Patent Application
20080092764
The invention will become more apparent from the following description of the different embodiments, such description being made with reference to the appended drawings, in which:
a is a schematic view of a semiconductor bridge element implemented in one embodiment of the device according to the invention,
b is a schematic view of a resistor bridge implemented in another embodiment of the ignition device according to the invention,
c is a partial cross section of the support for an ignition means,
a, 5b, 5c and 5d are views analogous to that in
With reference to
The demonic properties of the explosive and the geometry of the liner 4 are selected so that this warhead can have several different modes of operation according to the mode of ignition selected. These properties are well known to the Expert and will not be described here since they are not the subject of the present invention. By way of example, reference may be made to patent EP1164348 which describes such a multi-function warhead.
The warhead 1 may be ignited by an ignition device 5. The latter comprises a cylindrical case 6 having substantially the same external diameter as the casing 3 of the warhead 1 and closed by a flat bottom 6a in which an axial opening 7 is made.
In accordance with the invention, the case 6 encloses a single insulating support 8 carrying the ignition means 9. A connector 10 is fastened at a rear face of the support 8 which allows the ignition device 5 to be connected to electronic control means 11 incorporating a power source enabling the ignition device 5 to be activated. The connector 10 comes out of the case via the opening 7.
The case 6 also encloses a detonating pyrotechnic composition 12, for example compressed hexanitrostilben (HNS) or cyclonite (RDX), which is applied by compression against the support 8. A sheet of plastic explosive, for example an explosive based on rubber and pentrite (known as Formex) may be used for the composition 12.
The case 6 is fastened to the casing 3 by linking means, not shown here, for example by an external ring screwed or crimped both onto the case 6 and the casing 3 so that the warhead 1 and ignition device 5 may form a single component.
Furthermore, as may be more particularly seen in
The support 8 may be more particularly seen in
a and 3b show enlarged illustrations of two different embodiments of such ignition means 9.
The contact studs are of a width opposite the bridge which is less than their width at a distance from the bridge. Such an arrangement facilitates the priming of the ignition plasma between the studs.
Such a semiconductor bridge is well known to the Expert. Reference may be made, for example, to patent EP0711400 which describes an igniter using a semiconductor bridge.
When a specific electrical voltage (depending on the dimensional and physical characteristics of the material used to make the bridge 15) is applied between the contact studs 14, a plasma is generated through the bridge 15 and the resulting energy ensures the ignition of the detonating composition in contact with the bridge.
b shows another embodiment of ignition means 9. In this embodiment, the studs 14 are connected by a resistor conductor element 16 (made, for example, of gold). In this embodiment (also well known to the Expert) it is the heating by Joule effect of the resistor element 16 (or its explosion) which ensures 7410 the ignition of the detonating composition.
According to a preferred embodiment, the different ignition means 9 will be applied to the support 8 using the same technology as for the production of integrated circuits.
It is, in fact, quite conventional to use this technique to make a plurality of ignition means (using semiconductor or resistor bridges) on the same support, such means being thereafter cut, for example, by laser to be integrated individually, each in its own case.
In accordance with the invention, this technique will be used to make a support carrying all the ignition means (following specific geometric spacing which will be described hereafter) as well as the conductors (or conductor strips) which ensure (via the connector 10) the linking of the ignition means 9 to a power source incorporated in the control means 11.
The support 8 may thus be constituted by a disc of amorphous silicon on which the ignition means as well as the conductor strips will be made by metallization and/or vacuum deposition.
The support 8 also supports a second group of ignition means 9 spaced over at least one diametral arm.
Here, there are two diametral arms 19a and 19b each incorporating six ignition means 9. Note that the ends of the diametral arms pass via the ignition means 9b, 9c, 9d and 9e which belong to the peripheral crown 18.
As may be seen in
Thus, all the ignition means incorporate a fist contact stud 14a which is connected to a common conductor C (all the studs connected to the common conductor are shown hatched on
Furthermore, the upper face of the support 8 has other conductor strips enabling the second contact studs 14b of a certain number of separate ignition means 9 to be connected together.
Thus, there are several groups of igniters 9 linked together and able to be simultaneously initiated via specific control conductors.
There is thus a first control conductor S1 which ensures the initiation of axial ignition means 9a.
There is also a second control conductor S2a which ensures the initiation of a first crown 22 of four ignition means spaced on arms 19a and 19b and around the axial ignition means 9a. The terminals 14b of these igniters are all linked to one another by a portion of circular strip 25.
Similarly, there are control conductors S2b and S2c which ensure the initiation of two other crowns 23 and 24 of four ignition means spaced over arms l9a and 19b and around the axial ignition means 9a. The terminals 14b of these igniters are also linked together by a portion of circular strip, respectively 26 and 27.
There is lastly a third control conductor S3a which ensures the initiation of a sector 28 of ignition means 9 all located on the peripheral crown 18.
The device shown in
Each of these sectors is controlled by a specific control conductor (respectively S3a, S3b, S3c and S3d). At each sector, the contact studs 14b of the igniters are all linked together by a portion of circular strip. These portions of strip are marked 32, 33, 34 and 35 on the Figure.
Lastly, as described previously, on the peripheral crown there are four isolated igniters 9b, 9c, 9d and 9e positioned at the ends of arms 19a and 19b. Each of these igniters is controlled by a specific control conductor Sib, Sic, Sid and Sie.
All the control conductors are linked to the connector 10 which thus comprises at least 13 prongs.
These connections are shown schematically in
In practical terms, the connections are made in the form of strips carried by the other face of the support 8 and the connector is also carried by the other face and is placed at the centre of the support.
Double face circuit technology is well known to somebody skilled in the art. By way of illustration,
A drill hole 36 goes through the support 8. It enables the support's two faces to be linked. This drill hole, or plated through hole as it is termed by the Expert, is filled by a metallic deposit 37 connected by a weld 39a to contact stud 14b and by a weld 39b to a conductor strip 38 carried by the lower face of the support 8 and which leads to the connector 10.
The Expert will easily define the geometry of the strips which, made on the lower face of the support, will enable the different control circuits S of the connector 10 to be linked. Thus, in each of the groups of ignition means carried by the upper face of the support, a drill hole merely has to be made through the support 8 at one of the contact studs 14b of one of the ignition means in the group in question. Furthermore, another drill hole made at the contact stud 14a of ignition means 9c will ensure the passage of the common conductor C.
The electronic control means 11 have not been described in detail since they do not form the subject of the present invention. Classically, these control means are designed to send an electrical firing current between the common conductor C and one or several of the control conductors S1, S2, S3 . . . Si. The selection of the conductors to be powered will be made using programming and/or selection means suited to the mode of functioning operational needs of the warhead.
The different modes of functioning of the device according to the invention will now be described with reference to
If the warhead 1 is required to be ignited so as to generate a slug, the axial priming of the explosive load 2 must be ensured.
For this, the electronic control means sends a firing current only to ignition means 9a, thus between the common conductor C and the control conductor S1 (
If the warhead is required to be ignited so as to generate a shaped charge dart, it is necessary for it to be ignited following a circular crown.
The ignition device described here incorporates twelve groups of ignition means each able to be activated separately. It is thus possible to obtain other modes of functioning for the warhead.
By way of example,
Such a mode of ignition leads to the fragmentation of the liner and to the projection of these fragments in the direction of action DA of the charge (
d shows a mode of ignition in which all the ignition means of sector 28 of the peripheral crown 18 are activated simultaneously. Such a mode of ignition leads to the projection of fragments of the casing 3 of the charge in a privileged direction DB that is substantially radial and opposed to the sector ignited.
As we can see, the device according to the invention enables means to be obtained simply which ensure the ignition of a multi-function warhead.
Indeed, the technologies implemented are those used to produce individual ignition means. It is no more costly to implement them to additionally ensure the production of all the conductor strips thereby obtaining a full component ensuring the required effects.
Furthermore, the positioning of the different ignition means with respect to one another is ensured in a reliable and reproducible manner by the device's simple design.
The support carrying its connector 10 is then simply set into place inside its case 6. The detonating composition 12 is loaded according to the usual loading procedures for igniters (or by bonding a plastic explosive sheet onto the support). Positioning accuracy for the ignition means with respect to the warhead casing is finally obtained by the single operation of fastening the case 6 onto the casing 3.
Furthermore, the axial volume of the device according to the invention is reduced. The height E may thus be less than 5 mm which enables extremely compact warheads to be produced.
Different variants are possible without departing from the scope of the invention. It is thus possible for ignition devices to be made that have a different number of ignition means or groups of ignition means.
Different spacing may thus also be defined for the ignition means.
It is thus also possible for a device to be made according to the invention in which the ignition means 9 are hot wire or exploded wire igniters. After manufacture of the support 8 carrying the conductor strips, it will thus be necessary for the wires to be welded between the contact studs of each igniter. Such a mode is, however, less advantageous since it is more costly to perform.
It is thus also possible, as mentioned in the preamble, to produce an ignition device according to the invention for gas-generating compositions.
| Number | Date | Country | Kind |
|---|---|---|---|
| 04.13471 | Dec 2004 | FR | national |
