WO2010081965A1

WO2010081965A1 - Connecting piece for components made of wood, or derivative, and method of using same

Info

Publication number: WO2010081965A1
Application number: PCT/FR2010/000028
Authority: WO
Inventors: Till Breitfuss
Original assignee: Till Breitfuss
Priority date: 2009-01-15
Filing date: 2010-01-14
Publication date: 2010-07-22
Also published as: FR2941021A1

Abstract

The connecting piece is a piece made of wood (I1) having a cross section that is rectangular in a first plane and a cross section that is at least substantially rectangular in a second plane orthogonal to said first plane, configuration obtained by compressing a piece which, at the outset, has a rectangular cross section in the first plane and, in a second plane orthogonal to the first plane, as a cross section with at least one dovetailed region. It allows components (6,7) to be joined together by frontal insertion into mortises (8a, 9a) (8b, 9b) created, facing one another, in these components, with the piece (I1) returning thereafter to the geometry it had prior to compression.

Description

Joining piece for wooden elements, or derivative, and method of use.

The present invention relates to a new means for assembling wooden elements or derivatives, for example of furniture elements, using the principle of the dovetail.

Conventionally, for a dovetail assembly, an element comprises at least one trapezoidal tenon whose large base constitutes the free end, the other element comprising a mortise of complementary section, the small base and at least one lateral face of said mortise opening on two different faces of the element. Given this geometry, the tenons can be put in place only by introduction into the lateral side opening of the mortise and sliding side. In addition, since a side face of the mortise opens on one side of the element different from that against which comes to apply the assembled element, the assembly remains visible, once done. Glue is generally used to permanently immobilize the assembly and, even if the assembly is glued, it may happen that, under the effect of efforts, the tenon slides in the opposite direction and out more or less of the mortise .

The invention aims to achieve an invisible assembly, requiring no tool for the establishment of the tenon in the mortise, involving no sliding between parts and can be used without glue, while being irreversible .

This object is achieved in that the invention provides a wooden connecting piece which, while it is in the free state and not exposed to a swelling fluid, has a rectangular section in a first plane and a at least substantially rectangular section in a second plane orthogonal to said first plane, said part being obtained by compression of a preform having a rectangular section in said first plane and a section having at least one dovetailed zone in a second orthogonal plane in the foreground, compression which is exerted on the side walls of said preform.

This compression results in giving the same size to the large base and the small base of the dovetail, which obviously increases all the more the density that one is closer to the big base. This is what we will hear, later, by "differential density".

It follows that the connecting piece can be defined from its density: while it is in the free state and not exposed to a swelling fluid, the piece has, in the second plane, a density which from a maximum value at one of its ends to a minimum value, so that, if the density of the part was uniform and close to said minimum density, it would have a rectangular section in said first plane and a section having at least one dovetailed zone in said second plane.

Thus, while it is in the free state and not exposed to a swelling fluid, the assembly part according to the invention has a parallelepipedic configuration.

Such a geometry makes it possible to introduce the piece into a dovetail mortise, not laterally, that is to say by one of the open side faces of the mortise and slide, but frontally, that is, that is to say via its small opening base, the mortise being devoid of side faces s Opening on one side of the element to be assembled, other than that affected by its small base. Under the effect of means that will be described later, the piece then resumes its original configuration, dovetail, while it is already in place in the mortise and it is finally imprisoned.

The document DE 1 939 838 imagines, certainly, the use of a part having, in appearance, a similar geometry, but, on the one hand, the piece is, "preferably in inflatable plastic material", without it give any indication as to the nature of this plastic material and the means used to make it inflate and, on the other hand, the intended application is different: it is the construction of drywall elements where the parts have a sealing function. It seems likely that the mortises created in the elements of dry walls affect the whole length of the elements and that the parts of assembly are profiles. In any case, DE 1 939 838 does not describe or suggest the use of wooden assembly parts whose geometry is modified by compression to allow frontal insertion into a dovetailed mortise and then return to the piece to its original geometry.

On the other hand, there are known assembly methods applicable to elements similar to those of the invention and according to which an assembly part, consisting of a cylindrical pin or a thin and flat tongue, is inserted frontally into, respectively, a pair of cylindrical blind holes or a pair of cylinder-shaped recesses created in the elements to be assembled and arranged facing each other, processes that are not however based on the principle of assembly dovetail.

According to US Pat. No. 3,442,311, an assembly of parts alternately having dovetailed tenons and mortises adapted to interpenetrate frontally is also known. However, the tenons already have a dovetail shape before the interpenetration, which requires a forced penetration into the mortises with temporary mutual deformation of the tenon and the mortise. If one adds that in US 3,442,311, the mortises open not only frontally but also bilaterally, with the result that the assembly is visible, this forced penetration limits the application of the method to unexposed assemblies. visible or low-quality products, in that the penetration force necessarily leads to damage parts, unless they are made of a very elastic. In addition, as indicated above, when the mortises open bilaterally, it can happen that, under the effect of efforts, the tenons slide and spring laterally mortises. On the contrary, the introduction of the assembly part according to the invention exerts no violence on the walls of the mortise, which can be created in a thick and hard element, therefore inelastic, and which opens only frontally , which makes it possible to obtain an invisible and irreversible assembly. In a first embodiment of the invention, the density of the part, in said second plane, ranges from a maximum value at one of its ends to an intermediate minimum value, and then from this minimum value to a maximum value, so that, if the density of the part was uniform and close to said minimum density, it would have a rectangular section in said first plane and a section having, in said second plane, two adjoining dovetailed zones by their small base, the resulting part thus forming an independent assembly stud.

It is understood that the term "docked" used above does not mean that the two dovetailed areas belong to two separate pieces which have been joined together "small base against small base": the two dovetails are d one piece and their small bases merge.

In a second embodiment, the density of the workpiece, in said second plane, ranges from a maximum value at one of its ends to a minimum value so that, if the density of the workpiece was uniform and adjacent to said minimum density, it would have a rectangular section in said first plane and a dovetail section, in said second plane, said piece being in one piece, small side of the dovetail, with a first element to be assembled to a second element, and forming assembly pin.

The piece can be made of different types of wood, but beech is generally preferred in this means that it is easily available, inexpensive and capable of quick and easy compression / expansion.

Under the effect of a fluid swelling, the piece is likely to recover the configuration it had before compression, that is to say a substantially uniform density, close to said minimum density (abstraction, of course, the insignificant change in density due to the presence of swelling fluid).

By swelling fluid is meant water, a dilute solution of adhesive, a liquid or liquefiable adhesive, or any other medium, not necessarily aqueous, capable of reversing the compression of the part. In a preferred embodiment, the moisture is provided by a dilute solution of glue. Another possibility is to pre-glue the lateral faces of the preform before compression, the glue thus deposited and dried being activated, by humidification, at the time of use.

Whether the piece is a dowel or tenon, the wood grain is substantially perpendicular to the bases of the dovetail (s). In addition to the piece has a better tensile strength than if the direction of the wire was any, it accelerates the return of the piece to its original shape by faster penetration of the swelling fluid between the wood fibers. In the case where the connecting piece is an independent stud, the method of assembling two elements to join, wood or derivative, using such a stud, comprises: a. creating, in each of said elements, a dovetail mortise opening on the small base side, on that of the surfaces of the element which is to abut against a surface of the other element; b. deposition of swelling fluid in said mortises; vs. the establishment of one of the zones, differential density, of the stud in the mortise of one of the two elements, by frontal introduction into said mortise; d. placing the mortise of the other element on the other zone, at differential density, of said stud, by frontal insertion of said mortise on said other zone; summer. waiting for said stud to hold a configuration in which it has a substantially uniform density close to said minimum density, that is to say the return of the stud to the configuration it had before compression, it being understood that the step b may be replaced by a deposition of swelling fluid directly on said stud. Step e can be extremely short: for a stud in occupying beech, in the compressed state, a volume of about 2 cm ³ , it is less than 30 seconds if the swelling fluid is water. This duration will be longer as the swelling fluid is more viscous, ideally that the expansion time is minimal while allowing insertion into the two mortises vis-à-vis.

The invention also extends its scope to any wooden element incorporating, as tenon (s) assembly, at least one stud piece according to the invention. In this case, the method of assembling such a wooden element or derivative, said first element, and a second wooden element or derivative to be joined to the first is by: a. creating, in said second element, at least one mortise dovetail emerging, small base side, surface of the element; b. deposition of swelling fluid in said mortise; vs. placing said at least one stud, with a differential density, of said first element in said at least one mortise of the second element, by frontal insertion into said mortise; and F. waiting for said stud to hold a configuration in which it has a density substantially uniform and close to said minimum density, that is to say the return of said at least one stud to the configuration it had before compression, it being understood that step b can be replaced by a deposition of swelling fluid directly on said post,

When it comes to assemble two elements by several pairs of studs (tenon) / mortise, it may be advantageous for one of the pairs of mortises vis-à-vis to be exactly the same length as the stud (tenon). ), the stud group (tenon) / mortises in cause determining the final relative position of the elements to be assembled, and that the other pairs of mortises vis-à-vis are a length slightly greater than that of the stud or tenon, this which allows a slight lateral offset to allow machining tolerances of the mortises in the lateral direction.

The invention extends its scope to the manufacturing process of the assembly part defined above, which method consists of: from a wooden preform having a rectangular section in a first plane, a section having at least one zone at the bottom dovetail in a second plane orthogonal to the first and opposite side faces; exerting pressure on said opposite side faces of the preform so that said dovetail area changes from its initial configuration to a configuration whose section in said second plane is also substantially rectangular, so that after such compression, there is obtained the expected assembly part having a substantially parallelepipedic configuration configuration that it keeps as it is not subjected to a fluid causing swelling.

The invention will be better understood on reading the following description, made with reference to the appended drawings in which: - Figure 1 shows, in perspective, a preform according to the invention, according to a first embodiment;

- Figure 2 is a view similar to Figure 1, but after compression;

- Figure 3 is a perspective view of two elements to be assembled by means of studs according to the invention;

FIGS. 4a-f illustrate the different steps of an assembly applied to elements comprising several pairs of studs / mortises, FIGS. 4a-4c and 4f being full perspective views, FIG. 4e being a sectional view taken in the plane P3 of FIG. 4f and FIG. 4d being a view similar to FIG. 4e but before swelling of the tenon;

FIGS. 5 and 6 are views similar to FIGS. 4d and 4e, respectively, but showing the case where the assembly part according to the invention is not an independent stud but a stud belonging to one of the elements to assemble, and

- Figure 7 shows, in perspective, a preform according to the invention, according to a second embodiment.

Referring to FIG. 1, a stud preform 1 having, in the plane P1, a rectangular section and in the plane P2, orthogonal to P1, a section with a double dovetail 2, 3 is shown. Each dovetail has a large base, respectively, 2G, 3G and a small base, respectively, 2P and 3P which merge. The stud preform thus comprises a front face 4 and a flat rear face, a right side face 5 and a very open V-shaped left side face and a 90 ° layer, and upper and lower faces which correspond to the large 2G bases. 3G. This stud preform is a piece of wood, whose fibers are oriented substantially perpendicular to the large bases 2G, 3G. By exerting pressure on the opposite side faces of the stud preform, the assembly piece having the configuration shown in FIG. 2 is obtained. In this configuration, the large 2G, 3G bases have been narrowed to be the same size as the small 2P, 3P bases. Although, in the representation of Figure 2, we no longer see any trace of the existing slope change, in Figure 1, in the side faces 5 at 2P, 3P, in practice, the faces 5 may not be also perfectly flat and a residue of the change of slope can remain visible. The important thing is that in the configuration of Figure 2, the stud has a substantially rectangular section in the plane P2. In this configuration, the wood fibers are obviously all the more compressed as we move away from the small bases 2P, 3P to approach the large bases 2G, 3G, so that the density of the room passes from a maximum value at the large base 2G to decrease to a minimum value at the small base 2P, 3P from which it grows to a maximum value at the large 3G base. The piece therefore has a differential density.

It should be noted that once compressed to the configuration shown in Figure 2, the stud retains this configuration as it is not subject to a medium causing its swelling, the only ambient air being incapable.

Figure 3 shows two elements 6 and 7 to assemble. These are two elements in wood, solid or not, which can be furniture elements, walls of a box, etc. Each of these elements comprises two mortises, respectively 8a, 8b and 9a, 9b, dovetail. As can be seen, the mortises 8a, 8b only open on the face 6a of the element 6 and the mortises 9a, 9b only open on the surface 7a of the element 7. The objective is to assemble the elements 6 and 7 so that the surface 7a is applied against the surface 6a.

The mortises 8a, 8b and 9a, 9b were machined using a dovetail cutter. It is understood that, as used according to the invention, the cutter attacks the element in 10 by digging a bowl, it is subjected to a translation movement to the right, in the drawing, movement that creates the mortise 8a , after which it is translated to the left, and is removed from the element when it is returned to 10. It may not be subjected to such a return in 10 and extract at the end of its race to the right, but in this case it would be created a second bowl 10. The bowl 10 has no use in the assembly process, except to offer a space likely to receive a possible excess of swelling fluid. The length of the mortises 8a and 9a is equal to the length L of the stud while the length of the mortises 8b and 9b may be slightly greater than the length L so as to provide a small adjustment game.

The assembly method is illustrated in Figures 4a to 4f.

Figure 4a is identical to Figure 3 which has just been described. Figure 4b shows the element 7, in the mortise 9a of which was placed a drop of swelling fluid C, and the element 6 in the mortise 8a of which a drop of swelling fluid C is being deposited.

FIG. 4c shows the element 7, having a drop of inflation fluid in its two mortises 9a, 9b, and the element 6 in the mortises 8a, 8b of which has been inserted frontally, that is to say in the direction F of FIG. 4c, a differential density half, such as 2 'or 3', of two studs 1 ', the other differential density half, such as 3' or 2 ', protruding on the surface of the element 6. The next step is the establishment of the element 7 on the projecting half of the studs by frontal introduction of the mortises 9a, 9b on said halves, according to the arrow F of Figure 4d. Figure 4d is a section along a plane parallel to the plane P2 and passing through one of the studs: we see that the stud still has the configuration and that it does not occupy the entire space of the two mortises in vis-à-vis.

After a few moments, as shown in Figure 4e, the stud has a configuration similar to that of the preform 1, and now comes to rest on the oblique walls of the mortises. It is therefore impossible to separate the elements 6 and 7, the studs having a further self-tightening effect. The result is an invisible assembly, as shown in Figure 4f.

Note that an invisible assembly is also obtained when using the previously known techniques referred to above, namely "cylindrical pin / cylindrical blind hole" couples or "oval tab / mortise portion of cylinder", but the technique employing "cylindrical trunnions / cylindrical blind holes" does not allow for lateral adjustment and, if the technique employing "oval tabs / mortise sections in cylinder sections" allow, it does not lead to an effect of self-tightening. Only the technique according to the invention allows both invisibility, adjustment and self-tightening.

Figures 5 and 6 illustrate another embodiment in which the part according to the invention is not independent, but is an integral part of one of the elements to be assembled and therefore constitutes a tenon. The assembly method is identical to what has just been described with reference to FIGS. 4a-4f, except that the tenon already being integral with one of the elements, it is only necessary to introduce a drop of fluid swelling C in the mortise 8b ', to put on the front differential density tenon in this mortise and to let it inflate.

Thus, the element 7 'shown in Figure 5 comprises a tenon differential density 10' which corresponds to half of the pin 1 'of Figure 2 and is introduced into a mortise 8b' mortise 8b of the figure

4d.

FIG. 6 shows the completed assembly, the tenon having inflated to the point of having the same configuration as the dovetail 3 of the preform of FIG.

This embodiment is particularly interesting for the construction of chairs to the extent that each assembly is almost instantaneous, thus requiring no belting of the chair time takes the glue, as is the case in the technique currently used.

Figure 7 shows a second embodiment of the preform according to the invention. This second embodiment IA has, in the plane P1, a rectangular section and, in the plane P2 orthogonal to P1, a section comprising two dovetail zones 20 and 30 having, respectively, a small base 20P, 30P and a large 2OG, 3OG base. The small bases 2OP, 3OP are not directly contiguous, as is the case in the preform 1 of FIG. 1, but joined by a bridge of material 50.

Subject to compression exerted on its side faces, the preform IA takes the same configuration as the preform 1, that is to say, a substantially parallelepipedic configuration. It is understood that, when using an assembly part obtained from a preform type IA, it adapts, accordingly, the shape of the receiving mortise.

It is also understood that the piece 7 ', 10' of FIG. 5 could be modified to incorporate an assembly piece designed according to the same principle, that is to say that the small base of the dovetail 10 'would not not directly contiguous to the element 7 ', but joined to it by a bridge of material.

It is understood from the foregoing that the invention allows an invisible assembly, self-tightening, very fast, not requiring, for the meeting, neither tool nor necessarily glue, and operating by direct presentation of both elements in their final position, while allowing machining tolerances. The assembly is all wood, resulting, consequently, on buildings recyclable and respecting the environment.

Claims

1. Connecting piece for wooden or derived elements, consisting of a piece of wood (I ¹ ; 10 ') having a rectangular section in a first plane (Pl) and a section at least substantially rectangular in a second plane ( P2) orthogonal to said first plane, characterized in that, while it is in the free state and unexposed to a swelling fluid, the piece has, in said second plane (P2), a density that ranges from maximum value at one of its ends (2G and / or 3G) to a minimum value, so that, if the density of the part was uniform and close to said minimum density, it would have a rectangular section in said first plane (Pl) and a section having at least one dovetail area (2 and / or 3) in said second plane (P2).

2. Part according to claim 1, characterized in that, in said second plane (P2), the density of the workpiece (I ¹ ) ranges from a maximum value at one of its ends (2G) to a minimum value at an intermediate position, then from this minimum value to a maximum value (3G), so that, if the density of the part was uniform and close to said minimum density, it would have a rectangular section in said first plane

(Pl) and a section having, in said second plane (P2), two dovetail zones (2,3; 20,30) contiguous to their small base (2P, 3P) or whose small bases

(20P, 30P) are joined via a material bridge (50), the workpiece thus forming an independent assembly bolt.

3. Part according to claim 1, characterized in that, in said second plane (P2), the density of the piece

(10 ') goes from a maximum value at one of its ends to a minimum value so that, if the density of the part was uniform and close to said minimum density, it would have a rectangular section in said first plane (P1) and a dovetail section in said second plane (P2), said part being in one piece, small side of the dovetail, with a first element (7 ¹ ) to be assembled to a second element (6 '), and forming an assembly pin.

4. Part according to any one of claims 1 to 3, characterized in that the wood grain is substantially perpendicular to the bases (2G and / or 3G) of said at least one dovetail area.

5. Part according to any one of the preceding claims, characterized in that it is beech.

6. Part according to any one of the preceding claims, characterized in that, under the effect of a swelling fluid, it is capable of adopting a configuration (l; 10) in which it has a substantially uniform density, close to said minimum density.

7. A method of assembling two wooden elements, or derived, to be joined by: a. creating, in each of said elements (6, 7), a dovetail mortise (8a, 9a) opening, on the small base side, on that of the surfaces of the element which is to be placed against a surface of the other element; b. deposition of swelling fluid (C) in said mortises; vs. placing one of the dovetail zones (2 or 3) of the stud (I ¹ ) according to any one of claims 2 or 4 to 6, when dependent on claim 2, in the mortise (8a) of one (6) of the two elements, by frontal introduction into said mortise; d. placing the mortise (9a) of the other element (7) on the other dovetailed zone (3 or 2) of said stud, by frontal introduction of said mortise on said other zone; summer. waiting for said stud to take a configuration (1) in which it has a substantially uniform density and close to said minimum density, it being understood that step b may be replaced by a deposition of swelling fluid directly on said stud (I ¹ ).

8. Wooden element or derivative (7 ') incorporating, as studs (s), at least one piece (10') forming a pin according to claim 3 or according to any one of claims 4 to 6 when they depend on claim 3.

9. A method of assembling a first element (7 ') of wood or derivative according to claim 8 and a second wooden element, or derivative, to be joined to the first by: a. creating, in said second element (6 ¹ ), at least one dovetail mortise (8b ¹ ) opening, small base side, surface of the element; b. deposition of swelling fluid (C) in said mortise; vs. placing said at least one tenon (10 ') of said first element, respectively in said at least one mortise (8b ¹ ) of the second element, by frontal insertion into said mortise, and f. waiting for said stud to grip a configuration (10) in which it has a substantially uniform density and close to said minimum density, it being understood that step b can be replaced by a deposition of swelling fluid directly on said tenon (10 ').

10. The method of claim 7, applied to the case of the assembly of two elements by several couples of assembly part / mortise, characterized in that it consists in giving one of the couples of mortises vis-à-vis - screw (8a, 9a) the same length as that of the connecting piece and the other or the other couples of mortises (8b, 9b) a length slightly greater than that (L) of the corresponding connecting piece .

11. Method according to any one of claims 7, 9 or 10, characterized in that the fluid swelling is water, a dilute solution of adhesive or a liquid or liquefiable adhesive.

12. A method of manufacturing the part according to any one of claims 1 to 6, characterized in that it consists of a wooden preform (1; 1A) having a rectangular section in a first plane (Pl) a section having at least one dovetail area (2 and / or 3; and / or 30) in a second plane (P2) orthogonal to the first and opposite side faces (5); pressurizing said opposite side faces (5) of the preform (1; 1A) so that said dovetail area (2 and / or 3; 20 and / or 30) is moved from its initial configuration to a configuration whose section, in said second plane (P2), is also substantially rectangular, so that after such compression, the expected assembly piece (1 ') having a substantially parallelepipedic configuration is obtained, the configuration being it keeps as long as it is not subjected to a fluid causing its swelling.