US20050241521A1

US20050241521A1 - Device enabling the ignition of two explosive charges and warhead implementing such an ignition device

Info

Publication number: US20050241521A1
Application number: US11/067,898
Authority: US
Inventors: Michel Vives; Jean-Paul Duparc
Original assignee: Giat Industries SA
Current assignee: Giat Industries SA
Priority date: 2004-03-18
Filing date: 2005-03-01
Publication date: 2005-11-03
Also published as: FR2867848A1; EP1577635B1; ATE469334T1; FR2867848B1; ES2346663T3; DE602005021420D1; EP1577635A1

Abstract

A device enabling the ignition of at least two explosive charges using a single detonator, device wherein it comprises at least a first pyrotechnic booster that is ignited by the detonator, a first booster that firstly ignites a first explosive charge by projecting a casing onto it and which is secondly connected to a second explosive charge by at least one detonation wave transmission booster.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention
The technical scope of the invention is that of devices enabling the ignition of at least two explosive charges using a single detonator.
2. Description of the Related Art
It is known, for example in the field of quarry explosives, to ignite several explosive charges using a single detonator. This detonator is connected to the different explosive charges by detonation wave transmission cords.
With such a solution, if the different charges are required to be detonated simultaneously, it is necessary for cords of identical length to be provided between the detonator and the different explosive charges.
This solution is not well adapted to the design of an ignition device for a piece of ammunition, for example for a splinter-generating warhead.
Indeed, it would in this case be necessary for substantial lengths of cord to be housed in the vicinity of the ammunition's explosive charge.
The aim of the invention is to propose an ignition device that is simple in design, compact and reliable ensuring the ignition of two explosive charges (namely a piece of ammunition) using a single detonator.
Thus, the invention relates to a device enabling the ignition of at least two explosive charges using a single detonator, device characterized in that it comprises at least a first pyrotechnic booster that is ignited by the detonator, a first booster that firstly ignites a first explosive charge by projecting a casing onto it and which is secondly connected to a second explosive charge by at least one detonation wave transmission booster.
According to another characteristic, the path of the projected casing will be of a length such that the ignition of both explosive charges will be practically simultaneous.
Advantageously, the first booster will be cylindrical and surrounded by a casing, also cylindrical, the projection of the casing occurring through an annular cavity arranged in the first explosive charge.
Furthermore, at present it is necessary for splinter-generating warheads to be designed that have several different modes of operation, programmable according to operational needs.
Warheads are sought to be made, for example, which in order to destroy a reinforced target (for example a missile nose cone) generate a cone of splinters focused in the vicinity of a radial plane of the warhead. Classically, these “focused cone” warheads are obtained by simultaneously igniting the warhead at both ends. Ignition is considered to be simultaneous when the deviation between both ignitions is less than or equal to 2 micro seconds.
To be able to destroy targets with little protection (such as command posts or communication boosters) these same warheads must, additionally, be able to generate an omni directional cone of splinters. It is classical to produce such a cone by igniting the warhead at only one of its ends.
Known solutions implement igniters, placed at each of the end faces of the warhead and controlled by a single electronic priming device.
These solutions require complicated electrical connections. Furthermore, the reliability of the simultaneity of the ignition depends on several factors: the reliability of the electronic system controlling the simultaneous ignition and the reliability of the two igniters.

SUMMARY OF THE INVENTION

The invention thus also relates to a warhead of simple design, that is compact and reliable, and which, thanks to the ignition device according to the invention can be made to operate under two different modes.
Thus, the invention also relates to a splinter-generating warhead implementing an ignition device such as that described previously, warhead characterized in that it comprises a block of loading explosive able to be ignited at one of its ends or the other by a first and/or second igniting explosive charge, the first igniting charge being able to be ignited by the projection of a casing surrounding the first booster and the second igniting explosive charge being able to be ignited by means of at least one detonation wave transmission booster connecting it to the first booster.
The loading explosive block may incorporate an axial channel inside which the detonation wave transmission booster will pass.
The splinter-generating warhead according to the invention may incorporate an insulating sheath placed in the axial channel and surrounding the transmission booster.
The warhead may comprise a first detonator placed so as to be able to ignite the first booster, such first detonator being activated by a priming fuse.
According to one variant, the first igniting explosive charge may be directly ignited by a second priming means separate from the first booster.
The second priming means may comprise at least three detonating primers evenly spaced angularly and arranged opposite a crown of the first explosive charge.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will become more apparent from the additional description that follows of a particular embodiment, such description being made with reference to the appended drawings, in which:
FIG. 1 is a section view of a warhead according to the invention implementing the ignition device according to the invention,
FIGS. 2 a and 2 b are two views schematizing the operation of the warhead according to the invention respectively in its focused splinter cone and scattered splinter cone modes.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

With reference to FIG. 1, a warhead 1 according to the invention comprises a block 2 of loading explosive that is placed into a splinter-generating casing 3. The casing 3 is closed at each end by a cover 4 a, 4 b. The explosive block 2 incorporates a cavity 5 a, 5 b at each of its ends that receives an igniting explosive charge 6 a, 6 b.
The block 2 further incorporates an axial channel 7 that connects the two cavities 5 a and 5 b .
The first cavity 5 a encloses a tablet of a first igniting explosive charge 6 a. This first charge is constituted, for example, by a relatively insensitive explosive such as an explosive associating triaminotrinitrobenzene and a thermoplastic binder, explosive such as that described by patent FR2671549. This first charge 6 a incorporates a cylindrical housing 8 inside which a first detonation booster 9 a is placed, this being placed opposite a first detonator 10 a. The booster 9 a will be constituted, for example, by an explosive associating cyclonite and wax. This booster is cylindrical and coaxial to the housing 8.
The detonator 10 a is connected by a filament to a priming fuse 14.
The first booster 9 a is surrounded by a cylindrical casing 11, for example metallic, which is intended to be projected radially against the internal cylindrical wall of the housing 8 when the first booster 9 a is ignited. The space 12 separating the casing 11 and the first charge 6 a may be either empty or filled with an annular layer of compressible synthetic foam.
The projection of the casing 11 thus ensures the ignition of the first charge 6 a by the first booster 9 a with a delay that depends on the diameter of the housing 8, on the nature and thickness of the casing 11 as well as on the presence or absence of a compressible material inside the space 12.
Furthermore, a washer 21 (for example metallic) is placed between the end of the booster 9 a and the igniting explosive charge 6 a. This washer enables a direct axial ignition of the charge 6 a by the booster 9 a to be avoided.
The second igniting explosive charge 6 b is of the same composition as the first charge 6 a. It is, moreover, ignited by a second detonation booster 9 b which is itself ignited by the first booster 9 a and by means of a detonation wave transmission booster 13, placed between the two boosters 9 a and 9 b.
Transmission boosters are well known to the Expert. They generally comprise a tube 13 a of plastic material enclosing a fine layer of explosive and carrying a booster 13 b, 13 c at each end.
These cords ensure the transmission of the detonation wave between two boosters at a velocity of around 7,000 m/s.
The cord 13 is separated from the explosive block 2 by an insulating sheath 15 placed in the axial channel 7 and surrounding the transmission booster 13.
This sheath is made, for example, of a plastic material. Its purpose is to protect the explosive block 2 against projections from the cord 13.
According to another characteristic of the warhead according to the invention, the first igniting explosive charge 6 a may be ignited directly by second priming means separate from the first booster 9 a.
These second priming means here comprise at least three detonating primers 10 b, evenly spaced angularly, and placed opposite a crown 16 of the first explosive charge 6 a.
The three peripheral detonators 10 b are carried (as indeed is the first detonator 10 a) by a support 17 integral with the cover 4 a. They are connected (as is the detonator 10 a) to the priming fuse 14 by filaments.
The operation of the warhead 1 and of its ignition device will now be described with reference to FIGS. 2 a and 2 b.
FIG. 2 a shows one mode of operation of the warhead 1 in the “focused splinter cone” mode. The priming fuse then controls the ignition of the axial detonator 10 a.
The first booster 9 a is then ignited and in turn ignites the second explosive charge 6 b by means of the transmission relay 13 and of the second booster 9 b.
In parallel, the ignition of the first booster 9 a causes the casing 11 to be projected through the space 12.
This casing impacts against the internal cylindrical surface of the housing 8. The shock thus causes the ignition of the first explosive charge 6 a.
The projection velocity of the casing 11 is of around 2,000 m/s whereas the detonation velocity via the transmission booster 13 and the second booster 9 b is of around 7,000 m/s. However, the distance that the projected casing 11 must cover is much less than that to be covered by the detonation wave conducted by the axial booster 13.
Because of the differences in velocity, it is thus possible for the device to be dimensioned such that there is a simultaneous ignition of the two explosive charges 6 a and 6 b.
Ignition is considered to be simultaneous when the deviation between both ignitions is less than or equal to 2 micro seconds.
Somebody skilled in the art will easily dimension such an ignition device by acting namely on the diameter of the housing 8, on the thickness of the projected casing 11, on the mass of the first booster 9 a as well as on the presence or absence of a filling material in the space 12.
Since the two igniting explosive charges 6 a and 6 b are ignited simultaneously, the explosive block 2 is ignited at its two ends and two detonation wave fronts 18 a and 18 b are propagated in the explosive block 2 in directions that converge towards a median plane 19, leading to a projection of the casing 3 splinters in the direction of this median plane 19 (arrows E schematize the projection velocities for the splinters).
FIG. 2 b shows the operation of the warhead 1 in its “scattered splinter cone” mode. The priming fuse 14 then controls the ignition of the crown of peripheral detonators 10 b.
These detonators then ignite directly the first explosive charge 6 a. The first booster 9 a is not ignited. A single detonation wave front 18 c progresses, in this case, through the explosive block 2. This results in a dispersion of the splinters in a relatively homogeneous manner inside a cylindrical volume around the axis 20 of the warhead.
Different variants are possible without departing from the scope of the invention.
It is thus possible for the peripheral detonators 10 b to be replaced by a priming device that only has one axial detonator 10 a and a mobile screen (not shown) able to move in the housing 8, placed between the casing 11 and the first explosive charge 6 a.
In this case, when the warhead is required to operate in its “focused cone” mode, operation is effected as described previously with reference to FIG. 2 a.
When the warhead is required to operate in its “scattered cone” mode the screen is positioned (before ignition) in the housing 8. This may be carried out using a suitable actuator (such as a stepping motor).
When the detonator is ignited, it controls the ignition of the second explosive charge 6 b by means of the transmission booster 13 and the second booster 9 b.
Because of the presence of the screen, the casing 11 cannot be projected onto the first explosive charge 6 a. The explosive block 2 is thus ignited at one end only by the second explosive charge 6 b.
This results in a dispersion of the splinters having an orientation that is symmetrical with respect to a median plane 19 of that shown in FIG. 2 b.

Claims

1. A device enabling the ignition of at least two explosive charges using a single detonator, wherein said device comprises at least a first pyrotechnic booster that is ignited by said detonator, said first booster that firstly ignites a first explosive charge by projecting a casing onto said charge, said first booster being secondly connected to a second explosive charge by at least one detonation wave transmission booster.

2. An ignition device according to claim 1, wherein the path of said projected casing is of a length such that the ignition of both said explosive charges is practically simultaneous.

3. An ignition device according to claim 1, wherein said first booster is cylindrical and surrounded by said casing, also cylindrical, the projection of said casing occurring through an annular cavity arranged in said first explosive charge.

4. A splinter-generating warhead implementing an ignition device according to claim 1, wherein said warhead comprises a block of loading explosive able to be ignited at one of its ends or the other by a first and/or second igniting explosive charge, said first igniting charge being able to be ignited by the projection of a casing surrounding said first booster and said second igniting explosive charge being able to be ignited by means of at least one detonation wave transmission booster connecting it to said first booster.

5. A splinter-generating warhead according to claim 4, wherein said loading explosive block incorporates an axial channel inside which said detonation wave transmission relay passes.

6. A splinter-generating warhead according to claim 5, wherein it incorporates an insulating sheath placed in said axial channel and surrounding said transmission booster.

7. A splinter-generating warhead according to claim 4, wherein it comprises a first detonator placed so as to be able to ignite said first booster, said first detonator being activated by a priming fuse.

8. A splinter-generating warhead according to claim 7, wherein said first igniting explosive charge may be directly ignited by a second priming means separate from said first booster.

9. A splinter-generating warhead according to claim 8, wherein said second priming means comprise at least three detonating primers evenly spaced angularly and arranged opposite a crown of the first explosive charge.