Sheet metal covering system for roofs and the like

Abstract

 A sheet metal covering system for roofs and the like, comprising a plurality of supporting and retention brackets (1) that are supported by a load-bearing structure (50), and a plurality of metal sheets (20), each metal sheet (20) having two opposite edges (18a, 18b) that are folded complementarily and are adapted to allow the coupling of two adjacent metal sheets (20) by partial overlap of the edges (18a, 18b) over one of the supporting brackets (1), each supporting bracket (1) having a longitudinal extension that is adapted to provide a contact surface for the edges (18a, 18b) of the metal sheets and a transverse cross-section that is substantially symmetric with respect to a vertical axis, the head (4) of the bracket (1) having a symmetric transverse profile that is substantially rounded, at least in its lateral cross-sections, and comprising curved lateral surfaces (15a, 15b) that are extended in a longitudinal direction and are adapted to make contact with surfaces (27a, 27b, 29) that are complementary to them and are formed on the edges (18a, 18b) of adjacent metal sheets.

Description

[0001] The present invention relates to a sheet metal covering system for roofs and the like.

[0002] Several sheet metal covering systems for roofs have already been provided at present; though achieving the aim of ensuring good covering of roofs of buildings both for civil and industrial use, they suffer drawbacks mostly related to resistance to external environmental stresses.

[0003] These conventional solutions are not free from drawbacks.

[0004] Evolution of materials in fact allows to use ever thinner metal sheets, whereas design requirements need ever longer monolithic sheet metal elements. These factors, together with the changes in the weather conditions in recent years, with tropical rainfall with winds that are unusual for our latitudes, have caused the resistance to pressure and negative pressure of the covering systems currently in use to be no longer sufficient to ensure the necessary resistance. In particular, the systems currently in use have a limited resistance to loads that tend to extract the metal sheets from their supports and are due for example, as mentioned, to the negative pressure or suction produced by wind.

[0005] Among the systems currently in use, reference is made to the subject of patent EP 0530483 A1, which has a supporting bracket characterized by an asymmetric profile that has a hook-like shape and limited extension of the two metal sheets at the complementary edges.

[0006] This solution provides a bracket with a structure that is not very adapted to withstand external stresses that induce its flexing.

[0007] Patent GB 2279379 A relates to a system for supporting and fixing the metal sheets in which a plurality of pairs of substantially vertically elongated laminar elements arranged on a transverse plane act as anchoring for the folded metal sheets. In this case, the surfaces for contact between the metal sheet and the supports are limited, while the fixing laminar elements have a very limited longitudinal extension.

[0008] Finally, patent EP 0634535 B1 discloses a supporting bracket that is characterized by splayed portions, sharp edges and longitudinal elongation, having a symmetric transverse cross-section and adapted to be fixed to the supporting structure directly by means of retaining bolts that enter through holes. The portion of folded metal sheet is coupled by means of a fold or bend formed by two S-shaped consecutive folds, which fits within a corresponding recess or cradle formed in the bracket. In this case also, the surface for contact and retention of the folded metal sheet on the bracket is limited to the surface generated by the longitudinal extension of said portion characterized by two consecutive folds, and is subjected to potentially destructive stress concentrations.

[0009] The aim of the present invention is to eliminate or substantially reduce the mentioned drawbacks observed in the solutions currently in use.

[0010] Within this aim, an object of the invention is to provide a flat covering system made of folded sheet metal for roofs that is capable of withstanding very high disengagement loads, approximately twice as high as the loads that the solutions currently in use can withstand, ensuring at the same time an excellent distribution of stresses due to atmospheric factors on the surface of the bracket.

[0011] Another object of the invention is to provide a covering system in which the metal sheets are anchored without producing through holes in said metal sheets and which ensures good draining of rainwater or water produced by the melting of snow or ice.

[0012] Another object of the invention is to provide a covering system that is reliable and at the same time low in cost, both in terms of the materials used and in terms of their manufacture and installation.

[0013] In particular, in advantageous embodiments the invention proposes, in order to deal with the negative pressure produced by wind and atmospheric agents in general, which tends to disengage the metal sheets from the supports, cross-sections of the heads and of the joint ribs that are studied specifically and are larger than usual, with a consequent change in the dimensions of the anchoring brackets, in order to have a large contact surface between the edges of the folded metal sheet and the supporting brackets.

[0014] Furthermore, transverse stiffening elements have been introduced in the flat part of the metal sheets and are adapted to reduce their deformability. This detail allows, in combination with the effect produced by the particular shape of the brackets, to eliminate the typical undulation of all thin rolled metal sheets.

[0015] Further features, advantages and objects that will become better apparent hereinafter, are achieved by a sheet metal covering system for roofs and the like, comprising a plurality of supporting and retention brackets that are supported by a load-bearing structure, and a plurality of metal sheets, each one of said metal sheets having two opposite edges that are folded complementarily and are adapted to allow the coupling of two adjacent metal sheets by partial overlap of said edges over one of said supporting brackets, each one of said supporting brackets having a longitudinal extension that is adapted to provide a contact surface for said edges of said metal sheets and a transverse cross-section that is substantially symmetric with respect to a vertical axis, and being constituted by a footing that is adapted for fixing to said load-bearing structure and by a head that is connected thereto and is contoured so as to have, along its longitudinal extension, several grooves that are adapted to interfere with corresponding folds formed on said edges of said adjacent metal sheets, characterized in that said head of said bracket has a symmetric transverse profile that is substantially rounded, at least in its lateral cross-sections, comprising curved lateral surfaces that are extended in a longitudinal direction and are adapted to make contact with surfaces that are complementary to them and are formed on said edges of said adjacent metal sheets.

[0016] Advantageously, said head of said bracket is connected to said footing by a connecting stem that is substantially perpendicular thereto and has a smaller transverse dimension than said head and said footing and has, in its longitudinal extension, flat vertical lateral surfaces that are adapted to make contact with corresponding vertical portions of said folded edges of said metal sheets.

[0017] Advantageously, moreover, the head of said bracket has said substantially rounded symmetric transverse profile constituted by a laminar or diaphragm-like portion that is substantially perpendicular to said connecting stem and ends, at each of its two ends, with a wing that protrudes in a substantially vertical direction above and below said laminar or diaphragm-like portion and is folded so that the concavity lies toward the axis of symmetry of said bracket and is lobe-shaped.

[0018] In a preferred embodiment, the supporting and retention bracket of the system according to the invention has a substantially T-shaped structure that is constituted by a footing, by a connecting stem that is substantially perpendicular to the footing, and by a head that is arranged substantially horizontally and parallel to said footing and has recesses in which complementary folds formed on the folded edges of two adjacent metal sheets are inserted.

[0019] The supporting and retention bracket according to the invention introduces the following shape concept: the head of the bracket has a profile with curved lateral surfaces that are adapted to mate with the complementary curved surfaces of the edges of the metal sheets. This configuration with rounded surfaces is one that optimizes contact between the two surfaces and increases the stability of the assembled system.

[0020] Moreover, in the head of the bracket there are various grooves of different types that are designed to provide recesses, edges and comers that are adapted to provide an engagement for the folded edges of the metal sheets and to improve the retention of the metal sheets on the head of the bracket, while avoiding formation of stress concentration points or regions.

[0021] Among these grooves, a recess formed on the upper part of the head of the bracket allows to block the rise of water by capillary action and compensates for gutter drainage if the joint is completely submerged by water.

[0022] Recesses formed at the sides of the head of the bracket allow additional engagement of the metal sheet element with the bracket.

[0023] Lower recesses allow, during the coupling of the element to the bracket, a small but very rigid engagement that allows to achieve the sought good resistance to external loads.

[0024] Further characteristics and advantages of the invention will become better apparent from the description of a preferred but not exclusive embodiment of the system according to the invention, illustrated by way of non-limiting example with reference to the accompanying drawings, wherein:

Figure 1 is a perspective exploded view showing the system according to the invention;

Figure 2 is a perspective view showing the supporting bracket according to the invention;

Figure 3 is an exploded front view showing the system according to the invention, illustrating with greater clarity the profile of the bracket and the profiles of two adjacent sheet metal elements;

Figure 4 is a front view showing the system according to the invention in the assembled condition, again illustrating the bracket and the two adjacent sheet metal elements in the assembled condition, so as to provide partial covering, and during the initial step of their coupling;

Figure 5 is a perspective view showing the system according to the invention, assembled as in Figure 4;

Figure 6 is a front view showing the system according to the invention in the assembled condition, illustrating the bracket and the two sheet metal elements provided according to a different embodiment, with a flat step in the lower part of the edge;

Figure 7 is a perspective view of the supporting bracket according to the invention in the inverted position.

[0025] With reference to the figures, the sheet metal covering system for roofs according to the invention comprises a plurality of metal plates or sheets in which the two non-adjacent and opposite edges of each metal sheet are folded complementarily, so as to allow the coupling of two adjacent metal sheets by partial overlap or elastic interlocking.

[0026] At the overlap or interlocking region there is a bracket 1 for supporting and retaining the metal sheets on the load-bearing structure of the roof 50 of the building. Said brackets can be aligned and spaced along and below the portions that join the two adjacent metal sheets.

[0027] More particularly, with reference to Figures 1 and 3, each metal sheet comprises a flat central body or portion 20, which in the reference drawings forms a horizontal plane that is optionally crossed by longitudinal reinforcement ribs 38 and by transverse ridges 39 and is provided, at each one of the folded edges 18a and 18b, with a raised portion constituted by the portion of metal sheet, designated by the reference numerals 21a and 21 b respectively, that is inclined with respect to the horizontal direction, and by the flat portion 22a and 22b, respectively, that ends with a second inclined portion 23a and 23b.

[0028] With reference to Figure 3, and merely by way of example, the metal sheet with the edge 18a is arranged to the left of the bracket, and the metal sheet with the edge 18b is arranged to the right of the bracket.

[0029] A substantially vertical portion, designated by the reference numerals 24a and 24b respectively, extends from each one of the two inclined portions 23a and 23b.

[0030] With reference to Figure 3, the two complementarily folded edges 18a and 18b comprise the following elements that are common to both edges :

a first connecting portion 25a and 25b respectively, which interrupts the extension of the vertical portion 24a and 24b respectively, bending the sheet metal downwardly to a subsequent connecting portion 26a and 26b, which again bends the sheet metal upwardly, accordingly forming an S-shaped configuration and forming, toward the inside of the profile, a recess, designated by the reference numerals 28a and 28b respectively, that is produced by the curvature of the portions 26a and 26b, and a hollow formed by the connecting portion 25a and 25b respectively.

"Downwardly" and "upwardly" are terms that are used herein only for the purpose of the description and are not intended to be limitative. They refer to the structure of the various parts of the covering systems when arranged with the bracket vertical and the sheets lying horizontal. In use, as the skilled person would understand, the sheet and bracket system may also be arranged on inclined or sloped roofs.

[0031] As an alternative to the described configuration and with reference to Figure 6, the two edges 18a and 18b can be constituted, at the end of the vertical portions 24a and 24b, by connecting portions 40a and 40b that interrupt the vertical extension of the portions 24a and 24b respectively, by folding the sheet metal until each one constitutes a flat portion 41 a and 41 b, each one of said portions 41a and 41b being substantially parallel to the horizontal direction traced by the portions 20a and 20b, said portions 40a and 40b being interrupted respectively by the portions 26a and 26b, which again fold the sheet metal upwardly, accordingly forming a flat step that is constituted by the portions 41a and 41b respectively.

[0032] In the first embodiment and in the second embodiment, the metal sheet further has, at both edges 18a and 18b, a portion with constant curvature, designated by the reference numerals 27a and 27b respectively, in which the concavity is directed toward the side of the bracket. The profile 27b is interrupted at its central portion by an indent or convex portion 5c.

[0033] The curved portion 27a of the edge 18a ends with a substantially horizontal portion 19, which is then curved again downwardly, forming the curved portion 29, which ends with a short portion 30 that is bent with respect to the vertical toward the inside of the curved portion 29 so as to form a substantially horizontal portion.

[0034] The curved portion 27b of the edge 18b again curves downwardly with a connecting portion 31 that forms a concavity 32 and has, after an oblique portion 33, a second connecting portion 34, which ends with a substantially horizontal portion 35, which ends with a further element 36 that curves upwardly and an oblique element 37 that is substantially parallel to the portion 33.

[0035] The curved portion 29 has a larger radius of curvature than the portion 27b, so that it can overlap said portion 27b, as shown in Figure 4, which illustrates the system in its final assembled configuration.

[0036] With reference to Figures 2 and 3, the bracket of the system according to the invention has a substantially cross-sectionally T-shaped structure with a longitudinal width suitable for extensive support for the sheet edges, that is constituted by a footing 2, a connecting stem 3 that is perpendicular to the footing 2, and a head 4 that is elongated substantially horizontally and parallel to said footing and has at least two engagement elements 12 (12a, 12b) for complementary folds provided on the folded edges of the two adjacent metal sheets.

[0037] The head 4 of the bracket has a cross-sectional profile with curved surfaces that are adapted to mate with the complementary curved surfaces of the edges of the metal sheets. This configuration with rounded surfaces is the one that optimizes contact between the two surfaces and increases the stability of the assembled system.

[0038] Recesses or grooves 5a and 5b formed at the sides of the head of the bracket allow additional engagement of the edges of the metal sheets with the bracket.

[0039] The footing 2 is a structural element of the bracket, since fixing holes 7, 8 and 9 of various kinds and dimensions are provided at solid regions thereon in order to adapt to the different types of element for fixing on the supporting structure of the roof.

[0040] Stiffening ribs 51, shown in Figure 7, connect on the solid regions with said fixing holes 7, 8 and 9 therein and are provided on the lower part of the footing 2 in order to make the base lightweight but rigid.

[0041] The head of the bracket has, as shown in Figure 3, a substantially bisymmetric profile, i.e., symmetric with respect to a first substantially vertical axis that coincides, in the embodiment of this example, with the axis of the connecting stem 3, and symmetric with respect to a second axis that is substantially perpendicular to the first axis and coincides, in the embodiment of this example, with the axis of a laminar or diaphragm-like portion 11 that is substantially horizontal. The laminar or diaphragm-like portion 11 surmounts the connecting stem 3. At each one of the two ends of said laminar or diaphragm-like portion 11 there is a wing with a curved profile, designated by the reference numerals 15a and 15b respectively, in which the concavity is directed toward the axis of symmetry and is lobe-shaped, having substantially the overall configuration of the Greek letter "ε".

[0042] Each one of said wings 15a and 15b encloses in a downward region a respective recess and has, in the central region substantially at said laminar or diaphragm-like portion 11, splayed portions, designated by the reference numerals 5a and 5b respectively, that form grooves which divide each one of said wings into two substantially identical portions: portions, designated respectively by the reference numerals 4a and 4b, that lie above said laminar or diaphragm-like portion 11 and end with edges, designated respectively by the reference numerals 10a and 10b and enclose an upper recess 15e; and portions 6a and 6b, which lie below them and end with edges designated respectively by the reference numerals 12a and 12b, that enclose recesses 15c, 15d.

[0043] Said portions 4a and 4b and 6a and 6b have the same curvature as the portions 27a and 27b, so that said portions 4a and 4b and 6a and 6b are substantially parallel to said portions 27a and 27b, and their length is such that the portion 27a can overlap the profile 15a and the portion 27b can overlap the profile 15b.

[0044] The details described above contribute to the uniform distribution of the stresses caused by particularly severe atmospheric conditions and effectively avoid concentrations of stresses in the folded edges of the metal sheets or on the brackets.

[0045] The bracket according to the invention can be made of plastics, aluminum and alloys thereof or brass, and is obtained by extrusion, in the case of plastic materials, aluminum and alloys thereof and brass, and also by pressure die-casting, in the case of aluminum and alloys thereof, and by molding in the case of plastic materials.

[0046] The system is assembled as follows.

[0047] The flat portions 20a and 20b rest directly on the roof 50 of the building; the inclined portions 21a and 21 b act as connecting elements for blending with the horizontal portions 22a and 22b that rest on the horizontal surfaces 14 of the base or footing 2 of the bracket 1.

[0048] The inclined portions 23a and 23b in turn rest on the inclined surfaces 13 of the base of the bracket and the substantially perpendicular portions 24a and 24b rest on the two opposite faces 3a and 3b of the substantially vertical connecting stem 3 of the bracket.

[0049] The portion 27b, as shown in Figure 4, overlaps the portions 4b and 6b of the bracket, so that the edge 12b enters the recess 28b, the edge 10b enters the recess 32 and the convex portion indent or fold 5c enters the splayed portion groove 5b.

[0050] The surface formed by the profile 37 rests on the edge 10a, and the two horizontal portions, the metal sheet portion 35 and the head portion of the bracket 1, form a cavity 60.

[0051] Likewise, the surface formed by the portion 27a overlaps the surfaces formed by the portions 4a and 6a, and the edge 12a enters the recess 28a.

[0052] With reference to Figure 4, the horizontal portion 19 forms, together with the portion 35 of the adjacent metal sheet, a recess 61, while the curved portion 29 is, in the assembly step, in the configuration indicated by the profile shown in dashed lines 60, i.e., the profile is open. The curved portion 29 has a larger radius of curvature than the portion 27b and is superimposed and made to adhere thereto by means of a seaming operation, by means of which appropriately shaped rollers or jaws or suitable means of manual or automated seaming machines, shown only schematically in the figure by means of the dashed-line profiles 61a, 61b and 61c, produce the deformation of the portion of sheet metal until the system is stably engaged. In this manner, the portion 29 is superimposed on the portion 27b, to which it is coupled also by the presence of the surface formed by the longitudinal extension of a retaining profile 30.

[0053] According to what has been described above, it is possible to define a method for assembling and fixing the sheet metal covering system for roofs and the like, characterized in that it comprises the steps of providing a plurality of metal sheets according to the invention, i.e., metal sheets in which each one has two opposite edges that are folded complementarily and are adapted to allow the coupling of two adjacent metal sheets by partial overlap of said edges over a supporting and retention bracket, and of providing a plurality of supporting and retention brackets, each of which has a longitudinal extension that is adapted to provide a contact surface for the edges of said metal sheets and has a transverse cross-section that is substantially symmetric with respect to a vertical axis, and being constituted by a footing that is adapted for fixing to a supporting structure and by a head that is connected thereto and is shaped so as to have a bisymmetric transverse profile that is substantially rounded and comprises curved lateral surfaces that are elongated in a longitudinal direction and are adapted to make contact with surfaces that are complementary thereto and are formed on said edges of said adjacent metal sheets and comprise, in their longitudinal extension, several grooves that are adapted to interfere with corresponding folds formed on said edges of said adjacent metal sheets. The method as described above further fixes said supporting and retention brackets through the corresponding footings to a supporting structure and fixes said metal sheets so that an edge of a metal sheet is stably connected to the head of said supporting bracket and an edge that is complementary thereto of an adjacent metal sheet overlaps the first edge and is also fixed to the head of the supporting element by way of the folds that are complementary to the recesses of the head and completely surrounds the head of said bracket, this last operation being facilitated by the seaming operation as described earlier.

[0054] From what has been described above it is therefore evident that the invention achieves the intended aim and objects and in particular achieves the aim of withstanding far higher stresses than currently known systems.

[0055] Laboratory tests performed at the Istituto per le Tecnologie della Costruzione ITC (Building Technologies Institute) of the Consiglio Nazionale Delle Ricerche (National Research Council) show that the resistance to negative pressure (see water tightness - upward load resistance test), is more than 300 kg/mq, i.e., more than twice the value normally found in these structures.

[0056] The supporting and retention bracket according to the invention has a footing with a contact surface that is approximately three times as wide as said head and a connecting stem that is substantially perpendicular to said footing and is approximately as high as said footing is wide. Said footing is a characterizing element of the bracket, since fixing holes of various kinds and sizes are provided thereon in order to adapt to the different types of coupling to the load-bearing structure that supports the roof.

[0057] Stiffening bridges that converge on said holes are provided in the lower part of said base in order to make the base lightweight but rigid.

[0058] This configuration of the base allows to fix the bracket to the load-bearing supporting structure by means of templates and by means of direct fixing on the rib of the element, achieving in this last case the additional advantage of speeding up installation times.

[0059] The stem for connecting the footing to the head is sized so as to not undergo deformations caused by the action of the external loads.

[0060] The present invention is susceptible of modifications and variations, all of which are within the scope of the appended claims.

[0061] All the details may further be replaced with other technically equivalent elements; the materials and the dimensions and the contingent shapes may be changed according to requirements.

[0062] The disclosures in Italian Patent Application No. MI2003A001246 from which this application claims priority are incorporated herein by reference.

[0063] Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims

1. A sheet metal covering system for roofs and the like, comprising a plurality of supporting and retention brackets (1) that are supported by a load-bearing structure (50), and a plurality of metal sheets (20), each one of said metal sheets having two opposite edges (18a, 18b) that are folded complementarily and are adapted to allow the coupling of two adjacent metal sheets by partial overlap of said edges (18a, 18b) over one of said supporting brackets (1), each one of said supporting brackets (1) having a longitudinal extension that is adapted to provide a contact surface for said edges (18a, 18b) of said metal sheets (20) and a transverse cross-section that is substantially symmetric with respect to a vertical axis, and being constituted by a footing (2) that is adapted for fixing to said load-bearing structure (50) and by a head (4) that is connected thereto and is contoured so as to have, along its longitudinal extension, several grooves (5, 5a, 5b) that are adapted to interfere with corresponding folds (5c) formed on said edges (18a, 18b) of said adjacent metal sheets (20), characterized in that said head (4) of each said bracket (1) has a symmetric transverse profile that is substantially rounded, at least in its lateral cross-sections, comprising curved lateral surfaces (15a, 15b) that are extended in a longitudinal direction and are adapted to make contact with surfaces (27a, 27b, 29) that are complementary to them and are formed on said edges (18a, 18b) of said adjacent metal sheets.

2. The sheet metal covering system for roofs and the like according to claim 1, characterized in that said head (4) of said bracket (1) is connected to said footing (2) by a connecting stem (3) that is substantially perpendicular thereto and whose transverse dimension is smaller than said head (4) and said footing (2) and has, in its longitudinal extension, flat vertical lateral surfaces (3a, 3b) that are adapted to make contact with corresponding vertical portions (24a, 24b) of said folded edges (18a, 18b) of said metal sheets (20).

3. The sheet metal covering system for roofs and the like according to one or more of the preceding claims, characterized in that said substantially rounded symmetric transverse profile of said head (4) of said bracket (1) is constituted by a laminar or diaphragm-like portion (11) that is substantially perpendicular to said connecting stem (3) and ends at each of its two ends with a wing (15a, 15b) that protrudes in a substantially vertical direction above and below said laminar or diaphragm-like portion and is folded, to form said curved lateral surfaces, so that the concavity is directed toward the axis of symmetry of said bracket (1) and is lobe-shaped.

4. The sheet metal covering system for roofs and the like according to one or more of the preceding claims, characterized in that said head (4) of said bracket (1) has a substantially bisymmetric transverse profile, being symmetric with respect to a first substantially vertical axis and with respect to a second axis that is substantially perpendicular to the first axis.

5. The sheet metal covering system for roofs and the like according to one or more of the preceding claims, characterized in that said curved wings (15a, 15b) form, in a downward region, two recesses (15c, 15d) that are separated by said vertical connecting stem (3) and, in an upward region, an upper recess (15e) that is limited in a downward region by said laminar or diaphragm-like portion (11) and laterally by said wings (15a, 15b).

6. The sheet metal covering system for roofs and the like according to one or more of the preceding claims, characterized in that each one of said wings (15a, 15b) has a transverse profile that is symmetric with respect to said laminar or diaphragm-like portion (11) and has at least one groove (5a, 5b) in a central region of said curved lateral surface that has longitudinal extension.

7. The sheet metal covering system for roofs and the like according to one or more of the preceding claims, characterized in that said footing (2), said stem (3) and said head (4) of said bracket (1) have dimensions and proportions that are selected according to the material of which said bracket (1) is made and so that said covering system is capable of withstanding the application of an external load for disengaging said metal sheets (20) from said bracket (1) of at least 300 kg/mq.

8. The sheet metal covering system for roofs and the like according to one or more of the preceding claims, characterized in that said footing (2) of said bracket (1) has a box-like structure crossed by holes (7,8,9) that are formed in solid regions for fixing to said supporting structure (50) and comprises stiffening ribs (51) that join said solid regions of said fixing holes (7,8,9).

9. The sheet metal covering system for roofs and the like according to one or more of the preceding claims, characterized in that it comprises said opposite edges (18a, 18b) of said metal sheet (20), which are folded so that each one has at least one curved portion (27a, 27b, 29) that is complementary to the curvature of said lateral surfaces of the head (4) of said bracket (1), one (18a) of said opposite edges having a portion (29, 30) with a radius of curvature that is adapted to cover part of an edge (18b) that is complementary thereto of an adjacent metal sheet (20) and ends with a substantially horizontal retention profile (30), which extends so as to wrap around the head (4) of said bracket (1).

10. The sheet metal covering system for roofs and the like according to one or more of the preceding claims, characterized in that said opposite edges (18a, 18b) of said metal sheets (20) have folds with convex portions (5c) that are adapted to enter even partially said recesses (5a, 5b) formed by the wings (15a, 15b) of said head (4) of said bracket (1).

11. The sheet metal covering system for roofs and the like according to one or more of the preceding claims, characterized in that each one of said vertical portions (24a, 24b) of said folded edges (18a, 18b) of said metal sheets (20) ends with a substantially horizontal connecting portion (40a, 40b, 41 a, 41b).

12. The sheet metal covering system for roofs and the like according to one or more of the preceding claims, characterized in that each one of said vertical portions (24a, 24b) of said folded edges (18a, 18b) of said metal sheets (20) ends upwardly with a connecting portion (40a, 40b) that comprises a first portion (25a, 25b) that is folded downwardly and a second portion (26a, 26b) that is complementarily folded upwardly so as to form an S-shaped profile, and in that each one of said vertical portions (24a, 24b) ends downwardly, with inclined portions ( 23a, 23b, 21a, 21b) connected to flat portions (22a, 22b) that rest directly on the load-bearing structure (50).

13. The sheet metal covering system for roofs and the like according to one or more of the preceding claims, characterized in that said bracket (1) is made of plastic material.

14. The sheet metal covering system for roofs and the like according to one or more of the preceding claims, characterized in that said bracket (1) is made of a metallic material with physical characteristics that are suitable for roofing applications.

15. The sheet metal covering system for roofs and the like according to claim 13, characterized in that said bracket is made of reinforced polyamide.

16. The sheet metal covering system for roofs and the like according to claim 14, characterized in that said bracket (1) is made of aluminum or brass.

17. The sheet metal covering system for roofs and the like according to one or more of claims 13 to 16, characterized in that said bracket (1) is a molded piece.

18. The sheet metal covering system for roofs and the like according to one or more of claims 13 to 16, characterized in that said bracket (1) is an extension or extrusion made piece that is shaped by work on cutting machine tools.

19. The supporting and retention bracket (1) for metal sheets for covering roofs and the like, having a longitudinal extension that is adapted to provide a contact surface for the edges (18a, 18b) of said metal sheets and a transverse cross-section that is substantially symmetric with respect to a vertical axis, and being constituted by a footing (2) that is suitable for fixing to a load-bearing structure (50) and by a head (4) that is connected thereto and contoured so as to have, in its longitudinal extension, several grooves (5a, 5b) that are adapted to interfere with corresponding folds (5c) formed on said edges (18a, 18b) of said adjacent metal sheets (20), characterized in that said head (4) of said supporting bracket (1) has a substantially rounded symmetric transverse profile at least in its lateral cross-sections, comprising curved lateral surfaces (15a, 15b) that are extended longitudinally and are adapted to make contact with surfaces (27a, 27b, 29) that are complementary thereto and are formed on said edges (18a, 18b) of said adjacent metal sheets (20).

20. The supporting and retention bracket for metal sheets for covering roofs and the like according to claim 15, characterized in that said head (4) of the bracket (1) is connected to said footing (2) by a connecting stem (3) that is substantially perpendicular to said footing (2) and has a smaller transverse dimension than said head (4) and said footing (2) and has, in its longitudinal extension, flat vertical lateral surfaces (3a, 3b) that are adapted to make contact with corresponding folded vertical portions (24a, 24b) of said edges (18a, 18b) of said metal sheets (20).

21. The supporting and retention bracket for metal sheets for covering roofs and the like according to one or more of the preceding claims, characterized in that said substantially rounded symmetric transverse profile of said head (4) of the bracket is constituted by a laminar or diaphragm-like portion (11) that is substantially perpendicular to said connecting stem (3) and ends at each of its two ends with a wing (15a, 15b) that protrudes substantially vertically both above and below said laminar or diaphragm-like portion (11) and is folded so that its concavity is directed toward the axis of symmetry of the bracket (1) and is lobe-shaped.

22. The supporting and retention bracket according to one or more of the preceding claims, characterized in that said head (4) of the bracket (1) has a substantially bisymmetric transverse profile, being symmetric with respect to a first substantially vertical axis and with respect to a second axis that is substantially perpendicular to the first axis.

23. The supporting and retention bracket for metal sheets for covering roofs and the like according to one or more of the preceding claims, characterized in that said curved wings (15a, 15b) form in a downward region two recesses (15c, 15d) that are separated by said vertical connecting stem (3) and in an upward region a recess (15c) that is delimited in a downward region by said laminar or diaphragm-like portion (11) and is laterally delimited by said wings (15a, 15b).

24. The supporting and retention bracket for metal sheets for covering roofs and the like according to one or more of the preceding claims, characterized in that each one of said wings (15a, 15b) has a transverse profile that is symmetric with respect to said laminar or diaphragm-like portion (11) and has at least one groove (5a, 5b) in a central region of said longitudinally extended curved lateral surface.

25. The supporting and retention bracket for metal sheets for covering roofs and the like according to one or more of the preceding claims, characterized in that said footing (2) of the bracket has a box-like structure that is crossed by holes (7,8,9) formed in solid regions for fixing to said load-bearing structure (50) and comprises ribs (51) that join said solid regions of said fixing holes (7,8,9).

26. The supporting and retention bracket for metal sheets for covering roofs and the like according to one or more of the preceding claims, characterized in that said footing (2), said stem (3) and said head (4) of the bracket (1) have dimensions and proportions that are selected according to the material of which the bracket is made and so that the covering system is capable of withstanding the application of an external load for the disengagement of the metal sheets (20) from the brackets (1) of at least 300 Kg/mq.

27. A method for assembling and fixing a sheet metal covering system for roofs and the like, characterized in that it comprises the steps of:

-- providing a plurality of metal sheets (20), each of which has two opposite edges (18a, 18b) that are folded complementarily and are adapted to allow the coupling of two adjacent metal sheets (20) by partial overlap of said edges (18a, 18b) over a supporting and retention bracket (1);

-- providing a plurality of supporting and retention brackets (1), each of which has a longitudinal extension that is adapted to provide a contact surface for the edges (18a, 18b) of said metal sheets (20) and a transverse cross-section that is substantially symmetric with respect to a vertical axis, and being constituted by a footing (2) that is suitable for fixing to a load-bearing structure (50) and by a head (4) that is connected thereto and is contoured so as to have a bisymmetric transverse profile that is substantially rounded and comprises curved lateral surfaces (15a, 15b) that extend in a longitudinal direction and are adapted to make contact with surfaces (27a, 27b, 29) that are complementary thereto and are formed on said edges (18a, 18b) of said adjacent metal sheets and comprise, along their longitudinal extension, grooves (5a, 5b) that are adapted to interfere with corresponding folds (5c) formed on said edges (18a, 18b) of said adjacent metal sheets (20);

-- fixing said supporting and retention brackets (1) through the respective footings (2) to a supporting structure (50);

-- fixing said metal sheets (20) so that an edge (18b) of a metal sheet (20) is stably connected to the head (4) of said supporting bracket (1) and an edge (18a) that is complementary thereto of an adjacent metal sheet (20) overlaps the first sheet (20) and is also fixed to the head (4) of the bracket by way of the folds (5c, 25a, 25b, 35) that are complementary to the recesses (15c, 15d, 15e) of the head (4) and completely surrounds the head (4) of said bracket (1).

Drawing