FR2734503A1 - Fabrication process for weave for welded wire lattice cable routes - Google Patents

Abstract

The process involves selection of steel wires pretreated by continuous hot galvanisation or Al-Zn alloy coating. The wires are welded together e.g. electrically to form a weave with a square or rectangular mesh, which is cleaned by high-pressure jets of air during the welding process. Alternatively a detergent is atomised by several cleaning nozzles placed on the production line beyond the welding electrodes, to remove from each joint the black smoke created during the welding. The weave is rinsed and dried in hot or cold air and its longitudinal edges are folded.

Description

 The present invention relates to a method of manufacturing a trellis sheet of welded steel wires for obtaining cable trays.

 We know sheets of this kind which generally consist of several steel wires welded perpendicularly to each other to form a trellis. These trellises are folded to obtain cable trays which allow the suspended transport of all kinds of electrical, hydraulic or other pipes.

 After folding the sheet of welded steel wire, the latter receives an anti-corrosion application such as galvanization or a plastic coating or a layer of paint or varnish.

These types of anti-corrosion coating are expensive because they require significant labor and heavy investment. In addition, steel wires are generally stored before being used and these quickly become covered with a layer of rust. Before covering them with zinc, it is necessary to treat the sheets to remove rust.

This step consists in immersing the tablecloth in a corrosive product to clean all the wires.

 It is to these drawbacks that the present invention more specifically intends to remedy.

 The purpose of the process according to the present invention is to reduce the cost of manufacturing cable trays made of welded steel wire mesh while retaining the required safety characteristics.

The process consists
- take steel wires pre-treated by continuous hot-dip galvanizing or similar method
- to solder the wires together to form a lattice-like sheet
- and to continuously clean the sheet at the weld areas.

 The implementation of the method consists in using, for the manufacture of the plies, steel wires pretreated by continuous hot galvanization or by the so-called "sendzimir" method or by continuous hot deposition of an aluminum alloy zinc. The second step of the process consists in welding the pretreated wires together to form the sheet which is in the form of a lattice with square, rectangular or other meshes. The welding is carried out for example by an electrical heating of the wires associated with a pressure, so that each wire penetrates one into the other. This known technique makes it possible to obtain a weld directly protected against rust.

 The third step of the process makes it possible to clean the strands of the sheet. Indeed, at each soldering station and near the electrodes are provided with nozzles which project air under high pressure during the welding of the wires together. The projection of pressurized air avoids the deposit of black smoke due to welding.

 A variant of the third step of the process consists in placing after the welding electrodes and on the production line several cleaning nozzles which automatically spray a degreasing product on each weld of the mesh to remove the black smoke due to the welding. It is also necessary to provide other nozzles on the production line which spray either a rinsing product essentially consisting of either cold or hot water. It is noted that the various stages of the variant are carried out continuously during the manufacture of the sheet and this in a protective tunnel for the cases of spraying of a liquid product.

 After rinsing, the tablecloth is placed in a drying space with cold or hot air.

 When all the manufacturing steps are completed, the longitudinal edges of the sheet are folded by means of male and female V-shaped dies known per se. These have adequate profiles limiting their penetration into the wires to avoid marking them. Obviously other systems can be used to fold the edges of the sheet such as folding machines or press brakes.

 The main advantage of this process is that it is inexpensive and that the pre-treated steel wires and plies do not rust during storage.

 Then, the cleaning step makes it possible to make the sheet clean without any visible and unsightly weld mark.

 It should moreover be understood that the above description has been given only by way of example and that it in no way limits the field of the invention from which one would not depart by replacing the execution details described by all other equivalents.

Claims (6)

 1. Method for manufacturing a sheet intended for cable trays in welded wire mesh, characterized in that it consists  - to take steel wires pre-treated by continuous hot-dip galvanizing or by a similar method  - to solder the wires together to form a lattice-like sheet  - and to continuously clean the sheet at the weld areas.  2. Method according to claim 1, characterized in that the cleaning is carried out during the welding of the son by means of nozzles which project air under high pressure.  3. Method according to claim 2, characterized in that the nozzles allowing the projection of air under high pressure are arranged around the welding electrodes.  4. Method according to claim 1, characterized in that the cleaning is carried out by means of several nozzles which make it possible to spray on the one hand a degreasing product under pressure and on the other hand cold or hot water for clean each weld of the tablecloth.  5. Method according to claim 4, characterized in that the cleaning is carried out in a protective tunnel.  6. Method according to claim 4, characterized in that the cleaning takes place automatically after the manufacture of the sheet.