EP0401114B1 - Holding device for a projectile in relation to a telescoped ammunition case - Google Patents

Description

The present invention relates to a device for holding a projectile relative to the casing of a telescoped type of munition.

Telescoped ammunition, which has been the subject of numerous developments in recent years, is characterized by the fact that the projectile is located inside the casing containing the propellant charge instead of being projecting relatively to the latter.

The main advantage of such an arrangement is that it allows, for equal ballistic performances, to define shorter munitions which allows the design of more compact weapons or at higher rates of fire.

However, the development of such ammunition faces a number of problems.

Thus the projectile is no longer in position in the barrel of the weapon when the ammunition is placed in the chamber, it is the pressure due to the combustion of the gases of the propellant charge which will initially bring the projectile to post, then push it inside the tube.

In order to keep the same ballistic performances as those of a conventional ammunition, it is necessary to fill the cartridge case of the ammunition with the greatest possible quantity of propellant powder, which imposes the presence of an annular layer of this powder around the projectile.

When firing there is a risk that the combustion gases will get ahead of the projectile before it has penetrated the tube enough to be able to seal.

Various solutions have been envisaged to avoid such a phenomenon, let us cite for memory the patent US4604954 which describes an ammunition in which a first charge of propellant powder, contained in a small cylinder, acts only on the projectile by means of a sliding piston in this cylinder, the main charge surrounding the projectile is only lit when the latter has entered the barrel of the weapon.

Such ammunition is complex because it requires the assembly of several fine mechanical parts, moreover the transition between the combustion of the first charge and that of the second charge is difficult to control, which risks reducing the efficiency of the charge. therefore propellant ammunition performance.

Patent US4770098 proposes an ammunition in which a ring comes to close the front part of the sleeve, this plastic ring has a bore whose diameter is slightly smaller than that of the projectile.

It is therefore immobilized by the ring which thus seals the combustion gases of the propellant charge.

The ring also makes it possible to position the projectile relative to the casing therefore also relative to the barrel of the weapon, a certain number of holes make it possible to play on the stiffness of the ring and thus on the minimum pressure necessary for setting in motion of the projectile .

Such a concept of ammunition is particularly interesting because it makes it possible to produce ammunition of the telescoped type with a single propellant charge.

However, the ring is not sufficient to hold the projectile and this is how radial ribs are provided on the internal surface of the sleeve, the function of which is to support the projectile by its rear part.

These ribs reduce the volume available for the powder and risk disturbing the regularity of the ignition.

It would be tempting to remove the ribs but this would then require providing a ring having a large contact surface with the projectile, which cannot be accepted because a ring of too long length would reduce the volume available for the powder.

Patent GB1310607 shows a telescoped munition comprising a combustible or fragmentable casing comprising radial ribs ensuring the support of the projectile, as well as a plug ensuring sealing and allowing the projectile to be held axially relative to the casing.

This arrangement has the same drawbacks as that of patent US4770098, the ribs provide radial support and limit the volume available for the propellant charge.

US Pat. No. 3,575,112 describes a telescoped munition comprising several molded propellant charge elements.

The projectile is placed in a bore of this solid charge and is held radially by it, a washer ensures the axial positioning of the projectile and is bonded to the propellant charge.

The washer is not secured to the projectile, which implies that in the event of a fracture of the propellant blocks, following mechanical stresses of placing in position, the projectile will no longer be held radially.

This is all the more annoying that this munition does not have an envelope containing the propellant charge and that the washer is stuck on the charge itself which risks fracturing.

Patent US4015527 shows an ammunition also comprising several molded propellant charge blocks arranged in a combustible envelope which is not closed by a ring.

It is the object of the invention to provide a device for holding a projectile relative to the casing of a telescoped type of munition which does not have such drawbacks.

Thus, the subject of the invention is a device for holding a projectile relative to the casing of a telescoped type of ammunition, comprising at least one annular ring fitted to the casing and in which the projectile is disposed, and a cap. fitted inside the ring, holding device characterized in that the cap is integral with the projectile at the front part of the latter.

In the case where the projectile is of the sub-calibrated type, stabilized by empennage, and placed inside a shoe with caliber, the cap may be integral with the shoe.

In the case where the projectile is of the gyro-stabilized type and comprises a ballistic warhead, the cap may be made integral with the projectile at the level of the ballistic warhead.

The holding device according to the invention may also include means ensuring the support of the projectile on the envelope at its rear part.

According to a particular embodiment, these support means comprise a wedge secured to the projectile at its rear part.

According to another embodiment, the means ensuring the support of the projectile comprise at least three tabs, integral with the ring at its rear part, regularly spaced from one another and extending in an axial direction.

According to a variant, the envelope has at least one bulge at its internal surface and the wedge comes to bear on this bulge.

The wedge will preferably include at least three arms regularly spaced from each other, it may be integral with the shoe or the tail.

The invention will be better understood on reading the description which follows of particular embodiments, description made with reference to the appended drawings in which:

Figure 1 is an axial sectional representation of a telescoped munition according to the prior art.

Figures 2 to 8 show different telescoped munitions integrating different embodiments of the holding means according to the invention.

Figure 2A is a front view of the cap.

Figure 3A shows the ammunition of Figure 3 after firing of the propellant charge, when the projectile is about to leave the envelope.

Figure 3B shows a detail of Figure 3.

Figure 4A is a section along the plane A-A of Figure 4.

Figure 5A is a section along the plane BB of Figure 5.

Figure 7A is a section along the plane C-C of Figure 7.

Figure 8A is a front view of the sole block which is used in the variant of Figure 8.

Referring to FIG. 1, a telescoped munition 1 of the type described in patent US4770098 comprises a casing 2, preferably made of plastic material, and closed at a rear end by a base 5, also made of plastic material, which carries an ignition device 6 of known type.

The envelope contains a propellant charge 7, it is closed at its front end by an annular ring 3 also made of plastic.

The ring 2 is thus a means for holding the projectile relative to the envelope, therefore relative to the weapon. As such, it therefore ensures correct positioning of the projectile opposite the barrel of the weapon (not shown).

A projectile 4, which is here of the gyrostabilized type, is placed in a housing 9, cylindrical or slightly conical, of the ring 3.

The adjustment of the projectile and the ring is of the tight type, the sealing belt 8 has a diameter greater than that of the cylindrical housing, and thus achieves a localized deformation of the ring.

Such an adjustment makes it possible to ensure that the setting in motion of the projectile does not intervene until a certain level of pressure is reached inside the envelope.

Figure 2 shows a telescoped munition integrating a first embodiment of the holding means according to the invention.

The length of the ring 3 has been reduced, which has made it possible to increase the mass of propellant charge.

The rear face of the ring, which is in contact with the load, thus arrives substantially at the level of the conical front part of the projectile.

The projectile 4 carries at its front part a cap 10, which has an internal profile corresponding to the external profiles of the ballistic warhead 11 and of the external surface 12 of the front part of the projectile.

The cap 10 is made integral with the projectile by bonding, it comprises an internal crown 10a and an external crown 10b connected by radial partitions 10c and by a conical partition 10d (see Figure 2A), the cap is exploded at the outlet of the tube of the weapon under the effect of centrifugal force.

The cap 10 is adjusted tightly in the cylindrical housing 9 of the ring 3, this so as to ensure the initial confinement of the propellant charge as well as the gas tightness before the forcing of the belt 8 inside the cylindrical housing 9 .

Such a configuration made it possible to maintain the projectile with a ring of reduced dimensions, and therefore with a maximum propellant charge mass, while retaining a socket with a cylindrical internal profile.

To avoid at the time of firing the disadvantages possibly due to waves of transverse pressures which would risk causing a slight tilting of the projectile and a bad setting in the barrel of the weapon, the ring 3 will preferably have a length as it is in contact with at least 50% of the external surface of the cap.

Figure 3 shows another embodiment of the holding means according to the invention.

Here we sought to further increase the mass of propellant charge contained in the envelope, so the front ring has the minimum length compatible with its resistance to pressure.

The holding means here comprises, in addition to the ring 3 and the cap 10, a shim 13 made of plastic secured to the projectile 4 at its rear part.

This wedge has three arms 13a, 13b, 13c regularly spaced (see Figure 3B) which are formed by the juxtaposition of three identical arcs.

The wedge could also be in one piece.

The end of the arms bears on the internal cylindrical surface of the casing 2.

In this particular embodiment, the wedge 13 completes the front cover, the contact surface with the ring is insufficient to avoid possible tilting of the projectile. The wedge / cap / ring assembly constitutes the means for holding the projectile relative to the shell of the ammunition.

Figure 3A shows the projectile when it leaves the envelope, it is then in the barrel of the weapon 21 shown schematically. The wedge 13 is stopped then broken by the ring 3, it is ejected from the envelope after the projectile without disturbing the trajectory thereof or the operation of the weapon.

Figure 4 shows another embodiment of the invention, in which the ring 3 has at its rear part three legs 14 regularly spaced (see Figure 4A). The projectile is then supported at its front part by the cap 10, and at its rear part by the lugs 14 of the ring 3.

It is possible to reduce the length of the cylindrical part of the ring to its minimum admissible value, which makes it possible to increase the mass of propellant charge contained in the envelope, the support of the rear part of the projectile being provided by the legs of the ring, this avoids mounting a shim on the projectile.

Figure 5 shows another variant of the invention in which the casing 2 of the ammunition carries three bulges 19 regularly distributed, the projectile is then still supported at its front part by the cap 10, and at its part rear by the bulges 19 of the casing 2 (see Figure 5A).

FIGS. 6 to 8 show other embodiments of the holding means according to the invention intended for a telescoped munition in which the projectile 4 is of the sub-calibrated type stabilized by a stabilizer 17, and comprises a sub-projectile 16, integral with a shoe 15, consisting of several elements (in general three), a known sealing means not shown, for example a silicone coating, ensures gas tightness at the separations between the elements of the shoe.

Referring to Figure 6, the cap 10 is integral with the shoe 15 at a circular groove 18 thereof.

The cap provides sealing against propellant gases inside the barrel of the weapon and thus plays the role of belt.

In this particular embodiment, the cap 10 made of plastic, is injected onto the aluminum alloy shoe already equipped with the sub-projectile 16.

In order to avoid at the time of firing the inconveniences possibly due to waves of transverse pressures which would risk causing a slight tilting of the projectile and a bad setting in the barrel of the weapon, the ring 3 will preferably have a length such that it is in contact with at least 50% of the external surface of the cap.

If it is desired to reduce the dimensions of the ring, it will be necessary to provide a spacer at the rear part of the projectile as has already been described previously.

The aerodynamic forces which will be exerted on the hoof and the cap at the exit of the barrel of the weapon will cause the rupture of the cap and the release of the sub-projectile.

The projectile shown in Figure 6 has a shoe of the pusher type, in order to gain even more volume for the propellant charge it is possible to design an ammunition in which the shoe is of the "tractor" type, that is to say as the resultant of the forces exerted on the shoe by the propellant gases has a point of application well in front of the center of gravity of the sub-projectile.

However, projectiles driven by a tractor shoe are very sensitive to transverse pressure waves and in this case it will be essential to provide a wedging means at the rear part of the projectile so as to prevent it from tilting, regardless of the length of the projectile. relative contact between the ring and the cap.

Thus in FIG. 7, an annular block 13 made of plastic material and comprising three regularly spaced arms 13a, 13b, 13c is made integral with the shoe at the rear part of the latter, (see FIG. 7a). The shoe carries for this purpose three extensions 20 on which the shim 13 adjusts. The connection between the shoe and the shim will be made by threading, gluing or tight adjustment.

The wedge will be broken when the extensions pass inside the ring, the wedge will then be ejected following the shoe and will not disturb the trajectory of the sub-projectile.

The extensions 20 will guide the projectile inside the barrel of the weapon.

In Figure 8 the wedge 13 is made integral with the projectile at the tail.

The fit is of the tight type and the annular part of the shim 13 therefore has here a conical internal profile 22 on which the external edges of the fins of the tail unit 17 come to bear.

The wedge has, as in the previous variant, three regularly spaced arms 13a, 13b, 13c (see Figure 8A), the guidance is thus ensured without the need to reduce the volume of the propellant charge.

The mounting of the wedge on the tail will be carried out by passing the sub-projectile inside the latter and thereby achieving a deformation of the wedge by the fins.

The wedge will be further broken during the passage inside the ring and it will be ejected following the shoe, without disturbing the trajectory of the sub-projectile.

Finally, it should be noted that the manufacture and loading of these different munitions is particularly easy, it suffices to provide a base 5, metallic or not, which is distinct from the casing 2.

Thus the projectile, carrying cap and ring and possibly one or more shims is first made integral with the envelope, then the propellant charge is introduced from the rear of the envelope, the base being put in place last. .

Claims (10)

1. A holding device for a projectile (4) in relation to a casing (2) of a telescoped ammunition (1), said projectile (4) being confined in a cartridge casing, comprising at least one annular sleeve (3) fitted to said casing (2) and in which said projectile (4) is located, and a nose fairing (10) fitted inside the sleeve (3), wherein said nose fairing is integral with said projectile (4) and is located at the fore conical section of said projectile.
2. A holding device as in claim 1 more particularly intended for an ammunition in which the projectile (4) is of the subcaliber type and includes a sub-projectile (16) stabilised by fins (17) and placed inside a sabot (15) to caliber, wherein the nose fairing (10) is integral with the sabot.
3. A holding device as in Claim 1 and more particularly intended for an ammunition in which said projectile (4) is of the spin-stabilized type and comprises a ballistic warhead (11), wherein said nose fairing (10) is made integral with said projectile (4) near said ballistic warhead (11).
4. A holding device as in Claims 1 to 3, wherein it comprises also means (13, 14, 12) providing support for said projectile (4) on said casing (2) near its aft section.
5. A holding device as in Claim 4, wherein said supporting means include a wedge (13) integral with said projectile (4) near its aft section.
6. Holding device as in one of Claims 4 or 5, wherein the supporting means holding the projectile include at least three lugs (14) integral with the sleeve (3) at the location of its aft section, evenly spaced from one another and extending in an axial direction.
7. Holding device as in one of Claims 4 or 5, wherein the supporting means of the projectile comprise at least one bulge on the inner surface of the casing (2).
8. A holding device as in one of claims 5 to 7 wherein said wedge (13) includes at least three arms (13a, 13b, 13c) evenly spaced from one another.
9. Holding device as in Claims 2 and 8, wherein the wedge (13) is integral with the sabot (15).
10. Holding device as in Claims 2 and 8, wherein the wedge (13) is integral with the fins (17).

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