which an insulating material is injected. The frame is the result of the assembly of the uprights and cross members of the opening. Such an assembly can be implemented in different ways, depending in particular on the materials composing the uprights and cross members of the opening.

Thus, when the uprights and crosspieces are made of wood, it is known practice to produce a shoulder at the junction between the latter, then to join them together using screws or glue, as illustrated in FIG. la and 1b.

According to another known embodiment, the frame can also be made with metal profiles, generally aluminum, or with composite materials. In this context, the assembly of the profiles together is generally carried out by means of a screwed square, as illustrated by Fig. 2 .

Finally, when the uprights and cross members are made of a polymer material, such as polyvinyl chloride (PVC), assembly by welding is generally preferred, as illustrated by Fig. 3 .

The documents LU81479 , DE9109138U and DE20109011U describe sandwich structures for building elements of the prior art.

These various known embodiments have various drawbacks.

First, it has been observed that such assemblies exhibit unsatisfactory mechanical strength over time. Indeed, the mechanical stresses undergone by the frame tend to be concentrated at the level of the fastening systems, causing premature wear of the junction zones and consequently, of the entire frame. This phenomenon is particularly observed in assemblies by welding of PVC, given the rigidity of this material. Pressure from within of the cavity by the insulating material also tends to widen the junction areas, at the same time causing leaks through the frame.

Thus, such assemblies do not make it possible to implement a satisfactory partitioning between the cavity of the opening on the one hand and the outside of the frame on the other hand. In fact, taking into account the play existing between the various parts of the assembly and the generally hollow character of the profiles, in particular in assemblies of the metal against metal or composite against composite type, the insulating foam initially contained in the cavity tends to s 'escape from the frame, thereby causing aesthetic inconvenience and degradation of the thermal properties of the opening, the concentration of insulation within the cavity no longer being at its optimum threshold. In return, the humidity contained in the ambient air is caused to infiltrate within the cavity, further degrading the thermal properties of the opening. To remedy these drawbacks, it is known practice to apply a silicone seal at the junction zones. However, such a solution has the drawback of making the assembly process even more complex, while at the same time presenting risks relating to durability over time.

In addition, the methods used to produce such assemblies require the provision of specific assembly steps and require the use of specialized equipment.

For example, it is known to proceed with the welding of thermoplastic polymers by means of a heating mirror, ultrasound, a laser or a high frequency current. This mounting technique requires not only the use of suitable welding equipment, but also generally of a qualified operator, and can also impose constraints on the choice of the material of the profiles.

In the case of joining the adjacent profiles together by means of a fixing bracket, this process again requires a specific step during assembly, with several interventions calling for quality and precision of execution.

Other known assembly techniques have the drawback of being complex, time-consuming and / or of damaging the structure of the assembled parts.

There is therefore a need to alleviate these various drawbacks associated with manufacturing and assembly constraints, the risks of unsatisfactory sealing of the structure and the degradation over time of its mechanical and thermal performance and of its aesthetic appearance.

3. Summary

The proposed technique does not have these drawbacks of the prior art. More particularly, in at least one embodiment, the proposed technique relates to a sandwich structure according to claim 1 for a construction element comprising a quadrangular frame made up of two uprights and two cross members, the frame being covered by two panels added on each side. on the other side of said frame so that the internal surface of each of said panels closes a cavity defined between the four internal faces of the uprights and cross members, where said frame cooperates mechanically with at least one internal connecting piece of which a first face is in direct contact with the internal face of an upright and a second face is in direct contact with the internal face of a cross member adjacent to said upright.

The term “cavity” as used in the remainder of the description denotes a volume in the form of a rectangular parallelepiped, also called “core”, each of whose faces is closed off by one of the internal faces of the frame or of the panels. Advantageously, an insulating material can be injected into this cavity in order to improve the thermal properties of the sandwich structure. Obviously, openings can remain at the junctions between the various elements of the assembly, and are the source of several drawbacks which the present invention makes it possible to remedy.

In the remainder of the description, the terms “in direct contact” describe the mechanical connection established between two distinct parts of an assembly. According to certain embodiments, this direct contact can in particular be reduced to a support-plane connection, without any additional fixing device being implemented.

The invention is based on a new and inventive concept consisting in providing a non-complex connecting piece, included at least in part within the cavity, and which improves the watertightness of the structure at the targeted junction, as well as its mechanical behavior over time.

Thus, taking into account the positioning of this connecting piece inside the cavity, the mechanical stresses exerted on this connecting piece by the pressurized insulation material participate in maintaining the latter against the upright and the cross member of the frame. which are adjacent to it. The mechanical forces to be provided to hold the connecting piece in position are therefore reduced and the frame has better durability. The connecting piece also makes it possible to increase the shoulder surface between an upright and a cross member, and vice versa, while guaranteeing better squareness of the latter, i.e. a better right angle setting of the uprights and cross members. adjacent. Such a connecting part also makes it possible to facilitate the implementation of a shoulder between an upright and a cross member, in which the straightness between the external surfaces of these parts is satisfactory.

Advantageously, it is possible to vary the contact surfaces of the connecting part with the frame, as a function of the identified cohesion needs between these different parts.

Due to the improved cohesion between the connecting piece and the frame, such a connecting piece also provides better sealing to the structure, at the targeted junction. The risks of insulating material escaping out of the cavity, as well as moisture infiltration within the latter, are therefore reduced. Consequently, a sandwich structure according to the invention exhibits improved thermal properties, as well as better aesthetics.

According to a particular characteristic of the invention, the connecting piece is linked by at least one attachment to the internal face of said upright and / or to the internal face of said cross member.

The term “fastening”, equivalent to the terms “fastening system” and “intrinsic fastening” designates a device responding to the application of one or more techniques making it possible to make two or more parts of an assembly integral. Such a fastening can for example be in the form of a screw-nut connection, an elastic casing, also called clips, nailing, welding or gluing.

Advantageously, the connecting piece is both fixed to the internal face of the upright and to the internal face of the cross member, thus making it possible to increase the fixing capacity of the connecting piece to the frame.

According to one particular characteristic, said fixing is removable.

The implementation of a removable fixing makes it possible to facilitate the dismantling of the connecting piece, for example for the purposes of replacing or recycling the latter, independently of the rest of the structure. According to a particular embodiment, the fixing can be of the mechanical and / or electromagnetic type.

According to one particular characteristic, said fixing comprises at least one rounded assembly stud.

Such rounded studs allow a predetermined angular displacement between two parts during assembly. Consequently, these rounded studs make it easier to implement an assembly in a direction that is not strictly rectilinear.

According to one particular characteristic, said connecting piece comprises an external portion arranged in the extension of said upright and / or of said cross member.

In the following description, the arrangement of a first part "in the extension" of a second part denotes the positioning in direct contact of these first and second parts, so that the circumferential face of the first part has the same geometry. than the circumferential face of the second part, of which it is the extension. Such an arrangement allows in particular the extension, on the external portion of the connecting piece, of a connecting element formed on the circumferential surface of the frame, e.g. a groove adapted to cooperate with the J-fold of a panel. It is thus possible to increase the fixing surface of the panels on the frame. Even though the alignment of the circumferential surfaces, ie their straightness, is preferable, it is not strictly necessary.

According to a particular embodiment, this external portion of the connecting piece can be arranged in the extension of both the upright and a cross member. adjacent. Each of the circumferential faces of this outer portion then extends the circumferential face of an adjacent upright or cross member.

According to a particular embodiment, the connecting piece is in one piece.

The term “one-piece” as used in the description denotes an assembly formed from a single piece and not from a permanent or temporary assembly of mechanical parts. Such a single piece can be manufactured according to economic large-scale industrial processes and implemented at high rates, while exhibiting satisfactory resistance to mechanical stresses.

According to a particular embodiment, the connecting piece is embedded between said upright and said cross member.

Such a mechanical connection makes it possible to secure the connecting piece to the upright and crosses of the frame without necessarily implementing a fixing system.

According to a particular embodiment, the connecting piece comprises an exhaust channel in fluid communication with the cavity on the one hand and the exterior of the frame on the other hand.

The implementation of such an exhaust channel makes it possible to control, in particular by selecting a shape and / or a predetermined channel diameter, the exhaust flow rate of the air of the insulating material out of the cavity, in particular during the injection of the latter. According to a particular embodiment, such a “controlled partial sealing” allows the evacuation of the air during the filling of the cavity with insulating material, while limiting the escape of the latter once the air has been evacuated. . The controlled escape of the insulating material through the channel also makes it possible to ensure better sealing of the opening after solidification. Finally, the arrangement of this exhaust channel at a corner of the frame makes it possible to guarantee homogeneous filling of the cavity up to the ends of the corners, which the injection methods of the state of the art do not. not allow in an optimized and systematic way.

According to a particular embodiment, this exhaust channel is in the form of at least one groove or micro-channel formed on a contact surface between the connecting piece and the frame.

According to a particular embodiment, the sandwich structure comprises at least one cover arranged in the extension of said upright and / or of said cross member.

Such a cover makes it possible to strengthen the tightness of the frame while offering aesthetic comfort, since being part of the continuity of an upright and / or a cross member. When this cover is implemented in combination with an external portion of a connecting piece, these two elements can be secured to one another by means of a fastener.

According to a particular embodiment, said upright and / or said cross member consist of a hollow section.

The hollow sections have the advantage of being easy to manufacture, e.g. by extrusion, and of being light, while retaining satisfactory mechanical properties. According to particular embodiments, these hollow sections have one or more cavities closed or open to the outside, and are made of metallic, plastic, ceramic or composite materials.

According to the invention, said upright and / or said cross member have a groove cooperating with a J-shaped edge of one of said panels.

The implementation of one or more J-folds makes it possible to maintain an assembly in position by the set of elements "extrinsic" to the connecting and assembly parts of the uprights and crossbars between them, ie by the play of the folds J, grooves, L-folds, and not by "intrinsic" means, such as gluing or screw fixing.

According to a particular embodiment, the J-folds are implemented at the level of the circumferential surface of the uprights, which has the advantage of limiting as much as possible the deformation of the panels (greater at the level of the L-folds) on the part receiving the lock, where the opening / closing operation is essential.

However, the grooving of the frame is not necessarily limited to only the uprights. Thus, according to a particular embodiment, a frame comprises two uprights as well as a first cross member provided with a J-fold groove, the second cross member being held via an L-fold. According to another embodiment, two cross members include a groove, while at least one of the uprights is maintained via an L-fold.

The technique also relates to a door opening comprising such a sandwich structure.

Of course, all of the technical improvements which can be applied to the sandwich structure described above can also be applied mutatis mutandis to a door leaf implementing such a sandwich structure.

• l'apposition sur une surface plane d'un premier panneau comprenant un premier bord saillant en J et un second bord saillant opposé en J,
• le positionnement sur ledit premier panneau d'un châssis en forme de parallélogramme et comprenant deux montants et deux traverses respectivement agencés en opposition deux à deux, lesdits montants et/ou lesdites traverses comprenant chacun sur leur circonférence extérieure une rainure adaptée pour coopérer avec lesdits bords en J de sorte que ledit premier bord en J est enchâssé dans la rainure d'un desdits montants ou desdites traverses; au moins une pièce de liaison, comprenant une première face et une seconde face perpendiculaires entre elles, étant agencée à proximité de la jonction entre un montant et une traverse formant un angle obtus, de sorte que ladite première face est agencée en contact direct avec la face interne dudit montant ou de ladite traverse tandis que ladite seconde face est agencée en vis-à-vis dudit montant adjacent ou de ladite traverse adjacente,
• l'apposition sur ledit châssis d'un second panneau comprenant un premier bord en J et un second bord opposé en J de sorte que ledit premier bord en J est enchâssé dans ladite rainure,
• l'assujettissement dudit châssis à une forme rectangulaire par déplacement angulaire des montants et traverses adjacents, de sorte que lesdits seconds bords en J desdits premier et second panneaux sont enchâssés dans la rainure dudit montant opposé ou de ladite traverse opposée, et que ladite seconde face de ladite pièce de liaison est mise en contact direct avec ledit montant adjacent ou ladite traverse adjacente.

The technique also relates to a method of assembling a door leaf according to claim 15 comprising:

• affixing on a flat surface a first panel comprising a first protruding edge in J and a second protruding edge opposite in J,
• the positioning on said first panel of a frame in the form of a parallelogram and comprising two uprights and two cross members respectively arranged in opposition in pairs, said uprights and / or said cross members each comprising on their outer circumference a groove adapted to cooperate with said edges J so that said first J edge is embedded in the groove of one of said posts or cross members; at least one connecting piece, comprising a first face and a second face perpendicular to each other, being arranged near the junction between an upright and a cross member forming an obtuse angle, so that said first face is arranged in direct contact with the internal face of said upright or of said cross member while said second face is arranged facing said adjacent upright or said adjacent cross member,
• affixing on said frame a second panel comprising a first J edge and a second opposite J edge so that said first J edge is embedded in said groove,
• subjecting said frame to a rectangular shape by angular displacement of adjacent uprights and cross members, such that said second J edges of said first and second panels are embedded in the groove of said opposite post or said opposite cross member, and said second face of said connecting piece is brought into direct contact with said adjacent post or said adjacent cross member.

A method according to the invention thus makes it possible to assemble a door leaf in a non-complex manner, without necessarily having recourse to an intrinsic means of fixing the various components of the assembly to one another. By the set of extrinsic elements to the connecting and assembly parts of the uprights and cross members, ie by the play of J-folds, grooves, and possibly L-folds, the assembly is thus maintained in a fixed position and sustainable. Furthermore, such an assembly process does not require any specialized tooling and can therefore be implemented by any operator and anywhere.

4. Figures

• la figure la est un schéma illustrant l'assemblage par épaulement d'un montant et d'une traverse en bois, selon un procédé de l'état de la technique ;
• la figure 1b est un schéma illustrant l'assemblage par épaulement et vissage d'un montant et d'une traverse en bois, selon un procédé de l'état de la technique ;
• la figure 2 est un schéma illustrant l'assemblage au moyen d'une équerre vissée de deux profilés métalliques, selon un procédé de l'état de la technique ;
• la figure 3 est un schéma illustrant l'assemblage par soudure d'un châssis en polychlorure de vinyle, selon un procédé de l'état de la technique ;
• la figure 4 est un schéma illustrant la jonction entre un montant et une traverse adjacente d'un châssis, selon un premier mode de réalisation de l'invention ;
• la figure 5 est un schéma illustrant la jonction entre un montant et une traverse adjacente d'un châssis, selon un mode de réalisation particulier de l'invention ;
• la figure 6 est un schéma illustrant la jonction entre un montant et une traverse adjacente d'un châssis, selon un second mode de réalisation de l'invention ;
• la figure 7 est un logigramme illustrant les étapes successives mises en œuvre par un procédé d'assemblage d'un ouvrant de porte, selon un mode de réalisation particulier de l'invention ;
• les figures 8a et 8b illustrent des schémas d'un ouvrant de porte en cours d'assemblage, selon un mode de réalisation particulier de l'invention, respectivement dans une forme parallélépipédique provisoire et dans une forme rectangulaire définitive ;
• les figures 9 et 10 illustrent des coupes des liaisons montants/traverses avec les panneaux.

Other characteristics and advantages will become apparent on reading the following description of particular embodiments of the invention, given by way of simple illustrative and non-limiting examples, and the appended drawings, among which:

• FIG. la is a diagram illustrating the assembly by shoulder of an upright and a wooden cross member, according to a process of the state of the art;
• the figure 1b is a diagram illustrating the assembly by shoulder and screwing of an upright and a wooden cross member, according to a process of the state of the art;
• the figure 2 is a diagram illustrating the assembly by means of a screwed square of two metal profiles, according to a process of the state of the art;
• the figure 3 is a diagram illustrating the assembly by welding of a frame made of polyvinyl chloride, according to a process of the state of the art;
• the figure 4 is a diagram illustrating the junction between an upright and an adjacent cross member of a frame, according to a first embodiment of the invention;
• the figure 5 is a diagram illustrating the junction between an upright and an adjacent cross member of a frame, according to a particular embodiment of the invention;
• the figure 6 is a diagram illustrating the junction between an upright and an adjacent cross member of a frame, according to a second embodiment of the invention;
• the figure 7 is a flowchart illustrating the successive steps implemented by a method of assembling a door leaf, according to a particular embodiment of the invention;
• the figures 8a and 8b illustrate diagrams of a door leaf during assembly, according to a particular embodiment of the invention, respectively in a provisional parallelepiped shape and in a final rectangular shape;
• the figures 9 and 10 illustrate cross-sections of the upright / transom connections with the panels.

The various elements illustrated by the figures are not necessarily represented on a real scale, the emphasis being placed more on the representation of the general operation of the technique.

5. Detailed description of particular embodiments of the invention

The general principle of the invention is based on the implementation, within a sandwich structure and more particularly of a panel opening, of a connecting piece bearing at least in part on the respective internal faces of an upright and an adjacent cross member, of which this connecting piece closes the junction.

5.1 Assembly of a connecting part to the frame according to particular embodiments of the invention

The Fig. 4 illustrates the junction between an upright 1 and an adjacent cross member 2 of a frame 3, according to a first embodiment of the invention. The upright 1 comprises an internal face 1a, oriented towards the interior of the frame 3, an opposite circumferential face 1b and two transverse sections 1c, one of which is illustrated by the Fig. 4 . Likewise, the cross member comprises an internal face 2a, an opposite circumferential face 2b and two cross sections 2c, one of which is illustrated by Fig. 4 .

According to this first embodiment, the cross section 2c of the cross member is partly brought into abutment against the upper end (as shown in Fig. 4 ) on the inside of the upright 1.

A connecting piece 4 in the form of a rectangular parallelepiped is attached to the corner of the frame 3 formed at the junction between the upright 1 and the cross member 2. The first face 4a and the second face 4b of the connecting piece 4 are respectively fixed to the internal faces (1a; 1b) of the upright 1 and of the crosspiece 2. According to particular embodiments, such fasteners are of a mechanical nature and are in the form of a screw-nut connection, of an elastic fitting, nailing, welding, gluing or clipping of the connecting piece 4 in a dedicated groove made in the internal face of an adjacent section. According to another embodiment, the fixing is electromagnetic in nature and is carried out by means of magnets. The fastening can also be both magnetic and mechanical, the magnetic fastening helping the adequate positioning of the connecting piece while the mechanical fastening makes it possible to ensure a good hold of this fastening both in intensity and in time.

According to alternative embodiments, the connecting piece may have the shape of a triangular prism or any other shape comprising at least two perpendicular bearing faces. The materials used in the composition of the connecting piece can also vary depending on the constraints imposed on the manufacturer and the type of fixing envisaged.

Given the positioning of this connecting piece 4 inside the cavity 5, the mechanical stresses exerted on this connecting piece 4 by the pressurized insulation material participate in maintaining the latter against the uprights 1 and cross 2 of the frame 3. The mechanical forces to be provided to hold the connecting piece 4 in position are therefore reduced and the frame 3 has better durability over time.

Advantageously, it is possible to vary the contact surfaces (4a; 4b) of the connecting part 4 with the frame 3, according to the identified needs for cohesion between these different parts. Thus, the connecting piece 4 represented by the Fig. 5 has larger contact surfaces (4a; 4b), so as to facilitate the securing of the connecting piece 4 to the frame 3 and therefore its insulating power.

Due to the improved cohesion between the connecting piece and the frame, such a connecting piece also provides better sealing to the structure, at the targeted junction. The risks of insulating material escaping out of the cavity, as well as moisture infiltration within the latter, are therefore reduced. According to embodiments of the invention, seals are moreover added at the level of the fixing zones, so as to further strengthen the sealing of the assembly.

According to the first embodiment, a cover 6 in the form of a rectangular parallelepiped is also attached to the outer corner of the frame 3, in the extension of the upright 1 on the one hand and of the cross member 2 on the other hand. This cover 6 is thus fixed to the cross section 1c of the upright 1 on the one hand and to the cross section 2c of the cross member 2 on the other hand. The circumferential surfaces of this cover 6 have the same geometry as the circumferential faces of the cross member or of the adjacent upright.

Such a cover 6 makes it possible to strengthen the tightness of the frame 3 while offering improved aesthetics, since it is part of the extension of the upright 1 and of the cross member 2.

The Fig. 6 illustrates the junction between an upright 1 and an adjacent cross member 2 of a frame 3, according to a second embodiment of the invention, in which the upright 1 and the cross member 2 are not in direct contact.

A connecting piece 4 comprises an internal portion incorporating the technical characteristics of a connecting piece 4 according to the first embodiment described above, as well as an external portion 4 'arranged in the extension of the uprights 1 and transverse 2. This outer portion 4 'thus consists of an intermediate portion 4'a, embedded between the upright 1 and the cross member 2, and a circumferential portion 4'b providing a function similar to that provided by a cover 6 according to the first embodiment. achievement represented by the Fig. 4 .

According to an alternative embodiment not illustrated, a cover 6 separate from the connecting piece 4 replaces this circumferential portion 4'b.

The implementation of a connecting piece 4 comprising such an external portion 4 'has the advantage of not requiring the implementation of a fastening device with the frame 3. Indeed, the connecting piece 4 being embedded between the upright 1 and the cross member 2, this mechanical connection is sufficient to secure the connection of the connecting piece 4 to the frame 3.

In addition, the implementation of a one-piece connecting piece 4 comprising such an external portion 4 ′ makes it possible to limit the play that may exist between the components of the assembly, due to the different tolerance intervals. This assembly therefore has better sealing and better mechanical behavior over time.

As illustrated in more detail on figure 9 , the uprights 1 or the cross members 2 on opposite sides of the frame 3, are provided with a slot or groove 90a, 90b situated on the sides 1b, 2b of the uprights 1 or cross members 2 concerned defining the outer circumferential surface of the frame 3. The side panels 9a and 9b are provided on opposite edges with a substantially J-shaped flange 91a and 91b. This flange 91a, 91b comprises at its free end a flange 92a and 92b extending substantially parallel to the side panel 9a, 9b concerned and cooperating with the relevant slot or groove 90a, 90b of the frame 3 (the cooperation can be done by inserting the edge into the slot or groove or by applying the edge against the slot or groove).

As shown on the figure 10 , the facings 9a, 9b may have, on at least one of their edges not having a J-shaped rim, a substantially L-shaped rim 100a, 100b having a wing 101a, 101b extending substantially perpendicular to the panel 9a, 9b concerned and folded against the outer peripheral edge 1b, 2b of the upright 1 or crosspiece 2 concerned.

5.2 Method for assembling a door leaf according to a particular embodiment of the invention

The Fig. 7 is a flowchart representing the successive stages of assembly of a sandwich structure 7 and more particularly of a door leaf 8 according to one embodiment of the invention.

A first panel 9a is first affixed (step S1) on a flat surface. This panel 9a comprises two protruding edges in J 91a opposite to each other. In the example illustrated, the J-shaped edges are provided on the sides of the first panels 9a intended to cooperate with the uprights 1, 1 '.

Secondly, a frame 3 in the form of a parallelogram and comprising two uprights (1; 1 ') and two cross members (2; 2') respectively arranged in opposition in pairs, as illustrated by Fig. 8a , is positioned (step S2) on the first panel 9a. The uprights (1; 1 ') each comprise on their outer circumference a groove or slot 90a (not shown on figure 8a ) adapted to cooperate with the J edges 91a of the first panel 9a. The frame 3 is positioned so that a first J-edge 91a is embedded in the groove or slot 90a of a first post 1.

A connecting piece 4 is arranged near each of the corners of the frame 3 (interior angles), as illustrated by Fig. 8a . Thus, a first face 4a of each connecting piece 4 is fixed to the internal face 1a of an upright 1 while a second face 4b is arranged vis-à-vis the adjacent crosspiece 2.

A second panel 9b comprising two opposite J-edges 91b is subsequently affixed (step S3) to the frame 3 so that one of its J-edges 91b is embedded in the groove or slot 90b of the first upright 1.

Finally, the frame 3 is secured (step S4) to a rectangular shape by angular displacement of the adjacent uprights 1 and cross members 2, so that the non-embedded J-edges 91a, 91b of the first panel 9a and of the second panel 9b are embedded in the groove or slot 90a, 90b of the second upright 1 ', and that the second face 4b of each connecting piece 4 is brought into direct contact with the adjacent crosspiece 2. To do this, a thrust (arrows P) is exerted on one side of the frame 3 on one of the cross members 2, the frame 3 then passing from a parallelepiped shape to a rectangular shape by bringing the J edges not already embedded in a slot or groove to be housed there (cf. figure 8b ).

An assembly method according to the invention thus makes it possible to assemble a door leaf in a non-complex manner, without necessarily having to resort to specialized tools or to an intrinsic means of fixing the various components of the assembly to one another.

According to a particular embodiment, the assembly method comprises an additional step of forming L-folds 100a, 100b between the remaining edges of the panels 9a, 9b and the crossbars (2; 2 '). Such L-folds are formed by folding the edges of the panels 9a, 9b projecting on the crosspieces (2; 2 '). The formation of these L-folds thus makes it possible, in addition to the J-folds, to secure the panels 9a, 9b to the frame 3.

In the embodiment which has just been described, the J edges are provided on the sides of the panels intended to come into contact with the uprights. Alternatively, they could be provided on the sides of the panels intended to cooperate with the cross members. In this case, the grooves or slots are no longer provided in the uprights but in the cross members. The process steps described above are thus modified so as to allow the embedding of the J edges of the panels in the slots or grooves of the sleepers. In this case, the connecting pieces 4 are secured to the crosspieces rather than to the uprights.

In another variant, an L-fold is formed from the start at one end of each panel, the force to shape the frame into a rectangle then being oriented in the direction of the L-folds of the panels. In the example shown in figure 8a , an L-fold would thus be formed at the end of each panel located on the side of the crosspiece 2 '. During the deformation of the frame, the cross member 2 'would then be brought into abutment against the L-shaped edges. A second L-shaped edge could then be provided on the other side of each panel.

In case the J edges are formed on the side of the sleepers, the L edges are formed on the side of the studs.

Claims (16)

1. Sandwich structure (7) for a construction element comprising:

   • a quadrangular frame (3) consisting of two uprights (1; 1') and two crosspieces (2; 2'),

   • two panels (9) attached to either side of said frame (3) and covering the same so that the inner surface of each of said panels closes a cavity (5) defined between the four inner faces (1a; 2a) of the uprights (1; 1') and crosspiece (2; 2'), said panels each comprising two opposing protruding J-edges cooperating with grooves provided in said uprights or in said crosspieces, in order to secure said panels to said frame

   where said frame (3) mechanically cooperates with at least one inner connection part (4), a first face (4a) of which is in direct contact with the inner face (1a) of an upright (1) and a second face (4b) is in direct contact with the inner face (2a) of a crosspiece (2) adjacent to said upright (1).
2. Sandwich structure (7) according to claim 1, characterised in that said connection part (4) is connected by at least one attachment to the internal face (1a) of said upright (1) and/or to the internal face (2a) of said crosspiece (2).
3. Sandwich structure (7) according to claim 2, characterised in that said attachment is removable.
4. Sandwich structure (7) according to either of claims 2 and 3, characterised in that said attachment comprises at least one rounded assembly stud.
5. Sandwich structure (7) according to any one of claims 1 to 4, characterised in that said connection part (4) comprises an external portion (4') arranged in the extension of said upright (1) and/or said crosspiece (2).
6. Sandwich structure (7) according to any one of claims 1 to 5, characterised in that said connection part (4) is one-piece.
7. Sandwich structure (7) according to any one of claims 1 to 6, characterised in that said connection part (4) is embedded between said upright (1) and said crosspiece (2).
8. Sandwich structure (7) according to any one of claims 1 to 7, characterised in that said connection part (4) comprises an exhaust channel in fluid communication with the cavity (5) on the one hand and the outside of the frame (3) on the other hand.
9. Sandwich structure (7) according to claim 8, in which said exhaust channel is in the form of at least one ridge or microgroove provided on a contact surface between the connection part and the frame.
10. Sandwich structure (7) according to claim 8 or 9 in which said exhaust channel is arranged in a corner of said frame.
11. Sandwich structure (7) according to any one of claims 1 to 10, characterised in that it comprises at least one cover (6) arranged in the extension of said upright (1) and/or of said crosspiece (2).
12. Sandwich structure (7) according to any one of claims 1 to 11, characterised in that said upright (1) and/or said crosspiece (2) consist of a hollow profile.
13. Sandwich structure (7) according to any one of claims 1 to 12, characterised in that the remaining edges of said panels (9) have L-shaped folds ensuring, in addition to said J-edges, the securing of said panels (9) to said frame (3)
14. Door leaf (8) comprises a sandwich structure (7) according to any one of the preceding claims.
15. Method for assembling a door leaf (8) comprising:

    • the affixing (S1) on a planar surface of a first panel (9a) comprising a first protruding J-edge and a second opposing protruding J-edge;

    • the positioning (S2) on said first panel (9a) of a frame (3) in the form of a parallelogram and comprising two uprights (1; 1') and two crosspieces (2; 2') respectively arranged side by side in opposition, said uprights (1; 1') and/or said crosspieces (2; 2') each comprising on their outer circumference a groove adapted to cooperate with said J-shaped edges so that said first J-edge is embedded in the groove of one of said uprights (1; 1') or said crosspieces, at least one connecting piece (4), comprising a first face (4a) and a second face (4b) perpendicular to each other, being arranged close to the junction between an upright (1) and a crosspiece (2) forming an obtuse angle such that said first face (4a) is arranged in direct contact with the internal face (1a) of said upright (1) or of said crosspiece (2) while said second face (4b) is arranged opposite said adjacent upright (1) or said adjacent crosspiece (2),

    • the affixing (S3) on said frame (3) of a second panel comprising a first J-edge and a second opposing J-edge such that said first J-edge is embedded in said groove,

    • securing (S4) of said frame (3) to a rectangular shape by angular displacement of adjacent uprights (1; 1') and crosspieces (2; 2'), so that said second J-edges of said first and second panels (9) are embedded in the groove of said opposite upright (1') or said opposite crosspiece (2'), and said second face (4b) of said connecting piece (4) is brought into direct contact with said adjacent upright (1) or said adjacent crosspiece (2).
16. Assembly method according to claim 15 comprising an additional step of forming L-shaped folds at the remaining edges of the panels (9) allowing, in addition to said J-edges, to secure said panels (9) to said frame (3).

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