Formwork system and its manufacturing process

Abstract

The invention relates to a formwork device comprising a formwork panel (2) made of a wood-based material and delimited by two main faces (20, 21) and lateral edges (23), characterized in that a removable protective shell (3) made of plastic material is associated with said panel, said shell comprising: - a peripheral edge (30) configured to cover and removably enclose the lateral edges (23) of the panel (2), - a main wall (31) configured to be positioned against a main face (20) of the panel (2), which main wall comprises an external face forming a formwork face, - the main wall (31) and the peripheral edge (30) forming a monobloc structure delimiting a cavity (32) into which the panel (2) is inserted. Figure 1

Description

Title of the invention: Formwork device and its manufacturing process. Technical field

[0001] The invention relates to a formwork device and its manufacturing process.

[0002] The invention relates in particular to the technical field of formwork devices used in the technical sector of construction and / or building and public works (BTP), and more particularly to formwork devices intended for the formation of concrete structures, in particular floors. State of the art

[0003] Traditional formwork panels or modular panels from industrial formwork systems are widely used in the construction sector, particularly in floor construction, to mold and hold fresh concrete in place until it reaches sufficient strength to support the intended loads. These panels have a generally parallelepiped shape defined by two main faces and lateral edges. They are usually made from wood-based materials, such as plywood or particleboard, due to their ease of use, relatively low cost, and ability to provide a smooth formwork surface for the concrete.

[0004] Once the concrete has hardened, the panels are dismantled and reused for other projects. However, during handling, installation, and stripping, traditional panels are subject to wear and tear, which limits their useful life and necessitates frequent repairs or replacements. On average, a traditional formwork panel can be reused 8 to 10 times before being replaced.

[0005] When panels are too damaged to be reused, they can potentially be recycled. The recycling process may include grinding the panels into wood chips for reuse in the manufacture of new panels or for other industrial applications. However, recycling may be limited by the presence of contaminants such as concrete residues or non-stick surface treatments on the panels. In this case, the panels are generally sent to landfill, but at the cost of a significant environmental impact.

[0006] The invention aims to remedy all or some of the aforementioned drawbacks. In particular, the invention aims to achieve all or some of the following objectives: extend the useful life of formwork panels; reduce the replacement and maintenance costs of formwork panels; improve the quality of concrete surfaces obtained after stripping; and provide a solution for recycling the panels. of used prior art contributing to reducing construction waste and environmental impact. Presentation of the invention

[0007] The solution proposed by the invention is a formwork device comprising a formwork panel made of a wood-based material and delimited by two main faces and lateral edges. A removable protective shell made of plastic material is associated with said panel, said shell comprising: - a peripheral edge configured to cover and removably enclose the lateral edges of the panel; a main wall configured to be positioned against a main face of the panel, which main wall includes an external face forming a formwork face. The main wall and the peripheral edge form a single-piece structure delimiting a cavity into which the panel is inserted.

[0008] The protective plastic shell encases the formwork panel, effectively protecting its lateral edges and one of its main faces from wear, impacts, and damage caused by handling, installation, and stripping operations. This protection extends the useful life of the panels, which can be used dozens or even hundreds of times, thus reducing replacement and maintenance costs. Furthermore, the outer face of the shell, designed to act as formwork, provides a continuous and homogeneous surface, which improves the quality of the concrete surfaces obtained after stripping. The removable nature of the shell also allows for easy replacement without damaging the formwork panel itself.

[0009] Finally, the invention offers the possibility of installing the protective shell on prior art formwork panels (traditional or modular panels from industrial formwork systems) that are considered too damaged for conventional reuse. These panels, which in principle would have had to be shredded or sent to landfill due to the deterioration of their wooden formwork surface, can thus be recovered and reconditioned. The plastic shell makes it possible, in particular, to cover the imperfections and / or damage of the used panels, thereby restoring their functionality for formwork operations. The invention thus offers a new solution for recycling damaged panels, contributing to the reduction of construction waste and environmental impact.

[0010] Other advantageous features of the invention are listed below. Each of these features can be considered alone or in combination with the notable features defined above. Each of these features contributes, where appropriate, to solving specific technical problems defined further in the description and in which the others do not necessarily participate. characteristics defined above. The following characteristics may therefore be the subject, where appropriate, of one or more divisional patent applications:

[0011] According to one embodiment, the peripheral edge of the shell includes at least one internal rib projecting into the housing, which rib is configured to engage in a complementary groove provided on at least one lateral edge of the panel.

[0012] D According to one embodiment, the peripheral edge of the shell is stapled to the lateral edges of the panel.

[0013] According to one embodiment, the shell is made of a plastic material having a Shore A hardness between 45 and 70, advantageously between 50 and 60, measured according to ASTM D2240.

[0014] According to one embodiment, the panel has beveled corners, with shock absorbers installed in the housing, sandwiched between said corners and the shell.

[0015] According to one embodiment, the junctions between the peripheral edge and the main wall of the hull are right-angled edges.

[0016] According to one embodiment, the shell has a thickness between 1 mm and 10 mm, preferably between 1.5 mm and 4 mm.

[0017] According to one embodiment, a drainage film is installed in the housing, between the main wall of the shell and the main face of the panel positioned against said main wall.

[0018] According to one embodiment, the main wall of the shell incorporates electric heating elements.

[0019] According to one embodiment, the main wall of the shell further integrates temperature sensors whose data are used by a temperature controller to adjust the heating temperature of the electric heating elements.

[0020] Another aspect of the invention relates to a method of manufacturing the formwork device defined above, comprising the following steps: - recovering a used formwork panel; - recalibrating the dimensions of the used panel according to the thickness of the shell; - associating the recalibrated panel with the shell.

[0021] According to one embodiment, the association of the recalibrated panel to the shell is achieved by thermoforming or molding said shell onto said panel.

[0022] According to one embodiment, the process further includes a recycling step consisting of: - recovering the formwork device whose protective shell is damaged after several uses; - removing the damaged protective shell from the panel; - installing a new protective shell on said panel. Brief description of the figures

[0023] Other advantages and features of the invention will become more apparent from the description of the embodiments which will follow, with reference to the attached drawings, made by way of indicative and non-limiting examples and on which: [Fig.1] is an exploded view of a formwork device according to the invention. [Fig.2] shows a formwork device according to the invention in a state where the protective shell is assembled to the formwork panel. [Fig. 3] is a cross-sectional view illustrating an assembly step of a protective shell and a formwork panel according to a first embodiment. [Fig. 4] is a cross-sectional view of the formwork system obtained after the assembly of [Fig. 3]. [Fig.5] is a cross-sectional view illustrating an assembly step of a protective shell and a formwork panel according to a second embodiment. [Fig.6] is a cross-sectional view of the formwork device obtained after the assembly of [Fig.5]. [Fig.7] is a cross-sectional view of a formwork device according to a third embodiment. [Fig.8] is a cross-sectional view of a formwork device according to a fourth embodiment. [Fig.9] is a longitudinal cross-sectional view of the formwork device according to the fourth embodiment. [Fig. 10] is a longitudinal cross-sectional view of the formwork device according to a fifth embodiment. [Fig.l 1] is a cross-sectional view of a formwork device according to a sixth embodiment. [Fig. 12] illustrates the setting up of two formwork devices according to the invention for pouring a floor. [Fig. 13] illustrates a recalibration step of a used formwork panel. Description of the implementation methods

[0024] As used herein, unless otherwise indicated, the possible use of the ordinal adjectives "first," "second," etc., to describe an object simply indicates that different occurrences of similar objects are mentioned and does not imply that the objects thus described must be in any given sequence, whether in time, space, ranking, or any other way. "X and / or Y" means: X alone or Y alone or X+Y. Generally speaking, it will be appreciated that in the various accompanying drawings, the objects are drawn arbitrarily to facilitate their interpretation.

[0025] The formwork device that is the subject of the invention is intended for use in the technical sector of construction and / or civil engineering, for the formation of structures, preferably for the production of concrete slabs or floors. However, it can also be used for the construction of walls, pillars, columns, or other structures. It can also be used for temporary stage flooring, protected pedestrian access, scaffolding platforms, etc.

[0026] With reference to [Fig.1], the device 1 consists of a formwork panel 2 assembled to a removable protective shell 3.

[0027] The panel 2 is made of a wood-based material, preferably of a material from the following family: plywood, OSB (for the English acronym for "Oriented Strand Board" and composed of oriented wood strands), chipboard, wood, which are the materials commonly used for the production of formwork panels.

[0028] The panel 2, generally rectangular in shape, is delimited by two principal faces 20, 21 and lateral edges 23. The lateral edges 23 are straight and perpendicular to the two principal faces 20, 21, which are flat and parallel to each other. According to an advantageous embodiment, the panel 2 has a length between 80 cm and 250 cm, a width between 40 cm and 180 cm, and a thickness between 5 mm and 30 mm.

[0029] The protective shell 3 has a general rectangular parallelepiped shape. Referring to Figures 1, 2, 3, and 4, it comprises a peripheral rim 30 and a main wall 31 forming a single-piece structure that defines a recess 32 into which the panel 2 is intended to be inserted. The rim 30 consists of four straight lateral edges perpendicular to the main wall 31, at least the outer face 311 of which is flat. In an advantageous embodiment, the shell 3 has a length of between 90 cm and 260 cm, a width of between 40 cm and 190 cm, and a height of between 8 mm and 30 mm.

[0030] Referring to [Fig. 4], when panel 2 is inserted into the housing 32, the peripheral edge 30 covers and removably encloses the lateral edges 23 of panel 2. The main wall 31, and more specifically its inner face 310, is positioned against the main face 20 of panel 2. The outer face 311 of the main wall 30 forms a flat and smooth formwork face, as explained further in the description. In the assembled configuration of Figures 2 and 4, the other main face 21 of panel 2 is located in the same plane as the distal end of the peripheral edge 30, so that the device 1 has a general rectangular parallelepiped shape.

[0031] The shell 3 thus envelops the panel 2, to protect it against wear, shocks and damage caused by handling, installation and demolding operations.

[0032] To withstand the rigorous conditions of construction sites, particularly abrasion caused by concrete aggregates during pouring, screeding, and / or degassing by vibration, as well as impacts and damage, the shell 3 is made of a plastic material, advantageously an elastomeric or thermoplastic material, preferably a recyclable material. Suitable elastomers for the shell 3 include, but are not limited to, polyurethane, natural rubber, synthetic rubber such as silicone, nitrile rubber (NBR), styrene-butadiene rubber (SBR), or chloroprene rubber (neoprene). These materials offer sufficient elasticity to facilitate the installation and removal of the shell 3, while ensuring adequate protection of the panel 2. The shell 3 can also be made from thermoplastic materials such as polypropylene (PP) or high-density polyethylene (HDPE).PP and HDPE provide increased rigidity to shell 3 and good moisture resistance. To further facilitate the device's recycling process, shell 3 can also be manufactured from recyclable materials such as recycled PP, recycled HDPE, or recycled thermoplastic polyurethanes (TPU).

[0033] According to one embodiment, the plastic material used has a Shore A hardness between 45 and 70, advantageously between 50 and 60, measured in accordance with ASTM D2240 (version in force on the date of filing of this application), in particular by means of a durometer. This hardness range offers a good compromise between the flexibility and rigidity of the shell 3 with good shock and / or vibration absorption capacity. Furthermore, within this hardness range, when the devices are butted together to form the formwork structure (as illustrated in [Fig. 12]), the shells 3 provide excellent sealing when in contact.

[0034] According to one embodiment, the thickness of the shell 3, i.e., the thickness of the peripheral edge 30 and the main wall 31, is advantageously between 1 mm and 10 mm, preferably between 1.5 mm and 4 mm. This thickness provides effective protection against impacts and shocks, reducing the risk of damage to the underlying panel 2. This thickness range also contributes to the longevity of the shell 3 by resisting wear, abrasion, and deformation, thus increasing the overall service life of the formwork system. Furthermore, this thickness range maintains sufficient flexibility in the shell 3 to easily adapt to any irregularities in the panel 2, facilitating its installation and removal.

[0035] According to the embodiment shown in Figures 5 and 6, the peripheral edge 30 of the shell 3 comprises one or more internal ribs 300 projecting into the housing 32. Each rib 300 is configured to engage in a complementary groove 230 formed on at least one lateral edge 23 of the panel 2. This or these ribs 300 are arranged on the inner face of the peripheral rim 30. Each rib 300 can extend continuously or discontinuously around the entire periphery of the rim 30, that is, along each of its lateral edges, or only along some of them. The groove(s) 230 follow the same configuration. This design improves the mechanical retention of the shell 3 on the panel 2, preventing relative movement or slippage of said shell with respect to said panel and reducing the risk of misalignment during handling or use of the device. This rib-groove system also guarantees precise and repeatable positioning of the shell 3.Furthermore, the engagement between the rib(s) 300 and the groove(s) 230 helps improve the seal around the edges 23 of the panel 2, reducing the risk of concrete and / or fluid and / or debris seeping in, which could otherwise compromise the assembly or the integrity of the formwork system. This prevention of seepage is optimal when at least one rib 300 is located at the distal end of the peripheral edge 30.

[0036] In addition to or as a substitute for the rib-groove system, and as illustrated in [Fig.7], the peripheral edge 30 of the shell 3 can be stapled to the lateral edges 23 of the panel 2 by means of staples 231. This quick and easy-to-implement fastening method makes it possible in particular to reduce the risks of displacement of the shell during use.

[0037] According to the embodiment of Figures 8 and 9, the panel 2 has beveled corners 24, with shock absorbers 4 installed in the housing 32, sandwiched between said corners and the shell 3. The bevels 24 are preferably made at the upper corners of the panel 2, i.e. the corners located at the main face 21 of said panel positioned against the main wall 31 of the shell 3. The absorbers 4 can, for example, be made of rubber, silicone, ethylene-vinyl acetate (EVA), foam, or reinforced nylon.

[0038] The corners 24 of panel 2, being the most vulnerable points, are thus protected by the absorbers 4. The risks of chipping, cracking, or premature wear are thereby reduced, thereby increasing the service life of panel 2. The absorbers 4 also allow for a more uniform distribution of mechanical stresses around the corners of the panel, preventing localized stresses that could affect the structural integrity of panel 2. Finally, these absorbers 4 can compensate for slight dimensional variations of the panel and the housing 32, thus contributing to maintaining the correct position of the shell 3.

[0039] According to the embodiment of [Fig. 10], a drainage film 5 is installed in the housing 32, between the main wall 31 of the shell 3 and the main face 20 of the panel 2 positioned against said main wall. It preferably covers the entire main face 20 and, where applicable, all or part of the lateral edges 23. This drainage film 5 prevents moisture from accumulating between the shell 3 and the panel 2, thus protecting the panel from mold, swelling, and other types of damage caused by prolonged exposure to moisture. It also forms an insulating layer that helps maintain stable thermal conditions, improving the concrete curing process. The film 5 can be made of materials such as nylon, geotextile, or polyethylene foam.

[0040] According to the embodiment of [Fig. 11], the main wall 31 of the shell 3 incorporates electric heating elements 312. These heating elements may be in the form of electric resistors or heating plates or films. They may be directly integrated into the main wall 31 or attached to it. The heating elements 312 are preferably arranged homogeneously over the entire surface of the main wall 31 to ensure uniform heat distribution over the entire surface of the formwork.

[0041] The heating elements 312 maintain an optimal temperature for the formwork system to accelerate the concrete hardening process and reduce the required stripping time. This is particularly advantageous when the system is used in cold climatic conditions and / or to provide flexibility in work planning based on weather conditions and site deadlines.

[0042] According to a preferred embodiment, the main wall 31 of the shell 3 further incorporates temperature sensors 313, the data from which are used by a temperature controller 314 to adjust the heating temperature of the heating elements 312. The controller 314 can be integrated into the shell 3 or located remotely from it. This temperature control makes it possible to adjust the heat according to the specific requirements of the concrete and the environmental conditions. It also makes it possible to understand and analyze the reaction dynamics of the concrete. Temperature regulation during the hardening process also contributes to obtaining a concrete structure with more uniform and higher-quality mechanical properties, reducing the risk of cracking and imperfections.

[0043] The shell 3 can be obtained by molding or injection and attached to the panel 2. The shell 3 can also be directly thermoformed or molded onto the panel 2 so as to create a shell that precisely conforms to the contours of said panel and minimizes gaps that could allow leaks. Another advantage of thermoforming or molding onto the panel is that it allows the shell 3 to adapt perfectly to the geometry of said panel, regardless of any imperfections in the latter. The mechanical connection between the two elements is also improved, so as to eliminate the need for the aforementioned mechanical fasteners.

[0044] Referring to [Fig. 12], in use, the devices 1 are butted together to form the formwork structure onto which the concrete 6 is poured. For floor or slab formwork, the devices 1 are installed so that the formwork faces 311 are in the same plane. The edges 30 of the adjacent devices are in contact to ensure excellent sealing.

[0045] For each device 1, the junctions between the peripheral edge 30 and the main wall 31 of the shell 3 are preferably right-angled edges, rather than beveled or curved edges. This feature ensures a precise fit and a clean joint between the different parts of the formwork, minimizing interstitial spaces in the formwork surface. It also allows for clean alignment of the panels and optimized formwork flatness. This feature thus contributes to significantly reducing the finishing work required on the concrete surface after formwork removal.

[0046] According to a preferred method of manufacturing the formwork device, panel 2 is a used, conventional formwork panel that is recovered, and more specifically a panel too damaged for conventional reuse. The dimensions of this panel are recalibrated according to the thickness of the shell 3. This recalibration step can, for example, be carried out by sawing and / or sanding the used panel.

[0047] One objective of this recalibration step may be to ensure that the formwork device has the same dimensions as a traditional formwork panel. For example, if a traditional panel has a length of 250 cm, a width of 125 cm, and a thickness of 15 mm, the "shell + recalibrated panel" combination must have these same dimensions. Assuming that the shell 3 has a thickness of 3 mm (peripheral edge thickness = main wall thickness = 3 mm), the used panel is recalibrated to have the following dimensions: length of 249.4 cm (250 cm - 2 x 3 mm), width of 124.4 cm (125 cm - 2 x 3 mm), thickness of 12 mm (15 mm - 3 mm).

[0048] It may also be desirable for the formwork device to have different dimensions than a traditional formwork panel, for example a length of 200 cm, a width of 100 cm and a thickness of 15 mm. In this case, if the traditional panel used has a length of 250 cm, a width of 125 cm and a thickness of 15 mm, it is recalibrated to have the following dimensions: length of 199.4 cm (200 cm - 2x3 mm), width of 99.4 cm (100 cm - 2x3 mm), thickness of 12 mm (15 mm - 3 mm).

[0049] Referring to [Fig. 13], the recalibration step (illustrated by the dotted lines) also makes it possible to remove, or at least reduce, the damaged parts 26' of the used panel 2' so as to obtain a recalibrated panel 2 in the best possible condition. This recalibrated panel 2 can then be joined to the shell 3 according to the techniques explained in detail previously, preferably by thermoforming or molding of said shell onto said panel.

[0050] After several uses of the formwork device, the shell 3, and more specifically its formwork face 311, may be damaged due to the conditions to which it is exposed on construction sites. A damaged formwork face 311 can then lead to the appearance of surface defects on the concrete, such as irregularities or roughness requiring refinishing after formwork removal. In this case, the device is recovered and the damaged shell 3 is removed from the panel 2. A new protective shell is then simply installed on the panel.

[0051] By reusing existing panels and replacing only their damaged protective casing, the panels' lifespan is extended, rather than sending the entire assembly to landfill. By reintegrating the formwork panels into the production cycle after a simple casing replacement, it is possible to maintain long-term formwork quality and performance, while offering a cost-effective and environmentally friendly solution.

[0052] The arrangement of the various elements and / or means and / or steps of the invention, in the embodiments described above, should not be understood as requiring such an arrangement in all implementations. In any event, it will be understood that various modifications may be made to these elements and / or means and / or steps, without departing from the spirit and scope of the invention.

[0053] Furthermore, one or more features described only in one embodiment can be combined with one or more other features described only in another embodiment. Similarly, one or more features described only in one embodiment can be generalized to other embodiments, even if this or these features are described only in combination with other features.

Claims

Demands

1. Formwork device comprising a formwork panel (2) made of a wood-based material and delimited by two main faces (20, 21) and lateral edges (23), characterized in that a removable protective shell (3) made of plastic material is associated with said panel, said shell comprising: • a peripheral edge (30) configured to cover and enclose in a removable manner the lateral edges (23) of the panel (2), • a main wall (31) configured to be positioned against a main face (20) of the panel (2), which main wall comprises an external face (311) forming a formwork face, • the main wall (31) and the peripheral edge (30) forming a monobloc structure delimiting a housing (32) into which the panel (2) is inserted.

2. Device according to claim 1, wherein the peripheral edge (30) of the shell (3) comprises at least one internal rib (300) projecting into the housing (32), which rib is configured to engage in a complementary groove (230) provided on at least one lateral edge (23) of the panel (2).

3. Device according to any one of the preceding claims, wherein the peripheral edge (30) of the shell (3) is stapled to the lateral edges (23) of the panel (2).

4. Device according to any one of the preceding claims, wherein the shell (3) is made of a plastic material having a Shore A hardness of between 45 and 70, advantageously between 50 and 60, measured according to ASTM D2240.

5. Device according to any one of the preceding claims, wherein the panel (2) has beveled corners (24), shock absorbers (4) being installed in the housing (32), sandwiched between said corners and the shell (3).

6. Device according to any one of the preceding claims, wherein the junctions between the peripheral edge (30) and the main wall (31) of the shell (3) are right-angled edges.

7. Device according to any one of the preceding claims, wherein the shell (3) has a thickness of between 1 mm and 10 mm, preferably between 1.5 mm and 4 mm.

8. Device according to any one of the preceding claims, wherein a draining film (5) is installed in the housing (32), between the main wall (31) of the shell (3) and the main face (20) of the panel (2) positioned against said main wall.

9. Device according to any one of the preceding claims, wherein the main wall (31) of the shell (3) incorporates electric heating elements (312).

10. Device according to claim 9, wherein the main wall (31) of the shell (3) further integrates temperature sensors (313) whose data are used by a temperature controller (314) to adjust the heating temperature of the electric heating elements (312).

11. Method of manufacturing the formwork device according to claim 1, comprising the following steps: • recover a used formwork panel (2'), • recalibrate the dimensions of the used panel (2') according to the thickness of the shell (3), • associate the recalibrated panel (2) with the shell (3).

12. Method according to claim 11, wherein the association of the recalibrated panel (2) with the shell (3) is achieved by thermoforming or molding said shell onto said panel.

13. A method according to any one of claims 11 or 12, further comprising a recycling step consisting of: • recovering the formwork device (1) whose protective shell (3) is damaged after several uses, • removing the damaged protective shell (3) from the panel (2), • installing a new protective shell on said panel.

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