Telescopic ammunition with a sub-caliber projectile stabilized by an extendable guide device

Description

FIELD OF THE INVENTION

[0001] The technical field of the present invention is that of telescoped type munitions comprising a sub-caliber projectile. STATE OF THE ART

[0002] These telescoped-type munitions generally have a substantially cylindrical case, inside which are arranged a set of projectiles and a propellant charge.

[0003] The entire projectile assembly is located inside the case. It may consist of a single-piece projectile, of the weapon's caliber, or be formed by a sub-caliber projectile and a sabot, of the weapon's caliber, which surrounds and holds the sub-caliber projectile.

[0004] The present invention is particularly applicable to such telescoped munitions containing a projectile assembly formed by a sub-caliber projectile and a sabot.

[0005] When firing ammunition containing a sub-caliber projectile, the projectile assembly consisting of the sabot and the sub-caliber projectile is propelled into the barrel of the weapon. Upon exiting this barrel, the sabot detaches from the sub-caliber projectile, which then continues its trajectory.

[0006] To travel a predictable trajectory over a long distance, the projectile exiting the gun barrel must be stabilized.

[0007] This stabilization can be a gyroscopic stabilization, resulting from a rapid rotation of the projectile around its longitudinal axis, imparted to the projectile by the rifled tube of the weapon. Such stabilization is generally implemented for projectiles of the caliber of the weapon. It can also be implemented for sub-caliber projectiles. In this case, the sliding belt which surrounds the sabot, and which is in contact with the rifled tube of the weapon, transmits a rotation to the entire projectile.

[0008] However, when the projectile is under-caliber, the spin that is transmitted by the slip belt may not be sufficient to stabilize the projectile satisfactorily.

[0009] Furthermore, ammunition projectiles increasingly allow the carriage of charges such as explosive charges, electronic components or gyroscopes. Such charges can be sensitive to excessively rapid rotation of the projectile, which can impair their operation.

[0010] Stabilization by tail of the sub-caliber projectile

[0011] It is also known to ensure aerodynamic stabilization of the projectile on its trajectory using a tail. The tail ensures a stable trajectory of the projectile over very long distances, for example, over 3 km. Sub-caliber projectiles equipped with tails are generally driven by a rotational movement at a moderate speed much lower than gyro-stabilized projectiles.

[0012] Thus, patent FR-2647891, which corresponds to the preamble of claim 1, discloses a telescoped munition comprising a projectile assembly, consisting of a sabot and a sub-projectile equipped with a tail. Documents US4802415A and GB2136930A are also relevant documents of the prior art.

[0013] Limitations of prior art tail stabilization

[0014] However, such stabilization by tailing of a sub-caliber projectile can only be applied to projectiles of relatively small diameter compared to the caliber of the weapon. Indeed, to ensure stabilization effectively, the span of the tail, which must be less than the caliber of the weapon, must be greater than the diameter of the body of the sub-caliber projectile.

[0015] However, there is a need for relatively large projectiles stabilized by tails, to allow the carriage of explosive charges, electronic components, for example for tracking moving targets, or a gyroscope to determine the trajectory of the projectile. Such charges occupy a significant amount of space and can be disturbed by the projectile rotating too quickly. Statement of the invention

[0016] The aim of the present invention is therefore to propose a telescoped ammunition, comprising a sub-caliber projectile, making it possible to overcome such drawbacks.

[0017] In particular, the invention aims to propose such ammunition in which the sub-caliber projectile has relatively large dimensions, compared to the caliber of the weapon barrel.

[0018] Another aim of the invention is to propose such ammunition in which the sub-projectile is effectively stabilized, without undergoing too rapid a rotation likely to disrupt the operation of the charge it carries.

[0019] The invention therefore relates to a telescoped-type ammunition, comprising a case inside which are housed a sub-caliber projectile equipped with a segmented ejection sabot, a propellant charge and a device for igniting the propellant charge, characterized in that said sub-caliber projectile comprises an extension receiving a tail movable between a position folded against said extension and a deployed position, said sabot holding said tail in said folded position, and in that said tail comprises fins fixed in an articulated manner relative to the extension of the sub-caliber projectile by means of hinges with axes parallel to the longitudinal axis of the sub-caliber projectile.

[0020] According to a characteristic of the invention, said sabot envelops said empennage to isolate it in order to prevent contact between said empennage and said propellant charge.

[0021] According to yet another characteristic of the invention, each of said fins is movable between: 1. a stowed position, in which each fin extends along an external surface of said sub-caliber projectile, and 2. a deployed position, in which each fin extends radially around the extension of the sub-caliber projectile.

[0022] Advantageously, said hinges are equipped with stops preventing the pivoting of said fins outside an angular range between said folded position and said deployed position. If necessary, keys can be used to prevent the fins from closing on the trajectory.

[0023] According to yet another characteristic of the invention, the empennage has, in said deployed position, a diameter greater than the caliber.

[0024] Advantageously, the case consists of a substantially cylindrical envelope, one end of which is closed by a base, and the other end is equipped with a guide ring, in which said projectile is engaged.

[0025] According to yet another characteristic of the invention, the sabot has, over at least part of its length, an external section which is substantially cylindrical in caliber and an external section which is substantially cylindrical in caliber over the entire length of said sub-caliber projectile.

[0026] According to yet another characteristic of the invention, the extension of the sub-caliber projectile comprises flat faces aligned with the longitudinal axis of the sub-caliber projectile on which the fins are folded down in the folded position. Brief description of the drawings

[0027] Other characteristics, details and advantages of the invention will emerge more clearly from the detailed description given below for information purposes in relation to drawings in which: [ Fig. 1 ] there Figure 1 represents in axial section a munition according to an embodiment of the invention; [ Fig.2 ] there Figure 2 represents the projectile assembly of the ammunition of the Figure 1 , part of the sabot of which has been removed to allow the sub-caliber projectile to be seen; [ Fig. 3 ] there Figure 3 represents the sub-caliber projectile of the ammunition of the Figure 1 , outside the hoof; [ Fig.4 ] there Figure 4 is a cross-section of the projectile assembly of the ammunition of the Figure 1 , at the level of the tail of the sub-caliber projectile; [ Fig.5 ] there Figure 5 is a cross-section of the sub-caliber projectile of the ammunition of the Figure 1, outside the sabot, at the level of its deployed tail. DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

[0028] The invention will now be described in greater detail.

[0029] There Figure 1 represents, in sectional view along the longitudinal axis, a telescoped type munition 1. Such a munition comprises a case, consisting of a cylindrical casing 2, closed by a base 3 and a guide ring 6.

[0030] The base 3 closes the rear end of the casing 2. It is preferably metallic and carries, in its center, an ignition device 4 of known type, conventionally comprising a primer and an ignition relay (not described). The base 3 is linked to the casing by means of a lip 5, which can be made of plastic.

[0031] The guide ring 6 is placed at the front end of the casing 3. It is preferably made of plastic and is reinforced by a metal ring 7. This guide ring 6 has a tubular shape, which defines an axial bore, at the caliber of the weapon intended to fire the ammunition.

[0032] The case of the ammunition 1 comprises a propellant charge 8 surrounding a projectile 9 consisting of a sub-caliber projectile 16 which is integrated into an ejectable segmented sabot 11, the front end of which is at the caliber of the weapon and is engaged in the axial bore of the guide ring 6.

[0033] Projectile 9 is also represented, outside the case, by the Figure 2 . In this figure, however, only half of the sabot 11 is shown, so as to make the sub-caliber projectile 16 visible.

[0034] This projectile 9 is intended to be propelled out of the case of the ammunition 1, after its journey through the weapon tube, under the effect of the pressure generated by the combustion of the propellant charge 8.

[0035] The sabot 11, which may be made of aluminum, has a generally cylindrical external shape, in the caliber of the barrel of the weapon in which it is to be engaged. In a manner known per se, this sabot 11 is made up of several segments, four segments in the embodiment shown, which are separable from each other at the outlet of the barrel. On the Figure 2 , only two of these segments are represented.

[0036] These four segments are held in contact with each other, and against the sub-caliber projectile 16, by a sliding belt 12 (not shown on the Figure 2 ) fitted into a peripheral bore of the shoe 11, near the front end of this shoe 11.

[0037] This slip belt 12 is preferably formed of a plastic material allowing it to deform when the sabot 11 passes through the axial bore of the guide ring 6, then into the barrel of the weapon. In a known manner, the slip belt 12 then ensures the seal between the projectile assembly 9 and the barrel of the weapon. When the barrel of the weapon is rifled, this slip belt 12 can also transmit to the projectile assembly 9 a rotation imparted by the helical rifling of the barrel.

[0038] At the exit of the weapon barrel, the segments forming the sabot 11 tend to move away from each other, under the effect of centrifugal force or aerodynamic forces. This separation causes the slip belt 12 to break, and the segments of the sabot 11 to separate from the sub-caliber projectile 16, which then continues its trajectory. The slip belt 12 may have, in a known manner, incipient ruptures facilitating this separation.

[0039] The segments of the sabot 11 are also held in contact with each other, and against the sub-caliber projectile 16, by a holding ring 13 (not shown in the Figure 2 ) fitted into a peripheral bore of the shoe 11 near the rear end of this shoe 11. In the same way as the slip belt 12, this retaining ring 13, preferably made of plastic, is intended to break when the segments of the shoe 11 are separated.

[0040] The sabot 11 has an axial bore shaped to receive and hold the sub-caliber projectile 16.

[0041] This 16 sub-caliber projectile is represented, apart from sabot 11, by the Figure 3 It extends along a main axis, which corresponds to the firing axis of ammunition 1.

[0042] The sub-caliber projectile 16 is formed of several components assembled together. At its front end, it has a warhead 14, preferably metallic. In the embodiment shown, this warhead is made of aluminum, and is equipped with small canard planes intended to participate in guiding the sub-caliber projectile 16 towards the target.

[0043] The axial bore of the shoe 11 has, at the level of this ogive 14, an enlarged diameter making it possible to surround these canard planes.

[0044] The warhead 14 is assembled on the front of a projectile body 15, preferably made of a metallic material such as tungsten. This projectile body 15 is followed by an extension 10 and has an internal chamber 16 in which a charge, such as an explosive charge or electronic components, for example for projectile guidance, can be placed. The external surface of this projectile body 15 has a thread, or peripheral grooves. The axial bore of the sabot 11 preferably has, at the level of this projectile body 15, a shape complementary to this thread or these grooves, in order to secure the sabot 11 to the sub-caliber projectile 16, in the axial direction.

[0045] This internal chamber 18 is closed at the rear by a plug 17.

[0046] The axial bore of the sabot 11 is itself closed, at the rear by the plug 17 protecting the rear of the sub-caliber projectile 16. This plug 17 can be held by the segments of the sabot 11. Preferably, it is also fixed to the ignition device 4, which ensures that the projectile assembly 9 is held in the correct position in the case.

[0047] During combustion of the propellant charge, the pressure increase in the ammunition causes this attachment to break, to allow the closing plate to be propelled into the weapon tube, with the projectile assembly 9.

[0048] On the extension 10 close to the rear end of the sub-caliber projectile 16, a tail 19 is provided which in the embodiment shown is made up of four fins 19a, 19b, 19c and 19d distributed angularly around the tail of the sub-caliber projectile 16. Each fin is positioned in a folded position on a flat surface provided at the level of the extension 10. We see on the Figure 3 the flat surface 21 onto which the fin 19c can be folded into the folded position.

[0049] It goes without saying that this empennage 19 is deployable, the fins 19a, 19b, 19c and 19d being movable between a folded position and a deployed position.

[0050] The 19th tail is thus represented in its folded position on the Figures 1 and 2 , as well as on the Figure 4 which is a cross-section of the projectile assembly 9, at the level of the extension 10 carrying this tail.

[0051] The 19th tail is instead shown in its deployed position on the Figure 3 as well as on the Figure 5 , which is a cross-section of the sub-caliber 16 projectile at the level of the extension 10 carrying this tail.

[0052] To be movable between these two positions, the fins 19a, 19b, 19c and 19d forming the tail 19 are each pivotally mounted, on the extension 10 of the sub-caliber projectile 16, around a hinge, respectively 20a, 20b, 20c and 20d, the axes of which are substantially parallel to the longitudinal axis of the sub-caliber projectile 16.

[0053] Preferably, as shown by the figures 5and 6, the extension 10 of the projectile 9 has in section, at the level of the tail 19, a substantially square external section. The hinges, respectively 20a, 20b, 20c and 20d, of the fins 19a, 19b, 19c and 19d, are placed along the edges of this square section, in such a way that each fin 19a, 19b, 19c and 19d can, in its folded position, extend against each of the substantially flat faces 21 with a square section of the extension 10 of the sub-caliber projectile 16.

[0054] Preferably, the internal shape of the axial bore of the sabot 11 matches, at the level of the tail 19, the shape of the fins in this folded position, as illustrated in Figure 4which shows the segments 11a, 11b, 11c and 11d of the sabot 11. The sabot 11, when it surrounds the sub-caliber projectile 16, therefore maintains the fins 19a, 19b, 19c and 19d of the tail 19 in their folded position on the corresponding flat face 21. This tail 19 then has a very reduced span, less than the caliber of the weapon barrel.

[0055] When, at the exit of the barrel of the weapon, the segments 11a, 11b, 11c and 11d of the sabot 11 separate from the sub-caliber projectile 10, the fins 19a, 19b, 19c and 19d are no longer held in their folded position. These fins 19a, 19b, 19c and 19d then pivot, around their respective hinges 20a, 20b, 20c and 20d, to their deployed position.

[0056] Preferably, this pivoting is done under the effect of centrifugal force, as well as under the effect of aerodynamic forces, the pivoting of each fin from its folded position to its deployed position being done in a direction opposite to the direction of rotation of the projectile 9 in the air. It is also possible, in other embodiments, that springs are provided to drive the fins from their folded position to their deployed position.

[0057] In their deployed position, the fins 19a, 19b, 19c and 19d preferably extend in a radial direction, relative to the longitudinal axis of the sub-caliber projectile 16. The hinges 20a, 20b, 20c and 20d are advantageously equipped with stops preventing the fins 19a, 19b, 19c and 19d from pivoting beyond this radial orientation which corresponds to their deployed position.

[0058] In this position of the fins 19a, 19b, 19c and 19d, the tail 19 in the deployed position has a large span, greater than the caliber of the weapon barrel. It can then effectively stabilize the sub-caliber projectile 16 which can thus travel a trajectory of great length.

[0059] The sub-caliber projectile of a telescoped ammunition according to the invention can thus be effectively stabilized by the tail while having a large diameter, compared to the caliber of the weapon barrel. This feature gives it a load-carrying capacity greater than the sub-caliber projectiles of telescoped ammunition of the prior art. For example, in the embodiment shown, the sub-caliber projectile has a diameter of approximately 20 mm, while the diameter of the weapon is 40 mm.

[0060] The solution of the invention therefore allows the carriage of larger charges in a telescoped ammunition projectile. It also allows this charge to be subjected only to rotation at relatively low speed, which reduces the risk of malfunction of the charge linked to the rotation of the projectile.

[0061] It should also be noted that this solution of the invention makes it possible to implement relatively low-caliber munitions equipped with a deployable tail, which therefore includes small mechanical elements. This implementation is made possible by the fact that the sabot completely envelops the tail, in its folded position. When the pressure in the munition increases, the tail is thus protected by the sabot, which prevents it from being damaged.

[0062] A person skilled in the art will be able to easily make variations to the solution presented, without departing from the scope of the present invention. In particular, he will be able to adapt the solution of the invention to telescoped-type munitions of various calibers.

[0063] It will also be possible to implement the deployable tail according to the invention with a different number of fins by providing the necessary flat surfaces. Thus, it is possible to manufacture such a tail with two or three fins, or with five or even six fins.

[0064] In this case, the external section of the sub-caliber projectile at the tail may be chosen so that each of the fins can, in its folded position, extend against one of the substantially flat external faces. This section may, for example, be triangular if there are three fins, pentagonal if there are five fins or hexagonal if there are six fins.

[0065] Similarly, it is advantageous for the sabot to be divided into a number of segments identical to the number of fins, but it is also possible to provide a different configuration of the sabot. It is thus possible, for example, to assemble a sabot divided into three segments on the sub-caliber 16 projectile which carries four fins. The three segments will then have to be machined so as to form together a sabot whose axial bore will have a shape complementary to the shape of the tail in the folded position.

Claims

1. - A telescoped type ammunition (1) comprising a case (2) inside which is housed a sub-calibre projectile (16) equipped with a segmented discarding sabot (11), a propellant charge (8) and an igniting device (4) for the propellant charge, characterised in that said sub-calibre projectile (16) incorporates a prolonged part (10) receiving a tail fin (19) able to move between a folded position against said prolonged part and a deployed position, said sabot (11) retaining said tail fin (19) in said folded position, and in that said tail fin (19) comprising blades (19a, 19b, 19c, 19d) that are hinged with respect to the prolonged part (10) of the sub-calibre projectile (16) by means of hinges (20a, 20b, 20c, 20d) with their axes parallel to the longitudinal axis of the sub-calibre projectile (16).

2. - The ammunition (1) according to claim 1, characterised in that said sabot (11) encloses said tail fin (19) to isolate it so as to prevent any contact between said tail fin (19) and said propellant charge (8).

3. - The ammunition (1) according to claim 1 or 2, characterised in that each of said blades (19a, 19b, 19c, 19d) is able to move between: a folded position in which each blade (19) extends along an external surface of said sub-calibre projectile (16), and a deployed position in which each of said blades (19) extends radially around the prolonged part (10) of the sub-calibre projectile (16).

4. - The ammunition (1) according to claim 3, characterised in that said hinges (20a, 20b, 20c, 20d) are provided with limit stops preventing said blades (19a, 19b, 19c, 19d) from pivoting out of an angular range lying between said folded position and said deployed position.

5. - The ammunition (1) according to any one of the preceding claims, characterised in that said tail fin (19), in said deployed position, has a diameter that is greater than the calibre.

6. - The ammunition (1) according to any one of the preceding claims, characterised in that said case is constituted by a substantially cylindrical casing (2) one end of which is closed by a rear end cap (3), the other end being fitted with a guide tube (6), in which said projectile (9) is engaged.

7. - The ammunition (1) according to any one of the preceding claims, characterised in that said sabot (11) has, along at least part of its length, a substantially cylindrical external section at the full calibre.

8. - The ammunition (1) according to the preceding claim, characterised in that said sabot (11) has a substantially cylindrical external section at the full calibre over the full length of said sub-calibre projectile (16).

9. - The ammunition (1) according to any one of the preceding claims, characterised in that the prolonged part (10) of the sub-calibre projectile (16) incorporates plane faces (21) aligned on the longitudinal axis of the sub-calibre projectile (16) onto which the blades (19) are folded back in their folded position.