GB2234203A

GB2234203A - Explosive devices

Info

Publication number: GB2234203A
Application number: GB8715876A
Authority: GB
Inventors: Derek Beattie; Norman George Taylor; Darrel Steven Wall; Phillip Ernest Gardiner
Original assignee: British Aerospace PLC
Current assignee: BAE Systems PLC
Priority date: 1986-07-03
Filing date: 1987-07-03
Publication date: 1991-01-30
Anticipated expiration: 2007-07-03
Also published as: GB8715876D0; GB2234203B; SE8702854D0

Abstract

An underwater weapon 1 for mine countermeasures comprises a shaped charge 2 which is attached to a target mine (26) by means of an explosive attachment unit 10, e.g. a nail gun. Contact sensors 5 and hydrostatic transducer 7 in conjunction with safety and arming unit 6 make the weapon safe until it is underwater in contact with a mine. A transducer 9 enables the weapon to be armed and detonated by remote control. A multi-facetted portion 8 enables the weapon to be gripped and manipulated by remote control. <IMAGE>

Description

EXPLOSIVE DEVICES This invention relates to explosive devices and in particular, but not exclusively, to mine countermeasures, e.g. mine disposal.

According to this invention an explosive device comprises an explosive charge and explosively actuated attachment means arranged to be driven into secure engagement with an object thereby to secure the charge to the object.

Preferably the explosively actuated attachment means comprises a nail gun arranged to connect the explosive charge to the object.

Preferably the explosive charge is a shaped charge profiled to direct explosive energy in a predetermined direction and the explosive device further includes a spacing portion downstream of the shaped charge in the predetermined direction to assist the formation of a jet of particles upon detonation of the shaped charge.

The explosive charge preferably includes a metal lining which fragments into a jet of high speed particles upon detonation of the charge. Preferably the spacing portion is evacuated to assist the formation of the jet of particles upon detonation of the shaped charge.

Preferably the explosive device includes command link means for remote actuation of the attachment means and detonation of the explosive charge. Advantageously the explosive device includes a safety and arming unit comprising a hydrostatic transducer and contact sensors to prevent the attachment means being fired until the explosive device is both underwater and in contact with an object. The safety and arming unit preferably prevents the explosive charge being armed until the explosive device is both underwater and in contact with an object and also has been attached to the object by the attachment means.

Preferably the explosive device includes a timing device adapted automatically to disarm and make safe the main charge if the main charge is not detonated within a pre-set time.

A particular example of an explosive device in accordance with this invention will now be described with reference to the accompanying drawings; in which: Figure 1 is a perspective view of a mine disposal weapon; and, Figures 2a to 2d are schematic diagrams of the mine disposal weapon of Figure 1 and a remotely operated vehicle and show the weapon being transported, attached to a mine and armed by remote signal, respectively.

Referring to Figure 1 the mine disposal weapon comprises a cylindrical weapon casing 1, for housing a shaped charge warhead 2 which is arranged to direct its explosive energy towards the lower end of the casing 1.

The warhead is typically 7.5 cm in diameter and 10 cm long and contains a conical metal lining 3. The metal lining 3 fragments into a jet of high speed metal particles upon detonation of the charge. Beneath the charge 2 is a spacing region 4 which is evacuated to enable the jet to form effectively before it begins to penetrate the casing of the mine. Safety and arming unit 6 is positioned behind the charge 2 and enables the weapon to be handled and stored in safety. The unit 6 is responsive to signals from a hydrostatic sensor 7 and a pair of contact detection sensors 5, only one of which is shown, which are attached to the lower end of the casing 1 at diametrically opposed locations.A facetted portion 8 at the closed end of the weapon casing enables the entire weapon to be gripped and manipulated by the remotely operated vehicle and an acoustic receiver 9 is placed in the end of the facetted portion to receive a remote detonation signal. Along the side of casing 1 is an explosive attachment device 10 for attaching the weapon to the mine to be destroyed. The explosive attachment device comprises an elongate fairing containing a firing mechanism 11 for detonating a percussion cap 12 the explosive force of wHich drives a toughened nail 13 forwardly through an aperture 14 in the end of the attachment device. The toughened nail includes a washer 15 to prevent it from completely penetrating the surface of a target. Referring to Figures 2a to 2d the mine disposal weapon of Figure 1 is intended to be located and operated using a remotely operated vehicle (R.O.V.).The R.O.V. comprises a body 20 and propulsion system 21. A remotely operated arm 22 is mounted on one end of the R.O.V. and is used for gripping the underwater weapon by means of a claw 23.

The R.O.V. is guided and the weapon manipulated by means of a television sensor 24 or high resolution sonar (not shown) mounted on the R.O.V.

Operation of the device is now described with reference to Figures 1 and 2a to 2d. In Figure 2a the underwater weapon is carried to a target area by the remotely operated vehicle 20 which carries the weapon using the claw 23 of manipulator arm 22 to grip facets 8 on the weapon. Control signals are transmitted between the remotely operated vehicle and the disposal weapon via a command line 25 connected to a socket 16 on the mine disposal weapon. When the remotely operated vehicle has reached its target area the mine to be disposed of is inspected with onboard sensors. Figure 2a shows how the R.O,V. is positioned to within manipulator reach of the mine. In Figure 2b the manipulator arm 22, with weapon is extended and the R.O.V, is moved towards mine 26 until contact is made with the mine casing and signalled by sensors 5.Although an articulated manipulator arm 22 is shown being extended and folded in Figures 2a to 2d a limited function manipulator arm could be used which is fixed and has no extension capability. When the operator receives a signal indicating that successful contact has been made with the mine the operator triggers the explosive fastening device 10 by a signal via the R.O.V.

command line 25 (Figure 2b). Alternatively the fastening device can be arranged to detonate automatically upon contact of the sensors 5 with the mine casing. Upon receipt of the correct signal the firing mechanism 11 detonates a percussion cap 12. The force of the explosion from the percussion cap drives the toughened nail 13 forwardly through aperture 14 to penetrate the casing of the mine to be destroyed. As the nail 13 penetrates the mine casing a friction weld is produced which holds the weapon securely in place on the mine.

When the weapon is attached to the mine the R.O.V. is withdrawn and recovered (Figure 2c). The weapon is armed and detonated remotely by an acoustic signal 27 which is detected by acoustic receiver 9 (Figure 2d).

The hydrostatic sensor 7 and contact detection sensors 5 ensure that the weapon can be stored and handled safely and cannot be armed accidentally during handling and that arming only occurs when the weapon is submerged. As a further safety feature a timer 17 is used to generate a window during which the acoustic signal must be received. If the signal is not received within the time limits set by the timer then the weapon disarms itself and remains safe even if the acoustic signal is received later. When the signal is received, during the window, the shaped charge warhead is detonated to destroy the mine 26.

Claims

1. An explosive device comprising an explosive charge and explosively actuated attachment means arranged to be driven into secure engagement with an object thereby to secure the charge to the object.

2. An explosive device according to claim 1, in which the attachment means comprises a nail gun.

3. An explosive device according to claim 1 or 2, in which the explosive charge is a shaped charge profiled to direct explosive energy in a predetermined direction and the explosive device further includes a spacing portion downstream of the shaped charge in the predetermined direction to assist the formation of a jet of particles upon detonation of the shaped charge.

4. An explosive device according to claim 3, comprising a metal lining which fragments into a jet of high speed particles upon detonation of the charge.

5. An explosive device according to claim 3 or 4, in which the spacing portion is evacuated to assist formation of the jet of particles.

6. An explosive device according to any preceding claim, which includes command link means for remote actuation of the attachment means and detonation of the explosive charge.

7. An explosive device according to any preceding claim, which includes a safety and arming unit comprising a hydrostatic transducer and contact sensors.

8. An explosive device according to any preceding claim, which includes a timing device adapted automatically to disarm and make safe the main charge if the main charge is not detonated within a pre-set time.

9. An explosive device substantially as hereinbefore described with reference to the accompanying drawings.