WO1992000496A1

WO1992000496A1 - Yielding barriers

Info

Publication number: WO1992000496A1
Application number: PCT/EP1991/001143
Authority: WO
Inventors: David Macbeth Macwatt
Original assignee: Passive Barriers Ltd.
Priority date: 1990-06-26
Filing date: 1991-06-20
Publication date: 1992-01-09
Also published as: GB9014205D0; AU8065991A

Abstract

Armour protection material for protection against ballistic, flame and blast attack, in the form of a wire mesh structure where parallel weft rods (1) of hard metal such as tungsten, titanium or austenitic steel are linked by flattened helix wires (2) of a yielding material such as mild steel.

Description

YIELDING BARRIERS

The present invention relates to barriers for protection against attack, particularly against ballistic projection and also flame or blast or other forms of attack which can arise in the cases of civil or military unrest.

Various armour pl_ating systems are known for this purpose and generally the main problem is weight, for example an armoured land vehicle (e.g a land Rover [Registered Trade Mark] kind of vehicle) may have up to three times the weight of a similar vehicle without armour plating.

The present invention is concerned with the problem of providing an armour plating system which is lighter and more convenient in use than systems used hitherto. In solving this probler. τhe inventor nas realised that weight alone is not the key to good armour protection, but what is needed is a structure which can dissipate energy and yield in a gradual controlled way.

Accordingly the present invention provides an armour protection material for protection against ballistic, flame and blast attack in the form of a mesh structure of interwoven wires, characterised in that the mesh structure is formed from a plurality of substantially parallel weft rods of hard metal linked by a warp of a yielding material.

The weft rods will generally consist of a hard tough metal such as tungsten or titanium, or of a hardened steel such as a carbon, magnesium or stainless/ austenitic steel having a high Brunei hardness factor. By contrast the warp material will generally consist of a softer more ductile material such as mild steel, copper or aluminium wire or non-metallic material having similar 'properties. The shape of the warp material, e.g helical, may also contribute to its realised properties in practice.

In the simplest form of the invention the warp may consist of a single helix of wire linking each adjacent weft rod. Prefer_ably the single helix is doubled, trebled quadrupledupand has a flattened shape in cross-section.

In practice therefore a mesh is provided which has flexibility and is of a firm consistency for assembly, but can yield in use so as to absorb energy. Thus, missiles projected by hand or by some form of armament can be resisted effectively.

To work best in this respect, the flattened helix has advantage because it enables the weft rods to be slig spaced and so that any yielding which occurs is due to direct stretching of the wire from which the helix is formed rather than from distortion of the helix shape.

Thus, the mesir .material is able to stand the impact of projectiles due to absorption of the kinetic energy, and moreover these projectiles are likely to be absorbed in the mesh rather than being shrapnelised or ricocheted. A further advantage over conventional armour plating is that the flexibility of the material enables it to be shaped round equipment which previously could not have armour plating provided in a convenient manner, for example pivot steered vehicles and roll up/down ballistic barriers.

Various applications of the material therefore arise. Material can be affixed to a finely engineered frame between existing metal work and trim. The advantages of light weight are that less engine power is needed and there is a reduction of axle weight, ground pressure, fuel and cost. The material can be used around cabs and engines and round cargo areas in the form of cages or shields or drapes to protect sensitive c_argo, fuel, am_j_unitio.n and personnel. In hot climates the particular structure of the invention is beneficial over other forms of armour platings since the structure allows for passage of air.

External shields can be made of the mesh material to minimise the effect of cluster bombs, magnetic explosive devices etc. on armoured vehicles. The material can be used around particularly vulnerable parts of vehicles such as their steering and drive mechanisms.

The material can be used for window protection particularly in the form of a roll down blind which can be rolled down on the attack side at any given moment while still allowing for operational visibility.

The material can be used for protecting other vulnerable parts of vehicles such as radiators, oil coolers, hydraulic pipes and rams, engines and winches.

The material can be used or driver protection in public vehicles such as buses and taxis, for example for protection against mugging.

The material can be used in ences as a peripheral barrier. A virtue of the flexibility of the material is that it can be easily and rapidly deployed. Use of a double skin of the mesh material is effective as a shield to stop yenicles from breaking through a barrier.

Perimeter fencing can be provided in utilising the mesh of the present invention.

The material can be used as a safety net for protection of public places, work sites, oil rigs, roads and railways, particularly for protection against falling debris or deliberately launched missiles. In this respect bec_ause of its mesh properties and tne fact that air can normally pass through, it does not -create problems due to wind stress or require as much support as a closed sheet material would.

The material can be used for other safety screen purposes such as protecting against suspect packages in post offices and other baggage handling areas such as shops and airports.

The material can be used in rapid deployment as a protection screen. For example a barrier can be erected against unexploded munitions or between the public and a nigh risk situation such as involving a terrori t/ hostage. It c_r-n be used in the same way for V.I.Ps and for proτecτ-ion of public buildings where personnel may be exposed to danger.

The material can also be used in shipping and oil rig situations for examples for protection against hawser and winch cable whiplash and also for use in civil engineering situations such as in mines and quarries and tunnels. It can also be used in animal husbandry, stud farms, quarantine situations, fish farming, prisons, police, customs and excise, nuclear power generation, toxic/drug/chemical risk, and other dangerous installation situations where protection of personnel is required.

A number of embodiments of the invention will now be described by way of example with ref-er-sace to the accompanying diagrammatic drawings in wnich:

Figures 1, 3, 5, 7 and 9 show plan views of five forms of mesh in accordance with the invention and

Figures 2, 4, 6, 8 and 10 show side elevations -of each these five forms of mesh. - 7 -

Referring to Figure 1 , the mesh consists of a plurality of substantially parallel weft rods 1 of hardened steel (stainless/austenitic) having a high Brunei hardness factor. These are linked together by a plurality of parallel helixes 2, of mild steel wire which form the w_arp material. Each alternate helix 2 or 3 is wound in the opposite sense so that they nest within one another and provide a stable structure where tensions are evened out. ^' Each helix is doubled up, 2a, 2b so _as to provide a degree of frictional constraint within the structure and is flattened (see Figure 2) so that any stretching of the structure occurs as a result of stretching individual wires rather than of flattening the coils of the helix.

Figures 3 and -+ show a similar arrangement where the helix wires 2 are trebled up as 2a, 2b and 2c. In this case for the same size of structure, the trebled up wires will normally be of smaller size, i.e bore, than those of the Figure 1 arrangement. In other respects the structure is the same and in each case it will be noted that the mes is open to the extent that air can pass through and will have flexibility through the capability of the helixes rotating about the weft rods. This means in practice that a sheet of the material can be rolled up or can be bent around a former or non-flat object. Page missing at the time of publication

Figures 5 and 6 show a further form where the warp material is formed from quadrupled up helixes 2a, 2b, 2c and 2d. This increases the frictional effect between individual wires.

Figures 7 and 8 show an arrangement where the warp material is of the same size as the Figure 5 arrangement but with only two wires forming each helix. This provides greater air spaces within the mesh structure and is therefore useful when visibility or greater air flow is necessary, such as in rolled up window blinds of military vehicles or in hot climate usages.

Figures 9 and 10 show another form where a single wire forms each helix, but each helix overlaps several warp rods, in the example shown three. This is another way of achieving friction between individual warp material wires.

The various mesh arrangements described may be made up to stand alone with appropriate support, such as roller blind assemblies in vehicles or light framework structures in perimeter fencing, or may be used as a composite with other materials. For example it can be used in conjunction with other armouring sheet materials such as anti-ballistic plastics sheeting, fibre glass, kevlar, polyester or even plywood; or it can be used adjacent other solid armour plating.

When used in a composite or conjunctive arrangement, if the mesh material is on the attack side, its inherent structure enables bullets or other projectiles to be broken up in a way which minimises the risk of fragmentation, rocochets, or shrapnelisation. For example hanging the mesh on the inner walls of a ship bridge or tank cabin reduces the risk of personnel being killed by internal ricochets of an armour piercing projectile.

Claims

- 13-CLAIMS

1. An armour protection material for protection against ballistic, flame and blast attack in the form of a mesh structure of interwoven wires, characterised in that the mesh structure is formed from a plurality of substantially parallel weft rods (1) of hard metal linked by a warp (2) of a yielding material.

2. An armour protection material according to claim 1 characterised in that the warp is at least one single helix of wire linking adjacent weft rods.

3. An armour protection material according to claim 2 characterised in that there is a plurality of single helices (2a, 2b, 2c) liking each adjacent pair of adjacent weft rods.

4. An armour protection material according to claim 2 or claim 3 characterised in that each single helix is flattened in form so that any impact load is taken by stretching of the wire rather than distortion of the helix shape.

5. An armour protection material according to claim 1 characterised in that each warp (2) is a flattened helix linking and overlapping a plurality of adjacent warp rods.

6. An armour protection material according to any one of the preceding claims characterised in that alternate helices (2, 3) are wound in opposing senses.