EP1672308B1 - Dispositif d'allumage pour une charge explosive ou une composition pyrotechnique - Google Patents

Abstract

The initiation system (5), comprising at least two initiators (9) connected to a power source, has the initiators mounted on a single insulating support (8) together with conductors that connect them to the power source. The initiators have at least one semiconductor bridge and consist of at least one first group distributed round a peripheral crown, and at least one second group forming diametrical arms, with each of them having one terminal connected to a common conductor.

Description

The technical field of the invention is that of devices for initiating an explosive charge or a pyrotechnic composition.

Known devices are used in particular to initiate the explosive charges of military heads generating splinters or formed charge (generating a jet or a core). Similarly, in flash charges, it is sometimes necessary to initiate an angular sector to orient the spray. This angular sector being dependent on the desired focus.

Generally, the initiation devices use at least one initiating component such as a detonator or an igniter. These components are well known to those skilled in the art. Depending on the technology used they include for example a hot wire, a resistive bridge or a semiconductor bridge (known under the name: SCB or "semi conductor bridge") which, when traversed by an electric current, communicates with the energy to an inflammatory or detonating pyrotechnic composition.

Today, we seek in the field of military heads to propose multi-mode heads that is to say that depending on operational requirements generate splinters, a hollow charge jet or a core formed by explosion.

The US Patent 5939663 thus describes a multi-function head whose initiation device comprises an axial detonator and a ring of peripheral detonators. All the detonators are connected to initiation means by separate wire connections. Depending on the detonators that are ordered, we obtain a coherent stream or a projection of splinters.

The initiation device thus defined is complex and expensive to implement since it requires the mounting of the various detonators on a support which must be positioned precisely with respect to the load so that the desired effect is ensured.

It is also bulky axially and requires the realization of a wired connection also bulky.

The DE-40011243 , which forms a starting point for the preamble of claim 1, describes an initiation device for an explosive charge, this device comprises a selection circuit, two initiation means carried by a single insulating support and connected to a source energy.

This patent does not disclose the structure of the initiation means nor the nature of the means providing the electrical connection between the initiation means and the selection circuit.

It is the object of the invention to provide an initiation device for overcoming such disadvantages.

Thus, the initiation device according to the invention is compact and inexpensive to manufacture. It is adaptable to different types of explosive charges and can reliably ensure the initiation of an explosive charge according to several modes of operation.

The field of application of the invention is not limited to explosive multi-mode military heads. The device according to the invention can in fact also be used to initiate a pyrotechnic composition, for example a gas generating composition having several operating regimes (for example a gas generator comprising several selectively initiatable gas cartridges).

Thus, the subject of the invention is an initiation device for an explosive charge or a pyrotechnic composition, which device comprises at least two initiation means carried by a single insulating support and connected to a power source, a device characterized in that that the single insulating support also carries the conductors connecting the initiation means to the energy source, the initiation means comprising pads carried by the surface of the support and connected by a semiconductor or resistive bridge, the conductors being made in the form of conductive tracks carried by a face of the support, the support comprising at least a first group of initiation means distributed over a peripheral ring and at least a second group of initiation means distributed over at least one diametric arm, all the initiator means comprising a first stud connected to a common conductor and the support also comprising at least two other control conductors which are each connected to second pads of two groups of separate initiation means.

According to a particular embodiment, the initiation means comprise at least one semiconductor bridge.

The initiation device according to the invention may comprise initiation means distributed over a peripheral ring and on two orthogonal diametral arms.

According to another particular embodiment, the device comprises at least a first control conductor ensuring the initiation of an axial initiation means.

According to another particular embodiment, the device comprises at least one second control conductor ensuring the initiation of a first ring of initiation means distributed on the arms around the axial initiation means.

According to another particular embodiment, the device comprises at least a third control conductor ensuring the initiation of a sector of means for initiating the peripheral ring.

According to another particular embodiment, the peripheral ring comprises four sectors of initiation means each of which can be initiated separately by specific control conductors.

• la figure 1 montre en coupe longitudinale une tête militaire multi-modes mettant en oeuvre un dispositif d'initiation selon l'invention,
• la figure 2 est une vue en coupe longitudinale d'un mode de réalisation du dispositif d'initiation seul,
• la figure 3a est une vue schématique d'un pont semi-conducteur élémentaire mis en oeuvre dans un mode de réalisation du dispositif d'initiation selon l'invention,
• la figure 3b est une vue schématique d'un pont résistif élémentaire mis en oeuvre dans un autre mode de réalisation du dispositif d'initiation selon l'invention,
• la figure 3c est une vue en coupe transversale partielle du support au niveau d'un moyen d'initiation,
• la figure 4 est une vue de dessus du support portant les différents moyens d'initiation élémentaires,
• les figures 5a, 5b, 5c et 5d sont des vues analogues à la figure 4 mais schématisant les alimentations électriques utilisées pour assurer respectivement un fonctionnement : à amorçage central, à amorçage annulaire, à amorçage radial ou à amorçage par secteur.

The invention will be better understood on reading the following description of various embodiments, a description given with reference to the appended drawings and in which:

• the figure 1 shows in longitudinal section a multi-mode military head implementing an initiation device according to the invention,
• the figure 2 is a longitudinal sectional view of an embodiment of the initiation device alone,
• the figure 3a is a schematic view of an elementary semiconductor bridge implemented in one embodiment of the initiation device according to the invention,
• the figure 3b is a schematic view of an elementary resistive bridge implemented in another embodiment of the initiation device according to the invention,
• the figure 3c is a partial cross-sectional view of the support at an initiation means,
• the figure 4 is a view from above of the support carrying the various elementary initiation means,
• the Figures 5a, 5b , 5c and 5d are similar views to the figure 4 but schematizing the power supplies used to respectively provide operation: centrally primed, ring primed, radial ignition or sector priming.

Referring to the figure 1 , a formed charge warhead 1 comprises an explosive charge 2 disposed in a cylindrical envelope 3. A concave coating 4 is applied against the explosive charge 2.

The detonation characteristics of the explosive and the geometry of the coating 4 are chosen so that this warhead can have several different modes of operation depending on the initiation mode chosen. These characteristics are well known to those skilled in the art and will not be described here because they are not the subject of the present invention. For example, see EP1164348 which describes such a multi-function military head.

The military head 1 can be initiated by an initiation device 5. The latter comprises a cylindrical housing 6 having substantially the same external diameter as the casing 3 of the military head 1 and closed by a bottom 6a plane on which is arranged a axial opening 7.

According to the invention the housing 6 encloses a single insulating support 8 which carries initiation means 9. A connector 10 is fixed at a rear face of the support 8 and it allows the connection of the initiation device 5 to an electronic control means 11 which incorporates a power source enabling activation of the initiation device 5. The connector 10 leaves the housing through the opening 7.

The housing 6 also contains a detonating pyrotechnic composition 12, for example hexanitrostilbene (HNS) or compressed hexogen (RDX), which is applied by compression against the support 8. One could also use for the composition 12 a sheet plastic explosive, for example an explosive based on rubber and pentrite (explosive known under the trademark Formex).

The housing 6 is fixed to the casing 3 by connecting means not shown here, for example by an outer ring screwed or crimped both on the casing 6 and on the casing 3 so that the military head 1 and the device Initiation 5 may for example form only one compound.

Moreover, as is more particularly visible in the figure 2 a thin flap 13, for example made of aluminum, is applied to the face of the detonating composition 12 intended to come into contact with the explosive charge 2. This flap will perform a sealing function during storage of the initiation device 5 regardless of a military head 1.

The support 8 is visible more precisely at the figure 4 . It is made of an insulating material and carries initiation means 9 on one of its surfaces intended to come into contact with the detonating composition 12.

The Figures 3a and 3b show in an enlarged manner two different embodiments of such an initiation means 9. figure 3a Thus shows an initiation means 9 comprising a bridge 15 of semiconductor material which is disposed between two pads 14 of conductive material. The semiconductor bridge for example, made of doped silicon and copper pads.

The pads have a width opposite the bridge which is less than their width away from the bridge. Such an arrangement makes it easier to initiate the initiation plasma between the pads.

Such a semiconductor bridge is well known to those skilled in the art. For example, we can refer to EP0711400 which describes a semiconductor bridge initiator.

When a voltage of a certain level (which depends on the dimensional and physical characteristics of the material used to make the bridge 15) is applied between the pads 14, a plasma is generated through the bridge 15 and the resulting energy ensures the initiation of the detonating composition in contact with the bridge.

The figure 3b shows another embodiment of an initiation means 9. In this mode the pads 14 are connected by a resistive conductive element 16 (for example gold). In this embodiment (also well known to those skilled in the art) it is the heating by Joule effect of the resistive element 16 (or explosion) that ensures the initiation of the detonating composition.

According to a preferred embodiment, the various initiation means 9 will be applied to the support 8 according to the integrated circuit manufacturing technology.

It is indeed conventional to carry out according to this technique a plurality of initiation means (semiconductor bridge or resistive) on the same support, the means then being cut for example by laser to be individually integrated each into a housing separate.

In accordance with the invention, a support carrying all the initiation means (with a particular geometrical distribution which will be specified later) and conductors (or tracks) will be realized according to this technique. conductive) which ensure (via the connector 10) the connection of the initiation means 9 to a power source incorporated in the control means 11.

The support 8 may thus be constituted by an amorphous silicon disk on which the initiation means and the conductive tracks will be made by metallization and / or vacuum deposition.

We see on the figure 4 that the support 8 carries an axial initiation means 9a and a first group 17 of initiator means 9 distributed on a peripheral ring 18 (there are here twenty four initiators 9 regularly angularly distributed on the peripheral ring 18).

The support 8 also comprises a second group of initiator means 9 distributed over at least one diametral arm.

There are here two diametral arms 19a and 19b each comprising six initiating means 9. It will be noted that the ends of the diametral arms pass through initiating means 9b, 9c, 9d and 9e which belong to the peripheral ring 18.

As is visible on the figure 4 an upper surface of the support carries conductive tracks making it possible to connect the poles of certain initiators to the connector 10.

Thus all the initiating means comprise a first stud 14a which is connected to a common conductor C (all the pins connected to the common conductor are shown hatched on the figure 4 ). This common circuit passes through the pad 14a of the initiating means 9c and comprises a peripheral circular conductive track 20a and two other internal circular tracks 20b and 20c coaxial with the first. The common circuit also comprises a track 21 connecting the different circular tracks 20a, 20b and 20c of the common circuit.

Furthermore, the upper face of the support 8 carries other conductive tracks making it possible to connect together. the second pads 14b of a number of different initiating means 9.

There are thus several groups of initiators 9 which are interconnected and which can therefore be initiated simultaneously by means of specific control drivers.

There is thus a first control conductor S1 ensuring the initiation of an axial initiator means 9a.

There is also a second control line _S2 which ensures the initiation of a first ring 22 of four initiating means distributed on the arms 19a and 19b and around the axial initiator means 9a. The poles 14b of these initiators are all connected to each other by a circular portion of track 25.

In a similar way there are control conductors S2 _b and S2 _c which ensure the initiation of two other rings 23 and 24 of four initiating means distributed on the arms 19a and 19b and around the axial initiator means 9a. The poles 14b of these initiators are also all connected to each other by a portion of circular track, respectively 26 and 27.

Finally, there is at least one third control conductor S3 _a which initiates a sector 28 of initiating means 9 all located on the peripheral ring 18.

The device represented in figure 4 thus comprises on its peripheral ring 18 four sectors 28, 29, 30 and 31 which are delimited by the arms 19a and 19b. Each sector comprises five contiguous initiating means.

Each of these sectors is controlled by a specific control conductor (S3 respectively _a, S3 _b, S3 _c and S3 _d). At each sector, the pads 14b of the initiators are all connected to each other by a portion of circular track. These track portions are in the figure the marks 32, 33, 34 and 35.

Finally, as already mentioned above, there is on the peripheral ring 18 four insulated initiators 9b, 9c, 9d and 9e arranged at the ends of the arms 19a and 19b. Each of these initiators is controlled by a specific control conductor Si _b , Si _c , Si _d and Si _e .

All the control conductors are connected to the connector 10 which thus comprises at least 13 pins.

These connections are schematically represented on the figure 4 by broken lines and arrows leading to the connector 10 represented by a simple rectangle.

Concretely the connections are made in the form of tracks carried by the other side of the support 8 and the connector is also carried by the other face and disposed at the center of the support.

The double-sided circuit technology is well known to those skilled in the art. As an indication, we have shown on the figure 3c the support cut at the level of the initiation means 9c. It can be seen that the studs 14a and 14b partly cover the bridge 15. The stud 14a, which is connected to the common circuit C, covers a metal deposit which constitutes the circular track 20a, deposited on the support 8 on the same side as the means of initiation.

A bore 36 passes through the support 8. It allows to connect the two faces of the latter. This piercing, or hole metallized in the language of the skilled person, is filled by a metal deposit 37 which is connected by a weld 39a to the pad 14b and by a weld 39b to a conductive track 38 carried by the underside of the support 8 and which leads to the connector 10.

Those skilled in the art will easily define the geometry of the tracks which, made at the level of the lower face of the support, will make it possible to connect the different control circuits S to the connector 10. It will therefore suffice to realize, at the level of each of the groups of means Initiation by the upper face of the support, a bore passing through the support 8 at one of the pads 14b of one of the initiation means of the group in question. Moreover, another drilling made at the level of the pad 14a of the initiation means 9c ensures the passage of the common conductor C.

The electronic control means 11 has not been described in detail because it does not constitute the object of the present invention. In a conventional manner this control means is designed to send an electric firing current between the common conductor C and one or more of the control conductors S1, S2, S3 .... Si. The choice of drivers who will or will not be powered will be made using a means of programming and / or selection appropriate to the operational needs of the operating mode of the military head.

The different modes of operation of the device according to the invention will now be described with reference to the Figures 5a, 5b , 5c and 5d .

If it is desired to initiate the warhead 1 so that it generates a core it is necessary to ensure an axial ignition of the explosive charge 2.

For this, the electronic control means sends a firing current to the only initiation means 9a, therefore between the common conductor C and the control conductor S1 ( figure 5a ).

If one wishes to initiate the military head so that it generates a hollow charge jet, it is necessary to initiate it in a circular crown. The figure 5b shows how it is possible to initiate such an operation. For this purpose the electronic control means sends a current firing between the common conductor C and all S3 control lines _a, S3 _b, S3 _c and S3 _d and all insulated control conductors If _b, Si _c, If _d and Si _e . So all the means of initiation 9 of the crown external 18 are simultaneously initiated, both those in groups 28, 29, 30 and 31 that are isolated 9b, 9c, 9d and 9e.

The initiation device described here comprises twelve groups of initiation means each of which can be actuated separately. It is therefore possible to obtain other modes of operation of the warhead.

For example, figure 5c shows an initiation mode in which all the initiating means distributed along the arms 19a and 19b are simultaneously controlled, as well as the isolated means 9b, 9c, 9d and 9e as those of the rings 22, 23 and 24.

Such an initiation mode leads to the fragmentation of the coating and to the projection of these fragments according to the direction of action DA of the charge ( figure 1 ).

The figure 5d shows an initiation mode in which all the initiation means of the sector 28 of the peripheral ring 18 are simultaneously controlled. Such an initiation mode leads to the projection of the fragments of the envelope 3 of the charge in a preferred direction DB substantially radial and opposite to the initiated sector.

It can therefore be seen that the device according to the invention makes it possible to obtain, in a simple manner, a means for ensuring the initiation of a multi-function military head.

Indeed, the technologies used are those that make it possible to achieve the individual initiation means. It is not more expensive to implement them to ensure also the realization of all the conductive tracks and thus obtain a complete component ensuring the desired effects.

Furthermore, the positioning of the various initiation means relative to each other is ensured in a reliable and reproducible manner by the simple design of the device.

The support bearing its connector 10 is then placed in a simple manner inside its housing 6. The loading of the detonating composition 12 is performed according to the usual loading procedures for the initiators (or by gluing a sheet explosive plastic on the support). The positioning accuracy of the initiation means with respect to the casing of the military head 1 is finally obtained simply by a single operation of fixing the casing 6 on the casing 3.

Moreover, the axial size of the device according to the invention is reduced. The height E can thus be less than 5 mm, which allows the production of extremely compact military heads.

Various variants are possible without departing from the scope of the invention. It is thus possible to produce initiation devices having a number of different initiation means or groups of initiation means.

It will also be possible to define different distributions for the initiation means.

It is also possible to produce a device according to the invention in which the initiation means 9 are hot-wire or exploded initiators. After manufacture of the support 8 carrying the conductive tracks, it will then be necessary to solder son between the pads of each initiator. Such a mode is however less interesting because more expensive to achieve.

It is also possible as mentioned in the preamble to achieve with the invention an initiation device for gas generating compositions.

Claims (7)

1. An ignition device (5) for an explosive charge or pyrotechnic composition, such device comprising at least two ignition means (9) carried by a single insulating support (8) and connected to a power source, such device characterized the support (8) carries also the conductors ensuring the connection of the ignition means (9) to the power source, the initiation means comprising studs (14) supported by the surface of the support (8) and connected by means of semiconductor (15) or resistive (16) bridge, the conductors being realised by conductive strips carried by a wall of the support (8), the support comprising at least a first group (17) of ignition means (9) spaced over a peripheral crown (18) and at least a second group of ignition means spaced over at least a diametral arm (19a, 19b), all the ignition means (9) comprising a first contact stud (14a) connected to a common conductor (C) and the support comprising also two other control conductors (S1, S2), which are each connected to second contact studs (14b) of two groups of separate ignition means (9).
2. An ignition device according to Claim 1, characterized by the fact that the ignition means (9) incorporate at least one semiconductor bridge (15).
3. An ignition device according to one of Claims 1 or 2, characterized by the fact that it comprises ignition means (9) spaced over a peripheral crown (18) and on two orthogonal diametral arms (19a, 19b).
4. An ignition device according to one of Claims 1 to 3, characterized by the fact that it comprises at least a first control conductor (S1) ensuring the ignition of an axial ignition means (9a).
5. An ignition device according to Claim 4, characterized by the fact that it comprises at least a second control conductor (S2_a, S2_b, S2_c) ensuring the ignition of a first crown (22) of ignition means (9) spaced on arms around the axial ignition means (9a).
6. An ignition device according to one of Claims 4 or 5, characterized by the fact that it comprises at least a third control conductor (S3_a, S3_b, S3_c, S3_d) ensuring the ignition of a sector (28, 29, 30, 31) of ignition means (9) of the peripheral crown (18).
7. An ignition device according to Claim 6, characterized by the fact that the peripheral crown (18) comprises four sectors (28, 29, 30, 31) of ignition means (9), each able to be ignited separately by specific control conductors.

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