EP1586852A1 - Caseless ammuniton and manufacturing method of such an ammunition - Google Patents

Abstract

The invention relates to an ammunition (1) comprising a projectile (2), a propellant charge (3) and an ignition device (4) of the latter which is integral with a sealing cap (5). This munition is characterized in that the propellant charge (3) comprises at least one block (7) of agglomerated charge which is covered with a protective sheath (17), the munition comprising a connecting piece (9) integral with the projectile (2) and surrounding at least a portion of a block (7) agglomerated filler, hooking means (18,22) being provided for binding the connecting piece (9) and / or the base (5) with at least one propellant block (7a, 7c). <IMAGE>

Description

The technical field of the invention is that of ammunition and more particularly ammunition wholesale caliber (greater than or equal to 50mm).

These ammunition are intended to be fired from a armored combat vehicle.

In order to facilitate the implementation of these ammunition, it is is known to provide them with a metal case or fuel. These are most often formed of a cardboard tube impregnated with nitrocellulose.

Thus the mass of the case is reduced. After shooting the case disappears and does not clutter the turret of the vehicle.

Fireproofness is ensured by means of a base metallic called shutter pellet. This pellet carries a tube igniter and it is the only part of the ammunition that is ejected from the room after firing to be stored in a base bag arranged in the turret.

Patent FR 2622687 describes by way of example such known ammunition.

The known fuel cases are manufactured according to paper techniques. They are expensive to obtain and have a Thickness greater than a millimeter that reduces the volume available for the propellant charge.

In addition these cases are highly mechanically stressed since they contain the propellant charge (mass of the order of 8 to 9 kg) and carry the projectile (mass of 7 to 15 kg) at one end while holding the base shutter at their other end (mass of the order of 3 kg). These cases suffer during drop tests. The case can be break, thus letting part of the load escape propulsion.

It is the object of the invention to propose an ammunition not having such disadvantages.

Thus the ammunition according to the invention makes it possible to increase, with a reduced cost, the volume of the propellant load without reduce the mechanical strength of the munition.

The subject of the invention is therefore an ammunition comprising a projectile, a propelling charge and a device ignition of the latter which is integral with a base

Thus the ammunition according to the invention makes it possible to increase, with a reduced cost, the volume of the propellant load without reduce the mechanical strength of the munition.

The subject of the invention is therefore an ammunition comprising a projectile, a propelling charge and a device ignition of the latter which is integral with a base sealing, ammunition characterized in that the loading propellant comprises at least one agglomerated charge block which is covered with a protective sheath, the ammunition comprising a connecting piece secured to the projectile and surrounding at least a portion of an agglomerated charge block, fastening means being provided for binding the piece of binding and / or the pellet with at least one propellant block.

The connecting piece may comprise a first means latching cooperating with a complementary profile of a front part of a block to ensure the solidarity of the projectile and loading, the first means of attachment the connecting piece then being constituted by nozzles regularly distributed angularly, the complementary profile of the front part of the block being formed by a throat.

According to another characteristic, the ammunition can have a bowl on the back of a block of agglomerated filler, bowl made integral with the block by a second hooking means cooperating with a profile complementary to the rear part of the block, bowl bound by elsewhere on the base by a fixing means.

The second attachment means of the bowl may be constituted by tongues springs regularly distributed angularly, tongues cooperating with a groove of the back part of the block.

The means for fixing the base to the bowl may include at least one spring washer surrounding a axial extension of the base.

The munition may include at least one axial wedge compressible interposed between an agglomerated charge block and the bowl and / or the projectile.

The protective sheath will advantageously cover the bottom grooves for fastening the connecting piece and / or bowl.

The protective sheath will preferably be a sheath made of a composite material combining at least one reinforcement and a binder.

At least one agglomerated block of charge may comprise on one of its faces a hollow cooperating with a surface bulging of a neighboring block to limit movement crosswise from one block to the other.

Each block may also include a surface flat annular, surrounding a hollow or a surface curved, complementary to a hollow of a neighboring block, the flat annular surfaces of two adjacent blocks being separated by a game.

According to one variant, each block may comprise on its outer surface of the longitudinal notches.

The propelling charge may include a rear block having an internal dwelling inside which will be arranged a propellant charge.

• on entoure un bloc de charge propulsive agglomérée ou un empilement de blocs avec une gaine de protection,
• on rend solidaire la gaine de protection avec le ou les blocs,
• on fixe une pièce de liaison au niveau d'une partie arrière d'un projectile,
• on fixe une cuvette à un culot obturateur,
• on rend solidaire le projectile et sa pièce de liaison d'avec le chargement en engageant la pièce de liaison sur une partie avant du ou des blocs,
• on rend solidaire le culot obturateur et sa cuvette d'avec le chargement en engageant la cuvette sur une partie arrière du ou des blocs.

The invention also relates to a method of mounting such an ammunition, characterized by the following sequence of steps:

• a block of agglomerated propellant charge or a stack of blocks is surrounded with a protective sheath,
• the protective sheath is made integral with the block or blocks,
• attaching a connecting piece at a rear portion of a projectile,
• a bowl is fixed to a shutter pellet,
• the projectile and its connecting piece are secured to the load by engaging the connecting piece on a front part of the block or blocks,
• the obturator base and its bowl are made integral with the load by engaging the bowl on a rear part of the block or blocks.

Advantageously, a preform will first be made of the protective sheath on tooling having the shape external propulsive loading then we will make this preform solidary of stacking blocks.

• la figure 1 est une vue en coupe longitudinale d'une munition selon un mode de réalisation de l'invention,
• les figures 2 et 3 sont des vues agrandies des moyens de liaison d'un bloc propulsif avec la pièce de liaison avant et la cuvette arrière respectivement,
• la figure 4 est une vue de détail de la jonction entre deux blocs propulsifs,
• la figure 5 est une vue en coupe transversale d'une variante de réalisation de l'invention.

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

• FIG. 1 is a longitudinal sectional view of a munition according to one embodiment of the invention,
• Figures 2 and 3 are enlarged views of the connecting means of a propulsion unit with the front connecting piece and the rear bowl respectively,
• FIG. 4 is a detailed view of the junction between two propulsion units,
• Figure 5 is a cross-sectional view of an alternative embodiment of the invention.

Referring to FIG. 1, a munition 1 according to a particular embodiment of the invention comprises a projectile 2 (of which only the rear part is visible), a propellant charge 3 and an ignition device 4 of this propulsive loading.

The projectile could of course be a projectile under calibrated (having a bar integral with a shoe) or well an explosive projectile with caliber. The structure of projectile itself is not the subject of this invention and therefore it is not necessary to describe it more in detail.

The ignition device 4 is secured to a base 5 which in a known manner has a body solid metal bearing a sealing lip in rubber 6. Such a cap is described by the patent US4159678.

According to the invention the propellant charge 3 of the ammunition comprises at least one agglomerated charge block 7, here three blocks 7a, 7b and 7c stacked.

The blocks 7a, 7b and 7c of agglomerated charge are conventionally constituted by a propellant powder formed of grains agglomerated by a binder. Such blocks are described for example by the patents US3092525, US5516378 and FR2776656.

The blocks are made in molds having shapes appropriate. Each block 7 has an internal bore 12a, 12b, 12c for facilitating the lighting of the blocks from the ignition device 4.

The front block 7a also has an external profile before conical 8 which is housed inside a room of plastic link 9 fixed in a groove device 10 of the projectile 2 (such a connecting piece is described in the patent FR2801667).

The front block 7a also has a cylindrical surface 11 on which is positioned a cylindrical surface 9a of the connecting piece 9. A wedge 29 of compressible material (by example in expanded polystyrene) is interposed between the face upper block 7a and the projectile 2.

The rear block 7c has a curved rear profile which is lodged in the base 5.

The rear block 7c also has a cavity 13 allowing the development of the flame generated by the ignition device 4. This cavity 13 may contain a charge of granular propellant powder (not shown) which will facilitate the ignition of the rear block 7c.

In order to avoid relative transverse movements of blocks in relation to each other, blocks 7b and 7c each have a hollow 14 cooperating with a surface complementary bulge carried by the neighboring block (see also Figure 4). Moreover each block 7 comprises at least a planar annular surface 15a or 15b which is arranged around the hollow 14 or the complementary convex surface of the hollow. The annular surfaces 15a and 15b of two blocks consecutive games are separated by a game 16 of the order of millimeter. Thus the blocks 7 are in contact only at the level of the hollow 14.

Such an arrangement makes it easier to relative positioning of a block compared to others because it gives some ability to pivot a block by relation to the other at the level of the hollow 14.

According to the invention blocks 7a, 7b and 7c have their outer cylindrical surface surrounded by a sheath of protection 17. This protective sheath 17 covers also partially the convex rear part of the block 7c and it is thus interposed between the base 5 and the rear block 7c.

The sheath 17 will be made of a composite material combining a reinforcement (such as glass fibers, carbon, cotton or linen) and a binder such as a resin epoxy or phenolic.

As will be described later, this sheath is preformed on an appropriate tool before being applied around the blocks. We could also wrap a fabric of fibers around the blocks then place the set in a mold allowing the injection and the cooking of the resin which would then ensure the joining of the propulsion blocks and fibers.

The establishment of a sheath 17 fixed around the blocks makes it possible to ensure the mechanical strength of the stack of blocks 7.

The sheath 17 serves to ensure the protection of Agglomerated charge blocks 7 against moisture and shocks.

This sheath does not fulfill the same function as that a fuel bushing according to the prior art. She does not itself ensure the mechanical maintenance of the propellant loading compared to the projectile but only the cohesion of the stack of blocks.

The thickness of the sheath is of the order of 0.3 mm which is less than the thickness of a conventional fuel holster (about 3 mm). This results in an increase in the mass of propulsive loading of almost 10% compared to a agglomerated loading incorporated into a combustible case classic (11 kg instead of 10 kg for a 120mm caliber) and 30% compared to a grain propellant charge (8.3 kg).

According to the invention the mechanical connection of the propellant charge 3 and the projectile 2 is ensured thanks to the connecting piece 9 integral with the projectile 2. This link is more particularly visible in FIG.

This connecting piece thus comprises a first means fastening constituted by spouts 18 regularly distributed angularly. These beaks are secured to a crown thin cylindrical 9b of the connecting piece 9. They cooperate with a complementary profile carried out at the level of the party before block 7a, complementary profile which is constituted here 19. The spouts 18 have a front portion 18a conical which cooperates during assembly with the conical profile before 8 of the block 7a so as to widen by deformation resilient crown 9b, thus allowing the mounting of the connecting piece 9 carrying the projectile 2 on the front block 7a.

During assembly the spouts enter the groove 19 and they thus ensure the joining of the connecting piece 9 and the front block 7a. The rear face 18b of the nozzles being then facing a flat stop surface of the groove. By elsewhere the wedging is ensured by the compression of the hold 29 between the projectile 2 and the front block 7a.

The sheath 17 covers the bottom of the throat 19 and is therefore compressed by the nozzles 18 during assembly. We provide thus the sealing of the blocks with respect to external moisture.

Figure 3 shows how the link is achieved mechanical between the base 5 and the rear propulsion unit 7c.

According to the invention, the ammunition comprises a bowl 20 made of a plastic material, bowl capping a rear portion 21 of the agglomerated charge block back 7c.

This bowl 20 is secured to the block 7c by a second means of attachment which consists of spring tabs 22 regularly distributed angularly. Here only one tab is visible. These tabs are made of sheet steel with spring and are attached to the bowl 20 by rivets 23.

The tongues 22 cooperate with a groove 24 arranged in the rear part of the propulsion unit 7c.

The tabs are oriented so that it is possible to slide the bowl 20 on the back of the block propulsion 7c, the tabs fold back by sliding on the back part 21. They resume their unfolded position the inside of the throat 24. They are then in contact with a stop plane 24a of the throat which prohibits the extraction of the bowl 20.

As for the front groove 19, the sheath 17 covers the bottom of the throat 24.

The bowl 20 is also linked to the base 5 by a fastening means which comprises a holding washer 25 surrounding an axial extension 26 of the base 5.

The washer will be for example an elastic washer split (more commonly known as Circlips).

To avoid damaging the propellant charge block rear 7c, a washer 27 is interposed between the bowl 20 and block 7c. This washer 27 provides an axial wedging compressible which also ensures the contact of ends of the tongues 22 with the abutment plane 24a. She will be made for example of expanded polystyrene or elastomer and it will be glued to the bowl 20.

The connection between the base 5 and the load block 7c has some angular flexibility which is ensured by the tabs 22.

The assembly of this ammunition is done in the way next :

We first realize an assembly of different agglomerated propellant charge units 7a, 7b and 7c in the stacking and then surrounding them with a protective sheath 17.

For this purpose, a preform is produced by pre-stratification of the sheath 17 on a tool having the shape of the load definitive propulsion system and in particular to train the subsequent profile of the sheath at the grooves 19 and 24. This preform will be opened longitudinally to facilitate its subsequent installation on the loading blocks.

The preform is then placed around the blocks previously impregnated on the surface with an epoxy resin or Phenolic. We will place notched tooling rings at level of throats 19 and 24, rings that will be immobilized by appropriate means. We will then place the set in a flexible and waterproof case to empty around of the outer surface of the sheath 17. The internal pressure will be of the order of 0.5 atmosphere.

This depression allows to marry the profile external propulsion blocks by the profile of the sheath 17 during the polymerization of the resin providing the bond mechanical. We can accelerate the polymerization process of the resin by putting in an oven the whole (temperature from 30 ° C to 40 ° C) for about one hour.

This process increases the mechanical strength propulsive loading and especially rigidity at the level notch grooves 19 and 24.

Moreover, the connecting piece 9 is fixed at the level of the groove 10 of the projectile 2 and a bowl 20 is fixed to a shutter base 5.

We then make the loading of the projectile and of the connecting piece 9 by engaging the latter on a front portion of the block 7a to the entrance of the nozzles 18 in the front groove 19. When setting up compress the wedge of polystyrene loading 29 between the top of block 7a and the projectile.

It is possible to place a booster charge in grains at inside the cavity 13.

The loading is made integral with the shutter 5 and its bowl 20 by engaging the bowl on the rear part 21 of the block 7c to the input of the spring tabs 22 in the back throat 24.

Finally, it is possible to position the igniter 4 on the base 5.

We see that the invention makes it possible to produce an ammunition having an increased propulsive loading mass without the mechanical strength is diminished. Moreover the cost of the connecting sheath 17 is very small and much less than that of a combustible case.

The sheath is destroyed during firing and ejected with the gases propulsion.

FIG. 5 shows in section an ammunition according to a variant embodiment of the invention. This ammunition differs from the previous one in that each block 7 has on its external cylindrical surface of the longitudinal notches 28. These notches have a reduced depth (of the order of millimeter). They are regularly distributed angularly and extend longitudinally the entire length of a block. Here again the sheath 17 surrounds the block and she applies on this one also inside the notches 28.

The blocks 7 are oriented during assembly so that that the notches 28 are arranged in the extension the each other.

This produces an ammunition whose external surface has notches that extend over substantially any the length of the propelling charge and which constitute chimneys allowing passage of propellant gases between the chamber of the weapon and the propellant blocks. thus the fragmentation of the sheath 17 during firing as well as his evacuation out of the weapon.

The notches can of course be in number and / or different distribution, as well as having shapes and / or different dimensions.

As a variant it is of course possible to make ammunition with means of lighting blocks having a different structure.

We will thus be able to implement ignition transmission extending longitudinally to through the blocks 7 and from the ignition device 4.

We will then of course plan for holes through blocks allowing passage of said cords.

Cords may be formed by cords ITLX pyrotechnics of the type described in the applications US4917017 or US5179250.

These cords can also be simply constituted by inert diffuser tubes made of flexible plastic to drive the flame produced by the ignition charge. Such diffuser tubes are described by the patent application FR01 / 09053.

The ignition transmission lines will be introduced, before fixing the base, in holes made in the different propellant blocks 7. These holes will be well sure oriented angularly to each other when mounting the load to ensure alignment of holes.

Cords will distribute evenly the ignition of the different blocks from the device ignition 4.

The ignition device may also include a plasma igniter of the type described by the patents FR2807610 or FR2807611.

Claims (14)

Ammunition (1) comprising a projectile (2), a propellant charge (3) and an ignition device (4) thereof which is integral with a sealing cap (5), ammunition characterized in that the loading propellant (3) comprises at least one block (7a, 7b, 7c) of agglomerated filler which is covered with a protective sheath (17), the munition comprising a connecting piece (9) integral with the projectile (2) and surrounding at least a portion of a block (7a) of agglomerated filler, hooking means (18,22) being provided for binding the connecting piece (9) and / or the base (5) with at least one propulsion block (7a, 7c). Ammunition according to claim 1, characterized in that the connecting piece comprises a first hooking means (18) cooperating with a complementary profile (19) of a front portion of a block (7a) to ensure the fastening of the projectile (2) and the load (3), the first attachment means of the connecting piece being constituted by spouts (18) regularly distributed angularly, the complementary profile of the front portion of the block being formed by a groove (19). . Ammunition according to one of claims 1 or 2, characterized in that it comprises a bowl (20) capping a rear portion (21) of a block (7c) of agglomerated filler, bowl made integral with the block by a second means of hooking (22) cooperating with a complementary profile (24) of the rear part of the block (7c), cuvette also linked to the base (5) by a fixing means (25). Ammunition according to claim 3, characterized in that the second attachment means of the bowl is constituted by spring tongues (22) regularly distributed angularly, tongues cooperating with a groove (24) of the rear portion of the block (7c). Ammunition according to one of claims 3 or 4, characterized in that the means for fixing the base to the bowl comprises at least one spring washer (25) surrounding an axial extension (26) of the base (5). Ammunition according to one of claims 3 to 5, characterized in that it comprises at least one compressible axial wedging (27,29) interposed between an agglomerated filler block and the bowl (20) and / or the projectile (2). Ammunition according to one of claims 1 to 6, characterized in that the protective sheath (17) covers the bottom of the grooves (19,24) allowing attachment of the connecting piece (9) and / or the bowl (20). ). Ammunition according to one of claims 1 to 7, characterized in that the protective sheath (17) is a sheath made of a composite material combining at least one reinforcement and a binder. Ammunition according to one of claims 1 to 8, characterized in that at least one block (7) of agglomerated charge has on one of its faces a recess (14) cooperating with a curved surface of a neighboring block to limit transverse displacements from one block to the other. Ammunition according to claim 9, characterized in that each block comprises a planar annular surface (15a, 15b), surrounding a recess (14) or a convex surface complementary to a recess of a neighboring block, the plane annular surfaces of two adjacent blocks being separated by a clearance (16). Ammunition according to one of claims 1 to 10, characterized in that each block (7) has on its outer surface longitudinal notches (28). Ammunition according to one of claims 1 to 11, characterized in that the propellant charge comprises a rear block (7c) having an inner housing (13) inside which is disposed a propellant charge. A method of assembling a munition according to one of claims 1 to 12, characterized by the succession of the following steps: a block (7) of agglomerated propellant charge or a stack of blocks (7a, 7b, 7c) is surrounded by a protective sheath (17), the protective sheath (17) is made integral with the block or blocks (7), a connecting piece (9) is fixed at a rear part of a projectile (2), a bowl (20) is fixed to a shutter base (5), the projectile (2) and its connecting piece (9) are made integral with the load by engaging the connecting piece (9) on a front part of the block or blocks, the shutter base (5) and its bowl (20) are made integral with the load by engaging the bowl on a rear part of the block or blocks. A method of assembling a munition according to claim 13, characterized in that a preform of the protective sheath (17) is first produced on a tooling having the external shape of the propellant charge and then this preform is made integral with stacking blocks.

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