Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F42—AMMUNITION; BLASTING
  • F42C—AMMUNITION FUZES; ARMING OR SAFETY MEANS THEREFOR
  • F42C15/00—Arming-means in fuzes; Safety means for preventing premature detonation of fuzes or charges
  • F42C15/005—Combination-type safety mechanisms, i.e. two or more safeties are moved in a predetermined sequence to each other
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F41—WEAPONS
  • F41A—FUNCTIONAL FEATURES OR DETAILS COMMON TO BOTH SMALLARMS AND ORDNANCE, e.g. CANNONS; MOUNTINGS FOR SMALLARMS OR ORDNANCE
  • F41A19/00—Firing or trigger mechanisms; Cocking mechanisms
  • F41A19/58—Electric firing mechanisms
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F42—AMMUNITION; BLASTING
  • F42C—AMMUNITION FUZES; ARMING OR SAFETY MEANS THEREFOR
  • F42C11/00—Electric fuzes
  • F42C11/008—Power generation in electric fuzes
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F42—AMMUNITION; BLASTING
  • F42C—AMMUNITION FUZES; ARMING OR SAFETY MEANS THEREFOR
  • F42C15/00—Arming-means in fuzes; Safety means for preventing premature detonation of fuzes or charges
  • F42C15/24—Arming-means in fuzes; Safety means for preventing premature detonation of fuzes or charges wherein the safety or arming action is effected by inertia means
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F42—AMMUNITION; BLASTING
  • F42C—AMMUNITION FUZES; ARMING OR SAFETY MEANS THEREFOR
  • F42C15/00—Arming-means in fuzes; Safety means for preventing premature detonation of fuzes or charges
  • F42C15/40—Arming-means in fuzes; Safety means for preventing premature detonation of fuzes or charges wherein the safety or arming action is effected electrically

Definitions

• the technical field of the invention is that of rockets for projectiles intended to be fired by a cannon.
• Projectiles fired by a cannon are associated with a propellant charge which, once ignited, generates propellant gases, the pressure of which allows the projectile to be fired.
• projectiles can be in the form of cartridge ammunition, in which the projectile is integral with a case which contains the propellant charge and which carries an igniter for this charge.
• projectiles can also be independent of the propellant charge associated with them only at the time of firing, for example for mortar firing.
• the projectiles are equipped with a fuse that commands the firing of an explosive charge or a pyrotechnic charge, at a given moment on the trajectory, or on impact on a target.
• the rocket conventionally has a safety and arming device that guarantees safe firing.
• US Pat. No. 6,951,161 proposes to associate the detection of firing acceleration with the counting of a certain number of rotations of the projectile in a given time window.
• Such a solution requires the installation of a rotation sensor, for example magnetic, which complicates the definition of the rocket.
• Patent application US2008 / 0210115 describes a safety device in which the second event associated with firing consists of a measurement of the pressure or temperature at the warhead of the projectile. Such a solution is also complex and expensive to implement.
• Patent FR2633385 discloses a device in which the gas pressure in the chamber of the weapon is detected by pistons which perforate a wall of the projectile to release a security. This device is also complex and can lead to leaks between the projectile and the chamber of the weapon.
• Patents US5097765 and US3814017 show devices incorporating one or more capacitors which function to power the electronic circuits of the rocket and to provide the energy for firing the detonator. These capacitors incorporated in the firing chain cannot constitute firing safeties either making it possible to make a rocket conform to military standards.
• the rocket according to the invention is particularly well suited to the definition of rockets for projectiles and ammunition that can be fired from smooth tubes.
• the invention also relates to a munition equipped with such a rocket and a method of arming such a rocket.
• the subject of the invention is a rocket for a projectile intended to be fired by a cannon by the ignition of a propellant charge by an electric ignition means, such as an electric igniter, a rocket capable of passing from a safety position. in an armed position, following firing, by lifting at least two different safety devices, rocket characterized in that it comprises a capacitor which is intended to be connected to the means of electric ignition of the propellant charge and which is charged when the latter is ignited, and also a computer which detects the charge of the capacitor to allow the arming of the rocket when this charge is greater than or equal to a reference value, the charge of the capacitor constituting a first safety of shoot.
• an electric ignition means such as an electric igniter
• the rocket may include an electric generator which is initiated by inertia during firing.
• the rocket may include an inertial sensor which is connected to the computer and which constitutes a second firing safety device.
• the rocket may have a divider bridge between the electric ignition means and the capacitor.
• the capacitor of the rocket may be placed between the gate and the source of a field effect transistor, the drain of this capacitor being supplied by the electric generator and being connected to a logic module of the computer, the source also being connected to a ground of the rocket, the threshold voltage V GS of the transistor constituting the reference value.
• the subject of the invention is also a munition which is intended to be fired by a cannon and comprising a projectile and a propellant charge equipped with an electric ignition means, such as an electric igniter, fixed to a base, the projectile carrying a rocket according to the preceding characteristics and a wire link connecting the rocket to the igniter.
• an electric ignition means such as an electric igniter
• the munition can include a divider bridge between the electric ignition means and the capacitor, which divider bridge is housed in the base.
• the subject of the invention is also a method of arming a rocket fitted to a projectile during firing by a gun, a method in which the firing is recognized by the detection of at least two different events usually associated with a firing. , the combination of the two events making it possible to arm the rocket, a process characterized by the following steps: - a rocket capacitor is charged from a firing signal of a propellant charge, - the charge of the capacitor is used as a first event associated with the firing and allowing the arming of the rocket, a computer detecting the charge of the capacitor to allow the arming of the rocket when this load is greater than or equal to a reference value .
• the firing acceleration can be used as a second event associated with firing and allowing the rocket to be armed
• an electric generator is used in this process which is initiated by inertia during firing, the activation of the generator ensuring the power supply to the rocket.
• FIG. 1 is a schematic view in partial longitudinal section of a munition according to the invention.
• FIG. 1 shows an embodiment of a rocket according to the invention.
• an ammunition 1 according to the invention is intended to be fired by a gun (not shown), for example a gun with a caliber greater than or equal to 40mm, such as a 120mm tank gun.
• This munition 1 comprises a projectile 2 and a propellant charge 3, in the form of grains of powder, and which is housed in a case 4, for example combustible.
• the sleeve 4 is closed at its rear part by a metal base 5 which carries an annular seal 5a.
• the base 5 has an axial bore which receives an electric ignition means 6 (such as an igniter), integral with an igniter tube 7.
• Caps equipped with igniter tubes are well known to those skilled in the art. Reference may be made, for example, to patents EP2108916 and EP1258695 which describe obturating caps fixed to fuel sockets and to patent EP1106959 which describes an igniter tube.
• Patent EP307307 describes an example of a connecting piece between a projectile and a combustible socket.
• the projectile 2 carries at its rear part a deployable tail unit 10, mounted to pivot on axes integral with a tail unit 11.
• the projectile 2 is for example an explosive projectile whose metallic body contains an explosive material (not shown).
• the explosive material is likely to be initiated by a fuse 11 (shown in dotted lines) which is housed in a base 2a of the projectile 2.
• the rocket 11 is connected to the igniter 6 (or more precisely to the electrical contact supplying the igniter 6) by a wire connection 12.
• the wire connection 12 could for example be glued to the wall. internal of the fuel sleeve 4.
• the rocket 11 can also be a programmable rocket. We can therefore associate the wire link 12 connected to the igniter 6 with another wire link (not visible in Figure 1) which will be connected to a contact pad of the base making it possible to introduce programming signals from the rocket 11 before firing.
• FIG. 2 schematically shows the rocket 11 of the projectile 2.
• the rocket 11 includes a safety and arming device 13 which here carries a detonator 14 secured to a movable shutter 15.
• the detonator 14 is intended to initiate the explosive charge 16 which is housed in the body of the projectile 2.
• This security and arming device 13 is not shown in detail because such devices are well known.
• the movable shutter 15 (in rotation or in translation) makes it possible to misalign the detonator 14 and the explosive charge 16 (or more precisely to misalign the detonator 14 and an orifice 17 allowing the passage of the detonation wave and which allows it to attack the explosive charge 16).
• the safety and arming device 13 changes from a safety position (in which the detonator 14 cannot initiate the explosive charge 16) to an armed position in which the detonator 14 is effectively aligned with the port 17, and can therefore detonate the explosive charge 16.
• This passage from the safety position to the armed position can only be done by lifting at least two different safety devices, which takes place following the firing of ammunition 1.
• the rocket 11 thus comprises a computer 18 which is intended to control the passage of the safety and arming device 13 to its armed position.
• the computer 18 is produced, for example, in the form of a microprocessor which is supplied with energy by an electric generator 19.
• wire link 21 which connects the computer 18 to a programming contact integral with the base 5.
• This wire link is intended to introduce into a memory of the computer 18 a programming value, for example chronometry. firing.
• the electric generator 19 is advantageously a generator which is initiated by inertia during firing, for example a bootable battery.
• Such generators are well known (see for example the patents US7504177, DE50115732 and US9647276). They include an electrolyte that is contained in a broken bulb due to inertial forces when fired. The electrolyte is thus positioned between the electrodes of the battery which can then deliver a current.
• thermal cell comprising a pyrotechnic composition which is initiated by a striker released by the firing acceleration.
• thermal batteries are also well known, for example from the patents: EP2573850, WO2017069787, US5458995 and US10062910.
• the rocket comprises a capacitor 20 which is connected by wire link 12 to an electric ignition means of the propellant charge, here the igniter 6.
• the capacitor 20 is mounted in parallel with the igniter 6 and it is part of the firing current of the initiator 6 which is thus diverted to the capacitor 20 which therefore only charges at the time of the actual firing. of the projectile 2.
• a voltage divider can be provided which will be housed in the vicinity of the initiator 6. This solution will be described later.
• Figure 2 is very schematic and one terminal of capacitor 20 is connected to the supply pole of igniter 6 while the other terminal of capacitor 20 is to the electrical ground of the weapon.
• This grounding is made through the obturator base 5 (as for the igniter) and the wire link 12 is then a two-wire link. Grounding can also be done by the body of the projectile 2 which is in contact with the barrel of the weapon (and the wire link 12 can then be single-wire).
• the capacitor 20 is connected to the computer 18 which can thus detect the charged state or not of the capacitor 20.
• the computer 18 is also not supplied with energy before firing since it is the activation of the electric generator 19 by the acceleration of the firing that supplies it with current.
• the computer 18 will measure the charge level of the capacitor 20, for example by comparison with a reference value stored in memory, or more simply by switching a solid state relay whose switching level (reference value) is set by an electronic circuit (incorporated in the rocket 11) at a level corresponding to the minimum discharge current of the capacitor 20 which is expected.
• the method of arming a rocket according to the invention thus comprises the following two steps:
• a rocket capacitor is charged from a firing signal of a propellant charge
• the capacitor charge is used as a first event associated with firing and allowing the rocket to be armed.
• the computer 18 does not then control the arming of the safety and arming device 13 and the detonation of the explosive charge 16 cannot take place.
• the second firing safety consists of an inertial sensor (such as an accelerometer 22) which detects the firing acceleration.
• the accelerometer 22 is connected to the computer 18 which includes a logic module verifying the presence of the two events, which frees the safety and arming device 13 of the rocket 11.
• the safety and arming device 13 of the rocket 11 can therefore only switch from a safety position to an armed position following the lifting of two different safeties: the detection of the ignition current of the propellant charge and the detection of longitudinal firing acceleration.
• An accidental ignition of the propellant charge for example following a fire, can also not remove the arming safety since the electric current intended for the igniter 6 is then absent and could not charge the capacitor 20.
• a rocket 11 is defined that meets the highest security requirements without it being necessary to provide the security and arming device with an additional inertial lock.
• the capacitor 20 is functionally attached to the fuse 11, it can structurally be placed outside the fuse, for example in a specific housing of the projectile body 2.
• the computer 18 of the rocket 11 will itself constitute the safety and arming device, without it being necessary to provide a movable shutter 15.
• detonator 14 of the type with projected element (better known under the Anglo-Saxon term of "Slapper”).
• These detonators are relatively insensitive and can only be activated by a high voltage and moreover they deliver enough energy to initiate a secondary explosive, so the sensitivity is also reduced. It is therefore possible (and authorized by the standardization bodies) to use a slapper without a mechanical shutter ensuring a pyrotechnic chain misalignment, but on the condition of having two independent firing safety devices controlling the operation of the rocket.
• the firing safety is then ensured by the rocket 11 itself which can only control the slapper after the two firing safeties have been raised.
• the firing safeties will be logical locks independent of each other and which must be distinct from the firing chain itself.
• FIG. 3 shows an exemplary embodiment of a rocket 11 according to the invention and incorporating a projected layer detonator 14.
• the wire link 12 is connected to the initiator 6 by a voltage divider bridge 23 which comprises two resistors R 1 and R 2 .
• the voltage u conveyed by the wire link 12 is reduced with respect to the voltage U for igniting the igniter 6.
• We au UR 2 / (R 1 + R 2 ).
• the capacitor 20 is supplied through a load resistor R 3 , another resistor R 4 is mounted in parallel between the terminals of the capacitor 20.
• the purpose of resistor R 4 is to allow the discharge of the capacitor 20, after detection of its state loaded by the computer 18, during the flight of the projectile. It thus makes it possible to evacuate the parasitic charges which could disturb the operation of the rocket.
• R 3 and capacitor 20 in fact form a low-pass filter making it possible to eliminate the high parasitic frequencies
• the ignition of the igniter 6 igniting the propellant charge therefore causes the charge of the capacitor 20.
• the rocket comprises a field effect transistor (MOS) 24, the drain (D) of which is supplied by the electric generator 19 (when the latter is started).
• MOS field effect transistor
• the capacitor 20 is disposed between the gate (G) and the Source (S) of the transistor 24.
• the electric generator 19 When the electric generator 19 is started, it supplies the computer 18 (link 25) but it also applies a voltage V DS , via the link 26, to a logic module 27 of the computer 18.
• the MOS transistor 24 closes and the current coming from the generator 19 is evacuated to the mass 28 by the link 29. This results in a voltage close to 0 volts applied to the logic module 27 of the computer via the link 26.
• the load resistor R 5 makes it possible to avoid short-circuiting of generator 19.
• the logic module 27 detects the firing acceleration seen by the accelerometer 22.
• the components and the logic wiring are chosen such that only the conjunction of the presence of a firing acceleration and a charge of the capacitor 20 makes it possible to activate the operation of the rocket 18, and in particular of a module. 30 for managing the firing of the slapper 14 detonator.
• the rocket 11, and more particularly the firing management module 30, also receives, as described above, the wired link 21 allowing the programming of the desired operating mode for the rocket.
• the first firing safety device uses information of an electrical nature which is stored in the rocket 11 before the latter can operate, the electrical generator 19 not yet being operational.
• the timeline of a shot is fast enough that the stored information can be read by the rocket when it can operate.
• the discharge of capacitor 20 only takes place gradually, through resistor R4, after the safety has been released.
• the capacitor 20 is not involved in the firing of the Slapper 14 detonator. The energy for this firing comes from the electric generator 19.
• the invention is more particularly suited to ammunition fired from a smooth weapon tube. It is clear, however, that it can very well be implemented with ammunition fired from a rifled tube.
• the firing event associated with the ignition of the propellant charge can then be combined with an axial acceleration of the projectile or an acceleration of rotation.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Air Bags (AREA)
• Automotive Seat Belt Assembly (AREA)
• Aiming, Guidance, Guns With A Light Source, Armor, Camouflage, And Targets (AREA)

Applications Claiming Priority (2)

Publications (2)

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Family Applications (1)

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Family Cites Families (21)

• 2019
  • 2019-02-13 FR FR1901348A patent/FR3092660B1/fr active Active
• 2020
  • 2020-02-06 EP EP20710273.2A patent/EP3924686B1/de active Active
  • 2020-02-06 WO PCT/IB2020/050945 patent/WO2020165699A1/fr not_active Ceased
  • 2020-02-06 US US17/429,777 patent/US11774225B2/en active Active
• 2021
  • 2021-08-09 IL IL285468A patent/IL285468B1/en unknown

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