EP1693645B1 - Artillery projectile having a driving band - Google Patents

Abstract

The projectile (1) comprising a body (2) with a seal band (4) fastened to it by a mounting ring (6) and a fixing with a threaded rim (7) engaging with the projectile base. The latter has a series of deformable tongues separated by slots, and the rim surrounds a cylindrical recess containing a piston (14) that can slide between locked and unlocked positions controlling the flexure of the tongues. The piston also has an axial projection (17) with a bore and valve (19) that controls the discharge of gases.

Description

The technical field of the invention is that of artillery projectiles comprising a body on which is fixed a sealing belt.

It is conventional to provide a projectile with such a belt which is intended to ensure when firing the seal against the propellant gases between the projectile and the barrel of the weapon.

When the projectile is of the gyro-stabilized type, the belt is generally metallic. It takes the scratches from the barrel of the weapon and communicates a rotational movement to the projectile body. This configuration is the one generally used for artillery fire, the artillery tubes being always scratched.

Today, projectiles carrying a voluminous payload are carried out, for example projectiles that can be guided or self-guided on their trajectory. These projectiles have a larger mass and they generally include a deployable empennage that also occupies a certain place in the room.

These projectiles reduce the volume available for the propellant gases during firing. This results in a loss of ballistic performance.

In order to overcome this problem, it is known from the patent EP905473 (Base for the preamble of claim 1) to arrange the empennage forward of the belt. Thus the empennage does not enter the chamber and the volume devolved to the gas is preserved.

According to this patent the belt is secured to a rear shoe which maintains the empennage and which is ejected during shooting with a suitable gas generating composition.

It is the object of the invention to provide such a projectile in which the ejection of the rear shoe at the exit of the barrel of the weapon is ensured in a reliable and simple manner without it being necessary in particular to put a specific pyrotechnic composition.

Thus the invention relates to an artillery projectile comprising a body on which is fixed a sealing belt, belt attached to the body of the projectile via a mounting ring connected to the projectile body by means of releasable fastening at the exit of the barrel of the weapon, projectile characterized in that the fastening means comprises a threaded flange receiving the mounting ring of the belt, flange integral with a bottom of the projectile and which is formed of separate deformable tabs by slits, the flange further delimiting a cylindrical housing receiving a piston sliding between two positions: a locking position in which it is engaged in the housing, against the flange, and prevents the bending of the tongues and an unlocking position in which he releases the tongues.

The piston may carry an axial extension carrying at least one bore, an extension which will penetrate into a chamber arranged inside the rear part of the projectile.

Advantageously, the extension may contain a sliding valve which during firing will let the propellant gases into the chamber, the pressure of the gases in the chamber pushing the exit of the barrel of the weapon the valve against a seat integral with the piston.

The extension may be closed by a perforated shutter on which will apply a rear portion of the valve during firing, the rear portion of the valve having a stud surrounded by a shoulder on which opens at least one longitudinal groove of the valve, the propellant thus, when firing enter the projectile chamber through the groove or grooves and perforations of the shutter.

The mounting ring of the belt may comprise an abutment surface on which the piston is applied when it is in the unlocking position at the exit of the barrel of the weapon.

The chamber located at the rear of the projectile may contain a propellant charge block providing a reduction of aerodynamic drag on trajectory.

The threaded rim may be integral with a bottom ensuring a partial closure of the chamber.

• la figure 1 montre en vue latérale un projectile selon invention,
• la figure 2a est une vue en coupe longitudinale de la partie arrière du projectile selon l'invention, projectile représenté au repos avant tir
• la figure 2b est une vue analogue à la précédente le projectile étant en phase de parcours du tube de l'arme,
• la figure 2c est une vue analogue aux précédentes le projectile étant représenté à la sortie du tube de l'arme,
• la figure 2d montre le projectile peu de temps après sa sortie du tube de l'arme,
• les figures 3a et 3b montrent de façon isolée le fond portant le rebord fileté, la figure 3a étant une coupe longitudinale et la figure 3b une vue du fond suivant la direction F1,
• les figures 4a et 4b montrent de façon isolée le clapet, la figure 4a étant une coupe longitudinale et la figure 4b une vue du clapet suivant la direction F2.

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 shows in side view a projectile according to the invention,
• Figure 2a is a longitudinal sectional view of the rear part of the projectile according to the invention, projectile shown at rest before shooting
• FIG. 2b is a view similar to the preceding one, the projectile being in the phase of travel of the tube of the weapon,
• FIG. 2c is a view similar to the preceding ones, the projectile being represented at the exit of the tube of the weapon,
• FIG. 2d shows the projectile shortly after its exit from the barrel of the weapon,
• FIGS. 3a and 3b show in an isolated manner the bottom bearing the threaded flange, FIG. 3a being a longitudinal section and FIG. 3b a bottom view in the F1 direction,
• Figures 4a and 4b show the valve in isolation, Figure 4a being a longitudinal section and Figure 4b a view of the valve in the direction F2.

Figure 1 shows a projectile 1 according to the invention. This projectile comprises a body 2 carrying at its front part an ejectable shoe 3 and at its rear part a belt 4.

The belt 4 is secured to a mounting ring 6 extended by a case 5 which provides, as described by the patent EP905473 , maintaining folded stabilizer stabilizer (not shown).

According to an essential characteristic of the invention, means are provided which make it possible to eject the belt 4 at the exit of the barrel of the weapon.

Such an arrangement makes it possible to ensure the deployment of the empennage right out of the tube of the weapon.

It also reduces aerodynamic drag on the trajectory.

FIG. 2a makes it possible to better specify the means making it possible to ensure the ejection of the belt 4 and the case 5. These means comprise a mounting ring 6 which makes it possible to fix the belt 4 to the projectile 1.

This mounting ring 6 is connected to the body 2 by a fastening means designed to be automatically unlocked at the exit of the barrel of the weapon (not shown).

The mounting ring 6 comprises a cylindrical seat 6a receiving the belt 4 and an internal thread 6b which cooperates with a threaded flange 7 secured to the rear end of the body 2 of the projectile.

The tapping 6b of the ring 6 ends with a counterbore 6c which serves as a stop for the ring 6 when it is screwed onto the flange 7. Furthermore, the ring 6 has an internal flange 8 which is disposed at a distance from the counterbore 6c and which plays the role of a stop surface as will be described later.

The threaded rim 7 is integral with a bottom 9 providing a partial closure of a chamber 10, arranged at the rear of the projectile 2, and inside which is disposed a block 11 of a propellant charge ensuring reduced aerodynamic drag of the projectile 1 on trajectory.

These blocks are well known to the skilled person under the name Anglo-Saxon "Base bleed" (or exuding pellet).

Block 11 is initiated by the propellant gases when firing the projectile. It is the same for the pyrotechnic device 12 whose function is to re-ignite the block 11 in case of extinction during the passage to the mouth of the weapon.

The bottom 9 is shown alone in Figures 3a and 3b. It is seen that it carries a thread 9a on its entire external surface which allows its attachment to the body 2 of the projectile.

The bottom 9 has on one of its ends a rounded profile 9b which ensures the wedging of the base-bleed block 11 and on the other end a cylindrical housing 13 which is intended to receive a piston 14 (see Figure 2a).

The housing 13 is delimited by the end of the bottom 9 which forms the threaded rim 7. The bottom 9 is also traversed by an axial bore 24.

As is more particularly visible in FIGS. 3a and 3b, flange 7 is slotted and formed of deformable tabs 15 separated by slots 16.

These tongues 15 are deformable radially in flexion. However, when the piston 14 is disposed in the housing 13, the flange 7 can not be deformed and the threaded connection ensuring the maintenance of the ring 6 is then perfectly rigid and resists the gun and the shock resulting from the postage of the projectile in the tube of the weapon.

The piston 14 comprises a peripheral flange 14a which is pinched between the ring 6 and the flange 7. This flange ensures the maintenance of the piston 14 in its locking position during the storage and transport phases of the projectile.

The piston 14 also carries an axial extension 17 carrying a bore 18. This extension penetrates through the bore 24 into the chamber 10 which is arranged inside the rear part of the body 2 of the projectile 1.

The extension 17 encloses a valve 19 which can slide freely in a cylindrical bore of the extension 17. A thin shutter of paper or aluminum foil (not shown) can seal the bore 18 and thus ensure the seal with respect to moisture.

The extension 17 is closed at its rear by a perforated shutter 20 on which a rear portion of the valve 19 is applied during firing.

The valve 19 is shown alone in Figures 4a and 4b.

It comprises a cylindrical body which ends with a conical end 19a intended to cooperate with a complementary conical profile 18a arranged on the opening 18 of the piston 14 and which forms a seat for the valve.

The other end of the valve 19 comprises a pin 21 which is surrounded by a shoulder 22.

The body of the valve 19 also carries longitudinal grooves 23 regularly distributed angularly (here four grooves). The grooves 23 open at the shoulder 22.

When the valve 19 bears on the shutter 20, the perforations of the latter are opposite the shoulder 22 and are therefore not closed by the stud 21.

Thus during the firing, the propellant gases that pass through the opening 18 can also enter the chamber 10 of the projectile through the grooves 23 and through the perforations of the shutter 20.

The operation of the device is as follows.

During the internal ballistic phase, the valve 19 is in abutment against the shutter 20 (Figure 2b). The propellant gases pass through the bore 18 (after possibly breaking the sealing straw), they follow the grooves 23 and enter the chamber 10 through the holes of the shutter 20. The pressure then equilibrates between the interior of the chamber 10 and the chamber of the weapon (not shown).

The ring 6 is engaged on the thread of the flange 7. The latter is held firmly by the piston 14 and the mechanical strength of the belt is ensured.

At the exit of the barrel of the weapon, the pressure in the chamber 10 becomes greater than that exerted on the outer face of the piston 14. The gases trapped in the chamber then push the valve 19 to the piston 14. The tapered end 19a of the valve 19 then applies to its seat 18a at the opening 18 of the piston 14 (Figure 2c).

Once in contact with the piston, the valve closes the opening 18. The gases present in the chamber 10 can not escape and then exert their pressure on the inner face of the piston 14. The pressure of the gases causes the shear of the flange 14a of the piston 14. The latter is then pushed backwards and it abuts against the flange 8 of the ring 6.

In the unlocked position of FIG. 2c, the piston 14 no longer prevents flexing of the tongues 15. Indeed, its outer rim has completely cleared from the cylindrical housing 13 of the bottom 9.

The pressure of the gases continues to push the piston 14 which drives the ring 6. A longitudinal force is exerted by the ring 6 on the thread of the flange 7. It has the effect of bending the tongues 15. The ring 6 driven by the piston 14 is ejected (Figure 2d).

The unlocking and ejection of the ring 6 carrying the belt and the release of the expandable empennage by the case 5 then occur in the first meters of the trajectory of the projectile.

Claims (7)

1. An artillery projectile incorporating a body (2) to which a sealing band (4) is fixed, such band being fixed to the projectile body by means of a mounting ring (6) linked to the projectile body by fastening means which can be unlocked upon exiting the gun barrel, such projectile being characterized in that the fastening means comprise a threaded rim (7) to receive the mounting ring (6) of the band, such rim being integral with a base (9) of the projectile and formed of deformable tabs (15) separated by slots (16), such rim (7) furthermore delimiting a cylindrical housing (13) receiving a piston (14) able to slide between two positions: a locking position in which it is engaged in the housing (13), against the rim (7), and prevents the tabs (15) from bending, and an unlocking position in which it releases the tabs (15).
2. An artillery projectile according to Claim 1, characterized in that the piston (14) carries an axial prolongation (17) provided with at least one drill hole, such prolongation penetrating in a chamber (10) arranged inside the rear part of the projectile.
3. An artillery projectile according to Claim 2, characterized in that the prolongation (17) encloses a sliding valve (19) which during firing enables the propellant gases to enter the chamber (10), the gas pressure in the chamber pushing the valve (19) against a seat (18a) integral with the piston (14) upon exiting from the gun barrel.
4. An artillery projectile according to Claim 3, characterized in that the prolongation (17) is closed by a perforated obturator (20) on which a rear part of the valve (19) is applied during firing, this rear part of the valve incorporating a nipple (21) surrounded by a shoulder (22) onto which at least one longitudinal groove (23) of the valve (19) opens out, the propellant gases thus being able to enter the projectile chamber (10) during firing by passing through the groove or grooves (23) and by the perforations in the obturator (20).
5. An artillery projectile according to one of Claims 1 to 4, characterized in that the mounting ring (6) of the band (4) incorporates a stop surface (8) onto which the piston (14) is applied when it is in the unlocking position upon exiting the gun barrel.
6. An artillery projectile according to one of Claims 2 to 5, characterized in that the chamber (10) arranged in the rear of the projectile encloses a block (11) of propellant charge ensuring a reduction in the aerodynamic drag during the trajectory.
7. An artillery projectile according to Claim 6, characterized in that the threaded rim (7) is integral with a base (9) ensuring partial closing of the chamber (10).

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