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Title:
PANEL FOR MAKING RETAINING WALLS OF FORMWORKS FOR CONCRETE CASTINGS, IN PARTICULAR FOR RETAINING FORMWORKS FOR MAKING CONCRETE SLABS OR THE LIKE AND PROCESS FOR MANUFACTURING SAID PANEL
Document Type and Number:
WIPO Patent Application WO/2019/186362
Kind Code:
A1
Abstract:
Panel for making retaining walls of formworks for concrete casting, in particular for retaining formworks for making concrete slabs or the like, which panel is composed of a base body composed of a plate-like element cut to size and having a perimetric edge surface along which perimetric edge surface a perimetric protection edge made of a plastic material is provided and wherein said perimetric protection edge is made in the form of single continuous piece. Object of the invention is also a retaining structure for formworks, in particular for formworks for slabs or the like, wherein the panels are made according to the aforesaid panel.

Inventors:
PASOTTI RUBENS (IT)
Application Number:
PCT/IB2019/052396
Publication Date:
October 03, 2019
Filing Date:
March 25, 2019
Export Citation:
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Assignee:
PASOTTI IND LEGNO (IT)
International Classes:
E04G9/05; E04G9/02
Domestic Patent References:
WO2012034156A12012-03-22
Foreign References:
DE2618366A11977-11-17
DE7704398U11978-03-02
AT414313B2007-01-15
Attorney, Agent or Firm:
KARAGHIOSOFF, Giorgio A. (IT)
Download PDF:
Claims:
CLAIMS

1. Panel for making retaining walls of formworks for concrete casting, in particular for retaining formworks for making concrete slabs or the like, which panel is composed of a base body composed of a plate-like element cut to size and having a perimetric edge surface along which perimetric edge surface a perimetric protection edge made of plastic material is provided and wherein,

said perimetric protection edge is made in the form of a continuous single piece.

2. Panel according to claim 1 , wherein the protection edge has a predetermined thickness defined as the measurement between the external surface of the protection edge and the surface in contact with the surface of the peripheral edge of the base and said thickness is not constant for at least some regions or for the whole longitudinal extension with respect to the longitudinal extension and/or to the transverse extension or perpendicular to one or both of the panel faces.

3. Panel according to claim 1 or 2, wherein the protection edge has at least in some regions or for its whole longitudinal extension one or more cavities that can be continuous and/or discontinuous.

4. Panel according to one or more of the preceding claims, wherein the mutual adhesion surfaces of the edge of the base body and of the protection edge are made as corresponding with each other and with a three-dimensional shape, that is with a non-rectilinear shape when seen in cross-section view.

5. Panel according to one or more of the preceding claims, wherein said mutual contact surfaces of the edge of the base body and of the protection edge are provided with one or more projections extending in a continuous or discontinuous manner for a part or for the whole extension of said surfaces and that are in the form of knurls longitudinally oriented with reference to the longitudinal extension of said surfaces and/or that are composed of longitudinal ribs or teeth projecting outwardly from the surface of the edge of the base body and engaging by shape coupling into corresponding recesses of the contact surface of the protection edge.

6. Panel according to claim 4 or 5, wherein the surface of the peripheral edge of the base body can be made with a wedge-like shape of the cross section, while the protection edge has a complementary and corresponding recessed groove which is shape coupled to the wedge- like shape of the surface of the edge of the base body.

7. Panel according to claim 6, wherein this wedge-like shape is symmetrical with reference to a median plane parallel at least to one face of the panel and/or the base body.

8. Panel according to one or more of preceding claims 5 to 7, wherein the wedge-like shape is beveled in a flat and rounded manner at the tip of the wedge and has a trapezium-like sectional shape, while the groove in the protection edge is made with a corresponding shape for a shape coupling between the surfaces of the edge of the panel body and the surfaces of the protection edge.

9. Panel according to one or more of claims 4 to 8, wherein one or more continuous or discontinuous longitudinal projecting ribs or a longitudinal knurl or indentation engaging by shape coupling in corresponding grooves of the contact surface of the protection edge are provided along the inclined surfaces and/or flat or curved beveled surfaces.

10. Panel according to one or more of the preceding claims, wherein the base body has perimetric edges oriented according to different directions and connecting with one another at corner regions, said corner regions being shaped according to a plan shape profile which is recessed with respect to the shape of the corner region defined by the rectilinear extensions incident to one another of the edges of the base body that have different directions with respect to each other, while the protection edge has a shape so that to complete the shape of the panel, filling a recessed region of the base body correspondingly to the corner region defined by the rectilinear extensions of the external surfaces of the portions of the protection edges provided on the panel sides having different directions and incident to one another.

11. Panel according to one or more of the preceding claims, wherein the base body at each corner region has a rounding with a predetermined radius of curvature, which rounding is recessed in direction of the center of the base body with respect to the tangent position of the curvature to the extensions of the two sides having directions incident to one another of the edge surface of the panel, connecting portions of the edge of the base body being provided for each of the ends of the curve of said rounded region that are divergent towards the outside and each of the connecting portions connects at a point of one of the two sides having directions incident to one another, which point is provided at a certain distance from the incidence point of said two sides.

12. Panel according to one or more of the preceding claims, wherein in the thicker regions of the protection edge at the recesses of the corner regions in the base body or in the optional recesses at intermediate points of the rectilinear sides, one or more through holes essentially oriented in a transverse manner, in particular perpendicularly to the panel faces, are provided in the protection edge.

13. Panel according to one or more of the preceding claims, wherein the thickness of the protection edge in the direction perpendicular to the surfaces of the panel is larger with respect to the thickness of the base body, the surfaces of the protection edge parallel to the surfaces of the faces of the base body connecting to these surfaces of the faces of the base body by means of inclined and/or flared portions so that to avoid steps or interruptions at the connecting regions.

14. Panel according to claim 13, wherein the surfaces parallel to the faces of the base body extend along a more external peripheral strip of the thickness of the protection edge in a direction parallel to the faces of the panel and have a smaller extension with respect to the inclined surfaces of the protection edge connecting to the surfaces of the faces of the base body, preferably for example ranging from 10% to 50% of the extension of the surfaces inclined in a direction perpendicular to the surfaces of the edge of the base body and parallel to the faces of the base body.

15. Method for manufacturing panels according to one or more of the preceding claims 1 to 14, which method provides the following steps: arranging a sized base body having a predetermined plan shape and a predetermined section shape of the surface of the peripheral edge;

applying, by injection molding, a protection edge to the peripheral edge of the sized body.

16. Method according to claim 15, wherein the making of one or more through or non-through holes in predetermined areas and with orientation essentially perpendicular to the faces of the panel is provided, which holes are made contemporaneously with the injection molding step or in a following processing step by material removal.

17. Method according to claim 15 or 16, wherein the step of making lightening cavities in the bulk of plastic material forming the protection edge is provided contemporaneously with the injection molding step.

18. Combination of at least one panel and one loadbearing structure for panels for making retaining walls for concrete casting, in particular for concrete slabs or the like, wherein the panel(s) are made according to one or more of claims 1 to 17, while the panels are arranged directly adjacent to one another and with the external surfaces of the protection edges in contact with each other, so that to form an essentially continuous retaining wall, without marks in the contact regions between adjacent panels and substantially holding the concrete bulk.

19. Combination according to claim 18, wherein the framework is of the type comprising a loadbearing structure composed of a plurality of supporting vertical posts of a combination of longitudinal beams and/or cross members parallel to one another and of supporting frames intended to rest with at least two opposite sides on two adjacent longitudinal members and/or cross members parallel to one another and on which frames a panel is respectively fastened in place, each frame being made with a shape essentially corresponding to the plan shape of a panel and the dimensions of the frames being smaller than the corresponding dimensions of the panels, while the panels are mounted on frames in positions so that to project on all sides and for a predetermined extent beyond the corresponding side of the panel, optionally in a symmetrical manner for sides of the panel opposite each other.

Description:
ILPA INDUSTRIA LEGNO PASOTTI S.r.l.

Panel for making retaining walls of formworks for concrete castings, in particular for retaining formworks for making concrete slabs or the like and process for manufacturing said panel

The invention concerns a panel for making retaining walls of formworks for concrete casting, in particular for retaining formworks for making concrete slabs or the like, which panel is provided along the whole peripheral edge with a perimetric protection profile made of plastic material and applied to the peripheral edge of the panel itself.

The retaining formworks for concrete casting are known and are formed by a plurality of panels which, together, form the retaining concrete walls of desired shape and size and which panels are mounted so that to form said retaining walls in a loadbearing structure.

The formworks are generally provided with a supporting metal structure in the form of frameworks composed of posts, longitudinal members and cross members, according to various geometries and on which the panels are arranged side by side to one another so that to form a continuous retaining wall of the concrete bulk.

Among the different types of structures, there is a first structure in which the panel is used independently and is applied in combination with hooks and other accessories that are coupled directly to the panel.

In a second use method, the panels are inserted in a metal frame which structurally works to resist to the thrusts of the casting bulk and to be able to be easily assembled so that to form large walls.

The first system is generally used for small non-repetitive works since the thrust of the casting is supported by the panel only.

The second system is the most used and widespread one, but has a non-positive characteristic which cannot currently be eliminated and which consists in the fact that the joining of the single metal frames leaves a strongly marked impression on the final concrete structure.

The document EP2488713 shows a panel for formworks with a protection edge which is composed of a base element comprising a perimetric edge surface and in which a protection edge, which is formed by two parts applied differently from one another to the main body and made of different material, is provided along said perimetric edge surface. The two edge parts are respectively provided one along the longitudinal edges of the panel and the other in the corner regions and are respectively composed of rectilinear listels applied by means of adhesives to the edge surface of said longitudinal sides of the base body and of a protection edge of the corner regions applied by injection molding. The two different protection edge parts connect to one another by means of adhesion at the head surfaces.

The base body is composed of a plate of material which can be of any type and of any material.

The main body can be constituted by natural or synthetic material, in particular plastic material and/or combinations of these materials and can have a single or multilayer structure.

The plate of the main body can be provided with protecting layers applied on one or both of the faces opposite said plate and which extend until connecting to the perimetric edges.

In substance, it is possible to use any type of single or multilayer plate of synthetic or natural materials or of a combination of the currently existing ones and having mechanical characteristics suitable for the stresses expected for the type of use for the main body, in particular for the making of the retaining walls of concrete slabs.

The protection edge has the main function of avoiding panel damages in case of fall and is advantageously provided with thicknesses referred to the extension in a direction perpendicular to the edge of the base body, which can be larger in the regions more at risk of damage, for example during the mounting operations, for example due to falls. These can cause deformations which can cause both openings in the retaining surface from which the concrete can seep and marks and signs in the finished concrete surface.

The invention aims to overcome the drawbacks described above and to achieve a panel for making retaining walls of formworks for concrete casting, in particular for retaining formworks for making concrete slabs or the like, which allows to achieve better performances in terms of resistance, less weight and better aesthetic results in the making of the slabs.

The invention achieves the aforesaid results with a panel for making retaining walls of formworks for concrete casting, in particular for retaining formworks for making concrete slabs or the like, which panel is composed of a base body composed of a plate-like element cut to size and having a perimetric edge surface along which perimetric edge surface a perimetric protection edge made of a plastic material is provided and wherein

said perimetric protection edge is made in the form of a continuous single piece.

According to an embodiment, the protection edge has a predetermined thickness defined as the measurement between the external surface of the protection edge and the surface in contact with the surface of the peripheral edge of the base and said thickness is not constant for at least some regions or for the whole longitudinal extension with respect to the longitudinal extension and/or to the transverse extension or perpendicular to one or both of the panel faces.

According to a further characteristic, the protection edge has at least in some regions or for its whole longitudinal extension one or more cavities that can be continuous and/or discontinuous.

These cavities have the triple function to reduce the bulk of material, by reducing the overall weight of the panel, to confer greater elasticity to the protection edge and to reduce the costs of materials thanks to material savings.

Still according to a further characteristic, the mutual adhesion surfaces of the edge of the base body and of the protection edge are made as corresponding with each other and with a three-dimensional shape, that is with a non-rectilinear shape when seen in cross-section view.

Still according to a further characteristic, said mutual contact surfaces of the edge of the base body and of the protection edge are provided with one or more projections extending in a continuous or discontinuous manner for a part or for the whole extension of said surfaces and that are in the form of knurls longitudinally oriented with reference to the longitudinal extension of said surfaces and/or that are composed of longitudinal ribs or teeth projecting outwardly from the surface of the edge of the base body and engaging by shape coupling into corresponding recesses of the contact surface of the protection edge.

With reference to a preferred embodiment, the surface of the peripheral edge of the base body can be made with a wedge-like shape of the cross section, while the protection edge has a complementary and corresponding recessed groove which is shape coupled to the wedge- like shape of the surface of the edge of the base body.

A variation provides that this wedge-like shape is symmetrical with reference to a median plane parallel at least to one face of the panel and/or the base body.

An embodiment variation provides that the wedge-like shape is beveled in a flat and rounded manner at the tip of the wedge and has a trapezium-like sectional shape, while the groove in the protection edge is made with a corresponding shape for a shape coupling between the surfaces of the edge of the panel body and the surfaces of the protection edge.

One or more continuous or discontinuous longitudinal projecting ribs or a longitudinal knurl or indentation engaging by shape coupling in corresponding grooves of the contact surface of the protection edge are provided along the inclined surfaces and/or flat or curved beveled surfaces.

Still according to a characteristic, when the base body has perimetric edges oriented according to different directions and connecting with one another at corner regions, said corner regions being shaped according to a plan shape profile which is recessed with respect to the shape of the corner region defined by the rectilinear extensions incident to one another of the edges of the base body that have different directions with respect to each other, while the protection edge has a shape so that to complete the shape of the panel, filling a recessed region of the base body correspondingly to the corner region defined by the rectilinear extensions of the external surfaces of the portions of the protection edges provided on the panel sides having different directions and incident to one another.

A preferred embodiment provides that the base body at each corner region has a rounding with a predetermined radius of curvature, which rounding is recessed in direction of the center of the base body with respect to the tangent position of the curvature to the extensions of the two sides having directions incident to one another of the edge surface of the panel, connecting portions of the edge of the base body being provided for each of the ends of the curve of said rounded region that are divergent towards the outside and each of the connecting portions connects at a point of one of the two sides having directions incident to one another, which point is provided at a certain distance from the incidence point of said two sides.

Therefore, the aforesaid embodiment provides that two peripheral edge portions of the base body, which have different orientations from one another, at each end have a terminal segment inclined inwardly towards the center of the base body, starting from a predetermined distance from the point of incidence of the ideal rectilinear extensions of said portions, so that the real point of incidence is moved inwardly towards the center of the base body, while the corner region of said point of incidence is rounded with a predetermined radius of curvature.

A preferred embodiment provides that the corner region is symmetric with reference to the bisector of the corner defined by the ideal extensions of the two portions of the base body sides having directions incident to one another.

Thanks to this implementation, at the corner region, the thickness of the protection edge in direction of the bisector of the corner region of the panel and which completes the base body by filling the region between the surface edge of the base body and the shape of the corner region defined by the extensions of the external surfaces of the protection edge at said corner region, is larger with respect to the thickness of the protection edge in the intermediate portions of the sides to the extent ranging from 2 to 10 times, preferably from 3 to 5 times, with respect to the thickness of the protection edge in the intermediate portions of the rectilinear sides.

The terminal portions inclined inwardly of the rectilinear sides of the edge of the base body have the function to deviate, at least for a partial component, the forces exerted on the corner region in case of fall in a direction parallel to the edge on the rectilinear sides, so that to limit the deformation impact due to the fact that said deformations forces generally have a predominant component in a direction perpendicular to the edge and therefore a greater damaging effect for the edge of the panel with respect to the components parallel to the edge.

Still according to a further characteristic, in the thicker regions of the protection edge at the recesses of the corner regions in the base body or in the optional recesses at intermediate points of the rectilinear sides, one or more through holes essentially oriented in a transverse manner, in particular perpendicularly to the panel faces, are provided in the protection edge.

Said holes can also be non-through holes and interrupted by a least one meniscus of reduced thickness with respect to the overall depth of the hole and which meniscus can be provided in different axial positions of the hole.

These types of recessed segments or portions of the peripheral edge of the base body can also be present in one or more intermediate regions between the corner regions of the panel and/or base body and also in this case the protection edge extends to an extent so that to fill said recessed regions, maintaining the external surface thereof at said recessed zone(s) flush with the external surface of the adjacent portions or so that to connect with the external surface of said adjacent portions of the protection edge in a continuous manner, that is without interruptions.

Still according to an embodiment, the thickness of the protection edge in the direction perpendicular to the surfaces of the panel is larger with respect to the thickness of the base body, the surfaces of the protection edge parallel to the surfaces of the faces of the base body connecting to these surfaces of the faces of the base body by means of inclined and/or flared portions so that to avoid steps or interruptions at the connecting regions.

Preferably, the thickness increase of the protection edge in the direction perpendicular to the panel faces is provided in the order of magnitude from 0.5 to 10% of the thickness of the base body.

The surfaces parallel to the faces of the base body extend along a more external peripheral strip of the thickness of the protection edge in a direction parallel to the faces of the panel and have a smaller extension with respect to the inclined surfaces of the protection edge connecting to the surfaces of the faces of the base body, preferably for example ranging from 10% to 50% of the extension of the surfaces inclined in a direction perpendicular to the surfaces of the edge of the base body and parallel to the faces of the base body.

According to an embodiment, each panel is composed of a base body consisting of a plate-shaped piece with at least one core layer made of natural or synthetic single or multilayer material or a combination of said natural and synthetic materials. The base body has length, width and thickness so that to resist to the stress of the concrete without deforming and contemporaneously, however, so that to have a certain handiness with regard to the personnel assigned to the transport and mounting of the formwork and has smaller predetermined width, length and/or thickness with respect to the final size of the panel also comprising the protection edge in combination.

According to an embodiment, a coating layer made of waterproof material can be provided on one or both of the faces of the core layer. The coating layer can be single or multilayer and can be composed of one or more layers of protecting paint, one or more layers of a resin and combination of resins, one or more films or one or more layers or one or more plates of plastic material or the like, or a combination of any of these layers.

Object of the invention is also a method for manufacturing the aforesaid panel, which provides the following steps:

arranging a sized base body having a predetermined plan shape and a predetermined section shape of the surface of the peripheral edge;

applying, by injection molding, a protection edge to the peripheral edge of the sized body.

Still according to a further characteristic, the process provides for the making of one or more through or non-through holes in predetermined areas and with orientation essentially perpendicular to the faces of the panel is provided, which holes are made contemporaneously with the injection molding step or in a following processing step by material removal.

Still according to a further characteristic, the invention provides for the step of making lightening cavities in the bulk of plastic material forming the protection edge is provided contemporaneously with the injection molding step.

Still according to a characteristic, the invention comprises a combination of at least one panel and one loadbearing structure for panels for making retaining walls for concrete casting, in particular for concrete slabs or the like, wherein the panel(s) are made according to one or more of any combinations of the embodiments and embodiment variations described above, while the panels are arranged directly adjacent one with respect to the other and with the external surfaces of the protection edges in contact with each other, so that to form an essentially continuous retaining wall, without marks in the contact regions between adjacent panels and substantially holding the concrete bulk.

According to an embodiment, the framework is of the type comprising a loadbearing structure composed of a plurality of supporting vertical posts of a combination of longitudinal beams and/or cross members parallel to one another and of supporting frames intended to rest with at least two opposite sides on two adjacent longitudinal members and/or cross members parallel to one another and on which frames a panel is respectively fastened in place, each frame being made with a shape essentially corresponding to the plan shape of a panel and the dimensions of the frames being smaller than the corresponding dimensions of the panels, while the panels are mounted on frames in positions so that to project on all sides and for a predetermined extent beyond the corresponding side of the panel, optionally in a symmetrical manner for sides of the panel opposite each other.

The invention has further characteristics which are object of the sub-claims. The characteristics of the invention and the advantages deriving therefrom will become clearer from the following description of a non- limiting exemplary embodiment shown in the accompanying drawings, in which:

Fig. 1 shows a plan view on a panel part according to a preferred embodiment of the present invention.

Figure 2 shows an enlarged particular of the cross section of the peripheral edge of the panel according to the present invention at an intermediate point of a rectilinear side.

Figure 3 shows a particular of a structure for the making of a formwork for making concrete slabs, which loadbearing structure is made for being used in combination with the panels of the present invention.

With reference to figures 1 and 2, a panel according to the present invention for making retaining walls of formworks for concrete casting, in particular for retaining formworks for making concrete slabs or the like, comprises a base body 1 which is composed of a sized piece with predetermined size and plan shape of an essentially flat plate. The base body has a single or multilayer structure and can be composed of one or more natural or synthetic materials or a combination of these materials, in particular according to one or more of the known configurations of these plates in the state of the art.

The base body 1 has a predetermined thickness d1 (fig. 2) and has a perimetric edge surface generally denoted by 101. A protection edge 2, which adheres with an internal surface 102 to the surface 101 of the edge of the base body 1 by shape coupling and by chemical/physical adhesion, is applied along the peripheral surface 101 of the base body. The protection edge 2 is made in one piece, that is the material of which it is composed does not substantially have an interruption and does not consist of different parts joined to one another at the time of application to the base body and/or also at a previous time.

The thickness S of the protection edge 2 is so that the essentially flat external surfaces of said protection edge 2 extend at a certain distance from the surfaces 101 of the edge of the base body 1 and complete the shape of the base body to the essentially rectangular shape of the finished panel.

In the embodiment shown, the base body 1 has corner regions shaped so that to be recessed with respect to the rectangular plan shape that would be obtained by extending the rectilinear sides of the edge of the base body 1 up to the mutual incidence point thereof. This way, in the corner region, the protection edge 2 has a larger thickness with respect to the S one present in the rectilinear portions.

As is clear, the thickness of the protection edge is about 3 to 4 times the thickness S at the intermediate points of the rectilinear panel portions along the bisector of the corner of the panel.

The increase in thickness in the corner regions is obtained to increase the ability of the protection edge to absorb the forces of impact in case of panel fall. The greater stress regions are the panel corner ones and therefore, in these regions, a larger thickness of the protection edge in a direction parallel to the panel faces ensures that the material of the protection edge can compensate the deformations caused by the forces of impact.

According to a further improvement, at the corner regions, the edge of the base body 1 is rounded with a predetermined radius of curvature, whereas the protection edge 2 forms a right angle vertex. As shown by the circle C in figure 1. This characteristic allows to generate a surface of progressive deviation of forces with the major component oriented in direction perpendicular to the surface of the edge of the base body 1 in forces in which part of the energy is deviated from said perpendicular component to a component parallel or tangent to the surface 101 of the base body in the arched corner region.

Still according to a further characteristic of improvement, the arched rounding portion of the corner regions of the surface of the edge of the base body 1 is recessed with respect to a position in which the circle C is tangent to the straight lines coinciding with the rectilinear sides of said surface 101 of the edge of the base body 1 and the two ends of the arched portion connect to the rectilinear sides of the surface of the edge of the base body 1 oriented perpendicularly to one another with an end portion inclined inwards with respect to the external surface of the protection edge 2 denoted by 201 in figure 1. The two end portions 201 of the rectilinear sides of the edges 101 of the base body 1 have a predetermined inclination in the order ranging from 2 to 20°, preferably between 5 and 10° with respect to the rectilinear portion of the corresponding side of the edge 101 of the base body 1.

Thanks to this characteristic, the components of the forces of impact oriented perpendicularly to the surface of the edge 101 of the base body 1 are further reduced and partially transferred on the components parallel to the corresponding rectilinear side in a progressive manner. Moreover, since they do not have sudden step- shaped recesses, a larger thickness of the protection edge 2 is maintained, however limiting the amount of material of said protection edge 2.

The embodiment shown is the preferred one, but can vary depending on the type of materials used both for the protection edge and base body 1.

With reference to a further characteristic shown in figure 2, the mutual contact surfaces 101 and 201 are shaped so that to have non- flat surface fronts of the edges of the base body 1 and of the protection edge 2.

Figure 2 shows a preferred embodiment, wherein the cross section of the surface of the edge 101 of the base body 1 is wedge-like shaped and preferably symmetrical to a median plan of the base body 1 which is parallel to the faces thereof.

The protection edge 2 has a contact surface 102 in contact with the surface of the edge 101 of the base body which is of an exactly corresponding shape so that to also generate a precise shape coupling between the base body 1 and the protection edge 2 and therefore has a wedge-like groove of exactly the same shape and size as the one projecting from the surface of the edge 101 of the base body 1.

According to a first variation of the embodiment shown, the wedge-like shape has a flattening at the vertex, i.e. at the tip of the wedge-like shape both at the part projecting from the surface of the edge 101 of the base body 1 and at the groove forming the corresponding contact surface on the protection edge 2.

Still according to a further characteristic, projections or projecting ribs 301 , which project from the surface 101 of the edge of the base body 1 and which engage by precise shape coupling in the corresponding recesses of the walls of the groove present in the protection edge 2 are provided along one or more of the mutual contact surfaces 101 , 102 between the protection edge and the peripheral edge of the base body 1. The ribs or teeth can vary both in number and shape and contribute to provide a mechanical gripping coupling of the protection edge 2 to the edge of the base body 1. These can be different per regions and size and number and/or shape and they can be continuous and/or discontinuous. Obviously, this is also valid for the corresponding recesses of the contact surface of the protection edge 2.

The thickness difference in the direction perpendicular to the edge of the base body 1 and parallel to the faces thereof, between the region of smaller thickness S1 of the protection edge 2 and the peripheral one of larger thickness S at the faces of the base body 1 , can be so that the region of larger thickness S is from 1.5 to 10 times the thickness of the region of smaller thickness S1 , preferably from 3 to 5 times said thickness S1.

It should be noted that this characteristic also contributes to improve the protection of the corners of the edge at the two opposite faces of the panel, since the inclined surfaces of the wedge-like shape of the edge 101 of the base body eliminate the highly deformable regions, such as the corners, and partially deviate the perpendicular components in shear components with respect to the edge, that is in components perpendicular to the panel faces.

As shown in figure 2, the panel according to the present invention can also comprise, in any combination with the characteristics previously described, the characteristic according to which the thickness of the protection edge 2 is larger than the thickness of the base body 1 in a direction perpendicular to the faces thereof, at least for part of the extension of the protection edge 2 both in the longitudinal direction thereof and in a direction perpendicular to the edge 101 of the base body 1. The larger thickness is symmetrically distributed with respect to the central median plane of the base body which is parallel to the faces thereof and determines that the protection edge 2 projects for at least part of its extension to the extent d2 from both the faces of the base body 1. As is clear, the projecting surfaces of the protection edge 2 with respect to the faces of the base body 1 extend along a more external peripheral strip of the protection edge 2 and for a thickness S1 in a direction perpendicular to the edge and parallel to the faces of the base body 1 which is a whole submultiple of the maximum thickness S of the protection edge 2. The portion comprised between the most internal limit of the projecting strip to the extent d2 of the protection edge 2 and the edge of the base body 1 is inclined and is denoted by 402, while the external strip along which the protection edge 2 projects to the extent d2 beyond the corresponding strip of the base body 1 is denoted by 502.

Still according to a further characteristic, the thickness S1 of the strips 502 is substantially corresponding to the thickness S1 of the protection edge 2 at the bottom of the groove coupling with the wedge- like shape of the edge 101 of the base body 1.

Still according to an advantageous characteristic, 6 denotes the cavities produced in the larger thickness region of the protection edge 2. These cavities can advantageously be obtained by means of known gas injection technologies such as will be described more in detail below.

Thanks to these cavities, the weight is lightened, the protection edge is made more elastically flexible and the costs of materials are reduced.

The cavities can be continuous or discontinuous and different from one another in different regions of the protection edge 2, both in shape and size. Object of the invention is a process for manufacturing panels according to one or more of the preceding claims, which provides for the arranging of a base body from a plate and which arrangement provides for the possible coating of the faces of a core plate with one or more coating layers, and cut-to-size and molding processing according to one or more of the previous claims.

Moreover, in a subsequent step, the process provides the application of the protection edge to the base body prepared according to the steps described above in an injection molding process of the material of the protection edge on the peripheral edge of the base body.

The material is preferably a plastic polyurethane material or a mixture of plastic materials. These materials are selected depending on the characteristics of the use conditions and on the mechanical characteristics of resistance and elasticity defined by the expected use.

During the injection molding step of the protection edge 2, it is possible to provide steps for making the cavities 6 and also steps for contemporaneously making the holes 4 for the nails.

Still according to a further characteristic, the invention provides a structure for the making of a retaining wall of formworks for concrete castings, in particular for retaining formworks for making concrete slabs or the like, which comprises a supporting framework denoted by 30 in figure 3 and which comprises posts 31 of which only the terminal end is shown and which support a combination of longitudinal members and cross members. In figure 3, the structure provides longitudinal members 32 which rest on a plurality of posts 31 , while the cross members are part of an essentially rectangular framework 33 comprising head sides 133 parallel to the longitudinal members 32 and which are intended to rest on said longitudinal members by engaging with a resting foot in an engagement seat 132.

As is clear, each longitudinal member cooperates with a couple of frames 33 arranged side by side, each of which with its head side 133 on the longitudinal member 32. Each frame 33 bears a panel 34 according to one or more of the variations described with reference to the preceding figures, fixed on the upper side. The panels are arranged side by side to one another and adhere flush one with respect to the other and in a sealed way with respect to the concrete casting along the facing edges in direct contact with the protection edges. To this end, the frames 33 are made of smaller sizes with respect to the external sizes of the panels 34, both in the longitudinal direction and in the transverse direction and are mounted on the corresponding frame essentially in a centered position with respect to the same, so that to project of a predetermined extent on all four sides and to a substantially identical extent from the frame 33, at least on two sides opposite one another. Therefore, in a mounted condition, the panels 34 form a continuous retaining plane by adhering directly one to another and, thanks to this, reducing the traces or prints of the joints between a panel and another, which are instead present in the currently known formworks. It is clear that the structure comprising the frame and panel combination can also be very different as configuration of the single parts, the only essential characteristic being the dimensional ratio between the panel and supporting frame thereof and the panel and clearances between the supporting beams of the panel when for example a frame 33 is not provided, but the panel is mounted directly on a framework.