Fastening method using densified wood elements or pieces

Abstract

Disclosed is a fastening method using densified wood elements or pieces, which uses the swelling or set recovery of densified wood, commonly seen as a problem or disadvantage, as a solution for fitting pieces, for example, in assembled products or mechanical assemblies, which allows pieces to be securely fitted and joined without using additional fastening elements such as bolts, screws, nails, adhesives or other metal or plastic fastening means, etc., thus also dispensing with the use of tools to fasten assemblies or joints. The fastening method enables a fit that joins parts or components securely, maintaining the mechanical strength obtained by the densification of the densified wood elements or pieces used for fastening. The proposed fastening method uses sustainable materials, such as radiata pine, which is widely available in Chile and has high densification potential.

Description

[0001] METHOD OF FIXING USING PIECES OR ELEMENTS OF DENSIFIED WOOD DESCRIPTIVE MEMORY

[0002] TECHNICAL FIELD OF THE INVENTION

[0003] The present invention is developed in the field of fastening elements for the construction of wooden furniture and assemblies in general, specifically, it refers to a method of fixing pieces or components of wood densified by swelling.

[0004] BACKGROUND OF THE INVENTION

[0005] The manufacturing industry, particularly the furniture sector, requires a sustainable production strategy to maintain a reliable supply of raw materials over time. More specifically, it is necessary to use materials with a sustainable profile without sacrificing performance. Furthermore, it is often necessary to import wood from abroad to supply furniture manufacturing in Chile.

[0006] Radiata pine is a widely available and affordable tree species in Chile, and extending its uses through densification presents a significant opportunity. However, there is currently no competition in Chile producing and marketing densified wood. Given that this wood is naturally renewable, densification appears as a promising alternative to extend its performance and range of applications. Through a thermo-hydro-mechanical densification (THM) process, softwood, often considered waste, can be transformed into a material with high mechanical performance. THM densification comprises the following stages:

[0007] • To condition and / or plasticize a piece of wood, in order to soften it to prevent fractures under compression;

[0008] • Compress the piece of wood in a specific direction using a press;

[0009] • Simultaneously with compression, the press clamps heat the piece of wood by heat conduction;

[0010] • Leave the fixed part to cool in the press for a period of time until it is mechanically released.

[0011] The stages of this process have been disclosed in several state-of-the-art documents for different wood species.

[0012] For example, document CA2204271 C describes a method for producing wood panels from wood chips and binder by steam-injection pressing of the preformed material to obtain molded material with a predetermined water content. This document describes the stages of conditioning and plasticizing, compression using a press, heating, cooling, and swelling of a wood panel by injecting water into its interior. In this method, the water injection and subsequent swelling are performed solely to improve its mechanical stability by increasing its dimensions and preventing potential failure due to buckling. Document CN114633331 discloses a method for preparing compressed rubberwood with stable dimensions and mold resistance. This method also includes stages of conditioning and plasticizing, mechanical compression using a press with guides, heating the surface of the piece, and allowing it to cool for a period of time.Document CN112157763A also discloses a similar method of densifying natural wood, but does not teach a conditioning and plasticizing of the wood before densification.

[0013] In the article “Wood densification and thermal modification: hardness, set recovery and micromorphology” written by Kristii na Laine and collaborators in 2016, stages of conditioning and plasticizing the piece of wood, compression, heating through electrical resistances and cooling over a period of time are disclosed.

[0014] In the wood densification process, the drawbacks due to dimensional changes caused by swelling are well known. These include immediate natural swelling or elastic recovery (also known as springback) and prolonged swelling or set recovery (also known as set recovery). Springback refers to the recovery of the densified wood's thickness immediately after the compressive load is released, resulting in a relative difference between the thickness obtained after densification and the target thickness. This difference is due to the thermoplastic nature of lignin. Set recovery refers to the recovery of thickness due to exposure to changes in environmental conditions, particularly fluctuations in humidity or high relative humidity, where the densified wood tends to return to its original dimensions.Swelling phenomena are seen as disadvantages, since, in the long term, the piece of wood would lose the mechanical resistance obtained by densification, so chemical products are used to impregnate the wood and / or the application of complementary treatments to the densification in order to reduce the recovery of thickness and favor the dimensional stability of the densified wood.

[0015] In this respect, none of the prior art documents seek to exploit the effects of these swelling phenomena in densified wood as an alternative for joining pieces together. The present invention provides a method for fastening densified wood pieces or elements that takes advantage of swelling or thickness recovery as a solution for adjusting pieces or components, for example, in assembled products or mechanical assemblies, without using additional fasteners such as bolts, screws, nails, adhesives, or other metal, plastic, etc., fastening means, and without tools.

[0016] DESCRIPTION OF THE INVENTION

[0017] The present invention relates to a method of fastening using pieces or elements of densified wood that takes advantage of the swelling or thickness recovery of the densified wood, commonly seen as a drawback or disadvantage, as a solution for adjusting pieces, for example, in assembled products or mechanical assemblies. This method ensures the fit and joining of pieces, assembled products, or mechanical assemblies without using additional fasteners such as bolts, screws, nails, adhesives, or other metal, plastic, etc., fasteners, thus also avoiding the use of tools required for such additional fasteners. By utilizing the swelling or thickness recovery of the densified wood, the strength of the fit and joining of pieces is ensured.

[0018] The fastening method according to the present invention constitutes a sustainable process since it allows for a reduction in the amount of materials required to join parts or components in assembled products or mechanical assemblies. Furthermore, it allows for tool-free joining or assembly, which facilitates the assembly process for individuals who do not possess or lack experience using the tools required for fastening bolts, screws, nails, adhesives, or other fasteners, and / or who suffer from an illness or condition that may hinder the use of such tools or who are unable to exert significant physical effort.

[0019] The proposed fixing method uses sustainable materials, such as radiata pine, which is widely available in Chile and has a high densification potential.

[0020] The fixing method uses pieces or elements of wood previously subjected to a densification process to increase their mechanical resistance and the stress required for their fracture.

[0021] The densified wood pieces or elements obtained are used for fixing parts or components of assembled products / sets or mechanical assemblies, where water is added inside the densified wood pieces or elements to accelerate swelling or thickness recovery in order to obtain a desired or predetermined thickness to generate an interference fit that ensures the union between said parts or components, maintaining the mechanical resistance obtained by the densification of the densified wood pieces or elements used in the fixing.

[0022] The use of multiple pieces or elements of densified wood for the fixing of parts or components can be applied for the manufacture of various products / assemblies or mechanical assemblies, such as wooden furniture formed by the union or assembly of multiple pieces or parts of wood that are fixed or joined together, in a tight manner, using said pieces or elements of densified wood.

[0023] BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings are included to provide a further understanding of the invention and form part of this description and further illustrate a preferred embodiment of the invention, where it can be seen that:

[0025] Figure 1 schematically shows the stages of a densification process to obtain densified wood pieces or elements used in the fixing method, according to an embodiment of the invention.

[0026] Figure 2 schematically shows the dimensional changes of densified wood due to spring-back and set-recovery.

[0027] Figure 3 schematically shows the fitting of a piece or element of densified wood into a part or component, according to one embodiment of the invention. Figure 4A shows a perspective view of possible methods for adding water to pieces of wood to cause them to swell.

[0028] Figure 4B shows an elevation view and a cross-section of possible ways to add water to pieces of wood to make them swell.

[0029] Figure 5A shows a perspective view of possible forms of enveloping body fixing.

[0030] Figure 5B shows an elevation view and a cross-section of possible attachment forms with a wrap-around body.

[0031] Figure 6A shows a perspective view of an assembled chair, according to a particular embodiment of the invention.

[0032] Figure 6B shows an exploded view of the assembled chair, according to a particular embodiment of the invention.

[0033] Figure 6C shows an exploded view of a joining area and a plurality of densified wood pieces, according to a particular embodiment of the invention.

[0034] Figure 6D shows a perspective view of the joining area and the plurality of densified wood pieces joined by the fixing method, according to a particular embodiment of the invention.

[0035] Figure 6E shows a cross-sectional view of a temporal evolution of the joining zone and the plurality of densified wood pieces joined by the fixing method, according to a particular embodiment of the invention.

[0036] Figure 7A shows a graph of the thickness of a piece of wood, to which water has initially been added, as a function of real time. Figure 7B shows a graph of the thickness of a piece of wood, to which water has initially been added, as a function of time, where time is on a base-10 logarithmic scale.

[0037] DETAILED DESCRIPTION OF THE INVENTION

[0038] The invention relates to a method of fastening using densified wood pieces or elements (1) that takes advantage of the swelling or thickness recovery of the densified wood through the addition of water, as a fitting solution for parts, for example, in assembled products or mechanical assemblies. This method ensures the fit and joining of parts without the use of additional fasteners such as bolts, screws, nails, adhesives, or other metal, plastic, etc., fasteners, thus also eliminating the need for tools to create the assemblies or joints. The fastening method creates a fit that ensures the connection between parts or components, maintaining the mechanical strength achieved through the densification of the densified wood pieces or elements (1) used in the fastening.

[0039] The fastening method uses pieces or elements of wood that have been previously subjected to a densification process to increase their mechanical strength and the stress required for fracture. In one modality, the densification process corresponds to a thermo-hydro-mechanical densification process (or THM densification), as shown schematically in Figure 1, which comprises the following stages:

[0040] • plasticize (2) the wooden piece;

[0041] • simultaneously heat (3) and compress (4) the piece of wood; cool (5) the piece of wood for a period of time; and

[0042] • release (6) the piece of wood, obtaining a piece or element of densified wood (1).

[0043] In one modality, the pieces or elements of wood that are subjected to a densification process are wood with a classification of "dry", which corresponds to an internal moisture level not exceeding 18%.

[0044] In one specific method, during the plasticizing stage (2), the wooden piece undergoes a high-temperature humidification treatment to soften it before compression, thus preventing fractures. This humidification can be achieved by subjecting the wooden piece to steam or immersing it in boiling water.

[0045] In one specific embodiment, the wooden piece is placed in a press (7) with two plates (8), such that the wooden piece is positioned between and in contact with said plates (8), and may be in a vertical, horizontal, or any other orientation. The press (7) further comprises heating means, such as an electric resistance element, which allows the wooden piece (3) to be heated. In one embodiment, the heating means allows the temperature of the plates (8) of the press (7) to be raised to 200°C.

[0046] In the compression stage (4), the wood piece is compressed to a predetermined deformation value. In one specific method, a press (7) is used to compress the wood piece, which can be supplemented by using guides parallel to the plates (8), covering the faces of the wood piece to prevent its expansion in the transverse directions. In one method, the deformation of the wood piece in the compression stage (4) is up to a 50% reduction in its height. It has been verified that exceeding a 50% reduction in height results in the development of internal fractures that compromise the structural quality of the wood.

[0047] In one specific modality, in the cooling stage (5), the piece of wood is left at room temperature.

[0048] In one method, the plates (8) are preheated to 200°C. The piece of wood is then placed between the plates (8) of the press (7), and compression begins. The compression process should start as soon as possible to prevent the wood from losing moisture in its original dimensions. Once the required deformation or reduction in height of the wood piece is achieved, the temperature of the plates (8) of the press (7) is reduced in 50°C increments every 60 minutes until the heating element is turned off. The wood piece is then compressed until the plates (8) reach ambient temperature. This takes approximately 20 minutes.Finally, the piece of wood is removed, obtaining a densified piece of wood (1).

[0049] As previously described, and as shown schematically in Figure 2, the densified wood piece (1), once released (6), undergoes dimensional changes due to swelling, where an immediate swelling or spring-back (9) occurs immediately after releasing the densified wood piece (1), generating a relative difference between the thickness obtained after densification and the target thickness. Normally, the relative difference between the thicknesses due to spring-back (9) can be controlled so that it is zero or negligible.

[0050] In addition, the densified wood piece (1) may undergo prolonged swelling or set-recovery (10) due to exposure to changes in environmental conditions, where the densified wood piece (1) tends to recover its original dimensions, which can extend to days, months or years, depending on the environment in which the wood is exposed and mainly due to changes in humidity or conditions of high relative humidity.

[0051] The present invention takes advantage of the swelling phenomenon of densified wood as a solution for adjusting parts or components of assembled products / assemblies or mechanical assemblies, generating an artificial or induced set-recovery (10) by adding water, in a controlled and localized manner, on and / or inside at least a portion of densified wood pieces (1) to accelerate or force the swelling or thickness recovery to obtain a desired or predetermined thickness that allows generating an interference fit that produces a tight joint between said parts or components, maintaining the mechanical strength obtained by the densification of the densified wood pieces or elements (1) used in the fixing.The desired or predetermined thickness obtained due to artificial swelling or swelling induced by the addition of water should not exceed the original dimension of the wood so that the overall mechanical performance of the product or assembled unit to which the attached parts or components belong is not affected.

[0052] In one embodiment, as shown in Figure 3, the fastening method consists of providing at least one piece or element of densified wood (1); providing a piece (11) to be assembled comprising at least one joining area (12) configured to receive at least one portion of the piece or element of densified wood, wherein said joining area (12) is slightly larger than the at least one portion of the piece or element of densified wood (1); placing (13) the at least one portion of the piece or element of densified wood (1) in the joining area (12) of the piece (11) to be assembled; Add (14) water to at least a portion of the densified wood piece or element (1) to generate swelling so that said at least a portion of the densified wood piece or element (1) is in contact with the joining area (12) generating an interference fit (15) with the piece (11) to be assembled.The piece (11) to be assembled can be made of densified wood, non-densified wood, or other material as required.

[0053] The joining area (12) may be configured to partially or completely receive the densified wood piece or element (1). In one embodiment, the joining area (12) is sized, relative to the at least a portion of the densified wood piece or element (1) that it receives, such that it allows for a self-supporting assembly. This enables the at least a portion of the densified wood piece or element (1) received in the joining area (12) to be placed by hand without significant effort, and the piece (11) to be assembled and the at least a portion of the densified wood piece or element (1) are held in place by friction. In a specific embodiment, the size difference between the joining area (12) and the at least a portion of the densified wood piece or element (1) must be between 0.1 and 0.4 mm.

[0054] The joining area (12) can be a through or non-through hole into which the densified wood piece or element (1) is inserted. The densified wood piece or element (1) can be completely inside the hole or partially inside the hole, with a portion outside the joining area (12).

[0055] The portion of the densified wood element (1) that is inserted into the joint zone (12) has a shape corresponding to that joint zone to ensure an interference fit when the densified wood element (1) swells due to the addition of water. The interference fit is achieved through contact between at least two faces of the densified wood element (1) and the joint zone (12). This requirement is necessary because, upon swelling, the densified wood element (1) does not expand uniformly in all directions, but rather almost exclusively in the direction in which it was compressed.

[0056] In one embodiment, adding water to the densified wood element (1) can be done, for example, by using a syringe, by pouring water, or by immersing the portion of the densified wood element (1) where swelling is required. In one embodiment, the water can be added after the densified wood element (1) and the piece (11) to be joined are positioned for joining; or the water can be added to at least a portion of the wood element (1) before it is placed in the joining area (12) of the piece (11) to be joined. It has been empirically identified that, preferably, the amount of water, in mL, required to produce wood swelling sufficient to create an interference fit resulting in a tight joint corresponds to:

[0057] water volume [mL] = (intersection volume of the pieces to be assembled) x 2 The fixing method according to the present invention allows the joining of the densified wood piece or element (1 ) and the piece (11 ) to be assembled without using additional elements such as bolts, screws, nails, adhesives or other means of metal, plastic, etc. fixing, also avoiding the use of tools to obtain the assemblies or joints.

[0058] In a specific modality, as shown in Figures 4A and 4B, to ensure uniform swelling in the original compression direction, water can be added to the densified wood element (1) using a plate-type addition (16), a perforation addition (17), or an external funnel addition (18). In the plate-type addition (16), a hemispherical hole is drilled in the densified wood element (1), transverse to the compression direction, and water is then added to this hole. The perforation addition (17) also involves drilling a hole in the densified wood element (1), but to a greater depth, and no specific shape is required. In the external funnel addition (18), water is added to a funnel in contact with the densified wood element (1) on a face transverse to the compression direction.Whichever method is used to add water, it must allow the water to access the cross-section of the wood fibers in the densified wood element (1), that is, perpendicular to the grain direction, as this allows for better water absorption. Therefore, regardless of the method used to add water, to ensure sufficient water absorption within the first 60 minutes to set the assembly, at least 20% of the total cross-sectional area of ​​the wood fibers must be in direct contact with the water. This requirement is based on the fact that water is absorbed more quickly parallel to the wood fibers.

[0059] In one specific embodiment, as shown in Figures 5A and 5B, the densified wood element (1) can be attached to the joining area (12) in three different ways, depending on the type of piece or element into which it is inserted. These can define an enveloping body corresponding to a chamfered enveloping body (19), a toothed enveloping body (20), and a clean enveloping body (21). The joining area (12) with a chamfered enveloping body (19) has a zigzag shape. The joining area (12) with a toothed enveloping body (20) comprises regularly spaced teeth. The joining area (12) with a clean enveloping body (21) consists of a smooth, uniform surface without gaps.

[0060] In one particular embodiment, the densified wood element (1) corresponds to a first piece or component that must be connected to a second piece or component, wherein the densified wood element (1) comprises a connecting portion that is inserted or fitted into a joining area of ​​the second piece or component. The connecting portion has a shape corresponding to the joining area, but smaller in size, such that when swelling occurs after the addition of water, an interference fit is created connecting the first piece or component and the second piece or component.In this embodiment, the fixing method comprises the steps of: providing a densified wood element (1), which constitutes a first piece or component, comprising a connecting portion; providing a second piece or component comprising at least one joining zone configured to receive the connecting portion of the densified wood element (1); placing the connecting portion of the densified wood element (1) in the joining zone of the second piece or component; adding water to the connecting portion of the densified wood element (1) to generate swelling so that the connecting portion is in contact with the joining zone generating an interference fit that connects the densified wood element (1) and the second piece or component.The second piece or component may be made of densified wood, non-densified wood, or other suitable material required for the manufacture of assembled products / assemblies or mechanical assemblies.

[0061] A possible example of an assembled product, according to the particular modality shown in Figure 6A, is an assembled chair formed by a plurality of wooden pieces and aluminum supports, where the chair components can form assembly pairs defined by a densified wood element (1) and a piece (11) to be assembled comprising at least one joining area (12). As shown in the exploded view of Figures 6B to 6E, a wooden piece corresponding to one of the chair legs acts as a piece (11) to be assembled with a joining area (12), and a wooden piece corresponding to a chair back element acts as a densified wood element (1) that is inserted into the joining area (12) of said piece (11).In turn, the chair part (11) may correspond to the densified wood element (1) of another assembly pair, as shown in Figures 6C to 6E, where said part (11) is inserted into a hole (22) in the chair seat (23), and said hole (22) defines a respective joining zone (12). The hole (22) may be funnel-shaped to facilitate the addition of water. In Figure 6D, the densified wood pieces are illustrated at the initial moment. After the addition of water, the densified wood pieces swell and create an interference fit between the chair leg and the backrest element, and between the chair leg and the hole (22) in the seat (23), until they are completely fixed, as shown in Figure 6E.

[0062] In one particular embodiment, the densified wood element (1) corresponds to a cylindrical element or dowel for connecting two pieces or components, preferably made of wood. In this embodiment, the fastening method comprises the steps of: providing a first and second piece or component to be connected, comprising one or more corresponding connection holes between the pieces or components; inserting a densified wood element (1) into each connection hole of the first piece or component; inserting each densified wood element (1) into each corresponding connection hole of the second piece or component; adding water to each inserted densified wood element (1) to produce swelling so that each densified wood element (1) comes into contact with the connection holes of the first and second pieces or components, creating an interference fit and connecting said first and second pieces or components.The first and second pieces or components may be made of engineered wood, non-engineered wood, or other suitable material required for the manufacture of assembled products / assemblies or mechanical assemblies. The engineered wood elements (1) have a smaller initial diameter than the connection holes of the first and second pieces or components, whereas the connection holes of the first and second pieces or components have the same diameter.

[0063] By using the densified wood element (1) as a dowel to connect two pieces or components, a tight joint between the connection holes of each piece or component is ensured after the addition of water.

[0064] An example of an assembly that can be obtained with this particular method is a set of laminated timber beams comprising a plurality of transverse through-holes, into which a respective cylindrical densified timber element (1) is inserted to connect the timber beams transversely. This type of assembly follows a principle similar to the system known as DLT (“dowel laminated timber”), which traditionally uses only solid timber. However, the novelty of the present proposal lies in the use of cylindrical densified timber elements (1) instead of solid timber, which connect the timber beams transversely, taking advantage of the swelling method of the densified timber. As a result, an interference fit is generated between the cylindrical densified timber elements (1) and the timber beams, forming a structural assembly.

[0065] The features and advantages of the present invention will become apparent from the following description. The description presented represents a broad definition of the invention, such that changes and modifications within the spirit and scope of the invention will be evident to a person skilled in the relevant technical field. The scope of the invention is not intended to be limited to the particular forms disclosed, and the invention covers all modifications, equivalents, and alternatives that fall within the spirit and scope of the invention as defined in the claims.

[0066] EXPERIMENTAL DEVELOPMENT:

[0067] In order to demonstrate the fastening potential of the densified wood assembly method, a densified wood element (1) with an original square cross-section of 15.9 x 15.9 mm is tested. Water is initially added to the element, and once released at time 0, it begins to expand. The increase in thickness over time can be measured using a swelling rate, which is defined as:

[0068] rmm-i Final thickness — Initial thickness

[0069] Swelling rate - — = - : — : - L hr J Time interval

[0070] Figure 6A shows that the swelling rate within the first hour is 0.8 mm / hr. Within the first 4 hours, this rate is 0.325 mm / hr. Finally, in the first 12 hours, the swelling rate is 0.175 mm / hr. Therefore, the greatest growth potential through swelling is achieved in the first hour.

[0071] Figure 6B shows the thickness values ​​of the densified wood element (1) as a function of time, but on a logarithmic scale and recording the swelling ratio between different times, which is defined as:

[0072] Final thickness — Initial thickness

[0073] Swelling ratio (%) = - - - x 100

[0074] Initial thickness

[0075] In Figure 6B, the thickness exhibits a profile similar to a straight line with respect to time on a logarithmic scale. It is important to note that, during the first hour, the swelling ratio is 5.03, which is similar to the value obtained between times "120m" and "12h". That is, during the first hour, a swelling ratio similar to that obtained over an 11-hour interval is observed at later times. This again highlights the importance of using the first hour to secure the densified wood element (1).

Claims

CLAIMS 1. A method of fastening using densified wood elements, which ensures the fit and joining of parts, without using additional fastening elements such as bolts, screws, nails, adhesives or other means of metal, plastic, etc. fastening, also avoiding the use of tools for fixing assemblies or joints, CHARACTERIZED in that it comprises the steps of: • provide at least one element of densified wood (1); • provide a piece (11) to be assembled comprising at least one joining area (12) configured to receive at least a portion of the densified wood element (1), wherein said joining area (12) is larger than the at least one portion of the densified wood element (1); • place (13) at least a portion of the densified wood element (1 ) in the joining area (12) of the piece (11 ) to be assembled; • add (14) water to at least a portion of the densified wood element (1 ) to generate swelling so that said at least a portion of the densified wood element (1 ) is in contact with the joining area (12) generating an interference fit (15) with the piece (11 ) to be assembled.

2. The fixing method according to claim 1, CHARACTERIZED in that the densified wood element (1) is placed (13) completely in the joining area (12) of the piece (11) to be assembled.

3. The fixing method according to claims 1 or 2, CHARACTERIZED in that the addition of water to at least a portion of the densified wood element (1) is carried out by means of a syringe, by pouring water or by immersion.

4. The fastening method according to claims 1 to 3, CHARACTERIZED in that the at least one densified wood element (1) is obtained by subjecting a wood element to a densification process, comprising the steps of: • laminate (2) the wooden element; • heat (3) and compress (4), simultaneously, the wooden element; • cool (5) the wooden element; • release (6) the wood element, obtaining the densified wood element (1).

5. The fastening method according to claims 1 to 3, CHARACTERIZED in that the at least one densified wood element (1) is obtained by subjecting a wood element to a densification process, comprising the steps of: • preheat two plates (8) in a press (7); • place the wooden element in the press (7) with the two plates (8), wherein said wooden element is placed between said plates (8); • compress the wooden element to a predetermined deformation value; cool the wooden element, maintaining compression; • release the wood element, obtaining the densified wood element (1).

6. The fixing method according to claim 5, CHARACTERIZED in that the plates (8) are heated to a temperature of 200°C.

7. The fixing method according to claim 5, CHARACTERIZED in that the plates (8) are allowed to cool until they reach room temperature.

8. The fixing method according to claim 5, CHARACTERIZED in that the wooden element is compressed until the deformation of the wooden element reaches up to a 50% reduction in its height.

9. The fastening method according to claim 5, CHARACTERIZED in that it comprises: placing the wooden element between the plates (7) of the press (8); heating the plates (7) to a temperature of 200°C; compressing the wooden element until a deformation equivalent to a reduction of up to 50% of the height of the wooden element is achieved; reducing the temperature of the plates (8) in 50°C increments every 60 minutes, until no further heat is applied through the plates (8); maintaining the compression until the plates (8) reach ambient temperature; releasing the wooden element, obtaining the densified wooden element (1).

10. A fastening method using densified wooden elements, which ensures the fit and joining of parts, without using additional fastening elements such as bolts, screws, nails, adhesives, or other metallic, plastic, etc., fastening means, also avoiding the use of tools for the fastening of assemblies or joints, CHARACTERIZED in that it comprises the stages of: • provide a densified wood element (1), which constitutes a first piece or component, comprising a connecting portion; • provide a second piece or component comprising at least one joining area configured to receive the connecting portion of the densified wood element (1); • Place the connecting portion of the wooden element (1) in the joining area of ​​the second piece or component; • Add water to the connecting portion of the densified wood element (1) to generate swelling so that the connecting portion is in contact with the joining area, creating an interference fit that connects the densified wood element (1) and the second piece or component.

11. A method of fastening using densified wood elements, which ensures the fit and joining of parts, without using additional fastening elements such as bolts, screws, nails, adhesives or other means of metal, plastic, etc. fastening, also avoiding the use of tools for fixing assemblies or joints, CHARACTERIZED in that it comprises the steps of: providing a first and second piece or component to be connected, comprising one or more corresponding connection holes between the pieces or components; • insert a cylindrical densified wood element (1) inside each connection hole of the first piece or component; • Insert each densified wood element (1) into each corresponding connection hole of the second piece or component; • Add water to each densified wood element (1) inserted to produce swelling so that each densified wood element (1) is in contact with the connection holes of the first and second piece or component, generating an interference fit, connecting said first and second piece or component.

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