EP0554149A1 - Fuse - Google Patents

Abstract

Delay fuse for a pyrotechnic missile, especially a manually or mechanically launched grenade, comprising a body (4) equipped with a control mechanism comprising a release lever (1) and a percussion mechanism (28) cooperating with a primary pyrotechnic module provided with a primer (3), with a delay composition (9) and with a primary explosive (13) which are capable of ensuring the initiation of the charge of the associated missile, the said primary pyrotechnic module being designed in such a way that the primary explosive (13) cannot be initiated without passing by way of the delay composition, the primary pyrotechnic module (5) being axially displaceable in the said body towards the main charge, means (2) for keeping the primary pyrotechnic module (5) axially apart from the main charge (19), and a screen (12a, 15) interposed between the main charge and the end part of the primary pyrotechnic module containing the primary explosive (13), characterised in that the means (2) for keeping the primary pyrotechnic module (5) axially apart from the main charge (19) are purely mechanical means actuated by the release lever (1), and in that the screen interposed between the main charge and the end part of the primary pyrotechnic module (5) comprises a capsule (15) for closing a cup (18) containing the main charge (19), and a pellet (12a) which is carried by the end of the primary pyrotechnic module (5) containing the primary explosive (13) and which is engaged in the capsule (15), the pellet (12a) and the capsule (15) being shaped so as to be fixed to one another in the event of the excitation of the primary explosive (13) in the storage position and to create a physical barrier to the shock wave or to the splinters. <IMAGE>

Description

The subject of the present invention is an improvement to the delay igniter plugs for pyrotechnic devices, these devices being able in particular to be grenades usable by hand or with mechanical launching means, and having explosive, smoke-producing, lighting or combined functions.

French patent n ° 76 00 800 describes an igniter plug provided with a trigger lever provided with a locking pin and associated with a percussion mechanism of a waterproof pyrotechnic module. This comprises a primer, a delay composition, a primary explosive and a main priming charge capable of ensuring the initiation of the charge of the associated device, this module being secured in leaktight manner with the body of the plug.

This plug has the advantage of guaranteeing a sufficient seal between the ignition system and the other constituent elements of the pyrotechnic chain of the module, so that the primary explosive cannot be initiated otherwise than through the composition. delay.

The first addition No. 76 17 248 to the aforementioned patent describes means for guiding the trigger lever in rotation over a determined angular sector, after unlocking this lever, so as to allow an almost instantaneous escape of the lever in question as soon as it has exceeded the angular guide sector. According to a preferred embodiment, the cap body is thus provided with two lateral ramps arranged under the trigger lever, so as to guide the latter in rotation after unlocking, by cooperation of the ramps with two corresponding lateral cheeks of the lever.

In these two known embodiments, the pyrotechnic module, which is mounted in a fixed position relative to the body of the plug, constitutes a complete pyrotechnic chain, capable of operating in the event of accidental excitation of the primer, apart from the normal mechanical triggering by the lever and its associated percussion mechanism, this normal triggering comprising, in order, the uncoupling, lever escapement and percussion of the primer.

It has thus been observed that hand grenades can explode accidentally in the event of a fall onto very hard ground, prolonged storage in premises at abnormally high temperature, exposure to electromagnetic fields causing either induced currents or the formation of charges. electrostatic can condition either by direct action or by discharge, untimely start-up operation.

In order to improve the safety of storage and use of these pyrotechnic devices, in particular by eliminating any risk of accidental triggering of the main priming charge and consequently of the charge of the corresponding device, the French patent n ° 78 17 119 described an igniter plug in which the pyrotechnic module is separated from the main priming charge, and the igniter cap is provided with a safety device capable of preventing the triggering of the main priming charge in the case where the excitation of the primer has an origin other than the normal mechanism of percussion of the plug.

The present invention relates more precisely to the igniter plugs of the latter type. It aims to provide new means to constitute the interruption screen between the pyrotechnic module and the final charge in order to further strengthen the safety of storage and use of the igniter plug.

It therefore relates to a delay igniter plug for pyrotechnic device, in particular a grenade manual or mechanical launching, comprising a body provided with a control mechanism comprising a trigger lever and a percussion mechanism cooperating with a primary pyrotechnic module provided with a primer, a retarding composition, a primary explosive capable of initiate the charge of the associated device and arranged so that the primary explosive cannot be initiated without passing through the retarding composition, the primary pyrotechnic module being axially movable in said body towards the main charge , means for holding the primary pyrotechnic module axially separated from the main charge and a screen interposed between the main charge and the terminal part of the primary pyrotechnic module containing the primary explosive, characterized in that the means for holding the primary pyrotechnic module separated axially of the main load are exclusively mechanical means, actuated by the trigger lever and in that the screen interposed between the main charge and the terminal part of the primary pyrotechnic module, comprises a capsule for closing a bucket containing the main charge and a tablet carried by the end of the pyrotechnic module primary containing the primary explosive and engaged in the capsule, the tablet and the capsule being shaped to be secured to one another in the event of excitation of the primary explosive in the storage position and create a physical barrier to the shock wave or bursts.

In this way, in the igniter plug according to the invention, the screen effect is obtained in the storage position by the axial spacing between these two primary and secondary pyrotechnic modules, the axial sliding of the two modules being prevented by the means holding. In the event of a storage incident, i.e. firing the primer without unlocking the lever triggering, the initiation of the primary explosive housed at the base of the primary pyrotechnic module will cause the pellet to be crimped into the capsule with which it then forms a solid screen preventing the initiation of the pyrotechnic charge of the secondary module.

Thus, the security of use and storage of the invention is total.

• la Fig.1 est une vue en coupe et élévation longitudinale d'un mode d'exécution du bouchon allumeur conforme à l'invention;
• la Fig.1a est une vue partielle en coupe d'un autre mode de réalisation de l'écran de séparation du module pyrotechnique primaire et de la charge principale du bouchon allumeur en position de repos;
• la Fig.1b est une vue analogue à celle de la Fig.la, montrant l'écran après détonation du module pyrotechnique primaire;
• la Fig.2 est une vue en plan de dessus du bouchon allumeur de la Fig.1, dont la goupille est pourvue d'un anneau de sécurité;
• la Fig.3 est une vue en élévation du bouchon des Fig.1 et 2;
• la Fig.4 est une vue en élévation du bouchon allumeur suivant la direction de la flèche F de la Fig.3;
• la Fig.5 est une vue partielle extérieure d'un autre mode de réalisation du bouchon allumeur suivant l'invention;
• la Fig.6 est une vue partielle en coupe suivant la ligne 6-6 de la Fig.5.

The invention will be better understood with the aid of the description which follows, given solely by way of example and made with reference to the appended drawings, in which:

• Fig.1 is a sectional view in longitudinal elevation of an embodiment of the igniter plug according to the invention;
• Fig.1a is a partial sectional view of another embodiment of the separation screen of the primary pyrotechnic module and the main charge of the igniter plug in the rest position;
• Fig.1b is a view similar to that of Fig.la, showing the screen after detonation of the primary pyrotechnic module;
• Fig.2 is a top plan view of the igniter plug of Fig.1, the pin of which is provided with a safety ring;
• Fig.3 is an elevational view of the cap of Fig.1 and 2;
• Fig.4 is an elevational view of the igniter plug in the direction of arrow F in Fig.3;
• Fig.5 is a partial exterior view of another embodiment of the igniter plug according to the invention;
• Fig.6 is a partial sectional view along line 6-6 of Fig.5.

In its embodiment shown in Figures 1 to 4, the delay igniter plug for vehicles Pyrotechnics, such as hand grenades, has a body 4 made of plastic loaded with glass fiber, but which could alternatively be made of light alloy or any other equivalent material.

On this body 4 are adapted a primary pyrotechnic module 5 and a secondary pyrotechnic module 17 which will be described in more detail below.

The body 4 is provided with a control mechanism of known type which comprises a trigger lever 1 provided with a transverse locking pin 25 equipped with a gripping ring 26.

The control mechanism also comprises an elastic striker device 28 constituted by a spring 22 wound around a transverse axis 21 cooperating with a yoke 23 which carries the striker 24. This striker device can rotate around the axis 21, which is held by the side cheeks 1b of the lever 1.

The lever 1 is itself engaged by its front spout 1c in the front face of the body 4. The body 4 also comprises two curved lateral ramps 4b arranged under the lever 1 so as to guide the latter in rotation after unlocking the pin 25 .

The primary pyrotechnic module 5 with delay is constituted by a metal case 10, for example of light alloy, at the base of which is crimped a cup 12 whose length and diameter correspond to those of an axial chamber 29 formed in the pyrotechnic module secondary 17, as will be described in more detail below.

The metal case 10 contains at its upper end a percussive primer 3, held by crimping and protected by a varnish or a resin. Under the primer 3, a retarding composition 9 is housed in the case 10.

The cup 12 set in the case 10 contains an initiation composition 11 and a micro-detonator 13 which constitutes the primary explosive of the pyrotechnic chain.

The base of the bucket 12 is integral with a metal pellet 12a made of material.

The case 10 is held in a fixed position relative to the body 4 by a jumper 2 introduced with gentle friction in two openings passing through the body 4 and the case 10.

As seen in Figures 1 and 2, the jumper 2 has a vertical part 2a forming a loop directed upwards and two horizontal tabs intended to cooperate with the aforementioned lights. The jumper is held in place by the lever 1. Said lever 1 has on its upper face a re-entrant finger intended to drive the jumper 2 during the ejection of the lever 1 after unlocking of the pin 25.

The case 10 of the primary pyrotechnic module 5 is partially inserted into the case 16 of the secondary pyrotechnic module 17 with, however, an axial spacing allowing it to slide inside said case after release of the jumper 2.

A seal 6 is interposed between the case 10 of the primary pyrotechnic module 5 and the case 16 of the secondary pyrotechnic module 17, while a seal 7 is interposed between the latter and the body 4.

The secondary pyrotechnic module 17 contains a detonation relay 27 constituted by an aluminum cup 18 containing a secondary explosive 19 and a closure capsule 15 which, in combination with the tablet 12a placed at the base of the cup 12 of the primary module 5, forms a screen between the micro-detonator 13 and the secondary explosive 19 which constitutes the main priming charge. The capsule 15 has a chamfer 15a intended to receive portions of the wall of the cup 12 adjacent to the pellet 12a under the effect of an accidental detonation of the primary explosive 13.

In Fig.1 we see that the cup 18 has an axial chamber 29 whose shape agrees with that of the cup 12 of the primary module 5 and that the capsule 15 has an axial opening in which in the storage position is housed the pellet 12a of the primary module 5.

According to the variant shown in FIG. 1a, the wall of the cup 12b is open at its end and an attached patch 12c forming a safety pad is engaged and crimped at the end of the cup 12b. This patch includes a portion 12d with thin walls.

The end of the cup 12b carrying the pellet 12c is slidably inserted into the capsule 15 in the form of a ring of the secondary module 17. The capsule 15 has a chamfer 15a at its upper internal part.

The behavior of this arrangement will be described with reference to Fig.1b.

The materials of the patch 12c and of the capsule 15 are chosen to be strong enough to stop the shock wave that can be generated by the primary explosive 13, and prevent it from reaching the secondary explosive 19, and sufficiently ductile to conform together and form a barrier during the initiation of the primary module 5 in the storage position of the igniter plug.

The secondary module 17 is closed at its base by a stop and sealing resin 20.

The case 16 of the secondary module 17 has at its upper end a collar whose lateral surfaces cooperate with the internal wall of the body 4.

The base of the body 4 is connected to a trunk 14, the upper lips of which clip into a groove made on the outer wall of the case 16. This trunk 14 has the function of limiting the mechanical effects of the micro-detonator 13 if it were to operate in the storage position.

A seal 8 placed on the body 4 coaxially with the modules 5 and 17 ensures a sealed connection with the device on which the igniter plug is mounted.

The igniter plug according to the invention, being mounted on a device such as an explosive grenade for example, its operation is as follows:

The grenade is pinned by extracting by rotation (mark R in FIG. 3) and combined traction the pin 25 by means of the ring 26 then it is launched. The trigger lever 1 is no longer held in its locking position, the elastic stress of the spring 22 by means of the striker 24 makes it pivot. After a rotation of approximately 30 ° the finger 1a of the trigger lever 1 comes to bear on the jumper 2 and begins its extraction. In the following phase of the rotation of the lever, the striker 24 escapes and strikes the primer 3, the jumper 2 not having yet released the primary pyrotechnic module with delay 5. By inertia, the trigger lever 1 ends its rotation and is freed from the body 4 by driving the jumper 2, which has the effect of unlocking the primary pyrotechnic module with delay, and since the latter is always subjected to the thrust of the striker 24 in association with the spring 22, there is transfer of the primary pyrotechnic module with delay 5 and consequently clearing of the screen.

The solid element or pellet 12a of the cup 12 coming from the bottom of the cell 29 of the cup 18, the micro-detonator 13 is then in the position of initiation of detonation by radial effect.

The percussion of the primer 3 had the effect of initiating the delayed composition 9. At the time determined by the delay column 9 there is excitation of the load 11 and by thermal effect initiation of the micro-detonator 13. The micro-detonator 13 will by radial effect cause the detonation of the relay 27.

If for any reason the micro-detonator were to be excited in the storage position, the element 12a is crimped onto the crown of the capsule 15 due to rupture and deformation in the vicinity of the capsule 12a of the wall of the well 12 under the action of the detonation of the primary explosive 13, to form a disc. The radial effects are also blocked by the trunk 14.

In the case of the embodiment shown in FIGS. 1a and 1b, the detonation of the primary explosive 13 generates a shock wave whose propagation in the safety capsule 12c causes the radial deformation of the thin-walled portion 12d due to the phenomenon known as plate separation.

Under the effect of the shock wave, the thin walls 12d, when deformed, adapt to the chamfer 15a of the capsule 15 and ensure that the pellet 12c is joined to the capsule 15, thereby achieving a physical rupture of the pyrotechnic chain of the igniter plug in the event of abnormal operation of the primary module 5.

• que les dispersions admissibles sur les diamètres intérieur de la capsule ou bague 15 et extérieur de la pastille ou plot de sécurité 12a ou 12c soient suffisantes,
• que le dimensionnement du chanfrein 15a de la capsule soit compatible avec la hauteur des lèvres déformables ou parois minces 12d de la pastille 12c dans le cas du mode de réalisation des figures 1a, 1b ou avec la hauteur des portions de la paroi du godet 12 résultant de la rupture de celle-ci dans le as du mode de réalisation de la figure 1.

Such an operation implies:

• that the admissible dispersions on the inside diameters of the capsule or ring 15 and outside of the security patch or pad 12a or 12c are sufficient,
• that the dimensioning of the chamfer 15a of the capsule is compatible with the height of the deformable lips or thin walls 12d of the patch 12c in the case of the embodiment of FIGS. 1a, 1b or with the height of the portions of the wall of the resulting cup 12 of breaking thereof in the ace of the embodiment of FIG. 1.

On Fig.5 and 6, there is shown another embodiment of the igniter plug according to the invention.

This igniter plug differs from the igniter plug described with reference to FIG. 1 essentially in two points.

It comprises a jumper 30 for holding the primary pyrotechnic module 5 axially spaced from the main charge, this jumper comprising a vertical part 30a in the form of a loop directed downwards and horizontal legs 30b similar to those of jumper 2 of the embodiment of FIG. 1 engaged in the body 4 of the plug and in the case 10 of the primary pyrotechnic module 5.

In this embodiment, the case 10 of the primary module 5 is slidably mounted in the case 16 of the secondary module 17 with the interposition of a bellows seal 31.

The actuating lever 1, the construction of which is similar to that of the lever 1 of the embodiment of FIG. 1, differs from the latter in that, instead of a rider extraction finger, it comprises a member for extraction formed by a notch 32 formed in the part of the lever 1 adjacent to the loop, said notch having folded tabs 32a engaged behind the loop 30a of the jumper 30 in the rest position and ensuring the extraction of the jumper 30 during the release of the release lever 1 relative to the body 4.

For the rest, the construction and operation of this embodiment of the igniter plug are the same as those of the plug of FIG. 1.

Thus, the improvements provided by the present invention considerably improve safety for storing and using the igniter plug and the device on which it is mounted.

The invention is not limited to the embodiment described and may include alternative embodiments.

Claims (10)

Delayed igniter plug for pyrotechnic device, in particular grenade with manual or mechanical launching, comprising a body (4) provided with a control mechanism comprising a trigger lever (1) and a percussion mechanism (28) cooperating with a pyrotechnic module primary provided with a primer (3), a retarding composition (9), a primary explosive (13) capable of ensuring the initiation of the charge of the associated device and arranged so that the primary explosive (13) cannot be initiated without passing through the retarding composition, the primary pyrotechnic module (5) being movable axially in said body towards the main charge, means (2) for holding the primary pyrotechnic module (5) axially separated from the main charge (19) and a screen (12a, 15; 12c, 15) interposed between the main charge and the terminal part of the primary pyrotechnic module containing the primary explosive (13), characterized in that the hubs ns (2) for holding the primary pyrotechnic module (5) axially separated from the main charge (19) are exclusively mechanical means, actuated by the trigger lever (1) and in that the screen interposed between the main charge and the terminal part of the primary pyrotechnic module (5), comprises a capsule (15) for closing a bucket (18) containing the main charge (19) and a pellet (12a; 12c) carried by the end of the primary pyrotechnic module (5) containing the primary explosive (13) and engaged in the capsule (15), the pellet (12a; 12c) and the capsule (15) being shaped to be secured to one another in the event of excitation primary explosive (13) in the storage position and create a physical barrier to the shock wave or splinters. Igniter plug according to claim 1, characterized in that the tablet (12a) has come from material with a cup (12) containing the primary explosive (13) and the connection of the pellet (12a) with the capsule (15) is ensured by crimping due to rupture and deformation in the vicinity of the capsule (12a ), of the wall (12) of the primary pyrotechnic module under the action of the detonation of the primary explosive (13) which it contains, and adaptation of the wall on a chamfer (15a) of the capsule (15). Igniter plug according to claim 1, characterized in that the pellet (12c) is an insert provided with a thin-walled portion (12d), engaged in the end of a cup (12b) containing the primary explosive ( 13) and in that the connection of the patch (12c) with the capsule (15) is ensured by crimping by radial deformation of the thin-walled portion (12d) due to the phenomenon of detachment of the plates under the effect of the shock wave generated by the detonation of the primary explosive (13) and adaptation of the thin walls on a chamfer (15a) of the capsule (15). Igniter plug according to one of claims 1 to 3, characterized in that the means for holding the primary pyrotechnic module (5) spaced axially from the main charge (19), comprise a jumper (2; 30) housed in the body ( 4) of the plug and in engagement with the primary pyrotechnic module (5), said trigger lever (1) comprising a member (1a; 32a) for extracting the jumper, when the trigger lever (1) is released relative to to the body of said plug. Igniter plug according to claim 4, characterized in that the jumper (2) has a vertical part (2a) forming a loop and two horizontal tabs intended to cooperate with transverse lights made in the upper part of the body (4) and of the primary module (5). Igniter plug according to claim 5, characterized in that the jumper (2) has a vertical part (2a) forming an upwardly directed loop and the member for removing the jumper (2) is a finger (1a) carried by the lever and cooperating with the vertical part (2a) to extract the rider from the body when the release lever (1) is released. Igniter plug according to claim 5, characterized in that the jumper (30) has a vertical part (30a) forming a loop directed downwards and the rider removal member (30) is formed of folded tabs (32a) d '' a notch (32) formed in a part of the trigger lever (1) adjacent to the loop (30a), the tabs (32a) being engaged behind the mouth (30a) and cooperating with it by traction to extract the rider outside the body when the release lever (1) is released relative to the body (4). Igniter plug according to one of Claims 1 to 7, characterized in that the main charge (19) is contained in a secondary pyrotechnic module (17) comprising a case (16) inside which the primary pyrotechnic module (5) is partially inserted by sliding. Igniter plug according to one of the preceding claims, characterized in that it comprises at the base of its body (4) an added boot (14) surrounding the primary explosive (13) in the locked position of the plug. Igniter plug according to one of claims 1 to 6, characterized in that the percussion mechanism (28) constitutes a means of displacement in translation of the primary pyrotechnic module (5) in the body (4).

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