WIRE NETTING, A PROCESS AND A DEVICE FOR MANUFACTURING THE WIRE NETTING

Abstract

A hexagonal wire netting (7), a process for manufacturing such a wire netting and a device for manufacturing a hexagonal wire netting (7), the device comprising an assembly of tubes (5) for leading the wires (I) of which every other is twisted into a spiral shape, a spindle (6) assembly and a drum (8) receiving the wire netting (7), the drum (8) being provided with detent elements (21). Between each tube (5) leading the spirally twisted wire (I) and the cooperating spindle (6) a straightening guide (IO, IO′) is located having an inlet opening (13, 15) cooperating with the tube (5) and an outlet opening (12, 20) cooperating with the spindle (6). The detent elements (21 are arranged on the drum (8) in such a way that the produced wire netting (7) has meshes in which the proportion of the width (A) to the length (B) is less than 0.75.

Claims

1. A device for manufacturing a hexagonal wire netting (7), the device comprising an assembly of tubes (5) for leading the wires (1) of which every other is twisted into a spiral shape, a spindle (6) assembly and a drum (8) receiving the wire netting (7), the drum (8) being provided with detent elements (21), each spindle (6) being adapted to lead one wire (1) passing therethrough and fed by a cooperating tube (5) and to being translated back and forth as well as rotated by 540 degrees alternately with the translations, so that the wires (1) leaving the spindles (6) are braided in at least 1.5 fold braids forming the wire netting (7) to be subsequently received by the drum (8), characterized in that between each tube (5) leading the spirally twisted wire (1) and the cooperating spindle (6) a straightening guide (10, 10′) is located, having an inlet opening (13, 15) cooperating with the tube (5) and an outlet opening (12, 20) cooperating with the spindle (6), and in that said detent elements (21) are arranged on the drum (8) in such a way that the produced wire netting (7) has meshes in which the proportion of the width (A) to the length (B) is less than 0.75.

2. The device according to claim 1, characterized in that the straightening guide (10) comprises a wall (11) in a shape of a truncated cone, the smaller edge of which constitutes a central outlet opening (12) cooperating with the spindle (6), and the larger edge of which constitutes a central inlet opening (13) cooperating with the outlet of the tube (5).

3. The device according to claim 2, characterized in that the inner side of the wall (11) in a shape of a truncated cone is provided with a guiding groove (22) for assisting in the straightening of the wire (1).

4. The device according to claim 1, characterized in that the straightening guide (10′) comprises a hollow cylinder (14) having an inlet edge and an outlet edge, and being provided with an inlet wall (17) in a shape of a truncated cone, the larger edge of which is aligned with the inlet edge of the hollow cylinder (14) and constitutes the inlet opening (15) cooperating with the outlet of the tube (5), while the smaller edge of which constitutes the inlet opening (18) leading to the hollow cylinder (14), which is further provided with an outlet wall (19) in a shape of a truncated cone, the larger edge of which constitutes the outlet edge of the hollow cylinder (14), while the smaller edge of which constitutes the central outlet opening (20) cooperating with the spindle (6).

5. The device according to claim 4, characterized in that, the inner side of said inlet wall (17) in a shape of a truncated cone is provided with a guiding groove (22) for assisting in the straightening of the wire.

6. The device according to claim 1, characterized in that the straightening guide (10, 10′) is made of a plastic material.

7. A process for manufacturing a hexagonal wire netting (7) in a device comprising an assembly of tubes (5) for leading the wires (1) of which every other is twisted into a spiral shape, a spindle (6) assembly and a drum (8) receiving the wire netting (7), the drum (8) being provided with detent elements (21), and each spindle (6) being adapted to lead one wire (1) passing therethrough, the wire (1) being fed by a cooperating tube (5) and the spindle (6) being translated back and forth as well as rotated by 540 degrees alternately with the translations, so that the neighboring wires (1) leaving the spindles are braided in at least 1.5 fold braids so as to form the wire netting (7) to be subsequently received by the drum (8), characterized in that the wires (1) made of high carbon steel having tensile strength in the range of 1500-1900 MPa are used, and in that the wires (1) that are spirally twisted in the tubes (5) are being straightened before being fed into the spindles (6), the produced wire netting (7) having meshes in which the proportion of the width (A) to the length (B) is less than 0.75.

8. The process according to claim 7, characterized in that the wires (1) made of steel having carbon content from 0.71% to 1% are used.

9. The process according to claim 7, characterized in that the wires (1) are provided with an anti-corrosion coating, preferably a zinc-aluminum coating in the amount of min. 150 g/m2.

10. The process according to claim 7, characterized in that the wires (1) of stainless steel are used.

Description

[0027] Exemplary embodiments of the wire netting and the device for the manufacture of the wire netting according to the invention are shown in the drawings in which:

[0028] FIGS. 1A, 1B, 1C, 1D, 1E, and 1F show fragments of the wire netting according to the prior art;

[0029] FIG. 1G shows a fragment of the wire netting according to the invention;

[0030] FIG. 2 shows a schematic view of a fragment of the device according to the invention;

[0031] FIG. 3 shows schematically a first embodiment of the straightening guide;

[0032] FIG. 4 shows schematically a second embodiment of the straightening guide;

[0033] FIG. 5 shows a detailed view of the connection between a tube and a spindle in the device according to the invention;

[0034] FIG. 6 shows an enlarged view of a braid of two wires in a final wire netting according to the invention

[0035] FIG. 7 shows a schematic view of a drum of the device according to the invention.

[0036] As may be seen in FIG. 1G, showing a fragment of the wire netting 7 according to the invention, each hexagonal mesh of the wire netting 7 has two sides with braids and four sides without the braids. Further, each mesh has six corners: there are four corners where the side with a braid meets the side without it, and two corners (opposite to each other) where two sides without the braids meet. The width A of a mesh is defined here as the distance between the two sides with the braids, and the length B of a mesh is defined as the distance between the two corners where two sides without the braids meet.

[0037] The inventors have established that a wire made of high carbon steel having tensile strength in the range of 1500-1900 MPa may be used for manufacturing the hexagonal wire netting 7 with at least 1.5 fold braids provided that the wires have been straightened before being introduced into the spindles and that said wires are not exceedingly bent later on the receiving drum. Therefore, in the meshes of the wire netting 7 according to the invention the proportion of the width A to the length B is less than 0.75. Basing on experiments it has also been established that the most advantageous content of carbon in the steel used for the wire is in the range of 0.71% to 1%, because such a wire is sufficiently resistant and at the same time ductile to enable the manufacture of the wire netting 7 according to the invention. A higher content of carbon would make the wire too brittle while a lower content thereof would make it too ductile and with a too low tensile strength.

[0038] A preferable thickness of a wire for the manufacture of the wire netting 7 according to the invention is about 2.0 to about 4.0 mm.

[0039] FIG. 2 shows a schematic view of a fragment of the device according to the invention.

[0040] The wires 1 are brought from delivery stations 2 by means of guiding elements 3 and 4, to a tube assembly 5. The tubes 5 of the tube assembly form a row. In every other tube of the row a wire is being twisted into a spiral shape, i.e., in every other tube the wire remains straight. In FIG. 2, the wire 1 in the tube 5 is being twisted. Downstream of the assembly of the tubes 5 (as shown in FIG. 2 above the tube assembly 5) a spindle assembly 6 is located, so that the wire 1 leaving each tube 5 is passed to a cooperating spindle 6. The neighboring wires are braided with each other by the spindles 6 (the same as in the above-described state of art machine) and from the spindles 6 the ready wire netting 7 is passed to the drum 8 and then wound on a roll 9.

[0041] A specific feature of the device according to the invention is that it is provided with wire straightening guides 10. Between each tube 5, in which the wire 1 is being spirally twisted and its cooperating spindle 6, the straightening guide 10 is located.

[0042] In the first and simplest embodiment shown in FIG. 3, the straightening guide 10 is formed by a wall in the shape of truncated cone 11, the smaller edge of which constitutes a central outlet opening 12 cooperating with the spindle 6, while its larger edge constitutes a central inlet opening 13 cooperating with the outlet of the tube 5.

[0043] FIG. 4 shows an embodiment in which the straightening guide 10′ comprises a hollow cylinder 14 having an inlet edge and an outlet edge, and being provided inside with an inlet wall 17 in the shape of a truncated cone, the larger edge of which is aligned with the inlet edge of the hollow cylinder 14 and constitutes the inlet opening 15 cooperating with the outlet of the tube 5. The smaller edge of the inlet wall 17 constitutes the inlet opening 18 leading to the inside of the hollow cylinder 14. The hollow cylinder 14 is further provided on its outside with an outlet wall 19 in the shape of a truncated cone, the larger edge of which constitutes the outlet edge of the hollow cylinder, while the smaller edge of which constitutes the central outlet opening 20 cooperating with the spindle 6.

[0044] The straightening guide 10, 10′ is preferably made of a plastic material. In order to facilitate the straightening of the wire 1 passing through the guide 10 or 10′, a spiral guiding groove 22 may be located on the internal side of the truncated cone 11 or respectively 17. An exemplary spiral guiding groove 22 is visible as a broken line in FIGS. 3 and 4.

[0045] FIG. 5 shows an enlarged view of a detail D (circled in FIG. 2) of a fragment of the machine between the tube 5 and the spindle 6, where the straightening guide 10′ is mounted.

[0046] Due to the provision of the straightening guides 10, 10′ the twisted wires 1 that are made of a relatively stiff steel having high tensile strength, are being straightened prior to being introduced to the spindles 6. Subsequently, the spindles 6 impose at least 1.5 fold braiding of the neighboring wires with each other. An exemplary braid of two wires 1 is shown in FIG. 6.

[0047] Another important feature of the invention is the use of the receiving drum 8 shown in FIG. 7, having detent elements 21 arranged in such a way that the produced wire netting 7 is formed with hexagonal meshes in which the proportion of the width A to the length B is less than 0.75.

[0048] The use of the specific straightening guides 10, 10′ and the special arrangement of the detent elements 21 on the receiving drum 8 results in that the high tensile-strength wire does not brake during the at least 1.5 fold braiding which enables formation of the hexagonal netting.

[0049] Thanks to the hexagonal structure and the at least 1.5 fold braiding the wire netting will not unbraid even in case of a breakage of one wire. Upon the breakage of one individual wire (as schematically shown by scissors in FIG. 1G) the forces are transferred by the neighboring wires and the unbraiding of the wire netting is prevented by the neighboring braids because the netting is made of high tensile-strength wires. The edges of a wire netting sheet are provided with border wires or ropes, which are also made of a high tensile-strength steel and ensure an orderly shape of the netting edges.

[0050] The wire netting 7 according to the invention may be a component of a system in which conventional plates/washers are used for pressing the mounted wire netting to the slope (not shown).

[0051] As the wire netting 7 according to the invention is woven from the high tensile-strength wires, it tends to self-constrain upon braiding of the wires. Consequently, the arising hexagonal structure is elastic and the width of the band of the netting received by the drum is smaller than the maximal possible width of the band when stretched. Such an elastic structure is a sort of an energy absorber and it may be mounted on an embankment base for the purpose of catching rock chunks without the need to use absorbing spring ropes.

[0052] An additional advantage of the invention is that the wire netting 7 according to the invention enables continuous protection of large surfaces. On some embankments, the wire netting may be formed of a continuous material on the whole length of the embankment. For example, a rolled wire netting having a length of 30 m is made of continuous 40 m long wires, the 10 m reduction being caused by the hexagonal shape of the meshes. On the other hand, rhomboidal nettings may not be manufactured of the wires longer than about 4 m.