METHOD FOR MANUFACTURING A STRUCTURAL ELEMENT WITH PRE-PRESSED PLATES

Description

[0001] The present invention relates to the field of construction systems intended for the construction of wooden elements such as dwellings or small collectives.

[0002] Various techniques are already known for designing and manufacturing construction systems from wooden construction elements.

[0003] By "constructive element" we mean any type of element likely to equip a construction system, whether load-bearing or not, for example, but not limited to, a panel, a partition, a post, a beam or even a window.

[0004] FR2737745A3, which shows the preamble of claim 1, discloses an industrialized construction using assemblies capable of transmitting significant forces in structures and relates to a method for coplanar assembly of timber frame parts. US1289147A discloses a locking plate for bolted connections, in which the locking plate is interposed between timber beams around the bolt, in order to lock the timber beams together. WO2018065729A1 discloses a construction system and method comprising the use of a set of constituent elements, at least one of which comprises at least two superimposed plies each comprising at least two structural timber slats. FR3056997A1 discloses a construction system and method comprising the use of a set of constituent elements, at least one of which comprises at least two superimposed plies each comprising at least two structural timber slats.

[0005] According to one of the known techniques, a constructive element can be formed from a set of folds (or layers) superimposed on each other.

[0006] In a first configuration, each ply comprises a structural wooden blade - or a plurality of structural wooden blades parallel to each other - and the successive plies rest on each other.

[0007] In a second configuration, called "CLT" or "Cross Laminated Timber" (or, in English, "Cross Laminated Timber"), in each ply, the structural wooden slats are arranged one after the other and are parallel to each other. In addition, the plies are arranged, relative to each other, so that the slats of one ply are orthogonal to the slats of an adjacent ply.

[0008] In each of these configurations, the structural blades of a first ply are juxtaposed with the structural blades of a second ply, adjacent to the first ply, and are held against each other. In this configuration, a face of a blade of the first ply and a face of a blade of the second ply are thus in contact at a plane forming a contact interface.

[0009] In order to improve the locking of the structural blades in the plane of the contact interface, it is also known to arrange on the faces of the structural blades thus in contact a set of patterns, for example grooved patterns. These patterns can be arranged in such a way that the respective patterns of the faces of the blades in contact cooperate and prevent these blades from sliding relative to each other in the plane of their contact interface. This locking is all the better in the case where the grooved patterns have at least substantially complementary shapes.

[0010] In this latter configuration, it is important to hold the structural blades of the adjacent folds against each other along the axis orthogonal to the plane of the blades (which is also the plane of the contact interface between the blades) by means of one or more holding systems.

[0011] One of the main challenges of this system is not only to keep the structural blades against each other as well as possible but also to allow good transmission and recovery of the forces transmitted by the blades by applying a compression force locally on the assembly.

[0012] In this context, we speak of a "local compression" force to designate a force which is exerted along the axis orthogonal to the plane of the blades, as well as a "shear" force to designate a force which is exerted in the plane of the blades (which is also the plane of the contact interface between the blades).

[0013] The absorption - or transmission - of forces from one blade to another ensures high mechanical resistance to the assembly and combats the natural movement of the grooved patterns which separates the blades from each other. It is therefore desirable that the holding system allows such a transmission of forces.

[0014] Furthermore, even if the grooved patterns are complementary, in practice they never fit together perfectly and therefore generally cause a space to appear between the blades at the contact interface, which is unfavorable to the absorption of frictional forces on the surfaces of the grooved patterns.

[0015] A first known holding system consists of a layer of glue at the contact interface. However, glue has several disadvantages. First, its ecological impact is particularly harmful, and it is therefore advisable to limit the quantity of glue used. Second, glue does not promote industrialization, particularly since it requires long pressing and drying times. Third, glue can be detrimental from the point of view of seismic resistance, because glued assemblies have no plasticity and will therefore break suddenly in the event of excessive stress.

[0016] Alternatively, glue-free holding systems are also known. A first category of non-adhesive systems includes pin, ring, or stud-type devices and spike or staple-type devices. However, the geometry of these devices does not provide strong resistance to tearing to combat the traction induced between the holding systems and the wood of the boards due to the natural sliding of the grooved patterns.

[0017] A second category of non-adhesive systems includes rod-type components with threads, including bolts and screws. However, bolts are unsuitable for industrial production, as they require a pre-drilling step and space for the nut. In addition, they involve play around their body, which only allows tensile forces to be absorbed at the nut location.

[0018] In particular, no known holding system truly takes into account the grooved patterns to allow suitable transmission of forces between two superimposed structural slats. The object of the present invention is therefore, in a constructive element composed of superimposed wooden structural slats and provided with grooved patterns, to improve the transmission of forces between the slats and therefore to improve the mechanical resistance of the constructive element thus composed.

[0019] To this end, a constructive element is provided according to an unclaimed example. The constructive element comprises at least two structural wooden blades arranged such that one face of the first blade and one face of the second blade are superimposed at a contact interface, the superimposed faces being at least partially provided with a set of grooved patterns at the contact interface, the patterns having at least substantially complementary shapes and being arranged so as to prevent the first blade and the second blade from sliding relative to each other along at least one axis, and at least one holding system arranged so as to hold at least two blades against each other at the contact interface.According to the example, the grooved patterns of the superimposed faces are previously pressed against each other, and the holding system comprises at least one metal threaded rod member passing - at least partially - through at least two of the wooden structural blades at the contact interface.

[0020] Thanks to the configuration of the constructive element, the grooved patterns are pressed against each other before being held together by the holding system. This preliminary support allows the grooved patterns to fit together more precisely and improves the transmission of forces and the mechanical resistance of the assembly. In addition, when the pressure previously applied to the blades exceeds a certain threshold, the grooved patterns can be slightly deformed, which also contributes to the contact and cooperation of the grooved patterns and, in so doing, to the transmission of forces. In addition, this preliminary contact allows the blades to be positioned relative to each other with greater precision before holding them together, which further improves the cooperation of the blades and the grooved patterns with each other.

[0021] In addition, the example allows for other advantages brought by, among others, the metal threaded rod members, in particular their speed of penetration into the wooden structural blades, as well as the high resistance to tearing in the wood from which these members benefit. The maintenance can therefore be ensured more easily, with higher reliability and minimizing the risk of splitting the wood.

[0022] Furthermore, the example allows the use of grooved patterns to be taken advantage of by avoiding the use of glue at the contact interface. The constructive element thus formed therefore avoids the use of glue - or at least uses little - glue. It follows that all of the aforementioned problems related to glue can be overcome. Furthermore, by favoring an assembly by grooved patterns, the example makes the use of hardwood wood advantageous for forming the structural blades. Indeed, wood is generally classified into two categories: softwood and hardwood. Softwood is generally preferred to hardwood for its lower price and ease of drying in the field of construction. Hardwood wood has a greater density.Since the quality and wearability of grooved patterns is directly related to the density and local mechanical strength of the wood fiber, this is facilitated with hardwood, regardless of the visual appearance and quality of the original wood.

[0023] In the method according to the invention, the grooved patterns are arranged so as to prevent the first blade and the second blade from sliding relative to each other along at least two non-parallel axes. Locking is thus ensured throughout the plane of the contact interface.

[0024] Preferably, the grooved patterns comprise a first series of grooves parallel to each other, and a second series of grooves parallel to each other but not parallel to the grooves of the first series. The grooved patterns are then in the form of points (the ends of which may or may not be pointed depending, in particular, on the industrialization conditions).

[0025] More preferably, at least a portion of the grooved patterns has the shape of a matrix of pins, the shapes of which are substantially those of a pyramid with a quadrilateral base. This shape of patterns proves easier to machine.

[0026] In a particular embodiment, the member comprises a threaded rod provided with a head and a point, arranged at opposite ends of the rod.

[0027] This head is larger than the diameter of the screw body, its dimension results from a compromise between a small dimension to ruin as few grooved patterns as possible and a sufficient dimension to create a standard imprint allowing sufficient coupling at the time of insertion. Indeed when the screw is inserted, the imprint undergoes a certain torque (or force) which will allow it to penetrate the material. The shape of this imprint is the TORX standard, linked to the diameter of the head; it is selected to correspond to the necessary torque but also to reduce the risk of ejection of the tool when inserting the screw. The point allows a pre-drilling effect ("self-drilling" screw) and reduces the risk of splitting the wood during insertion.

[0028] Preferably, the member has a generally cylindrical shape.

[0029] In a preferred embodiment, the shank of the member comprises at least two interlocking threads of different diameters. The classic characteristics of a thread are its pitch and its diameter. The larger the pitch of the thread, the higher the speed of penetration into the wood. The larger the diameter of the thread, the more it causes the wood to work locally in shear. Therefore, by providing two threads of different diameters, the wood is worked locally in two different shear planes, which has the effect of reinforcing the mechanical strength of the assembly and reducing the penetration time of the screw by the size of the screw pitch linked to the existence of the two threads.

[0030] Preferably, the ratio of the diameter of the largest thread to the diameter of the shank is between 1.5 and 1.7. This ratio has been identified as particularly suitable for the use of hardwood blades.

[0031] Preferably, the holding system comprises four metal threaded rod members distributed over the entire contact interface and passing at least partially through at least two of said wooden structural blades at the contact interface, which makes it possible to cover as much of the surface area of ​​the contact interface as possible with a minimum number of members (the greater the number of members passing through the grooved patterns, the fewer grooved patterns remain to ensure blocking in the plane of the contact interface).

[0032] In one embodiment, the distance separating at least one of the threaded rod members from the edge of the contact interface is between 1.5 and 4 centimeters. The holding system in question is thus placed on the peripheral part of the contact interface, that is to say at the location where the forces are greatest when the assembly undergoes a moment and so as to firmly press the entire surface.

[0033] In the case where the constructive element resulting from the method according to the invention comprises at least three structural wooden blades, at least some of the faces of which are superimposed two by two at respective contact interfaces, preferably, the holding system comprises a first set of members with a metal threaded rod passing at least partially through a first part of the blades and a second set of members with a metal threaded rod passing at least partially through a second part of the blades, the first and second parts of the blades having at least one blade in common, the members being offset from each other in the planes of the contact interfaces of the blades. This configuration makes it possible to avoid a single member having to pass through the thickness of all the blades, which would require increasing the diameter of the members and reducing the precision of the assembly.Since the members pass through two thicknesses, it is necessary to avoid collision between the members. Furthermore, for reasons of symmetry, the positioning of the second member is identical to that of the first member after a 90° rotation relative to the center of the holding system. This configuration makes it possible to pass through the entire thickness of the constructive element by overlapping a set of members for three or more blades, taking into account the dimensions of the members. In addition, the length of at least one of the members with a metal threaded rod is substantially equal to the cumulative thickness of the part of the blades that it is intended to hold together. Therefore, the rod and the thread penetrate the blades over their entire thickness, which increases the proportion of stressed material and improves the resistance to tearing of the rod in the wood and therefore the maintenance of the prestressing of the grooved patterns.

[0034] Preferably, at least one of the metal threaded rod members is positioned in a recess of the grooved patterns (i.e., at the lower end that surrounds each pattern and connects the patterns together), thereby facilitating penetration of the member.

[0035] In the method according to the invention, the grooved patterns of the superimposed faces are previously pressed against each other with a pressure of at least 75 kPa.

[0036] The example further proposes to improve the arrangement of the holding system(s) with respect to the structural blades. In this context, the diameter of at least one of the members is configured to cover at most four grooved patterns. The system thus damages the fewest possible grooved patterns.

[0037] The present invention relates to a method of manufacturing a constructive element as described above, which is provided according to claim 1.

[0038] In this manufacturing process, prior to their superposition, the faces of the structural blades intended to be superimposed are machined in such a way as to provide them with grooved patterns.

[0039] A construction system comprising at least two construction elements, at least one of which is as described above, is provided according to a second unclaimed example.

[0040] Other characteristics and advantages of the invention will appear on reading the following description of embodiments of the invention, given by way of example and with reference to the appended drawings.

[0041] There figure 1 is a perspective view of an example of a construction system according to the present invention.

[0042] There figure 2 is a perspective view of one of the constituent elements of the construction system of the figure 1 , according to the present invention.

[0043] THE figures 3 et 4 are perspective views of two structural blades of a constructive element, according to a first embodiment of the present invention.

[0044] THE figures 5 et 6 are perspective views of two structural blades of a constructive element, according to a second embodiment of the present invention.

[0045] THE figures 7 et 8 are sectional views of three structural blades of a constructive element, according to a third embodiment of the present invention.

[0046] There figure 9 is a top view of a contact interface between two blades.

[0047] THE figures 10A et 10B are close-up views of the interface of the figure 9 .

[0048] There figure 1 is a perspective view of an example of a construction system with elements manufactured by the method according to the present invention.

[0049] There figure 2 is a perspective view of one of the constituent elements of the construction system of the figure 1 , manufactured by the method according to the present invention.

[0050] THE figures 3 et 4 are perspective views of two structural blades of a constructive element, according to a first embodiment of the method of the present invention.

[0051] THE figures 5 et 6 are perspective views of two structural blades of a constructive element, according to a second embodiment of the method of the present invention.

[0052] THE figures 7 et 8 are sectional views of three structural blades of a constructive element, according to a third embodiment of the method of the present invention.

[0053] There figure 9 is a top view of a contact interface between two blades.

[0054] THE figures 10A et 10B are close-up views of the interface of the figure 9 .

[0055] THE figures 11A et 11B are respectively a side view and a top view of a member of a holding system according to an embodiment of the method of the invention.

[0056] There figure 12 is a detailed sectional view of a constructive element according to an embodiment of the method of the present invention.

[0057] In reference to the figure 1 , a construction system 1 manufactured according to the method of the present invention may be in the form of a wooden dwelling, although any other form of building may be envisaged. This dwelling comprises in particular a floor, walls and a roof slope. They may for example be made of wood. Openings may be made in several of these elements, for example on one of the walls in order to affix a window there.

[0058] In this example, a first wall comprises a set of construction elements including construction element 10. A second wall itself comprises a set of construction elements including element 20. This division into construction elements is due to the sizing limits of standard transport, lifting means in construction and industrial tools for manufacturing these elements.

[0059] The constructive element 10 is shown in more detail on the figure 2 . The first constructive element 10 of the figure 2 comprises a set of eight superimposed plies, the first four of which are plies 100, 110, 120 and 130. The configuration of the plies is called “cross-blade”. A different number of plies may be provided, for example greater than three, preferably between five and fifteen, preferably between seven and twelve. Determining the optimal number of plies is a trade-off between the thermal performance of the construction element 10, its strength (the better the more plies there are), its overall thickness (which, usually, must not exceed a certain limit), its cost and its application (interior, exterior walls, floors or slopes, etc.).

[0060] Each of the plies 100, 110, 120 and 130 comprises structural wooden slats. The first ply 100 comprises four slats 101, 103, 105 and 107 parallel and oriented along the axis (Ox). The second ply 110 comprises four slats 111, 113, 115 and 117 parallel and oriented along the axis (Oy). The third ply 120 comprises four slats parallel and oriented along the axis (Ox). The fourth ply 130 comprises four slats parallel and oriented along the axis (Oy). In this “cross-slat” configuration; the plies 100, 110, 120 and 130 are made up alternately of slats parallel along the axis (Ox) and slats parallel along the axis (Oy). The structural blades of two adjacent plies are orthogonal to each other and together form a grid covering the entire constructive element 10.

[0061] The blades of the same ply may be oriented in the same direction and are spaced from each other so as to cover the entire constructive element 10 in a substantially uniform manner. These blades are oriented so that the blades of one ply are orthogonal to the blades of an adjacent ply, but a different angle could also be provided between these blades. Furthermore, the number of structural blades for each ply results from a trade-off between saving wood, on the one hand, and the solidity and size of the constructive element, on the other hand.

[0062] A functional blade (not shown) can be inserted between two structural blades of the same ply. This functional blade is intended to fulfill a specific function, different from that of the structural blades, in other words it is not used to support the constructive element and is not made of solid wood (but it can be made of certain types of insulation, such as wood wool, which are not recognized as having load-bearing properties). The choice of its constituent material depends on the function that one wishes to give it. This function can relate to thermal and / or acoustic insulation, thermal inertia, fire resistance or any other function considered appropriate. In addition, saving wood requires supplementing the absence of material of the structural blades with functional blades and further improves the associated capacity.

[0063] As can be seen more precisely on the figure 3 , the structural blade 101 has in particular two faces 101A and 101B. The structural blade 111 also has in particular two faces, one of which is referenced 111B. When the folds 100 and 110 are superimposed on each other, the structural blades 101 (shown in white) and 111 (grooved) come into contact at their respective faces 101A and 111B, which form a contact interface I 101-111 located in the plane (Oxy).

[0064] THE figures 3 et 4 represent more precisely the contact between two structural blades 101 and 111 of two adjacent plies 100 and 110, according to a first embodiment of the method of the present invention.

[0065] On the figure 3 , the structural blade 101 has a lower face 101A (not visible) and an upper face 101B. Similarly, the structural blade 111 has a lower face 111A (not visible) and an upper face 111B. When the plies 100 and 110 are superimposed, the structural blades 101 and 111 come into contact at a contact interface I 101-111 located in the plane (Oxy).

[0066] As can be seen on the figure 4 , the lower face 111B of the blade 111 is provided with a set of grooved patterns R 111B , over its entire longitudinal extent, that is to say along the axis (Oy). The upper face 101A of the blade 101 is also provided with a set of grooved patterns R 101A , but only over a part of its longitudinal extent, along the axis (Oy). On the faces 101A and 111B, the grooved patterns R 101A and R 111B are complementary and form a series of rectilinear grooves parallel to each other. These patterns are arranged on the faces of the blades so as to cover the contact interface I 101-111 . Their shapes and dimensions are substantially identical, so that these grooved patterns are substantially complementary to each other.

[0067] Thus, when the blades 101 and 111 are superimposed on each other, the grooved patterns R 101A and R 111B fit at least partially into each other, which makes it possible to prevent the two blades 101 and 111 from sliding relative to each other along a first blocking axis B 1 , parallel to the axis (Oy), orthogonal to the axis of the grooves (Ox), in the plane (Oxy) of the contact interface I 101-111 . This obstacle is obtained without having the glue at the contact interface I 101-111 , thus avoiding the disadvantages of the glue, in particular from an ecological, mechanical and industrial point of view. Furthermore, these grooved patterns can serve as markers for fitting the blades together, in particular in the context of automated assembly.

[0068] In this example, the grooved patterns have a triangular cross-section, but other grooved pattern shapes are possible, including non-triangular cross-section shapes. For example, a square, rectangular, or semicircular cross-section can be provided.

[0069] In order for the grooved patterns R 101A and R 111B to remain less partially nested in each other, at least one holding system is provided to hold the blades against each other at the contact interface. In the example of the figures 3 et 4 , the holding system comprises two members 30.1 and 30.2, distributed at the contact interface I 101-111 , in the form of a metal threaded rod which will be described in more detail below. The holding system thus does not include glue, always in order to avoid - or at least limit - the quantity of glue present in the constructive element 10. This holding system ensures that the blades 101 and 111 are held against each other along the axis (Oz) orthogonal to the plane (Oxy) of the contact interface I 101-111 . Metal threaded rods have several advantages, including speed of penetration and resistance to tearing in the wood. The holding can therefore be ensured more easily, with higher reliability and minimizing the risk of splitting the wood.

[0070] THE figures 5 et 6 more precisely represent the contact between two structural blades 101 and 111 of two adjacent plies 100 and 110, according to a second embodiment of the method of the present invention.

[0071] On the figure 5 , it can be seen that the general structure and superposition of the structural blades 101 and 111 are similar to those of the figure 3 .

[0072] On the figure 6 , it can be seen more precisely that the face 111B of the blade 111 is provided, on the one hand, with the grooved patterns R 111B ", in the form of parallel grooves arranged over the entire longitudinal extent of the blade, along the axis (Ox), and on the other hand with additional grooved patterns R 111B ', in the form of parallel grooves arranged only over a part of the transverse and longitudinal extent of the blade 111, along the axis (Oy), that is to say orthogonal to the grooves R 111B ''. Conversely, the face 101A of the blade 101 is provided, on the one hand with the grooved patterns R 101A ', in the form of parallel grooves arranged only over a part of the longitudinal extent of the blade 101, along the axis (Ox), and on the other hand with additional grooved patterns R 101A'', in the form of parallel grooves arranged over the entire longitudinal extent of the blade, along the axis (Oy), i.e. orthogonal to the grooves R 101A'.

[0073] In this configuration, the grooved patterns R 101A ', R 101A '', R 111B ' and R 111B " are arranged so as to prevent the first blade and the second blade from sliding relative to each other along two non-parallel blocking axes B 1 and B 2 located in the plane (Oxy) of the contact interface I 101-111: the first blocking axis B 1 , parallel to the axis (Ox), orthogonal to the grooves R 111A ' and R 111B ", and the second blocking axis B 2 , parallel to the axis (Oy), orthogonal to the grooves R 111A '' and R 111B '. The obstacle to the sliding of the blades 101 and 111 relative to each other is thus obtained in the entire plane of the contact interface I 101-111, without requiring glue.

[0074] In this configuration, the part of the contact interface I 101-111 which comprises the grooved patterns R 101A ', R 101A '', R 111B ' and R 111B " is in the form of points P 101A and P 111B , the ends of which may or may not be pointed depending on the circumstances, in particular depending on the industrialization conditions. On the figure 6 , we observe that these points form a matrix of pins whose shape is substantially that of a pyramid with a quadrilateral base, in particular a square base. This pin shape proves to be easier to machine. It will be understood that other shapes of patterns are possible, for example with a triangular base, or even with a parallelogram base, in particular in the case where the axes of the grooves are not orthogonal.

[0075] On the figure 5 , we see that the blades are held together along the axis (Oz) by a holding system comprising four members 30.1, 30.2, 30.3 and 30.4, all in the form of metal threaded rods. A different number and distribution of these members is nevertheless possible.

[0076] It will be understood that to ensure locking of the blades 101 and 111, it is sufficient that the grooved patterns R 101A ", R 101A '', R 111B ' and R 111B " are arranged on at least a part of the contact interface I 101-111 . Nevertheless, from a mechanical point of view, the locking of the blades will be all the better if the faces are provided with grooved patterns over the entire contact interface I 101-111 . Furthermore, from an industrial point of view, the grooved patterns can be produced by machining the faces 101A and 111B. In this case, the machining can be carried out more easily, cleanly and quickly over the entire length of the blades, rather than only over a part of them.

[0077] In the above examples, the blades 101 and 111 are orthogonal to each other and the locking axes B 1 and B 2 are themselves orthogonal. Other examples may be provided in which the blades 101 and 111 are not orthogonal but inclined relative to each other, for example at an angle close to 45°. The invention more generally covers any possible inclination between two structural blades.

[0078] In order to strengthen the mechanical connection between the grooved patterns of the blades 101 and 111, these are made of hardwood. This type of wood has a greater density, which makes the grooved patterns - small in size and therefore potentially fragile - stronger and less likely to be torn off under the effect of mechanical stress. In addition, since the strength of the assembly has been improved, the invention makes it possible to use hardwood with smaller sections and lower quality, which not only allows savings when purchasing the raw material, but also a revaluation of these woods usually intended to be burned to produce energy.

[0079] According to the present invention, before being held together by the members 30.1 to 30.4, the grooved patterns R 101A ', R 101A '', R 111B ' and R 111B " are first pressed against each other. This preliminary pressure can be ensured by various means within the reach of those skilled in the art, for example by applying a weight to the upper blade. In the particular context of blades with grooved patterns, this makes it possible to fit the grooved patterns more precisely into each other before the application of the members, which improves the precision of the assembly. The transmission of forces and the mechanical strength of the assembly are also improved due to this preliminary pressure. The pressure used according to the invention to carry out this pressurization of the blades is equal to or greater than 75 kPa.For example, with a square contact interface measuring 12 centimeters by 12 centimeters, a pressure of 75 kPa amounts to applying a mass of around 110 kilograms to this interface.

[0080] If this pressure increases, particularly if it exceeds a threshold, which can be for example of the order of 150 kPa, the grooved patterns can be slightly deformed. This deformation promotes contact and cooperation between the grooved patterns, which improves the transmission of forces between the blades. With a square contact interface of 12 centimeters by 12 centimeters, a pressure of 150 kPa is equivalent to applying a mass of the order of 220 kilograms to this interface.

[0081] THE figures 7 et 8 represent the detail of the arrangement of the members in the case where it is a question of maintaining three superimposed folds together. The three blades considered, are designated by the references 101, 111 and 121, are superimposed two by two, that is to say that the blades 101 and 111 are superimposed at the level of the contact interface I 101-111 and the blades 111 and 121 are superimposed at the level of the contact interface I 111-121. This arrangement can be combined with the previous embodiments. It can in particular be adapted to a greater number of superimposed folds and blades.

[0082] On the figure 7 , the holding system comprises a first set of members - or threaded rods - 30.1 and 30.2 passing through the blades 101 and 111 at the contact interface I 101-111 and a second set of members - or threaded rods - 30.5 and 30.6 passing through the blades 111 and 121 at the contact interface I 111-121. In this way, the intermediate blade 111 is passed through by both sets of members, which ensures continuity in the assembly and holding of the blades together. So that the blade 111 is thus passed through twice, the members 30.1 (respectively 30.2) are offset relative to the members 30.5 (respectively 30.5) in the plane (Oxy) of the two contact interfaces.

[0083] This configuration makes it possible to avoid a single member (for example member 30.1) passing through all of the blades 101, 111 and 121. It is understood that if this remains possible in a three-ply configuration, the use of the same threaded rod to pass through a configuration for example with seven or eight plies would require a longer, thicker rod which would be more expensive and less precise for the assembly of the blades. On the contrary, with members thus offset, these can be short and the multitude of members locally increases the interactions with the grooved patterns, which improves the transmission of forces.

[0084] On the figure 8 , the constructive element 10 comprises a number of folds greater than three. Then additional members 30.9 and 30.10 (as well as two other members not shown in the figures) are added, to hold the blade 121 with the blades of the folds located above it. As can be seen, the members 30.1 (respectively 30.2) are aligned with the members 30.9 (respectively 30.10).

[0085] The organs represented on the figures 7 et 8 are intended to pass through two folds and therefore two blades. In this case, their respective lengths L 30 are substantially equal to the cumulative thickness of the two blades E 101 and E 111 (represented on the figure 12 ) which they pass through and hold together. This has the effect of allowing the members to penetrate the entire thickness of the blades, which increases the proportion of material stressed and, in fact, improves the resistance to tearing of the member in the wood.

[0086] Alternatively, it could be provided that these members pass through a higher number of folds and blades. In this case, it remains preferable, according to the invention, that at least a first member passes through a first part of the folds, that a second member passes through a second part of the folds, the first and second parts of folds having at least one fold in common, the first and second members being at least slightly offset.

[0087] There figure 9 represents an example of the distribution of the different organs of the holding system on the contact interface between several structural blades.

[0088] In this configuration, the constructive element 10 is formed of at least three superimposed folds, of which the blades 101 and 111 are seen (the blade 121 is not shown for reasons of clarity). The holding system 30 is provided with several sets of members, including a first set of four members 30.1, 30.2, 30.3 and 30.4 and a second set of four members 30.5, 30.6, 30.7 and 30.8. The four members 30.1 to 30.4 are provided to hold the blades 101 and 111 against each other at the contact interface I 101-111. The four members 30.5 to 30.8 are provided to hold the blades 111 and 121 (not shown) against each other at the contact interface I 111-121. This configuration therefore uses the principle of holding two blades by four members (as shown in the figure 5 ) and the principle of providing organs to hold together only part of the blades (as illustrated by the figures 7 et 8 ). The organs 30.1 to 30.8 are still in the form of metal threaded rods. As can be seen on the figure 9 , the organs of the first set and those of the second set are slightly offset, to allow these organs to pass through a common blade, in this case blade 111, without obstructing each other.

[0089] In order to achieve optimal support, for each contact interface, the four members of the same set are distributed near the edges of the interface, while ensuring that a gap is maintained with the edge in order to avoid splitting the wood. Thus, it is preferred to arrange the members 30.1 to 30.4 shown on the figure 9 at a distance D 10-30 from the edge of the interface I 101-111 (shown on the figure 12 ) which is between 1.5 and 4 centimeters.

[0090] THE figures 10A et 10B show more precisely the positioning of a holding system at the contact interface. As can be seen, the grooved patterns form a set of pins P. The member 30.1 shown there is positioned in a hollow of the grooved patterns, designated here by the reference C 1234 , at the intersection of the grooves R T12 , R T34 , R L14 and R L23 . In this case, the diameter of the rod 31.1 of the member 30.1 is such that the extent of the member 30.1 on the contact interface I 101-111 is limited to the four patterns P 1 , P 2 , P 3 and P 4 . The organ 30.1 therefore only covers two grooved patterns in each axis, namely the patterns R L23 and R L14 in the axis (Ox) and the pattern R T12 and R T34 in the axis (Oy). It therefore only covers at most four grooved patterns.

[0091] THE figures 11A et 11B represent an example of a metal threaded rod member 30.1 of the holding system 30, which can be applied to all the members 30.1, 30.2 and following which have already been described.

[0092] The member 30.1 of length L 30 comprises a metal threaded rod 31 of generally cylindrical shape. This rod comprises at its opposite ends a head 32 and a point 33. The head 32 is formed of two sub-parts 32' and 32" of different diameters. The upper part 32' is provided with a complementary recess for a screwing tool. The rod 31 is provided with a thread, which can be a single or double thread.

[0093] In the configuration of the figure 11A, the thread of the rod 31 comprises two threads 34' and 34", interlocked and of different diameters. The advantage of this thread lies in the fact that the performance of a thread depends on its pitch and its diameter. The larger the pitch of the thread, the faster the rod penetrates the wood. The larger the diameter of the thread, the more it works the wood locally in shear. The configuration with two interlocking threads of different diameters ensures the local working of the wood in two different shear planes, which makes it possible to reinforce the mechanical resistance of the assembly and to reduce the penetration time of the screw.

[0094] It is important, however, that the thread remains sufficiently narrow, especially for hardwood blades. Also, the ratio between the diameter of the widest thread and the diameter of the shank is preferably between 1.5 and 1.7.

[0095] The invention provides a method for manufacturing a constructive element 10 as described above. This method involves starting with structural blades already provided with grooved patterns on their respective contact interfaces. Alternatively, it may be provided to provide these blades with grooved patterns, for example by machining their faces intended to be superimposed.

[0096] According to the invention, the blades 101 and 111 already provided with the grooved patterns R 101A and R 111B are superimposed in such a way that these grooved patterns come into contact with each other at the contact interface I 101-111. In this respect, advantage can be taken of the complementary shape of the grooved patterns R 101a and R 111B to bring them together until they fit together at least in part, which makes it possible to carry out this superposition step with significant precision.

[0097] Subsequently, the blades 101 and 111 are put under pressure, that is to say pressed against each other, at the contact interface I 101-111. The grooved patterns R 101A and R 111B are thus previously pressed before being actually held together. This pressurizing step can be carried out by various means within the reach of those skilled in the art, for example by applying a weight to the upper blade.

[0098] The pressure used is equal to or greater than 75 kPa, as already indicated above. Depending on the pressure level, the grooved patterns will be nested (which is not possible most of the time with simple superposition) or even crushed and thus slightly deformed, which improves the transmission of forces between the blades thus superimposed and the mechanical resistance of the assembly.

[0099] Finally, the blades 101 and 111 thus superimposed and put under pressure are held against each other by means of a holding system 30, in particular one or more threaded metal rods arranged at the contact interface I 101-111 and passing through the thickness of the blades. The blades are then held against each other, not only with significant positioning precision but also with a better transition of forces between them.

[0100] This process can be repeated in order to assemble all the blades and all the plies of the same constructive element 10, thus allowing complete manufacturing.

[0101] Of course, the present invention is not limited to the examples and embodiments described and shown, but it is susceptible to numerous variations accessible to those skilled in the art as long as these fall within the scope of the invention as defined by the claims.

[0102] In particular, the different forms of connectors which have been described above - as well as other forms within the reach of those skilled in the art upon reading the present description - can be combined within the same construction system, depending on the advantages of each and the specific needs of the construction system.

Claims

1. Method for manufacturing a constructive element (10), comprising the following steps: - at least partially providing the upper face (101A) of a first structural plate (101) with a set of grooved patterns (R101A); - at least partially providing the lower face (111B) of a second structural plate (111) with a set of grooved patterns (R111B) with shapes at least substantially complementary to those of the grooved patterns of the upper face of the first plate (R101A); - superimposing the first plate (101) and the second plate (111) so that the grooved patterns of the upper face of the first plate (R101A) and the grooved patterns of the lower face of the second plate (R111B) are in contact with each other at a contact interface (I101-111), so as to hinder the sliding of the first plate (101) and of the second plate (111) relative to each other along at least one axis (B1); - retaining the first plate (101) and the second plate (111) against each other by a retaining system (30) comprising at least one metal threaded rod member (30.1) at least partially passing through the first plate (101) and the second plate (111) at the contact interface (I101-111); and - characterized in that it comprises a step consisting in, before retaining together the first plate (101) and the second plate (111) by the retaining system (30), putting under pressure the first plate (101) and the second plate (111) against each other with a pressure of at least 75 kPa so that the grooved patterns (R101A, R111B) are slightly deformed.

2. Manufacturing method according to claim 1, wherein the first plate (101) and the second plate (111) are put under pressure against each other with a pressure of the order of 150 kPa.

3. Manufacturing method according to claim 1 or 2, wherein the grooved patterns (R101A, R111B) are arranged so as to hinder the sliding of the first plate (101) and of the second plate (111) relative to each other along at least two non-parallel axes (B1, B2).

4. Manufacturing method according to claim 3, wherein the grooved patterns comprise a first series of grooves parallel to each other (R101A', R111B'), and a second series of grooves parallel to each other (R101A", R111B") but not parallel to the grooves of the first series.

5. Manufacturing method according to claim 4, wherein at least one part of the grooved patterns (R101A', R101A", R111B", R111B") have the shape of a matrix of pins (P), the shapes of which are substantially those of a pyramid with a quadrilateral base.

6. Manufacturing method according to one of the preceding claims, wherein the metal threaded rod member (30.1) comprises a threaded rod (31) provided with a head (32) and a tip (33) arranged at opposite ends of the rod.

7. Manufacturing method according to one of the preceding claims, wherein the metal threaded rod member (30.1) has a generally cylindrical shape.

8. Manufacturing method according to one of the preceding claims, wherein the metal threaded rod member (30.1) comprises at least two interlocking threads (34', 34") of different diameters.

9. Manufacturing method according to one of the preceding claims, wherein the retaining system (30) comprises four metal threaded rod members (30.1, 30.2, 30.3, 30.4) distributed over the entire contact interface (I101-111) and at least partially passing through the first plate (101) and the second plate (111) at the contact interface (I101-111).

10. Manufacturing method according to claim 9, wherein the distance (D10-30) that separates at least one of the members (30.1) from the edge of the contact interface is 30 comprised between 1.5 and 4 centimetres.

11. Manufacturing method according to one of the preceding claims, comprising at least three wooden structural plates (101, 111, 121) of which at least some of the faces (101A, 111B, 111A, 121B) are in pairs superimposed at respective contact interfaces (I101-111, I111-121), wherein the retaining system (30) comprises a first set of metal threaded rod members (30.1, 30.2, 30.3, 30.4) at least partially passing through a first part of the plates (101, 111) and a second set of metal threaded rod members (30.5, 30.6, 30.7, 30.8) at least partially passing through a second part of the plates (101, 111), the first and second parts of plates having at least one plate in common (111), the members (30.1, ... , 30.8) being offset from each other in the planes of the contact interfaces of the plates (I101-111, I111-121).

12. Manufacturing method according to claim 11, wherein the length of the at least one of the members (L30) is substantially equal to the cumulative thickness of the part of plates that it is intended to retain together (E101 + E111).

13. Manufacturing method according to one of the preceding claims, wherein at least one of the members (30.1) is positioned in a recess of the grooved patterns (C1234).

14. Manufacturing method according to claim 11 or 12, wherein the diameter of the at least one of the members (D30) is configured to cover at most four grooved patterns (RL14, RL23, RT12, RT34).