Welded netting with deformed stretching wires and method of making such netting

Abstract: This invention relates to a sheet-shaped welded netting of metal at least comprising mesh-forming wires extending longitudinally of the sheet and/or mesh-forming wires extending transversely of the sheet as well as several deformed stretching wires extending longitudinally of the sheet which can stretch under tensile stress and which may or may not have the function of mesh-forming wires extending longitudinally of the sheet, the deformations in the stretching wires substantially lying in the plane of the netting and the stretching wires displaying a regular arrangement of identical patterns longitudinally of the sheet, whereby the deformation of the stretching wires is such that the ratio of the maximum dimension (B) of a mesh longitudinally of the sheet to the distance (A) between two consecutive maxima in a deformed stretching wire is at least about three, that the maxima of two adjacent stretching wires of the welded netting may or may not have the same position with respect to the longitudinal direction of the netting and that the arrangement of identical patterns of each of the stretching wires is randomly positioned with respect to the arrangement of the meshes in the welded netting.

Description: The invention relates to a type of welded mesh, adapted for fencing purposes, comprising a first group of wires, extending in a longitudinal and/or transverse direction of the mesh and forming together a pattern having a periodicity in the longitudinal direction by which a number of consecutive pattern-cycles can be distinguished, and further comprising a second group of wires, extending in the longitudinal direction, each showing incurvations in the plane of the mesh, showing consecutive maxima and according to a pattern with a periodicity in the longitudinal direction, by which a number of consecutive incurvation-cycles can be distinguished, the longitudinally measured length of the wires being at least 90 % of the length, measured along the wire, said first and second group of wires forming together a configuration of wire meshes, showing a maximum mesh dimension (B) in the longitudinal direction. Such welded mesh in known from French Patent Application N° 2.584.957 and US Patent N° 3,503,590. These publications describe a welded wire mesh for fencing purposes wherein longitudinally running stretching wires are present that are deformed so as to have an apparent length of at least 90 % of their actual length, so as to be able on one hand to stretch the welded mesh taut and on the other hand to make the welded mesh resistant to deformation under forces that are normally expectable when used in a fence. These are the wires of the second group as referred to hereinabove, which, because of their stretching function, are also called "stretching wires" hereinafter. A welded wire mesh structure is also known from US Patent N° 4,074,731, although for antenna reflector purposes, having stretching wires running in one direction, having undulations so as to be able to stretch the wire mesh taut for avoiding any slack that would bring the mesh outside a desired reflection plane. These wires are deformed, with an apparent length of much less than 90 % of the actual length, in order to have a desired low spring rate. Although they can serve to hold the wire mesh taut, the low apparent length and low spring rate do not allow to use such wire mesh for fencing purposes. In the abovementioned publications about welded wire mesh for fencing purposes, the incurvation pattern of the stretching wires has the same periodicity and is in phase with the pattern of the wires of the first group. A welded wire mesh with such stretching wires can be made either by using undeformed stretching wires when welding the wire mesh together and deforming those stretching wires after welding, or by using stretching wires that have already been deformed before welding the wire mesh together. This second method has the advantage that there is no damage danger for the welds during deformation, but has the disadvantage that the stretching wires have to be positioned very accurately with respect to the wires of the first group, in order to avoid unaesthetic out-of-phase effects. Such second method, if feasible at all, is extremely difficult and costly. The first method however is not simple either, because the welded mesh at the exit of the welding machine needs accurate positioning of the welded mesh before receiving the incurvations, which positioning is not necessary for incurvations on a single wire at the entrance of the welding machine as in the second method. For such known welded mesh, a choice has to be made between both methods. It is the object of the present invention to provide a welded wire mesh, adapted for fencing purposes, in which the aforesaid positioning problems of the stretching wires no longer occurs, and which nevertheless allows to start from stretching wires of a type deformed beforehand. To that end, the welded mesh of the initially described type is characterised, in accordance with the invention, in that the ratio of said maximum mesh dimensions (B), as obtained in said mesh configuration as formed by said first and second group of wires, to the distance (A), between two consecutive maxima of the incurvations of the wires of the second group, is at least three and that consecutive incurvation-cycles of the second wire group are located at random with respect to the consecutive pattern-cycles of the first wire group. Indeed, it has been found that if the period of the deformations in a stretching wire is made sufficiently small, an out-of-phase course of the stretching wire and the mesh pattern of the first group of wires is no longer felt to be awkward. An out-of-phase course of the stretching wires and the pattern of the first group of wires in the prior-art welded mesh described hereinbefore is generally very awkward and major efforts are therefore being made to guarantee phase coincidence of the stretching wires and the said pattern. Welded mesh of the type as described hereinbefore, for being adapted for fencing purposes, has a good tensionability, a good resistance to deformation and a uniform aspect. In the following description, the deformation criterion used will always be the distance (A) between two consecutive maxima in a deformed stretching wire. In this case, a maximum is understood to mean the location of maximum deviation of the deformed stretching wire with respect to the neutral line of said stretching wire; the maxima may be located on one side of said central line as well as on either side. If the deformation of a stretching wire were sine shaped, the distance between two maxima would as a consequence equal half a period of the sine function. In the aforesaid characteristic, the ratio of the maximum mesh dimension (B) in the longitudinal direction of the welded mesh to the distance (A) between two consecutive maxima is deliberately defined as at least about 3. The meaning of this is that when applying such a degree of deformation, the exact ratio between the said dimensions becomes less important as, essentially, each stretching wire can be applied longitudinally of the netting in an arbitrary way irrespective of the periodicity of the pattern of the first wire group itself. Consequently, a value of said ratio equalling 2.9 will give as good results as a ratio of 3.0 or 3.1. In particular, however, a ratio will be chosen that comes to at least about 5. As regards the amplitude of the patterns of each stretching wire in the plane of the welded netting sheet, each pattern of a stretching wire is such that the deviation at a maximum with respect to the central line of this stretching wire is not more than 10 % of the maximum mesh dimension (C) of a mesh of the welded netting transversal direction of the welded mesh. The deformation of each stretching wire is such that the length of a unit part of it longitudinally of the welded mesh comes to at least 90 % of the length of said unit part in undeformed condition. Advantageously, the distance between two adjacent stretching wires in the welded mesh comes to less than 250 mm. Very advantageously, in the welded mesh in accordance with the present invention at least two stretching wires are present in the longitudinal edge area of the welded mesh at distance from each other that is smaller than half the maximum mesh dimension transversely of the sheet. An arrangement of such stretching wires extending relatively close to one another in the peripheral area of the netting gives the netting an extremely good tensionability and a great stability. As indicated hereinbefore, a precise positioning of the different stretching wires with respect to one another as well as a symmetrical placing of each of the stretching wires with respect to the pattern of the first wire group are no longer necessary because of the short distance between the maxima of the stretching wires. The invention is also embodied in a method for the manufacturing of the welded mesh of the initially described type, which is characterized by the fact that the wires of said second group are incurved before being welded, and in a way that the distance (A) between two consecutive maxima is not more than one third of the maximum mesh dimension (B) in the longitudinal direction and that the so incurved wires of the second wire group are welded with the other wires in a position that consecutive incurvation-cycles of the wires of the second group are located at random with respect to the consecutive pattern-cycles of the first wire group. Therefore, such welded mesh is made by starting up from stretching wires deformed beforehand, taking care that the ratio of the maximum mesh dimension in the longitudinal direction to the distance between two consecutive maxima of a stretching wire is at least about 3 and it being possible for each stretching wire longitudinally of the welded mesh sheet to be placed at random. Advantageously, the method described hereinbefore is carried out in such a way that first a basic netting with meshes is formed by starting from specific mesh-forming wires, then applying the stretching wires in a separate welding operation, whereby only the distribution of the stretching wires over the width of the sheet needing to be regulated as far as positioning is concerned. A positioning of each deformed stretching wire longitudinally of the netting sheet with a view to the periodicity of the configuration is no longer critical as a result of the distance between the maxima as described hereinbefore. When carrying out the method indicated hereinbefore, use is generally made of spot welding electrodes, for instance, the surface of which is so large that a good welded connection can be obtained irrespective of the position of, for instance, a stretching wire with respect to a transverse wire. The invention will hereinafter be illustrated with reference to the drawing wherein: figure 1 to 6 inclusive show embodiments of the welded mesh in accordance with the invention with rectangular meshes; figure 7 shows a welded mesh with preponderantly rhombic meshes; figure 8 shows a welded mesh with rectangular meshes and a selvedge presenting rounded shapes; figure 9 shows a welded mesh having, as said first group of wires, undulatory wires extending longitudinally of the welded mesh; and figure 10 represents a welded mesh which consists of a combination of rectangular meshes and round mesh shapes. Figure 1 shows a welded mesh 1 with rectangular meshes formed by welding together straight underformed mesh-forming wires 3 of a first group, extending transversely of the welded mesh and deformed stretching wires 4 extending longitudinally of the netting. In this way, meshes 2 are formed and it can be seen that an extra stretching wire 5 is applied for reinforcement in the longitudinal edge area of the welded mesh, at a distance from the edge wire 4 of less than half the mesh dimension (C) in the transversal direction. The stretching wire 4 has maxima 6 and 7 which have an in-between distance A, the maximum mesh distance longitudinally of the netting sheet being indicated with B. The ratio of B/A is about 3. Each stretching wire 4, 5 shows a regular arrangement of identical patterns longitudinally of the sheet. These stretching wires 4, 5 are formed on commonly known machines, e.g. by guiding the wires between a pair of crimping cylinders or wheels. The maxima 6 and 7 of two adjacent stretching wires 4 and 5 may have the same position with respect to the longitudinal direction of the welded mesh ; however, this is not necessary. The arrangement of the identical patterns of each of the stretching wires 4 and 5 is randomly positioned with respect to the arrangement of the meshes 2 of the welded mesh 1. Advantageously, as such a welded mesh is applied as fencings, it is often provided with a corrosion-resistant zinc layer whereupon a plastic layer, a sintered coloured PVC layer for instance, is applied if so desired. Figure 2 is a welded mesh as shown in figure 1; the extra stretching wires 5 are missing, however. Figure 3 is a welded mesh as in figure 2, the rectangular shape of the meshes 2 being a square shape, however. Figure 4 shows a welded mesh as in figure 3, extra stretching wires 5 having been incorporated at the edges, however, whereas figure 5 shows a welded mesh as in figure 4, the extra stretching wire dividing the outmost meshes 2 into two approximately equal halves. Figure 6 shows another variant with two extra reinforcement wires 5 at the top of the netting and one reinforcement wire at the bottom of the netting. Figure 7 shows a so-called diamond-mesh welded mesh with meshes 11 that is formed by starting from a first group of wires 12. Stretching wires 13 have been incorporated into the welded mesh and in this case as well, extra stretching wires 14 are present in the peripheral area of the welded mesh. These stretching wires 13 and 14 correspond to the stretching wires 4 and 5 of the embodiments, shown in figures 1 to 6. Figure 8 shows a welded mesh substantially corresponding to the welded mesh as shown in figure 1. The meshes 21 have a rectangular shape that is obtained by composing the netting of transversely extending wires 22 and deformed stretching wires 23. In this case, an extra stretching wire 24 has been incorporated into the upper peripheral area of the netting further-more incorporating a decorative part composed of undulatory wires 25 and 26 that are connected to one another and to transverse wires 22 through welding. The stretching wires 23 and 24 correspond to the stretching wires 4 and 5 of the embodiments, shown in figures 1 to 6. Figure 9 shows a welded mesh type substantially obtained by welding together undulatory wires 31 and 32 extending longitudinally of the welded mesh as a result of which a netting of meshes 33 are formed. The longitudinally extending deformed stretching wires 34 are applied during such netting-forming process, but advantageously after the formation of this netting ; extra stretching wires 35 being present in the peripheral areas. In the figure, the stretching wires 34 are drawn exactly at the intersections of the longitudinal wires 31 and 32. It will be clear that such a positioning is not very critical when applying spot welding electrodes with a sufficiently large surface. Slight shifts with respect to said intersection are allowable. The stretching wires 34 and 35 correspond to the stretching wires 13 and 14 of the embodiment shown in figure 7. Finally, figure 10 shows yet another wire mesh 40 with rectangular meshes 43 that is composed of transverse wires 41 and longitudinal wires 42 in the form of stretching wires. Further, ornaments composed of undulatory deformed wires 46 and 47 have been incorporated into a number of areas between two stretching wires. An extra stretching wire 45 is applied for reinforcement in the peripheral areas of the netting 40. The stretching wires 42 and 45 correspond to the stretching wires 4 and 5 of the embodiment shown in figure 1.

Claims: Welded mesh, adapted for fencing purposes, comprising a first group of wires(3; 41,46,47), extending in a longitudinal(46,47) and/or transverse(41) direction of the mesh and forming together a pattern having a periodicity in the longitudinal direction by which a number of consecutive pattern-cycles can be distinguished, and further comprising a second group of wires(4, 5; 42), extending in the longitudinal direction, each showing incurvations in the plane of the mesh showing consecutive maxima(6,7) and according to a pattern with a periodicity in the longitudinal direction, by which a number of consecutive incurvation-cycles can be distinguished, the longitudinally measured length of the wires of the second group being at least 90% of the length, measured along the wire, said first an second group of wires forming together a configuration of wire meshes, showing a maximum mesh dimension (B) in the longitudinal direction, characterized by the fact that the ratio of said maximum mesh dimension (B) to the distance (A) between two consecutive maxima is at least three, and that consecutive incurvation-cycles of the second wire group are located at random with respect to the consecutive pattern-cycles of the First wire group. Welded mesh according to claim 1, in which said ratio is at least five. Welded mesh according to claim 1 or 2, in which the incurvations in said wires of the second group are such that the deviation of said maxima (6,7) of a wire with respect to the central line of that wire is not more than 10% of the maximum mesh dimension (C) in the transversal direction of the mesh. Welded mesh according to any one of claims 1 to 3, in which the distance between two adjacent wires of said second group is less than 250 mm. Welded mesh according to any one of claims 1 to 4, in which at least two wires of the second group, at a distance from each other of less than half the maximum mesh dimension (C) in the transversal direction of the mesh, are located in the longitudinal edge area of the mesh. A method for the manufacturing of welded mesh comprising a first group of wires (3; 41,46,47) extending in a longitudinal (46,47) and/or transverse (41) direction of the mesh and forming together a pattern having a periodicity in the longitudinal direction by which a number of consecutive pattern-cycles can be distinguished, said welded mesh further comprising a second group of wires (4, 5; 42), extending in the longitudinal direction, each showing incurvations in the plane of the mesh showing consecutive maxima (6,7), and according to a pattern with a periodicity in the longitudinal direction, by which a number of consecutive incurvation-cycles can be distinguished the longitudinally measured length of the wires being at least 90% of the length, measured along the wire, said first and second group of wires forming together a configuration of wire meshes, showing a maximum mesh dimension (B) in the longitudinal direction, characterized by the fact that the wires of said second group are incurved before being welded, and in a way that the distance (A) between two consecutive maxima is not more than one third of said maximum mesh dimension (B), and that the so incurved wires of the second wire group are welded with the other wires in a position that consecutive incurvations-cycles of the wires of the second group are located at random with respect to the consecutive pattern-cycles of the first wire group.

Inventors: BRUGGEMAN FRANS, BRUGGEMAN, FRANS
Applicants: BEKAERT SA NV, N.V. BEKAERT S.A.
Application year: 1989
Main classification: B21F27
IPC codes: B21F27, E04H17