METAL MESH AND METHOD FOR MANUFACTURED A FILAMENT FOR METAL MESH

Description

State of the art

[0001] The invention relates to a wire mesh according to the preamble of claim 1 and a method for producing a helix for a wire mesh according to the preamble of claim 10.

[0002] From CH 703 929 A2, wire meshes with interwoven wire coils are known, at least one of which is bent from a single wire, and wherein each wire coil comprises a first leg, a second leg, and a bend connecting the first and second legs. Such wire coils are produced by repeatedly bending a wire in a bending direction and have a spiral shape. The bending is carried out using a bending table that bends the wire around a bending mandrel. The wire is fed obliquely to the bending mandrel by means of suitable feed rollers that guide the wire along its longitudinal sides.

[0003] The object of the invention is, in particular, to provide a generic wire mesh with advantageous properties with regard to load-bearing capacity. This object is achieved according to the invention by the features of claims 1 and 10, while advantageous embodiments and further developments of the invention can be found in the dependent claims. Advantages of the invention

[0004] The invention relates to a wire mesh, in particular a safety net, with several interwoven helixes, at least one of which is bent from at least one single wire, a wire bundle, a wire strand, a wire rope and / or another longitudinal element with at least one wire, in particular a high-strength steel, and comprises at least one first leg, at least one second leg and at least one bending point connecting the first leg and the second leg.

[0005] It is proposed that the longitudinal element, in particular the wire, is bent at least substantially without torsion or without twisting along a course of the first leg and / or the second leg.

[0006] The design of the wire mesh according to the invention allows for a particularly high load-bearing capacity. Advantageously, a wire mesh with high tensile strength can be provided. Furthermore, breaks in the mesh, for example due to impacts from objects, can be reduced. Additionally, the strength of the wire used in production can be at least largely maintained. In particular, the tensile strength, brittleness, flexural stiffness, and / or breaking strength of the wire used in production are only minimally or at least partially altered during manufacturing. Advantageously, the frequency of wire breaks in the production of high-strength wire meshes can be reduced or wire breaks avoided altogether. Furthermore, manufacturing inaccuracies due to material irregularities and / or residual stresses can be reduced.

[0007] In this context, "wire" shall be understood to mean, in particular, an elongated and / or thin and / or at least mechanically bendable and / or flexible body. Advantageously, the wire has a cross-section that is at least substantially constant along its longitudinal direction, in particular circular or elliptical. A round wire is especially advantageous. However, it is also conceivable that the wire is formed, at least partially or entirely, as a flat wire, a square wire, a polygonal wire, and / or a profile wire. For example, the wire may be made, at least partially or entirely, of metal, in particular a metal alloy, and / or organic and / or inorganic plastic, and / or a composite material, and / or an inorganic non-metallic material, and / or a ceramic material.For example, the wire could be designed as a polymer wire or a plastic wire. In particular, the wire could be designed as a composite wire, such as a metal-organic composite wire, a metal-inorganic composite wire, a metal-polymer composite wire, a metal-metal composite wire, or the like. It is particularly conceivable that the wire comprises at least two different materials, which are arranged relative to each other, particularly according to a composite geometry, and / or are at least partially mixed together. Advantageously, the wire is designed as a metal wire, in particular as a steel wire, and especially as a stainless steel wire. If the helix has several wires, these are preferably identical. However, it is also conceivable that the helix has several wires that differ, in particular, with regard to their material, diameter, and / or cross-section.Preferably, the wire has a particularly corrosion-resistant coating and / or sheathing, such as a zinc coating and / or an aluminum-zinc coating and / or a plastic coating and / or a PET coating and / or a metal oxide coating and / or a ceramic coating or the like. The longitudinal element of the wire is advantageously coated.

[0008] Advantageously, the transverse extent of the helix is ​​larger, particularly considerably larger, than the diameter of the wire and / or the diameter of the longitudinal element from which the helix is ​​made. Depending on the application, and especially on the desired load-bearing capacity and / or the desired spring properties of the wire mesh, particularly in the frontal direction, the transverse extent can be, for example, two, three, five, ten, or twenty times the diameter of the longitudinal element, with intermediate values, smaller values, or larger values ​​also being conceivable. Similarly, depending on the application, the wire can have a diameter of, for example, approximately 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, or even more or less, or a diameter of an intermediate value.Larger, and in particular significantly larger, diameters are also conceivable if the longitudinal element comprises several components, especially several wires, as in the case of a wire rope, strand, bundle of wires, or the like. A "principal extension plane" of an object is understood to be, in particular, a plane that is parallel to a largest side face of the smallest imaginary cuboid that just completely encloses the object, and in particular passes through the center of the cuboid.

[0009] In particular, wire mesh is used for slope stabilization, safety fencing, debris fences, rockfall protection nets, barrier fences, fish farming nets, predator protection nets, enclosure fences, tunnel protection, landslide protection, motorsport safety fencing, road fences, avalanche protection, and similar applications. Due to its high strength and / or load-bearing capacity, it is also suitable for covering and / or encasing structures such as power plants, factories, residential buildings, and other buildings, as well as for explosion protection, projectile protection, shielding against flying objects, safety nets, crash barriers, and similar purposes. The wire mesh can be laid, arranged, and / or mounted horizontally, vertically, or diagonally, especially relative to a substrate. In particular, the wire mesh is typically applied in a flat, sheet-like form.Advantageously, the wire mesh is regularly structured and / or periodically in at least one direction. Preferably, the wire mesh is rollable and / or unrollable, particularly around an axis that runs parallel to the main direction of extension of the helix. In particular, a roll formed from the wire mesh is unrollable in a direction perpendicular to the main direction of extension of the helix.

[0010] Advantageously, the wire mesh has a large number of meshes, especially those of identical design. The helixes form the meshes particularly advantageously.

[0011] Preferably, the helix is ​​spirally formed. In particular, the helix is ​​formed as a flattened spiral. Advantageously, the helix has a diameter and / or cross-section that is at least substantially constant or constant along its length. Preferably, the helix and / or the wire and / or the longitudinal element has a circular cross-section. Particularly preferably, the helix has a plurality of legs, which are advantageously at least substantially identical or identical in form. Preferably, the helix is ​​formed from a single, in particular uninterrupted, wire.

[0012] In this context, "at least substantially identical" objects are understood to mean, in particular, objects that are designed in such a way that they can each fulfill a common function and that, apart from manufacturing tolerances, differ in their design only by individual elements that are insignificant for the common function. Preferably, "at least substantially identical" is understood to mean identical apart from manufacturing tolerances and / or within the limits of manufacturing possibilities. In this context, "at least substantially constant value" is understood to mean, in particular, a value that varies by no more than 20%, advantageously by no more than 15%, particularly advantageously by no more than 10%, preferably by no more than 5%, and most preferably by no more than 2%.The requirement that an object has a "cross-section that is at least substantially constant" shall be understood in particular to mean that for any first cross-section of the object along at least one direction and any second cross-section of the object along the direction, the minimum area of ​​a difference area formed by superimposing the cross-sections shall be a maximum of 20%, advantageously a maximum of 10%, and particularly advantageously a maximum of 5% of the area of ​​the larger of the two cross-sections.

[0013] In particular, the helix has a longitudinal direction. Preferably, the longitudinal direction of the helix is ​​arranged at least substantially parallel to, or parallel with, a principal extension direction of the helix. Preferably, the helix has a longitudinal axis that runs parallel to the longitudinal direction of the helix. Preferably, the principal extension plane of the helix is ​​arranged at least substantially parallel to the principal extension plane of the wire mesh, at least in a planar laid-out and / or planar rolled-out state of the wire mesh, which may differ, in particular, from an installed state of the wire mesh. A "principal extension direction" of an object is understood, in particular, to be a direction that runs parallel to a longest edge of the smallest imaginary cuboid that just completely encloses the object.The term "at least substantially parallel" here refers in particular to an alignment of a direction relative to a reference direction, especially in a plane, wherein the direction has a deviation from the reference direction of particularly less than 8°, advantageously less than 5° and particularly advantageously less than 2°.

[0014] Preferably, the wire mesh comprises a plurality or a multiplicity of helixes, which are at least substantially identical in design, or in particular, identically designed. It is also conceivable that the wire mesh is formed from several different helixes. In particular, it is conceivable that the wire mesh comprises a plurality or multiplicity of first helixes and a plurality or multiplicity of second helixes that are designed differently from the first helixes and are arranged alternately. Advantageously, the helixes are connected to one another. In particular, adjacent helixes are arranged such that their longitudinal directions run parallel. Preferably, each helix is ​​woven and / or twisted into two adjacent helixes.In particular, the wire mesh can be produced by twisting a helix into the pre-mesh, twisting another helix into this twisted helix, twisting yet another helix into this further twisted helix, and so on. In particular, the helixes of the wire mesh have the same direction of twist. Advantageously, two helixes are knotted together, especially at one of their first ends and / or at a second end opposite the first ends.

[0015] Preferably, a torsional state of the longitudinal element, in particular the wire, in the helix corresponds to a torsional state of the longitudinal element, in particular the wire, before the longitudinal element, in particular the wire, is bent into the helix. In particular, the longitudinal element, in particular the wire, is twisted along a section of the helix, which comprises at least three bending points, advantageously at least four bending points, particularly advantageously at least five bending points, preferably at least ten bending points, particularly preferably at least fifteen bending points, and in a particularly preferable case at least twenty bending points, by less than one full turn in itself, in particular about its longitudinal axis.In particular, the longitudinal element along a section of the helix, which comprises a certain number of bends, is twisted by an angle that is smaller, advantageously at least twice as small, particularly advantageously at least three times as small, preferably at least five times as small, and particularly advantageously at least ten times as small as the sum of all bend angles of all bends of the section. Preferably, the longitudinal element, in particular the wire, exhibits a smaller torsion than a longitudinal element would exhibit in the case of bending at bends where the longitudinal element to be bent is held in such a way as to prevent rotation about its longitudinal axis.

[0016] In particular, the wire is at least partially, and especially, apart from any coating, entirely made of high-strength steel. For example, the high-strength steel may be spring steel and / or a steel suitable for wire ropes. In particular, the wire has a tensile strength of at least 800 N / mm², advantageously at least 1000 N / mm², particularly advantageously at least 1200 N / mm², preferably at least 1400 N / mm², and particularly preferably at least 1600 N / mm², and especially a tensile strength of approximately 1770 N / mm² or approximately 1960 N / mm². It is also conceivable that the wire has an even higher tensile strength, for example a tensile strength of at least 2000 N mm -2< , or of at least 2200 N mm -2< , or even of at least 2400 N mm -2< .. This can result in high load-bearing capacity, in particular high tensile strength and / or high stiffness perpendicular to the braid.

[0017] In an advantageous embodiment of the invention, it is proposed that the longitudinal element, in particular the wire, is bent along a section of the bending point in a manner that is at least substantially torsion-free or torsion-free. In particular, the longitudinal element, in particular the wire, is bent along a section of the helix in a manner that is at least substantially torsion-free or torsion-free. Advantageously, the helix is ​​torsion-free. Preferably, the wire mesh is woven from helixes that are bent in a torsion-free manner. This advantageously provides a load-bearing connection between adjacent helixes of a wire mesh. Furthermore, this prevents breaks in the area of ​​bending points.

[0018] In a particularly advantageous embodiment of the invention, it is proposed that a surface structure of the first leg and / or the second leg has a preferred direction extending parallel to a principal extension direction of the first leg and / or the second leg. Advantageously, the first leg and / or the second leg has at least one surface structure element extending parallel to the principal extension direction of the first leg and / or the second leg. For example, the surface structure element can be configured as a protrusion, particularly of less than 50 µm, advantageously of less than 20 µm, and particularly advantageously of less than 10 µm, and / or as a material region arranged on a wire surface, and / or as a surface microstructure. In particular, the surface structure comprises a plurality of surface structure elements.Advantageously, a majority of the surface structure elements run at least substantially parallel or parallel to the main direction of extension of the first leg and / or the second leg. In particular, the preferred direction corresponds to a mean direction of individual surface structure element orientations. The coating of the wire primarily forms the surface structure. However, it is also conceivable that the wire is free of a coating and forms the surface structure. This can result in high tensile strength.

[0019] Furthermore, it is proposed that the surface structure of the first leg and / or the second leg be free of substructures that are spirally and / or helically extending with respect to the main direction of extension of the first leg and / or the second leg, and in particular those that rotate and / or serpentine around the longitudinal direction of the helix. This advantageously prevents breakage or tearing of a wire mesh in a region of one leg.

[0020] Furthermore, it is proposed that, in a cross-sectional view parallel to a principal extension plane of the helix and perpendicular to a longitudinal direction of the helix, the bending point follows at least a section of an approximately straight path, in particular a straight path. In this context, "approximately straight" is understood to mean straight, preferably linear, especially within the limits of manufacturing tolerances. Preferably, in the cross-sectional view, a section of the bending point follows the approximately straight or straight path, comprising at least 50%, advantageously at least 75%, and particularly advantageously at least 85% of the bending point. Advantageously, in this section, and especially in a region of the bending point, the bending point is curved in a plane that is parallel to the approximately straight path of the bending point.Preferably, when viewed from the front, the approximately straight profile runs at least substantially parallel or parallel to the longitudinal direction of the helix. This allows for a bending point with high tensile strength and / or high bending stiffness. Furthermore, this provides a geometry that is advantageous for connecting bending points of different helixes.

[0021] Furthermore, it is proposed that, in a cross-sectional view, the helix follows a stepped, and in particular an inclined-stepped, profile at least in sections. Preferably, the first leg, the bend, and the second leg form the stepped profile in the cross-sectional view, wherein the bend, or at least its approximately straight section, forms an angle with the first leg and / or with the second leg that corresponds to the angle of inclination of the bend.

[0022] High stability of a wire mesh perpendicular to its surface can be achieved if the first leg and / or the second leg follow a straight line, at least in sections. Advantageously, the first leg and the second leg form straight sides of a mesh of the wire mesh. It is particularly advantageous if the entire first leg and / or the entire second leg is straight. In particular, the first leg and / or the second leg has a length of at least 1 cm, advantageously at least 2 cm, particularly advantageously at least 3 cm, preferably at least 5 cm, and most preferably at least 7 cm. However, the first leg and the second leg can have any other lengths, especially considerably longer ones.For example, the first leg and / or the second leg may have a length of at least 10 cm or at least 15 cm or at least 20 cm or at least 25 cm or an even greater length, particularly in the case that the helix is ​​formed from a strand of wire, a wire rope, a bundle of wire or the like.

[0023] In a further embodiment of the invention, it is proposed that the first leg extends at least partially in a first plane and the second leg extends at least partially in a second plane parallel to the first plane. In particular, at least two adjacent legs of the helix extend in parallel planes. Advantageously, the first leg extends parallel to the second leg in a transverse view. Preferably, the first leg and the second leg extend in the first plane and / or the second leg and the second leg extend in the second plane. Preferably, the first plane defines a front side of the wire mesh and / or the second plane a back side of the wire mesh, or vice versa. This allows a wire mesh with a double-surface and / or double-walled structure to be provided.Preferably, this allows forces acting perpendicular to the mesh to be absorbed effectively with minimal deformation of the mesh.

[0024] Furthermore, the invention relates to a method for producing a helix for a wire mesh, in particular for a safety net, in particular according to one of the preceding claims, wherein the helix is ​​bent from at least one single wire, a wire bundle, a wire strand, a wire rope and / or another longitudinal element with at least one wire, in particular having a high-strength steel, in such a way that it comprises at least one first leg, at least one second leg and at least one bending point connecting the first leg and the second leg.

[0025] It is proposed that the longitudinal element, in particular the wire, be bent along a course of the first leg and / or the second leg in a manner that is at least substantially free of torsion.

[0026] The inventive method enables the achievement of advantageous properties with regard to the load-bearing capacity of a wire mesh. Advantageously, a wire mesh with high tensile strength can be provided. Furthermore, breaks in the mesh, for example due to impacts from objects, can be reduced. Additionally, the strength of a wire used in production can be at least largely maintained. In particular, the tensile strength and / or brittleness and / or flexural stiffness and / or breaking strength of a wire used in production are only minimally or at least partially altered during manufacturing. Advantageously, wire breaks in the production of high-strength wire meshes can be avoided or at least reduced. Furthermore, manufacturing inaccuracies due to material stresses can be reduced.

[0027] Advantageously, the longitudinal element, in particular the wire, is bent by means of at least one bending device. The bending device particularly advantageously comprises at least one bending table. Preferably, the bending device comprises at least one bending mandrel around which the longitudinal element, in particular the wire, is bent, particularly by the bending table. Preferably, the wire is fed to the bending mandrel at an angle other than 90°, which in particular corresponds to a helix angle of the first leg relative to the longitudinal direction of the helix.

[0028] In particular, the process for manufacturing the wire mesh is provided. Advantageously, the process comprises at least one process step intended for the production and / or implementation of at least one of the features of the wire mesh. "Provided for" is understood to mean, in particular, specifically programmed, designed, and / or equipped. The fact that an object is intended for a specific function is understood to mean, in particular, that the object fulfills and / or performs this specific function in at least one application and / or operating state. The fact that a process is "intended for" a purpose is understood to mean, in particular, that the process includes at least one process step specifically aimed at the purpose, and / or that the process is specifically directed toward the purpose, and / or that the process serves to fulfill the purpose and is at least partially optimized for this fulfillment.

[0029] The fact that a procedural step is "intended" for a purpose should be understood in particular to mean that the procedural step specifically aims at the purpose and / or that the procedural step is specifically directed towards the purpose and / or that the procedural step serves to fulfill the purpose and is at least partially optimized towards this fulfillment.

[0030] Furthermore, it is proposed that the longitudinal element, in particular the wire, be fed to the bending device for bending, wherein the longitudinal element, in particular the wire, is rotated about its longitudinal axis during feeding. Preferably, one direction of rotation of the longitudinal element, in particular the wire, corresponds to a direction of rotation of the helix during feeding. In particular, the longitudinal element, in particular the wire, is rotated about its longitudinal axis in such a way that any torsion occurring during bending around the bending mandrel is compensated for. This advantageously prevents twisting of the wire during bending of a helix.

[0031] Furthermore, it is proposed that the longitudinal element, in particular the wire, passes through a rotating straightening device. Advantageously, the straightening device is rotated about the longitudinal axis of the longitudinal element, in particular the wire, especially at a rotational speed that corresponds, at least substantially, to the rotational speed of the longitudinal element, in particular the wire, about its longitudinal axis. Preferably, the straightening device is rotatably mounted about the longitudinal axis of the longitudinal element, in particular the wire. This advantageously allows for high manufacturing precision combined with high throughput.

[0032] In a preferred embodiment of the invention, it is proposed that the longitudinal element, in particular the wire, is unwound from a co-rotating reel. Advantageously, the reel is rotatably mounted about an unwinding axis. Particularly advantageous is the reel, and in particular a winding bearing of the reel, rotatably mounted about a rotational axis. In particular, the rotational axis of the reel is different from the unwinding axis of the reel. Preferably, the unwinding axis of the reel is perpendicular to the rotational axis of the reel. In particular, the unwinding axis is rotated about the rotational axis when the reel rotates. In particular, the rotation of the reel is synchronized with the rotation of the straightening apparatus. In particular, the reel is rotated about the rotational axis of the reel at a rotational speed that corresponds, in particular, at least substantially to a rotational speed of the longitudinal element, in particular the wire, about its longitudinal axis.In this context, "at least substantially" means, in particular, that a deviation from a predetermined value is less than 15%, preferably less than 10%, and most preferably less than 5% of the predetermined value. This advantageously allows for a long operating time between wire changes. Furthermore, it prevents wire twisting when fed to a bending device.

[0033] In a particularly preferred embodiment of the invention, it is proposed that torsion of the longitudinal element, particularly the wire, during bending by means of the bending device is compensated for by at least one adjustment of the rotational speed of the longitudinal element, particularly the wire. In particular, the rotational speed of the longitudinal element, particularly the wire, corresponds at least substantially to a torsional speed of the longitudinal element, particularly the wire, caused by the bending. This advantageously enables the fast and precise production of torsion-free coils for a wire mesh.

[0034] It is further proposed that the longitudinal element, in particular the wire, be rotated at least by a compensation angle for bending the bending point. This compensation angle corresponds to an angle between the first leg and the second leg in a frontal view perpendicular to a principal extension plane of the helix, in particular an angle between a longitudinal axis of the first leg and a longitudinal axis of the second leg. Specifically, the longitudinal element, in particular the wire, is rotated by the compensation angle for each bent bending point. Advantageously, the angular velocity of the rotation of the longitudinal element, in particular the wire, corresponds to the angle between the first leg and the second leg in the frontal view multiplied by a production rate of bending points. This allows the compensation rotation of a longitudinal element to be advantageously adapted to the geometry of a helix to be bent.

[0035] Advantageous properties with regard to precise and / or rapid production of a durable wire mesh can be achieved with a manufacturing device for producing a wire mesh, which is designed to carry out the method according to the invention.

[0036] A wire mesh, a bending device, and a method according to the invention are not limited to the applications and embodiments described above. In particular, a wire mesh, a bending device, and a method according to the invention may, for achieving a functionality described herein, comprise a different number of individual elements, components, units, and / or process steps than that specified herein. Drawings

[0037] Further advantages become apparent from the following description of the drawings. The drawings illustrate two exemplary embodiments of the invention. The drawings, the description, and the claims contain numerous features in combination. A person skilled in the art will expediently consider the features individually and combine them into meaningful further combinations.

[0038] They show: Fig. 1 a part of a wire mesh in a schematic front view, Fig. 2 a part of a helix of the wire mesh in a perspective view, Fig. 3 another part of the wire mesh in a schematic front view, Fig. 4 two legs and a bending point of the helix in different views, Fig. 5 two connected bending points of two helixes in different views, Fig. 6 a part of the helix in a longitudinal view, in a schematic view, Fig. 7 a part of the helix in a transverse view, in a schematic view, Fig. 8 a part of the helix in a perspective view, Fig. 9 a schematic flowchart of a process for manufacturing the wire mesh, Fig. 10 a manufacturing device for manufacturing the wire mesh in a schematic view, Fig. 11 a bending device of the manufacturing device in a perspective view, Fig.Fig. 12 shows a bending chamber of the bending device in a first operating state in a perspective view, Fig. 13 shows the bending chamber in a second operating state in a perspective view, Fig. 14 shows a part of another wire mesh in a schematic front view, and Fig. 15 shows a part of the other wire mesh in a longitudinal view, in a schematic representation. Description of the exemplary implementations

[0039] The Figure 1Figure 1 shows a schematic front view of a portion of a wire mesh 10a. The wire mesh 10a is designed as a safety net. The wire mesh 10a shown can be used, for example, as slope stabilization, an avalanche protection net, a safety fence, or the like. The wire mesh 10a has several interwoven helixes 12a, 14a, in particular one helix 12a and another helix 14a. In this case, the wire mesh 10a has a plurality of identically designed helixes 12a, 14a that are twisted together and form the wire mesh 10a.

[0040] The Figure 2 shows a part of the helix 12a of the wire mesh 10a in a perspective view. Figure 3Figure 1 shows another part of the wire mesh 10a in a schematic front view. The helix 12a is made from a longitudinal element 16a. The longitudinal element 16a has a wire 18a. In this case, the longitudinal element 16a is the wire 18a. However, it is also conceivable that a longitudinal element comprises a plurality of wires and / or other elements. For example, a longitudinal element can be designed as a wire rope, a wire bundle, a strand of wire, or the like. The properties of the wire 18a are described below. These are, however, transferable to the case of other longitudinal elements. Analogously to the wire 18a shown, for example, a strand of wire, a wire bundle, or another longitudinal element can be bent into a helix, and helixes made of such longitudinal elements can be connected to form a wire mesh.

[0041] In the present case, wire 18a is designed as a single wire. Wire 18a has a corrosion-resistant coating. Wire 18a is bent into the helix 12a. The helix 12a is formed in one piece. The helix 12a is made from a single piece of wire. In the present case, wire 18a has a diameter of 3 mm. Wire 18a is made at least partially of high-strength steel. Wire 18a is designed as a high-strength steel wire. Wire 18a has a tensile strength of at least 800 N / mm². In the present case, wire 18a has a tensile strength of approximately 1770 N / mm². Of course, as mentioned above, other tensile strengths are also conceivable, in particular tensile strengths of more than 2200 N / mm². In particular, it is conceivable that a wire is made of ultra-high-strength steel.It is also conceivable that a wire has a different diameter, such as less than 1 mm, or approximately 1 mm, or approximately 2 mm, or approximately 4 mm, or approximately 5 mm, or approximately 6 mm, or an even larger diameter. As mentioned above, it is conceivable that a wire consists of different materials and, in particular, is designed as a composite wire.

[0042] The helix 12a and the subsequent helix 14a are identical in design. Therefore, helix 12a is described in more detail below as an example. However, it is conceivable that a wire mesh comprises at least one first helix and at least one second helix with a different design.

[0043] The helix 12a has a first leg 20a, a second leg 22a, and a bend 24a connecting the first leg 20a and the second leg 22a. In this case, the helix 12a has a plurality of first legs 20a, a plurality of second legs 22a, and a plurality of bends 24a, not all of which are labelled for clarity. Furthermore, in this case, the first legs 20a are at least substantially identical to each other. Additionally, in this case, the second legs 22a are at least substantially identical to each other. Moreover, in this case, the bends 24a are at least substantially identical to each other. Therefore, the first leg 20a, the second leg 22a, and the bend 24a are described in more detail below as examples.It is of course conceivable that a wire mesh has different first legs and / or different second legs and / or different bending points.

[0044] The helix 12a has a longitudinal direction 28a. The helix 12a has a longitudinal axis 109a, which runs parallel to the longitudinal direction 28a. The longitudinal direction 28a corresponds to a principal extension direction of the helix 12a. In a frontal view perpendicular to a principal extension plane of the helix 12a, the first leg 20a runs with a first inclination angle 26a with respect to the longitudinal direction 28a of the helix 12a. In particular, the frontal view is a view in the frontal direction 54a. The first leg 20a has a longitudinal axis 110a. The longitudinal axis 110a of the first leg 20a runs parallel to a principal extension direction 112a of the first leg 20a. In the Figure 3The helix 12a is shown in a frontal view. The longitudinal axis 109a of the helix 12a and the longitudinal axis 110a of the first leg 20a enclose the first angle of inclination 26a. In this case, the first leg 20a has a length of approximately 65 mm. The second leg 22a also has a length of approximately 65 mm.

[0045] The Figure 4 shows a part of the helix 12a, which includes the first leg 20a, the second leg 22a and the bending point 24a, in different views. Figure 4a shows a view in the longitudinal direction 28a of the helix 12a. Figure 4b shows the first leg 20a, the second leg 22a and the bending point 24a in a transverse view perpendicular to the longitudinal direction 28a of the helix 12a and in the main extension plane of the helix 12a. Figure 4c A view in the frontal direction is shown in 54a. Figure 4dThis shows a perspective view. In the cross-sectional view, the bend 24a runs, at least in sections, with a second inclination angle 30a, different from the first inclination angle 26a, with respect to the longitudinal direction 28a of the helix 12a. In the cross-sectional view, the bend 24a has a longitudinal axis 114a. The longitudinal axis 114a of the bend 24a and the longitudinal axis 109a of the helix 12a enclose the second inclination angle 30a.

[0046] The second slope angle 30a differs from the first slope angle 26a by at least 5°. The second slope angle 30a has a value between 25° and 65°. Furthermore, the first slope angle 26a is greater than 45°.

[0047] In this case, the first inclination angle 26a is approximately 60°. Furthermore, in this case, the second inclination angle 30a is approximately 45°. The second inclination angle 30a is smaller than the first inclination angle 26a.

[0048] It is of course also conceivable that the first and second helix angles are identical. For example, both the first and second helix angles could be at least substantially or exactly 45°. Other values ​​are also conceivable, such as 30°, 35°, 40°, 50°, 55°, 60°, 65°, 70°, or other, particularly larger or smaller, values. A person skilled in the art will select suitable values ​​for the first and second helix angles, particularly depending on the requirements profile for the corresponding wire mesh.

[0049] In cross-sectional analysis, bend 24a follows at least an approximately straight line in some sections. In the present case, a large part of bend 24a follows a straight line in cross-sectional analysis.

[0050] Viewed from the side, spiral ramp 12a follows a stepped profile, at least in sections. This stepped profile is obliquely stepped.

[0051] The first leg 20a follows a straight path, at least in sections. In the present case, the first leg 20a follows a straight path. The second leg 22a follows a straight path, at least in sections. In the present case, the second leg 22a follows a straight path. The first leg 20a and / or the second leg 22a are free of any curvature, bending, and / or kink. The bend 24a comprises a path which, viewed longitudinally parallel to the longitudinal direction 28a of the helix 12a, describes a bend of 180°. In the Figure 4a The helix 12a is shown in longitudinal view.

[0052] The first leg 20a runs at least partially, and in particular completely, in a first plane, and the second leg 22a runs at least partially, and in particular completely, in a second plane parallel to the first plane. Viewed longitudinally, the first leg 20a runs parallel to the second leg 22a.

[0053] The further helix 14a has a further bend 32a. Bend 24a and the further bend 32a are connected. Bend 24a and the further bend 32a form a connection point between helix 12a and the further helix 14a.

[0054] The Figure 5 shows a part of the wire mesh 10a, which includes the bending point 24a and the further bending point 32a, in different views. Figure 5a shows a view in the longitudinal direction 28a of the helix 12a. Figure 5bshows the part of the wire mesh 10a in a cross-sectional view perpendicular to the longitudinal direction 28a of the helix 12a in the main extension plane of the helix 12a. Figure 5c A view in the frontal direction is shown in 54a. Figure 5d shows a perspective view.

[0055] The helix 12a and the subsequent helix 14a intersect at least substantially perpendicularly in a region of the further bend 32a. Viewed from the side, the bend 24a and the subsequent bend 32a form an intersection angle 118a. The intersection angle 118a depends on the second pitch angle 30a and a correspondingly defined further pitch angle of the subsequent helix 14a. In this case, the intersection angle 118a is 90°.

[0056] For other initial helix angles, a second helix angle of 45° is also advantageously chosen, so that appropriately designed helixes cross perpendicularly at connection points, and these connection points advantageously exhibit high mechanical strength. Of course, however, crossing angles other than 90° are also conceivable, for example, with a value of 45°, 60°, 120°, 145°, or a larger, smaller, or intermediate value. A person skilled in the art will select a suitable crossing angle, particularly depending on the requirements profile for the corresponding wire mesh.

[0057] The Figure 6 shows a section of helix 12a in a longitudinal view, in a schematic representation. Figure 7 shows a section of helix 12a in a longitudinal view, in a schematic representation. Figure 8Figure 1 shows a portion of the helix 12a in a perspective view. The wire 18a is bent along the first leg 20a and the second leg 22a, at least substantially free of torsion. Furthermore, the wire 18a is bent along the bend 24a, at least substantially free of torsion.

[0058] The first leg 22a is free of torsion. In particular, the first leg 22a is not twisted. The second leg 22a is free of torsion. In particular, the second leg 22a is not twisted. The bend 24a is free of torsion along its length. In the cross-sectional view (cf. Fig. 7 The bend 24a is torsion-free. It is conceivable that a helix has torsion-free legs but at least a slightly twisted bend.

[0059] The first leg 20a has a surface structure 200a which has a preferred direction 202a that extends parallel to the main extension direction 112a of the first leg 20a. The surface structure 200a of the first leg 20a is free of substructures that extend spirally or helically with respect to the main extension direction 112a of the first leg 20a.

[0060] The surface structure 200a extends over the bend 24a. The surface structure 200a extends over the second leg 20a. The surface structure 200a has a preferred direction 203a, which extends parallel to a main extension direction 220a of the second leg 22a. The surface structure 200a of the second leg 22a is free of spirally or helically extending substructures.

[0061] The surface structure 200a comprises a multitude of surface structure elements 214a, 216a, 218a, not all of which are labelled for clarity. The surface structure elements 214a, 216a, 218a are formed as protrusions on a surface of the wire 18a, in particular as protrusions in the micrometer range. The surface structure elements 214a, 216a, 218a are part of a surface microstructure of the wire 18a. The surface structure elements 214a, 216a, 218a have at least substantially straight lines along the first leg 20a. Furthermore, the surface structure elements 214a, 216a, 218a extend parallel to the course of the bend 24a in a region of the bend 24a. Furthermore, the surface structure elements 214a, 216a, 218a exhibit at least essentially straight profiles along the second leg 22a.Surface structure elements 214a, 216a, and 218a each run in a plane along the first leg 20a. Surface structure elements 214a, 216a, and 218a each run in a plane along the second leg 22a. Surface structure elements 214a, 216a, and 218a each run in a plane along the bend 24a. On average, surface structure elements 214a, 216a, and 218a run along the preferred direction 202a, 203a of surface structure 200a. The preferred direction 202a, 203a of surface structure 200a follows the course of the helix 12a.

[0062] The Figure 9Figure 224a shows a schematic flowchart of a process for manufacturing the wire mesh 10a. In a first process step 224a, the helix 12a is manufactured from the wire 18a such that the wire 18a is bent along the path of the first leg 20a and the second leg 22a, at least substantially free of torsion. In a second process step 226a, the helix 12a is woven into a pre-weave of the wire mesh 10a.

[0063] The Figure 10Figure 222a shows a manufacturing device 222a for producing the wire mesh 10a. The manufacturing device 222a is designed to produce the wire mesh 10a. The manufacturing device 222a includes a bending device 74a. The longitudinal element 16a, or in this case its wire 18a, is bent by means of the bending device 74a, to which the wire 18a is fed for bending, whereby the wire 18a is rotated about its longitudinal axis 204a during feeding. For a description of the bending device 74a, reference is made to the Figures 11 to 13 Reference is made to the following. If, instead of wire 18a, a longitudinal element not designed as a single wire, such as a strand and / or a wire bundle or the like, is used, it is processed and / or guided and / or bent and / or straightened, etc., analogously to wire 18a. However, the following describes the case where the longitudinal element 16a is designed as wire 18a.

[0064] The manufacturing device 222a has a rotating straightening apparatus 206a. During the production of the helix 12a, the wire 18a passes through the rotating straightening apparatus 206a. The straightening apparatus 206a is rotatably mounted about a rotational axis 228a. The rotational axis 228a corresponds to the longitudinal axis 204a of the wire 18a.

[0065] The manufacturing device 222a has a co-rotating reel 208a. During the production of the helix 12a, the wire 18a is unwound from the co-rotating reel 208a. The co-rotating reel 208a is rotatably mounted about the axis of rotation 228a. To unwind the wire 18a from the co-rotating reel 208a, the co-rotating reel 208a is rotated about an unwinding axis 230a, which is arranged perpendicular to the axis of rotation 228a. When the co-rotating reel 208a rotates about the axis of rotation 228a, the unwinding axis 230a also rotates about the axis of rotation 228a.

[0066] The manufacturing device 222a has a drive unit (not shown) that is designed to rotate the co-rotating reel 208a and the straightening device 206a, and thus the wire 18a, about the axis of rotation 228a. In the case shown, the straightening device 206a and the reel 208a rotate about the same axis of rotation 228a. It is also conceivable, of course, that the wire 18a is guided around at least one curve between the co-rotating reel 208a and the straightening device 206a, and that the straightening device 206a is rotated about a different axis of rotation than the reel 208a. In this case, the longitudinal axis 204a of the wire 18a runs differently in one region of the reel 208a than in one region of the straightening device 206a.

[0067] Torsion of the wire 18a during bending using the bending device 74a is compensated for by adjusting the rotational speed of the wire 18a.

[0068] The wire 18a is rotated at least by a compensating angle for bending at the bending point 24a. This compensating angle corresponds to an angle 212a between the first leg 22a and the second leg 22a when viewed from the front and perpendicular to a principal plane of extension of the helix 12a. In particular, the first helix angle 26a and half of the angle 212a between the first leg 20a and the second leg 22a add up to 90°. When the wire 18a is bent using the bending device 74a, a torsion of the wire 18a by the amount of the angle 212a between the first leg 20a and the second leg 22a is generated at each bent bending point. This generated torsion is compensated by rotating the wire 18a about its longitudinal axis 204a. The wire 18a is rotated in a direction that corresponds to a direction of rotation of the helix 12a.

[0069] The Figure 11Figure 1 shows the bending device 74a of the manufacturing device 222a in a perspective view. Figure 12 Figure 1 shows a bending chamber 140a of the bending device 74a in a first operating state in a perspective view. Figure 13 Figure 1 shows the bending chamber 140a in a second operating state in a perspective view. The bending device 74a is designed to produce the first helix 12a. The bending device 74a is designed to bend the first helix 12a according to the geometry of the first helix 12a, in particular the legs 20a, 22a and the bending point 24a of the first helix 12a. The bending device 74a is designed to produce the first helix 12a from the wire 18a. In its unstewed state, the wire 18a forms a helix blank 76a. The bending device 74a is designed to produce the first helix 12a by bending the helix blank 76a.

[0070] The bending device 74a has a bending unit 78a. The bending unit 78a comprises a bending mandrel 80a and a bending table 82a. The bending table 82a is designed for bending the helical blank 76a around the bending mandrel 80a. The bending table 82a is fully supported around the bending mandrel 80a. During production, the bending table 82a rotates continuously in a direction 142a around the bending mandrel 80a. The bending mandrel 80a has a longitudinal axis 144a. The longitudinal axis 144a of the bending mandrel 80a runs parallel to a principal extension direction 94a of the bending mandrel 80a.

[0071] The bending device 74a has a feed unit 84a, which is designed to advance the helical blank 76a along a feed axis 86a in a feed direction 88a. The feed axis 86a is arranged parallel to the feed direction 88a. The feed direction 88a runs parallel to a principal extension direction of the helical blank 76a. The feed axis 86a forms an angle with the longitudinal axis 144a of the bending mandrel 80a, which corresponds at least substantially and in particular exactly to the first helix angle 26a. The first helix angle 26a can be set by adjusting the feed axis 86a relative to the longitudinal axis 144a of the bending mandrel 80a.

[0072] During production, the spiral blank 76a is repeatedly advanced. After each advance, the bending unit 78a, in particular the bending table 82a, bends the spiral blank 76a around the bending mandrel 80a to create a bend in the first spiral 12a produced. During bending, the feed unit 84a releases the spiral blank 76a, allowing it to rotate around the longitudinal axis 204a of the wire 18a due to the rotation of the wire 18a. It is conceivable that the wire 18a is guided around at least one curve and that its longitudinal axis 204a differs from the axis of rotation 228a of the co-rotating reel 208a and / or the straightening device 206a in a region of the feed unit 84a and / or in a region of the bending chamber 140a. The diameter of the bending mandrel 80a defines a bending curvature of the bending point 24a. In particular, the diameter of the bending mandrel 80a defines an inner radius of the bending point 24a.

[0073] The bending device 74a has a stop unit 96a with at least one stop element 98a, which defines a maximum feed position for the helical blank 76a. During feeding, the helical blank 76a can be advanced by the feed unit 84a up to the maximum feed position. Before bending by the bending table 82a around the bending mandrel 80a, the helical blank 76a is in the maximum feed position. In the maximum feed position, the helical blank 76a, with a last bent bend point 166a of the first helix 12a, abuts the stop element 98a. The Figure 12 The first operating state shown corresponds to a situation immediately before the helical blank 76a is bent around the bending mandrel 80a. In this first operating state, the helical blank 76a is in the maximum feed position. The Figure 13The second operating state shown corresponds to a situation during the bending of the helical blank 76a around the bending mandrel 80a. In the second operating state, the bending table 82a is displaced along the direction of rotation 142a compared to its position in the first operating state.

[0074] The stop element 98a is fully supported around the bending mandrel 80a. During manufacturing, the stop element 98a rotates continuously around the bending mandrel 80a in the direction of rotation 142a.

[0075] The bending table 82a is pivotally mounted about a pivot axis 102a, which, as the bending table 82a rotates around the bending mandrel 80a, also rotates around the mandrel 80a, particularly in the direction of rotation 142a. During production, the pivot axis 102a moves along a circular path. The pivot axis 102a moves at a constant angular velocity during production. During bending, the bending table 82a and the stop element 98a rotate around the bending mandrel 80a at the same speed. After bending, the bending table 82a pivots out about the pivot axis 102a, thus defining a maximum bending angle. The bending table 82a then pivots back about the pivot axis 102a, particularly during the advancement of the spiral blank 76a. In the initial operating state, the stop element 98a rests on the bending table 82a.

[0076] In this case, the bending mandrel 80a is driven. The bending mandrel 80a is rotatably mounted about its longitudinal axis 144a. The bending mandrel 80a is coupled via a belt 164a to a drive unit (not shown), which in particular also drives the bending table 82a. The bending mandrel 80a is designed to be interchangeable. The bending unit 78a can be fitted with bending mandrels of different diameters.

[0077] The position of the bending table 82a relative to the stop element 98a changes when the bending table 82a rotates around the bending mandrel 80a.

[0078] The stop element 98a has a concavely curved stop surface 100a. The stop surface 100a is curved in a circular arc in the direction of rotation 142a. Furthermore, the stop surface 100a is curved in a circular arc perpendicular to the curvature in the direction of rotation 142a. A radius of this curvature perpendicular to the direction of rotation 142a corresponds at least substantially to a curvature of the bending point 24a. In the maximum feed position, the last bent bending point 166a rests against the stop surface 100a, which curves in a circular arc around the last bent bending point 166a.

[0079] In a feed operating state, in which the helical blank 76a is being fed, the position of the stop element 98a relative to the feed axis 86a is variable. In this feed operating state, particularly after the helical blank 76a is in contact with the stop element 98a, and thus is in its maximum feed position, the stop element 98a moves along the last bent bending point 166a in the direction of rotation 142a.

[0080] The bending unit 78a is designed for bending a helical blank with at least one wire made of high-strength steel. In this case, the helical blank 76a can be bent using the bending unit 78a.

[0081] The bending unit 78a is designed to bend the helical blank 76a by more than 180° during a single revolution, and in particular during each revolution, of the bending table 82a around the bending mandrel 80a. A bending angle is defined by the point in time at which the bending table 82a pivots about the pivot axis 102a. The bending unit 78a is designed to overbend the helical blank 76a, in particular to compensate for springback of the helical blank 76a after bending due to its high bending stiffness. The bending unit 78a is designed to provide the bending point 24a with a total angle of exactly 180°, so that the first helix 12a can be manufactured with a straight path.

[0082] In the Figures 14 and 15A further embodiment of the invention is shown. The following descriptions and drawings are essentially limited to the differences between the embodiments, whereby with regard to identically designated components, in particular components with the same reference numerals, reference is also generally made to the drawings and / or the description of the other embodiment, in particular the Figures 1 to 13 , can be referenced. To distinguish the embodiments, the letter a is the reference numeral of the embodiment in the Figures 1 to 13 recreated. In the exemplary embodiment of the Figures 14 and 15 The letter a is replaced by the letter b.

[0083] The Figure 14Figure 1 shows a portion of a wire mesh 10b with several interwoven helixes 12b, at least one of which is bent from at least one longitudinal element 16b and comprises at least a first leg 20b, a second leg 22b, and at least one bend 24b connecting the first leg 20b and the second leg 22b. The longitudinal element 16b is bent along the course of the first leg 20b and the second leg 22b in a manner that is at least substantially free of torsion. In particular, a torsional state of the longitudinal element 16b in the wire mesh 12b corresponds to a torsional state of a blank of the longitudinal element 16b before its processing into the wire mesh 12b. In the present case, the longitudinal element 16b is designed as a wire strand. The longitudinal element 16b comprises at least one wire 18b made of a high-strength steel.In the present case, the longitudinal element 16b is made of a plurality of identical wires 18b, which are not shown individually in the figures. In a frontal view perpendicular to a principal plane of extension of the helix 12b, the first leg 20b runs with a first angle of inclination 26b with respect to the longitudinal direction 28b of the helix 12b. In the present case, the first angle of inclination 26b is approximately 45°. The wire mesh 10b has square meshes in the present case.

[0084] The Figure 15 shows a part of the wire mesh 10b in a longitudinal view along a longitudinal direction 28b of the helix 12b (cf. Fig. 14 The first leg 20b and the second leg 22b have a curved shape. The wire mesh 10b has convex meshes, which can dampen impacts, in particular, from objects striking it perpendicular to the wire mesh 10b.

[0085] The helix 12b is produced using a conventional braiding machine (not shown) with a braiding knife. During the production of the helix 12b, the longitudinal element 16b is rotated about its longitudinal axis to compensate for torsion occurring when the longitudinal element 16b is bent by the braiding knife. Reference sign

[0086] 10 Wire mesh 12 Helix 14 Helix 16 Longitudinal element 18 Wire 20 Leg 22 Leg 24 Bending point 26 Pitch angle 28 Longitudinal direction 30 Pitch angle 32 Bending point 54 Frontal direction 74 Bending device 76 Helix blank 78 Bending unit 80 Bending mandrel 82 Bending table 84 Feed unit 86 Feed axis 88 Feed direction 94 Main extension direction 96 Stop unit 98 Stop element 100 Stop surface 102 Swivel axis 109 Longitudinal axis 110 Longitudinal axis 112 Main extension direction 114 Longitudinal axis 118 Crossover angle 140 Bending space 142 Circulation direction 144 Longitudinal axis 164 Belt 166 Bending point 200 Surface structure 202 Preferred direction 203 Preferred direction 204 Longitudinal axis 206 Straightening device 208 Reel 212 Angle 214 Surface structure element 216 Surface structure element 218 Surface structure element 220 Main extension direction 222 Manufacturing device 224 Process step 226 Process step 228 Rotation axis 230 Unrolling axis

Claims

1. Wire netting (10a; 10b), in particular a safety net, with a plurality of helices (12a, 14a; 12b) which are braided with each other, of which at least one helix (12a, 14a; 12b) is bent from at least one single wire, a wire bundle, a wire strand, a wire rope and / or another longitudinal element (16a; 16b) with at least one wire (18a; 18b), which in particular comprises a high-tensile steel, the at least one helix (12a, 14a; 12b) having at least one first leg (20a; 20b), at least one second leg (22a; 22b) as well as at least one bending region (24a; 24b) connecting the first leg (20a; 20b) and the second leg (22a; 22b) to each other, characterised in that the longitudinal element (16a; 16b) is bent at least substantially torsion-free in itself along a contour of the first leg (20a; 20b) and / or of the second leg (22a; 22b).

2. Wire netting (10a; 10b) according to claim 1, characterised in that the longitudinal element (16a; 16b) is bent, at least substantially without any torsion in itself, along a contour of the bending region (24a; 24b).

3. Wire netting (10a) according to claim 1 or 2, characterised in that a surface structure (200a) of the first leg (20a) and / or of the second leg (22a) has a preferential direction (202a) which extends parallel to a main extension direction (112a) of the first leg (20a) and / or of the second leg (22a).

4. Wire netting (10a) according to claim 3, characterised in that the surface structure (200a) of the first leg (20a) and / or of the second leg (22a) is free from partial structures extending spirally with respect to the main extension direction (112a) of the first leg (20a) and / or of the second leg (22a).

5. Wire netting (10a) according to one of the preceding claims, characterised in that, in a transverse view parallel to a main extension plane of the helix (12a) and perpendicularly to a longitudinal direction (28a) of the helix (12a), the bending region (24a) at least section-wise follows an at least approximately straight course.

6. Wire netting (10a) according to claim 5, characterised in that, in the transverse view, the helix (12a) follows at least section-wise a stepped contour.

7. Wire netting (10a) according to one of the preceding claims, characterised in that the first leg (20a) and / or the second leg (22a) at least section-wise follow / follows a straight contour.

8. Wire netting (10a) according to one of the preceding claims, characterised in that the first leg (20a) runs at least section-wise in a first plane and the second leg (22a) extends at least section-wise in a second plane that is parallel to the first plane.

9. Wire netting (10a; 10b) according to one of the preceding claims, characterised in that the wire (18a; 18b) comprises a high-tensile steel and / or has a tensile strength of at least 800 N mm-2.

10. Method for manufacturing a helix (12a) for a wire netting (10a), in particular for a safety net, in particular according to any one of the preceding claims, wherein the helix (12a) is bent from at least one single wire, a wire bundle, a wire strand, a wire rope and / or another longitudinal element (16a; 16b) with at least one wire (18a; 18b), which in particular comprises a high-tensile steel, in such a way that it comprises at least one first leg (20a), at least one second leg (22a) as well as at least one bending region (24a) connecting the first leg (20a) and the second leg (22a) to each other, characterised in that the longitudinal element (16a; 16b) is bent, at least substantially without any torsion in itself, along a contour of the first leg (20a) and / or of the second leg (22a), wherein the longitudinal element (16a) is bent by means of a bending device (74a), which the longitudinal element (16a) is supplied to for bending, and wherein during conveyance the longitudinal element (16a) is rotated about its longitudinal axis (204a).

11. Method according to claim 10, characterised in that the longitudinal element (16a) passes through a rotating orienting apparatus (206a).

12. Method according to claim 10 or 11, characterised in that the longitudinal element (16a) is unwound from a co-rotated reel (208a).

13. Method according to one of claims 10 to 12, characterised in that, by at least one adjustment of a rotation speed of the longitudinal element (16a), a torsion of the longitudinal element (16a) is compensated by the bending device (74a) during a bending.

14. Method according to claim 13, characterised in that, for a bending of the bending region (24a), the longitudinal element (16a) is rotated at least by a compensating angle, which corresponds to an angle (212a) between the first leg (20a) and the second leg (22a) in a front view perpendicular to a main extension plane of the helix (12a).