EP1746379B1 - Reactive armour with improved efficiency - Google Patents

Abstract

The armor has a case (2) comprising a front wall (3) and for being fixed to an external wall (4) of a vehicle. The case encloses five reactive modules (5a-5e) each comprising a metal plate (6) on which an explosive sheet (7) is applied. The plates (6) are disposed along an orientation inclined relative to a missile arrival direction (delta ). The explosive sheets are connected to an explosive layer (9) by relay explosive tabs (10), where the layer is integrated to the front wall.

Description

The technical field of the invention is that of reactive shielding.

Reactive armor is well known to a person skilled in the art, for example by the patent EP161390 . They use at least one explosive sheet which is arranged in contact with a metal plate or between two metal plates, the whole being placed in a housing which is attached to a vehicle.

The US-5824941 describes an explosive sheet framed by an upper metal plate and a lower plate of glass or plastic. Each explosive sheet is connected to a transfer explosive sheet disposed at the bottom of the box in the vicinity of the wall to be protected. When a projectile hits the target, either it hits the transfer plate or it hits the lower sheet. In the first case, the target is reached right away which goes against the goal. In the second case, we first ensure the initiation of an explosive sheet then that of the transfer sheet and finally the other sheets of explosive, which reduces the effectiveness of the shielding.

When a hollow charge jet impacts the outer wall of the housing, the explosive sheet is initiated by the shock and projects a plate in front of the jet. This projected plate consumes the hollow charge jet which then no longer has enough energy to perforate the wall of the vehicle.

The known reactive shields are effective against hollow charge projectiles but their effectiveness against kinetic energy projectiles (or arrow projectiles) is less.

Indeed, the latter today have a very important length (L / D> to 10) which ensures perforating efficiency even on armor equipped with reactive protections.

It is the object of the invention to provide improved reactive shielding having, under reduced bulk, increased efficiency against kinetic projectiles.

Thus, the subject of the invention is a reactive shield comprising at least one metal plate arranged in a housing comprising a front wall to be traversed by a projectile, metal plate that can be projected as a result of the initiation of at least one explosive sheet applied to the plate, reactive shielding comprising at least two projectable metal plates, the sheets of explosives carried by the plates being all connected to an initiation device which is integral with the front wall, characterized in that the initiation device comprises at least one layer of explosive integral with the front wall and connected to the different leaves by explosive means of transmission.

Alternatively, the initiation device may comprise at least one explosive layer integral with a side wall of the housing.

The projectable plates may be substantially parallel to each other.

The plates can be separated from each other by the same distance.

The shielding may comprise at least three parallel plates.

The plates may form an angle with respect to a direction which is intended to be positioned substantially horizontally.

The plates may be arranged to be projected towards a lower part of the housing or, alternatively, arranged to be projected towards an upper part of the housing.

• la figure 1 est une vue en coupe transversale d'un blindage réactif selon l'invention,
• la figure 2 est une vue de dessus de ce blindage réactif, le boîtier étant coupé suivant le plan AA de la figure 1,
• les figures 3a, 3b, 3c, 3d, 3e et 3f sont des vues schématiques montrant différentes étapes du fonctionnement du blindage selon l'invention.

The invention will be better understood on reading the following description of a particular embodiment, description made with reference to the accompanying drawings and in which.

• the figure 1 is a cross-sectional view of a reactive shield according to the invention,
• the figure 2 is a top view of this reactive shield, the housing being cut according to the plane AA of the figure 1 ,
• the Figures 3a, 3b , 3c, 3d , 3rd and 3rd are schematic views showing different steps of the operation of the shield according to the invention.

Referring to figures 1 and 2 , a reactive shield 1 according to the invention comprises a housing 2 having a front wall 3. The housing 2 is intended to be fixed to an outer wall 4 of a vehicle (not shown). Fixing will be done using appropriate means such as tabs or flanges that are not shown here.

The housing 2 contains several reactive modules 5 (here five modules: 5a, 5b, 5c, 5d and 5e).

Each reactive module comprises a single metal plate 6 on which a sheet is applied 7. In a conventional manner each sheet 7 is glued to the plate 6 considered.

According to an essential characteristic of the invention, the metal plates 6 are disposed in an inclined orientation with respect to a direction δ which is the direction of arrival of the threat (projectile) that seeks to counter the shielding. This direction is substantially horizontal. Thus each plate 6 forms an angle α with respect to the direction δ which is here perpendicular to the wall 3. This angle α is between 5 ° and 45 °).

All the plates 6 are parallel to each other and they are separated by a distance d which is a function of the threat and the definition of the reactive modules 5. This distance may be between 20 mm and 150 mm.

The plates are fixed to the casing 2 by appropriate means, for example here by welded brackets 8.

The various explosive sheets 7 are connected to an initiation device which is integral with the front wall 3. This initiation device here comprises an explosive layer 9 which is bonded to the front wall 3 and which is connected to the different sheets 7 by explosive transmission means, for example glued relay explosive tongues 10.

The explosives constituting the sheets 7, the layer 9 and the relay tongues 10 may be different depending on the desired characteristics (speed of detonation, sensitivity).

The front wall 3 does not play a role of shielding here. It can therefore be a thin steel sheet or be made of a lightweight material such as an aluminum alloy. The plates 6 are made of metal material, for example shielded steel.

The reactive shield according to the invention will preferably be arranged such that the direction δ is substantially horizontal. In addition, the explosive sheets 7 will be placed above the plates 6. Thus the plates 6 will be projected downwards (B) during the initiation of the shielding. We spotted on the figure 1 the orientation of the screen 1 by the letters H (High) and B (Bottom).

The operation of the shielding will now be described with reference to Figures 3a to 3f .

These figures do not show the outline of the housing 2 or the fastening means 8 of the modules 5.

The figure 3a shows the shield 1 at the moment of the impact of a projectile arrow 11 on the front wall 3.

Whatever the point of impact of the projectile, the shock causes the initiation of the explosive layer 9 ( figure 3b ).

The detonation velocities in explosive materials are in the range of 6000 to 8000 m / s. Thus, well less than one millisecond after the impact, the explosive layer 9 transmitted the detonation to all the tongues 10 ( figure 3c ). The latter practically simultaneously initiate the explosive sheets 7 which project all the plates 6 ( figure 3d ). Each plate is projected with a speed Vp of the order of a few hundred meters per second.

Thus, while the projectile 11 continues its progression through the shielding housing, it receives the impacts of several plates that reach successively and with an incidence of the order of angle α.

These repeated shocks cause the fragmentation of the projectile 11 into several pieces (11a, 11b, 11c, 11d) which are also strongly deflected and which have a very low perforating efficiency ( Figures 3e and 3f ).

Compared with the known shieldings, it is therefore ensured here not only a consumption of a portion of the energy of the projectile 11 but also the impacts on the latter are multiplied by the structure associating several parallel reactive modules. Thus the pieces of the projectile are sheared and destabilized by communicating to the latter several successive shocks in directions intersecting the axis of the projectile.

The skilled person will easily parameter the shield according to the invention according to the characteristics of the projectile he seeks to counter. He will be able to play on the number of reactive modules 5, on the value of the angle α as well as on the distances d between each module 5.

It will also be possible to adopt different angles α for each module and to provide different distances d between the plates 6 of the modules.

It can be seen from the description that the effectiveness of the shielding according to the invention is all the greater as the impact of the projectile intervenes in the lower part. Indeed, the lower the impact, the more the number of plates impacting the projectile is important.

It is therefore unnecessary to carry out shielding according to the invention comprising a too large number of modules. It will be preferable to juxtapose several shields according to the invention each comprising 3 to 6 modules.

Different variants are possible without departing from the scope of the invention.

It is thus possible to arrange the modules with a reverse orientation (explosives 7 arranged below the plates 6 so plates 6 projected upward H). Such a provision will reduce the shock received by the vehicle. The reactive shielding has been described with a front wall 3 vertical and perpendicular to the direction δ input of the threat 11. It is of course possible to provide a front wall inclined relative to the direction δ.

When integrating a shield in a vehicle, the shielding should be oriented so that the reactive modules are inclined with respect to the driving direction δ (in principle horizontal). It is therefore quite possible to define a reactive shield in which the reactive modules 5 will be perpendicular to the front wall 3 of the housing. It will be sufficient in this case to incline during assembly the housing (and therefore the modules) relative to a horizontal plane.

It is also possible to define a shield according to the invention in which the reactive modules are arranged in planes parallel to each other but which are not parallel to a horizontal plane. The skilled person will choose the spatial orientation of the reactive modules as a function of both the threat it seeks to counter and the constraints of integration into a vehicle.

It is finally possible to design an initiation device comprising at least one explosive layer which is integral with a side wall of the housing. This layer will be provided in addition to the integral layer of the front wall and will be connected thereto (and the reactive modules) by pyrotechnic transmission means. Such a variant will counter a threat arriving on the armor in a direction that does not cut the front wall.

Claims (8)

1. Reactive armour (1) incorporating at least one metallic plate (6) positioned in a case (2) comprising a front wall (3) intended to be perforated by a projectile, such metallic plate able to be projected further to the ignition of at least one sheet of explosive (7) applied to the plate (6), reactive armour incorporating at least two projectable metallic plates (6), sheets of explosive (7) carried by the plates all of which are connected to an ignition device (9) integral with the front plate (3), characterised in that the ignition device incorporates at least one layer (9) of explosive integral with the front wall (3) and connected to the different sheets (7) by explosive transmission means (10).
2. Reactive armour according to Claim 1, characterised in that the ignition device incorporates at least one layer of explosive integral with a side wall of the case.
3. Reactive armour according to one of Claim 1 or 2, characterised in that the projectable plates (6) are substantially parallel to one another.
4. Reactive armour according to one of Claims 1 to 3, characterised in that the plates (6) are separated from one another by the same distance (d).
5. Reactive armour according to one of Claims 1 to 4, characterised in that it incorporates at least three parallel plates (6).
6. Reactive armour according to one of Claims 1 to 5, characterised in that the plates (6) form an angle (α) with respect to a direction (δ) likely to be positioned substantially horizontally.
7. Reactive armour according to Claim 6, characterised in that the plates (6) are arranged so as to be projected in the direction of a lower part (B) of the case (2).
8. Reactive armour according to Claim 6, wherein the plates (6) are arranged so as to be projected in the direction of an upper part (H) of the case (2).

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