IMPROVEMENTS IN ARMOUR

This invention relates to armour and in particular body armour capable of protecting the wearer from high velocity ammunition.

Body armour has been known for thousands of years, taking the form of animal hide, as used for instance by ancient tribes, or metal plate or chain mail armour used throughout ancient and medieval times.

Modern body armour must now withstand bullets and similar projectiles shot from firearms. Modern bullet proof armour usually comes in two types, hard body armour or soft body armour.

Hard body armour uses the same basic principles as the iron suits worn in medieval times. These are usually made of thick ceramic or metal plates which are hard enough to push out on the bullet with the same force with which the bullet pushes in, thus deflecting the bullet. However, there is a limit to the effectiveness of hard body armour particularly against high energy rounds. There comes a point where the thickness and weight of the body armour required to deflect the bullet and prevent penetration becomes too great to be practical.

Soft body armour is made from long strands of strong fibre, such as aramid (also known under the trade name Kevlar®), which are interconnected to form a dense net. This net disperses the energy of the bullet from the point of impact over a wide area. However, this soft body armour gives even less protection to high velocity rounds than hard body armour.

Consequently, it would be desirable to have body armour that was capable of offering protection against high velocity rounds such as, for instance, a round fired from a P90 sub-machine gun. This will penetrate through many forms of current body armour, including the body armour issued to police forces in the UK.

In the first aspect of the invention there is provided armour for protecting against a projectile, said armour comprising an inner protective layer and outer protective layer with a gap therebetween, said gap containing a fluid, wherein said outer protective layer is sufficiently rigid such that a projectile passing through it causes a pressure wave in said fluid, said pressure wave resulting in said projectile fragmenting or tumbling prior to impacting said inner protective layer.

The inventor has discovered that when a projectile, in particular a high velocity projectile, passes through the rigid outer layer this penetration creates a pressure wave in the gap. This pressure wave then fragments the bullet or at least causes it to tumble, simulating its action upon penetrating soft tissue. The relatively low energy fragments and/or tumbling bullet are then stopped by the inner protective layer.

Body armour with two layers separated by an air gap is known. These comprise two soft layers of material such as Kevlar® and aim to reduce blunt trauma. Blunt trauma is caused by the energy which passes through the vest due to the vest deforming when struck by a bullet. In these designs the bullet is stopped completely by the first outer layer and the second layer protects the user's body from the blunt trauma caused by the deformation of this outer first layer. Examples of theses devices can be found in Canadian application CA2169415 and US patent US0505947A. However these designs would not protect the user from high powered rounds such as those described, as the soft outer layer would deform when struck. As a result the bullet then would pass through this layer without causing the pressure waves in the gap (which is likely to have been substantially closed anyway) needed to fragment the bullet. Consequently the bullet retains much of its energy and also passes through the second layer and into the wearer.

Preferably the armour is body armour to be worn by a person, although it may be used to armour an armoured vehicle or anything else which requires protection from high velocity rounds.. Preferably this body armour has a soft inner protective layer such as that used in standard issue soft body armour. This may consist of Kevlar® aramid fibre

or any other suitable material. The outer layer may consist of ceramic or Kevlar® reinforced fibreglass. The fluid contained in said gap may be air.

In another embodiment the armour further comprises a spacer element in said gap between the two protective layers. This spacer element may consist of a substantially ellipsoidal or semi-ellipsoidal, or substantially spheroidal or semi-spheroidal elements.

These ellipsoidal or semi-ellipsoidal, or substantially spheroidal or semi-spheroidal spacer elements may have flattened ends. These elements may be arranged in an array.

Said array may comprise a single layer. The spacer may comprise VARI (Vacuum Assisted Resin Injection) woven glass or a carbon fibre/Kevlar aramid fibre hybrid.

In a further aspect of the invention there is provided an armoured vehicle comprising the armour described in any or the proceeding paragraphs. Said vehicle preferably has two hard protective layers.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described, by way of example only, by reference to the accompanying drawings, in which:

Fig. 1 shows schematically armour according to a first embodiment of the invention;

Figs. 2a - 2d show in stages what happens when a bullet is fired at the armour of Fig. 1 ;

Fig. 3 shows a further embodiment of the invention with space; and

Fig. 4 shows the embodiment of Figure 3 with alternative space design.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Fig. 1 shows armour according to a first embodiment of the invention. This armour, when used as body armour, comprises a hard outer protective layer 10 and a soft inner

protective layer 12. Between these two layers is an air gap 14. The hard outer layer 10 may comprise ceramic or Kevlar® reinforced fibreglass while the inner layer 12 is essentially standard issue soft body armour suitable for normal velocity rounds. (Class DIA).

Neither of these layers are capable of preventing penetration of certain very high velocity rounds such as those fired from the FN P90 sub-machine gun, by themselves. However, Figures 2a — 2d show how these protective layers 10, 12 in the arrangement of Figure 1 can protect the wearer from these types of high velocity rounds.

Fig. 2a shows a high velocity bullet 20 strike the hard outer layer 10. As explained above, this outer layer 10 cannot be made strong enough to prevent the bullet from penetrating through it, while leaving ensuring that it is light and practical enough to be of any use. Consequently, the bullet 20 penetrates this first layer.

Fig. 2b shows the bullet 20 having penetrated through the first layer 12. Pressure waves 22 have resulted in the gap 14. These pressure waves 22 are very powerful and result in the bullet 20 fragmenting.

Fig. 2c shows the fragments 24 of the bullet formed after the bullet fragments. These fragments continue to travel towards the wearer. However, the fragments have a much smaller mass than the original bullet and therefore considerably less energy. As a result, as shown in Figure 2d, these fragments can be stopped by a standard issue soft body armour panel 12 which forms the second protective layer. Therefore this armour is capable of preventing any penetration of a high velocity round into a wearer's body.

The downside of using a simple air gap between the two layers 10,12 is that it is difficult to keep these protective layers 10,12 separate and therefore ensure the presence of a sufficient gap. Furthermore it is important to prevent the outer layer deforming and closing the gap. Normal spacers naturally produce areas where there are no gap, in that the gap is filled with the spacer itself. Consequently if a bullet were to hit this area it would not encounter the gap, and therefore would not fragment. Instead, providing it

has sufficient power, it would pass completely through the jacket and into the wearer. It is possible to attempt to place the spacers in strategic positions away from major arteries and organs, although this is obviously not an ideal solution as any bullet entering the body can be fatal and even if it is not, it will still cause significant injury.

To address this, it is proposed to use spacers of a hollow spheroidal design or of a hollow semi-spheroidal design. Fig. 3 shows such an arrangement. This shows, as before, the two protective layers 10,12 with air filled gap 14 in between. However, also in this gap is an array of spacers 30 which are substantially spheroidal, although they have flattened ends in order to increase the surface area in contact with the protective layers allowing good adhesive connection. These spacers 30 are essentially hollow egg shaped objects (although with symmetrical top and bottom halves). Consequently, this array of spacers 30 resembles a closed egg carton, in particular an egg carton for carrying small eggs such as quail eggs. These spacers preferably fill the entire void, although they do not need to be arranged in a strict array, or in an array at all, but could be positioned in strategic positions.

Fig. 4 shows an alternative arrangement whereby the spacers 40 are semi-spheroidal hollow solids, again flattened to increase the surface area in contact with the outer protective layer. Therefore an array of these spacers resembles an egg tray, or an open egg carton. Again these spacers can be arranged in an array or at strategic points..

The spacers may be made of VARI (Vacuum Assisted Resin Injection) woven glass or a carbon fibre, Kevlar, aramid fibre hybrid.

These spacers 30 are shaped to ensure that the inner and outer protective layers are kept separate. The spheroidal shape prevents the outer layer deforming and closing the gap while also ensuring that any bullet passing through the first layer will at some point in its travel meet an air gap which, due to the pressure waves which result, causes the bullet to fragment or tumble prior to hitting the inner protective layer 14.

Although this invention has been described in relation to personal body armour, it is possible to envisage the use of any of any of the embodiments described above for armoured vehicles or tanks, or in any other situation or on any other object which requires armouring.

The embodiments described above are for the purposes of illustration only and other embodiments are envisaged without departing from the spirit and scope of the invention. In particular, the fluid between the two protective layers need not be air but could be any other gas or liquid, provided that it results in the bullet fragmenting in the same way. Also any of the layers or spacers may be made of materials either already in existence, or developed in the future, which are suitable for carrying out the invention.