High-strength metal grating for containment and protection, and machinery for its production.

Abstract

A high-strength protection grid is produced with a plurality of metal wires which are intercalated with metal ropes. The metal wires are interlaced with each other in interlacing portions, or are twisted in twists around the ropes in twisting portions. The interlacings between the wires and the twists of the wires with the ropes define the mesh of the grid. The interlacings and the twists are each unidirectional. The ropes have an external diameter which is greater than the wires and greater than 8 mm, preferably between 9 and 12 mm, even more preferably approximately of 10 mm. The grid is produced with a machine which is provided for the passage of ropes with such an increased diameter with respect to the ropes of the protection grids of the prior art.

Description

1 / 23 High-strength metal grating for containment and protection, and machinery for its production. Field of Invention

[001] The present invention relates to the field of high-strength civil works for containment and protection purposes, for example, for the construction of protective barriers against rockfalls or avalanches, for enveloping type linings for rock walls to contain rock displacements, for three-dimensional stabilization of land, escarpments, dams, embankments, tunnels and road constructions, for the construction of retaining walls for embankments, for the protection of the banks of water bodies, for the construction of dams and other protective barriers against debris along rivers and streams and hydraulic works in general, for the construction of gabions and other products made of metal grids and any other generally known civil and geotechnical use.

[002] The present invention was developed with particular attention to a metal protective and containment grid that is reinforced with metal cables. Technological Background

[003] Several types of metal grids are known for containment and protection, such as, for example, loose mesh grids, electro-welded grids, and hexagonal mesh grids with single, double, or triple twist. Each type of grid generally has a specific application according to the formation and technical characteristics of its metal components. Thus, for example, an electro-welded grid is normally composed of a plurality of straight bars with a large diameter, for example, 12 mm, having high tensile strength. The bars are positioned longitudinally and transversely and are welded to each other at the points of intersection to form an interlaced arrangement. Petition 870250080826, dated 09 / 09 / 2025, p. 40 / 72 2 / 23 with a square and / or rectangular mesh. These grids, although very strong, are very heavy and rigid, so they are not suitable for civil works where specific grid flexibility is required, for example, for wall cladding or other geotechnical works where the grid has to adapt to the soil formation.

[004] Another example of a protective grid, frequently used in civil works for protection against rockfalls, is a grid consisting of a plurality of transverse steel wires or cables positioned at an angle to each other and, preferably, perpendicularly. An example of this type of grid is illustrated and described in European Patent No. WO 2008 / 132654 of the same Applicant. The cables used in this type of grid can have a diameter of 10 to 12 mm and, at the points of intersection, are locked together by means of connecting devices of various types, the most common of which comprise pins or fixing plates or a pair of steel bars that are wound in highly tensioned spirals around the points of intersection of the cables. These grids exhibit high tensile strength and, at the same time, sufficient flexibility to absorb the energy of the bodies that strike them and that rest on them, such as, for example, stones, rocks or similar objects.One disadvantage of these grates is that the time required for their production is relatively long. Furthermore, the dimensions of these grates are generally modest, to the point that they are used for civil works with limited dimensions, for example, for so-called snow-retention umbrella systems or barriers against rockfall.

[005] As mentioned, each of the known grating types is particularly suited for use in specific conditions; in some cases, however, the use of the correct grating type may be inconvenient, disadvantageous, and very expensive. For example, a grating Petition 870250080826, dated 09 / 09 / 2025, page 41 / 72 3 / 23 for protection against rock falls, with characteristics of high tensile strength, although fully adequate for the purpose for which it was designed and intended, can be complex to transport due to its weight, dimensions, and the difficulty of compacting and folding it. It can also be expensive due to the material it is made of and the production process, and difficult to install due to its rigidity.

[006] Another disadvantage of the high-strength grids of the type mentioned above is that, although they ensure adequate resistance to impacts and thrust events applied, for example, by a rock mass, they do not guarantee complete safety if their mesh dimensions are such that they cannot retain rock fragments or other fine material. For this reason, it is also necessary to combine, in all types of grids described above, panels of metal grids with double-twisted hexagonal mesh that have smaller dimensions than the mesh of the main grids, which are electro-welded or produced with intersecting cables in order to generate a type of filter that retains the finest debris. However, this makes the installation of the containment structure more complex and expensive, including both the electro-welded grid or the crossed cable grid and the double-twisted grid.

[007] In generally different sectors, for example, for enclosing gardens or patios, for confining animals, or for covering wall structures to be plastered, and other similar applications where there is no need for a grid with high impact resistance, metal grids are known whose wires are interwoven in a very simple manner. In addition to conventional fencing grids, whose individual wires are bent helically and interwoven, grids are also known whose contiguous wires are wound together from a point in the middle of each mesh, so that ca Petition 870250080826, dated 09 / 09 / 2025, page 42 / 72 4 / 23 of the interlacing is formed by half a turn clockwise and another half turn counterclockwise. Examples of these grids are described in US Patents 1401557 and 2053221. Some embodiments provided for the introduction of a third wire in these interlaced fabrications so as to run in a straight line in the middle of each mesh of the grid. These grids are not suitable for civil uses in the geotechnical field, such as applications for earth or rock slope containment, or for protection against rockfalls, and cannot ensure reasonable strength and reliability after impacts, even modest ones. In fact, when applying a tension that may even have only a small value to the interlacing of the grid wires, in a direction transverse to the main direction in which the interlaced wires extend, the interlacing loosens and opens.In practice, the strength of the interlacing of these grids is given by the resistance that the wire applies to bending, which is much lower than the breaking load of the wire if it had to be torn to open the grid mesh, as in the high-strength grids mentioned above and which will be discussed later.

[008] Another type of high-strength metal grating for protection and containment is described in document US 6279858. This is a grating woven with corrosion-resistant wires, mounted on the ground surface or fixed in position, erected on a slope. The wires of this metal grating are made of steel with a nominal resistance between 1,000 and 2,200 MPa. The metal grating has a rhomboid mesh formed by individual wires helically bent and interwoven. The main disadvantage of this grating is the cost, since it is entirely made of high-strength steel wires, a high cost in itself. In addition, the simple interweaving of the grating wires makes it vulnerable to breakage, even of just one of the wires which can thus become completely detached from the adjacent wires, resulting in an opening. Petition 870250080826, dated 09 / 09 / 2025, p. 43 / 72 5 / 23 complete of the grid itself, which irreparably compromises its functionality and safety.

[009] Another type of high-strength containment and protection grid consists of structures comprising a combination of wires and metal cables. An example of such grids is the structure commercially known as Steelgrid® HR, produced by the Applicant, Officine Maccaferri SpA. Several variants of these grids are described in patents EP 1680552 and EP2475477 by the Applicant. They involve a grid structure with double-twisted interwoven metal wires, forming a hexagonal mesh, reinforced by longitudinal metal cables that replace several metal wires in the grid's weave. The metal cables of the Steelgrid® HR grids have a maximum diameter of 8 mm and a maximum tensile strength of 1770 MPa, being interwoven with the metal wires at nominal distances of 300 mm, 500 mm and 1000 mm from each other, while the nominal transverse pitch of the mesh formed by the metal wires can be 80 mm.These grates can be produced using the usual machines employed in the manufacture of conventional double-twist metal grates.

[0010] These protective and containment grids, which combine the versatility of a double-twist grid with the added strength provided by metal cables, are considered particularly effective and appreciated by the market. However, these grids are unable to meet a number of specific requirements due to intrinsic limitations arising from their construction.

[0011] One problem encountered in the production of these known grids, in which metal wires are interwoven with metal cables, is the fact that, in order to obtain substantial linearity of the cables that ensures better levels of grid strength performance, it is necessary to tension the cables downstream of the beam, i.e., the Petition 870250080826, dated 09 / 09 / 2025, page 44 / 72 6 / 23 cylinder that pulls the woven grid after the metal wires have been intertwined with the metal cables. However, this tension applied to the cables downstream of the beam causes a transverse narrowing of the grid, which brings two main negative consequences. On the one hand, the width of the grid is smaller than the nominal dimensions, which involves less transverse coverage of the grid compared to the design data and a higher weight per unit area, with consequent higher transportation costs and difficulty of installation as a result of the need to use a greater number of grid coils to cover the same surface area. Among other things, the value of grid narrowing cannot be predicted with certainty and may vary from one production batch to another, with the result that specific grid supplies may be rejected by the customer for not conforming to the design specifications.

[0012] Another negative consequence caused by the narrowing of the grid downstream of the beam, after the wires and cables have been woven, is the impossibility of correctly inserting the transverse cables into the grid to increase their transverse strength. During production, the transverse cables need to be introduced into the grid immediately downstream of the weaving, before the grid is tensioned by the beam. In this position, the grid has a nominal width that corresponds to the intended width, however, the longitudinal cables are not yet tensioned and exhibit undulations. Inserting a transverse cable in this grid condition would provide a cable section with a length equal to the nominal length. As a result of the narrowing of the grid downstream of the beam, however, the length of the transverse cable exceeds the width of the grid that is subject to narrowing, with the result that the transverse cable forms undulations to compensate for the reduced width of the grid.These. Petition 870250080826, dated 09 / 09 / 2025, p. 45 / 72 7 / 23 Transverse undulations deform the grid, which therefore becomes poorly rolled and difficult to transport, resulting in reduced performance levels, at least in the transverse direction, when put into operation. Declaration of Invention

[0013] One objective of the present invention is to overcome the aforementioned disadvantages of known types of metal containment and protection grids by providing a metal grid that is reinforced by metal cables and that substantially maintains the predetermined nominal flatness and width after weaving, wherein the metal cables are substantially straight with minimal undulations even during production, when the metal wires are interwoven with each other and, at predetermined intervals, with the metal cables.

[0014] Another objective of the invention is to provide a metal grid, particularly of the double-twist type, which is reinforced by metal cables that develop in a relatively straight line in the longitudinal direction, with the possibility of adding to it, during production, transverse cables which, when the grid is finished, are likewise relatively straight in the transverse direction of the grid, so that the grid, once manufactured, has no relevant individual undulations in either the longitudinal or transverse direction, while at the same time being sufficiently flexible to adapt to the formation of soil fragments, embankments, slopes, escarpments and, in general, various formations in the geotechnical sector.

[0015] Another objective of the invention is to provide a metal grate, in particular of the double-twist type, which is reinforced by metal cables that can withstand high tensile forces and which, at the same time, is flexible, lightweight and easy to handle.

[0016] Another objective of the present invention is to provide a grid Petition 870250080826, dated 09 / 09 / 2025, page 46 / 72 8 / 23 metallic, in particular of the double-twist type, for protection in the geotechnical field that is economical and quick to manufacture, whose manufacturing process can be mechanized and automated without using particularly complex or extremely expensive machinery in relation to the machinery known for the production of known protective gratings.

[0017] To achieve the objectives indicated above, the invention relates to a metal protective grid according to claim 1. The invention also relates to a machine that is particularly suitable for manufacturing such a grid.

[0018] According to a first aspect, a protective grid for civil works is described, produced with a plurality of metallic wires interspersed with metallic cables, wherein the metallic wires are interwoven with each other in interwoven portions of wires or are twisted around the cables in interwoven portions which, for ease of description, are defined in this report as interwoven portions of cables, even if it is the wire to be twisted with twists of the same with the cable, while the cable remains extended as much as possible, substantially straight or with a slightly wavy progression. The interweaving between the wires and the twists of the wires with the cables define the grid mesh, in which the interweaving and twists are unidirectional and the cables have an outer diameter greater than that of the wires and greater than 8 mm. Preferably, the cables have an outer diameter between 9 and 12 mm, except for the usual dimensional tolerances of such cables.Even more preferably, the cables have an outer diameter of approximately 10 mm, except for the usual dimensional tolerances for such cables. Metallic cables may have a protective outer covering of plastic material which contributes to the formation of the total outer diameter of the cable. Petition 870250080826, dated 09 / 09 / 2025, p. 47 / 72 9 / 23

[0019] Based on experiments conducted by the Applicant, it was surprisingly discovered that a cable with a diameter greater than 8 mm, preferably between 9 and 12 mm, and even more preferably approximately 10 mm, exits the interlacing and weaving zone with the metal wires in a substantially straight state, even before the beam of a metal grating weaving machine. This confirms that a larger diameter of the metal cable promotes the maintenance of its linearity and, therefore, of the nominal width of the grating without it being subjected to a narrowing downstream of the beam caused by the straightening of the cables, which is desirable to ensure high levels of grating strength performance. In fact, it was found that the more the cables are extended, i.e., straight or virtually straight, the greater the resistance to impacts or debris containment by the protective grating.

[0020] According to a specific aspect, the protective grid may comprise cables with an ultimate tensile strength greater than approximately 1000 MPa, preferably greater than 1500 MPa, even more preferably greater than or equal to approximately 1700 MPa. The cables may be of various types and, in some embodiments, may be helical cables.

[0021] According to another aspect, a machine for manufacturing a protective grid of the type indicated above is described. The machine comprises a series of pairs of first guide devices, spaced apart and coaxial, positioned in rows parallel to the axis of a drum, and a series of pairs of second guide devices, spaced apart and coaxial, positioned on the other side of the plane of symmetry tangent to the drum. Each pair of second guide devices can be positioned specularly opposite, with respect to the plane of symmetry, to one of the pairs of first guide devices. The pairs of first and second devices are simultaneously and alternately Petition 870250080826, dated 09 / 09 / 2025, page 48 / 72 10 / 23 moving parts in half-steps in opposite directions, parallel to the drum axis. On the machine, the minimum distance between guide devices of the same type in a cable passage zone is greater than 8 mm, preferably greater than or equal to approximately 10 mm, even more preferably greater than or equal to approximately 12 mm, for example, 13 mm or more. Brief Description of the Drawings

[0022] Additional features and advantages will be recognized from the following detailed description of a preferred embodiment with reference to the accompanying drawings, which are provided only as a non-limiting example and in which: Figure 1 is a perspective view, partially in section, of part of a machine for manufacturing a protective grid that incorporates features of the present invention, in which parts of this grid can also be seen; Figure 2 is a longitudinal cross-sectional view of a part of the machine in Figure 1; and Figure 3 is a longitudinal cross-sectional view of a detail of the machine in Figure 1. Detailed Description

[0023] The following embodiments describe features that allow the implementation of the invention. The described features can be combined with each other in various ways and are not necessarily limited to the precise embodiment to which the drawings and relevant description refer. In other words, those skilled in the art, when reading the following description, will know how to obtain the items of information that are advantageous for understanding how to implement one or more of the described features by combining them with one or more of the other described features, without the specific wording of the description, paragraphs, terms or Petition 870250080826, dated 09 / 09 / 2025, page 49 / 72 11 / 23 drawings constitute a limitation on the possibility of isolating one or more of the described and illustrated features to combine them with one or more of any other described and illustrated features. In more detail, in this description it should be understood as expressly described any combination of any two expressly described features, even in the case where the features are individually extracted from the specific context in which they may be side by side or combined with other different features, taking into account the skills and knowledge of a technician in the field who understands the possibility of functionally combining the features without it being necessary to functionally apply the other different features.Unless otherwise specified, any and all elements, members, means, systems, components, or objects described and illustrated herein shall be understood as autonomously and individually modifiable and separable / combinable with any other element, member, means, system, component, or object described and illustrated. The materials, forms, and functions described and illustrated do not limit the present invention, but are presented only to enable those skilled in the art to understand and carry out the invention according to preferred, though not exclusive, embodiments.

[0024] Now with reference to Figure 1, a partially sectioned perspective view is illustrated of a part of a machine 10 for manufacturing a protective grid 12, in particular a metal protective grid in the area of ​​civil works, such as barriers against rockfalls or avalanches, debris dams for watercourses, wraparound coverings and other works for the protection of escarpments or rocky terrain, and the like.

[0025] In more detail, the protective grid 12 comprises a Petition 870250080826, dated 09 / 09 / 2025, page 50 / 72 12 / 23 a set of interwoven metal wires 14 to form a series of meshes 16. In the embodiment illustrated in the Figures, the meshes 16 have a virtually hexagonal shape. The dimensions of the hexagonal mesh are generally known and standardized in the field of double-twisted metal grids and do not constitute, in any case, a limitation of the present invention, which can be implemented with hexagonal meshes of any type and kind, and with a generally known width-to-height ratio which, in the field, is generally around values ​​between approximately 0.70 and approximately 0.85, for example, - at least nominally approximately 0.75 (for a 60 x 80 mm mesh), approximately 0.80 (80 x 100 mm mesh) and approximately 0.83 (100 mm x 120 mm mesh).

[0026] The metal wires 14 are generally positioned lengthwise in a preferred longitudinal direction of the protective grid 12. The metal wires 14 are interwoven in wire interweaving portions 18. These wire interweaving portions 18 are defined by the sections of the respective metal wires 14 that are braided into each other more than once in a unidirectional twist direction, i.e., in a single direction, clockwise or counterclockwise, for each wire interweaving portion 18. This type of interweaving, which is defined as being double twist, is particularly strong and stable and allows the production of protective grids with a secure and resistant mesh.

[0027] Interspersed between the set of metallic wires 14, at predetermined intervals, are metallic cables 20 which have greater resistance compared to the metallic wires 14. The metallic cables 20 generally exhibit a less wavy progression than the metallic wires 14 and, in particular, follow a direction that is as straight as possible or slightly wavy in order to contribute predominantly Petition 870250080826, dated 09 / 09 / 2025, pp. 51 / 72 13 / 23 concerning the resistance of the protective grid 12 after an impact on the grid itself, for example, by rocky material from a landslide. As can be seen in Figure 1, where, for simplicity, only a part of the protective grid 12 with a metal cable 20 is illustrated, the metal cable 20 is preferably maintained, as far as possible, in a straight state with respect to the preferred longitudinal direction of the protective grid 12. In the example of Figure 1, it can be clearly seen that the metal wires 14 adjacent to the metal cable 20 are wound around the cable 20 in cable braid portions 22. These cable braid portions 22 are defined by the sections of metal wires 14 that are again twisted more than once around the cable in a unidirectional twist direction, i.e., in a single direction, clockwise or counterclockwise, for each cable braid portion 22.The metal wires 14 interweave with the metal cable 20, which has transverse undulations in relation to the preferred longitudinal direction that are much less pronounced than those of the metal wires 14 and, in particular, are virtually straight or wavy, as we have just mentioned. Therefore, the metal wires 14 form a so-called half mesh 24 which can assume, in the protective grid in which the interwoven metal wires form a hexagonal mesh, the characteristic shape of a semi-hexagon.

[0028] The protective grid 12, which can be made of metal wires 14, constructed, for example, of common steel, with a diameter of 2 to 3 mm or larger, for example, also 4 to 5 mm, is flexible and easily transportable. Naturally, the wires 14 can be replaced totally or partially by thin metal cables, for example, with a diameter of approximately 2 to 5 mm, which is much smaller than the diameter of the larger metal cables 20. Petition 870250080826, dated 09 / 09 / 2025, pp. 52 / 72 14 / 23

[0029] The metal wires 14 and the larger metal cables 20 may be covered by a protective covering, for example, a covering made of plastic material that prevents or at least reduces the corrosion of wires and / or cables.

[0030] According to a particularly advantageous feature, metal cables 20 with a larger diameter have a total diameter, including the potential protective covering, greater than 8 mm and preferably between 9 and 12 mm, even more preferably approximately 10 mm, naturally except for the typical dimensional tolerances in the area of ​​metal cable manufacturing. The strength characteristics of such a grid are substantially greater than those of a grid of the known type with cables having a diameter less than or equal to 8 mm for the same tensile strength per mm2 of the cables.A protective grid constructed of 20-gauge metal cables with a diameter greater than 8 mm, preferably between 9 and 12 mm, and even more preferably approximately 10 mm, is, in any case, sufficiently flexible to be rolled up and transported to the installation site, but sufficiently rigid, once stretched, to construct protective structures with relative dimensional stability. This is particularly advantageous, for example, in wraparound roofs, where the protective grid is positioned over a rocky wall to retain rock material that detaches from it.

[0031] Furthermore, it has been experimentally discovered that, using a metal cable with a diameter greater than 8 mm, preferably between 9 and 12 mm and, even more preferably, approximately 10 mm, it is much simpler to keep the cable 20 taut during the production of the grate due to the intrinsic rigidity of a metal cable with such an outer diameter, both with and without protective coating. This is particularly advantageous for the construction of grates. Petition 870250080826, dated 09 / 09 / 2025, page 53 / 72 15 / 23 of protection 12 since, the straighter the cables 20 incorporated into the grid, the greater the total resistance of the grid against impacts, since the cables 20, which are already substantially stretched, are practically immediately propelled by the tension, long before the metal wires of the grid are propelled. In other words, the impact force applied to the protective grid 12 is absorbed to its maximum extent almost immediately by the cables 20, while the residual impact force, which is of reduced intensity, can be distributed more evenly over the surface of the grid formed by the interwoven metal wires.

[0032] Preferably, the metal cables 20 have an ultimate tensile strength greater than approximately 1000 MPa, preferably greater than 1500 MPa, and even more preferably greater than or equal to approximately 1700 MPa. Cables with an ultimate tensile strength of approximately 1770 MPa have been found to be particularly effective, although cables with an ultimate tensile strength of up to 2200 MPa and greater can also be used successfully. Naturally, the use of metal cables 20 with a diameter greater than 8 mm, greater than the diameter of the cables normally used in similar protective grids of the prior art, allows the use of steels with a unit ultimate tensile strength lower than the known strength, being possible, in any case, at least to equal, if not exceed, the total strength of the metal cables used in the grids of the prior art.

[0033] A cable that proves particularly effective for constructing the grid of the present invention is a galvanized helical cable with a nominal diameter of 10 mm, formed by a strand composed of 19 steel wires with a maximum tensile strength of 1770 MPa, resulting in a minimum tensile strength of 93,166 kN. The cable is included in the specifications of the EN12385-10 standard. Naturally, Petition 870250080826, dated 09 / 09 / 2025, pp. 54 / 72 16 / 23 Different types of cables can also be used, for example, with a plurality of wires, with a core, etc. In any case, a fundamental aspect identified by the Applicant is that the stronger the cable, the fewer undulations will occur in the production of the grid. Therefore, the use of a cable with a larger diameter than that used in known large structures promotes flatness. In this context, the use of a helical cable or a high-quality cable, i.e., with high ultimate tensile strength, for example, as indicated above, ensures an adequate benefit in terms of flatness, even with cables with diameters slightly larger than 8 mm.

[0034] The protective grid 12 described above cannot be produced with currently available machines, which are not capable of receiving a cable with an outer diameter greater than 8 mm. Therefore, an objective of the present invention is also to provide a specific machine for the manufacture of a protective grid 12 with the characteristics mentioned above. The machine intended for the production of a grid with the characteristics described above is partially similar to a known machine for the packaging of conventional double-twist grids. In the following description, although reference is made to the machine as a whole, the focus will therefore be more extensive on the new and original elements that allow the production of a grid with reinforcing cables with a diameter greater than 8 mm.

[0035] As can be seen in Figure 1, the machine 10 comprises a drum or beam 32 which is mounted with devices (not shown) on the fixed casing of the machine so as to be able to rotate synchronously with the speed of the wire interlacing devices 14 at a constant speed in the direction of the arrow 34 around the T-axis thereof. Radial projections or pins 38 extend to Petition 870250080826, dated 09 / 09 / 2025, page 55 / 72 17 / 23 outside the curved face 36 of the drum. These pins are positioned in rows that extend in a direction parallel to the T-axis and are positioned at identical angular intervals. In each row, the pins 38 are positioned with a constant spacing and two successive rows are staggered relative to each other by a half step in the axial direction. These pins are used to form the grid with hexagonal mesh and to retain a portion of the grid already formed in the discharge direction of the machine.

[0036] The means of interlacing and / or interconnecting the metallic wires and cables comprise a series of pairs of first guide devices, which are partially spaced apart and coaxial and which are positioned in parallel rows with respect to the axis of the drum 32 on one side of the plane of symmetry tangent to the cylindrical periphery of the beam 32. The pairs of guide elements are positioned in radial planes with respect to the beam and their pitch is identical to the pitch of the pins 38. The means of interlacing and / or interconnecting the metallic wires and cables further comprise a series of pairs of second guide devices which are partially spaced apart and coaxial and which are positioned on the other side of the plane of symmetry tangent to the drum 32. Each pair of second guide devices is positioned specularly opposite, with respect to the plane of symmetry, to one of the pairs of first guide devices.The first and second pairs of devices are simultaneously movable, alternately, in half-steps, in opposite directions parallel to the axis of drum 32. During use, rotation around the axis of the guide devices generates the interlacing of the threads, while movement parallel to the axis of drum 32 of the first and second pairs of guide devices, in the opposite direction, generates the hexagonal mesh. The interlacing means are naturally coordinated, in terms of movements, with the movement of the beam, in order to perform the weaving. Petition 870250080826, dated 09 / 09 / 2025, pp. 56 / 72 18 / 23 grade as a whole.

[0037] In more detail, under drum 32 are provided two pairs of bars 40, 42 and 44, 46 which are parallel to axis T and which serve as support for rotating semi-cylindrical bodies 60, 62, 64 and 66; the function of the semi-cylindrical bodies is to twist the wires and cables in pairs together to produce grid 12.

[0038] Bars 40, 42 and 44, 46 have, in cross-section, a U-shaped profile rotated 90°. The bars are positioned in pairs, with the respective open edges of the U facing each other and located in a vertical plane of symmetry tangent to the periphery of drum 32; bars 40 and 42 form an upper pair and bars 44 and 46 form a lower pair. Naturally, the terms upper and lower indicate the position in which the bars are positioned in the embodiment of the Figures. In fact, however, it is not excluded that they may be positioned differently, for example, with the wires and cables sliding mainly in the horizontal and vertical directions, as illustrated in Figure 2. More generally, an upper bar is downstream in the working direction relative to a corresponding lower bar, regardless of the height at which it is located.

[0039] The bar pairs 40, 42 and 44, 46 are supported by elements 50, 52, 54, 56 which are part of the fixed housing of the machine 10. In addition, they can move in a direction parallel to the direction of the T-axis. The upper bars 40 and 42 are similar to the bars 44 and 46 of the lower bar pair. On the edges of each of the bars 40, 42, 44, 46, semi-cylindrical seats are formed with an axis perpendicular to the T-axis, in each of which a respective semi-cylindrical rotating body 60, 62, 64, 66 is housed. The distance between each seat and the adjacent seat on the same bar is substantially equal to the distance between the pins 38. Petition 870250080826, dated 09 / 09 / 2025, pp. 57 / 72 19 / 23

[0040] The semi-cylindrical rotating bodies 62, which are received in the upper bar 42, are aligned with the semi-cylindrical rotating bodies 66 of the lower bar 46, and each has a respective through hole 72 and 76 with an axis parallel to the axis of the corresponding semi-cylindrical rotating body. The through holes 72 and 76 are also aligned. The holes 72 and 76 are traversed by wires 14 to be fed to the grid in a formation, as described in more detail below.

[0041] In the region of the position where it is desirable to insert a cable 20 into the grid 12, upper semi-cylindrical rotating bodies 160, 162 and lower semi-cylindrical rotating bodies 164, 166 are provided which are of a different type from those used for the passage of wires 14 and which are modified to allow the passage of cables with a large diameter as indicated above, i.e. greater than 8 mm and, preferably, although not limiting, up to 12 mm, in order to produce the grid described above, as will become clearer below.

[0042] A cylindrical container 90 containing a predetermined length of helically wound wire 14 can be mounted under each semi-cylindrical body 60 and 160, which is supported by the upper bar 40. The wires 14 exit the containers 90 from the top, pass through the through holes 70 and feed into the machine to form the grid. During use, the cylindrical containers 90 rotate around the adjacent wires 14 or cables 20.

[0043] The pairs of bars 40, 42 and 44, 46 are connected to motion mechanisms that allow, simultaneously, the two bars 42, 46, one on top of the other, and the two bars 40, 44, one on top of the other, to move in translation in the same direction parallel to the axis T of drum 32, but with opposite orientations, respectively. The motion mechanisms are configured so that each body Petition 870250080826, dated 09 / 09 / 2025, pp. 58 / 72 20 / 23 semi-cylindrical body, which is supported by the same bar, can be moved in translation from a position where it faces a first semi-cylindrical body of the bar facing the same to a second position where it faces a second semi-cylindrical body adjacent to the first semi-cylindrical body.

[0044] Furthermore, the semi-cylindrical rotating bodies are connected by means of racks, such as 100, 102 visible in Figure 1, to rotating mechanisms that rotate them in pairs to interlace two adjacent wires 14 with each other or to twist a wire 14 with a cable 20 and thus generate a portion that is twisted to gradually define the mesh of the protective grid 12.

[0045] As indicated above, the upper semi-cylindrical bodies 160, 162 and the lower rotating semi-cylindrical bodies 164, 166, used for twisting the wires 14 with the cable 20, are modified in relation to those used for intertwining the metal wires 14 separately. As can be seen in Figure 2, the lower rotating semi-cylindrical bodies 166, through which the cable 20 passes, have a through hole 176 with a diameter greater than 8 mm, preferably greater than or equal to 10 mm, even more preferably greater than or equal to 12 mm, for example, 13 mm or more. This allows the passage of a cable 20 with an outer diameter greater than 8 mm and, preferably, up to 12 mm. Naturally, the semi-cylindrical bodies 66, through which the smaller diameter wires 14 pass, may also have holes with a larger diameter, preferably identical to the diameter of the holes 166.In this way, machine 10 can be used to produce protective grids 12 with cable arrangement 20 as desired.

[0046] The upper semi-cylindrical bodies 160, under which the cylindrical containers 90 are mounted, are produced in such a way that, between a cylindrical container 90 and the adjacent container, Petition 870250080826, dated 09 / 09 / 2025, pp. 59 / 72 21 / 23 a passage space greater than 8 mm is available for cable 20, preferably greater than or equal to 10 mm and, even more preferably, greater than or equal to 12 mm, for example, 13 mm or greater. In this way, during the rotational movement of the cylindrical containers 90 around the cable 20, during the twisting of a wire 14 around the cable 20 in order to produce a wire interlacing portion 22, the passage of the cable 20 between two adjacent cylindrical containers 90 is ensured without any interference. The upper semi-cylindrical body 162 has an enlarged opening 163 into which the cable 20 is inserted with a slight inclination in order to move the cable 20 towards the wire 14 while twisting it around the cable.The engagement of the various semi-cylindrical bodies in the racks 100, 102 is configured in such a way that at least the semi-cylindrical body 162 has a diameter sufficient to be able to form a through hole 172 with a diameter greater than 8 mm, preferably greater than or equal to 10 mm and, even more preferably, greater than or equal to 12 mm, for example, 13 mm or greater, so as to allow the passage of the cable 20 with increased diameter, as described above.

[0047] As can be better seen in Figure 3, the pairs of upper semi-cylindrical bodies 60 and 160 are spaced apart by an extension A that corresponds to the mesh width of the grid 12. This extension is given and does not change in relation to double-twist grids, both simple and reinforced by cables, of known type. To allow the production of double-twist grids with cables 20 of increased diameter, as indicated above, the through hole 172 in the upper semi-cylindrical body 162 is formed with a diameter B greater than 8 mm up to 12 mm or slightly larger. The through hole 170 in the upper semi-cylindrical body 160 can have a diameter C smaller than 8 mm since, from this hole, only a single wire will always come out. Petition 870250080826, dated 09 / 09 / 2025, pp. 60 / 72 22 / 23 metallic 14, which is helically received into the cylindrical container 90 under the lower semi-cylindrical body itself. As indicated above, the minimum distance D between two adjacent semi-cylindrical containers, particularly, but not exclusively, where there is provision for the passage of a cable 20, is configured so as not to be less than 8 mm and, preferably, 12 mm or greater.

[0048] As a result of the machine 10 described above, it is possible to reinforce the protective grid 12 with cables with an outer diameter generally greater than 8 mm, both with and without protective plastic coating, maintaining a hexagonal mesh with conventionally known and preferred dimensions of 5 x 7, 6 x 8, 8 x 10, 10 x 12 and 12 x 14 mm. The preferred distance between two adjacent cables 20 may be between 25 cm and 100 cm or even more. The total lateral dimension of the grid is preferably between 2 and 5 m.

[0049] A particularly advantageous feature of the present invention is the fact that the machine 10 allows the production of a protective grid 12 in which the cables 20, in addition to having a larger diameter and therefore greater resistance than those that can be used in known protective grids, are also straighter upstream of the beam, thus improving the performance levels of the protective grid after an impact, but avoiding, in particular, a narrowing of the grid downstream of the beam in relation to the nominal transverse dimension.In fact, as explained above, cables with a diameter greater than 8 mm of the grid described above, preferably between 9 mm and 12 mm, and even more preferably approximately 10 mm, maintain their linearity, without undulations or extremely small undulations upstream of the beam. This prevents the resulting grid from being subjected to the narrowing that occurs in grids of the type known for cable straightening downstream of the beam. Thanks to this characteristic... Petition 870250080826, dated 09 / 09 / 2025, pp. 61 / 72 23 / 23 tica, it is also possible to introduce 12 transverse cables into the protective grid without this causing a ripple in the grid due to the narrowing of the grid. In particular, it is advantageous to insert the transverse cables immediately downstream of the discharge of the wires or cables of the semi-cylindrical rotating bodies 60, 62, 160 and 162, as indicated by the contour of the transverse cable Z, indicated by a thin line in Figure 3, whose diameter is smaller than the distance E between the axis of the discharge holes of the wires or cables of the aforementioned semi-cylindrical rotating bodies 60, 62, 160 and 162.

[0050] If transverse Z cables are used, there is the added advantage that the impact force applied to the guardrail 12 is absorbed to the maximum, almost immediately, by both the longitudinal cables 20 and the transverse Z cables, with an immediate containment effect in both directions.

[0051] Naturally, while the principle of the invention remains the same, the embodiments and details of construction may vary widely from those described and illustrated, without thereby departing from the scope of the present invention. Petition 870250080826, dated 09 / 09 / 2025, pages 62 / 72

Claims

1 / 2 CLAIMS 1. High-strength protective grid for civil and geotechnical uses, characterized in that it is produced with a plurality of metal wires (14) that are interleaved with metal cables (20), each individual metal wire being interlaced with another individual metal wire in interlaced portions of wires (18), or being twisted in twists around an individual cable in interlaced portions of cables (22), the interlacing between the wires and the twists of the wires with the cables defining the grid mesh, wherein the interlacing and twists are each unidirectional and wherein the cables have an outer diameter that is greater than the wires and greater than 8 mm.

2. Protective grid, according to claim 1, characterized in that the cables (20) have an outer diameter between 9 and 12 mm.

3. Protective grid, according to claim 2, characterized in that the cables (20) have an outer diameter that is approximately 10 mm.

4. Protective grid, according to any one of claims 1 to 3, characterized in that the cables (20) have an outer protective covering of plastic material which contributes to the total outer diameter of the cable.

5. Protective grid, according to any one of claims 1 to 4, characterized in that the cables (20) have an ultimate tensile strength greater than approximately 1000 MPa, preferably greater than 1500 MPa, even more preferably greater than or equal to approximately 1700 MPa.

6. Protective grid, according to any of the preceding claims, characterized in that the cables (20) are helical cables. Petition 870250080826, dated 09 / 09 / 2025, page 64 / 72 2 / 2 7. Protective grating, according to any of the preceding claims, characterized in that the grating is substantially flat.

8. Protective grid, according to any of the preceding claims, characterized in that it comprises transverse cables (Z) that are interwoven with the grid mesh.

9. A manufacturing machine for a protective grid, as defined in any of the preceding claims, comprising a series of pairs of first guide devices, which are spaced apart and coaxial, and which are positioned in rows parallel to the axis of a drum, and a series of pairs of second guide devices, which are spaced apart and coaxial, and which are positioned on the opposite side of the plane of symmetry that is tangent to the drum, each pair of second guide devices being positioned specularly opposite, with respect to the plane of symmetry, to one of the pairs of first guide devices, wherein the pairs of first and second devices are simultaneously movable by half a step in opposite directions parallel to the axis of the drum, characterized in that the minimum distance (D) between the guide devices in a cable passage zone is greater than 8 mm.

10. Machine according to claim 9, characterized in that the minimum distance between the guide devices is greater than or equal to 10 mm, preferably greater than or equal to 12 mm, even more preferably 13 mm or more. Petition 870250080826, dated 09 / 09 / 2025, pp. 65 / 72

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