WO2015075411A1

WO2015075411A1 - A countermeasure payload container

Info

Publication number: WO2015075411A1
Application number: PCT/GB2013/053090
Authority: WO
Inventors: Gordon William FLAWS
Original assignee: Wallop Defence Systems Ltd
Current assignee: EST Defence Company UK Ltd
Priority date: 2013-11-22
Filing date: 2013-11-22
Publication date: 2015-05-28
Anticipated expiration: 2016-05-22
Also published as: GB2520810A; EP3071926A1; GB201417087D0; GB2520810B

Abstract

A countermeasure payfoad container comprises a metallic body, which in use, is insertable into a countermeasure cartridge; wherein said body is of a tubular shape which is closed at a first end and open at second end.

Description

The invention relates to air countermeasure cartridges and in particular to an intertable countermeasure payload container.

A known countermeasure cartridge comprises a countermeasure payload material, which Is pressed into a pellet prior to being located within an aluminium payload container. Or alternatively the pressed countermeasure payload material is wrapped in a protective aluminium foil

The common disadvantage of these known countermeasure cartridge configurations is that the forming of the countermeasure payload pellets requires additional handling and tooling stages before the pellet is loaded in to the container, or wrapped in an aluminium foil; which makes the manufacturing of the counter payloads both complicated and expensive,

Another known countermeasure cartridge comprises a countermeasure payload material which is subsequently compressed into a plastic container.

The disadvantage of the known countermeasure cartridge is that the inner surface of the plastic container is smooth, which is required for its subsequent release in the moulding process and therefore does not provide an adequate surface for the compressed payload pellet to attach itself to the container. This problem is known to occur when the payload container comprising the compressed countermeasure pellet is exposed to an increased thermal environment, which causes the payload container to expand and the retained compressed countermeasure pellet to detach itself from the payload container.

It is an objective of the invention to solve at least some of these disadvantages.

Summary of the Invention in a first broad independent aspect, the invention provides a countermeasure payload container comprising a metallic body, which in use, is insertable into a countermeasure cartridge,- wherein said body is of a tubular shape which is dosed at a first end and opens at second end.

This configuration provides an improved payload container, which allows a compressive ram device (also known as a drift) to be inserted into the open end of the tubular container, to facilitate in the simple and efficient compression of a countermeasure material against the closed end of the payload container. The metallic body augments the payload container body so that it can also function as a mould tool for supporting the contained countermeasure material, and therefore able to withstand the large compressive forces applied to a contained countermeasure payload material during the compression cycle, without deforming the configuration of the payload container itself. Therefore, preventing the deformation of the payload container is critical, because the loaded payload container will be assembled into a void within countermeasure cartridge case, which conforms to high tolerances and precise dimensions.

A further advantage of this configuration is that the support provided to the powdered countermeasure material, from the metallic body enables the manufacturing of longer countermeasure payioads pellet Therefore, the whole countermeasure payload within the payload container is formed from one increment (e.g. one compression cycle), without comprising the configuration of the payload container, or providing loose payload pellets which result from an inadequate compression of the powdered payload material.

Preferably, said body is of a circular tubular shape. The advantage of this configuration is that it enables the countermeasure container to be inserted within a circular counter measure cartridge. Preferably, said body is formed from aluminium based material The advantage of this configuration is that it provides a container that is both durable, light weight and therefore does not compromise the deployment and flight characteristics of the countermeasure payload. Furthermore, the countermeasure payload consumes the aluminium payload during its burn cycle, whereby the burning aluminium contributes to the infra-red output of the activated countermeasure payload.

Preferably, a countermeasure payload container further comprises a counter measure payload. This configuration provides a countermeasure payload, which can be easily and quickly inserted In to a countermeasure cartridge.

Preferably, said countermeasure payload is formed from a compressible material, This configuration provides a countermeasu e payload which can be easily and efficiently formed within a countermeasure payload container.

Preferably, said compressible material is a powder. This configuration enables a compressible countermeasure payload material to be poured into the payioad container, which is then subsequently compressed to form a solid payload.

Preferably, said compressible material further comprising a magnesium material, teflon material and viton materials. This configuration provides a countermeasure payload that burns in excess of 1000 degrees Celsius, and therefore provides the heat source for the counter measure payioad

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Figure 1 shows a cross-sectional view of a loaded countermeasure payload container,

Figure 2 shows a cross-sectional view of an assembled countermeasure cartridge, which comprises a loaded countermeasure payload container.

Figure 1 shows a cross-sectional view of a loaded countermeasure payload container generally indicated by 1, which incorporates a countermeasure payload material 2. The payload container 1 further Incorporates a closed end 3 and an open end 4, which incorporates a void 5 between the open end 4 of the container 1 and the countermeasure payload material 2.

The countermeasure payload material 2 is initially in a powder form, prior to being poured into the container 1. The payload material 2 is then subsequently compressed by a compression ram means or drift (not shown) which is inserted into the open end 4 of the payload container 1 and compresses the countermeasure material to form a

countermeasure pay ad pellet The void S is formed by the compression of the countermeasure payload material, which is caused by the subsequent reduction of the volume of the payload material powder when compressed in to a solid pellet form.

The payload container is configured into a cylindrical can type configuration, which is formed from an aluminium alloy. The container comprises a 24millime†re (mm) outside diameter, a wall comprising a 0.6mm and the length of the container is 70mm, These dimensions are nominal dimensions and it is intended that the invention Is not limited to these dimensions only.

The countermeasure payload container is initially filled with the powder countermeasure material until the powder is either flush or sub flush with the open end of the

countermeasure container.

Figure 2 shows a cross-sectional view of an assembled countermeasure cartridge generally indicated by 10. The cartridge 10 has an aluminium outer case 1 and an aluminium countermeasure payload container 1, also known as a pellet tube.

The outer case 11 is of a substantially circular configuration which is closed at one end 12,

An end cap element 13 is located within the open end 14 of the outer case 11 and is typically retained by the means of a friction fit The outer elongated side surface of the payioad container 1 abuts the inner elongated side surface of the outer case 1 1, thereby preventing any axial movement of the counter measure payioad container 1 relative to the outer case 11 of the cartridge 10,

The dosed end 12 of the outer case 1 1 comprises a centrally located squib activation device 15 which extends from the outer surface of the bottom portion 12, to an inner payioad chamber of the outer case 11. A bottom Ό¹ ring sealing element 6 is located between the open end of the payioad container 1 and the closed end 12 of the outer case 1 1. The bottom Ό'-ring sealing element 16 is located about the squib activation device 15. A second top 'G'-ring sealing element 17 is located between the closed end 3 of the payioad container 1 and the end cap 13 of the cartridge 10, Both top and bottom 'O'-ring sealing elements 16 and 17 are formed from a deformable material, which is compressible to enable each of them to provide a good seal.

The open end 4 of the payioad container 1 incorporates a void 18 which is located between the activation squib device 15 and the countermeasure payioad material 2 contained within the payioad container 1. This void comprises a ragged surface, which provides an increased surface area for catching the initiating flame from the activated squib device 15.

In use, the aluminium payioad container is filled with a powdered countermeasure material, which is then subsequently compressed by a single compression ram (or drift member) that is subsequently inserted into the open end of the payioad container and compresses the powdered payioad material into a solid pellet However, prior to the compression, a burnable material, i.e. a pyrotechnic composition (or the like), is poured onto the composition of countermeasure powder material This has the effect of providing a quicker manufacturing process for forming the countermeasure pellet, which does not. require any manual priming subsequently to the pellet being pressed. The payioad material is typically a powdered compound that comprises Magnesium, Teflon and Vilon (MTV) materials.

The metallic payioad container provides a robust construction, which comprises an outer wall and/or outer diameter that does not deform due to the compressive forces being exerted on to the closed end of the payioad container. This is Important due to the required tolerances within the dimensions of the paybad container and the outer case of the cartridge, which enables the payioad container to be inserted into the cartridge, whereby no voids exists between the payioad container and outer case of the cartridge. This prevents any axial movement of the payioad container, relative to the outer case of the cartridge. The support provided to the countermeasure payioad material, by the metallic payioad container, enables lighter compression bads to be applied for forming an adequate countermeasure pellet if an inadequate compression force Is applied to the countermeasure material it would result in a loose pellet being formed and may break up upon the initial ejection from the cartridge case.

The metallic payioad container is typically formed from a lightweight aluminium material.

The adequate compression of the countermeasure payioad enables the countermeasure pay ad pellet to be formed from increment (e.g. one compression operation operation), this may result in the countermeasure payioad material being poorly consolidated at the bottom of the case; however this does not cause a problem with regards to the claimed invention.

Furthermore, the support provided by the metal payioad container facilitates the manufacture of long countermeasure paybads, whereby each payioad comprise a length that is greater than the diameter of the payioad, without compromising the configuration of the paybad container along its length.

The metallic payioad container provides an inner surface that is suitable for the powdered countermeasure material to key too during the compression cycle. When the compressed payioad pellet and incorporated the payioad container are exposed to an increased thermal environment, the keyed surface of the paybad container prevents the compressed paybad pellet from becoming detached from the payioad container due to any subsequent expansion of the payioad container relative to the compressed payioad pellet

Initially a bottom portion of the outer case of the cartridge will incorporate the squib activation device, whereby the squib forms a seal when it is pressed into the bottom portion of the outer case. A bottom O-ring sealing element is then inserted into the bottom of the outer case of the cartridge which surrounds the squib activation device. The bottom 'Ο'- ring sealing element functions as a deformable supporting element, which fills the void between the open end of the payload container and the closed end of the outer case of the cartridge. Both top and bottom Ό^'-rings thereby support the countermeasure payload container when incorporated within the cartridge.

When the end cap is located into the opened end of outer case, it seals and compresses the top 'O'-ring sealing element against the dosed end of the payload container and prevents the ingress of moisture at the end cap. Typically, both top and bottom Ό' rings are of an identical large section configuration, which can cater for a large tolerance on the length of the pressed countermeasure pellet. The typical working tolerances are in the range of 2.5 to 3 millimetres on the length of the pressed countermeasure pellet. It is essential that the countermeasure payload container is adequately supported by top and bottom Ό' -rings, which revents any movement of the countermeasure payload container relative to the outer case of the cartridge. Such movement may cause friction, which could generate heat and could subsequently initiate the countermeasure cartridge unintentionally.

When activated, the compressed payload material, which has been compressed into a payload countermeasure pellet will burn in a "cigarette - like" fashion, once it has been ignited by the squib activation device. The burning of the countermeasure payload pellet will begin with the ragged end faced that faces the squib activation device and will hum along the entire length of the squib pellet until ail the countermeasure material has been consumed and is extinguished by the closed end face of the payload container. The constant length and diameter of the pressed countermeasure pellet provides a

predetermined burn rate for countermeasure pellet, so the time duration of the active burn cycle of a countermeasure payload can be accurately determined.

When activated, the burning payload pellet will also consume the countermeasure payload container (starting at the burning face which is the face that faces the squib activation device), whereby the consuming of the aluminium container contributes to the infra-red output of the countermeasure payload pellet This provides the Increased advantage of being seen by a missile threat within the infra-red band of the heat seeker spectrum. The pressing directly into the aluminium pay oacf container substantially reduces the time required to manufacture the loaded payload containers when compared to more conventional construction methods. The use of only one compressive ram or drift provides a simple solution to this manufacturing method.

In an alternative embodiment of the invention a groove configuration may be Incorporated into the ragged exposed end face of the countermeasure payload pellet in another alternative embodiment, imc stearate material may be used to lubricate the pressing operation of the countermeasure payload material within the payload container.

The assembly of the countermeasure cartridge will comprise of the following process steps:

« Loading an activation squib within the bottom portion of the outer case of the cartridge;

® Inserting a first 'Ο' ring sealing element into the bottom of the outer case of the cartridge.

® inserting a countermeasure payload container on top of the first V ring sealing element;

» Inserting a second Ό' ring sealing element on top of the countermeasure container located within the cartridge; and

* Inserting an end cap into the open end of the cartridge's outer case, whereby the closure of the cartridge compresses the first and second Ό' rings elements installed within the cartridge.

The assembly of the countermeasure payload comprises the following process steps:

» Pouring a powdered countermeasure material into a payload container;

® inserting a compression ram (or drift) into the open end of the payload container;

* Compressing the powder countermeasu e material within the payload container until the powder countermeasure material forms a pellet; and

* Removing the compression ram (or drift) from the payload container after

compression.

Claims

1. A countermeasure payioad container comprising a metallic body, which in use, is insertable into a countermeasure cartridge; wherein said body is of a tubular shape which is closed at a first, end and open at second end.

2. A container according to claim 1 , wherein said body is of a circular tubular shape.

3. A container according to either of the preceding claims, wherein said body is

formed from aluminium based material,

4. A container according to any of the preceding claims, further comprising a counter measure pay bad,

5. A container according to claim 4, wherein said countermeasure payioad is formed from a compressible material

6. A container according claim 5, wherein said compressible material is a powder.

7. A container according to either of claims 5 and 6, wherein said compressible

material further comprising a magnesium material, teflon material and viton materials,

8. A container according to claims 4 to 7, wherein said countermeasure payioad

further comprises a continuous end face, which is opposite a second end face arid abuts said closed end of said container.

9. A countermeasure cartridge comprising a countermeasure payioad container m accordance with any of the above claims,

10. A cartridge according to claim 9, further comprising a case body incorporating an aperture, wherein said container is insertable into said case body via said aperture and comprises an outer surface that abuts an inner surface of said case body. i

11. A cartridge according io claim 10, further comprising an end cap element for closing said aperture

12. A cartridge according to claim 11, further comprising a first 'O' ring sealing

element located between said dosed first end of said container and said end cap element.

13. A cartridge according to claim 12, further comprising a second Ό^' ring sealing element located between a dosed base portion of said case body and said open second end of said container. 4. A cartridge according to any of the preceding claims 9 to 13, further comprising a squib activation device arranged in said base, portion of said case body,

15. A countermeasure cartridge comprising a case body and a countermeasure payload located within said body, wherein a countermeasure payload material is compressed within a metallic tubular container which is closed at a first end and open at a second end. 6. A method of forming a countermeasure payload comprising the steps of:

® locating a ram device into an open first end of a metallic tubular container of a countermeasure payload, whereby said container is closed at a second end;

* moving said ram towards said closed second end of said container;

» compressing said countermeasure material within said container; and

» removing said ram from said open first end of said metallic tubular container.

17. A method of assembling a countermeasure cartridge comprising the steps of:

* Insert a first Ό' ring sealing element into a countermeasure cartridge case;

® inserting a loaded countermeasure paytoad container onto said first Ό' ring sealing member within said cartridge case;

® Inserting a second Ό' ring sealing element on top of said payload container within said cartridge case; and ® Inserting an end cap element into said cartridge case to cover said second '0' ring sealing member.

18. A countermeasure payload container as substantially where with described the in accordance with the text and Figure 1.

19. A countermeasure cartridge as substantially hereinbefore described and/or illustrated in the accompanying text and/or Figure 1.

20. A method of form ng a countermeasure payload as substantially hereinbefore described and/or illustrated in the accompanying text and/or Figure 1..

21. A method of assembling a countermeasure cartridge as substantially hereinbefore described and/or illustrated in the accompanying text and/or Figure 1.