DE69810877T2 - Ammunition to clear mines - Google Patents

Abstract

The shell comprises a projectile (1) launched by a propulsive charge and containing a disperser (7) for one or more magnetic field generators (8) in the form of magnetic sub-projectiles.

Description

The technical field of the invention relates to ammunition for clearing mines, in particular landmines.

The mine clearing munitions make it possible to clear a passage in a minefield at a safe distance.

Depending on their size and performance, they are operated either by a person or by a vehicle.

The known mine-clearing munitions generally contain an explosive charge that is detonated near the mines in order to cause them to detonate.

For example, patent US4776255 discloses a self-propelled projectile that deploys a detonation fuse along its trajectory. The fuse is ignited when it comes into contact with the ground.

There are also known munitions for clearing mines, in which the explosive is detonated at a distance from the ground. It is the pressure wave of the explosion that then causes the ignition of the mines.

These mine-clearing munitions are ineffective against new generation anti-tank mines whose fuses are designed to withstand the shock caused by the detonation of an explosive charge.

The new generation of anti-tank mines are generally equipped with a fuse with a magnetic sensor, which enables them to detect the approach of the large ferromagnetic mass formed by a tank or vehicle.

The known mine-clearing systems which allow such mines to be triggered out of range comprise an electromagnetic generator which is firmly connected to a vehicle and which projects a magnetic signature close to that of a tank towards the front of the vehicle.

The patent FR2701105 discloses such a system for clearing mines.

However, such systems are expensive, consume a lot of energy and therefore cannot equip all combat vehicles.

In addition, they can only detonate mines towards the front of the vehicle and at a relatively reduced distance (in the order of 3 m).

From the patents EP757224 and DE3528338, munitions are known that carry or scatter microwave generators. Such generators are complex and expensive to manufacture, and they are particularly intended to neutralize radar or fire control systems.

Patent US5192827 proposes a projectile that generates an electromagnetic pulse, in particular microwave or radio frequency, in the vicinity of a target. It uses a capacitor that is charged with electricity before firing. Such a projectile is also complicated to use.

Patent DE2455769 discloses a system for destroying landmines using a conductive net connected to an electrical generator. The net can possibly be scattered over short distances by a powder rocket. The use of such a projectile is also complicated, as it requires resorting to an electrical generator and establishing electrical connections.

Finally, patent US4562789 shows a system for clearing land mines consisting of a torpedo carrying permanent magnets in the form of rotating disks driven by servomotors. The shape of the field is modulated by playing with the relative speeds of rotation of the various disks. Such a device is complex and bulky and is completely unsuitable for a land mine clearing operation.

The object of the invention is to propose a mine-clearing ammunition which makes it possible to eliminate such disadvantages.

The ammunition according to the invention is therefore of a simple design and inexpensive, since it does not use electrical energy on board or in a delocalized manner. It can therefore be used as equipment on all combat vehicles to enable them to ensure their self-protection against mines.

It can also be designed to be light enough to be used by infantrymen.

Finally, it is effective against all new generation mines equipped with a magnetic sensor and against those mine clearing munitions that use explosives, which are ineffective.

The subject matter of the invention is therefore an ammunition for clearing mines, in particular landmines, which comprises at least one projectile fired by means of a propellant charge and contains at least one magnetic field generator, the ammunition being characterized in that the projectile comprises means for scattering which make it possible to release the magnetic field generator(s), which consist of magnetic subprojectiles, on the flight path.

According to a special embodiment, the sub-projectiles can be spherical or have two conical ends.

According to a particular embodiment, the sub-projectiles can have a core made of magnetic material that is not covered by a plastic casing.

The material of the core or the magnetic sub-projectile can have a coercive field of greater than 40,000 A/m and a remanence of more than 0.8 Tesla.

Advantageously, the material of the core or the magnetic part of the bullet is selected from the following materials: AlNiCo V, SmCo5, neodymium.

According to one variant, the plastic of the shell surrounding the core is colored and/or fluorescent.

According to a further embodiment, the projectile comprises at least one housing or container which contains the sub-projectiles, the means for dispersion consisting of a scattering charge which is arranged at the level of the axis of the housing or container.

Advantageously, the ammunition may comprise at least two projectiles arranged in a launch tube fixedly connected to a launch platform, the tube containing an ejection charge.

The invention will be more clearly understood from reading the following description of particular embodiments, the description refers to the attached illustrations in which:

- Fig. 1 shows a projectile of a mine clearing ammunition according to a first embodiment of the invention,

- Fig. 2 shows a projectile of a mine clearing ammunition according to a second embodiment of the invention,

- Fig. 3 shows a special embodiment of a magnetic field generating sub-projectile in section,

- Fig. 4 shows a mine clearing ammunition according to a third embodiment of the invention in longitudinal section, the section being made according to the fixed plane BB in Fig. 5,

- Fig. 5 is a cross-sectional view of this ammunition, the section being taken along the plane AA in Fig. 4,

- Fig. 6a and 6b are diagrams showing two operating phases of an ammunition according to the invention,

- Fig. 7 is a sectional view of another particular embodiment of a magnetic field generating sub-projectile.

Referring to Fig. 1, a mine clearing ammunition according to a first embodiment of the invention comprises a propellant charge (not shown) and a projectile 1.

The projectile here is a projectile for artillery or mortars and its propellant charge is contained, for example, in a casing or a cartridge.

In the classic way, the projectile 1 has a body 2, to which a projectile tip 3 or a projectile base 4 is attached by threads or rivets.

A belt 5 for sealing the propellant gases is wrapped around a rear portion of the body 2 and allows the projectile to be fired from a weapon system (not shown), such as a cannon or a mortar.

The projectile tip 3 carries a programmable, mechanical or electronic time fuse 6 at its front end. This fuse is intended to ignite a pyrotechnic gas-producing mixture 7.

The body 2 of the projectile contains magnetic field generating means 8, which are described below, as well as a pressure piston 19.

The means for generating the magnetic field are formed by magnetic sub-projectiles in the form of spheres (approximately 140 spheres of 12 mm diameter).

Fig. 3 shows such a partial projectile 9 in section. It has a parallelepiped core 10 (here, for example, cubic) made of a magnetic material that generates a magnetic field of high intensity, the core being encased in a shell 11 made of plastic (for example, a deformable polymer such as rubber).

Each ball has a diameter of 10 to 20 mm, the side length of the cube is between 8 mm and 12 mm.

The magnetic material is selected such that it has a coercive field of greater than 40,000 A/m and a remanence of more than 0.8 Tesla.

For example, sintered alloys can be selected as the magnetic material, which are usually used to manufacture the permanent magnets of DC motors:

Al-Ni-Co V (aluminium/nickel/cobalt) whose coercive field is 52000 A/m and remanence is 1.25 T,

Sm-Co5 (samarium/cobalt) - coercive field: 440,000 A/m, remanence 0.9 T,

Neodymium - coercive field: 689700 A/m, remanence: 1.3 T.

The function of the casing 11 is to dampen the shocks received by the core, both when the projectile is fired and when the sub-projectiles are scattered. Due to its deformability, it also allows the sub-projectiles to be arranged without play in the body of the projectile, with the sub-projectiles now being held in a slightly compressed manner between the projectile base 4 and the piston 19.

The casing can advantageously be made of a colored or phosphorescent plastic, thus ensuring a marking of the area cleared of mines. The functionality of this ammunition is as follows.

After determining the area to be cleared of mines and estimating its distance, the Time fuse 6 is programmed (manually or with a programming system not shown) by entering into it the data corresponding to the moment at which dispersion is to be initiated from the moment of firing. This moment depends on the characteristics of the firing (velocities and firing angles) and is indicated by a firing table.

A launch platform fires the projectile 1 towards the zone to be cleared of mines. At the end of the programmed time interval, the detonator 6 ignites the scattering means formed by the pyrotechnic charge 7. The pressure of the gases produced drives the piston 19, which exerts pressure on the base of the projectile 4 by means of the balls 9 forming the field-generating means 8.

The means of joining the base of the projectile and the body 2 is sheared off and the balls 9 are scattered over the area to be cleared of mines. The speeds of the various balls are variable in magnitude and direction and their respective positioning is also variable. This results in a global magnetic field generated by the entirety of the balls, which is variable in direction. The level of the field is sufficient to trigger the majority of mines with a passive fuse. The variability of the field also makes it difficult to design a hardened mine fuse for this type of baiting.

Fig. 2 shows another embodiment of a mine clearing ammunition according to the invention.

This form differs from the previous one in that the body 2 of the projectile 1 does not contain a pack of balls, but a transport container 12 formed by a metal shell 13 closed at each end by a cover 14a, 14b.

The cover 14b carries a delay igniter 15, which is connected to the igniter 6 by a connection 16.

The igniter 15 is connected to a scattering explosive charge 17, which is arranged in a coaxial casing in the transport container 12. The scattering charge is, for example, a charge that combines aluminum and potassium perchlorate.

The transport container 12 contains a magnetic field generator 8, which is formed by a pack of magnetic balls as previously described.

The operation of this embodiment is as follows. When the projectile 1 is located above the zone to be cleared of mines, the igniter 6 causes, on the one hand, the ignition of the pyrotechnic charge 7 and, on the other hand (by means of the connection 16), that of the pyrotechnic delay of the delay igniter 15.

The pressure of the gases drives the piston 19, which ejects the projectile base 4 and the transport container 12. This now follows its own trajectory to the ground.

Its orientation in relation to the ground and its speed can be corrected by classic means used in partial munitions, not shown here: brake wings, parachute.

When the pyrotechnic delay of the igniter 15 is used up, the scattering charge 17 is ignited and causes the transport container 12 to burst and the magnetic balls to scatter.

The advantage of this embodiment over the previous one is that it allows the balls to be released at a shorter distance from the ground (for example, in the order of 2 to 5 m), which results in less dispersion of the balls in space and greater effectiveness in clearing mines.

As a variant, it is of course possible to arrange several different transport containers 12 inside the body of the projectile 1. Each transport container contains magnetic balls and a scattering explosive device ignited by a pyrotechnic delay. This results in a better spatial distribution of the balls.

Fig. 4 shows an ammunition according to a third embodiment of the invention:

This ammunition 101 comprises a case 102 which, in the region of a rear portion 102a, has a projection 103 which carries a radial pin 104 which enables the ammunition to be attached by a bayonet mounting to a structure fixed to it, such as a Vehicle or fixed structure connected launcher (not shown) allowed.

The sleeve 102 is closed at its front section by a cover 120 which is firmly connected to the sleeve by at least one radial pin 121.

The sleeve 102 has a rear collar 102b which is pressed between a shoulder of the extension 103 and a nut 105 screwed onto the extension.

The extension 103 carries an electric igniter 106 which is fixed to a support 107 glued to the extension 103. The electric wires of the igniter 106 are connected on the one hand to an axial contact 108 and on the other hand to the extension 103, the axial contact being electrically insulated from the extension. The support 107 contains a pyrotechnic ejection charge 109 which is formed, for example, by a propellant powder or an ignition powder.

The casing 102 also contains a piston 110 on which a package of two mine-clearing projectiles 111a, 111b are arranged. The piston 110 has a diameter smaller than that of the casing 102 and rests on a counterbore at the rear of the projectile 111a.

The casing 102 represents, for example, a launch tube for the projectiles 111, with the ejection charge 109 intended to generate gases that act on the piston 110, which expels the projectiles from the casing.

Each projectile 111 is formed by a cylindrical housing 112, for example made of aluminum, and is closed by a screwed bottom 114 and a screwed cover 113.

The base 114 carries an axial housing which accommodates an ignition plug 116 containing a pyrotechnic mixture for delaying the ignition.

A scatter explosive device 117 is provided in a casing 118 made of plastic material coaxially in the housing 112.

The housing also contains a magnet generator formed by a pack of balls of the type previously described (approximately 70 balls of 12 mm diameter per housing).

The bottom 114 of each projectile 111 is arranged embedded with respect to the rear end of the housing. Such an arrangement makes it possible to establish, on the one hand, a chamber 122a between the rear projectile 111a and the piston 110 and, on the other hand, a chamber 122b between the two projectiles 111a and 111b.

The casing of each projectile comprises two radial notches 123 formed in its rear portion (see Fig. 5) and the casing 112a of the rear projectile 111a also comprises two longitudinal grooves 119 extending along two generatrices.

The notches 123 of the rear projectile allow a portion of the propellant gases generated by the ejection charge 109 to flow towards the chamber 122a and the delay igniter of the rear projectile 111a.

The longitudinal grooves 119 also allow a portion of the propellant gases to flow to the chamber 122b separating the two projectiles 111a and 111b, via the notches 123 arranged in the housing 112b of the front projectile 111b.

The propellant gases thus also ensure the ignition of the pyrotechnic delay mixtures of the two projectiles, whereby these mixtures ensure the ignition of the scatter charges 117 on the flight path.

These grooves 119 are dimensioned to allow sufficient gas to flow through to ignite the delay and to avoid excessive pressure between the two projectiles, which would slow down the rear projectile.

The functioning of such ammunition is now described with reference to Figs. 6a and 6b.

The ammunition case 102 is attached to a launcher 124 that is firmly connected to a vehicle or structure 125.

When the ammunition is fired, the ejection charge is ignited, and causes the lid 120 to open, the delays 116 to fire and the two projectiles 111a, 111b to be expelled.

At the end of the combustion of the pyrotechnic delays of each projectile, the scatter charges 117 are ignited (Fig. 6a), and they cause the scattering of the magnetic balls (Fig. 6b), which cause the detonation of the mines 126.

The values of the various delays are played with to ensure the ignition of each projectile in the area of a desired point on the ballistic trajectory.

For example, an ammunition can be produced in which the first projectile 111a is fired at a distance D1 from the launcher of the order of 15 m and the second projectile 111b is fired at a distance D2 from the launcher of the order of 40 m.

For each projectile, the heights H1 and H2 with respect to the ground are almost equal and close to 3 m.

The balls are now spread over the ground over an area of approximately 200 m².

A vehicle equipped with such a mine-clearing ammunition launcher can easily clear passages of approximately 10 m wide and 20 m long.

The launcher and the ammunition are light and inexpensive components that can be fitted to any type of vehicle, from tanks to light infantry vehicles. Launchers suitable for these ammunitions are already in service on numerous vehicles and enable the delivery of smoke generator ammunition or grenades for close defence. The mine-clearing ammunition according to the invention thus makes it possible to equip these vehicles easily and at minimal cost with a rapid mine-clearing capability that is more effective than pyrotechnic mine detectors even against new generation mines.

Fig. 7 shows another embodiment of a magnetic submunition 9.

This partial ammunition differs from that in Fig. 3 in that the core 10 is a rectangular parallelepiped and the casing 11 is formed from a cylindrical central part 11a to which two conical ends 11b and 11c are connected.

The axis 19 of the conical ends and of the cylindrical part of the shell 11 is perpendicular to the direction 20 of a large length 21 of the core 10.

Thus, the north (N) and south pole (S) of the magnet formed by the core 10 are arranged on either side of the axis 19 of the shell 11.

Such partial projectiles are provided in a projectile as described with reference to Fig. 1, 2 or 4, with their axes 19 running completely parallel to one another and parallel to the axis of the projectile carrier (1 or 111).

The particular aerodynamic structure of this sub-projectile favors its rotation about its axis 19 in relation to the rotations about other axes.

The rotation around the axis 19 results in a periodic change in the orientation of the magnetic field generated by each core 10. This improves the efficiency of mine clearance.

As a variant, it is of course possible to give the sub-projectiles other shapes, for example to define a sub-projectile comprising two conical ends which join together in the region of their large bases (a projectile according to Fig. 7 without the cylindrical part 11a).

Partial bullets made of magnetic material and without a plastic cover can also be defined.

Claims (9)

1. Ammunition for clearing mines, in particular landmines, comprising at least one projectile (1, 111a, 111b) fired by means of a propellant charge and containing at least one magnetic field generator (8), the ammunition being characterized in that the projectile (1, 111a, 111b) comprises means for scattering (7, 17, 117) which make it possible to release the magnetic field generator(s) consisting of magnetic partial projectiles (9) on the flight path. 2. Ammunition for clearing mines according to claim 1, characterized in that the partial projectiles (9) are spherical. 3. Ammunition for clearing mines according to claim 1, characterized in that the partial projectiles (9) have two conical ends. 4. Ammunition for clearing mines according to one of claims 1 to 3, characterized in that the partial projectiles (9) have a core (10) made of magnetic material, encased in a plastic casing (11). 5. Ammunition for clearing mines according to one of claims 1 to 4, characterized in that the material of the core (10) or of the magnetic sub-projectile (9) has a coercive field greater than 40,000 A/m and a remanence of more than 0.8 Tesla. 6. Ammunition for clearing mines according to claim 5, characterized in that the material of the core or the magnetic sub-projectile is selected from the following materials: AlNiCo V, SmCo5, neodymium. 7. Ammunition for clearing mines according to one of claims 4 to 6, characterized in that the plastic of the casing (11) is colored and/or fluorescent. 8. Ammunition for clearing mines according to one of claims 1 to 7, characterized in that the projectile comprises at least one housing or container (12, 112) which contains the partial projectiles (9), the means for dispersion consisting of a scattering charge (17, 117) which is arranged at the level of the axis of the housing or container. 9. Ammunition according to one of claims 1 to 8, characterized in that it comprises at least two projectiles (111a, 111b) arranged in a launch tube (102) firmly connected to a launch platform, the tube containing an ejection charge (109).