Description

Technical Field

[0001] The invention relates to an assembly of a welded wire mesh panel and one or more frames.

The invention also relates to a wall or a ceiling reinforced by one or more of these assemblies.

Background Art

[0002] PCT application PCT/EP2020/065355 discloses a chain link steel wire mesh provided with a pattern of marks that indicate the places where the chain link steel wire mesh must be attached to a wall or ceiling.

[0003] The advantage of these marks is that they enable a fast and secure attachment of the chain link steel wire mesh to a wall or a ceiling. Bolts can be positioned correctly in an efficient way according to a regular pattern provided by the marks. The marks are provided by a tape attached to the chain link steel wire mesh.

[0004] However, having regard to the rough environment of tunnels and underground mining, these tapes often do not survive installation of the chain link steel wire mesh to the ceiling or the wall. Even worse, due to the friction of the chain link steel wire mesh against the ceiling or the wall, these tapes risk to break and disappear before reaching the intended position.

Disclosure of Invention

[0005] It is a general object of the invention to avoid the drawbacks of the prior art.

[0006] It is a particular object of the invention to provide for a marking that is robust and survives installation.

[0007] According to a first aspect of the invention, there is provided assembly of a welded wire mesh panel and one or more frames. The welded wire mesh panel is adapted to be tied to a wall or a ceiling at one or more predetermined spots. One or more frames are attached to the welded wire mesh panel so that these frames surround the predetermined spots. These frames usually form a regular pattern on the welded wire mesh panel.

[0008] In comparison with a chain link steel wire mesh that is flexible, the welded wire mesh panel is a stiff panel and, as such, more robust than the chain link steel wire mesh. The frames are also stronger and more robust than the tapes. In addition, the frames surround the spots of attachment to the wall or ceiling. In other words, cable bolts and or threaded bolts are inserted inside the frames and do not destroy the frames. It is hereby understood that the prior art tapes indicate the exact point of attachment, so that cable bolts or bars inserted at these points are likely to break and destroy the tapes. The combination of stronger frames on stiffer panels and the form of the frames offer a robust solution and guarantee that the marking frames survive the installation.

[0009] In a preferable embodiment, the frames have a color that is visually different from the color of the welded wire mesh panel. The terms ‘visually different’ refer to a situation where a human being with average visual capability can notice the color difference.

[0010] The frames are preferably made of plastic, e.g. from a polymer, most preferable a polymer with a high level of tensile strength such as polyamide.

[0011 ] Each of the frames is attached to the welded wire mesh panel by at least two fixation points. Four fixation points are preferred since the welded wire mesh panels may be subjected to torsions during installation.

[0012] The frames may be attached to the welded wire mesh panel by means of a glue or after receiving a short local heating shot. Preferably, however, the frames are attached to the welded wire mesh panel by an elastic coupling, such as a snap-in construction. A snap-in construction allows to fix the frames with a simple press to the welded steel wire mesh panel.

[0013] The welded steel wire mesh panel has a first side. This first side is intended to be in contact with or to face the wall or ceiling. The wire mesh panel has also a second side. This second side is remote from the wall or ceiling. The frames are positioned remote from the wall or ceiling in order to secure them as much as possible.

[0014] The welded steel wire mesh panel has two sets of parallel steel wires. A first set of parallel steel wires forms the first side and a second set of parallel steel wires forms the second side.

[0015] The frames are preferably attached to said first set of parallel steel wires.

[0016] The first set of parallel steel wires cross the second set of parallel steel wires. Two adjacent steel wires of the first set and two adjacent steel wires of the second set form a mesh, for example a mesh of a rectangular form. Preferably, each frame surrounds a single mesh.

[0017] According to a second aspect of the invention, the assembly according to the first aspect is used to reinforce a wall or a ceiling.

[0018] Preferably the tying means such as cable bolts that attach the assemblies to the wall or the ceiling are positioned inside the frames.

Brief Description of Figures in the Drawings

[0019] FIGURE 1 shows an assembly of a welded steel wire mesh panel and one or more frames.

[0020] FIGURE 2 is a detailed view of a one frame attached to a welded steel wire mesh panel.

[0021 ] FIGURE 3 is a cross-section showing how the frame is fixed to one wire of the welded steel wire mesh panel. Mode(s) for Carrying Out the Invention

[0022] FIGURE 1 shows an assembly 10 of a welded steel wire mesh panel and one or more frames. The welded steel wire mesh panel has a first set of parallel steel wires 12 and a second set of parallel steel wires 14. Both the steel wires 12 and 14 have a diameter ranging from 3.0 mm to 8.0 mm, for example from 4.0 mm to 6.0 mm.

[0023] Plastic frames 16, for example frames from polyamide, are attached to the steel wire mesh panel at regular distances and form a regular pattern.

[0024] Referring now to FIGURE 2, two adjacent steel wires 12 and two adjacent steel wires 14 cross each other perpendicular and form a square mesh 18 of 10 cm x 10 cm. A frame 16 surrounds such a mesh 18. The distance between two frames 16 depends upon the geomechanical conditions and may range from 50 cm to 2.0 m, for example from 1.0 m to 1.5 m. The thickness of the plastic frame 16 ranges from 1 mm to 3 mm.

[0025] FIGURE 3 explains the way a frame 16 is preferably attached to the welded steel wire panel. In cross-section the frame 16 has four parts 30 that from a circular arc of somewhat more than 180°. These parts 30 from an elastic connection with steel wires 12.

[0026] The steel wires are preferably plain low carbon steel wires. Plain low carbon steel wires have a carbon content ranging from 0.05 wt % to 0.25 wt %. A typical low carbon composition is 0.25 wt% carbon, 1 .0 wt% manganese, 0.2 wt % copper, 0.28 wt % silicon, 0.04 wt % phosphorus and 0.05 wt % sulphur.

[0027] The steel wires have a zinc coating or a zinc aluminium coating, preferably via a hot dip operation.

[0028] A zinc aluminium coating has a better overall corrosion resistance than zinc. In contrast with zinc, the zinc aluminium coating is temperature resistant. Still in contrast with zinc, there is no flaking with the zinc aluminium alloy when exposed to high temperatures.

[0029] A zinc aluminium coating may have an aluminium content ranging from 2 per cent by weight to 12 per cent by weight, e.g. ranging from 3 % to 11 %.

[0030] One preferable composition lies around the eutectoid position: Aluminium about 5 per cent. The zinc alloy coating may further have a wetting agent such as lanthanum or cerium in an amount less than 0.1 per cent of the zinc alloy. The remainder of the coating is zinc and unavoidable impurities.

[0031 ] Another preferable composition contains about 10% aluminium. This increased amount of aluminium provides a better corrosion protection then the eutectoid composition with about 5% of aluminium.

[0032] Still another preferable composition is a zinc aluminium alloy that comprises 2 % to 10 % aluminium and 0.2 % to 3.0 % magnesium, the remainder being zinc. An example is 5% Al, 0.5 % Mg and the rest being Zn.

[0033] Other elements such as silicon (Si) may be added to the zinc aluminium alloy coatings mentioned above.

[0034] List of Reference Numbers

10 Assembly of welded steel wire mesh and one or more frames

12 First set of parallel steel wires

14 Second set of parallel steel wires

16 Frame

18 Mesh inside frame

30 Part of frame that forms snap-in connection with steel wire