FR2525763A1 - Hollow charge explosive for shell - uses prim charge to hold initiation delay and thermally bonded to secondary charge - Google Patents

Abstract

The loading of explosive is for a projectile of hollow charge type. It has a block of priming charge (15) of explosive which is thermally bonded to the main explosive charge (13) by a thermal process. The characteristics of the priming explosive are essentially the same as those of the main charge. The main charge extends annularly around the priming one and the interface, up to the rear (T,T') of the charge is cylindrical, coaxial, and of less diameter than that of the charge diameter. A compressed initiation relay (16) is fitted into the priming charge.

Description

 the present invention relates to improvements made to the loading of explosives and to the initiation of projectiles, in particular with a hollow charge and, in particular, the symmetry of said initiation.

 It is known that, among the many parameters which govern the operation of an explosive projectile, in particular 4 hollow charge, there are those which determine the quality of the detonation wave. For these parameters, it is necessary to reduce the asymmetry at the start as much as possible in order to obtain a hollow charge correctly directed along the axis of the charge.

This reduction in asymmetry can be achieved by several methods which can be combined - a better charge initiation by trying to achieve
a point source - a dispersion of heavy, powerful explosives such as hexos
gene or octogen for example, as low as possible, in
sectors located at the same 1, level "of the explosive charge
main (hexolite or octolite for example) - an improvement in the explosive initiation-explosive interface
main.

 The subject of the present invention is various improvements made to the loading of explosives and the initiation of projectiles, in particular of a hollow charge, intended for weapons systems such as, for example, rocket launchers, missiles, mortars, guns with a closed breech, recoilless cannons, rifles, grenades, multiple-element heads, submunitions, mines, etc., characterized in particular in that said projectile or said hollow charge is provided with an initiating block of explosive "welded" to the explosive of the main load, by a heat treatment specific to the invention.

 Thanks to this characteristic specific to the invention, the asymmetry of the detonation wave is eliminated or greatly reduced by improving the interface between the priming explosive and the main explosive (reduction or elimination of interface).

 To reduce any discontinuity in the formation of the detonation wave, the present invention proposes the use of a Sif priming exploit cast of the same kind as the main explosive, also cast (octolite for example); bypassing the screen, possibly used, is thus carried out in an explosive of the same kind (octolite for example).

 This particular method of ignition, according to the invention, of the projectile or the hollow charge, requires the use of a punctual initiation relay compressed, in hexocire or octocira for example, placed in a housing provided for this purpose. effect in the welded priming block according to the invention. It is also necessary that the content of the charge of the "welded" initiation according to the invention is similar to that of the rear face of the main explosive, in order to ensure continuity in the detonation speeds.

 According to the invention, two methods are provided for carrying out the "welding" of the priming block and the main load, using a heat treatment specific to the invention. However, other "welding" methods can also be used, without departing from the scope of the invention.

 According to a first embodiment, the initiating explosive is poured onto the main explosive previously supplied at a temperature which allows the surface fusion of the explosive added to the explosive already in place (approximately 700C) for a determined time, in the case of, for example, octolite or hexolite.

 According to a second embodiment, the priming block is poured separately into an appropriate tool, machined. And placed above the main explosive. According to the present invention, the assembly is then brought to temperature for a determined time (heat treatment) to ensure "welding" (approximately 700C, for example, in the case of octolite or hexolite).

 It is also recalled that in all cases the "welded" initiation according to the invention is of the same nature as the main explosive and, also in all cases, that there may or may not be, without departing from the scope of the invention, presence of detonation toric wave generator screen.

 The various characteristics and advantages of the invention appear from the description which follows. It relates to a hollow charge head with priming "welded" 1, disc-shaped, providing a toroidal annular wave. It is well specified that the invention applies to all other types and forms of priming, screen and detonation wave, central ignition, without screen and spherical wave for example, etc.

 It is also clearly stated that this is only an example and that all other projectiles, military heads, with or without hollow charge, all other construction methods, proportions, arrangements, can apply the invention or can be used without departing from the scope of said invention (conical hollow charge coating or other types of shape, with a constant thickness law or with a decreasing, progressive or other thickness law).

 The shaped charge described below, by way of nonlimiting example, and shown in the accompanying drawings, relates more particularly to a missile head. It is well specified that the invention applies, without departing from its scope, to heads for all other devices, rockets, mortar shells, closed-shell cannon shells, recoilless guns, rifles, grenades, submunitions , mines, etc.

During the description which follows, reference will be made to the appended drawings in which
- Figures 1 to 4 illustrate the different stages of a
method of producing the hollow charge with priming
"welded", according to the invention, cast in place
- Figures 5 to 9 illustrate the different stages of a
other method of making the shaped charge with amor
"welded" hole, according to the invention, machined separately before setting in
square.

- Figure 10 shows a longitudinal sectional view of a
shaped head (rear part only shown
without warhead) equipped with a priming "welded according to the invention
tion, with punctual initiator.

 In this variant, the main explosive envelops the “welded” cast ignition block, according to the invention.

 As stated above, the present invention proposes to reduce or cancel any asymmetry and discontinuity in the formation of the detonation wave.

 For this purpose, it uses for the initiation a cast explosive of the same kind as the main explosive, also cast, and realizes a real weld between the two explosives.

 Bypassing the screen, if it exists, takes place in an explosive of the same nature. In addition, according to the present invention, very sensitive ballistic characteristics of the explosives in contact are sought, hence, according to characterized by similar high explosive (octorite or hexolite) rates, both for the main charge and for the priming.

Reference is firstly made to FIGS. 1 to 4 which represent the different phases of producing a "welded" initiation according to the invention. It is a process of casting the priming block "in sit. This process includes 4 phases 1st phase
The wrapped 1 equipped with a coating 2 is filled with main poured explosive 3 (left part of FIG. 1). The disgorgement of place 4 of the boot block and the screen (visible at 5 on Fig. 2) is shown on the right side of the same figure 1.

2nd phase
'screen 5 is set up (figure 2).

3rd phase
The head is brought to temperature for a determined period and at a value which depends on the nature of the explosive, on the mass, on the dimensions and on the shapes. . - in the presence (for an octolite or hexolite load for example, this temperature is close to 700C).

 The initiating explosive 3 ′ is then poured, of the same nature, according to the invention, as the main explosive 3 (FIG. 3), also seeking, as said above, a similarity in the contents, power, characteristics. .. of the two loads. This is why the amount of explosive in the charge increase, its composition and lg settling conditions which determine the content of powerful explosive (hexogen or octogen for example) of the "welded" initiation 3 'according to the invention. are adjusted and adjusted so that this content is close to that of the main explosive 3 in the contact zone 6 of FIG. 3.

 This casting combined with the heat treatment specified above realizes, according to the invention, the "weld" between the initiation 3 'and the main load 3 according to the invention.

4th phase
After cooling, the AR face of the head is machined to the desired profile 5 ", in particular providing the housing intended to possibly receive the initiator relay 7 - preferably in compressed explosive - (Figure 4). The head is then closed (not shown) ).

 FIGS. 5 to a represent the different phases of another -rocd according to the invention, also producing a "welded" initiation. This other exemplary embodiment provides for the installation on the main load of a separately poured priming block.

1st phase
The priming block 8 is poured independently of the load in an appropriate tool (base 9, casing 10 (FIG. 5).

The characteristics of the 8 ′ charge (hexogen or octogen content for example, characteristics of the settling, composition, etc.) are, according to the invention, carried out to obtain a detonator of the priming block similar to that of the main explosive who should receive this boot.

2nd phase
the priming block 8 is machined to the desired profile (FIG. 6), making provision in 7 'for the place of the initiation relay, if any.

3rd phase
The main explosive 3 is poured into the head; we then machine, as before, the housing of the screen 5 and we put it in place (Figure 7). These operations are identical to those described above with reference to FIG. 2.

4th ~ phase
The load, equipped with its screen 5, is then started by the starting block 8 (FIG. 8).

5th phase
The initiation relay 7 is then put in place (FIG. 9) the head is then closed in a conventional manner (not shown).

In this case also, according to the invention, a "hard sou of the interfaces, main explosive-initiation, is carried out, by bringing the assembly to temperature. The temperature must be adjusted in value and in time so that that the geometry is preserved; the weld, according to the invention, will be obtained by the beginning of fusion of the tolite contained both in the initiation and in the main load.

 FIG. 10 represents another embodiment of a "welded" initiation according to the invention and concerns a hollow charge head 1 of conventional definition and of caliber a, shown without warhead; it includes an envelope 11, a conical coating 12, a main explosive 13 (hexolite or octolite for example), a screen 14, of diameter D1, forming an annular priming wave, a "welded" priming block, according to the invention "disc" 15, cast and machined in situ or cast and machined separately and then installed according to one of the methods described above, this priming block 15 being, according to the invention, of the same nature as the main load 13 (hexolite or octolite for example). An initiation relay 16 possibly completes said priming block 15.

In FIG. 10, a main load 13 has been shown, enveloping the "welded" initiating block 15. For this purpose, this main explosive 13 rises to the level of the AR wafer T-T ', like the priming 15 itself Under these conditions, the conventional plane interface, perpendicular to the longitudinal axis is replaced, according to the invention, by a cylindrical interface (diameter D1 # D2 diameter of the base of the head
Thanks to this arrangement, the symmetry of the detonation wave is improved. Furthermore, the cylindrical interface according to the invention has the effect of reducing, all other things being equal, the interface clearance, which contributes to reducing the asymmetry of the detonation wave, the aim sought by the invention.

Claims (7)

 1.- Loading of an explosive for a projectile, in particular with a hollow charge, intended for weapons systems such as launchers, missiles, mortar, cannons, recoilless cannons, mines, grenades, characterized in that it comprises a block of initiation (3 ', 8, 15) in explosive welded to the explosive of the main charge (3, 13), the welding or interpenetration of the interface between the two charges being carried out by an appropriate heat treatment.  2.- Loading according to claim 1, .caractérisé .en that the initiating explosive has characteristics substantially identical to those of the main explosive.  3.- Loading according to one of the preceding claims, characterized in that the main explosive (13) annularly wraps the welded priming block (15), the interface, up to the rear edge (T, T ' ) of the load, common to the two loads being cylindrical. coaxial, of diameter smaller than the diameter of the loading base.  rc, -. Load according to any one of the preceding claims, characterized in that the welded ignition is provided with a point initiation relay (7, 16), preferably compressed, determining and improving the initiation of the pyrotechnic chain.  5.- A method of manufacturing a load according to any one of the preceding claims, characterized in that flows in situ, the priming block (3 ') above the main priming (3) with setting possibly in place of the screen (5) and then applying said appropriate heat treatment to achieve the weld between the two loads.  6.- Method according to claim 5, characterized in that one regulates the in situ loading of the welded priming block, in particular the composition and nature of the explosives which constitute it, the quantities used, the settling characteristics , so as to obtain on the interface and in its vicinity characteristics of the two practically identical loadings, favoring the welding.  7.- Method according to any one of claims 1 to 4, characterized in that the priming block (8) flows independently of the main charge (3), the priming block is put in place. on the main charge after possible installation of the screen (5) then there is the initiation relay (7) and a welding of the interfaces is carried out, main explosive-initiation by application of said appropriate heat treatment.  8.- Method according to any one of the preceding claims, characterized in that the heat treatment consists of heating to a temperature close to 700C for explosives based on tolite, the heating time at this temperature being chosen according to other characteristics of the load, such as in particular mass, shape, explosive.