EP0687888B1 - Firing device for a fuse head type pyrotechnic charge, in particular for a hand grenade having three ways of functioning - Google Patents

Description

The technical sector of the present invention is that of devices for igniting a pyrotechnic charge of the type igniter plug, in particular for hand grenade, comprising a pyrotechnic chain initiated in a conventional manner by a striker controlled by the movement of a spoon associated with a pin.

This firing device must incorporate the requirements of safety, reliability and low cost. Especially, storage and transport security must be ensured by interruption of the pyrotechnic chain.

This device must also allow the operator to select one of the three load operating modes following pyrotechnics: fusing or percussive mode, or hard-hitting mode.

It is necessary that all the constituent elements can be part of a manufacturing process automated. Their assembly must be designed for a complete robotization.

In this technical field, several achievements have been proposed.

Patent FR 2,517,048 describes an igniter plug for hand grenade having three modes of operation and one safe storage and operation by interrupting the pyrotechnic chain and blocking of strikers. This cap has two pyrotechnic chains having a common part, one being associated with a first striker specific to fused operation and the other chain cooperating with a second striker for impactful operation. The selection of selected operation of the grenade is carried out from a outer ring provided with a lug on which a stop comes plate animated by a movement with a timer rotation. This tray also conditions the alignment of the pyrotechnic train which is obtained after removing the pin and after a delay determined by the timer.

This igniter plug has several drawbacks. In particular, it has two non-aligned main strikers between them cooperating with two pyrotechnic chains, which leads to complexities of manufacturing and operation.

Another disadvantage lies in the association of the alignment of the pyrotechnic train and the arming of the modes operating with a timer, which may affect the safety and functional reliability of such a plug igniter.

A fire, kinetic impact, or near explosion, may cause accidental tearing of the pin followed by the rotation of the plate, causing a pyrotechnic alignment irreversible of the chain.

In addition, the striking-fusing function corresponds to self-destruction of the grenade in the event of absence of percussion, and not to a fusing function triggered by the function impactful.

We also know the patent FR 2,458,790 describing a multipurpose igniter plug with launch safety. This cap, very close to that described in the previous patent, has four operating possibilities and has two corresponding independent non-aligned main strikers each with different operating modes, a selector consisting of two rotating discs controlled by a movement of watchmaking, these participating in storage security and launch. It also has an impact detector associated with one of the strikers who takes an armed position directly after ejecting the spoon, requiring the presence of launch security.

We find here most of the disadvantages stated more high. In particular, the use of a clockwork mechanism, may have failures, to check alignment of the pyrotechnic chain and also ensuring the safety of the shoot.

Regarding the striking-fusing mode, the fusing function is not triggered by the percussive function.

We also know the patent FR 2,682,471 which describes a safety of storage by interruption of pyrotechnic chain for an igniter plug. This interruption is carried out by a pivoting element having a radial opening, placed between the delay module and priming composition. The rotation of this element, caused indirectly by the ejection of the spoon, automatically causes the final alignment of the pyrotechnic chain, especially in an aggressive environment.

Patent FR 2,465,189 according to the preamble of claim 1, also shows an igniter plug for grenade comprising a pyrotechnic chain interruption by a rotary member controlled by a delay mechanism by escapement of glass beads, allowing alignment definitive of the chain after a predetermined time after priming the chain.

The operating principle of chain interruptions pyrotechnics described in these two patents as well as in the patents mentioned above, has the major drawback cause an automatic and irreversible alignment of the chain, in storage in an aggressive environment.

In addition, during the possible failure of a single element essential locking, can intervene by accident without human presence (fire, explosion, impacts), inevitably the firing procedure is started.

The object of the present invention is to remedy the disadvantages mentioned above, by proposing a device for ignition of a pyrotechnic charge, of the igniter plug type applicable in particular, but not exclusively, to grenades hand, offering increased safety during storage, transport and shooting, high functional reliability, low manufacturing and assembly costs perfectly within the framework of an industrial manufacturing of series.

Another object of the invention is to ensure the security of storage and transport in primed strikes, by interruption of the pyrotechnic chain.

The invention also aims to provide a plug igniter directly adaptable to different types of gear pyrotechnics and more particularly on several models of hand grenades (offensive, defensive, smoke tear or exercise), while retaining conventional means of placing implemented, such as the spoon and pin combination.

Another purpose is to allow the user to select one of the three modes from the igniter plug operating modes of the following pyrotechnic charge: mode fusant, or percussive, or percussive-fusant.

To do this, the invention relates to a device for ignition of a pyrotechnic charge, of the igniter plug type in particular for hand grenade, comprising, housed in a bore axial in the body of the cap, a chain pyrotechnic in two parts upstream and downstream, the downstream part being fired by an axial striker placed between the two parts of the chain and associated with control means cooperating with a locking means. This device includes mechanical means for controlling the striker, which are inserted between the upstream part of the chain and this one for drive the striker in an axial and rotary movement around its axis, under the pressure of the gases generated by the initiation of the upstream part.

Preferably, the mechanical means for controlling the striker cooperate with a guide member engaged in a ramp at the bore of the plug body.

Preferably, the striker control means cylindrical hollow consist of a spring and a piston sliding axially with respect to the central bore, housed in a fixed cylindrical internal body containing the upstream part of the pyrotechnic chain, this body being partially fitted in the striker.

The means of locking the striker with the internal body may consist of a ball protruding into a housing of the body and allowing the striker to move from a position safety initial, where the piston keeps the ball in engagement in an internal circular groove of the striker, at a position armed, after axial displacement of the piston, in which the ball positioned opposite an external circular groove of the piston comes out of the internal circular groove of the striker and releases it.

Preferably, the guide member consists of a ball protruding into the central bore engaged in the ramp produced on the external wall of the striker, this ramp comprising a longitudinal part extended by a part helical, so as to make a first axial movement the striker followed by a second movement, both rotary and axial of the same striker.

The device may include a module for neutralizing the striker, arranged between the latter and the downstream part of the pyrotechnic chain.

This cylindrical neutralization module can present three sets of lights of different lengths distributed around the periphery of the module, for housing at minus a lug of the striker.

The striker can have three distributed external pins at 120 ° on its periphery and placed opposite one of the three series of lights equally distributed on the module for carry out either neutralization of storage and transport safety position of the striker, i.e. neutralization functional in its armed position, i.e. firing of the downstream part of the chain.

Preferably, the device comprises a module self-destructing comprising a gas generating composition contained in the piston and initiated by the upstream part of the chain, an exhaust vent made in the piston and placed, after displacement of the piston, opposite a fixed axial scroll to the striker, to drive under the effect of the control means a rotary and axial movement of the latter followed by the setting fire in the downstream part of the chain.

The gas-generating composition contained in the piston may consist of a delayed composition associated with a reinforcing composition.

According to a preferred embodiment, the setting device according to the invention, comprising an axial element of interruption of the pyrotechnic chain placed in the part downstream of the chain housed in a cylindrical case, includes mechanical means for driving the axial element of interruption activated by the only rotation of the head of the igniter plug, allowing alignment and manual misalignment of the chain.

This interrupting element may consist of a cylinder drilled with an axial hole, fixed to an alignment barrel rotated by mechanical means from a position radial to an axial position of the cylinder and vice versa.

Mechanical means for rotating the barrel may consist of a movable cylindrical internal part in rotation partially housed in the case and connected by its lower end of the barrel, its upper end being driven by the rotation of the body and the head of the cap.

According to a first embodiment, the barrel is provided of a post engaged in a helical groove made in the cylindrical case, ensuring a 90 ° rotation of the cylinder.

According to a second embodiment, the barrel comprises teeth engaged in a rack of the case to ensure a 90 ° rotation of the cylinder.

Preferably, the downstream part of the pyrotechnic chain successively comprises a percussion primer, a charge in lead azide, a hexogen ignition relay, the element interruption cylinder then a main relay in hexogen.

According to a preferred embodiment, the cylinder also contains a relay load intermediate in secondary explosive of the hexogenic type.

The device for igniting a pyrotechnic charge according to the invention applied to a three-function igniter plug allowing a fusing, percussive, or percussive-fusing operation of the load, of the type comprising a mode selector of operation, an impact detector module and a module timer, is preferably provided with a selector consisting by the cylindrical outer wall of the cap head, mobile rotating around the cylindrical body of the plug pierced by the central bore.

The timer module secured to the selector can include a mechanical oscillator regulating the rotation of at least one toothed wheel meshed in at least one rack axial fixed on the external wall of the striker, to produce a percussion delay in percussive-fusing mode.

According to an alternative embodiment, the external wall of the striker has four parallel length racks each corresponding to percussion delays of one second, seven tenths, four tenths and one tenth of second.

Preferably, an impact detector module will be used omnidirectional with adjustable sensitivity, for impactful mode and the striking-fusing mode, housed in an axial bore of the body cylindrical of the cap, comprising a master cylinder associated with a first spring, a counter-cylinder associated with a second spring, a transverse detection ball inserted between the master cylinder and counter cylinder, two balls of locking and unlocking of the module controlled by the axial movement of the striker and another ball of functional locking and unlocking of the module preventing or authorizing its operation by the action of the selector.

Preferably, the module's transverse detection ball impact detector consists of a dense material of the type tungsten.

Preferably, the selector has in the safety position means prohibiting the extraction of a locking pin a spoon and an upstream striker controlling the firing of the upstream part of the chain.

• en position de sûreté, la goupille est verrouillée, le train pyrotechnique est interrompu par l'élément maintenu en position radiale, le percuteur, dont les trois ergots sont en regard des trois lumières courtes de sûreté, est verrouillé par la bille en prise dans la rainure circulaire interne du percuteur, la roue dentée du module temporisateur se trouve à l'écart des crémaillères du percuteur, et le module détecteur d'impact est verrouillé par les deux billes bloquant respectivement le maítre-cylindre et le contre-cylindre sous l'action du percuteur en position initiale, de plus la bille de verrouillage fonctionnel maintenue par le sélecteur bloque également le maítre-cylindre,
• une première rotation de 90° du sélecteur, correspondant au fonctionnement fusant de la charge, provoquant successivement, le déverrouillage de la goupille autorisant son extraction, l'alignement du train pyrotechnique par rotation de 90° de l'élément d'interruption, et la rotation relative du module de neutralisation par rapport au percuteur en plaçant les trois lumières plus longues du module en regard des trois ergots du percuteur correspondant à la position de neutralisation fonctionnelle du percuteur, les modules temporisateur et détecteur d'impact restant inactifs,
• une deuxième rotation de 90° du sélecteur, correspondant au fonctionnement percutant, provoquant de plus, la libération de la bille de verrouillage fonctionnel du module détecteur d'impact, celle-ci venant se loger dans une rainure circulaire interne du sélecteur pour rendre actif ce module,
• une troisième rotation de 90° du sélecteur, correspondant au fonctionnement percutant-fusant, provoquant de plus, l'alignement de la roue dentée du module temporisateur avec la première crémaillère du percuteur correspondant à un retard de percussion d'une seconde, le module détecteur d'impact restant actif.

According to a preferred operating mode, the rotary selector occupies an initial safety position and takes, by successive rotations of 90 °, at least three different positions, each corresponding to one of the operating modes:

• in the safety position, the pin is locked, the pyrotechnic train is interrupted by the element maintained in the radial position, the striker, the three pins of which face the three short safety lights, is locked by the ball engaged in the internal circular groove of the striker, the toothed wheel of the timer module is located away from the racks of the striker, and the impact detector module is locked by the two balls blocking respectively the master cylinder and the counter-cylinder under the action of the striker in the initial position, in addition the functional locking ball held by the selector also blocks the master cylinder,
• a first rotation of 90 ° of the selector, corresponding to the fusing operation of the load, causing successively, the unlocking of the pin authorizing its extraction, the alignment of the pyrotechnic train by rotation of 90 ° of the interruption element, and the relative rotation of the neutralization module with respect to the striker by placing the three longer lights of the module opposite the three lugs of the striker corresponding to the functional neutralization position of the striker, the timer and impact detector modules remaining inactive,
• a second 90 ° rotation of the selector, corresponding to impactful operation, causing moreover, the release of the functional locking ball of the impact detector module, the latter being housed in an internal circular groove of the selector to make this active module,
• a third 90 ° rotation of the selector, corresponding to the striking-fusing operation, causing moreover, the alignment of the toothed wheel of the timer module with the first rack of the striker corresponding to a percussion delay of one second, the detector module impact remaining active.

According to an operating variant, the selector being in striking-fusing position, three additional rotations successive in the same direction of the selector causing alignment of the timing module gear wheel with respectively, the second rack of the striker corresponding to a percussion delay of seven tenths, the third striker rack corresponding to a delay of percussion of four tenths and the fourth rack of the striker corresponding to a percussion delay of one tenth second.

According to another operating variant, in position impactful and impactful fuse of the selector and in the absence of impact sensor module operation, the module of self-destruction associated with the striker control means cause the ignition of the downstream part of the chain followed of the explosion of the object.

An advantage of an igniter plug according to the invention resides in the compactness of its structure and the modularity of its constituent elements, significantly simplifying the conditions of shooting and the manufacturing stages encountered during a largely automated production.

This igniter plug has several operating modes offers optimized shooting and storage security. In particular, the interruption element of the pyrotechnic chain judiciously arranged within the downstream part thereof, is independent of the environment for better efficiency in case of accidental initiation of the upstream part of the chain, during transport or storage of the associated plug to the pyrotechnic charge.

This interrupt element can only be moved by voluntary operator intervention. It follows that purely manual train alignment and misalignment pyrotechnic, cannot result from the conjunction of elements aggressive exteriors.

This has the advantage of allowing storage in all safety of the igniter plug mounted on a hand grenade by example of a complete hit, which is not the case currently with existing igniter plugs.

Another advantage is the positioning in the center of the main load of the main initiation relay, ensuring thus an isotropic detonation of the pyrotechnic charge.

Other characteristics and advantages of the invention will appear in the detailed, nonlimiting description of a embodiment of the invention.

• la figure 1 représente une vue en coupe axiale d'un bouchon allumeur trois fonctions selon l'invention, en position de sûreté,
• la figure 2 représente une vue à l'échelle agrandie, suivant AA de la figure 1 du module de neutralisation associé au percuteur en position de stockage ou de transport,
• la figure 2A représente une vue selon la figure 1 du module de neutralisation seul,
• la figure 3 représente une vue latérale du percuteur, montrant à l'échelle agrandie, le trajet relatif de l'organe de guidage dans la rampe longitudinale et hélicoïdale participant au déplacement du percuteur,
• la figure 4 représente une vue latérale du percuteur associé au module temporisateur,
• la figure 5 représente une vue en coupe axiale d'une grenade à main offensive-défensive équipée d'un bouchon allumeur selon l'invention, montrant plus particulièrement la partie aval de la chaíne pyrotechnique avec son élément d'interruption, en position de sûreté, ainsi que les moyens de verrouillage de la goupille,
• la figure 6 montre, à l'échelle agrandie et suivant la figure 5, l'élément d'interruption du train pyrotechnique, selon un premier mode de réalisation,
• la figure 7 montre une vue identique à la figure 6, d'un second mode de réalisation de cet élément,
• les figures 8 et 8A représentent une vue de dessus du sélecteur avec indication des différents modes de fonctionnement, montrant les moyens de verrouillage de la goupille en position de sûreté,
• les figures 9, 9A, 9B et 9C sont des vues en coupe radiale selon BB de la figure 1 respectivement, au niveau de l'étui fixe, du sélecteur, du corps du bouchon et de la partie haute de la pièce interne renfermant le module de neutralisation,
• les figures 10, 10A, 10B, 10C et 10D représentent une vue schématique partielle selon la figure 1, montrant les différentes positions de certaines parties mobiles respectivement en position, de sûreté, d'alignement du train pyrotechnique, fusant, percutant et percutant-fusant,
• les figures 11, 11A et 11B représentent une vue partielle selon la figure 1, illustrant les déplacements du piston et du percuteur jusqu'à la position armée de ce dernier, en mode de fonctionnement percutant-fusant,
• la figure 12 représente une vue selon les figures 11 à 11B, après mise à feu par le fonctionnement du module détecteur d'impact,
• la figure 13 représente une vue selon les figures 11 à 11B, après mise à feu par le fonctionnement du module d'autodestruction.

This description will be made with reference to the accompanying drawings, among which:

• FIG. 1 represents a view in axial section of a three-function igniter plug according to the invention, in the safety position,
• FIG. 2 represents a view on an enlarged scale, along AA of FIG. 1 of the neutralization module associated with the striker in the storage or transport position,
• FIG. 2A represents a view according to FIG. 1 of the neutralization module alone,
• FIG. 3 represents a side view of the striker, showing on an enlarged scale, the relative path of the guide member in the longitudinal and helical ramp participating in the movement of the striker,
• FIG. 4 represents a side view of the striker associated with the timer module,
• 5 shows an axial sectional view of an offensive-defensive hand grenade equipped with an igniter plug according to the invention, showing more particularly the downstream part of the pyrotechnic chain with its interrupting element, in the safety position , as well as the locking means of the pin,
• FIG. 6 shows, on an enlarged scale and according to FIG. 5, the element for interrupting the pyrotechnic train, according to a first embodiment,
• FIG. 7 shows a view identical to FIG. 6, of a second embodiment of this element,
• FIGS. 8 and 8A represent a top view of the selector with indication of the different operating modes, showing the means for locking the pin in the safety position,
• Figures 9, 9A, 9B and 9C are views in radial section along BB of Figure 1 respectively, at the fixed case, the selector, the body of the plug and the upper part of the internal part containing the module neutralization,
• Figures 10, 10A, 10B, 10C and 10D show a partial schematic view according to Figure 1, showing the different positions of certain moving parts respectively in position, safety, alignment of the pyrotechnic train, fusing, striking and striking-fusant ,
• FIGS. 11, 11A and 11B represent a partial view according to FIG. 1, illustrating the displacements of the piston and of the striker to the armed position of the latter, in percussion-fusing operating mode,
• FIG. 12 represents a view according to FIGS. 11 to 11B, after firing by the operation of the impact detector module,
• FIG. 13 represents a view according to FIGS. 11 to 11B, after firing by the operation of the self-destruction module.

Referring to Figures 1 to 3 we see an igniter plug three functions of substantially cylindrical shape comprising at its lower part a case 26 provided with an external thread to adapt the cap on a hand grenade for example, no represented. On this lower part, is mounted mobile in rotation the main part of the cap surmounted by the head of the plug comprising conventional means for initiating a pyrotechnic chain such as a pin 34 and a spoon 22 controlling an upstream striker 29. The present invention does not relate not on these known conventional means.

The main part of the cap includes three pieces hollow cylindrical 23, 24 and 25 superimposed coaxial and movable in rotation with respect to each other. She has two axial bores 2 and 37. Central bore 2 is extends into the fixed case 26 screwed into the grenade.

• un corps interne 1, fixé à la pièce cylindrique 24, présentant une partie supérieure pleine munie d'un logement central cylindrique contenant une partie amont 3 d'une chaíne pyrotechnique en deux parties, et une partie inférieure creuse,
• une amorce 3a, un retard pyrotechnique 3b et une charge renforçatrice 3c génératrice de gaz, constituant la partie amont 3 de la chaíne,
• un piston cylindrique 5 creux coulissant axialement qui présente une rainure circulaire 5d externe et un évent 5c axial d'échappement des gaz à sa partie inférieure, le piston étant maintenu en position haute par un ressort 6 et ces deux éléments étant logés dans la partie inférieure creuse du corps 1,
• une composition génératrice de gaz comprenant une composition retard 5a associée à une composition renforçatrice 5b, contenue dans le piston 5,
• un percuteur 7 cylindrique creux présentant en coupe axiale la forme d'un U, mobile en translation axiale et en rotation autour de son axe par rapport au corps interne fixe 1 partiellement contenu dans le percuteur,
• une bille 8 de verrouillage et déverrouillage du percuteur avec le corps 1, faisant saillie dans un logement de la partie inférieure de ce corps; en position haute du piston, la bille prend appui d'une part sur la paroi externe de ce dernier et est en prise dans une rainure circulaire interne 7f du percuteur d'autre part,
• un module de neutralisation 20 (figure 2) du percuteur disposé sous ce dernier et solidarisé avec la pièce cylindrique 25, est constitué d'un cylindre creux muni à sa périphérie de trois séries de lumières 20a, 20b et 20c axiales de longueurs différentes réparties à 120°; une première série comprenant trois lumières courtes 20a de neutralisation de stockage et de transport, une deuxième série comprenant trois lumières 20b plus longues de neutralisation fonctionnelle et une troisième série comprenant trois lumières 20c débouchantes laissant passer librement le percuteur.

In this central bore 2 made in the cylindrical part 24 are mounted from top to bottom:

• an internal body 1, fixed to the cylindrical part 24, having a solid upper part provided with a cylindrical central housing containing an upstream part 3 of a pyrotechnic chain in two parts, and a hollow lower part,
• a primer 3a, a pyrotechnic delay 3b and a reinforcing charge 3c generating gas, constituting the upstream part 3 of the chain,
• an axially sliding cylindrical piston 5 which has an external circular groove 5d and an axial gas exhaust vent 5c at its lower part, the piston being held in the high position by a spring 6 and these two elements being housed in the lower part hollow body 1,
• a gas-generating composition comprising a retarding composition 5a associated with a reinforcing composition 5b, contained in the piston 5,
• a hollow cylindrical striker 7 having in axial section the shape of a U, movable in axial translation and in rotation about its axis relative to the fixed internal body 1 partially contained in the striker,
• a ball 8 for locking and unlocking the striker with the body 1, projecting into a housing in the lower part of this body; in the high position of the piston, the ball bears on the one hand on the external wall of the latter and is engaged in an internal circular groove 7f of the striker on the other hand,
• a neutralization module 20 (FIG. 2) of the striker disposed under the latter and secured to the cylindrical part 25, consists of a hollow cylinder provided at its periphery with three series of axial lights 20a, 20b and 20c of different lengths distributed at 120 °; a first series comprising three short lights 20a for neutralizing storage and transport, a second series comprising three longer lights 20b for functional neutralization and a third series comprising three open lights 20c allowing the striker to pass freely.

The lower end of this bore 2 communicates with a coaxial bore of the fixed case 26, containing the downstream part 4 of the pyrotechnic chain.

The lower part of the striker 7 has three lugs 7e exteriors distributed at 120 ° on its periphery, suitable for housing in the three sets of lights 20a, 20b and 20c of the module neutralization. On the inner face of this lower part of the striker 7 is fixed an axial scroll 7d communicating with the exhaust vent 5c of the piston 5 in the low position and driving the striker in rotation under the effect of gases produced by the combustion of the pyrotechnic composition 5a and 5b contained in the piston 5.

This neutralization module also includes a lug 21 axial neutralization indication, protruding at the outside of the module through a recess 26a of this last when one of the three pins 7e of the striker is in support on its upper part. In the extended position, this lug 21 constitutes a stop preventing the relative rotation of the module 20 and the selector 23 relative to the fixed case 26, and indicating to the operator the neutralization position occupied by the striker.

A ramp 7a, 7b (Figure 3) is dug in the wall cylindrical external of the striker 7. It comprises a part longitudinal 7a extended by a helical part 7b in which is engaged a guide member consisting of a ball 9 movable in rotation in an open housing made in the body 24 of the plug and protruding into the bore central 2 of the plug.

In this FIG. 3, there is shown in broken lines, the different positions taken by the ball 9 in the ramp longitudinal 7a and helical 7b during the movement of the striker. This ball successively occupies positions 9a, 9b, 9c and 9d after respectively a first axial displacement of the striker, a second rotary and axial movement corresponding to the armed position of the striker, a third displacement caused by the action of the self-destruct module, a fourth displacement leading to percussion of self-destruction or of the fused operating mode.

Note that the configuration of the guide member and the ramp described above is not limiting, and that a variant where the ramp would be dug in the body 24 of the plug at the bore and the guide placed on the cylindrical wall of the striker 7 by example, is also covered by the present invention.

Four axial racks 7c, 7c2, 7c3 and 7c4 parallel and of different lengths are fixed on an area of the wall cylindrical external of the striker diametrically opposite to that comprising the ramp described above. In operating mode hard-hitting charge, as will be described later, these racks ensure percussion delays of one second, seven tenths, four tenths and one tenth of second (Figure 4).

A timer module is placed, through a manhole made in the body 24 of the plug, in the external part cylindrical 23 forming the head of the plug used for select the different operating modes of the machine pyrotechnic. This timer module, integral with the selector 23 by any known means, is rotated by the latter around the striker, to align with one of the four axial racks of the striker in striking-fusing mode.

This purely mechanical timer module includes a oscillator 19 regulating the rotation of one or more wheels teeth 18 that can mesh in one of the four racks, depending on the duration of the percussion delay chosen by the operator from selector 23.

An omnidirectional sensitive impact detector module adjustable is mounted in the second axial bore 37 which can have a diameter equal or not to that of the central bore 2. This second bore 37 is formed in the body 24 of the plug short distance from the central bore 2.

• un maítre-cylindre 10 associé à un premier ressort 11 en appui sur le fond de l'alésage 37 d'une part et sur la partie inférieure du maítre-cylindre,
• un contre-cylindre 12 associé à un second ressort 13 en appui sur l'extrémité supérieure de l'alésage 37 d'une part et sur la partie supérieure du contre-cylindre,
• une bille 14 en tungstène de détection transversale, intercalée entre le maítre-cylindre et le contre-cylindre, mobile radialement dans un logement interne du corps 24 du bouchon et du sélecteur 23,
• deux billes 15 et 16, mobiles radialement dans deux logements de la partie du corps 24 située entre les deux alésages 2 et 37 et chacune faisant saillie dans ces deux alésages, verrouillant en position haute du percuteur 7 et déverrouillant après déplacement axial de celui-ci respectivement, le maítre-cylindre 10 et le contre-cylindre 12,
• une bille 17, mobile radialement dans un logement du corps 24, assurant le verrouillage fonctionnel du module sous l'action du sélecteur 23 qui la maintient en prise dans une gorge du maítre-cylindre 10, et le déverrouillage fonctionnel autorisant le fonctionnement du module après une rotation du sélecteur autour du corps 24 permettant à cette bille de s'échapper de la gorge du maítre-cylindre pour se loger dans une rainure circulaire interne 23b du sélecteur.

This impact detector module, used in percussion mode and in percussion-fusing mode, includes:

• a master cylinder 10 associated with a first spring 11 bearing on the bottom of the bore 37 on the one hand and on the lower part of the master cylinder,
• a counter-cylinder 12 associated with a second spring 13 bearing on the upper end of the bore 37 on the one hand and on the upper part of the counter-cylinder,
• a ball 14 made of tungsten transverse detection, interposed between the master cylinder and the counter cylinder, movable radially in an internal housing of the body 24 of the plug and of the selector 23,
• two balls 15 and 16, radially movable in two housings of the part of the body 24 located between the two bores 2 and 37 and each projecting in these two bores, locking in the high position of the striker 7 and unlocking after axial displacement thereof respectively, the master cylinder 10 and the counter cylinder 12,
• a ball 17, radially movable in a housing of the body 24, ensuring the functional locking of the module under the action of the selector 23 which keeps it engaged in a groove of the master cylinder 10, and the functional unlocking allowing the operation of the module after a rotation of the selector around the body 24 allowing this ball to escape from the groove of the master cylinder to be housed in an internal circular groove 23b of the selector.

In the high position of the striker 7, the locks of these two elements of the module are provided by the striker which keeps each of the balls 15 and 16 engaged in the groove master cylinder and counter cylinder. The master cylinder 10 is in contact with ball 9 and maintains engagement in the ramp 7a, 7b of the striker. This master cylinder has two notches 10a allowing, after axial displacement of the latter caused by a shock longitudinal or transverse, the exit of the ball 9 from the ramp releasing the striker.

The selector 23 constituted by the cylindrical head of the plug has at its lower part an elastic lock 23a which just snaps into a circular notch in the fixed case 26. On the periphery of the upper part of the selector 23 (FIG. 8A) are arranged four marks principal correspondents for security positions, Fusing, impactful and impactful-fusing operation. The operator accesses each of these four marks by rotation successive 90 °. In the striking-fusing position, the selector has three secondary references, accessible by rotation successive 20 ° for example, corresponding to the different percussion delays described above.

An external element around the upper part of the case 26 has a circular rib 26e (Figures 5 and 8) trapping, using the elastic lock 23a of the selector safety position, part of a ring 34a connected to the pin 34, to prevent the extraction of the latter only when the selector is in the safety position.

In the fixed cylindrical case 26 screwed into the grenade, is climb the downstream part 4 of the pyrotechnic chain. This part downstream 4 comprises from top to bottom: a percussion primer 4a, a charge 4b in lead azide, a priming relay 4c in hexogen, a cylinder element 27 for interrupting the chain then a main 4d hexogen relay (Figures 5 to 7).

This element 27 of interruption or misalignment of the train pyrotechnic consists of a cylinder pierced with an orifice axial and preferably containing an intermediate relay load as a secondary explosive of the hexogenic type. It is fixed by everything known means on a cylindrical barrel 28 driven in rotation by mechanical means from a radial position to a position axial of the element and vice versa.

These mechanical means, activated by rotation only manual of the selector 23 constituted by the head of the plug, have an internal cylindrical part 25 the part of which lower 25a is housed in the case 26 and the upper part containing the neutralization module is rotated by the body 24 of the cap covered by the selector 23.

According to a first embodiment (FIG. 6), these means mechanical include a helical groove 31 made in the case 26 associated with a pin 30 of the movable barrel 28 in rotation in the lower end 25a of the internal part 25, so as to rotate the element 90 ° 27 by a joint 45 ° rotation of the body 24 and the selector, in the initial safety position. Beyond 45 °, the upper part of part 25 is locked with the case fixed 26, in order to keep the alignment of the pyrotechnic train for the three operating modes. The return to position of safety of selector 23 unlocks part 25 of case 26 and causes the pyrotechnic train to be misaligned by returning to radial position of the element 27.

According to a second embodiment (Figure 7), the assembly helical groove 31 associated with the tenon 30 is replaced by a gear wheel 32 of barrel 28 geared into a rack 33 case 26 circular to ensure alignment and misalignment of the pyrotechnic train by 90 ° rotation of the interrupting element 27.

The operation of the firing device according to the invention is as follows.

The igniter plug being mounted in the safety position on a hand grenade type pyrotechnic device for example, the operator chooses one of the three operating modes in turning the head 23 of the cap by hand around the case fixed 26 screwed on the machine.

In the initial safety position, the pin 34 cannot be removed, the element 27 in the radial position interrupts the chain pyrotechnic, the three lugs 7e, of the striker 7 locked in high position, are opposite the three short lights 20a, and the timer and impact detector modules are inactive (Figure 10).

Provided that the neutralization indication lug 21 has not entered inside the recess 26a, the operator can rotate the selector 23 in one direction only by exerting pressure on the elastic lock 23a snapped into the circular notch of the fixed case 26, to select the desired operating mode.

During the angular displacement from 0 ° to 45 ° of the selector 23, the three cylindrical parts 23, 24 and 25 can rotate simultaneously with respect to the fixed case 26, thanks to two cams 23d and 24b, forming part of the respective ends of the parts 23 and 24, provided with two tenons 23c and 24a sliding in corresponding grooves 26b and 26c of the case (Figures 9 at 9B).

At the 45 ° position, not indexed, of the selector, the alignment of the pyrotechnic train is achieved (Figure 10A) by rotation of 90 ° of the interrupting element 27 produced by the rotation of internal part 25, the latter is then locked with case 26 to keep the alignment of the train during the selection of operating modes. This lock is produced by an elastic lug 25b, located at the end of the part 25, sliding in the groove 26d of the case 26, where it locks at the end of the groove (Figures 9 and 9C).

It should be noted that the misalignment of the pyrotechnic train can again be done by reverse rotation and back in safety position.

During the angular displacement from 45 ° to 90 °, the two cylindrical parts 23 and 24 remain integral and rotate simultaneously with respect to the locked internal part 25.

It will be noted that the striker 7 is linked in rotation with the cylindrical part 24 by the ball 9 engaged in the ramp 7a, 7b thereof.

At the 90 ° position, corresponding to the operating mode fusant (Figure 10B), the rotation of the part 24 and therefore of the striker 7 placed the three lugs 7e of the latter facing the three longer lights 20b of functional neutralization, the impact sensor module remains blocked by the ball functional lock 17 held in the groove of the master cylinder 10 by the selector, and the module timer remains away from the racks 7c of the striker.

In this position, the operator can extract the pin 34 by pulling on the ring 34a released by the erasure of the circular groove 26e of the case 26, the part cylindrical 24 being locked with the upper part of the internal part 25 by snap-fastening at the rib 26c and of the elastic cam 24b associated with its stud 24a.

At the 180 ° position, corresponding to the operating mode impactful (Figure 10C), the functional locking ball 17 comes out of the groove of the master cylinder 10 and is housed in the internal circular groove 23b of the selector to activate the impact detector module.

In this position, as in the previous position, the timer module stays away from the racks 7c of the striker. The part 24 is locked on the case 26 by a lug 24c in the groove 26f of the case.

During the angular displacement from 180 ° to 270 °, the selector 23, associated with the timer module, revolves around the body 24 of the plug.

At position 270 °, corresponding to the operating mode hard-hitting (figure 10D), the gear wheel 18 of the module timer is aligned with the first rack 7c of the striker corresponding to a percussion delay of one second, and the functional locking ball 17 remains free for leave the impact detector module active.

The other angular positions of the selector which can for example be 300 °, 320 ° and 340 ° correspond respectively to the alignment of the toothed wheel 18 with the racks 7v2, 7v3, and 7v4 for percussion delays of seven tenths, four tenths and one tenth of a second. In these last three positions, the impact detector module also remains active. Each of these four positions is indexed by cam 23c.

The operation of the device is described below. hard-hitting mode mounted on a hand grenade (Figures 11 11B and 12).

Differences in operation according to the other two modes can easily be deduced from it.

We place ourselves here in the configuration relating to this mode particular operating, determined by position corresponding to the selector, described above.

The operator extracts pin 34 and launches the grenade. The spoon 22 releases the upstream striker 29 which strikes the primer 3a of the upstream part 3 of the pyrotechnic chain (Figure 11). The following actions follow one another.

The combustion of the pyrotechnic delay 3b ignites the charge reinforcer 3c which generates gases causing displacement axial of the piston 5 compressing the spring 6.

As soon as the external circular groove 5d of the piston 5 arrives opposite the ball 8, it releases the striker cylinder 7 which then moves axially under the action of spring 6 compressed.

The longitudinal part 7a of the striker ramp slides in front of ball 9 until it meets the game helical 7b of the ramp (Figure 11A).

The helical shape of this part of the ramp prints on striker cylinder rotated a few degrees. AT the end of the helical part 7b, the striker stops, retained by the ball 9 (Figure 11B).

Note that the striker 7 forced by the part helical ramp with one rotation, allows the three 7th pins of the striker to move away from the three lights 20b long functional neutralization of the module neutralization, to position itself next to the three lights 20c outlets, thus authorizing effective arming of the device. This original trick allows you to both control the presence of the ball 9 guiding the striker, as well as the triggering of the percussion, and the integrity of the impact detector module. If one had failed, the striker would have dived into neutralization lights functional 20b.

In its movement, the striker released the two balls 15 and 16 and thus unlocked the impact detector module.

A longitudinal impact, producing an axial displacement of the master cylinder 10, ball 14 and counter cylinder 12 assembly, or transverse, radially moving the ball 14, drives necessarily the axial displacement of the master cylinder 10 of which one of the two notches 10a allows the ball 9 to come out of the helical part 7b of the ramp causing the release of the striker (Figure 12).

In its movement towards the downstream part 4 of the chain pyrotechnic, the striker is delayed by the module timer. Indeed, the rack 7c of the striker (or one of the shorter racks 7v2, 7v3 and 7v4, depending on the selected impact delay) comes into contact with the wheel toothed 18 which strongly brakes the striker (Figures 11B and 12).

After a delay, depending on the length of the rack, the striker is finally released and will ignite the downstream part 4 of the chain by striking the primer 4a.

If the impact detector module does not release the ball 9 in the self-destruct module contained in the piston 5 takes over (figure 13).

Indeed, the propellant charge 3c ignited the composition delay 5a. At the end of combustion, the composition reinforcer 5b generates gases, the flow of which through the volute 7d forces the striker to a new rotation. The upper end of the helical part 7b of the ramp then presents itself to the ball 9 which disappears (FIG. 3).

This additional striker rotation has misaligned the rack 7c with the toothed wheel 18 of the timer module so that the percussion of self-destruction is instantaneous.

Regarding operation in percussive mode, it is identical to the striking-fusing mode, however the rotation of 180 ° of the selector 23 leaves the racks of the striker at away from the timer module.

Regarding the fuse mode operation, it is similar to percussive-fusing mode, however 90 ° rotation of the selector 23 also leaves the racks of the striker at away from the timer module and does not release the ball from functional locking 17 of the impact detector module which therefore remains inactive, so that the self-destruction of the grenade is inevitable.

Claims (27)

1. A device for firing a pyrotechnic load, of the firing tap type notably for hand grenades, comprising a two-part (3, 4) upstream and downstream pyrotechnic chain, inserted in an axial bore (2) drilled in the tap body (24), the part downstream (4) being fired by an axial firing pin (7) located between both parts of the chain and combined with control means cooperating with locking means. This device comprises mechanical means (5, 6) of controlling the firing pin, which are interposed between the upstream section of the chain and the firing pin itself to cause the firing pin (7) to move axially and rotate around its axis, under the pressure of the gas generated by the activated part (3) upstream of the pyrotechnic chain.
2. A device according to claim 1, characterised in that the mechanical means of control (5, 6) of the firing pin cooperate with a guiding means (9) set in a ramp (7a, 7b) at the bore (2) level of tap body (24).
3. A device according to claim 2, characterised in that the control means of the hollow cylindrical firing pin (7) comprise a spring (6) and piston (5) sliding axially in relation to the central bore (2), housed in a fixed cylindrical internal body (1) containing the upstream section of the pyrotechnic chain, this body being partly fitted into the firing pin (7).
4. A device according to claim 3, characterised in that the means locking firing pin (7) with the internal body (1) can comprise a ball (8) projecting beyond the housing of body (1) and enabling the firing pin to go from an initial safe position where the piston (5) keeps the ball set in an internal circular groove (7f) of the firing pin, to an armed position, after axial displacement of the piston in which ball (8) positioned opposite an external circular groove (5d) of the piston goes out of the internal circular groove (7f) of the firing pin and releases it.
5. A device according to claim 4, characterised in that the guiding means comprises a projecting ball (9) in the central bore 2 set in the ramp made on the external wall of the firing pin, this ramp comprising a longitudinal section (7a) prolonged by a helicoid section (7b), in order to perform first an axial displacement of the firing pin followed by another rotating and axial displacement of the same firing pin.
6. A device according to claim 5, characterised in that it comprises a modulus of neutralisation (20) of the firing pin (7) located between the latter and the downstream part (4) of the pyrotechnic chain.
7. A device according to claim 6, characterised in that the cylindrical neutralisation modulus (20) can have three series of lights (20a, 20b, 20c) of different lengths distributed over the periphery of the modulus, for housing at least one lug (7e) of the firing pin (7).
8. A device according to claim 7, characterised in that the firing pin can comprise three external lugs (7e) distributed over 120° on its periphery and located facing one of the three series of lights also distributed over the modulus in order to perform, either a neutralisation of the storage and transport of the firing pin in a safe position, or a functional neutralisation in an armed position of the latter, or the firing of the downstream section (4) of the chain.
9. A device according to claim 8, characterised in that it comprises a self-destruction modulus comprising a composition that generates gas (5a, 5b) contained in piston (5) and initiated by the upstream section of the chain, an exhaust vent (5c) made in the piston and located, after the piston displacement, opposite an axial volute (7d) attached to the firing pin, to result in a rotational and axial displacement of the latter followed by the firing of the downstream section (4) of the chain.
10. A device according to claim 9, characterised in that the gas generating composition contained in piston (5) can comprise a delay composition (5a) associated with a reinforcing composition (5b).
11. A device according to any of the previous claims comprising an axial element for interrupting the pyrotechnic chain located in the downstream section of the chain housed in a cylindrical sheath (26), and rotated by mechanical means characterised in that the driving mechanical means are actuated by the sole rotation of the firing tap head, thus allowing a chain manual alignment and disalignment.
12. A device according to claim 11, characterised in that the interrupting element comprises a cylinder (27) having an axial orifice, attached to an in-line barrel (28) rotated by the mechanical means from a radial position to an axial position of the cylinder and vice-versa.
13. A device according to claim 12, characterised in that the mechanical means which rotates the barrel (28) can comprise an internal cylindrical part (25) mobile in rotation, partly housed in sheath (26) and connected to the barrel by its lower end (25a), its upper end being driven by the rotation of the body (24 ) and tap head (23).
14. A device according to claim 13, characterised in that the barrel is fitted out with a tenon (30) set in a helicoidal groove (31) done in cylindrical sheath (26), ensuring a 90° rotation of the cylinder (27).
15. A device according to claim 13, characterised in that the barrel (28) comprises teeth (32) set in a sheath rack (33) to ensure a 90° rotation of the cylinder.
16. A device according to any of the previous claims, characterised in that the downstream section (4) of the pyrotechnic chain successively comprises a percussion fuse (4a) a (4b) made of lead azide, a priming relay (4c) made of cyclonite, the cylinder interrupting element (27), then a principal relay (4d) made of cyclonite.
17. A device according to claim 16, characterised in that interrupting cylinder (27) also contains an intermediate relay load in secondary explosive of the cyclonite type.
18. An application of the firing device of a pyrotechnic load according to any of the previous claims, applied to a three-function firing tap allowing a fuzing, percussive or percussive-fuzing operation of the load, of the type comprising a selector of the operating modes, an impact detecting modulus and a delay modulus, characterised in that the selector is constituted by the external cylindrical wall (23) of the tap head, mobile in rotation around the cylindrical body (24) of the tap drilled by the central bore (2).
19. A firing tap according to claim 18, characterised in that this delay modulus solid with selector (23) comprises a mechanical oscillator (19) regulating the rotation of at least one toothed wheel (18) geared in at least one axial rack (7c) attached onto the external wall of firing pin (7), to produce a priming delay in percussive-fuzing mode.
20. A firing tap according to claim 19, characterised in that the external wall of firing pin (7) comprises four parallel racks (7c, 7c2, 7c3, 7c4) having different lengths, each corresponding to priming delays of one second, seven tenths, four tenths and one tenth of a second.
21. A firing tap according to claim 20, characterised in that the multidirectional impact detecting modulus with adjustable sensitivity used in percussive mode and percussive-fuzing mode, housed in an axial bore (37) of the cylindrical body (24) of the tap, comprises a master-cylinder (10) associated with a first spring (11), a counter-cylinder (12) associated with a second spring (13), a transverse detecting ball (14) interposed between the master-cylinder and the counter-cylinder, two locking and unlocking balls (15) and (16) of the modulus controlled by the axial displacement of firing pin (7) and another functional locking and unlocking ball (17) of the modulus forbidding or allowing its operation by means of selector (23).
22. A firing tap according to claim 21, characterised in that the transverse detection ball (14) of the impact detecting modulus is made of a dense tungsten type material.
23. A firing tap according to claim 22 , comprising a ring (34a) connected to a pin (34) which locks a catch (22) and an upstream firing pin (29) controlling firing of the chain upstream part (3), characterised in that it comprises means which forbid the extraction of a pin (34) when selector (23) is in safe position.
24. A firing tap according to claim 23, characterised in that the means forbidding the extraction of pin (34), when the selector is in safe position, comprise a circular groove (26e) of sheath (26) and an elastic lock (23e) of the selector, enclosing a part of ring (34a).
25. A firing tap according to claim 24, characterised in that the rotational selector (23) has a safe initial position and, by successive rotations of 90°, assumes at least three different positions, each corresponding to one of the modes of operation :

    in safe position, pin (34) is locked, the pyrotechnic train is interrupted by element (27) maintained in a radial position, firing pin (7) the three pins (7e) of which are opposite the three short safety lights (20a), is locked by the ball (8) set in the internal circular groove (7f) of the firing pin, and the toothed wheel (18) of the delay modulus is located apart from the firing pin racks (7c), and the impact detecting modulus is locked by both balls (15) and (16 ) respectively blocking master-cylinder (10) and counter-cylinder (12) actuated by firing pin (7) in the initial position ; in addition, the functional locking ball (17) maintained by selector (23) also blocks master-cylinder (10),

    a first 90° rotation of the selector, corresponding to the load fuzing operation, successively provoking the unlocking of pin (34) thus allowing its extraction, the alignment of the pyrotechnic train by rotating the interrupting element (27) 90° and rotating firing pin (7) in relation to the modulus of neutralisation (20) by bringing the three lugs (7e) of the firing pin opposite the three longer lights (20b) of the modulus corresponding to the position of the functional neutralisation of the firing pin, the delay modulus and impact detector remaining inactive,

    a second 90° rotation of the selector, corresponding to the percussive operation, moreover provoking the release of the functional locking ball (17) of the impact detector modulus, the latter being then housed in an internal circular groove (23b) of the selector to activate this modulus,

    a third rotation of 90° of the selector, corresponding to the percussive-fuzing operation, moreover provoking the alignment of toothed wheel (18), of the delay modulus with the first rack (7c) of the firing pin corresponding to a percussion delay of one second, the impact detection modulus remaining active.
26. A firing tap according to claim 25, characterised in that selector (23) is in the percussive-fuzing position, three successive additional rotations in the same direction of the selector provoking the alignment of toothed wheel (18) of the delay modulus with, respectively, the second rack (7c2) of the firing pin corresponding to a percussion delay of seven tenths, the third rack (7c3) of the firing pin corresponding to a percussion delay of four tenths and the fourth rack (7c4) of the firing pin corresponding to the percussion delay of one tenth of a second.
27. A firing tap according to any of claims 21 to 26, characterised in that in percussive and percussive-fuzing position of selector (23) and the impact detection modulus being inactive, the self-destruction modulus (5a, 5b, 5c, 7d) associated with control means (5, 6) of the firing pin provoke the firing of the downstream section (4) of the chain followed by the explosion of the device.

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