EP0401115B1 - Holding device for a projectile in relation to a telescoped ammunition case - Google Patents

Description

The present invention relates to a holding device relative to the casing of a munition of the telescoped type of a projectile of the sub-calibrated type stabilized by empennage.

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.

Generally the propellant charge surrounds the projectile and we are faced with gas tightness problems, in fact the projectile not being placed 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 station, then in a second time push it inside the tube.

During firing, it is therefore to be feared that the combustion gases will get ahead of the projectile before it has penetrated the tube enough to be able to seal.

Complex solutions have been developed, they generally provide for several propellant charges ignited successively, see for example the patent US4802415.

A simpler solution is proposed by patent US4770098 which describes an ammunition in which a ring closes the front part of the sleeve, this plastic ring has a bore whose diameter is slightly less than that of a caliber projectile.

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

However, such a concept will only be interesting if the dimensions of the ring do not excessively limit the volume reserved for the propellant charge.

To be able to apply it to a munition in which the projectile is of the under-calibrated type stabilized by empennage and placed inside a shoe, it is then essential to design a shoe of the "tractor" type, it is to say that the result 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 projectile.

Indeed, the "caliber" part of such a shoe will then be substantially at the level of the point of the projectile and can therefore be adjusted in the retaining ring.

However, projectiles driven by a tractor hoof are very sensitive to transverse pressure waves and it is essential to provide arms integral with the rear part of the hoof and ensuring guidance in the barrel of the weapon.

Such arms, of the caliber of the weapon, do not extend beyond the internal diameter of the retaining ring and cannot provide guidance inside the munition itself. However, if such guidance is optional in the case of conventional munitions for which the front part of the hoof is stationed in the barrel of the weapon, it becomes essential for a telescoped ammunition for which a good stationing is conditioned by the control of the trajectory of the projectile in the ammunition.

Patent EP0152492 describes a tractor sabot projectile in which the front part of the sabot projects outside the envelope and is intended to come into the barrel of the weapon. The front part of the projectile being in the barrel of the weapon as soon as the ammunition is placed, it is unnecessary to provide means for guiding the projectile relative to the envelope.

This patent does indeed show arms arranged at the rear part of the sabot and ensuring the guidance of the projectile in the barrel of the weapon, but these arms cannot ensure guidance relative to the casing of the ammunition in the case of ammunition whose envelope diameter is greater than the caliber of the weapon.

The patent US4015527 describes a telescoped ammunition of the type of that shown by the patent US4802415, that is to say comprising two different propellant charges.

The originality of the arrangement described is due to the presence of a shoe surrounding the tail of the sub-projectile and ensuring a sealing function inside the envelope of the ammunition. With such an arrangement, the shoe of the empennage is entrained in the barrel of the weapon and does not separate from the sub-projectile until it leaves the tube, which risks causing destabilization of the sub-projectile.

The patent US2971426 describes a loading method for a munition comprising a stabilized stabilizer projectile.

In a second phase of loading the projectile is positioned in a tool tube and a wedging washer comprising a cylindrical rim is placed at the level of the tail.

However after placing the projectile in the socket, the rim of the washer adopts a conical position which no longer ensures the slightest positioning of the projectile relative to the socket.

It is the object of the invention to propose means making it possible to obtain both guidance in the ammunition and in the barrel of the weapon while ensuring maximum volume for the propellant charge.

Thus, according to a first embodiment, the invention relates to a device for holding and guiding a projectile relative to the cylindrical casing of a munition of the telescoped type, projectile of the sub-calibrated type and comprising a sub -projectile placed inside a caliber sabot, sabot carrying at its rear part at least three arms regularly spaced angularly from one another and providing guidance inside a barrel of a weapon, the device is characterized in that it comprises on the one hand an annular ring adjusted to the envelope and in which is housed the front part of the projectile, and on the other hand a wedge secured to the projectile and ensuring its support and guidance on the internal surface of the envelope during its entire journey inside the latter, the shim dissociating from the projectile by coming into contact with the ring.

The wedge may preferably comprise an annular part carrying at least three radial extensions coming into contact with the internal surface of the envelope.

The wedge can advantageously be secured to the tail of the sub-projectile.

It may also be secured to the arms of the sub-projectile.

Preferably, the arms will extend to the front part of the hoof.

According to a second embodiment of the invention, the holding and guiding device comprises on the one hand an annular ring adjusted to the envelope and in which is housed the front part of the projectile, and on the other hand of the worn fingers by each arm, ensuring the support and guiding of the projectile on the internal surface of the envelope throughout its journey inside the latter, each finger passing during its contact with the ring from a deployed position in which it is supported on the internal surface of the envelope, in a retracted position in which the arms carrying the fingers provide guidance inside the barrel of the weapon.

According to a third embodiment of the invention, the holding and guiding device comprises on the one hand an annular ring adjusted to the envelope and in which is housed the front part of the projectile, and comprise at least three tabs, integral of the ring at its rear part, regularly spaced from each other in contact with the internal surface of the envelope and extending in an axial direction, legs on which the arms come to bear, and on the other hand a guide means preventing any relative rotation of the projectile and the envelope.

According to a fourth embodiment of the invention, the holding and guiding device comprises on the one hand an annular ring adjusted to the envelope, and on the other hand at least three swellings integral with the internal surface of the envelope , regularly spaced from each other and extending in an axial direction, bulges on which the arms come to bear, and in that they also comprise a guide means preventing any relative rotation of the projectile and the envelope.

According to variants, the guide means comprises on the one hand at least one plate, carried by a tab or a bulge, plate parallel to the axis of the ammunition, extending radially towards the interior thereof and axially over substantially the entire length of the tab or of the bulge, and on the other hand a slot provided on each arm, the plate being received in one of the slots.

The guide means may also include, on the one hand grooves, arranged on each leg or each bulge, silons parallel to the axis of the munition and extending over substantially the entire length of the leg or bulge, and d on the other hand at least one shearable pin carried by one of the arms and coming to circulate in one of the grooves.

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:

Figures 1 to 5 show different embodiments of the holding device according to the invention.

Figure 1A is a section of Figure 1 along the plane A-A.

Figure 2A is a front view of the sole block which is used in the variant of Figure 2.

Figure 3A is a section of Figure 3 along the plane B-B.

Figure 4A shows the ammunition of Figure 4 after firing of the propellant charge, when the projectile is about to leave the envelope.

Figure 4B is an enlarged view of the lock of Figure 4.

Figure 5A is a section of Figure 5 along the plane C-C.

Figures 6 and 6A show a preferred variant of the invention.

Referring to Figure 1, a telescoped munition 1 comprises a casing 2, preferably made of plastic, and closed at a rear end by a base 5, also made of plastic, 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 3 ensures correct positioning of the projectile opposite the barrel of the weapon (not shown).

A projectile 4, of the sub-calibrated type stabilized by a tail 10, comprises a sub-projectile 12, integral with a shoe 11, consisting of several elements (generally three) a known sealing means not shown, for example a silicone coating, ensures gas tightness at the separations between the elements of the shoe.

The front part of the shoe is placed in a cylindrical or slightly conical housing 9 of the ring 3.

The adjustment of the shoe and the ring is of the tight type, the shoe 11 carries, disposed in an annular groove 13 of the shoe, a belt 8 intended in known manner to achieve gas tightness in the barrel of the weapon.

The belt 8 has a diameter greater than that of the cylindrical housing, and thus achieves localized deformation of the ring.

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

In order to guide the projectile inside the barrel of the weapon, the sabot carries at its rear part three arms 14 regularly spaced angularly from one another.

These arms are made integral by a connection means of a support means on the internal surface of the envelope 2. This support means is constituted by a shim 15 made of plastic material which comprises an annular part 16 carrying at least three regularly spaced radial extensions 15a, 15b, 15c (see Figure 1a).

The connecting means here is a thread, but any other means would be possible, for example gluing or a tight fit.

The connection means will be broken when the arms pass inside the ring, the wedge will then be ejected following the shoe and will not disturb the trajectory of the sub-projectile. The arms will guide inside the barrel of the weapon.

On the munition of FIG. 2 the wedge 15 is made integral with the projectile at the level of the tail unit 10.

The fit is of the tight type and the annular part 16 of the shim 15 therefore has here a conical internal profile 28 on which the external edges of the fins of the tail unit 10 come to bear.

The wedge has, as in the previous variant, three regularly spaced arms 15a, 15b, 15c (see FIG. 2A), the guidance is thus ensured without the need to excessively 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.

On the munition of Figure 3, the casing 2 carries three bulges 17 regularly spaced from each other and extending in an axial direction. Each bulge carries a groove 18 parallel to the axis of the munition and extending over substantially the entire length of the bulge.

At least one of the arms 14 comprises a shearable lug 19 circulating in one of the grooves so as to provide guidance in translation and thus prevent any rotation of the projectile relative to the envelope.

The bulges constitute the support means of the arms, the thickness of the bulges is reduced (see FIG. 3A) which makes it possible not to reduce too much the volume reserved for the propellant charge, but to maintain contact between the ends of the arms and bulges, it is then necessary to provide a guide means which is constituted by the lug and the grooves.

A single lug is essential, but it will be convenient to provide as many grooves as bulges that in order to avoid projectile / envelope indexing which would complicate manufacturing.

The pins are dimensioned so as to be sheared at the time of their passage in the cylindrical housing 9 of the ring 3, they are ejected after the projectile so as not to disturb it and the functioning of the weapon.

Referring to Figure 4, the support means are constituted by fingers 20 carried by each arm 14 and can tilt in a radial plane around an axis integral with the arm.

A retaining lock 21 (which is here a pin, see Figure 4B) immobilizes the fingers in the deployed position which is shown in Figure 4. In this position, the outer end 22 of the fingers 20 comes to bear on the internal cylindrical surface of envelope 2.

When the projectile leaves the envelope, the fingers 20 strike the ring 3, which causes the shears of the locks 21, and the passage of the fingers to the retracted position shown in Figure 4A.

Figure 4A shows the projectile when it leaves the envelope, the fingers 20 are tilted relative to the shoe 11 and do not disturb the passage of the rear of the projectile when the latter enters the tube of the weapon schematically shown in 23.

The projectile then carries the finger with it into the barrel of the weapon, and the arms carrying the fingers can provide guidance inside the barrel.

Such an arrangement optionally makes it possible to increase the guide surface of the projectile inside the barrel of the weapon by giving the fingers a shape such that, in their retracted position, their heel 24 is located in the extension of the end arms 14 (see Figure 4B).

In the embodiment shown in Figure 5, the ring 3 has at its rear part three legs 25 regularly spaced, in contact with the inner surface of the envelope and extending in an axial direction.

At least one lug carries a rectangular metal plate 26, parallel to the axis of the ammunition, extending radially inwards of the latter and axially over substantially the entire length of the lug.

The plate or plates are put in place during the injection of the ring. The three arms each have a slot 27.

The plate or plates are housed in the slot (s) so as to guide in translation and thus prevent any rotation of the projectile relative to the envelope (see FIG. 5A).

The ends of the arms 14 come to bear on the corresponding tab 25. The plate or plates have a length such that they release the arms when the belt 8 of the projectile has penetrated into the barrel of the weapon.

In this variant, the legs constitute the support means of the arms, the width of the legs is reduced (see FIG. 5A) which makes it possible not to reduce the volume reserved for the propellant charge too much, but to maintain contact between the ends of the arms and legs, it is then necessary to provide a guide means which is constituted by the plate and the slots.

The main advantage of this alternative embodiment is that it dispenses with the installation of a shearable element secured to the arms.

It would also be possible to provide for the plastic plate, possibly made of the same material as the ring.

It would be possible to combine the guide means constituted by the plates and the slots carried by the arms with the bearing means constituted by the bulges, and conversely to provide tabs integral with the ring and carrying grooves.

FIG. 6 shows an alternative embodiment of the munition of FIG. 2.

In this particularly interesting variant, the arms 14 extend to the front part of the shoe 11, while the wedge 15 is integral with the tail unit 10 of the sub-projectile.

The wedge is shown in more detail in Figure 6A.

The advantage of such an arrangement is that it provides guidance for the projectile 4 relative to the ring 3 during the entire movement of the projectile in the casing of the ammunition, which ensures continuity of guidance during the passage of the projectile from the envelope to the barrel of the weapon.

Claims (10)

1. A device for holding and guiding a projectile (4) in relation to the cylindrical casing (2) of a compact-type ammunition round (1) wherein the projectile is confined to the cartridge case, said projectile being of the subcaliber type and comprising a sub-projectile (12) disposed inside a sabot (11) of the same caliber as the weapon barrel, said sabot carrying on its aft section at least three arms (14) at the same angular distance from one another and guiding the projectile inside the barrel of a weapon, said device being characterized in that it comprises, on the one hand an annular bush (3) fitted to the casing and accommodating the fore section of a projectile and, on the other hand a shim (15) integral with the projectile and providing for the support and guidance of said projectile on the inner surface of the casing (2) throughout its travel inside said casing, the shim (15) separating from the projectile when it comes into contact with the bush (3).
2. A holding device as set forth in Claim 1, characterized in that the shim comprises an annular section (16) carrying at least three radial extensions (15a, 15b, 15c) coming into contact with the inner surface of the casing (2).
3. A holding device as set forth in Claim 2, characterized in that the shim (15) is integral with the fins (10) of the sub-projectile (12).
4. A holding device as set forth in Claim 2, characterized in that the shim (15) is integral with the arms (14) of the sub-projectile (12).
5. A holding device as set forth in any of Claims 3 or 4, characterized in that the arms (14) extend up to the fore section of the sabot.
6. A device for holding a guiding a projectile (4), in relation to the cylindrical casing (2) of a compact-type round (1) wherein the projectile is confined to the cartridge case, said projectile being of the subcaliber type and comprising a sub-projectile (12) disposed inside a sabot (11) of the same caliber as the weapon barrel, said sabot carrying on its aft section at 'least three arms (14) at the same angular distance from one another and fulfilling a guidance function inside a weapon barrel, such device being characterized in that it comprises, on the one hand, an annular bush (3) fitted on the casing and accommodating the fore section of the projectile and, on the other hand, fingers (20) carried by each arm (14), holding and guiding the projectile on the inner surface of the casing (2) throughout the travel of said projectile inside said casing, each finger changing, when in contact with the bush, from a deployed position in which it rests on the inner surface of the casing (2) to a retracted position in which the arms (14) carrying the fingers (20) guide the projectile inside the weapon barrel.
7. A device for holding and guiding a projectile (4) in relation to the cylindrical casing (2) of a compact-type round (1) wherein the projectile is confined to the cartridge case,said projectile being of the subcaliber type and comprising a sub-projectile (12) disposed inside a sabot (11) of the same caliber as the weapon barrel, said sabot carrying on its aft section at least three arms (14) at the same angular distance from one another and fulfilling a guidance function inside a weapon barrel, said device being characterized in that it comprises, on the one hand, an annular bush (3) fitted to the casing and accommodating the fore section of the projectile and including at least three lugs (25) integral with the bush (3) at the location of its aft section, at the same distance from one another, in contact with the inner surface of the ring (2) and extending in an axial direction, the arms resting on said lugs and, on the other hand, a guiding means (26 - 27, 18 - 19) precluding every rotation of the projectile (4) in relation to the casing (2).
8. A device for holding a guiding a projectile (4) in relation to a cylindrical casing (2) of a compact-type round (1) wherein the projectile is confined to the cartridge case , said projectile being of the subcaliber-type, and comprising a sub-projectile (12) disposed inside a sabot (11) of the same caliber as the weapon barrel, said sabot carrying on its aft section at least three arms (14) at the same angular distance from one another and fulfilling a guidance function inside a weapon barrel, said device being characterized in that it includes, on the one hand, an annular bush (3) fitted to the casing and, on the other hand, at least three bulges (17) integral with the inner surface of the casing (2) at the same distance from one another, and extending in an axial direction, the arms resting on said bulges, and in that they include also a guiding means (18 - 19, 26 - 27) precluding every rotation of the projectile (4) in relation to the casing (2).
9. A holding device as set forth in any of Claims 7 or 8, characterized in that the guiding means includes, on the one hand, at least one plate (26) carried by a lug (25) or a bulge (17), said plate being parallel to the round axis, extending radially toward the inside of the round and, axially, substantially throughout the length of the lug or of the bulge and, on the other hand, a slot (27) machined in each arm (14), the plate (26) being accommodated in one of the slots (27).
10. A holding device as set forth in any of Claims 7 or 8, characterized in that the guidance means includes, on the one hand, grooves (18) machined in each lug (25) or each bulge (17), said grooves being parallel to the round axis and extending substantially throughout the length of the lug or of the bulge and, on the other hand, at least one shear-pin (19) carried by one of the arms (14) and moving freely inside one of the grooves (18).

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