GB2181523A

GB2181523A - Missile decoy systems

Info

Publication number: GB2181523A
Application number: GB08525121A
Authority: GB
Inventors: Stanley Beddoe
Original assignee: Plessey Co Ltd
Current assignee: Plessey Co Ltd
Priority date: 1985-10-11
Filing date: 1985-10-11
Publication date: 1987-04-23
Also published as: WO1987002445A1; DK298587D0; EP0241505A1; DK298587A

Abstract

An inductive coupling arrangement for use in missile decoy systems employing mortars or rockets, in which the inductive coupling arrangement comprises a primary part (2) including electric coil means and associated magnetic core structure which forms part of the launcher barrel structure for the mortar or rocket and a secondary part (4) which forms part of a rocket or mortar or multiple mortar pack and includes electric coil means (7) and associated magnetic core structure (8), the primary and secondary parts being mechanically separate parts but magnetically coupled with one another and the secondary part embodying an electro-magnetically operated device (13) operable by the magnetic flux produced in response to the electric pulse energy transmitted through the coupling arrangement for the operation of the rocket or mortar firing fuse means in response to an electrical output produced by the secondary coil means.

Description

SPECIFICATION Improvements relating to missile decoy systems This invention relates to missile decoy systems in which infra-red mortars for generating infra-red decoy radiation or chaff-dispensing rockets for providing radar decoy chaff clouds are arranged to be fired from suitable launching means usually carried bythepotential missiletarget (e.g. ship) sothaton- coming heat-seeking or radar controlied missiles are diverted away from the real target.

For the purpose offiring the mortar or rocket, as the case maybe, launching means may include the primary part of an induction coupling arrangement which facilitates the transmission of electrical energy to the mortar or rocket within the usual barrel ofthe launching means for firing ofthe rocket or mortar, as the case may be.The secondary part of this induction coupling arrangement may be embodied in the mortarorrocketor, in the case where a multiple mortar pack is provided including plurality of mortars (e.g. seven) to be fired sequentially to provide an infra-red display moving progressively away from the missile target as the mortars generate their respective displays at increasing distances from the ship or other target, the secondary part of the inductive coupling arrangement may be embodied in the lower end of a multiple mortar pack which will be inserted into the launcher barrel. As regards the latter mortarfiring arrangement attention is hereby directed to ourco-pending Patent Application No.

8411977 (F.13162).

The electrical energy transmitted through the inductive coupling arrangementforfiring the mortar or rocket, as the case may be, may comprise electrical pulses derived from charged capacitor means connected in the inputcircuittothe inductive coupling arrangement. Due to relatively high eddy current losses in the inductive coupling arrangement the electrical power available in the secondary part ofthe arrangementwill besufficienttooperatefusemeans forfiring the rocket or mortar but it may not be sufficientto provide electrical powerforthe operation of electro-magnetic stepping means for the sequential firing ofthemortarina multi-mortarpackforex- ample of the form disclosed in the above referred to patent application.

According to the present invention therefore there is provided an inductive coupling arrangement for use in missile decoy systems generally of the kind described, in which the inductive coupling arrange ment comprises a primary part including electric coil means and associated magneticcorestructurewhich forms part of the launcher barrel structure for the mortaror rocket and a secondary part which forms part of a rocket or mortar or multiple mortar packand includes electric coil means and associated magnetic core structure, the primary and secondary parts being mechanically separate parts but magnetically coupled with one another and the secondary part embodying an electro-magnetically operated stepping device operable by the magnetic flux produced in response to the electric pulse energy transmitted through the coupling arrangement for the operation ofthe rocket or mortar firing fuse means in response to an electrical output produced by the secondary coil means.

By the direct operation of the electro-magnetic stepping device formed integrally with the sec ondarypartofthecoupling arrangement losses are avoided that would otherwise be suffered if the electrical output from the secondary coil of the arrangement were converted back into electro-magnetic en ergyfor subsequent operation of an electromagnetic stepping device completely separate from the inductive coupling arrrangement.

Byway of example the present invention will now be described with reference to the accompanying drawing in which: Figures 7 and 2 show cross-sectional and end views of an inductive coupling arrangementaccording to the present invention.

Referring to the drawing the inductive coupling arrangement comprises a primary part for attach mentto the base of a rocket or mortar launcher barrel. This primary part includes a hollow cylindrical magnetic structure 1 which hasa shallow channel- shaped cross section and which accommodates a primarywinding ortransmitcoil 2. The cylindrical magnetic structure 1 may be enclosed within a not magnetic protective envelope 3. In operation ofthe arrangement the coil 2 will be electrically connected to pulse generating means (not shown) which may be operated to apply to the primary coil an electrical pulse of low frequency as by switching a charged capacitor into the primary coil circuit.The axis ofthe primary partwill be co-axial with or paraliel to the axis of the launcher barrel.

The secondary part of the inductive coupling arrangementwhich is adapted to be attached to the rocket, mortaror multiple mortar pack is indicated at4and includes a generally cylindrical non-magnetic housing 5 which fits freely into the central aperture 6 of the primary part of the coupling arrangement. The housing 5 encloses a secondary winding 7 which embraces a tubular magnetic core structure 8 having an enlarged flange at one end thereof defining one pole piece 9. Another pole piece loins secured to the other end ofthe housing 5 and is provided with pole extensions 11 and 12 which are positioned for cooperation with an armature 13 rotatably mounted, as by bearings, in the pole piece 9.

When the primary winding 2 is energised by a low frequency current pulse derived from the aforesaid pulse generating means the magneticflux produced in the magnetic structure 8 and the associated pole pieces 9 and 10 of the secondary part of the coupling arrangement will pass through the air gaps between the fixed pole piece extensions 11 and 12 to the rotatably mounted armature 13. By magnetic attraction the armature will accordingly be rotated through a relatively small angle so that the air gaps between the pole piece extensions 11 and 12 and the armature 13 will be reduced. As the armature is rotated switching means (not shown) mechanically coupled thereto will be indexed in orderto direct a firing pulse produced by the coupling arrangement to a rocket or motor, as the case may be, located within the launcher barrel.This firing pulse is derived from the MMF induced in the secondary winding 7 as a result of the change of magnetic flux in the magnetic core structure and armature circuit as the armature is rotated.

As will be appreciated from the foregoing description of one embodiment of the invention, the electromagnetic stepping device is operated directly in response to the magnetic coupling between the primary and secondary parts whilstthe pulse forfiring the mortar or rocket, as the case may be, is derived from the secondary winding in response to the change in magneticflux dueto rotation of the armature of the stepping device. Contacts ofthe stepping device directthefiring pulse so produced to the rocket or motor fuse, as appropriate. By arranging thatthe stepping device is operated directly by the induction coupling device arrangement the need to convert an electrical outputfromthe induction coupling arrangement back into electro-mechanical en ergyfortheoperation of a stepping device is avoided thereby achieving a significant saving in electrical power.

Claims

1. An inductive coupling arrangement for use in missile decoy systems employing mortars or rockets, in which the inductive coupling arrangement comprises a primary part including electric coil means and associated magnetic core structure which forms part of the launcher barrel structure for the mortar or rocket and a secondary part which forms parts a rocketormortarormultiplemortarpackand includes electric coil means and associated magnetic core structure, the primary and secondary parts being mechanically separate parts but magnetically coupled with one another and the secondary part embodying an electro-magnetically operated device operable by the magnetic flux produced in response to the electric pulse energy transmitted through the coupling arrangementforthe operation ofthe rocket or mortarfiring fuse means in response to an electrical output produced by the secondary coil means.

2. An inductive coupling arrangement as claimed in claim 1, in which the primary part comprises a hollow cylindrical magnetic structure which has a shallow channel-shaped cross-section in radial directions and which accommodates a primary coil and in which the secondary part comprises a tubular magnetic structure which carries a secondary winding and which has extending therethrough the shaft ofthe armature of an electro-magneticstepping devicewhich rotates between magnetic pole pieces in response to the pulse operation of the device.

3. An inductive coupling arrangementsubstanti- ally as hereinbefore described with reference to the accompanying drawing.