GB2272046A - Explosive mines - Google Patents

Abstract

A mine which is designed to defeat countermeasures such as flails and ploughs. Burying of a mine 30 centimetres, say, below ground level will defeat a flail or plough, the latter of which may take off the ground surface to a depth of 15 centimetres. However the "overburden", ie the soil or material which tends to fill the space above the mine after placement, can inhibit the proper operation of the explosive charge, normally requiring a clearing charge to displace it. The present invention overcomes this problem by fitting a telescopic canister 5 to the main charge compartment 3 to produce an enclosed space above the charge. The mine is laid in a drilled (or dug) hole and the telescopic canisters pushed down to just below ground level. Negligible resistance to the explosion is thus provided between the charge and the target above. The mine may comprise tandem hollow charges. <IMAGE>

Description

MINE This invention relates to mines, that is, explosive mines for military purposes and particularly, but not exclusively, for use against tanks.

Modern mine countermeasure methods for the clearance of anti-tank (and anti-personnel) mines include mechanical methods such as flails, ploughs and rollers, and also explosive hose and fuel-air explosive (FAE) devices. These methods are extremely effective against mines laid on the surface, or buried at shallow depths, e.g.

with their upper surfaces a few centimetres below ground, since the countermeasure equipments can clear a path in front of a tank down to a depth of, typically, 15 centimetres.

Modern mine fuzes are often arranged to trigger detonation of the mine when it is attacked by a mechanical countermeasure, but these equipments, ploughs, etc., are extremely robust, and can tolerate the nearby explosive effects: such measures are therefore not effective.

Mines close to the detonation of explosive hose are usually destroyed by their sympathetic detonation.

An alternative, and more effective method of using anti-tank mines against an energy employing countermeasures, is to bury the anti-tank mines deeply, at say, 30 centimetres depth below the soil surface - thus they are untouched by the mechanical countermeasures, and may well not be detonated by explosive hose. They are also unaffected by FAE devices.

However, deep burial poses other problems in designing an anti-tank mine, in that the 'over-burden' (the soil/material above the mine) has to be removed by a clearing charge, before the main charge is detonated. This allows the proper function of the mine warhead's damage mechanism, for example, an explosively-formed projectile (EFP), which is designed to penetrate the target's bottom armour, and to cause internal damage. Removal of a considerable depth of overburden, e.g. 20 centimetres of soil (which could be frozen), requires a very energetic clearing charge, with consequential risk of damage to the mine when it is exploded, even if the mine is strengthened.

An object of the present invention is to provide a mine which overcomes the above problems.

According to the present invention, a mine adapted to be buried below ground comprises a first compartment containing an explosive charge and a second compartment adapted to exclude ground material from a space above the charge compartment when the mine is buried with the second compartment uppermost.

The second compartment is preferably of telescopic form to permit the end of the second compartment remote from the charge compartment to be positioned at ground level for a range of depths of the charge compartment. The second compartment may be in several sections which are adapted to telescope together and enclose the charge compartment.

The second compartment may be made of glass-fibre reinforced plastic.

Seals may be provided between adjacent sections to tend to exclude water or other liquid.

One embodiment of a mine in accordance with the invention will now be described, by way of example, with reference to the accompanying drawings, of which: Figure 1 is a part cross-section of a mine in operational position, ie, buried in ground to a considerable depth; and Figures 2(a) (b) and (c) are diagrams of the effect of a plough countermeasure on such a buried mine.

Referring to Figure 1, the mine comprises, basically a first compartment 1 containing the main warhead filling 3, and a second compartment 5, which is shown in three sections 5(a), 5(b) and 5(c).

Compartment 1, ie the charge container, is made of metal or plastic and is closed at the top by a liner 7 of metal in known manner. A fuze mechanism 9 is incorporated in the bottom of the compartment 1, the fuze being responsive to one or more influences produced by the presence of a target to detonate the main charge 3.

The upper compartment sections 5 a, b and c are of cylindrical form, each closed at its upper end to form a series of inverted cups. The cylinders are of increasing diameter from bottom to top so that they can close up telescopically. Stops or anchorages in the top and bottom of the walls limit the maximum extent of the composite second compartment and also permit extension by pulling on a handle 11 fitted to the upper cylinder 5c.

The axial extent of one section (5(b)) may be greater than that of the next lower section (5(a)) so that a minimum space (in 5b) remains even when the arrangement is fully closed up.

In use, the mine with the attached cylinder sections, is laid in a pre-drilled (or dug) hole, and the cylinders are pushed down so that the top of the upper cylinder (a) is approximately flush with, or slightly below the level of, the surrounding ground. A thin scattering of soil/camouflage material can then be put on top of the upper cylinder.

The mine is armed, in the usual manner, before placing it into the hole; this can be done manually, or automatically if a mine laying equipment is employed. The mine laying equipment can also be arranged to push down the tube assembly automatically, using for example, a lightweight roller, and to cover the mine by dragging a chain across the surface of the ground as the layer passes over the laid mine.

The primary function of the arrangement of cylinders is to provide a substantially clear path for the warhead's operation, facilitating the proper formation and acceleration of the EFP fragment or jet. The closed ends of the cylinders do not present any significant resistance to its passage - nor does the thin layer of soil/camouflage.

In operation against mechanical mine countermeasures, the upper cylinder 5(c) is arranged to have a length which approximates to the depth to which the countermeasure, e.g. a plough or flail, would push aside or disturb the soil, e.g. of the order of 15 centimetres (dependent upon the hardness of the ground, and the type of equipment used by the enemy). The anchorage of the upper cylinder to the one below is arranged to break-off easily when subjected to force at right angles to the axis. Thus when contacted by the countermeasure, or by the soil being pushed along in front of it, the upper cylinder breaks-off, but leaves the lower cylinder(s) and the mine undisturbed.

The presence of the closed-end of the lower-cylinder maintains a clear volume above the mine and prevents loose soil/debris from obstructing the warhead's operating path. The mine is then able to be detonated by its influence fuze in the normal manner as the target vehicle passes over it (see Figure 2).

The scheme can be applied to new designs of mines, ab initio: alternatively it can be arranged to be fitted to existing designs of mines, to allow them to be deep buried.

Mines which incorporate a penetrating warhead usually incorporate a small clearing charge, e.g. black powder, to remove the overburden slightly before initiation of the main charge. Use of the present invention renders this unnecessary, thus simplifying the design of the explosive initiation mechanism.

Against future tanks, which may utilize improved bottom armour, e.g. composite energy-absorbing materials, or reactive armour, the present invention would facilitate the incorporation of a tandem warhead, with an upper charge 15 mounted, for example, on the lower cylindrical tube (shown dotted in Figure 1).

The telescopic cylinders can be arranged to be sealed using, for example, O-rings. This will permit the mine's warhead to function properly even when the mine is immersed in shallow water (0.5 - 1.0m is a common requirement). Such a capability would also permit the mine to be used for example, as a river mine or beach mine; in this case, only the lower cylinder need be used, thus ensuring that negative buoyancy is retained.

Claims (7)

1. A mine adapted to be buried below ground and comprising a first compartment containing an explosive charge and a second compartment adapted to exclude ground material from a space above the charge compartment when the mine is buried with the second compartment uppermost.

2. A mine acording to Claim 1, wherein said second compartment is of telescopic form to permit the end of the second compartment remote from the charge compartment to be positioned at ground level for a range of depths of the charge compartment.

3. A mine according to Claim 2, wherein said second compartment is in several sections which are adapted to telescope together and enclose the charge compartment.

4. A mine according to any preceding claim, wherein said second compartment is made of non-metallic material.

5. A mine according to Claim 4, wherein said second compartment is made of glass fibre reinforced plastic.

6. A mine according to Claim 2 or Claim 3, wherein said end of said second compartment remote from the charge compartment incorporates a handle for extending the second compartment on positioning the mine at the bottom of a hole.

7. A mine substantially as hereinbefore described with reference to the accompanying drawings.

7. A mine according to Claim 3, wherein seals are provided between adjacent ones of said sections to tend to exclude water or other liquid.

8. A mine substantially as hereinbefore described with reference to the accompanying drawings.

Amendments to the claims have been filed as follows 1. A mine adapted to be buried below ground and comprising a first compartment containing an explosive charge and a second compartment adapted to exclude ground material from a space above the charge compartment when the mine is buried with the second compartment uppermost, said second compartment being telescopically coupled to said charge compartment to permit the end of the second compartment remote from the charge compartment to be positioned at ground level for a range of depths of the charge compartment.

2. A mine according to Claim 1, wherein said second compartment is in several sections which are adapted to telescope together and enclose the charge compartment.

3. A mine according to Claim 1 or Claim 2, wherein said second compartment is made of non-metallic material.

4. A mine according to Claim 3, wherein said second compartment is made of glass fibre reinforced plastic.

5. A mine according to Claim 1 or Claim 2, wherein said end of said second compartment remote from the charge compartment incorporates a handle for extending the second compartment on positioning the mine at the bottom of a hole.

.. . .t 6. A minè~according to Claim 2, wherein seals are provided between adjacent ones of said sections to tend to exclude water or other liquid.