CONCRETE FORMWORK PANEL

Abstract

CONCRETE FORMWORK PANEL Panel (2) for concrete formwork, particularly for concrete slab formwork, comprising: - a honeycomb panel (1) made of plastic material including a first layer (1a) extending along a first plane (P1) and a second layer (1b) extending along a second plane (P2) parallel to the first plane (P1), the first (1a) and second (1b) layers being connected to each other by walls extending perpendicularly to the first (P1) and second (P2) planes and forming cells, - a peripheral edge (5) covering the entire peripheral edge of the honeycomb panel (1), said peripheral edge (5) being made of a thermoplastic elastomer of lower hardness than the hardness of the first (1a) and second (1b) layers of the honeycomb panel (1). Figure to be published with the abbreviation: Fig. 7

Description

Title of the invention: PANEL FOR CONCRETE FORMWORK TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to the field of construction, and more particularly to a panel for concrete formwork.

[0002] For formwork of concrete, in particular for the manufacture of concrete slabs, support structures for a slab formwork or similar are used as described in documents FR 2 900 176 B1 and FR 2 923 241 Bl. On such structures are generally placed plywood panels intended to form a smooth and continuous horizontal surface onto which the concrete is poured in liquid form.

[0003] After the concrete has reached strength, the support structure of a slab formwork or similar and the plywood panels are removed to be reused to form another concrete slab or similar.

[0004] As they are reused, the wood plywood panels are subjected to impacts that damage their peripheral edges to the point where it is sometimes no longer possible to ensure sufficient surface continuity between two adjacent wood plywood panels. The wood plywood panels are then discarded but unfortunately cannot be easily recycled due to the glue they contain, as well as the phenolic varnish that coats their main faces to limit their adhesion to concrete after they have reached strength. In addition, the wood plywood panels are quite heavy, making the work of the operators very arduous. Description of the invention

[0005] One problem proposed by the present invention is to provide a panel for concrete formwork that is easier to handle and easier to recycle, while limiting the risks of damage to the peripheral edge of said panel.

[0006] To achieve these and other objectives, the invention proposes a panel for concrete formwork, in particular for concrete slab formwork, comprising: - a honeycomb plate made of plastic material comprising a first layer extending along a first plane and a second layer extending along a second plane parallel to the first plane, the first and second layers being connected to each other by walls extending perpendicularly to the first and second planes and forming cells, - a peripheral border covering the entire peripheral edge of the honeycomb plate, said peripheral border being made of a thermoplastic elastomer of lower hardness than the hardness of the first and second layers of the honeycomb plate.

[0007] The honeycomb panel provides both rigidity and lightness, while the peripheral edge protects the peripheral edge of the honeycomb panel and provides satisfactory continuity with an adjacent panel. The lower hardness of the peripheral edge allows for its reversible and preferential deformation, which helps to limit the risk of damaging the honeycomb panel during handling for concrete formwork.

[0008] Advantageously, the honeycomb plate can be made of polypropylene, which is a reasonably priced material and is easily recyclable.

[0009] Preferably, the peripheral edge can be made of a thermoplastic elastomer based on polyolefins. Again, this is a reasonably priced material that is easily recyclable.

[0010] It should be noted that when the honeycomb panel is made of polypropylene and the peripheral edge is made of a thermoplastic elastomer based on polyolefins, the concrete formwork panel can be easily recycled without having to separate the honeycomb panel from the peripheral edge. The concrete formwork panel can thus be recycled by grinding it in one piece and reusing the ground material without having to separate the materials.

[0011] Advantageously, the peripheral edge can have a hardness between 50 Shore A and 90 Shore A. A hardness below 50 Shore A makes manufacturing the peripheral edge by injection molding very difficult, and a hardness above 90 Shore A is too high for sufficient deformability of the peripheral edge to adequately protect the dimpled plate. The hardness is measured at normal laboratory temperature (23°C ± 2°C).

[0012] Preferably, on each side of the honeycomb plate, the material constituting the peripheral edge fills at least partially a plurality of cells. Such filling provides reliable bonding of the peripheral edge along each side of the honeycomb plate.

[0013] The cells may advantageously be arranged in a staggered pattern and / or each have a closed contour (for example, hexagonal or substantially circular) providing undercut volumes along at least one side of the honeycomb plate, and preferably along several sides of the honeycomb plate. The cells may thus form a honeycomb structure.

[0014] Preferably, the peripheral border may extend radially away from the honeycomb plate by a distance of between 5 mm and 15 mm. The border peripheral, which preferably has a thickness equal to the thickness of the panel, thus provides satisfactory shock absorption capabilities by elastic deformation.

[0015] Advantageously, the first layer and / or the second layer may comprise a mineral filler, preferably talc. Such a mineral filler increases the mechanical properties of the honeycomb plate.

[0016] Preferably, the first and / or second layer may include a fibrous filler, preferably glass fiber. Such a fibrous filler increases the rigidity of the honeycomb panel, particularly to limit the risk of excessive deflection under the weight of the concrete.

[0017] Advantageously, the panel can have a thickness of between 9 mm and 30 mm. Such a thickness can be equal to the usual thickness of adjacent wood plywood panels with through-holes to provide technical passages in the concrete formwork.

[0018] Preferably, the first and second layers of the honeycomb plate can each have a thickness between 0.8 mm and 1.5 mm.

[0019] Advantageously, the peripheral edge may include an identification data carrier, preferably embedded within the peripheral edge, capable of communicating with a data reader device. This identification data carrier may preferably be of the RFID or NFC type. Such a data carrier provides reliable identification of the panel, enabling panel tracking (entry into stock, exit from stock, etc.) in order to assess its potential wear. Embedding this data carrier within the peripheral edge, particularly during the injection molding of said peripheral edge, makes it inseparable from the panel and prevents damage to the corrugated board.

[0020] According to another aspect of the present invention, a method for manufacturing a panel as previously described is proposed; during said manufacturing process, the material constituting the peripheral border can be injected hot under pressure into a mold surrounding the peripheral edge of the honeycomb plate.

[0021] Such an injection process makes it possible to create a strong adhesion between the honeycomb plate and the peripheral border, to effectively limit any risk of separation.

[0022] By adjusting the temperature and / or pressure of the peripheral rim material during its injection, it is possible to promote the penetration of the peripheral rim material through a portion of the cell walls. The peripheral rim material can thus at least partially fill cells belonging to a row of cells located beyond the row of cells immediately adjacent to the sides.

[0023] Very good results have been obtained by stipulating that: - the honeycomb plate is made of polypropylene, - the constituent material of the peripheral border is a thermoplastic elastomer based on polyolefins, but preferably excluding thermoplastic elastomers based on polyurethane, and thermoplastic elastomers based on styrene.

[0024] During the manufacturing process, the mold can advantageously be cooled during the injection of the thermoplastic elastomer, preferably by means of a fluid. Such cooling helps to limit the risk of deformation of the first and second layers of the honeycomb plate.

[0025] During the manufacturing process, the identification data carrier can preferably be placed in a space between the peripheral edge of the honeycomb plate and the injection mold before the peripheral rim material is injected. The identification data carrier is thus embedded in the peripheral rim material, making it inseparable from the peripheral rim (and the panel) and also visually undetectable. SUMMARY DESCRIPTION OF THE DRAWINGS

[0026] Other objects, features and advantages of the present invention will become apparent from the following description of particular embodiments, made in relation to the accompanying figures, among which:

[0027] [Fig-1] Fig. 1 is a schematic perspective view of a honeycomb plate used for the manufacture of a particular embodiment of a panel according to the present invention;

[0028] [Fig.2] Fig.2 is a partial top view of the honeycomb plate of Fig.1

[0029] [Fig.3] The [Fig.3] is a partial and side view of the honeycomb plate of the [Fig.1];

[0030] [Fig.4] Fig.4 is a top view partially illustrating the arrangement of the honeycomb plate of the [Fig.l] in an injection mold;

[0031] [Fig.5] The [Fig.5] is a top view of a panel comprising the honeycomb plate of the [Fig.1] in said injection mold after injection of a peripheral border;

[0032] [Fig.6] [Fig.6] is a partial cross-sectional view of the panel of [Fig.5]; and

[0033] [Fig.7] Fig.7 is a perspective view of a panel according to a mode of particular embodiment of the present invention;

[0034] [Fig. 8] [Fig. 8] is a perspective and detail view of the panel in [Fig. 7]. DESCRIPTION OF PREFERRED EMBODIMENT METHODS

[0035] When identical numerical references are used in several figures, embodiments or variants of the invention, these numerical references designate identical or similar elements in each of the figures, embodiments or variants.

[0036] Figures 1 to 3 illustrate a honeycomb panel 1 intended for use in the manufacture of a panel 2 according to the invention (Figures 7 and 8) for concrete formwork, in particular for concrete slab formwork. The honeycomb panel 1 has a rectangular shape with four sides 8 to 11 and can, in particular, be obtained by the manufacturing process described in document WO 2006 / 053407 A1, for example.

[0037] The honeycomb plate 1 is made of plastic (polypropylene, for example) and comprises a first layer 1a extending along a first plane PI and a second layer 1b extending along a second plane P2 parallel to the first plane PI ([Fig. 3]). The first 1a and second 1b layers are connected to each other by walls 3 extending perpendicularly to the first PI and second P2 planes and forming cells 4.

[0038] In [Fig. 2], the walls 3 and cells 4 are shown in dotted lines because they are hidden by the first layer la. In the figures, only part of the walls and cells are identified by the numerical references 3 and 4 so as not to hinder the reader's understanding.

[0039] The 4 cells are arranged in a staggered pattern. Each one has a closed contour which is hexagonal here (other contour shapes could be considered, circular for example).

[0040] Here, the 4 cells form a honeycomb structure.

[0041] In addition to a honeycomb plate 1, the panel 2 according to the invention (Figures 7 and 8) comprises a peripheral border 5 covering the entire peripheral edge of the honeycomb plate 1. The peripheral border 5 is made of a thermoplastic elastomer of lower hardness than the hardness of the first 1a and second 1b layers of the honeycomb plate 1.

[0042] Preferably, the peripheral border 5 is made of a thermoplastic elastomer based on polyolefins (but preferably excluding thermoplastic elastomers based on polyurethane, and thermoplastic elastomers based on styrene), while the honeycomb plate 1 is made of polypropylene.

[0043] The peripheral rim has a hardness between 50 Shore A and 90 Shore A, to ensure a good compromise between the injectability of the material constituting the peripheral rim 5 and the deformability of the peripheral rim 5 in order to adequately protect the perforated plate 1 against impacts. The hardness measurement is carried out at normal laboratory temperature (23 °C ± 2 °C).

[0044] To increase the mechanical properties of the honeycomb plate 1, the first layer 1a and / or the second layer 1b comprise a mineral filler, preferably talc.

[0045] To increase the rigidity of the honeycomb plate 1, in particular to limit the risks of excessive deflection under the weight of the concrete, the first layer 1a and / or the second layer 1b comprise a fibrous filler, preferably glass fiber.

[0046] As can be seen more clearly in [Fig.3], the honeycomb plate 1 has a thickness e (which is the same as that of the peripheral border 5 and therefore of the panel 2) between 9 mm and 30 mm.

[0047] The first 1a and second 1b layers of the honeycomb plate 1 have respective thicknesses ela and elb between 0.8 mm and 1.5 mm. The thicknesses ela and elb are preferably equal.

[0048] The manufacture of panel 2 is more particularly illustrated in figures 4 to 6.

[0049] As illustrated in [Fig.4], the honeycomb plate 1 is placed in a mold 6 which surrounds the peripheral edge of the honeycomb plate 1. A space E is maintained at the periphery of the peripheral edge of the honeycomb plate 1.

[0050] The space E extends radially away from the honeycomb plate 1 by a distance D between 5 mm and 15 mm, and the honeycomb plate 1 has a thickness of at least 7 mm. The peripheral edge 5 thus has a cross-section of at least 5 mm x 7 mm along the sides 8 to 11 of the honeycomb plate 1.

[0051] The mold 6 has lugs 6a and 6b, projecting towards the peripheral edge of the honeycomb plate 1, and intended to create grooves 7a and 7b ([Fig.7]) allowing the panel 2 to be gripped by a tool to pull the panel 2 in order to detach it from the concrete after solidification (rise in strength).

[0052] Due to the cutting of the contour of the honeycomb plate 1: - along side 8 of the honeycomb plate 1, one out of every two cells 4 (namely cells 4a to 4e) has a cross-section (along a plane intermediate to the first PI and second P2 planes) open on the peripheral edge of the honeycomb plate 1 and having undercuts, - along side 9 of the alveolar plate 1, all the alveoli 4 (here 4a' to 4g') have a cross-section (along a plane intermediate to the first PI and second P2 planes) open on the peripheral edge of the alveolar plate 1 but not having undercuts.

[0053] The alveoli 4 along side 10 (opposite side 8 in [Fig.1]) have a configuration similar to that of the alveoli along side 8. The alveoli along side 11 (opposite side 9 in [Fig.1]) have a configuration similar to that of the alveoli along side 9.

[0054] It should be noted that the presence or absence of undercuts in the cells 4 depends on the relative position and orientation of the cutting lines made to cut the honeycomb plate 1 with respect to the structure formed by the cells 4.

[0055] Optionally, an identification data carrier 12 (preferably of the RFID or NFC type) is placed in the space E between the peripheral edge of the honeycomb plate 1 and the injection mold 6 before injection of the constituent material of the peripheral border 5.

[0056] After closing the mold 6, the material (thermoplastic elastomer) constituting the peripheral border 5 is injected hot under pressure into the mold 6 surrounding the peripheral edge of the honeycomb plate 1. The material constituting the peripheral border 5 then fills the space E ([Fig.5]).

[0057] Under the effect of heat, a strong adhesion is created of the peripheral edge 5 to the first layer 1a and / or to the second layer 1b and / or to the walls 3 of the cells 4.

[0058] The mold 6 is preferably cooled by fluid during the injection of the thermoplastic elastomer, in order to limit the risks of deformation of the first 1a and second 1b layers of the honeycomb plate 1.

[0059] The [Fig.6] is a cross-sectional and top view of a panel 2 after injection of the peripheral border 5, said cross-section being carried out along an intermediate plane between the first PI and second P2 planes.

[0060] It can be seen in this figure that, on each side of the honeycomb plate 1, the material constituting the peripheral border 5 fills at least partially a plurality of cells 4.

[0061] More specifically, it can be seen in [Fig. 6] that the constituent material of the peripheral border 5 has, in particular: - filled cells 4a and 4e without affecting walls 3 of the latter, - melting of the walls 3 of the cells 4b, 4c and 4d and at least partially filling of the adjacent cells 4 in which the constituent material of the peripheral border 5 forms, after solidification, undercut shapes, - melted half of the walls of cells 4a' and 4b', - melted the walls 3 of the cells 4c', 4e' and 4g' and at least partially filled adjacent cells 4 in which the constituent material of the peripheral border 5 forms undercut shapes after solidification.

[0062] The undercuts formed by the peripheral edge 5 in the alveoli 4 provide a very strong anchorage of the peripheral edge 5 to the alveoli plate 1.

[0063] By adjusting the temperature and / or pressure of the material constituting the peripheral rim 5 during its injection, it is possible to promote the passage of the material constituting the peripheral rim 5 through a portion of the walls 3. The material constituting the peripheral rim 5 can thus at least partially fill the cells 4 of a row of cells 4 located beyond the row of cells immediately adjacent to the sides 8 to 11. However, it is important not to choose a temperature and / or too high a pressure so as not to excessively damage the honeycomb structure of the honeycomb plate 1 and so as not to deform the first 1a and second 1b layers which must remain as flat as possible.

[0064] Figure 6 also shows that the lugs 6a and 6b have created grooves 7a and 7b, allowing a tool to grip panel 2 and pull it away from the concrete after it has solidified. Other grooves 7c to 71 have been similarly formed in the peripheral edge 5 (Figure 7).

[0065] The identification data carrier 12 is embedded in the constituent material of the peripheral border 5 and is therefore invisible and inseparable from the peripheral border 5 and the panel 2.

[0066] The resulting panel 2 ([Fig.7]) is both lightweight, offers sufficient rigidity to support concrete during formwork (of a slab in particular), and exhibits good durability due to its peripheral edge 5 made of thermoplastic elastomer.

[0067] The present invention is not limited to the embodiments that have been explicitly described, but includes the various variants and generalizations contained within the scope of the following claims.

Claims

Demands

1. Panel (2) for concrete formwork, in particular for concrete slab formwork, comprising: - a honeycomb plate (1) of plastic material comprising a first layer (la) extending along a first plane (PI) and a second layer (1b) extending along a second plane (P2) parallel to the first plane (PI), the first (la) and second (1b) layers being connected to each other by walls (3) extending perpendicularly to the first (PI) and second (P2) planes and forming cells (4), - a peripheral edge (5) covering the entire peripheral edge of the honeycomb plate (1), said peripheral edge (5) being made of a thermoplastic elastomer of lower hardness than the hardness of the first (la) and second (1b) layers of the honeycomb plate (1).

2. Panel (2) according to claim 1, characterized in that the honeycomb plate (1) is made of polypropylene.

3. Panel (2) according to any one of claims 1 or 2, characterized in that the peripheral edge (5) is made of a thermoplastic elastomer based on polyolefins.

4. Panel (2) according to any one of claims 1 to 3, characterized in that the peripheral edge (5) has a hardness between 50 Shore A and 90 Shore A.

5. Panel (2) according to any one of claims 1 to 4, characterized in that, on each side of the honeycomb plate (1), the material constituting the peripheral border (5) fills at least partially a plurality of cells (4).

6. Panel (2) according to any one of claims 1 to 5, characterized in that the peripheral edge (5) extends radially away from the honeycomb plate (1) by a distance (D) between 5 mm and 15 mm.

7. Panel (2) according to any one of claims 1 to 6, characterized in that the first layer (1a) and / or the second layer (1b) comprise a mineral filler, preferably talc.

8. Panel (2) according to any one of claims 1 to 7, characterized in that the first layer (the) and / or the second layer (1b) comprises a fibrous filler, preferably glass fiber.

9. Panel (2) according to any one of claims 1 to 8, characterized in that the panel (2) has a thickness (e) between 9 mm and 30 mm.

10. Panel (2) according to any one of claims 1 to 9, characterized in that the first (la) and second (1b) layers of the honeycomb plate (1) each have a thickness (ela, elb) between 0.8 mm and 1.5 mm.

11. Panel (2) according to any one of claims 1 to 10, characterized in that the peripheral edge (5) comprises an identification data carrier (12), preferably included in the peripheral edge (5), capable of communicating with a data reading device, said identification data carrier (12) preferably being of the RFID or NFC type.

12. A method of manufacturing a panel (2) according to any one of claims 1 to 11, wherein the material constituting the peripheral edge (5) is hot injected under pressure into a mold (6) surrounding the peripheral edge of the honeycomb plate (1).

13. A manufacturing method according to claim 12, wherein the thermoplastic elastomer is injected at a chosen temperature and pressure so that the thermoplastic elastomer at least partially fills cavities (4) forming part of a row of cavities (4) located beyond a row of cavities (4) immediately adjacent to peripheral sides (8-11) of the dimpled plate (1).

14. A manufacturing method according to any one of claims 12 or 13, wherein: - the honeycomb plate (1) is made of polypropylene, - the constituent material of the peripheral border (5) is a thermoplastic elastomer based on polyolefins, but preferably excluding thermoplastic elastomers based on polyurethane, and thermoplastic elastomers based on styrene.

15. A manufacturing method according to any one of claims 12 to 14, wherein the mold (6) is cooled during the injection of the thermoplastic elastomer, preferably by fluid.

16. A manufacturing method according to any one of claims 12 to 15 for manufacturing a panel (2) according to claim 11, characterized in that the identification data carrier (12) is placed in a space (E) between the peripheral edge of the honeycomb plate (1) and the injection mold (6) before injection of the constituent material of the peripheral border (5).

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