EP3114424B1 - Decoy cartridge for aircraft - Google Patents

Description

The present invention relates to the field of lures, in particular for the protection of aircraft, such as aircraft and / or helicopters.

Various devices for forming lures, especially in the infrared range have already been proposed. Examples of known devices can be found in the documents GB 2,300,035 , DE 100 65 816 , DE 34 43 778 and US 2,868,129 . The document GB 2300035 forms a starting point for the preamble of independent claim 1.

The aforementioned documents describe systems comprising a plastic sheath which houses a charge intended to form a lure. The means described in the aforementioned documents based on a plastic sheath for containing the load, however, have generally been abandoned in recent times in favor of a very different solution for confining the film-based filler, the more often aluminum, wound on the load. As will be seen later the use of an aluminum film wound on the load has indeed been considered to offer advantages.

In all architectures of air decoy cartridges of different calibers and shapes (round, square, rectangular), designed to equip and protect planes and helicopters against missiles with infrared homing, we find today an adhesive paper envelope wafer or aluminum, folded and surrounding a body of radiation (compressed infrared pyrotechnic composition also called "infrared block") contributing to the ignition and the setting regime thereof.

The present invention aims to improve the known devices of the type illustrated on the figure 1 attached.

For many years, lure-emitting devices have been proposed and used for emitting infrared radiation in accordance with the figure 1 attached.

We can see on the figure 1 a cartridge comprising two main parts: an assembly 10 comprising a sleeve 11 and a impeller 12, on the one hand, and an assembly 20 intended to be ejected, on the other hand.

The assembly formed of the sleeve 11 and the impeller 12 is designed to be secured to a loader itself integrated with a launcher.

Set 10 remains in the magazine after firing.

• un ensemble 21 formant corps de radiation (bloc infrarouge),
• un ensemble 22 formant partie pyrotechnique équipé d'une charge d'allumage 23 et d'un tiroir de sécurité 24 intégrant un doigt d'armement assurant une rupture de chaîne pyrotechnique tant que l'ensemble éjecté 20 n'est pas sortie de la douille 11.
• un couvercle de fermeture 25 placé à l'avant du bloc infrarouge 21, et

• une enveloppe 26 adhésive en papier tramé ou aluminium pliée pour entourer le bloc infrarouge 21 et assurer également une liaison mécanique et étanche avec l'ensemble partie pyrotechnique 22 et le couvercle de fermeture 25.

The ejected assembly 20 comprises:

• a set 21 forming a body of radiation (infrared block),
• an assembly 22 forming a pyrotechnic part equipped with an ignition charge 23 and a safety slide 24 integrating an arming finger ensuring a pyrotechnic chain break until the ejected assembly 20 is out of the socket 11.
• a closure cover 25 placed at the front of the infrared block 21, and

• an envelope 26 of folded aluminum paper or folded to surround the infrared block 21 and also provide a mechanical and sealed connection with the pyrotechnic assembly 22 and the closure cover 25.

The device illustrated on the figure 1 works as follows:

The ignition of the impeller 12 causes the ejection 20 to be ejected from the socket 11 and the initiation of the ignition charge 23 of the pyrotechnic unit 22.

Once the ejected assembly 20 is completely out of the socket 11, the safety slide 24 is released (there is no longer a pyrotechnic chain break) and thus the ignition charge 23 can initiate the infrared block 21.

The adhesive envelope 26 made of ruled paper or aluminum confines the block 21 to ensure that the infrared block 21 is put into operation and put under pressure.

The adhesive envelope 26 of screen paper or aluminum tears or dislocates at the end of the startup.

The radiation body 21 can thus radiate and emit an infrared signature simulating that of airplanes or helicopters.

The use of an envelope 26 formed of an aluminum paper makes it possible to adapt the distribution of the envelope on the body of radiation, for example by locally combining, if desired, several layers of paper, to modulate the confinement of the radiation body and thus allows good reproducibility of the desired radiation curves

It has also been found that the realization of the envelope 26 of aluminum foil allows easy tearing during the implementation, to leave the radiation body visible.

However, until today, it has been necessary to manually wind the aluminum foil forming the envelope on the radiation body, partly because of the nature of the radiation body in question. avoid any risk of inadvertent initiation to manufacture, and secondly to ensure a perfect application of the envelope on the entire surface of the body of radiation to prevent initiation from outside the body of radiation although drawer 24 is always in the safety position.

In fact, the slightest tear in the manufacturing process, in the envelope 26, is likely to lead to an ignition of the radiation body, from the outside, through such a tear, even if the assembly 20 to be ejected is still in the bushing 11, in the safety position of the drawer 24.

The manual winding of the aluminum foil allows a visual check of the quality of the winding.

However, the risk of tearing of the envelope when the assembly 20 is engaged in the sleeve 11 can not be totally excluded.

• d'améliorer la maîtrise de la reproductibilité de la mise en régime du pain,
• d'améliorer la robustesse de la conception en terme sécuritaire, et
• de réduire significativement les coûts de production.

In this context, the present invention particularly aims at

• to improve the control of the reproducibility of the setting in regime of the bread,
• to improve the robustness of the design in terms of security, and
• significantly reduce production costs.

• une partie pyrotechnique d'amorçage,
• une composition adaptée pour émettre un rayonnement dans le domaine infrarouge, et
• une enveloppe de protection de la composition, formée d'une gaine en matière plastique,

l'un au moins d'un corps de partie pyrotechnique d'initiation et/ou d'un bouchon d'obturation de la gaine possédant une gorge annulaire qui débouche sur sa périphérie extérieure, caractérisé en ce que la gorge annulaire communique avec au moins un canal longitudinal lequel débouche sur une extrémité du corps ou du bouchon pour recevoir un ruban de colle polymérisable assurant le collage du corps et/ou du bouchon sur la gaine.These objects are achieved according to the invention by means of an infrared lure device according to independent claim 1, the device comprising:

• a pyrotechnic priming part,
• a composition adapted to emit radiation in the infrared range, and
• a protective cover of the composition, formed of a plastic sheath,

at least one of a pyrotechnic initiation body and / or a plug of the sheath having an annular groove which opens out at its outer periphery, characterized in that the annular groove communicates with at least one a longitudinal channel which opens on one end of the body or plug to receive a polymerizable adhesive tape ensuring the bonding of the body and / or plug on the sheath.

The casing is preferably a shaped rigid casing formed by extrusion.

• la figure 1 représente une vue en coupe éclatée d'un dispositif conforme à l'état de la technique,
• la figure 2 représente une vue générale en perspective avant l'assemblage d'un premier mode de réalisation conforme à la présente invention,
• la figure 3 représente une vue générale similaire en perspective avant l'assemblage d'un second mode de réalisation conforme à la présente invention,
• la figure 4 représente une vue générale similaire en perspective avant l'assemblage d'un troisième mode de réalisation conforme à la présente invention,
• la figure 5 représente une variante de réalisation conforme à la présente invention selon laquelle le bouchon de fermeture est intégré à l'enveloppe en matière plastique, et
• les figures 6, 7, 8 et 9 représentent respectivement une vue en perspective et une vue en coupe longitudinale d'un corps de partie pyrotechnique d'initiation et une vue en perspective et une vue en coupe longitudinale d'un bouchon conformes à l'invention, adaptés pour faciliter le collage desdits corps de partie pyrotechnique et bouchon sur une gaine.

Other characteristics, objects and advantages of the present invention will appear on reading the detailed description which follows and with reference to the appended drawings given by way of non-limiting example and in which:

• the figure 1 represents an exploded sectional view of a device according to the state of the art,
• the figure 2 represents a general perspective view before the assembly of a first embodiment according to the present invention,
• the figure 3 represents a similar general perspective view before assembling a second embodiment according to the present invention,
• the figure 4 represents a similar general perspective view before assembling a third embodiment according to the present invention,
• the figure 5 represents an alternative embodiment according to the present invention according to which the closure cap is integrated in the plastic envelope, and
• the Figures 6, 7, 8 and 9 represent respectively a perspective view and a longitudinal sectional view of a part body pyrotechnic initiation and a perspective view and a longitudinal sectional view of a plug according to the invention, adapted to facilitate the bonding of said pyrotechnic body and plug body on a sheath.

We find on the figure 2 , a lure device which comprises an assembly 110 comprising a bushing 111 associated with an impeller 112 and a portion 120 intended to be ejected.

The bushing 111 equipped with the impeller 112, preferably formed of an electric initiator, is adapted to be placed / co-operate with a launcher. Its structure is classic in itself and will not be described in more detail later.

The portion 120 intended to be ejected comprises a bread 121 of composition adapted to emit infrared radiation during its combustion.

The bread 121 is placed in a plastic sheath 130 according to the invention.

The sheath 130 is preferably formed of a tube of constant cross section whose side wall is continuous, solid, without opening out of its axial ends open.

This sheath 130 is closed at the front by a stopper 140 and at the rear by a pyrotechnic initiation portion 150. The latter preferably comprises a safety slide 160 capable of occupying two positions: on the one hand a safety position as the assembly 120 is housed in the sleeve 111 and secondly a release position when the assembly 120 is out of the sleeve 111.

In the safety position, the slide 160 is resiliently biased against the inner wall of the sleeve 111. It can not move transversely to the longitudinal axis of the assembly 120 because of its support on the inner surface of the sleeve 111, it ensures a break in the initiation transmission channel between the impeller 112 and the body or bread 121.

On the other hand, when the assembly 120 is ejected from the socket by propulsion gases produced by the impeller 112, the slide 160 having no support in view is moved (as schematized on the figure 2 ) and then authorizes an initiation transmission to the bread 121.

Once the bread 121 placed in the sheath 130, it is glued on the one hand on the pyrotechnic part 150 and on the other hand on the closure cap 140. The bread 121 is then perfectly confined and is avoided by safely any risk of inadvertent ignition from outside the bread 121.

It should be noted that the present invention makes it possible to dispense with the manual winding of the aluminum foil and therefore allows an automated and industrially usable assembly process, in particular for the insertion of the bread 121 into the bushing 111 and the gluing of the sheath 130 on the pyrotechnic part 150 and on the cap 140.

The operation of the device according to the invention remains globally identical to that of the prior device illustrated in FIG. figure 1 .

Upon the exit of the assembly 120 from the sleeve 111, following a bias of the impeller 112, the movement of the slide 160 allows the alignment of a fire transmission chip with the block 121 IR composition.

The Infrared 121 composition is then lit.

Depending on the nature and thickness of the sheath 130, it is either destroyed or moved relative to the bread 121 so that the desired infrared radiation is fully achieved.

It will be noted in the examination of figure 2 that the bread 121 is preferably longitudinally grooved to ensure a channeling of the initiation gases and ensure ignition of the bread 121 over its entire length.

More precisely according to the particular embodiment illustrated on the figure 2 , the bread 121 is provided with a series of grooves 122 on two opposite faces, for example 3 grooves 122 on respectively each of two opposite faces.

According to the variant illustrated on the figure 3 , the bread 121 is provided with one or more grooves 122 on each of its four faces.

The sheath 130 is preferably formed of polystyrene, ABS (acrylonitrile butadiene styrene), polypropylene, polyethylene or PA6.6 (polyamide 6.6).

More specifically according to the invention the material constituting the sheath 130 is advantageously transparent to ultraviolet (UV) to allow the application of ultraviolet radiation through the sheath to ensure the polymerization of an adhesive for fixing the sheath on the body 150 of the pyrotechnic initiation part and / or the stopper 140.

As indicated above according to the invention the sheath 130 is preferably formed of a tube of constant cross-section whose side wall is continuous, solid, without opening outside its axial ends open.

Appended figures are shown sheaths 130 formed of a rectilinear tube of constant square cross section. As a result, the bread 121 has an identical geometry, homothetic in dimensions to define a sufficient clearance to allow the engagement of the bread 121 in the sheath 130.

The use of a square section plastic sheath is more reliable than winding an aluminum film on a square section load. Indeed an aluminum film winding has weaknesses at its edges of the square section, that does not present a sheath formed for example by extrusion, molding or blowing.

Of course, the invention is not limited to this embodiment. It is conceivable to make sheaths 130 having any other section, for example a polygonal cross section that is different or circular.

Furthermore, sheaths 130 having a variable thickness along their length can be produced to control the rising edge of the radiation and its reproducibility.

Those skilled in the art will readily understand that the use of a sheath made of plastic, for example by molding or extrusion, avoids any risk of tearing and reduces production costs compared to the state of the art.

According to another advantageous characteristic of the present invention, the sheath 130 is made of an optically transparent material, at least in the infrared range and in the ultraviolet range. Thus the sheath does not disturb the diffusion of the infrared radiation emitted by the bread 121.

Tests carried out by the inventors have in fact demonstrated that the use of a sheath 130 of infrared-transparent material does not disturb the diffusion of the infrared radiation, whether in the power-up or maintenance phase. of the emission and whatever the behavior of the sheath 130, that is to say that the sheath 130 is ejected or destroyed by explosion.

The inventors have further determined that it is advantageous to provide a clearance, for example of 0.5 mm between the bread 121 and the sheath 130. Thus the device according to the invention safely allows a certain swelling of the bread 121, possible under the effect of aging or weather conditions. In this respect, the use of a sheath 130 of plastic material is an important advantage over the state of the art using an aluminum casing since such an aluminum casing practically does not tolerate swelling of the bread. , and tears during the first deformations of bread 121.

We have shown on the figure 5 an alternative embodiment according to which the closure cap 140 is integral with the sheath 130. Such a sheath 130 incorporating the cap 140 may for example be formed by blowing.

We have shown on the figure 4 an alternative embodiment of the sheath 130 having a series of grooves on its outer surface to facilitate the bursting of the sheath under the pressure of the gases generated by the bread 121.

Many grooving configurations can be provided for this purpose.

According to the particular embodiment illustrated on the figure 4 , not limiting, the sheath 130 comprises a longitudinal groove 132 on each of its faces, for example half width, and a series of transverse grooves 134. Those skilled in the art will understand that the presence of the grooves 132 and 134 forming breaking primers, facilitates the cutting of the sheath 130 into small segments and thus the bursting of the sheath 130.

We have shown on Figures 6, 7, 8 and 9 a particular embodiment of the body 150 of the pyrotechnic initiation portion and the cap 140, adapted to facilitate the bonding of said bodies 150 and cap 140 on the sheath 130.

More precisely according to the embodiment illustrated on the Figures 6 and 7 , the body 150 has an annular groove 152 which opens out over its entire outer periphery and which communicates with two longitudinal channels 154, 156 which open themselves on the end of the body 150 intended to be placed inside the sheath 130 .

Similarly according to the embodiment illustrated on the Figures 8 and 9 , the plug 140 has an annular groove 142 which opens out over its entire outer periphery and which communicates with two longitudinal channels 144, 146 which open themselves on the end of the plug 140 intended to be placed outside the sheath 130 .

During assembly, the body 150 is introduced into the sheath 130. A polymerizable adhesive is introduced into the channels 154 and 156 by means of a tool engaged in the sheath 130, to fill the groove 152. Thus, the adhesive tape contained in the The groove 152 comes into contact with the inner surface of the sheath 130. The glue can be polymerized at this stage of the assembly or subsequently, for example by UV irradiation through the sheath 130.

Once the assembly 120 comprising the bread 121 placed in the sheath 130, the stopper 140 can be put in place on the end of the Sheath 130. Similarly to the operation performed for the body 150, a polymerizable adhesive is introduced into the channels 144 and 146 accessible on the outside, by means of a suitable tool, to fill the groove 142. Thus the ribbon The adhesive contained in the groove 142 comes into contact with the inner surface of the sheath 130. The adhesive may be polymerized at this stage of the assembly or subsequently, for example by UV irradiation through the sheath 130.

Those skilled in the art will understand that the means for bonding the body 150 and the cap 140 described above with respect to the Figures 6 to 9 allow a simple, economical and reliable assembly.

These means are particularly suitable for a sheath 130 of ABS (acrylonitrile butadiene styrene), although the invention is not limited to the use of this particular material.

The polymerizable adhesive used in the context of the present invention may be subject to numerous variants.

By way of non-limiting example, it may be VITRALIT®, especially VITRALIT® UV 4050 which is an acrylate-based glue.

In a variant, the body 150 and / or the stopper 140 may comprise only one longitudinal channel 154 or 156, respectively 144, 146.

The tests carried out have shown that the aforementioned means allow a good mechanical strength of the assembly under the accelerations applied during the launch and in particular that the application of UV radiation to ensure the polymerization of the glue does not alter the mechanical properties and optical sheath 130. Thus the invention ensures a sealing bead and a mechanical strength ensuring safety and allowing the pressurizing of bread in operation.

By way of non-limiting example, the sheath 130 may have a thickness of the order of 0.5 to 0.9 mm.

A first technical effect obtained according to the invention is the improvement of safety compared to aluminum envelopes earlier because of the elimination of the risk of tearing before initiation.

A second technical effect obtained according to the invention results from the authorized clearance according to the invention, and prohibited by the prior winding technique, which allows a swelling in time of the IR composition.

A third technical effect obtained according to the invention results from the mechanical confinement of the bread 121 operated by the sheath 130 and impossible with an envelope of wrapped aluminum foil as soon as the stresses applied by the bread 121 exceed a certain threshold.

Tests carried out by the inventors have also demonstrated that the use of a plastic sheath 130 is fully compatible with the pyrotechnic environment involved and in particular that the use of such a sheath 130 of plastic material does not risk lead to an electrostatic charge level likely to induce inadvertent initiation of pyrotechnic elements or compositions involved in the device.

Moreover, the sheath 130 made of plastic mask less the flame of infrared bread 121 than a traditional aluminum paper. Indeed, because of its mechanical strength under pressure at more than one bar, the sheath 130 separates and bursts more easily than an aluminum spraying which is stuck on the bread 121 and which tends to stick on the bread 121 The positive consequence resulting from the invention is a better control of the ignition and a better reproducibility of the ignition.

Claims (12)

1. A device forming an infrared decoy comprising:

   - a triggering pyrotechnic portion (150), housed in a body of pyrotechnic initiation portion,

   - a composition (121) adapted to emit radiation in the infrared range,

   - an envelope (130) for protecting the composition (121), formed from a sheath made of plastic material, and

   - a closure plug (140) which blocks the sheath at the front,

   wherein one at least of the body (150) of the pyrotechnic initiation portion and/or of the plug (140) for blocking the sheath (130) has an annular recess (152, 142) which leads to its outer periphery, characterized in that the annular recess (152, 142) communicates with at least one longitudinal channel (154, 156; 144, 146) which leads to one end of the body (150) or of the plug (140) to receive a ribbon of polymerizable glue providing for gluing the body (150) and/or the plug (140) to the sheath (130).
2. The device according to claim 1, characterized in that the envelope (130) is a rigid profiled envelope formed by extrusion, molding or blowing.
3. The device according to one of claims 1 or 2, characterized in that the envelope (130) is made of a material chosen in the group comprising the following plastic materials: polystyrene, ABS (acrylonitrile butadiene styrene), polypropylene, polyethylene or PA6.6 (polyamide 6.6).
4. The device according to one of claims 1 to 3, characterized in that the envelope (130) is made of an optically transparent plastic material, at least in the infrared range.
5. The device according to one of claims 1 to 4, characterized in that the envelope (130) is made of an optically transparent plastic material, at least in the ultraviolet range.
6. The device according to one of claims 1 to 5, characterized in that the envelope (130) defines a clearance on the order of 0.5 mm around the composition (121) .
7. The device according to one of claims 1 to 6, characterized in that the envelope (130) is made in one piece with a closure plug (140).
8. The device according to one of claims 1 to 7, characterized in that the envelope (130) has a variable thickness.
9. The device according to one of claims 1 to 8, characterized in that the envelope (130) has a thickness on the order of 0.5 to 0.9 mm.
10. The device according to one of claims 1 to 9, characterized in that the sheath (130) comprises a series of grooves (132, 134) forming rupture initiators on its outer surface.
11. The device according to one of claims 1 to 10, characterized in that the composition (121) is longitudinally grooved to ensure channeling of the initiation gases.
12. The device according to one of claims 1 to 11, characterized in that the sheath (130) has a straight square section.

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