EP0411996B1 - Priming device for the pyrotechnic chain of subprojectiles - Google Patents

Description

The field of the present invention is that of priming devices for submunitions of cargo shells, in particular for anti-personnel and anti-vehicle grenades dropped in large numbers above a target, according to the so-called technique. of "saturation". A cargo shell is a shell whose usual explosive charge has been replaced by a large number of submunitions or sub-projectiles.

In most cases, the submunitions are grenades constituted by a cylindrical fragmentation body having an anti-personnel effect by projection of splinters, and closed at one end by a coating of hollow charge allowing aggression by the roof light or weakly armored vehicles. The other end of the body supports the initiating device responsible for initiating the explosive charge contained in the body.

Conventionally, these grenades are stacked on several columns inside the cargo shell, the priming device turned towards the base occupies the space left free by the coating of the hollow charge of the neighboring grenade, or is housed in a shape provided for this purpose in the base of the cargo shell.

The grenades are then ejected and dispersed on the trajectory of the shell during a phase known as stripping, with a speed of rotation around their axis which is close to the speed that the shell had at the time of stripping.

The main technical function of the initiating device is to ignite as safely as possible the initiation of the main charge of the submunition at the time of its impact, after a normal fire on the one hand, and prohibit this firing in the event of simple impact or manipulation on the other hand.

It can also include a device capable of neutralizing, that is to say preventing any ignition following a manipulation when after a normal launching the ignition has not occurred.

• Il y a une contrainte de forme et de dimensions. Cette contrainte provient de la nécessité de loger le dispositif d'amorçage dans le cône de charge creuse de la sous-munition suivante comme expliqué plus haut,
• Il y a ensuite une contrainte de masse, le dispositif d'amorçage situé à l'arrière de la sous-munition doit être aussi léger que possible de façon que le centre de gravité de la sous-munition soit situé aussi en avant que possible, ce qui favorise la stabilité sur trajectoire,
• Il y a enfin une contrainte liée aux conditions de tir de l'obus cargo, essentiellement par la nécessité de résister à la très forte accélération reçue par cet obus au cours de sa phase de balistique intérieure.

The constraints to be respected for the solution of the technical problem defined above are the following:

• There is a constraint of form and dimensions. This constraint comes from the need to house the priming device in the hollow charge cone of the next submunition as explained above,
• There is then a mass constraint, the priming device located at the rear of the submunition must be as light as possible so that the center of gravity of the submunition is located as forward as possible, which promotes stability on the trajectory,
• Finally, there is a constraint linked to the firing conditions of the cargo shell, essentially by the need to resist the very strong acceleration received by this shell during its interior ballistics phase.

The patents US4488488, WO8603828, EP0256320, US4612858 and FR2606136 describe different solutions for priming devices of this kind. Conventionally, the initiation systems described in these patents comprise ignitions constituted by a primer which a striker strikes at the moment of impact under the effect of its own inertia.

The firing safety can be supplemented by a self-destruction system ignited independently of the main firing and which causes the self-destruction of the submunition by firing the main charge after a certain delay .

The prohibition on firing in the event of impact or manipulation is ensured by latches which are only lifted following the rapid rotation of the submunition. The embodiment closest to the invention consists of the third version of the initiation device described in patent US4612858.

Conventionally, this priming device comprises a primer placed in a sliding drawer, which a striker strikes at the moment of impact, moved by its own inertia. The safety of firing is supplemented by self-destruction, the firing of which is caused by the rotation of the sub-projectile.

The prohibition of operation during simple manipulations or shocks stems from the fact that in the storage position the drawer is in a position such that the primer which it carries is not in alignment with the rest of the pyrotechnic chain and that the drawer is held in this position by the striker as long as the latter is not in the armed position.

This same spring neutralizes the priming system by bringing the drawer into a misaligned and locked position in the event of insufficient rotation speed or no impact after impact.

The self-destruction system comprises a primer secured to the drawer and coming under the effect of centrifugal force to strike a striker secured to the body of the primer device. This primer in turn initiates a retarding composition placed in a groove formed on a face of a disc interposed between the initiation system and the main charge, and having in the axis of the striker a priming relay that can be initiated, either by the main primer or by the retarding composition.

A vent, practiced laterally in the housing of the concurrent primer and coming in relation to the retarding composition, allows its initiation.

This device has many drawbacks. We can first note that all the operational safety features are lifted under the action of centrifugal force alone, which is penalizing from the safety point of view.

Concerning the self-destruction device, it can be noted that the method of loading the retarding composition is difficult to implement. It will be difficult to obtain a homogeneous composition, ensuring good regularity of combustion, and thereafter delays which are reproducible from one priming device to another.

It will also be difficult to vary these times, the combustion time being directly dependent on the length of the load, except to modify this length and therefore the disc, or to change composition.

Nor is there found in this device an interruption of the pyrotechnic chain between the priming relay and the retarding composition which is a sensitive element, which is a serious drawback from the security point of view.

In the case of jamming of the primer holder drawer in an intermediate position, without the primer of the self-destruction device being initiated, the drawer will not be in the neutralization position; an unexpected initiation is then possible following a manual manipulation of the grenade after falling on the ground.

Finally, this priming device is composed of a large number of parts, which makes it an expensive assembly. In particular, the body is a complex foundry part generally made from a zinc alloy and it ensures both the housing of the different parts as well as the fixing and the maintenance of the priming device on the body of the sub- ammunition.

Patent DE3144996 describes a security and arming device which is intended to equip a projectile. This device comprises a latch disposed in a longitudinal direction of the device and which disappears under the action of the projectile starting acceleration.

The amplitude of the erasure of this lock as well as the period during which it remains erased depends on the conditions of firing of the projectile. Thus, to be operational, the lock must be able to move away from the rotor only for significant accelerations. When the firing conditions are not correct, the lock returns to immobilize the rotor and prevents its passage into the armed position.

When the ammunition is dispersed over the ground, it is no longer subjected only to the acceleration of gravity which is insufficient to ensure the spacing of such a lock which is dimensioned to detect a shot made under conditions correct (accelerations of the order of 16,000 g).

The invention therefore relates to a device of the type described in US Pat. No. 4,612,858, but by design and construction having increased safety, this with a reduced number of mechanical parts, while respecting the constraints associated with this. kind of devices, which were explained above. Finally, it aims to produce a priming device comprising more reliable and possibly removable self-destruction means, and reliable neutralization means. Said document US 4,612,858 describes the characteristics of the preamble of claim 1.

• un tiroir porteur d'une amorce, mobile dans une rainure transversale d'un corps d'une position de sécurité dans laquelle l'amorce n'est pas alignée avec la suite de la chaîne pyrotechnique à une position armée dans laquelle l'alignement est réalisé,
• un premier percuteur mobile dans un alésage longitudinal et venant frapper l'amorce lors de l'impact de la sous-munition,
• au moins un moyen de blocage du tiroir dans sa position de sécurité,
• des moyens de neutralisation comprenant un obstacle qui, actionné par un ressort vient s'interposer sur le trajet du tiroir, caractérisé en ce qu'un deuxième percuteur est monté sur ledit tiroir,
• les moyens de neutralisation comprennent une gachette montée pivotante relativement au corps et maintenue par ledit ressort dans une position telle qu'une de ses extrémités constituant l'obstacle vient empêcher tout passage du tiroir à sa position armée dans le cas où ce dernier n'est pas venu prendre sa position armée après la chute de la sous-munition sur le sol de façon à empêcher tout passage ultérieur de ce dernier dans sa position armée, la gachette étant fixée apte à basculer contre l'action du ressort sous l'effet d'un mouvement de rotation axial de la sous-munition, ladite extrémité n'interdisant alors plus les mouvements du tiroir,
• ladite extrémité de ladite gachette constituant l'obstacle comporte en regard dudit deuxième percuteur un logement, dans lequel le deuxième percuteur pénètre en position de neutralisation.

The subject of the invention is therefore a device for initiating a pyrotechnic chain for submunition of cargo shells comprising an explosive charge contained in an envelope, of the type comprising:

• a drawer carrying a primer, movable in a transverse groove of a body from a safety position in which the primer is not aligned with the rest of the pyrotechnic chain to an armed position in which the alignment is realized,
• a first movable striker in a longitudinal bore and striking the primer upon impact of the submunition,
• at least one means for locking the drawer in its safety position,
• neutralization means comprising an obstacle which, actuated by a spring interposes on the path of the drawer, characterized in that a second striker is mounted on said drawer,
• the neutralization means comprise a trigger pivotally mounted relative to the body and held by said spring in a position such that one of its ends constituting the obstacle prevents any passage of the drawer to its armed position in the case where the latter is not not come to take its armed position after the fall of the submunition on the ground so as to prevent any later passage of the latter in its armed position, the trigger being fixed capable of rocking against the action of the spring under the effect of 'an axial rotational movement of the submunition, said end then no longer prohibiting the movements of the drawer,
• said end of said trigger constituting the obstacle comprises, opposite said second striker, a housing in which the second striker enters the neutralization position.

This construction has the advantage of locking the drawer in a known position and preventing the priming of the main chain on the one hand and of a possible delay chain on the other hand.

In fact, in the system proposed by the closest prior art, the neutralization device requires a movement of the drawer bringing the latter into a neutralization position, movement which cannot take place if the drawer is blocked.

The device proposed by the invention by interposing a mechanical obstacle on the path of the drawer ensures such neutralization whatever the state of the springs actuating the drawer.

Such an arrangement also makes it possible to avoid the storage of energy inside the device. Indeed, the spring is not held in the banded position inside the device; it is only tensioned during the rotation of the submunition, which reduces the risk of degradation of the spring during the storage phases.

In a variant, the device according to the invention comprises a delay self-destruction means constituted by a primer, a delay cord, a priming relay and a striker mounted on the drawer.

Such a variant makes it possible to obtain an easy design delay since the cord is produced independently of the initiating device.

• l'amorce est un inflammateur sensible à la percussion et le cordeau retard est relié à cet inflammateur par une cheminée ;
• le moyen d'autodestruction comporte deux pièces supports permettant son encliquetage sur le corps. Ce mode de réalisation permet de faciliter le montage du moyen d'autodestruction à retard sur le corps du dispositif d'amorçage. Il permet également d'utiliser des cordeaux de longueur différente avec le même montage du dispositif d'amorçage ;
• le logement présente une forme complémentaire de celle du deuxième percuteur de façon à réaliser un coincement de ce dernier s'il vient à pénétrer dans le logement.
• le premier moyen de blocage du tiroir comprend trois éléments alignés selon un axe fictif YY' parallèle à l'axe longitudinal XX' de la sous-munition, ces éléments étant une masselotte prenant appui dans un logement du corps pour bloquer le tiroir, un ressort guidé d'un côté sur une faible distance par un pion fixé au corps et ajusté de l'autre côté dans un alésage de la masselotte, et un évidement aménagé dans le corps tout autour de l'axe YY′.
• il comporte un deuxième moyen de blocage du tiroir qui est constitué par une collerette solidaire du percuteur et sur laquelle vient en appui un logement aménagé sur le tiroir, et en ce que les efforts aérodynamiques s'exerçant sur un ruban solidaire du percuteur provoquent la translation de ce dernier et la libération du tiroir, et en ce que lorsque le tiroir est immobilisé dans sa position de sécurité par le premier moyen de blocage, la collerette vient se loger dans une rainure portée par le tiroir, rainure empêchant toute translation du percuteur dans son alésage longitudinal.
• le percuteur comporte un alésage axial fermé par une rondelle, dans lequel coulisse une tige, comportant à une de ses extrémités un épaulement coopérant avec la rondelle pour extraire le percuteur, le mouvement de traction étant produit par le ruban fixé à l'extrémité libre de la tige.
• un masque métallique extérieur dont la forme intérieure épouse la forme extérieure du corps, le masque métallique étant fixé par un sertissage sur une gorge portée par l'enveloppe de la charge, et le corps étant maintenu en contact avec le masque par un disque de fermeture venant lui même en appui sur la charge.

According to other characteristics:

• the primer is an igniter sensitive to percussion and the delay cord is connected to this igniter by a chimney;
• the self-destruction means comprises two support parts allowing it to snap onto the body. This embodiment makes it easier to mount the delay self-destruction means on the body of the initiating device. It also makes it possible to use cords of different length with the same mounting of the priming device;
• the housing has a shape complementary to that of the second striker so as to wedge the latter if it comes to enter the housing.
• the first locking means of the drawer comprises three elements aligned along a fictitious axis YY 'parallel to the longitudinal axis XX' of the submunition, these elements being a counterweight bearing in a housing of the body to block the drawer, a spring guided on one side on a low distance by a pin fixed to the body and adjusted on the other side in a bore of the counterweight, and a recess arranged in the body all around the axis YY ′.
• it comprises a second means for blocking the drawer which is constituted by a collar secured to the striker and on which bears a housing arranged on the drawer, and in that the aerodynamic forces exerted on a ribbon secured to the striker cause the translation of the latter and the release of the drawer, and in that when the drawer is immobilized in its safety position by the first locking means, the collar comes to be housed in a groove carried by the drawer, groove preventing any translation of the striker in its longitudinal bore.
• the striker has an axial bore closed by a washer, in which a rod slides, comprising at one of its ends a shoulder cooperating with the washer to extract the striker, the tensile movement being produced by the ribbon fixed to the free end of the stem.
• an external metal mask whose internal shape matches the external shape of the body, the metal mask being fixed by crimping on a groove carried by the envelope of the load, and the body being kept in contact with the mask by a closing disc itself coming to bear on the load.

• La Figure 1 est une vue en coupe d'un obus cargo.
• La Figure 2 représente une coupe longitudinale partielle de deux sous-munitions empilées montrant le système d'amorçage selon l'invention.
• La Figure 3 représente une coupe transversale d'un premier mode de réalisation du dispositif, coupe réalisée selon le plan AA de la figure 2.
• La Figure 4 représente une coupe de la sécurité d'accélération réalisée selon le plan EE de la figure 3.
• La Figure 5 représente une coupe du système d'allumage selon le plan BB de la figure 2.
• La Figure 6 est une coupe de la figure 3 suivant le plan CC.
• La Figure 7 représente la même coupe que la figure 6, le percuteur étant en position armée.
• La Figure 8 représente en coupe axiale un deuxième mode de réalisation du dispositif, coupe réalisée selon le plan DD de la figure 10.
• La Figure 9 est une demi coupe du dispositif selon le plan FF de la figure 10 montrant la sécurité d'accélération.
• La Figure 10 est une coupe transversale suivant le plan GG de la figure 12.
• La Figure 11 est une coupe suivant les plans brisés HH de la figure 12.
• La Figure 12 est une coupe axiale suivant le plan II de la figure 11.

Other characteristics and advantages will appear on reading the following description of embodiments given without limitation with reference to the drawings in which:

• Figure 1 is a sectional view of a cargo shell.
• Figure 2 shows a partial longitudinal section of two stacked submunitions showing the priming system according to the invention.
• FIG. 3 represents a cross section of a first embodiment of the device, section made along the plane AA of FIG. 2.
• FIG. 4 represents a section of the acceleration safety produced according to the plane EE of FIG. 3.
• FIG. 5 represents a section of the ignition system according to the plane BB of FIG. 2.
• Figure 6 is a section of Figure 3 along the plane CC.
• Figure 7 shows the same section as Figure 6, the striker being in the armed position.
• FIG. 8 shows in axial section a second embodiment of the device, section made along the plane DD of FIG. 10.
• Figure 9 is a half section of the device along the plane FF of Figure 10 showing the acceleration safety.
• Figure 10 is a cross section along the plane GG of Figure 12.
• Figure 11 is a section along the broken planes HH of Figure 12.
• Figure 12 is an axial section along plane II of Figure 11.

The priming system for submunitions of cargo shells 1 according to the invention is intended as explained above to be mounted on submunitions 2, housed in large numbers in this shell. Each submunition is designed so that the priming device for one is housed in the space left free inside the coating of the hollow charge of the next submunition. The detail of this housing is shown in Figure 1 in which we see the coating 3 of hollow charge of a submunition comprising an explosive charge 4, coating inside which is housed the initiating device 5 of the neighboring submunition. This figure is intended to illustrate the conventional arrangement of submunitions 2 in the shell, the priming system being oriented towards the base 6 of the shell.

As shown in Figure 2, the initiating device according to the invention, shown in the safety position, consists of a body 7, disposed inside a metal mask 44 made of stamped sheet metal and the internal profile follows the external profile of the body 7.

The mask 44 thus covers the body 7 which supports all of the priming means, the body being kept in contact with the mask by a closing disc 13 itself bearing on the explosive charge 4.

The mask carrying the initiating device is joined to the explosive charge by means of an annular crimping 45 on the metal casing 47 of the charge (see FIG. 7), but any other mode of connection would be possible. The mask constitutes a reinforcement of the body and allows it to be dimensioned allowing the use of plastics. In fact, the forces transmitted during movements of the submunitions by the parts constituting the initiating device according to the invention will be absorbed by the mask, the rigidity of which is sufficient. This avoids having to use a complex profile foundry to produce the initiation device.

Inside the body 7 is arranged a transverse groove 48 inside which is slidably mounted a drawer 8, carrying a primer 9. The drawer is pushed into its groove by a compression spring 10 bearing on one side on one end 11 of a recess arranged in the drawer and on the other on a lug 12 of the closing disc 13 of the body 7.

The body also has a longitudinal bore 49 inside which a striker 16 is slidably mounted.

The latter comprises an axial bore 50 inside which is disposed a sliding rod 32, the latter carries a shoulder 35 intended to abut on a washer 36 made integral with the striker 16 by crimping.

A textile tape 31 is linked to the telescopic rod 32 by means of a washer 33 held by a crimping 34.

The striker also carries a flange 15 which is received when the device is in the safety position in a groove 14 of the drawer 8, which thus immobilizes the striker in translation.

Figures 3 and 4 show a first blocking means constituted by a counterweight 18, bearing in a housing 29 of the body 7 and on an imprint 46 made on the drawer so as to block the latter (fig 3). The counterweight is held in position by a compression spring 19, adjusted on one side in a blind bore of the counterweight 18 and guided on the other side over a short length by a pin 20 secured to the body 7.

Conventionally, this lock is designed so as to function only during sufficient accelerations and strokes of the counterweight (acceleration of the order of 900 g), this in order to protect against accidental unlocking consecutive to rough handling or falls during storage or handling periods.

It will be noted that the counterweight 18, the spring 19 and the pin 20 are aligned along an axis YY ′ parallel to the longitudinal axis XX ′ of the submunition and to the acceleration vector of the projectile at the start of the shot. A recess 30 is arranged in the body 7 all around the axis YY '(see Figure 5), the function of this recess will be explained below.

Thus before firing the cargo shell, any translation of the drawer is prohibited by the locking means.

When the latter is erased and the sub-projectiles are no longer in the cargo shell (in fact in the latter case the drawer cannot pass into the armed position due to its pressing on the coating of the hollow charge of the sub- neighboring ammunition), a limited translation of the drawer is possible until the housing 17 arranged in the drawer is pressed on the flange 15 which thus constitutes a second means of blocking the drawer.

The drawer is then still immobilized in a safety position but the flange 15 is released from the groove 14, allowing translation of the striker.

The drawer 8 carries a pin 38 (Figure 3) pushed by a spring 39, intended to engage in a hole 40 of the body 7 so as to lock the drawer in the armed position.

In FIGS. 3, 5 and 6 there is a representation of a self-destruction device comprising a striker 24 integral with the drawer 8, and a retarder assembly consisting of a primer 21 and a priming relay 22 , set on a flexible delay cord 23.

The priming device according to the invention also comprises a neutralization means comprising a centrifugal trigger 25 held in the safety position shown in FIG. 3 by a torsion spring 26 and accommodating its free end 51 between the striker 24 and the primer 21 of the delay system, thus creating an obstacle preventing any passage of the drawer into its armed position. The trigger carries at its free end 51 opposite the striker 24 a housing 43 whose function will be explained below.

The retarder assembly is fixed to the outside of the body 7 by support pieces 27 and 28 made integral with the body 8 by means of a snap not shown (see Figures 3, 5 and 6).

The operation of the device is as follows:
At the start of the blow, the shell undergoes an acceleration and a rotation. By inertia, the counterweight 18 then compresses the spring 19 along the axis YY ′ and is found in the recess 30. The rotation of the projectile generating a centrifugal force, the counterweight 18 is offset and wedged across the recess 30.

This offset is favored by the small diameter of the spring 19 and by the fact that the very short pin 20 offers practically no guidance. The drawer 8 is no longer linked to the body by the counterweight 18 and can then slide slightly, within the limit permitted by the housing 17 of the striker 16 and by the support of the drawer on the coating of the neighboring sub-projectile.

The counterweight 18 cannot, as a result of its offset, return to its place even after the acceleration phase has ended.

Note that the recess 30 being free over 360 ° relative to the axis YY ′ (see Figure 5), the counterweight 18 will be trapped regardless of the orientation of the submunition in the shell, no indexing submunition / shell is therefore no longer necessary during assembly, which simplifies the integration of submunitions into the cargo shell.

During the unloading, the submunitions are ejected out of the shell with a speed of rotation around their axis substantially equal to that of the shell at the time of the unloading.

The centrifugal force causes the separation of the trigger 25, as well as the translation of the drawer 8 pushed by the spring 10, the flange 15 is then released from the groove 14, and the striker free to translate.

It should be noted that the extraction of the striker 16 is not instantaneous, but only takes place once the strip 31 has been deployed and the rod 32 has come out of its housing (FIG. 7). This arming delay makes it possible to avoid during unloading that two submunitions by colliding do not work unexpectedly.

The ribbon 31 (fig 7) is deployed and pulls the telescopic rod 32 which abuts on the washer 36, then extracts the striker 16 from its housing 17.

The drawer then passes into the armed position and at the same time, the striker 24 initiates the self-destruction device, the drawer is locked by the pin 38 engaged in the hole 40.

The positioning of the primer 9 is ensured by the lug 12 on which the end 37 of the spring housing 10 comes into abutment.

• l'attitude de la sous-munition est contrôlée par le ruban 31 dont l'efficacité est renforcée par la tige télescopique 32 qui permet de reculer le point d'application de la force de freinage engendrée par le ruban 31 et d'augmenter le couple anti-basculement.
• la rotation de la sous-munition est freinée par un dispositif aérodynamique du type connu, non représenté (par exemple des ailettes solidaires du corps de la sous-munition). La vitesse de rotation décroît et avec elle la force centrifuge maintenant la gâchette.

During the descent:

• the attitude of the submunition is controlled by the tape 31, the effectiveness of which is reinforced by the telescopic rod 32 which makes it possible to move back the point of application of the braking force generated by the tape 31 and to increase the torque anti-tip.
• the rotation of the submunition is braked by an aerodynamic device of the known type, not shown (for example fins attached to the body of the submunition). The speed of rotation decreases and with it the centrifugal force holding the trigger.

On impact, the submunition hits the target on the side of the hollow charge and at the same time undergoes a very strong deceleration. By inertia the striker 16 strikes and initiates the primer 9 and consequently the hollow charge 4.

If, however, the submunition sees its fall braked gradually, for example by branches holding the ribbon 31, the initiation of the charge is nevertheless ensured by the self-destruction device.

The primer 21 has ignited the delay cord 23 which will initiate the primer 9 by means of the priming relay 22 and through two recesses 41 and 42 made respectively in the drawer 8 and the body 7 (FIG 7).

It will be noted that the self-destruction sequence begins when the ignition device passes into the armed position and continues thereafter, whatever the environmental conditions encountered by the submunition during its fall, which constitutes a guarantee of reliability.

It will also be noted that this self-destruction can only initiate the main charge if the drawer 8 is in the armed position, the recess 41 then being opposite the recess 42.

Otherwise, the primer 9 being misaligned, the operation of the relay 22 will have no consequences on the main load, which is advantageous from the safety point of view.

In addition, if for any reason the drawer 8 could not slide and therefore the arming to be carried out, the submunition would be on the ground, all means of blockage out of service and anyone handling it could then loosen the drawer 8 and cause the percussion of the delay.

Such a drawback is avoided thanks to the neutralization means proposed by the invention. In fact when the rotation of the sub-projectile is finished, the trigger 25 pushed by its spring 26 returns to the safety position shown in Figure 3. In this case it limits the movements of the drawer 8 by preventing it from coming into the armed position and initiating the delay.

It is possible to give the housing 43 and the trigger 25 a shape such that the return of the latter to the safety position is possible whatever the intermediate position between the storage position and the armed position adopted by the primer holder drawer.

The shape of the housing 43 is complementary to that of the striker 24 so as to produce, in the event of displacement of the drawer bringing this striker inside the housing 43, an irreversible jamming of these elements, which increases the safety of the device during subsequent manipulations.

Figures 8 to 12 show a second embodiment of the initiating device according to the invention, in which elements similar to those described above have the same reference numerals.

In this particular embodiment, the body 7 is a foundry of a zinc alloy (Zamac) produced for example by the lost wax process.

As before, it comprises a drawer 8 disposed in a transverse groove 48 of the body 7, and held by a closing disc 13 made integral with the body 7 by a not shown fixing means (screws or rivets).

The drawer is pushed by the spring 10 which bears on one side on a lug 12 of the disc 13.

In this particular case and for mounting convenience, the spring 10 is disposed on a rod 52 which allows it to be compressed in order to place it in its housing, a split washer 53 is introduced between the spring 10 and the head of the rod 52 by an opening 54 of the disc 13. This washer thus secures the rod 52 and the drawer 8.

The striker 16 is slidably mounted in the longitudinal bore 49, in this variant it does not have a telescopic rod, but carries the textile tape 31 fixed by means of a washer 33 held by a crimping 34.

The flange 15 of the striker 16 is housed in the groove 14 of the drawer 8 which thus immobilizes the striker in translation.

A steel strapping 55 receives the priming system and is made integral with it by transverse connecting means not shown (screws or rivets), it makes it possible to make the priming system integral with the body of the load (not shown here) at by means of an annular crimp similar to the crimp 45 shown in FIGS. 6 and 7.

The rotating brake fins 56 are folded over the hoop 55 and welded to it by one of their ends.

In this particular embodiment, the locking of the drawer in the armed position is ensured by a plunger 57 slidably mounted in a housing 58 of the body 7 and pushed by a spring.

When the drawer is in the armed position, the lug 12 abuts on the end 37 of the spring housing 10, the plunger coming into the housing 17.

This plunger is held by a cover 59 made of plastic material which is supported on a flat face of the body 7 and made integral with the latter by rivets (not shown).

The cover 59 also carries the pin 20 which guides the spring 19 of the counterweight 18 (see FIG. 9), this counterweight constitutes the first means of blocking the drawer 8 as has already been described for the first embodiment.

Figures 10, 11 and 12 show the self-destruction device which comprises as before a striker 24 secured to the drawer 8, and a retarder assembly consisting of a primer 21, a priming relay 22 and a flexible delay cord 23 (see Figures 11 and 12).

In this particular embodiment, the primer is an percussion-sensitive igniter which is not attached to the delay cord but which is attached to the body 7 opposite the striker 24. A chimney 60, arranged in the body 7, connects the igniter to the delay cord 23.

Such an arrangement makes it possible to use a cord of reduced length and having only one curvature, which facilitates its positioning on the body 7 by simple adjustment inside the parallel transverse bores 61 and 62, and guarantees reliability. of transmission.

The flames produced by the initiation of the igniter will be guided by the chimney 60 and will initiate the delay cord 23 by means of an ignition composition 63 sensitive to heat or to the flame (for example a known mixture of Zirconium and Barium chromate).

The priming relay 22 will initiate the primer 9 through the recesses 41 (on the drawer 8) and 42 (on the body 7), and this only if the drawer 8 is in the armed position (FIG. 11).

The neutralization means (Figure 10) is as previously constituted by the centrifugal trigger 25 held in the safety position by the torsion spring 26, in this particular embodiment the trigger has at its end a housing, but it does not have a shape complementary to that of the striker 24 and does not make it possible to wedge the latter.

Claims (9)

1. Priming system (5) of a pyrotechnic chain for a submunition of a cargo shell comprising an explosive charge (4) contained in a casing (47), of the type comprising:

   - a slide mechanism (8) Carrying a primer (9), the slide moving in a transverse groove (48) of a body (7) between a safety position in which the primer (9) is not aligned with the Continuation of the pyrotechnic chain and an armed position in which alignment is achieved;

   - a first firing pin (16) that moves in a longitudinal bore (49) and strikes the primer (9) at the time of impact of the submunition;

   - at least one device for immobilising the slide in its safety position;

   - a disarming system comprising an obstacle which, under the action of a spring (26), moves into the path of the slide (8), characterised in that a second striking pin (24) is mounted on the said slide (8);

   - a disarming system Comprising a trigger (25) pivotally mounted relative to the body (7) and held by the said spring (26) in a position such that one of its ends (51) Constituting the obstacle prevents any movement of the slide to its armed position if the said slide has not moved to its armed position after the submunition has struck the ground so as to prevent any subsequent movement of the said slide into its armed position, the trigger (25) being attached so as to swing against the action of the spring (26) under the effect of a movement of axial rotation of the submunition, the said end (51) then no longer preventing the movements of the slide;

   - the said end (51) of the said trigger (25) constituting the obstacle comprises opposite the said second striking pin (24) a housing (43), into which the second striking pin (24) penetrates in the disarming position.
2. Device according to claim 1, characterised in that it comprises a delayed self-destruct mechanism consisting of a primer (21), a delay cord (23), a secondary priming system (22) and the second striking pin (24) mounted on the slide (8).
3. Device according to claim 2, characterised in that the primer (21) is a percussion-sensitive inflammatory device and in that the delay cord is connected to this inflammatory device through a passage (60).
4. Device according to claim 2, characterised in that the self-destruct mechanism comprises two support brackets (27, 28) whereby it snaps on the body (7).
5. Device according to one of the claims 1-4, characterised in that the housing (43) has a shape matching that of the second striking pin (24) such that the said striking pin will be trapped if it penetrates into the housing (43).
6. Device according to one of the claims 1-5, characterised in that the first means of blocking the slide comprises three parts aligned along a notional axis YY' parallel to the longitudinal axis XX' of the submunition, these parts being a weight (18) bearing in a recess (29) of the body (7) to block the slide (8), a spring (19) guided on one side over a short distance by a pin (20) attached to the body and fitting at the other side into a bore in the weight (18) and an opening (30) made in the body (7) around the axis YY'.
7. Device according to one of the claims 1-6, characterised in that it comprises a second means of blocking the slide, this second means consisting of a collar (15) attached to the striking pin (16) and upon which bears a recess (17) made in the slide (8), and in that the aerodynamic forces exerted on a tape (31) attached to the striking pin (16) causes the said pin to move in translation and release the slide (8), and in that when the slide is immobilised in its safety position by the first means of blocking, the collar (15) enters a groove (14) made in the slide, preventing any translation movement of the striking pin in its longitudinal bore (49).
8. Device according to one of the claims 1-7, characterised in that the striking pin (16) comprises an axial bore (50) closed off by a washer (36), in which slider a rod (32) which together with the washer (36) can extract the striking pin (16), the traction movement being produced by the tape (31) attached to the free end of the rod (32).
9. Priming device according to one of the claims 1-8, characterised in that it comprises an external metal mask (44) the internal shape of which matches the external shape of the body (7), the metal mask being attached by crimping (45) on a groove in the casing (47) of the shell (4), and the body being maintained in contact with the mask by a closure disc (13) which itself bears on the shell (4).

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