GB2204668A

GB2204668A - Explosion ignition systems

Info

Publication number: GB2204668A
Application number: GB08415731A
Authority: GB
Inventors: Ralph Hilary Bagnall-Wild
Original assignee: Thales Optronics Ltd
Current assignee: Thales Optronics Ltd
Priority date: 1983-07-16
Filing date: 1984-06-20
Publication date: 1988-11-16
Also published as: DE3426062A1; FR2620813A1; IT1205408B; GB2204668B; IT8467707A0

Description

EXPLOSION IGNITION SYSTEMS This invention relates to explosive projectiles incorporating a detonating mechanism and to explosion ignition systems therefor.

A known form of detonating mechanism comprises a proximity fuse which is carried by the projectile and operates when the projectile is close to a substantial object. This fuse however suffers from the disadvantage that where the intended projectile target is on or close to the ground and the trajectory of the projectile is relatively close to the ground, there is a risk of premature detonation arising from the projectile passing a substantial object en route for the intended target.

Another known detonating mechanism which is carried by the projectile operates on the basis of a time delay fuse but this mechanism suffers from the disadvantage that the time delay fuse requires to be set to the intended time of flight of the projectile prior to the projectile being loaded into the projectile launcher. At the moment of loading the required time of flight information is seldom available.

Another known form of detonating mechanism which is carried by the projectile is an inertia-operated detonator cap which depends upon a reduction in projectile acceleration for operation. This type of device suffers from the disadvantage that it requires the projectile to be decelerating either because it is at the end of its trajectory or because it has impinged upon a target.

it is an object of the present invention to provide an improved form of projectile carried detonating mechanism and an explosion ignition system therefor which obviates and mitigates the foregoing disadvantages.

According to the present invention there is provided an explosive projectile incorporating a detonating mechanism, said mechanism comprising a radiation detector operable on receipt of a predetermined radiation signal to effect detonation of the projectile, said detector being protected during storage of the projectile by a radiation non-transmissive shield frangibly secured to the projectile for automatic release from the projectile during launching of the projectile.

Further according to the present invention there is provided an explosion system for an explosive projectile according to the last preceding paragraph which system comprises a fire control system adapted to determine the time of flight of a projectile to an intended target, timer means, and means for detecting projectile ejection from a projectile launcher, said detecting means being operable to cause said timer means to count through a time interval equal to the computed time of flight provided by said fire control computer and on expiry thereof to provide a control signal, and a radiation transmitter device operable on receipt of a said control signal from said timer means to launch a radiation signal towards said target to effect detonation of a said projectile.

It will be appreciated that by virtue of the present invention the explosive projectile will be detonated on expiry of the time of flight time interval computed by the fire control computer and accordingly premature detonation is obviated, pre-setting of a timer within the projectile is obviated, and detonation is rendered independent of projectile acceleration.

Preferably the detonation system of the explosive projectile according to the present invention also comprises an inertia fuse so that should a radiation detonation signal fail to be received by the projectile, detonation of the projectile would occur automatically as a result of projectile deceleration.

An embodiment of the present invention will now be described by way of example with reference to the accompanying drawings in which: Fig. 1 schematically illustrates the projectile and its detonation system; Fig. 2 is a detail of the projectile of Fig. 1; and Fig. 3 schematically illustrates an explosion system for the projectile of Fig. 1.

As is shown in Fig. 1 a projectile 10 incorporates a detonating system 11 comprising a detonating cap 12 which is operable by an inertia fuse or striker 13.

Additionally system 11 comprises an igniter 14 which is electrically operated via amplifier 15 from a radiation detector 16. Components 15 and 16 are conveniently battery operated by means of battery 17 and ON/OFF switch 18 which is normally in the OFF condition but which is switched to the ON condition by acceleration forces and spin arising when the projectile is launched from the launcher.

Detector 16 is located in a housing 19 forming part of the base of the projectile 10, the housing 19 incorporating a shield or cap 20 covering the detector 16 from receipt of unwanted radiation, the cap 20 being frangibly secured at 20A to the housing 19 in such a manner that the gas pressure incident on the base of the projectile 10 during launching of the projectile 10 from its launcher causes rupture of the frangible mounting with subsequent release of the cap 20 from the housing 19 after the projectile 10 has emerged from the launcher and is free of the propulsion gas pressure, as is indicated in Fig. 2.

In the explosion system 30 shown in Fig. 3 a fire computer 31 which effects control of the projectile launcher (not shown) is arranged to compute the expected time of flight of the projectile to an intended target (in a manner which is known per se) and to deliver this data along line 32 to a timer device 33.

The timer device 33 is arranged to count through the time interval identified by computer 31 from a point in time identified by a detector mechanism 34 associated with the projectile launcher and operable on ejection of the projectile from that launcher. When the timer device 33 has counted through the time interval equal to the time of flight of the projectile, device 33 issues a control signal to a radiation emitter device 35 which outputs a radiation signal directed towards the intended target, the radiation signal having a sufficiently large beam spread to impinge also on the detector 16 of the projectile 10 when the projectile 10 is at or near the intended target.

By way of example detector mechanism 34 may be arranged to operate by means of the infra red radiation emitted by the projectile at launch. Detector 16 may conveniently be sensitive to optical radiation of a particular wavelength for example that provided by a laser. It will be appreciated accordingly that radiation emitter device 35 may conveniently incorporate a dual purpose laser functioning alternsstively for the detonation system control in which case the laser beam is diverged by a diverging lens or as a rangefinder.

Claims

1. An explosive projectile incorporating a detonating mechanism, said mechanism comprising a radiation detector operable on receipt of a predetermined radiation signal to effect detonation of the projectile, said detector being protected during storage of the projectile by a radiation non-transmissive shield frangibly secured to the projectile for automatic release from the projectile during launching of the projectile.

2. An explosion system substantiallç as hereinbefore described with reference to the accompanying drawing.

2. A projectile as claimed in claim 1, wherein said detonating mechanism forms part of a detonating system having an inertia-operable fuse.

3. A projectile as claimed in either preceding claim, wherein said detector is electrically enabled so as to be sensitive to a radiation signal by an inertia-operable switch electrically connected between the detector and an electrical power supply, said switch being moved to an ON condition by the inertia forces arising during launch of the projectile.

4. A projectile as claimed in any preceding claim, wherein said detector is sensitive to a laser beam radiation signal.

5. An explosion system for a projectile as claimed in any preceding claim, said system comprising a fire control computer adapted to determine the time of flight of a projectile to an intended target, timer means, and means for detecting projectile ejection from a projectile launcher, said detecting means being operable to cause said timer means to count through a time interval equal to the computed time of flight provided by said fire control computer and on expiry thereof to provide a control signal, and a radiation transmitter device operable on receipt of a said control signal from said timer means to launch a radiation signal towards said target to effect detonation of a said projectile.

6. An explosion system as claimed in claim 5, wherein said radiation transmitter comprises a laser.

7. An explosion system as claimed in claim 6, wherein said laser is dual purpose and also forms part of a laser rangefinder.

8. An explosive projectile and an explosion system there for substantially as hereinbefore described with reference to the accompanying drawing.

Amendments to the claims have been filed as follows CLAIMS 1. An explosion system for a projectile having a detonating mechanism including a radiation detector housed at the base of the projectile, said system comprising a laser rangefinder for determining the range of an intended target, a fire control computer adapted to determine the time of flight of a projectile from a projectile launcher to said target, means for detecting projectile ejection from the projectile launcher, timer means, said detecting means being operable to cause said timer means to count through a time interval equal to the computed time of flight provided by said fire control computer and on expiry thereof to provide a control signal, and a laser radiation transmitter operable on receipt of a said control signal from said timer means to launch a laser radiation signal towards said target, said laser rangefinder and said laser radiation transmitter alternatively sharing a dual purpose laser and the radiation transmitter including a diverging: lens to provide a large laser beam spread whereby the laser radiation signal is detected in the vicinity of the target by the radiation detector in the base of the projectile to effect detonation thereof.