EP0884553B1 - Propulsive unit for a projectile limiting the recoil energy - Google Patents

Description

The present invention relates to the field of sets of projectile propulsion, in particular the field of tube systems projectile launchers.

The present invention finds in particular, but not exclusively, application in the field of weapons. It is indeed not limited to this preferred application, but can be used in any launcher projectile, such as, for example, rocket launching tubes for fireworks, alarm signals, anti-hail rockets, or even in launch tubes on test benches in which projectiles can be formed by example of trolleys or equivalent, in particular for impact tests, etc ...

Most known projectile tube launching systems include, as shown in Figure 1 attached, a barrel tube 10, a cylinder head or bottom 12 closing the tube 10 at one end and a pressure source 14, generally formed by a cartridge pyrotechnic.

The projectile 20, awaiting the firing, delimits inside the tube 10, a chamber 16 in which the pyrotechnic cartridge 14 is placed.

When fired, the explosion of the pyrotechnic cartridge 14 generates in this chamber 16, a driving pressure for the projectile 20. The latter is set in motion, and the increase in volume of the chamber 16 induces gas expansion until venting to chamber 16 when from the exit of the projectile 20 out of the barrel tube 10 as it is shown schematically in Figure 2. The integral, during this time, of the pressure, multiplied by the section of the barrel tube 10, gives the impetus for the shot.

These known launch tubes have the drawback, on the one hand, of generate a significant backward force felt by the shooter or the support of the launcher tube, on the other hand to require a thick tube wall significant, due to the pressure spike generated immediately after the explosion of the cartridge 14. This peak is particularly harmful for long guns.

We have already tried to limit the retreat effort resulting from this peak pressure by placing damping means between the launcher tube and a reference, for example a shoulder rest, or a support mount for the launch tube.

The Applicant also proposed in document FR-A-2713324 a projectile propulsion unit of the type comprising a room that houses a pressure source and communicates with a space trigger via a passage controlled by a valve control system to control the driving pressure of the projectile and preferably adapted to define a constant pressure in the relaxation room.

WO-A-9107636 describes a projectile comprising timed ejection means of a load. More specifically, this document describes a launcher comprising a pressure source not shown, suitable for launching a projectile. The projectile includes a payload, a first pressure chamber and a second pressure chamber. A valve ensures the supply of the first pressure chamber to from the source. The first pressure chamber communicates by elsewhere with the second pressure chamber through an orifice calibrated. More precisely the second chamber is defined between a piston likely to push the payload and a housing defining the first chamber, the piston and the housing being connected by a shear pin. In in addition, the first chamber is filled, according to the essential characteristic of this document, by a fibrous material. How this projectile works is basically the following. When launching the first room is charged at constant pressure via the valve. Pressure in the second room rises gradually until the pin. The piston then deposits the payload with a sudden rise in the pressure in the second chamber thanks to the passage thus freed from the connection between the two pressure chambers.

The NAVY TECHN document. DISCLOS. BULL., Vol. III, n ° 3, March 1978, DAHLGREN VIRGINIA describes a thruster provided on a system launcher or on a projectile. This document mainly relates to means for adjusting a surface ratio between an orifice leading to the relaxation room and vents.

Document US-A-3628415 teaches a mortar. He describes 5 essentially means for adjusting the free cross section of a passage Wind. A valve formed by a pallet cooperating with the passage serves to evacuation of residual moisture inside the mortar.

GB-A-484346 describes a cartridge comprising a projectile guide means in the form of a central internal tube. A part of the propellant charge is placed inside this tube forming projectile guidance means and another part of the propellant charge is disposed outside of this guide tube. So, to allow on the one hand to guarantee a simultaneous initiation of the two parts of the propellant charge and on the other hand an equi-pressure between the interior and 5 outside the guide tube, the latter is perforated. However, the provision described in this document in no way controls the propulsion pressure, and in particular keep it at least substantially constant.

The present invention now aims to improve the known projectile propulsion systems, in order to improve the performance of these.

A main object of the present invention is to modify the internal ballistic of the launcher tube so that the internal pressure in the tube when firing is as constant as possible.

These aims are achieved in the context of the present invention by to a projectile propulsion unit of the type defined in claim 1 appended.

According to another advantageous characteristic of the invention, the arrangement (including distribution, number and size) of the bores provided in the rod is suitable for ensuring propulsion pressure at least substantially constant in the launcher tube.

According to another advantageous characteristic of the invention, the rod with bores distributed over its length is interposed between the chamber which houses the pressure source and the expansion chamber which ensures projectile propulsion.

The present invention also relates to suitable projectiles to be fired from such a power package.

• la figure 1 précédemment décrite représente une vue schématique en coupe axiale d'un tube lanceur classique,
• la figure 2 précédemment mentionnée représente l'impulsion motrice dans un tel tube lanceur classique,
• la figure 3 représente une vue schématique en coupe longitudinale, avant lancement d'un dispositif conforme à un premier mode de réalisation de la présente invention,
• les figures 4a, 4b, 4c représentent des vues similaires d'un dispositif conforme à un second mode de réalisation de la présente invention, à trois étapes successives de lancement d'un projectile, et
• la figure 5 représente la pression dans le tube lanceur conforme à la présente invention.

Other characteristics, aims and advantages of the present invention will appear on reading the detailed description which follows and with reference to the appended drawings, given by way of nonlimiting examples and in which:

• FIG. 1 previously described represents a schematic view in axial section of a conventional launcher tube,
• FIG. 2 previously mentioned represents the driving impulse in such a conventional launching tube,
• FIG. 3 represents a schematic view in longitudinal section, before launching a device according to a first embodiment of the present invention,
• FIGS. 4a, 4b, 4c show similar views of a device according to a second embodiment of the present invention, in three successive stages of launching a projectile, and
• Figure 5 shows the pressure in the launcher tube according to the present invention.

The propulsion assembly according to the present invention includes a launcher tube 100.

It is a launcher tube 100 with closed barrel, that is to say the bottom is closed by a cylinder head 110 or equivalent.

The starter tube receives a pressure source 120. These are preferably a pyrotechnic cartridge. However, the source of pressure 120 can be formed by any equivalent means.

The tube 100 is adapted to receive a projectile 200. This is adapted to the internal gauge of the tube 100 as seen in the figures attached.

As mentioned earlier, in the context of this invention, the chamber which houses the pressure source 120 communicates with a rod 130 placed in the launcher tube 100. The rod 130 comprises bores 132 distributed over its length to be released successively when projectile 200 is ejected.

Very preferably, there is provided a single rod 130 centered on the axis O-O of the tube 100. However, if necessary, provision can be made several rods 130 evenly distributed around the axis O-O.

Note that according to the embodiments illustrated in the attached figures, the projectile 200 is provided with a chamber 210 opening on its rear end, which chamber 210 is adapted to the diameter outside of the rod 130. Thus the projectile 200 originally covers the majority of the bores 132 but gradually releases these during its displacement.

The tube 100 and the projectile 200 can be the subject of numerous embodiments. They will therefore not be described in detail by the after.

Note, however, that according to the embodiment illustrated in the Figure 3, the pressure source or pyrotechnic cartridge 120 is placed directly into the rod 130 so that the chamber 122 which houses the pressure source 120 communicates directly with chamber 140 which receives the projectile 200 via the bores 132.

However, according to the embodiment illustrated in FIGS. 4a, 4b and 4c, an intermediate chamber 150 is interposed between the chamber very high pressure 122 which houses the source 120 and the chamber 140 receiving the projectile 200. This intermediate chamber 150 high pressure communicates with the internal volume of the rod 130.

Of course, the rod 130 is closed at its front end by a transverse partition 134 so that the only possible communication between the internal volume of the rod 130 and the chamber 140 receiving the projectile 200 corresponds to bores 132.

In the firing standby position, at least one of the orifices 132 formed in the rod 130 communicates with said chamber 140 receiving the projectile 200, to allow high pressure gas circulation at from the internal volume of the rod 130 towards this chamber 140. This orifice is illustrated under reference 132a in the appended figures. According to the figure 3, it is the orifice (s) closest to the cylinder head 110.

On the other hand, according to FIGS. 4a to 4c, the orifice (orifices) 132 which leads (s) initially into room 140 is the one (s) located (s) the foremost, that is to say the closest to the wall 134 (according to FIGS. 4a at 4c, this orifice 132a is then temporarily closed by the projectile 200 after the start of the shot and before the projectile 200 leaves the tube 100).

The projectile 200 can be held in the tube 100 before firing by any suitable conventional means, for example by pins sheared.

According to the embodiment illustrated in FIGS. 4a to 4c, the projectile 200 is provided with a tail unit 220 at its rear end.

This empennage 220 is adapted to initially seal all of the orifices 132 of the cane with the sole exception of the aforementioned orifice 132a.

As previously indicated, in the context of this invention, the arrangement of the orifices 132, in particular their distribution, size and number, is suitable for ensuring propulsion pressure at least substantially constant in the propulsion chamber 140.

For this, as can be seen in the appended figures, the wall of the rod 130 perforated by the openings 132 is inserted directly or indirectly (via the high pressure chamber 150) between the chamber which houses the pressure source 120 and the propulsion chamber 140.

The operation of the propellant assembly in accordance with this invention, essentially comprises three successive phases.

The pressure prevailing in the launcher tube 100 during these three successive faces is illustrated by way of nonlimiting example in FIG. 5.

When ignited, the pyrotechnic cartridge 120 (or the source equivalent pressure formed for example from a gas source compressed) generates very high pressure gases which fill the rod 130 (directly according to FIG. 3 and after transit via the chamber 150 according to FIG. 4) and flow into chamber 140 via the bore (or bores) 132a. Following this flow through of bore 132a, the driving pressure will increase in chamber 140 during a phase referenced phase 1 in Figure 5 to reach a regulation pressure at the end of this phase 1. Projectile 200 is moved in the tube 100 with the increase in this driving pressure.

Preferably, in the context of the second illustrated embodiment in FIGS. 4a to 4c, thanks to the displacement of the projectile 200 during this phase 1, the initial passage section 132a is completely closed at the end of this phase 1, but on the other hand the rear bores 132 are discovered.

During the second phase illustrated in Figure 5, the displacement of the projectile 200 unmask as the bores 132 formed in the rod 130 to maintain in the form of a plate substantially constant driving pressure in room 140. Progressive release bores 132 increases the fluid flow rate between the source of pressure 120 and the launching chamber 140 to maintain the pressure drive at an at least substantially constant value.

A third phase begins when the 200 projectile has exposed all orifices 132. The driving pressure can no longer be maintained at a constant regulation threshold. Then begins a low relaxation phase pressure as illustrated in figure 5.

In FIGS. 4a, 4b and 4c, the projectile 200 is illustrated respectively in the positions occupied in phase 1, phase 2 and phase 3 of Figure 5.

Of course, the number, size and position of the bores 132 must be adapted according to the power of the pressure source 120, the caliber and mass of the 200 projectile.

By way of nonlimiting example, for a 200 caliber 3 projectile inches (7.62 cm), the rod 130 has a length of 120 mm and a diameter 26 mm and it has 24 bores 132 formed of circular orifice with a diameter of the order of 2 mm distributed with a variable pitch from 21 to 12 mm along the length of the rod 130 and also provided with 3 holes 132a with a diameter of 1.5mm.

Of course the propulsion device in accordance with this invention can be combined with any other known structure capable of to reduce the retraction force of the tube 100, for example all means shock absorbers compatible with this propulsion system.

The present invention finds particular application in shoulder shooting systems.

The present invention offers many advantages over known prior systems.

• une réduction des efforts de propulsion sur le projectile 200, donc possibilité de réduire la masse de sa structure et, à masse de projectile donnée, possibilité d'augmenter sa charge utile,
• une réduction de la course de recul du tube 100 à impulsion et effort amortisseur fixés : cela minimise le déplacement du centre de gravité de l'arme en cours de tir, donc les perturbations liées à ce mouvement (bruit de visée, mouvement de rotation du tireur dans le plan vertical) ; cela réduit aussi la durée d'application de l'effort appliqué au tireur ce qui améliore le confort de tir,
• une réduction de l'effort amortisseur à course de recul du canon et impulsion fixées : cela minimise l'effort appliqué au tireur ce qui améliore le confort de tir ;
• une augmentation de l'impulsion de tir à effort amortisseur et à course de recul du canon 100 fixés ; cela augmente les performances de tir pour un confort inchangé,
• une réduction de la pression interne maximale régnant dans le tube 100 d'où la possibilité de réduire l'épaisseur du tube 100 et d'alléger celui-ci.

By way of nonlimiting example, there will be mentioned:

• a reduction in propulsion forces on the projectile 200, therefore possibility of reducing the mass of its structure and, with a given projectile mass, possibility of increasing its payload,
• a reduction in the recoil stroke of the tube 100 with fixed impulse and damping force: this minimizes the displacement of the center of gravity of the weapon during firing, therefore the disturbances linked to this movement (aiming noise, rotation movement of the shooter in the vertical plane); this also reduces the duration of application of the force applied to the shooter, which improves shooting comfort,
• a reduction in the shock absorbing force at the barrel recoil stroke and fixed pulse: this minimizes the force applied to the shooter, which improves shooting comfort;
• an increase in the firing pulse at shock absorbing force and at recoil stroke of the barrel 100 fixed; this increases shooting performance for unchanged comfort,
• a reduction in the maximum internal pressure prevailing in the tube 100, hence the possibility of reducing the thickness of the tube 100 and making it lighter.

Rod 130 can be integrated into the cylinder head not consumable from a cannon or in a consumable socket secured to a projectile.

Claims (14)

1. A projectile propulsion assembly of the type comprising a chamber (122) which houses a pressure source (120), and which communicates with at least one pipe (130) placed inside the launch tube (100) and having bores (132) distributed along its length so as to be released in succession during ejection of the projectile (200), the assembly being characterized by the fact that the wall of the pipe (130) provided with the bores (132) is interposed between the chamber housing the pressure source (120) and the expansion chamber (140) that propels the projectile.
2. An assembly according to claim 1, characterized by the fact that the pipe (130) houses the pressure source (120).
3. An assembly according to claim 1 or claim 2, characterized by the fact that an intermediate high pressure chamber (150) is interposed between the chamber (122) which receives the pressure source (120) and the inside volume of the pipe (130).
4. An assembly according to any one of claims 1 to 3, characterized by the fact that it includes a projectile (200) provided with a chamber (210) which opens out at its rear surface, which chamber (210) is matched to the outside diameter of the pipe (130).
5. An assembly according to any one of claims 1 to 4, characterized by the fact that at least one of the bores (132a) of the pipe (130) opens out initially freely into the chamber (140) which receives the projectile (200).
6. An assembly according to claim 5, characterized by the fact that the bore (132a) which opens out initially into the chamber (140) receiving the projectile (200) is the rearmost bore (132a) formed in the pipe (130).
7. An assembly according to claim 5, characterized by the fact that the bore (132a) which opens out initially into the chamber (140) receives the projectile (200) is an orifice which is temporarily closed by the projectile (200) after firing has been initiated, because of the displacement of the projectile.
8. An assembly according to claim 7, characterized by the fact that the orifice (132a) which opens out initially into the chamber (140) receiving the projectile (200) is temporarily closed by the tail fin of the projectile (200) following displacement of the projectile.
9. An assembly according to any one of claims 1 to 8, characterized by the fact that the pipe (130) is centered inside the tube (100).
10. An assembly according to any one of claims 1 to 8, characterized by the fact that it comprises a plurality of pipes (130) provided with bores (132), the pipes being uniformly distributed about the axis O-O of the tube (100).
11. An assembly according to any one of claims 1 to 10, characterized by the fact that the pressure source (120) is integrated in the launch tube (100).
12. An assembly according to any one of claims 1 to 11, characterized by the fact that the pressure source (120) is placed inside a pipe (130) integrated in the non-consumable breech of a barrel.
13. An assembly according to any one of claims 1 to 11, characterized by the fact that the pressure source (120) is placed inside a pipe (130) integrated in a consumable cartridge.
14. A projectile for a propulsion assembly according to any one of claims 1 to 13, characterized by the fact that it includes a chamber (210) opening out to its rear end and matched to the outside calibre of the pipe (130).

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