EP0756151B1 - Ignition system for a propulsive charge of a submunition ejected from a cargo munition - Google Patents

Description

The present invention relates to a system initiating the explosive charge of a submunition embedded in a carrier, this system comprising a main striker movable in translation, a primer holder mobile driven by a motor member of a safety position in which the primer is not aligned with the striker and the explosive charge, at a arming position in which this alignment is made, at least two means for locking the primer holder in a safe position before ejecting submunition, and a device for self-destruction of submunition after a predetermined delay.

A priming system of the aforementioned type is notably known from document FR-A-2 650 662.

At present, priming systems submunitions or bombs dispersed by a device wearer must meet security requirements at the locking means which retain the primer holder in its safety position to avoid accidental ignition of the explosive charge during the loading and handling phases of the carrier that precedes the shot, and be equipped a self-destruction device to avoid pollution of the land due to a malfunction in the priming system for submunitions.

The locking means which must be at less than two by NATO standards, are generally of the centrifugal type, i.e. the motor that frees the locks is constituted by the centrifugal forces which result from rotational movement imprinted on submunitions at moment of their dispersion, this rotational movement itself resulting from the rotational movement imparted to the carrier during firing.

• par une composition retard pyrotechnique logée dans le porte-amorce, mais une telle solution notamment décrite dans les documents EP-A-318 995 et 411 258 est coûteuse et ne permet pas de réaliser des retards d'une durée suffisante,
• par un retard électronique logé dans le porte-amorce, mais cette solution notamment décrite dans le document US-A-5,387,257 est complexe, coûteuse et oblige à prévoir une amorce électrique supplémentaire, une source d'énergie amorçable et des moyens de déverrouillage de l'auto destruction électronique,
• par un percuteur radial qui est libéré suite au fluage d'une goupille mise sous contrainte mais cette solution notamment décrite dans le documents EP-A-205 956 ne présente pas suffisamment de fiabilité, principalement dans la reproductibilité des temps d'auto-destruction et ne permet pas d'obtenir des durées de retard suffisantes, ou
• par un cordeau retard notamment décrit dans le documents FR-A-2 650 662.

A self-destruction device can be made up:

• by a pyrotechnic delay composition housed in the primer holder, but such a solution, in particular described in documents EP-A-318 995 and 411 258, is expensive and does not allow delays of sufficient duration,
• by an electronic delay housed in the primer holder, but this solution notably described in document US-A-5,387,257 is complex, costly and requires the provision of an additional electrical primer, a bootable energy source and means for unlocking the '' electronic self destruction,
• by a radial striker which is released following the creep of a pin under stress, but this solution notably described in documents EP-A-205 956 does not have sufficient reliability, mainly in the reproducibility of the self-destruction times and does not provide sufficient delay times, or
• by a delay cord notably described in documents FR-A-2 650 662.

Patent EP284923 describes a priming system for submunition which includes a primer holder drawer mobile under the effect of centrifugal force and which contains a pyrotechnic composition of self-destruction. The delay is initiated by a striker secured to a mounted lever swivel relative to the drawer. The lever switches by the effect of centrifugal force once the drawer is pulled out of the priming system body.

Generally speaking, submunitions are loaded into a carrier vehicle such as a cargo shell or an artillery rocket.

In the case of a cargo shell, the forces are generally sufficient to ensure in good conditions the release of the means of lock the primer holder and allow it to go into its arming position. In addition, submunitions scattered from a cargo shell have a time of flight in the range of 15s, so that all devices of self-destruction mentioned above can be used.

However, in the case of a rocket, the centrifugal forces are not always sufficient to secure the release of resources in good conditions locking the primer holder. In addition, submunitions scattered from a rocket have a time more than 30s, so that only delays from the electronic or cord type provide a delay corresponding to this flight time.

The object of the invention is to design a priming system for submunitions or bombs which is simple, easy to implement and able to present an excellent level of security and a good reliability of operation at the level of the locking the primer holder and the self-destruction device, a submunition equipped with such a system which can be fired by both a shell and a by an artillery rocket.

To this end, the invention proposes a system which is characterized in that one of the means of primer holder locking consists of a cam mobile driven by a drive member from a position of safety in which it forms a stop preventing the free passage of the primer holder to its cocking position, in a retracted position allowing free passage of the primer holder, in that it comprises two blocking means of the cam in a safety position which are released following the ejection of the submunition, and in that the cam carries an auxiliary striker to initiate a cord delay when the cam passes into its retracted position or of percussion after the ejection of the submunition.

According to another characteristic of the invention, the cam, in its safety position, includes a stop which is located on the path of movement of a finger secured to the primer holder to immobilize the latter in an intermediate safety position.

According to another characteristic of the invention, the means for locking the cam in its safety position include a finger secured to the primer holder and which rests on another stop of the cam when the primer holder is itself in its safety position, this finger retracting at the start of the movement of movement of the primer holder towards its position of weapons.

Advantageously, the means for blocking the cam in its safety position also include the body of a neighboring submunition embedded in the carrier.

In a manner known per se, the other means of locking the primer holder in its safety position consists of the main striker.

Generally speaking, the motor organs which allow the primer holder to pass into its position arming, and the cam to move into its position retracted or percussion are constituted by springs, these displacements can be completed by the action of the centrifugal forces to which they are subjected submunitions.

Generally speaking, submunition includes a body containing the explosive charge, body being surmounted by the priming device which includes a body in which are housed the striker, the primer holder and cam, and according to another characteristic of the invention, the delay line of the self-destruct device is wrapped around the body of the priming system.

A submunition, equipped with a system boot according to the invention, can be indifferently embarked on a cargo shell or rocket artillery, since the locking means of the primer holder and the cam are not released by centrifugal forces, and that the self-destruct device includes a cord whose length can be adapted during design to obtain delays compatible with the flight times of submunitions which are more important in the case of a dispersal from an artillery rocket.

In addition, the system's primer carrier priming can be constituted by a moving part in rotation or translation.

• la figure 1 est une vue en coupe longitudinale partielle de deux sous-munitions voisines embarquées dans un engin porteur,
• la figure 2 est une vue en coupe suivant la ligne II-II de la figure 1, le porte-amorce du système d'amorçage des sous-munitions étant dans sa position de sécurité,
• la figure 3 est une vue en coupe partielle suivant la ligne III-III de la figure 2,
• la figure 4 est une vue similaire à celle de la figure 1 lorsque le porte-amorce est dans sa position d'armement,
• la figure 5 est une vue en perspective de la came formant l'un des moyens de verrouillage du porte-amorce dans sa position d'armement,
• la figure 6 est une vue en coupe similaire à celle de la figure 2 mais le porte-amorce étant dans sa position d'armement,
• la figure 7 est une vue en coupe similaire à celle de la figure 2 lorsque la came est passée dans sa position de percussion du cordeau retard du dispositif d'auto-destruction,
• la figure 8 est une vue en coupe partielle selon la ligne VIII-VIII de la figure 7,
• la figure 9 est une vue en coupe partielle similaire à celle de la figure 2 pour illustrer l'un des moyens de blocage de la came dans sa position de sécurité, et
• la figure 10 est une vue en coupe partielle selon la ligne X-X de la figure 9.

Other advantages, characteristics and details of the invention will emerge from the explanatory description which follows, given with reference to the appended drawings, given solely by way of example, and in which:

• FIG. 1 is a partial longitudinal section view of two neighboring submunitions on board a carrier vehicle,
• FIG. 2 is a sectional view along line II-II of FIG. 1, the primer holder of the priming system for the submunitions being in its safety position,
• FIG. 3 is a partial sectional view along line III-III of FIG. 2,
• FIG. 4 is a view similar to that of FIG. 1 when the primer holder is in its cocking position,
• FIG. 5 is a perspective view of the cam forming one of the means for locking the primer holder in its cocking position,
• FIG. 6 is a sectional view similar to that of FIG. 2 but the primer holder being in its cocking position,
• FIG. 7 is a sectional view similar to that of FIG. 2 when the cam has passed into its position of percussion of the delay cord of the self-destruction device,
• FIG. 8 is a partial sectional view along the line VIII-VIII of FIG. 7,
• FIG. 9 is a partial sectional view similar to that of FIG. 2 to illustrate one of the means for locking the cam in its safety position, and
• FIG. 10 is a partial sectional view along line XX of FIG. 9.

Referring to Figure 1, a submunition 1 intended to be loaded into a vehicle carrier (not shown) contains an explosive charge 3 which, after ejection or dispersion of the submunition 1, is ignited by an ignition system 5 as a result of the impact of submunition 1 on the ground or on a target.

Cluster 1 includes a body metallic 7, hollow and tubular in shape. To one end, the body 7 is closed by a bottom wall 9, monobloc with body 7, and is surmounted by the system priming 5. Towards this end, the body 7 has a portion 11 of reduced outer diameter which delimits an annular shoulder 13 with the rest of the body 7.

Explosive charge 3 is hollow, i.e. which it defines towards the other open end of the body 7 of submunition 1, an internal space E of form frustoconical which is covered with a coating 15 of form complementary and finished with a circular skirt 15a made integral with the body 7.

In a manner known per se, several of these submunitions 1 are loaded into a carrier vehicle in being stacked on top of each other. This stacking is such that the priming system 5 and part 11 of reduced diameter of the body 7 of a submunition come be housed in the internal space E of the submunition previous, considering the loading direction of submunitions, shoulder 13 of the submunition coming to bear on the adjacent end surface of the body 7 of the previous ammunition, as is clearly visible in Figure 1.

The priming system 5 comprises a primer 18 carried by a piece or primer holder 20, and a striker main 22. The primer holder 20 is mounted movable in translation (drawer) or rotating (rotor or barrel) in the body 24 of the priming system 5, so that move from a safe position in which the primer 18 is not aligned with the striker main 22 and the explosive charge 3, at a position in which this alignment is carried out.

The body 24 of the priming system 5 is attached to the bottom wall 9 of the body 7 of the submunition 1 with interposition of a disc 26. The body 24 is capped by a metal mask 28 which extends by a circular skirt 30 by means of which it is fixed by crimping on the periphery of part 11 of reduced diameter of the body 7 of the submunition 1.

Referring to Figure 2, the body 24 of the priming system includes a first central part 24a which is partially surrounded by a second part peripheral 24b, substantially in contact with the mask 28, so as to delimit a free internal space E1 between the body 24 and the mask 28.

In the example illustrated on the different figures, the primer holder 20 is movable in rotation and will be referred to hereinafter as barrel 20.

The barrel 20 is mounted in a housing of the central part 24a of the body 24, so as to be free to rotate around an axis X-X perpendicular to the Y-Y axis of the submunition 1. The barrel 20 cooperates with an arming spring 33 which constitutes the member motor to move the barrel 20 into its position of weapons. Barrel 20 has a housing which contains the primer 18, this housing opening at the outside by two diametrically openings opposite 35.

The main striker 22 comprises a body cylindrical 40 terminated at one end by a point percussion 42. The body 40 is screwed into a nut 44 mounted in the peripheral part 24b of the body 24, so as to be aligned along the Y-Y axis of the submunition and next to barrel 20.

The barrel 20 armed with its spring 33 is maintained in its safety position by two means of locking.

Referring to Figure 1, a first locking means is constituted by the striker principal 22. More specifically, during the operations of mounting, the striker 22 is screwed into the nut 44 of way to engage with its percussion point 42 in a notch 46 provided on the periphery of the barrel 20 to immobilize the latter in its position of security.

The second barrel locking means 20 in its safety position is constituted by a cam 50. Referring in particular to FIG. 5, the cam 50 is generally circular in shape with a portion front 52 and rear part 54. The edge profile outside 55 of the front part 52 is circular with a radius of curvature substantially equal to that of the mask 28, while the profile of the outer edge 56 of the part rear is also circular, but with a slightly larger and noticeably radius of curvature equal to that of the skirt 15a of the load coating hollow 15. The profile of the inner edge 57 between the front 52 and rear 54 have two notches which delimit two stops 58 and 59 respectively. The face end of the front part 52 comprises a striker auxiliary 60 in the form of a tip.

Referring to Figure 2, the cam 50 is mounted inside the internal space E1 delimited between the body 24 of the priming system 5 and the mask 28. The cam 50 is rotatably mounted around an axis fixed 51 parallel to the Y-Y axis. Cam 50 is movable from a safety position to a retracted position under the action of a motor member constituted by a spring of weapons 62.

When the cam 50 is in its position safety, its stop 59 is in the trajectory of displacement of a finger 64 secured to the barrel 20. This stop 59 makes it possible to immobilize the barrel 20 in a intermediate safety position if the first means of lock constituted by the main striker 22 releases before dispersal of submunition 1.

The cam 50 is immobilized in its position of security by two locking means.

The first means of blocking the cam 50 is consisting of a finger 65 integral with the barrel 20. This finger 65 bears on the stop 58 of the cam 50 when the barrel 20 is in its safety position.

When the cam 50 is in its position safety, the outer edge 55 of its front part 52 is in contact with the internal wall of the mask 28, while the outer edge 56 of its rear part 54 is opposite an opening 28a of the mask 28.

The second means for blocking the cam 50 is constituted by a stop formed by the internal wall of the skirt 15a of the shell 15 of the submunition hollow charge neighbor against which the outer edge 56 of the rear part 54 of the cam 50 comes into contact with through the opening 28a of the mask 28, when the first cam blocking means 50 is released before the dispersion of the submunition (Figures 9 and 10).

The priming system 5 is completed by a self-destruct device 70 which is basically consisting of a delay cord 72 associated with the striker auxiliary 60.

The delay cord 72 is wound around the body 24 of the priming system 5, as is clearly visible in Figure 1, a spiral groove 74 being advantageously provided at the periphery of the body 24 to receive at least part of the delay cord 72. In referring to FIGS. 2 and 6, the cord 72 comprises advantageously, at one end, an igniter relay percussion 76 charged with its ignition and, at the other end, a detonation relay 78 responsible for initiating by influence the primer 18 through an opening 79 provided in barrel 20. Under these conditions, initiation of the self-destruction device 70 is effected by percussion of the igniter relay 76 by the auxiliary striker 60 carried by the cam 50 when the latter reaches its retracted position or percussion.

The operation will now be described. the priming system 5.

The parts of the priming system 5 are assembled and fixed to the body 7 of the submunition 1, so that the barrel 20 and the cam 50 are in their safety positions respective, as illustrated in Figures 1 and 2.

More specifically, the main striker 22 is screwed into nut 44 so that its tip of percussion 42 comes to engage in the notch 46 of the barrel 20. Barrel 20 armed by spring 33 is in its safe position in which the two openings 35 of the barrel 20 which communicates with the primer 18 are not axially aligned with the main striker 22 and the following explosive charge 3 the Y-Y axis of submunition 1.

The cam 50 is held in its position of security via finger 65 of barrel 20 which bears against the stop 58 of the cam 50. In these conditions, the outer edge 55 of the part front 52 of cam 50 is substantially in contact with the mask 28; and the outer edge 56 of the part rear 54 of cam 50 does not protrude at the outside of the opening 28a of the mask 28.

It is important to note that the positions of security of barrel 20 and cam 50 are such that any accident can be avoided when handling submunitions, especially during the loading phase in the carrier. Indeed, any manipulation of the submunition is not likely to cause the unscrewing the main striker 22 and as soon as the barrel 20 is kept in its safety position, it also maintains the cam 50 in its position to prevent accidental initiation of the striker self-destruction device auxiliary 60.

After the firing of the carrier and in normal operation, barrel 20 and cam 50 are kept in their respective safety positions, because the acceleration and the rotation of the machine in principle have no influence on the barrel 20 and cam 50.

At the time of unloading, the submunitions 1 are scattered, and the barrel 20 of the system priming 5 of a submunition 1 cannot pass in its arming position only after the action of an element trajectory stabilizer, such as a ribbon or parachute (not shown) and which is attached to the end of the main striker 22. The deployment of this element stabilizer causes a deceleration which, combined with the rotational movement imparted to the submunition after its dispersion, causes the striker to be unscrewed principal 22. Once the first means of lock constituted by the main striker 22 is released, the barrel 20 under the action of its spring cock 33 goes into its illustrated cocking position in Figure 4. At the start of the rotational movement of the barrel 20, his finger 65 emerges from the stop 58 of the cam 50, which has the effect of releasing the passing cam thus in its retracted position under the action of its arming spring 62. The auxiliary striker 60 comes strike the igniter relay 76 and the device of self-destruction 70 is initiated at a time which corresponds to the passage of the barrel 20 in its position of weapons.

As a result of impact on the ground or on a target of submunition 1, the resulting deceleration causes the percussion of the primer 18 by the striker principal 22. In the event of a malfunction, the initiator 18 is initiated by the self-destruction device 70 after a delay defined by the length of the cord 72.

If, following the firing of the carrier and before stripping, the main striker 22 undergoes a movement of translation as it releases the barrel 20, the latter under the action of its arming spring 33 moves towards its arming position. At the beginning of the movement of rotation of the barrel 20, his finger 65 emerges from the stop 58 of cam 50, which has the effect of releasing the cam which tends to pass into its retracted position under the action of its arming spring 62. However, the cam 50 can only rotate limited because its rear part 54 will cross the opening 28a of the mask 28 to come into contact with the coating 15 of charge of the submunition next. Concretely, the cam 50 is held in a intermediate safety position such as rotation of barrel 20 will be interrupted before the latter does not reach its arming position. Indeed, finger 64 of the barrel 20 will come into contact with the stop 59 of the cam 50, which has the effect of interrupting the movement of rotation of the barrel 20 which is thus maintained in an intermediate safety position (see Figures 9 and 10).

After release of the main striker 22, the cam 50 is released (Figures 7 and 8). In these conditions, the barrel 20 can move into its position arming and the cam 50 can move into its position retracted or percussion with device initiation self-destruction 70.

On the impact of submunition 1 on the ground or a target, the main striker 22 initiates the primer 18 and, in the event of a malfunction, the self-destruction device 70 acts at the end of the delay determined by the length of the cord 72.

In the above embodiment described, the primer holder is movable in rotation. In variant, the characteristics of the priming system according to the invention also apply in the case where the primer holder is movable in translation.

Claims (7)

1. A priming system for the explosive charge (3) of a sub-munition (1) carried on board a carrier, this system comprising :

   a main firing pin (22) able to translate,

   a mobile primer tube (20) driven by a motor element (33) from a safety position in which the primer (18) is not aligned with the firing pin (22) and the explosive charge (3) to an armed position in which this alignment has been made,

   at least two devices to lock the primer tube (20) in a safety position before the sub-munition (1) is ejected, and

   a mechanism (70) to self-destruct the sub-munition (1) after a pre-determined delay,

      characterised in that one of the locking devices is formed of a mobile cam (50) driven by a motor element (62) from a safety position in which it forms a limit stop (62) preventing the primer tube (20) from passing freely into its armed position, to a retracted position allowing the free passage of the primer tube (20), and in that it comprises two means to immobilize the cam (50) in a safety position which are released further to the ejection of the sub-munition (1), and in that said cam (50) is fitted with an auxiliary firing pin (60) which ignites a delay cord (72) when the cam (50) is in its retracted or percussion position after the sub-munition (1) has been ejected.
2. A priming system according to Claim 1, characterised in that the cam (50), in its safety position, comprises a limit stop (58) which is located on the course of movement of a finger (64) integral with the primer tube (20) to immobilize the latter in an intermediate safety position.
3. A priming system according to Claims 1 or 2, characterised in that the means to immobilize the cam (50) in its safety position comprise a finger (65) integral with the primer tube (20) and which bears on a limit stop (59) of the cam (50) when the primer tube (20) is itself in its safety position, this finger (64) retracting at the onset of the course of movement of the primer tube (20) towards its armed position.
4. A priming system according to any of Claims 1 to 3, characterised in that the means to immobilize the cam (50) in its safety position comprise the body (7) of an adjacent sub-munition on board the carrier.
5. A priming system according to any one of the above Claims, characterised in that the other means to lock the primer tube (20) in its safety position comprise the main firing pin (22).
6. A priming system according to any one of the above Claims, characterised in that the motor elements (33, 62) of the primer tube (20) and the cam (50) are respectively formed of springs.
7. A priming system according to any one of the above Claims, characterised in that the sub-munition (1) comprises a body (7) enclosing the explosive charge (3), said body (7) being topped by the priming mechanism (5), the latter comprising a body (24) in which the firing pin (22), the primer tube (20) and the cam (50) are housed, and in that the delay cord (72) of the self-destruct mechanism (70) is wound around the body (24) of the priming system (5).

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