EP0538105B1 - Pyrotechnic cartridges with multiple compartments and corresponding ammunition - Google Patents

Description

The present invention is in the field of passive infrared (IR) or electromagnetic (EM) countermeasures to protect platforms such as light aircraft or helicopters when they are threatened by missiles equipped for example with seeker IR or EM, that is to say a guidance system operating in the infrared or electromagnetic field. This protection is done by attracting the missile away from the platform using infrared or electromagnetic decoys.

The present invention relates more particularly to pyrotechnic cartridges containing a plurality of payloads; after ejection, the combustion of these payloads creates infrared radiation comparable to the infrared signature of the platform to be protected, or after ejection, the dispersion of these payloads in the atmosphere creates a radar echo comparable to the equivalent radar surface (SER) of the platform to be protected. The missile guidance system is deceived by this device and the missile is moved away from the target platform.

The present invention also relates to the ammunition equipped with said cartridges. It is placed in a decoy launcher fixed on the platform to be protected, the decoy launcher is connected to the fire control unit. The ammunition comprises a rack receiving the said cartridges, a plate which ensures on the one hand the closing of the rack and on the other hand comprises the electrical connections with the decoy launcher and the electrical contacts with the cartridges.

The present invention also relates to an ammunition equipped with said cartridges and which acts as a decoy launcher: this ammunition is fixed directly on the platform and is connected to the fire control unit.

The cartridges known to date include a payload or several payloads arranged in series.

In particular, US Patents 4,063,485 (D1) on which the preambles of independent claims 1 and 6 are based, and US 3,808,940 (D2) describe decoy cartridges comprising separate and parallel tubes in which payloads are housed separate; these tubes are either welded to a support (D1) or held by a frame (D2). These payloads are ignited by wires passing through the open end of the tubes.

In the infrared field, the payloads are buns of pyrotechnic substance made from poorly performing compositions, these buns will therefore have a relatively large size to produce an infrared signature equivalent to that of the platform to be protected.

The resulting drawbacks are the large size of the cartridges, which limits their number for a given size of the ammunition. The ejection charges must be high, which implies a strong recoil at the start of the shot and requires reinforced parts (such as the locker or the plate) and therefore heavier.

In ammunition of the type described above and known to date the cartridges are fixed one by one in the rack by screws or elastic stop rings (circlips); likewise the plate closes the locker by screwing. The disadvantages of such devices are the difficulty of loading which requires more or less specific tools, and the duration of this loading due to numerous manipulations. Under these conditions, reloading the locker is not possible on the site of operations.

To overcome these drawbacks, an object of the invention is to reduce the size of the cartridges and optimize their storage to increase the number of shots available for the same size of the ammunition and for the same decoy effect (infrared signature and equivalent radar surface).

Another object of the invention is to simplify the loading or reloading operation so that it is done without the use of tools and in a limited number of manipulations to considerably reduce the duration of this operation: reloading on operational site , or in the immediate vicinity, is thus achievable.

The cartridge according to the invention contains a plurality of payloads which are ejected by pyrotechnic means. The cartridge consists of a sole integral with a case in which are housed a plurality of assemblies comprising pyrotechnic ejection charges, pyromechanical assemblies, ignition charges, payloads and lids. The cartridge is characterized in that the case is provided with several housings and comprises at its base a locking device in a locker, the above-mentioned assemblies are independent and are arranged in parallel in the various housings of the case, the sole is common to the different dwellings and includes electric primers. The pyromechanical device includes a pyrotechnic delay and operating safety devices to initiate the ignition charge which in turn will initiate the combustion of the payload, the safety devices interrupt this chain in the event of operating anomalies (assembly not ejected for example ).

Preferably, the device for blocking the cartridge in the locker consists of a bead located at the base of the case. By base of the case is meant the side of the case located near the sole. This bead also provides sealing between the rack and the cartridge.

Advantageously, the device for blocking the cartridge in the crate consists of a seal, housed in a groove located at the base of the case. This seal also provides sealing between the rack and the cartridge.

The cartridge case according to the invention has an odd number of housings. The positioning mode in the rack is indifferent. Preferably, the number of housings in the case is three.

According to a preferred embodiment, the cartridge according to the invention is such that the case consists of several housings produced by injection molding on the sole of a charged plastic material. Advantageously, this plastic material is electrically conductive.

For a particular embodiment of the invention, the payload of the above-mentioned assembly is constituted by a bread of pyrotechnic substance with strong radiation in the infrared during its combustion. By strong radiation is meant radiation equal to or greater than 60 J per gram of burnt substance, this energy being measured in band II from 3 to 5 µm.

For another embodiment of the invention, the payload of the above-mentioned assembly consists of products capable of creating a radar echo when they are dispersed in the atmosphere, after ejection. The products are flakes or metallic or metallized fibers, they are known in the state of the art.

The locker, loaded with its cartridges, is fixed on the plate. This plate closes the locker, it allows the identification of the nature of the payloads of the cartridges (payload producing infrared radiation or creating an echo-radar) by devices known in the state of the art. This plate also makes the electrical connection between the platform which receives the ammunition and the cartridges primers.

The ammunition comprising a plate as well as a monobloc rack, is such that this rack includes cells intended to receive and block the cartridges as previously described.

Advantageously, the munition according to the invention simultaneously contains cartridges of payloads radiating in the infrared and cartridges of payloads capable of producing a radar echo.

Advantageously also the ammunition receives cartridges whose length is greater than the depth of the cells of the rack. This arrangement allows rapid unloading of the locker.

According to a preferred embodiment of the ammunition, the monobloc rack loaded with its cartridges is fixed to the plate by means of a closing system comprising at least one quick hinge.

Advantageously, the closing of the plate on the rack is carried out by at least one quick hinge and a pawl.

Preferably, the locker comprises a retractable handle for handling the ammunition and for controlling the unlocking of the munition of the decoy launcher.

Advantageously, this ammunition comprises a first seal disposed at the rear of the rack, it provides sealing between the rack and the closing plate; and a second seal, placed around the crate, it seals between the crate and the decoy launcher.

In a particular embodiment of the munition, the rack loaded with its cartridges and fixed on its plate is mounted directly on the platform to protect: that is to say that the ammunition is not fixed in a decoy launcher, it constitutes itself the decoy launcher. It is fixed to the aircraft by pins, or stirrups, or any other device existing on the aircraft. It is connected to the shooting station by a cable and a connector which is connected to a connector arranged on the plate, for example at one of its ends.

Preferably, the rack is aerodynamically profiled, which reduces the drag due to the ammunition hung on the platform.

The aerodynamic profiling of the locker includes a rounded fairing for the leading edge and a dihedral-shaped fairing at the trailing edge. Preferably these leading edge and trailing edge fairings can extend over the entire height of the cartridges. Advantageously, the rack can constitute a side fairing with a height equal to that of the cartridges.

Advantageously, in a part of the trailing edge fairing, an oblong opening is created so as to produce a handling handle integrated into the rack. The different sharp edges are chamfered or rounded to make this handle convenient to use.

According to a preferred method of manufacture, the ammunition bin is produced by injection molding of a charged plastic material. Advantageously, this plastic material is electrically conductive.

In what follows the invention is explained in more detail with the help of figures representing a particular embodiment.

Figure 1 shows a partially exploded perspective view of a cartridge whose case consists of three lobes, forming three housings.

FIG. 2 represents an axonometric perspective of the ammunition, loaded with its cartridges with three lobes and closed by the plate, the ammunition is shown out of the decoy launcher, the latter not being shown.

Figure 3 shows, as before, the ammunition loaded with its cartridges, the last cartridge being partially engaged in its cell, the plate has been removed, it is not shown.

FIG. 4 is a detailed view of part A of FIG. 2.

Figure 5 shows a perspective view, partially exploded, of a munition, making decoy launchers.

FIG. 1 represents a cartridge 1 whose payload 9 is a loaf of pyrotechnic substance radiating in the infrared during its combustion. This cartridge comprises a sole 2 and a case 3. This case 3 has at its heel (end on the side of the sole) and over its entire outer periphery a bead 4. The sole 2 receives the electrical primers 5, one for each of the housings from the case. In each housing there is (following the electric primer 5) an ejection charge 6, a pyromechanical assembly 7 (pyrotechnic delay and operating safety), an ignition charge 8, the payload 9, finally the housing is tightly closed by a cover 10.

When the payload 9 is of the electromagnetic type, the assembly 11 is reduced to an ejection charge 6; the pyromechanical device is replaced by a simple piston ensuring the ejection of the payload 9. This payload consists of flakes or metallic or metallized fibers, the housing is closed in leaktight manner by a cover 10.

The case 3 and the bead 4 are in this example produced by injection molding around the sole 2 in of a polyether loaded with glass fibers and made conductive.

The bread of radiant pyrotechnic substance is made from a magnesium-polytetrafluoroethylene-epoxy composition implemented by compression or extrusion. This bread is for external combustion, or internal when it has a central channel.

The ignition charge 8 is a magnesium-polytetrafluoroethylene-fluorinated elastomer composition.

The electric pulse delivered by the decoy launcher initiates the electric primer 5; this primer is of the "1 ampere - 1 watt - 5 minutes fire-free" type existing in the catalog. The latter ignites the ejection charge 6 which on the one hand ejects, from a housing of the case 3, the stack 11: pyromechanical assembly 7, ignition charge 8, payload 9 and cover 10 and d on the other hand ensures the ignition of a pyrotechnic delay incorporated in the pyromechanical assembly 7.

At the outlet of the case 3, a mouth safety device, forming part of the pyromechanical assembly 7, realizes the alignment between the pyrotechnic delay and the ignition charge 8 and the latter then ensures the combustion of the loaf of pyrotechnic substances constituting the payload 9. The alignment between the pyrotechnic delay and the ignition charge 8 is interrupted by another safety device if the assembly "pyromechanical device-ignition charge and payload" meets an obstacle near the ejection point. The security devices mentioned above are of the type usually used in this field.

FIG. 2 represents the ammunition 20 constituted by a rack 21 which receives the cartridges 1, in this figure there are 24 cartridges each consisting of three lobes and comprising three housings which represent 72 strokes available. The locker 21 is closed by the plate 22. The retractable handle 23 (shown in the open position) is used for handling the ammunition, it also controls the device for unlocking the ammunition and the decoy launcher. The plate 22 is articulated and fixed to the rack by a quick hinge 25.

The enlargement shown in Figure 4 shows the detail of this part: the tab 26 secured to the plate has an oblong slot, emerging and inclined relative to the axis of the tab; this slot engages in a pin 27 integral with the rack 21, this pin constitutes the axis of rotation of the hinge. In the example presented, the plate has two identical hinges arranged at the ends of the same side of the plate. The plate is closed and locked on the locker by the elastic pawl 28 secured to the locker in this example. This simple and light manufacturing is achievable due to the low recoil force during the operation of the cartridges.

In Figure 3 we see the rack 21 (the plate 22 is removed) all the cartridges are in place except one which is shown partially engaged in the cell 29 which we see the shape suitable for housing the cartridges 1. The bead 4 of the cartridge 1 performs a sufficiently large forcing to prevent the cartridge from falling back in case the locker is overturned, but sufficiently weak for this forcing to be done manually. The cells 29 of the crate have, at their rear end, a shoulder which serves as a stop for the heel of the cartridge.

• la casier 31 équipé, dans cet exemple, de deux rangées de six cartouches tel les que précèdemment décrites ; seule une dernière cartouche 1 est représentée non engagée dans l'avéole 39 destinée à la recevoir,
• la platine 32 : réalise d'une part la fermeture du casier et d'autre part les contacts électriques avec les amorces des cartouches, l'une des extrémités de la platine comporte un connecteur 33 sur lequel se branche le cable assurant la liaison avec le poste de tir,
• les broches 34 fixent d'une part la platine sur le casier et d'autre part servent à fixer la munition sur la plate-forme à protéger.

On the other hand, the cartridges have a length greater than the depth of the rack and extend beyond the front face of the rack when they are in abutment on the shoulder. This arrangement makes it possible to extract them very quickly to remove them from the rack. When the plate is removed, it is enough to push on the outgoing part of the cartridge to make it slide out of the cell (we thus unlock the bead) we then withdraw the cartridge from the cell.
FIG. 5 represents an exemplary embodiment of the invention where the ammunition 30 also constitutes the decoy launcher: the ammunition is fixed directly on the platform to be protected and is connected by an electric cable to the fire control station.
The ammunition is shown partially disassembled, there are:

• the rack 31 equipped, in this example, with two rows of six cartridges such as those previously described; only a last cartridge 1 is shown not engaged in the aerosol 39 intended to receive it,
• the plate 32: on the one hand closes the locker and on the other hand the electrical contacts with the primers of the cartridges, one of the ends of the plate comprises a connector 33 on which the cable is connected ensuring the connection with the shooting post,
• the pins 34 fix on the one hand the plate on the rack and on the other hand serve to fix the ammunition on the platform to be protected.

The crate is identical to that of the example previously described in particular as regards the shape and dimensions of the cells 39 (depth of the cells 39 less than the length of the cartridges 1). As in the previous example, this rack is produced by injection molding.
However, the fixing of the plate 32 on the rack 31 is done here differently. Said plate 32 engages in a cell 38 at the base of the rack and the pins 34 come to fix it on the locker.

Finally the locker is profiled. This profiling is carried out very simply by a rounded shape 35 on the leading edge and by an acute dihedral shape 36 on the trailing edge. In addition, in the trailing edge there is an oblong opening 37: there is thus a handling handle incorporated in the rack; the different edges are chamfered or rounded to make it convenient to use this handle.

Claims (15)

1. Cartridge (1) consisting of a base plate (2) fixed to a case (3) in which there is housed a plurality of independent assemblies (11) disposed in parallel, comprising pyrotechnic ejection charges (6), pyromechanical assemblies (7), ignition charges (8), payloads (9) and caps (10), characterised in that:

   - the case (3) is provided with several housings and has at its base a device (4) for locking in a rack (21, 31),

   - the base plate (2) has, for each of the housings of the case (3), an electrical initiator (5).
2. Cartridge according to Claim 1, characterised in that the device (4) for locking in the rack (21, 31) consists of a strip situated at the base of the case (3).
3. Cartridge according to Claim 1, characterised in that the device (4) for locking in the rack (21, 31) consists of a joint housed in a groove situated at the base of the case (3).
4. Cartridge according to one of Claims 1 to 3, characterised in that the number of housings in the case (3) is equal to three.
5. Cartridge according to Claim 1, characterised in that the case (3) consists of several housings produced by injection moulding a plastic with a filler onto the base plate (2).
6. Munition (20, 30) comprising a plate (22, 32) and a monobloc rack (21, 31), characterised in that the rack has alveoli (29, 39) designed to receive and lock the cartridges according to any one of Claims 1 to 5.
7. Munition according to Claim 6, characterised in that it contains simultaneously:

   - payload cartridges (9) radiating in the infrared region, and

   - payload cartridges (9) suitable for producing a radar echo.
8. Munition according to one of Claims 6 to 7, characterised in that the length of the cartridges (1) is greater than the depth of the alveoli (29, 39) in the rack (21, 31).
9. Munition according to any one of Claims 6 to 8, characterised in that the rack (21), loaded with its cartridges (1), is fixed to the plate (22) by means of a closure system including at least one rapid-action hinge (25).
10. Munition according to Claim 9, characterised in that the closure system includes at least one rapid-action hinge (25) and a catch (28).
11. Munition (30) according to any one of Claims 6 to 10, characterised in that the rack (31) and its plate (32) constitute the decoy launcher.
12. Munition (30) according to Claim 11, characterised in that the rack (31) is aerodynamically profiled.
13. Munition according to Claim 12, characterised in that the profiling of the rack comprises a rounded fairing for the leading edge and a dihedron-shaped fairing towards the trailing edge.
14. Munition according to one of Claims 11 or 12, characterised in that the rear fairing has an oblong opening forming a handling grip.
15. Munition (20, 30) according to one of Claims 6 to 14, characterised in that the rack (21, 31) is produced by the injection moulding of a plastic with a filler.

Images