GB2517664A

GB2517664A - Warhead comprising two shaped charges

Info

Publication number: GB2517664A
Application number: GB9815558.3A
Authority: GB
Inventors: Alain Kerdraon; Philippe Le Breton
Original assignee: Nexter Munitions SA
Current assignee: Nexter Munitions SA
Priority date: 1998-07-10
Filing date: 1998-07-10
Publication date: 2015-03-04
Anticipated expiration: 2018-07-10
Also published as: GB2517664B; GB9815558D0

Abstract

The warhead of the invention comprises at least two shaped charges, one front charge (3a) and one rear charge (3b), coaxially arranged one behind the other in a casing (2), the front charge and the rear charge being capable of being relocated one in relation to the other in trajectory before they are initiated, whilst both remain firmly attached to the casing, the warhead being characterised in that the front and rear charges are separated by a telescopic protective screen capable of moving, when the charges are moved apart, from a transportation position, in which it substantially follows the profile of a covering (6b) of the rear charge (3b), into an active position in which its axial space requirement is reduced.

Description

The technical field of the invention is that of

warheads comprising at least two shaped charges.

Antitank warheads comprising two concave charges which are arranged one behind the other and which are initiated in sequence are already known.

These warheads (conmonly called tandem warheads) are intended for the purpose of attacking those armoured targets which are provided with reactive forms of over-protection.

They generally comprise a front, small-calibre charge which is intended to initiate a reactive form of over-protection or else pierce a hole in the latter.

The main charge having the calibre of the warhead is initiated a short time after the front charge.

* 15. These charges are well adapted to attack over-protected armoured targets. On the other hand, they are not very effective against hard targets, such as concrete walls that are of a considerable thickness (greater than lm).

In fact, the diameter of the front charge is too small to play an effective part in the perforation of said targets.

It is known, moreover, that it is possible to design tandem warheads in which the front and rear charges are substantially of the same calibre (see, for example, the patents FR255287O, US4004515 and US3358780). In the case of such warheads, it is necessary to arrange the front charge at a distance of at least 2 calibres from the rear charge in order to avoid damage to the latter as a result of detonation of the front charge (this distance may exceed 5 calibres depending on the given delay between initiation of the front and rear charges).

The result of this is a warhead that is of a considerable length, this complicating its implementation; the length of the warhead will also be 2..

all the more considerable since the chosen charge calibre will need to be considerable to guarantee perforation of a hard target.

A warhead is known from the patent FR2712681, in S which the front and rear charges can be displaced one in relation to the other before initiation in order to avoid a situation where the detonation of the front charge interferes with the rear charge.

However, the charges described in this document are positioned on either side of a fixed screen. The result of this is that, in the contracted position, -space is required axially and this again is too much.

It is the object of the invention to put forward a warhead which does not have such disadvantages.

15. The warhead according to the invention therefore has considerable perforating capacity despite taking up a reduced amount of space axially.

The subject-matter of the invention is therefore a warhead which comprises at least two shaped charges, one front charge and one rear charge, coaxially arranged one behind the other in a casing, the front charge and the rear charge being capable of being relocated one in relation to the other in trajectory before they are initiated, whilst both remain firmly attached to the casing, said warhead being characterised in that the front and rear charges are separated by a telescopic protective screen capable of moving, when the charges are moved apart, from a transportation position, in which it substantially follows the profile of a covering of the rear charge, into an active position in which its axial space requirement is reduced.

According to a first embodiment of the invention, the screen is formed by a plurality of concentric rings which are capable of sliding axially one in relation to the other, resilient means being provided between each ring in order to bring about their relative sliding action.

According to a second embodiment of the invention, the screen is formed by a conical spring which is held in an extended state by means of the front and rear charges when the latter are next to each other.

According to other characteristics, the warhead according to the invention comprises a first pyrotechnic charge which is intended to cause the warhead to move from a contracted position into an expanded position by causing the.front charge and the rear charge to move apart in a relative manner.

The invention will be better understood by reading the following description of particular embodiments, described with reference to the attached drawings in which: Figure 1 shows a longitudinal section through a warhead according to a first embodiment of the invention; Figure 2 shows this same warhead in an expanded position; Figures 3a and 3b show the intercharge screen, on *its own, in its transportation position and active position respectively; Figure 3c is a perspective view of one of the rings of the intercharge screen.

Referring now to Figure 1, a warhead 1 according to a first embodiment of the invention comprises a casing 2, arranged in the interior of which there are two shaped charges (here concave charges), a front charge 3a and a rear charge 3b.

The warhead 1 is shown alone here. It is intended to be deployed in a munition -not shown -such as a missile, a rocket or else a bomb.

Each shaped charge comprises, in a known manner, an explosive load 4a, 4b, which is arranged in a casing 5a, 5b and to which a covering Ga, 6b is applied.

Each explosive load is initiated by means of a priming device 7a, 7b -not shown in detail here -which will also comprise a safety and armament device.

The warhead here occupies a position (called the contracted position) which is the position which it occupies during the phases of storage and flight of the munition.

The front and rear charges are then arranged axially so as to be in the vicinity of each another.

They are separated by a protective intercharge screen 8 that is formed by means of a plurality of coaxial rings (here eight rings 8a, 8b.. .Sh). The peripheral ring 8h is adjusted to the internal surface of the casing 1 and is firmly attached to the latter (for example by means of adhesion).

The intercharge screen 8 then substantially follows the profile of the covering 6b of the rear charge 3b as well as that of the rear portion of the casing 5a of the front charge 3a.

The front and rear charges are capable of being relocated in relation to the casing 2 so as to come to a stop level with a front flange 9 for the front charge 3a and a rear stop 10 for the rear charge 3b respectively.

The rear stop 10 is thus intended to cooperate with the rear portion of the casing of the rear charge 3b, whilst the front charge 3a bears a peripheral ring 11 which is intended to come to a stop at the front flange 9. The peripheral ring 11 also ensures that the front charge is guided in relation to the casing during relocation.

The front flange 9 and the rear stop 10 are firmly attached to the casing 2 of the warhead. One of these two stops will be removable (and firmly attached to, for example, a screw-in ring) in order to allow the charges to be deployed n the interior of the casing 2.

In order to ensure that the charges are immobilized during the phases of storage and flight of the warhead, the charges are connected to the casing by means of radial pins -not shown -which can be sheared off.

The relocation of the front and rear charges is controlled by means of a first pyrotechnic separating charge 12 which is arranged between the front charge 3a and the rear charge 3b and which, advantageously, will be firmly attached here to the internal ring 8a of the intercharge screen 8.

The separating charge 12 is initiated by means of classic priming means -not shown -which may comprise a safety and armament device.

Figure 2 shows this same warhead when it is located close to a target and before initiation of the charges.

The first separating charge 12 has been initiated in response to a command supplied by a proximity fuse or a target detector. The pressure of the gases which it has generated has caused the pins holding the charges in relation to the casing tO be sheared off and has brought about the relocation of the front and rear charges until they are stopped at the flange 9 and the rear stop 10 respectively.

The total length of the warhead is increased by approximately 40% in this way. Its contracted length is that (Li) of the casing 2, its expanded length is marked as L2 in Figure 2.

The protective screen 8 has a telescopic structure and moves, as a result of the charges moving apart from each other, from a position of transportation (Figure 1) into an active position (FIgure 2) in which its axial space requirement is reduced.

Such an arrangement allows the effectiveness of the screen to be improved, because it allows the various rings of the screen, which are not firmly attached to the casing 2, to move away from the rear charge 3b.

The screen, at a distance from the rear charge, thus ensures that the gases and fragments which are produced by the front charge are retained.

The telescopic screen is shown in detail in Figures 3a and 3b. Its position of transportation can be seen in Figure 3a and its active position is shown in Figure 3b. -The screen is formed of eight concentric rings 8a. . . 8h. The external ring Bh is fixed to the casing 2 of the warhead, for exanpie by means of adhesion. Each ring is mounted so as to slide in relation to the adjacent rings.

The rings arranged between the external ring 8h and the internal ring 8a have three longitudinal slots 13 evenly distributed angularly (at 120 one from the other) as well as three radial pins which are evenly distributed and arranged so as to alternate with the slots (see the perspective view of Figure 3c).

The external ring 8h only has pins because it is fixed in relation to the casing 2 of the warhead.

The internal ring 8a only has slots.

The slots 13 of any one given ring are intended to receive and guide the pins 14 which are borne by the ring that has the next greatest diameter, greater than that of the ring in consideration.

A compression spring 15 is arranged in each slot 13 and takes its bearing, on one side, on the ring and, on the other, on the pin in consideration.

The springs are positioned in such a way that all of them are compressed when the screen formed. by the set of rings is in the transportation position (Figure 3a).

The rings are held in this position by means of the front and rear shaped charges 3a and 3b which act as axial stops.

When the shaped charges move apart, the springs relax and bring the screen 8 into its active position shown in Figure 3b.

As a variant, it is possible to realize the screen 8, which is located between the charges, in the form of a compression spring with a conical winding.

Such a screen will have a longitudinal section which will *be similar to that shown in Figures 1 and 2.

However, instead of concentric rings there will be a single resilient steel band which will then be wound up around the rear portion of the front charge 3a.

This spring will be in an extended position in the position of transportation (Figure 1). The movement of the charges apart from each other will bring about its return into its position of equilibrium (not extended) which is also the active position of the screen thus formed (Figure 2).

The movement of the charges apart from each other caused by the first pyrotechnic composition 12 allows the rear charge to be protected from the effects of detonation of the front charge, even if the latter is of a considerable calibre.

The protection is improved further by the fact that the front charge has a rear portion with a truncated form.

The warhead in accordance with the invention can thus be considerably effective against concrete, this property being imparted to it as a result of the fact that the diameters of the charge are of the order of 200mm, despite the space which it requires being extremely reduced, this being achieved as a result of the telescopic screen (contracted length Li - approximately 500mm, expanded length L2 -approximately S5Qmm).

Claims

Claims 1. Warhead (1) which comprises at least two shaped charges, one front charge (3a) and one rear charge (3b), coaxially arranged one behind the other in a casing (2), the front charge and the rear charge being capable of being relocated one in relation to the other in trajectory before they are initiated, whilst both remain firmly attached to the casing, the warhead being characterised in that the front and rear charges are separated by a telescopic pro,tective screen (8) capable of moving, when the charges are moved apart, from a transportation position, in which it * substantially follows the profile of a covering (6b) of the rear charge (3b), into an active position in which its axial space requirement is reduced.
2. warhead according to claim 1, characterised in that the screen (8) is formed by a plurality of concentric rings (8a, Sb.. .Bh) which are capable of sliding axially one in relation to the other, resilient means (13) being provided between each ring in order to bring about their relative sliding action.
3. Warhead according to claim 1, characterised in that the screen is formed by a conical spring which is held in an extended state by means of the front and rear charges when the latter are next to each other.
4. warhead according to one of claims 1 to 3, characterised in that it comprises a first pyrotechnic charge (12) which is intended to cause the warhead to move from a contracted position into an expanded position by causing the front charge (3a) and the rear charge (3b) to move apart in a relative manner.C Amendments to the claims have been filed as follows Claims -1. Warhead which comprises at least two shaped charges, one front charge and one rear charge, coaxially arranged one behind the other in a casing, the front charge and the rear charge being capable of being relocated one in relation to the other in trajectory before they are initiated, whilst both remain firmly attached to the casing, the warhead being characterised in that the front atd rear charges are separated by a telescopic protective screen capable of moving, when the charges are moved apart, from a transportation position, in which it substantially follows the profile of a covering of the rear charge, into an active position in which its axial space requirement is reduced. - 2. Warhead according to claim 1, characterised in that the screen is formed by a plurality of concentric rings which are capable of sliding axially one in relation to the other, resilient means being provided between each ring in order to bring about their relative sliding action.3. Warhead according to claim 1, characterised in that the screen is formed by a conical spring which is heldin an extended state by means of the front and rear charges when the latter are next to each other.4. Warhead according to one of claims 1 to 3, characterised in that it comprises a first pyrotechnic charge which is intended to cause the warhead to move from a contracted position into an expanded position by causin the front charge and the rear charge to move apart in a relative manner.
5. Warhead, substantially as heteinbefore described with reference to, and as shown in, the accompanying drawings. -