EP0881458B1 - Container for propellant charge - Google Patents

Description

The technical field of the invention is that of ammunition propellant charge boxes.

EP314547 discloses a munition comprising a feathered projectile and a case, ammunition in which the propellant charge has a surrounding portion the empennage and disposed in a housing linked to the projectile.

The case described by this document is made in one combustible material similar to that of the socket.

One of the main disadvantages of this type of case is its manufacturing and implementation cost.

This material is also fragile and may degrade during aging of the ammunition, releasing then part of its propellant charge and modifying the ballistic characteristics of the ammunition.

The use of a combustible material for the case also presents risks during the manufacture of loading as well as during the storage phases of components.

Furthermore, the risks inherent in the use of a combustible material require the installation of specific facilities and procedures both for the manufacture of the case only for the storage of the material first.

Such fuel boxes have other disadvantages.

So, although combustible, the housing cover known may momentarily hinder the progression of the ignition flame in the very first moments of functioning of the propulsive system.

On the other hand, the fuel boxes cannot be reused after dismantling an ammunition for example for a return to the propulsion system level after a certain storage time. What causes costs additional.

Finally, it is impossible to define a box fuel that can adapt as well to ammunition in which the primer holder tube must pass through the cover to another munition in which the primer-carrying tube does not not pass through the cover. Indeed if we plan a drilling passing through the lid, the propellant powder may escape through it when the tube carries primer does not occupy the hole.

The patent US3098444 describes a destructible case for ammunition whose envelope comprises two superimposed layers: a pierced layer and a layer closing off the holes.

US Pat. No. 3,613,588 describes a housing made of plastic for the ignition charge of a recoilless weapon. This housing has a cylindrical casing adjusted to the tube the weapon and incorporating a housing containing a charge ignition.

It is the object of the invention to provide a housing for propellant charge not having such disadvantages.

Thus the invention provides a housing of simple design and inexpensive and making loading easier propulsion.

The housing according to the invention is made of a material inert and it ensures excellent load stability propellant to aging.

The housing proposed by the invention is also completely removable and reusable.

In addition, it improves the mechanical strength of the ammunition and in particular the resistance of the combustible case to tests fall.

Indeed, the proposed housing is rigid enough to maintain the propellant charge portion that it contains. It therefore transfers directly to the projectile the forces due to the inertia of the powder, thus protecting the combustible socket.

Finally the housing according to the invention can adapt to all types of ammunition and in particular those for which the primer holder tube has a length such that it reaches the level of the tail of the projectile.

Thus the invention relates to a housing for a charge propellant, for ammunition comprising a projectile and a socket, housing integral with the projectile and comprising a substantially cylindrical casing and a cover of closure, housing characterized in that the envelope cylindrical is made of plastic and that it is constituted by a trellis formed of strands delimiting openings passing through the envelope, the closure cover being made of plastic and comprising at least one opening.

The trellis is advantageously formed by repetition of a rectangular elementary mesh whose width is less than the diameter of one of the propellant powder grains intended to be put in place in the case.

The length of the elementary mesh rectangle may be parallel to the axis of the cylindrical envelope.

According to a preferred embodiment, the envelope cylindrical is obtained by winding a sheet plane.

The flat sheet may advantageously relate to one of its edges at least two tabs intended to cooperate with at least two lights carried by another edge of the sheet, so as to allow these edges to be joined and thus the constitution of the cylindrical envelope of the housing.

The housing may include means allowing its hanging on a connecting element secured to a projectile.

These attachment means may in particular be consisting of pins intended to penetrate into orifices carried by the connecting element.

Preferably, the cover may include several openings affecting the shape of lights delimited by arcs of circles having for axis the case axis, lights regularly distributed angularly.

According to another characteristic of the invention, the cover may have an axial circular opening having at least three flexible radial lamellae.

The cover will advantageously have a cylindrical rim external intended to cooperate with the cylindrical envelope of the housing, and this flange may include at least three hooks regularly distributed angularly and intended for cooperate with housings carried by the envelope cylindrical case to lock the cover and envelope.

According to an alternative embodiment of the invention, and when the case is intended to be made integral with a connecting element, itself integral with the projectile and intended to be fixed by riveting to a socket, the casing cylindrical will be able to carry bowls regularly angularly distributed and intended to come next to rivet fixing holes which are carried by the element link.

• la figure 1 est une vue en coupe simplifiée d'une munition comportant un boítier pour charge propulsive selon l'invention, munition représentée avant solidarisation de la douille et du projectile,
• la figure 2 est une vue du boítier selon l'invention fixé à une partie arrière de projectile, la demi vue de gauche (figure 2a) montrant le boítier en coupe, et la demi vue de droite (figure 2b) montrant le boítier en vue externe,
• la figure 3 est une vue du couvercle du boítier seul,
• la figure 4 est une coupe de la figure 3 suivant le plan AA,
• les figures 5 et 6 sont des vues de détails montrant le moyen d'accrochage du boítier sur l'élément de liaison (figure 5) et le moyen de verrouillage du couvercle sur le boítier (figure 6),
• la figure 7 est une vue d'un deuxième mode de réalisation du boítier selon l'invention fixé à une partie arrière de projectile, la demi vue de gauche (figure 7a) montrant le boítier en coupe, et la demi vue de droite (figure 7b) montrant le boítier en vue externe,
• la figure 8 montre la feuille ajourée plane permettant de réaliser l'enveloppe du boítier,
• la figure 9 est une vue de détail des cuvettes portées par le boítier,
• les figures 10a et 10b sont des vues de détails montrant les moyens de solidarisation des bords de la feuille ajourée plane permettant de réaliser le boítier, la figure 10a représentant les deux bords avant solidarisation et la figure 10b montrant ces deux bords après solidarisation.

Other advantages of the invention will appear on reading the description which follows of different embodiments, description made with reference to the accompanying drawings and in which:

• FIG. 1 is a simplified sectional view of an ammunition comprising a casing for a propellant charge according to the invention, ammunition shown before the socket and the projectile are joined together,
• Figure 2 is a view of the housing according to the invention attached to a rear projectile part, the half view from the left (Figure 2a) showing the housing in section, and the half view from the right (Figure 2b) showing the housing in view external,
• FIG. 3 is a view of the cover of the case alone,
• FIG. 4 is a section of FIG. 3 along the plane AA,
• FIGS. 5 and 6 are detail views showing the means for attaching the housing to the connecting element (FIG. 5) and the means for locking the cover to the housing (FIG. 6),
• Figure 7 is a view of a second embodiment of the housing according to the invention fixed to a rear projectile part, the half view from the left (Figure 7a) showing the housing in section, and the half view from the right (Figure 7b) showing the case in external view,
• FIG. 8 shows the flat perforated sheet allowing the envelope of the case to be produced,
• FIG. 9 is a detailed view of the bowls carried by the housing,
• Figures 10a and 10b are detail views showing the means of securing the edges of the flat perforated sheet for making the housing, Figure 10a showing the two edges before securing and Figure 10b showing these two edges after securing.

Figure 1 shows a general propellant charge of ammunition of the type described by patent EP314547. A such loading comprises an element before 1a and an element rear 1b. The element before the consists of a housing 2 which contains the rear of a tailed projectile 3 (of which only the tail is represented here) and a first charge propellant 4.

The rear element 1b comprises a socket 5 integral a base 6 and which contains a second propellant charge 7. An igniter tube 8 is integral with the base 6 and it extends longitudinally inside the second load 7.

The socket 5 can be a combustible socket. She is not completely filled with propellant powder and a height H is formed between the upper surface 9 of the second propellant charge 7 and the free end 10 of the socket 5. The free space 11 is intended to receive the box 2 containing the first propellant charge 4 integral of the projectile 3.

Such a structure is described in detail in the patent EP314547 the whole description of which is included here by reference. We will refer to this patent in particular for the description of the loading and assembly process which is used to make the ammunition.

Figures 2a and 2b show a housing 2 for charging propellant according to a first embodiment of the invention.

The housing 2 is made of a plastic material, by example in Polypropylene or polyethylene copolymer. he includes a cylindrical casing 12 and a cover closure 13. According to an essential characteristic of the invention, the envelope is formed by a lattice formed strands 14a, 14b delimiting openings 15. Here the strands 14a and 14b are orthogonal, the strands 14a are straight and parallel to the axis 16 of the housing (therefore of the socket of the ammunition). The strands 14b are circular and centered on axis 16. The openings are therefore openings rectangular

The trellis is therefore generally formed by repetition of a rectangular elementary mesh constituted by a opening surrounded by four strands which delimit it, the length of the rectangle of the mesh being parallel to the axis 16 of the cylindrical casing 12.

The section of the strands will be chosen such that the pressure propellant gases developed during the firing of ammunition causes its rupture. Such a trellis structure ensures therefore the rigidity and lightness of the housing while promoting destruction of the case when fired in conditions eliminating any risk of residues in the chamber of the weapon.

The openings also make it easier to flame passage radially which improves combustion of the fuel socket 5.

The orientation of the openings 15 with their length parallel to the axis of the case gives the case flexibility which facilitates its manufacture by winding from a sheet as will be described later.

The openings 15 will be given a width less than the diameter of the powder grains intended to be placed in the housing to constitute the first propellant charge 4, this in order to ensure the maintenance of the grains of powder by The box. Such a provision will be useless in the case of the use of a propellant charge in bundles.

The mesh dimensions are defined so as to ensure maximum openwork area while ensuring sufficient rigidity for the housing and grain maintenance powder.

Another advantage of such an envelope structure is that, during loading, the powder grains are supported randomly around the edges of the openings 15. There are results in grain storage with orientations random, so a filling of the case without creation privileged stacks likely to disrupt the interior ballistics during the shooting.

The housing 2 is closed by a cover 13 which is also visible in Figures 3 and 4.

This cover is also made of plastic. It has an axial circular opening 17, as well as several other openings 18 affecting the shape of lights delimited by arcs of circles 19a, 19b having for axis axis 16 of the housing. These lights are regularly distributed angularly.

The function of the lights 18 is, on the one hand to facilitate ignition of the propellant charge contained in the housing from the load contained in the socket, and on the other hand weaken the lid to promote its fragmentation when firing.

The cover 13 also has a cylindrical rim external 20 intended to cooperate with the cylindrical envelope 12 of the case.

The rim 20 carries at its internal surface intended to come next to the envelope 12 at least three hooks 21 regularly distributed angularly (here eight hooks). These hooks 21 are intended to cooperate with housings 22 carried by the cylindrical casing 12 for ensure axial locking of the cover 13 and envelope 12.

Figure 6 shows in detail this means of locking (detail marked by arrow B in the figure 2a). The hooks carry a bevelled profile facilitating the introduction of the cover on the envelope 12.

The axial opening 17 of the cover 13 has at least three flexible radial strips 23 (here six strips).

These strips are visible in Figures 3 and 4, they extend radially through the opening 17 and can be folded to let an igniter tube pass as will be described later with reference to the figures 7a, 7b.

The length of the strips 23 is chosen such that the diameter of the circle defined by their free ends either less than the diameter of the grains of powder intended to come fill the box 2. The propellant charge cannot therefore not escape out of box 2 through the opening axial 17.

The housing according to the invention is fixed by its part upper 2a to a connecting element 24 integral with a projectile (see Figures 2a, 2b).

This connecting element 24 will for example be a piece made of plastic material which includes a bead 25 which is housed in an annular groove 26 of the projectile 3, a portion conical 24a and a cylindrical portion 24b substantially at diameter of the socket.

Such a connecting element is described for example by the Patent EP307307.

The housing 2 includes means allowing its attachment to the connecting element 24. This attachment is completely reversible and removable.

These attachment means are here constituted by pins 27 intended to penetrate into holes 28 carried by the connecting element 24. FIG. 5 shows in detail what attachment means (detail marked with arrow C on the Figure 2a). The pins are cylindrical, they bear a bevelled profile which facilitates their installation in the holes 28.

Envelope 12 and cover 13 can easily be made by injection. One injection operation will allow to obtain with the envelope or the cover locking means (hooks 21) and attachment means (pins) 27) as well as the different openings (15, 18) and housing (22).

According to a variant of the invention, it will particularly advantageous to produce the envelope cylindrical 12 by winding a flat sheet.

Figure 8 shows such a flat sheet 29 which carries the rectangular openings 15 delimited by strands 14a and 14b. The sheet 29 also bears on an upper edge 29a a row of pins 27 and on a lower edge 29b a row of housings 22.

The flat sheet 29 also bears on one of its edges lateral 29c at least two tabs 30 (here five tongues).

These tabs are intended to cooperate with lights 31 carried by another lateral edge 29d of the sheet, so as to allow these edges to be joined lateral and thus the constitution of the cylindrical envelope 12 of the housing (such an envelope thus being easily removable and reassemblable).

The lights here affect the shape of slits rectangular having substantially the same dimensions as the tabs and arranged in projecting windows on the lateral edge 29d.

The axis 16 of the envelope obtained is shown as indicative in figure 8 to remind the direction winding. This axis 16 is parallel to the lengths of the rectangular openings 15.

Figures 10a and 10b show the implementation phases place tabs 30 in the lights 31. The profile of tabs is chosen such that after its introduction into the corresponding light 31 there is an abutment of a ledge 32 of the tab on one side of the light and therefore locking.

Such a variant makes it easier to inject the cylindrical casing of the case by simplifying tooling, therefore reducing manufacturing costs. In reducing the size of the cylindrical envelope, it also makes it easier to store and transport components of the case before assembling the ammunition.

Figures 7a and 7b show a second mode of realization of a housing according to the invention.

These figures also make it possible to highlight the use of a case according to the invention with ammunition in which the tail 3a of the projectile 3 enters deep into the propellant charge and therefore sits in the vicinity of the upper end 8a of the door tube primer 8.

The cover 13 is in contact with the tail 3a and the plane which it defines therefore cuts the primer-carrying tube 8.

The axial opening 17 has a chosen diameter greater than that of the primer holder tube 8. The flexible radial strips 23 allow the introduction of the end of the leader tube 8 inside the housing 2.

Thanks to the axial opening 17 and the lamellae 23, the assembly and disassembly of. ammunition is easy to achieve without deterioration of the case and without flow of the load of powder it contains.

The embodiment according to Figures 7a and 7b differs also precedent by the presence, at an edge upper 2a of the housing, of cuvettes 33 regularly distributed angularly.

This embodiment is more particularly intended to a housing fixed to a connecting element 24 which is itself intended to be made integral by riveting a socket 5.

The connecting element then carries fixing holes 35 which are intended to receive rivets 36.

The rivets usually used in such fasteners have an axial needle, the insertion of which causes deformation of the rivet and the desired connection.

Figure 9 shows more precisely the detail identified by arrow D in FIG. 7a.

The bowls 33 have a frustoconical profile and are arranged so that they are after mounting of the housing 2 opposite the fixing holes 35 carried by the connecting element 24.

The bowls 33 make it possible to provide a housing in look of the rivet 36 which allows, during the assembly of the ammunition, placing the rivets without them being bothered by the presence of grains of powder filling the holes mounting 35.

Bowls also have the advantage of preventing possible ejection of the needle 37 from the rivet 36 in the propellant charge when the ammunition is subjected to vibration.

Such needle ejection could cause loss of the rivet 36 and the separation of the element of connection 24 and socket 5.

The bowls are obtained by injection with the sheet 29 intended to form the cylindrical envelope of the case.

To facilitate subsequent disassembly operations ammunition, we will preferably give to the bottom of the bowl 33 a wall thickness such that it allows its drilling by voluntary action on needle 37 for drive out of the rivet 36.

Various variants are possible without leaving of the scope of the invention.

It is thus in particular possible to define a housing the cylindrical envelope of which carries a trellis having a different mesh geometry, for example with diamond-shaped openings.

It is also possible to define a box 12 whose the cylindrical envelope is obtained directly by injection therefore without making a flat perforated sheet.

Claims (12)

1. A casing (2) for a propellant charge, notably for a piece of ammunition comprising a projectile (3) and a stub (5), said casing being integral with the projectile and comprising a substantially cylindrical envelope (12) and a closing cover (13), characterized in that the cylindrical envelope (12) is made of a plastic material and in that it is constituted by a lattice formed of strands (14a, 14b) marking out openings (15) coming through the envelope (12), the closing cover (13) being made of a plastic material and incorporating at least one opening.
2. A casing according to Claim 1, characterized in that the lattice is formed by the repetition of a rectangular elementary mesh whose width is less than the diameter or one of the grains of propellant powder intended to fill the casing (2).
3. A casing according to Claim 2, characterized in that the rectangle length of the elementary mesh is parallel to the axis (16) of the cylindrical envelope (12).
4. A casing according to one of Claims 1 to 3, characterized in that the cylindrical envelope (12) is obtained by rolling a plane sheet.
5. A casing according to Claim 4, characterized in that the plane sheet carries on one of its edges (29c) at least two tabs (30) intended to cooperate with at least two slots (31) carried by another edge (29d) of the sheet, so as to enable these edges to be made integral thereby constituting the cylindrical envelope (12) of the casing.
6. A casing according to one of Claims 1 to 5, characterized in that it incorporates means (27) enabling it to be hooked onto a linking element (24) integral with a projectile (3).
7. A casing according to Claim 6, characterized in that the hooking means are formed by barbs (27) intended to penetrate into openings (28) made in the linking element (24).
8. A casing according to one of Claims 1 to 7, characterized in that the cover (13) incorporates several openings in the shape of slots (18) marked out by arcs of a circle (19a, 19b) whose axis is the axis (16) of the casing, said slots evenly spaced angularly.
9. A casing according to Claim 8, characterized in that the cover (13) incorporates an axial circular opening (17) having at least three flexible radial strips (23).
10. A casing according to one of Claim 8 or 9, characterized in that it has an outer cylindrical rim (20) intended to cooperate with the cylindrical envelope (12) of the casing.
11. A casing according to Claim 10, characterized in that the rim (20) incorporates at least three hooks (21) evenly spaced angularly and intended to cooperate with housings (22) in the cylindrical envelope (12) of the casing to lock the cover (13) onto the envelope (12).
12. A casing according to one of Claims 1 to 11 and intended to be made integral with a linking element (24) which is itself integral with the projectile (3) and intended to be fastened to a stub (5) by riveting, characterized in that the cylindrical envelope (12) carries cups (33) evenly spaced angularly and intended to lie opposite the riveting fastening holes (35) made in the linking element (24).

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