EP1431702A1 - Ammunition fuze comprising a safety device linked to the outside environment - Google Patents

Abstract

The priming fuse, incorporating a safety mechanism that prevents arming of the munition, has a vane (25) that catches the wind as the munition leaves the barrel of the launch weapon, e.g. a mortar. As the vane deploys, it pulls out a locking pin (33) that releases a barrel (17) with a detonator, aligning it with the pyrotechnic circuit. Further movement disengages the vane altogether, as a slot (29) aligns with its pivot pin (31) and disengages it.

Description

The present invention relates to an ammunition rocket including security preventing cocking of the rocket. It applies in particular to the rockets intended to start the ammunition fired in the smooth core materials.

The rocket is intended to initiate a projectile of ammunition. The projectile may contain an explosive or smoke charge. Standard STANAG 4187 (NATO) stipulates that a rocket must authorize the initiation of the projectile only on condition that two independent events, showing that the ammunition has been fired, come true. The rocket therefore includes safety devices, which, when activated, prevent the rocket from being cocked. These safeties are deactivated when events occur. Once the armed rocket, it can initiate the projectile.

Electronic devices can be used to activate or deactivate the safety devices. Safeties can be themselves e. These devices require energy to operate. This energy can be stored in a battery for example. This presents a disadvantage, because you have to check regularly that the battery is charged. A goal of the invention is to provide a rocket which makes it possible to deactivate a safety when an external event takes place, without using on-board energy.

To this end, the invention relates to a munition rocket comprising at least one safety device preventing cocking of the rocket, a flap having a catch in the wind, arranged to be moved under the effect of the aerodynamic force exerted when the rocket moves, the shutter being mechanically linked to security to deactivate it when the shutter is set in motion.

The invention has the advantage of being simple to implement and to be economical. It is entirely mechanical, which makes it reliable. She can be used on rockets using a pyrotechnic chain misaligned, of which at least one element is kept misaligned by at least security.

According to an advantageous embodiment, the rocket comprises in in addition to means for releasing the shutter when the security is deactivated. This avoids disturbing the aerodynamics of the rocket once the security has been disabled.

According to another advantageous embodiment, the rocket being intended to be loaded in ammunition, the flap has a weight minus 50 times less than the weight of the ammunition with the rocket. So, we avoids disturbing the kinematics of the ammunition when the flap is put in movement.

According to another advantageous embodiment, the rocket includes holding means for holding the shutter in a position of rest, the flap deviating from its rest position when it is put in movement. These means make it possible to avoid inadvertent movement of the flap when the ammunition is handled before firing, especially when the servant (person handling the ammunition) places the ammunition in a mortar, or when setting up (screwing the rocket to the projectile) of the rocket.

• la figure 1 représente un mortier et une munition ;
• la figure 2 représente une munition ;
• les figures 3 à 6 et la figure 9 représentent une fusée comprenant une chaíne pyrotechnique destinée à être initiée par un percuteur, dans des vues en coupe, dans différentes positions entre le moment où la chaíne pyrotechnique est désalignée et celui où le percuteur initie la chaíne pyrotechnique ;
• les figures 7 et 8 représentent plus en détail l'élément de la chaíne pyrotechnique qui est désaligné ;
• les figures 10 à 17 représentent une fusée munie d'un volet selon l'invention dans différentes positions.

Other characteristics and advantages of the invention will become apparent from the following description given with reference to the appended drawings:

• Figure 1 shows a mortar and ammunition;
• Figure 2 shows ammunition;
• Figures 3 to 6 and Figure 9 show a rocket comprising a pyrotechnic chain intended to be initiated by a striker, in sectional views, in different positions between the time when the pyrotechnic chain is misaligned and that when the striker initiates the chain pyrotechnics;
• Figures 7 and 8 show in more detail the element of the pyrotechnic chain which is misaligned;
• Figures 10 to 17 show a rocket with a flap according to the invention in different positions.

We now refer to Figures 1 and 2. The rocket F can be screwed on a C projectile, at the head of the projectile. A propellant P, comprising stabilization fins, is fixed to the foot of the projectile. The ammunition is the unit formed by the propellant P, the projectile C and the rocket F. The projectile is placed in a barrel tube of an M mortar to be fired.

We now refer to Figures 3 to 9. The rocket includes a fixed rear body 18 and a movable front body 4 in which are housed all mechanical and pyrotechnic parts. The rear body and the body front are joined by a ring 8.

The front body 4 has an upper cavity and a cavity lower. The upper cavity is closed by a striker head 1 supported by a spring 2 and equipped with a striker 3. The lower cavity receives a piston 5 which carries a primer 6. The piston is locked until departure of the ammunition by two balls 9, maintained by a ring of safety 7. The ring is itself immobilized by a spring 10.

The rear body 18 mainly comprises a cavity upper, a middle cavity and a lower cavity. The upper cavity receives the front body 4, a locking plate 13 and a ring provided lugs 12 enabling the ammunition to immobilize the ring safety 7. The piston 5 will then be pushed towards the striker 3 by a spring 11. The middle cavity contains a device for interrupting the chain pyrotechnic. This device comprises a cylinder 17 forming a barrel. The barrel 17 is held in a safety position by a tube 23 of fire transmission. This tube forms part of the piston 5. The barrel 17 has a bore 21. The cavity containing the barrel can be closed by a transparent cap 15 which allows the position of the barrel to be observed. The bore 21 opens onto a detonator 20 placed in the barrel 17. A torsion spring 16 is placed between the barrel 17 and the transparent cap 15. An excitation roll (pentrite) 22 is placed between the middle cavity and the lower cavity. The lower cavity contains a priming bar 19 in hexogen wax.

Before the ammunition leaves, the rocket is screwed into a projectile housing. The front body is put in a firing position.

We refer to Figures 4 and 5. By inertia, the springs are swallowed towards the rear part of the rocket as well as the safety ring 7. This allows the balls 9 to move apart and release the primer-carrying piston 5. The safety ring remains attached to the lugs of the ring 12.

When the ammunition leaves the barrel, the advancing piston gradually under the force of the spring 11 extracts its rear part (shaped barrel). This movement is slowed down by the compression of the air which is on the front of the rocket. The barrel 17 and tube 23 assembly forms a first security which is deactivated by a first external event, acceleration of the rocket.

Reference is made to FIGS. 6 to 8. When the piston has finished its forward movement, the barrel is finally released from the tube 23 which hindered it. The barrel rotates approximately 60 ° bringing it from the position shown in Figure 7 at the position shown in Figure 8. In this position, the rocket is armed. The recess 21 opens onto the tube 23 fire transmission. Detonator 20 is aligned with primer 6. The point of the striker is in contact with the paillet of the primer.

We refer to Figure 9. At the time of impact, the striker, by crushing, compresses the spring 2, while the piston 5 is precipitated forward. The point of the striker penetrating the primer causes its detonation. The flame passes through the tube 23 of the piston and ignites the detonator 20. Then, the excitation bar 22 bursts in turn causing the detonator the priming bread 19.

We now refer to Figures 10 to 17. We describe a example of implementation of the invention, applied to the rocket described above, to which a second security can be deactivated by a second external event. We thus obtain a rocket meeting the STANAG 4187 safety provisions, without using onboard energy.

Figure 10 shows the rocket in a rest position intended for storage and transport. Rocket F includes a flap 25. The flap 25 is held in place by a pin 31 at its base on the one hand, and by a shear pin 32 on the other hand. Axis 31 is substantially perpendicular to the direction of movement of the rocket. Axis 31, in incomplete contact with the flap 25, prohibits rotational movements of the flap 25 along axes perpendicular to axis 31. In this position of the rocket, the axis 31 is in contact with a first surface 27 of the flap. The pin 32 prevents the translational movement of the shutter in the direction of rocket movement. The pin 32 is tightened in the shutter, which also prohibits the rotational movements of the flap 25 along the axis 31.

A locking pin 33, placed in the rocket so removable, is in mechanical contact with the flap. This contact is made at level of a shoulder 26 of the flap. The door locking pin preferably a seal 34 (see Figure 17). It thus seals of the rocket in storage, i.e. when the locking pin 33 is in the rocket. The locking pin 33 is in contact, inside the rocket, with the barrel 17 carrying the detonator. In position in the rocket, the axis of locking prevents complete rotation of the barrel.

The barrel 17 and locking pin 33 assembly forms a second security preventing cocking the rocket. When the first security is deactivated by acceleration of the rocket, the barrel 17 begins a rotational movement tending to align the pyrotechnic chain. This movement is stopped by the locking pin 33 before the rocket is army. The axis 33 can be arranged to stop the rotational movement of the barrel halfway, ie 30 °.

Figure 11 shows the rocket in a position where it has undergone acceleration, but is still in the mortar barrel. The acceleration causes the flap 25 to sink in the direction of moving the rocket. The pin 32 shears during this insertion. The pin 31 comes into contact with a second surface 28 of the flap, opposite of the first surface 27.

According to a preferred embodiment, the flap 25 is ballasted with so as to place its center of gravity as close as possible to the rocket. The combination of local lateral overpressure in the barrel and of this ballast prevents the opening of the shutter as long as the shutter is in the barrel. Ballasting can be achieved by adding a piece 35 (see Figure 17) of denser material than the shutter.

Figures 12 to 14 show the rocket in an off position of the barrel tube. Lateral overpressure is no longer exerted on the shutter. Strength aerodynamics exerted on the head 30 of the flap causes the start of the opening movement. During this movement, the flap turns around the axis 31. The flap drives the locking pin 33 out of the rocket.

Figures 15 and 16 show the continuation of the movement of the flap. In this position, the locking pin 33 is outside the barrel 17. The force aerodynamics (second external event) deactivated the second security, thus authorizing the alignment of the pyrotechnic chain. The barrel 17 ends its rotational movement, aligning the pyrotechnic chain. The rocket is then armed.

Figure 17 represents a final stage in the movement of the flap in which the flap and the locking pin are separated from the rocket. The movement of the shutter leads it into a position where it escapes. Axis 31 leaves the shutter by an exhaust 29 provided in the shutter. The continuation of operation of the rocket is that described in relation to FIGS. 8 and 9.

According to a preferred embodiment, the exterior of the shutter is shaped (not shown) so as to have a rounded shape. This prevents accidental opening of the flap when handling the rocket, in combination with the shear pin 32.

Of course, the invention is not limited to this example of production. The locking piece 33 can be integral with the flap. Through example the flap and the locking piece can be replaced by a single plastic part having a joint produced by folding.

The mechanical action of the safety component can be performed differently. It can be done by removing or breaking a part forming an obstacle to a rotational or translational movement. The room can be broken by shearing.

The rocket may have more or less safety. These may be of different shape.

Claims (6)

Ammunition rocket comprising at least one safety device (17, 33) preventing the rocket from being cocked, characterized in that it also comprises a flap (25) having a catch in the wind, arranged to be set in motion under the effect of the aerodynamic force exerted when the rocket moves, the flap being mechanically linked to safety to deactivate it when the flap is set in motion. Rocket according to claim 1, comprising means (29) for dropping the shutter when security is disabled. Rocket according to any one of the preceding claims in which, the rocket being intended to be loaded in ammunition, the flap has a weight at least 50 times less than the weight of the ammunition with the rocket. Rocket according to any one of the preceding claims, comprising holding means (32) for holding the shutter in a rest position, the flap deviating from its rest position when it is put moving. Rocket according to claim 4, in which the holding means are formed by a shear pin. Rocket according to any one of the preceding claims in which security comprising a part (33) obstructing a movement to arm the rocket, the movement of the flap removes or breaks the room to disable security.

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